Next Article in Journal / Special Issue
Conversion of Unsaturated Short- to Medium-Chain Fatty Acids by Unspecific Peroxygenases (UPOs)
Previous Article in Journal / Special Issue
Perspectives on Using a Competitive Exclusion Approach to Control Listeria monocytogenes in Biological Soil Amendments of Animal Origin (BSAAO): A Review
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Yeast and Virus-like Particles: A Perfect or Imperfect Couple?

Yeast Genetics and Genomics Group, Institute of Clinical Physiology, National Research Council (CNR), 56124 Pisa, Italy
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Submission received: 9 June 2023 / Revised: 5 July 2023 / Accepted: 5 July 2023 / Published: 14 July 2023

Abstract

:
Virus-like particles (VLPs) comprise viral structural proteins that self-assemble to form a particle similar to the native virus capsid. Since their discovery, they have been employed mainly as vaccines to prevent viral infection because they can elicit an immune response. Besides their use as vaccines, their application in cancer prevention and drug delivery is under intensive investigation. They can be produced in different systems such as bacteria, mammalian, plant, insect, and yeast cells. The main hurdle for their use is establishing a platform for production because many variables need to be considered. First, VLPs must be effective in the action for which they are constructed, depending on the nature of the VLPs. Second, the production platform must be suitable for safe and high-scale production. Yeast has been shown to be a valuable tool in VLP production, as it is able to express heterologous proteins efficiently and its manipulation is cheap and easy. Several species have been employed for this purpose. In the present review, we analyze the features of different yeast species and how they have been used to produce VLPs.

1. Introduction

Several structural viral proteins can self-assemble to form a capsid without a viral genome. This property of viral proteins has been exploited for constructing virus-like particles (VLPs). The most important feature of VLPs is that they resemble the capsid of the original virus, but they are empty shells that do not contain the viral genome, and thus, they elicit an immune response without propagating inside the cells. Although the number of articles dealing with VLP production has tremendously increased after the COVID-19 outbreak, the concept of VLPs was first postulated in 1955 when Fraenkel-Conrat and Williams observed that inactive proteins of the Tobacco mosaic virus were able to assemble into particles, producing lesions in the leaves similar to the virus [1]. Ten years later, VLPs were found in the liver cells of patients with infectious hepatitis [2]. Since then, VLPs have been produced in mammalian cells [3,4] and Escherichia coli [5], and have been identified in Saccharomyces carlsbergensis [6] and Saccharomyces cerevisiae during investigations of killer yeast strains [7,8]. Indeed, these kinds of viruses have been observed in several fungi, such as some Penicillium species, Aspergillus foetidus, and Ustilago maydis [9]. This observation has prompted researchers to use yeast to study genome replication and encapsidation [10,11]. Recently, VLP production has also started in plants [12,13] and insect cells [14].
The characteristics of VLPs make them a cheap and safe tool for producing vaccines and immunogens [15]. Several VLP-based vaccines are on the market and are used in humans, including Recombivax HB and Engerix-B for human hepatitis B virus (HBV), Gardasil, Cervarix, and Gardasil-9 for human papillomavirus (HPV), and Hecolin for hepatitis E virus (HEV), which are produced in bacteria, yeast, and insect cells [16], or in clinical trials, such as the seasonal influenza virus manufactured in plants [17]. In virology, they are widely used in investigations on virus assembly [18]. In addition, VLPs can be exploited as carriers for the delivery of drugs and imaging substances in light of their empty inner space [19,20]. There is also growing interest in applying VLPs in cancer prevention and therapy [20,21]. Moreover, yeast VLPs have been exploited as a carrier for DNA and drugs. Examples of yeast-based VLPs used as carriers are HBV-VLPs filled with DNA plasmids or calcein with electroporation and then used to infect hepatocellular carcinoma cells and human carcinoma xenografts in mice [22]. VLPs applied in cancer prevention include vaccines against viruses involved in the pathogenesis of human cancer, such as HBV and HPV. On the other hand, VLPs exploited for cancer therapy are constructed with cancer-specific antigens capable of boosting the immune response against cancer cells. VLPs are generally produced in several systems, such as bacterial, plant, mammalian, insect, and yeast cells (Figure 1).

1.1. Types of VLPs

There are several critical steps to consider when a VLP production platform needs to be developed. First, we must consider the structural complexity of the virus of origin of VLPs, which can be classified as enveloped or non-enveloped (Figure 2). Enveloped viruses are made of single or multiple proteins surrounded by an envelope of the phospholipid bilayer derived from the host cell membrane, due to the budding or the secretory pathway. The specificity of the envelope is determined by the presence of viral glycoproteins [23]. Not all production systems can generate enveloped VLPs containing properly glycosylated proteins. Glycosylation is a post-translational modification (PTM) crucial for a protein to fulfill its biological activity and have the correct folding. This aspect is important in the case of heterologous protein expression because misfolded proteins can be promptly degraded by the ubiquitination pathway or retained in the endoplasmic reticulum (ER). The most suitable expression systems are those based on mammalian and insect cells that perform complex PTMs and the formation of an envelope. Bacteria do not have the enzymes to introduce PTMs, so enveloped VLPs cannot be produced in this organism. Yeasts can make most standard PTMs; however, glycosylation in yeast shows some differences from that occurring in human cells. Two main glycosylation types in eukaryotic cells (N-linked and O-linked) occur in the ER or Golgi apparatus. While the biological role of O-glycosylation is poorly characterized, N-glycosylation is crucial for protein function. N-linked glycosylation consists of high mannose glycan (hyper mannose type) in yeast, whereas in human cells, in addition to high mannose glycan, hybrid glycans and complex glycans are attached to the nitrogen residues of asparagines (Figure 3).
Formation of non-enveloped VLPs is more straightforward and occurs in the presence of nucleocapsid proteins. The simplest viruses are those with one type of capsid protein, while the most complex are composed of several proteins [15]. The problematic issue in producing VLPs resembling capsids consisting of multiple proteins is to maintain the native stoichiometry that is dependent on the concentration of each single protein. The expression of capsid proteins is tightly regulated by alternative splicing and translation start sites [24,25]. This condition must be reproduced in the expression system to build VLPs able to enter inside the cell or stimulate an immune response. These types of virus are efficiently produced in mammalian and insect cells, bacteria, and yeast.

1.2. Critical Points in VLP Production

Purification is crucial in VLP production to ensure suitable efficacy and safety for clinical use. Generally, non-enveloped VLPs are not secreted; therefore, they must be purified from the cells by centrifugation, precipitation, ultrafiltration, and chromatography. For this reason, the solubility of VLPs is crucial. VLPs produced in bacteria may have low solubility due to aggregate formation; this also partially reduces the number of VLPs purified despite the high protein expression level. Another issue to be considered is the safety of the product. As the most significant use of VLPs is their administration as immunogenic drugs, safety issues occur in VLPs produced by bacteria because of endotoxins, and also in VLPs produced in insect cells because the expression of proteins occurs in a Baculovirus that, after VLP purification, has to be inactivated.
When VLPs are produced for commercial use, three other aspects must be taken into consideration: timing, scalability, and cost. During the pandemic, we have learnt how time is crucial to limit the diffusion of a virus. Thus, when a VLP-based drug has to be administered to many people, it is crucial to set up production strategies allowing a high yield of viral-based vaccines in a short time. If we consider that the development of a vaccine requires long phase 3 trials, for which companies must produce a large number of doses without knowing whether a vaccine is going to be efficacious and whether it will reach the market, it is important keeping costs as low as possible by mitigating cost/dose and setting up a flexible and scalable manufacturing platform as well.
Despite the fact that mammalian and insect cells represent the best solution to produce effective VLPs resembling the original virus, they are unsuitable for large-scale production because their manipulation is expensive and their growth rate is elevated and thus difficult to scale up. By contrast, bacteria and yeast culturing is cheap and easy, and their growth rate is short and thus scalable. In Table 1, we summarize advantages and disadvantages of the different systems used to produce VLPs.

1.3. General Considerations of Yeast as Expression System

Yeast is a eukaryotic organism that has emerged as an exceedingly attractive expression system to produce heterologous proteins and VLPs. As yeast strains used in the laboratory are nonpathogenic and nontoxic organisms, they are safe and can be manipulated without any special precautions. For this reason, they have been classed as generally considered safe (GRAS). They have several advantages over mammalian-based systems including rapid growth rates, ease of genetic manipulation, inexpensive and locally-available medium requirements, and well-established fermentative growth [26,27,28,29]. These features make yeast-based systems suitable for large-scale production. The genetic manipulation that can be performed on these organisms allows us to modify them in line with the heterologous proteins that need to be expressed. Yeast expression systems also support the production of one or more viral capsid proteins to form and display an extensive repertoire of antigenic sites including discontinuous epitopes and the production of recombinant glycoproteins [16]. Moreover, yeast has a low risk of contamination by adventitious agents. As a result, VLPs of several virus families have been produced in yeast (Table 2).
Traditionally, the yeast of choice in biotechnology has been Saccharomyces cerevisiae; however, other yeast strains are now successfully used to produce VLPs. The significant development of molecular tools, including synthetic promoters for fine-tuning of expression, engineered strains, and CRISPR/Cas9 technology, have driven the generation of strains more efficient in VLP production for different yeast species [31,32,33].
They are grouped as non-conventional yeasts such as Pichia pastoris (Komagataella phaffii) and Hansenula polymorpha (Pichia angusta).
This review aims to compare the features of yeast species that are essential for setting up a yeast-based VLP platform.

2. Saccharomyces cerevisiae

The budding yeast S. cerevisiae is one of the most studied genetic systems and has been used to a great extent for expressing and producing heterologous proteins for therapeutic or pharmaceutical purposes [34]. A great number of expression plasmids have been constructed in S. cerevisiae. These vectors offer a wide choice of promoters of varying strength and selection markers. In addition, these plasmids are usually shuttle vectors that can be propagated in yeast and bacteria, making them useful in gene cloning [35]. Yeast promoters suitable for protein expression can be divided into two main classes: “constitutive” promoters can ensure a stable expression level; in contrast, “dynamic” or “inducible” promoters may drive substantial changes in the expression level in response to environmental stimuli. Strong constitutive promoters that drive high-level transcription are often used for heterologous proteins. These kinds of promoters include promoters of glycolytic genes, such as 3-phosphoglycerate kinase (pPGK1), glyceraldehyde3-phosphate dehydrogenase (pTDH3), triose phosphate isomerase (pTPI1), enolase (pENO2), and alcohol dehydrogenase (pADH1) [36,37,38]. Dynamic control of gene expression can be implemented by using inducible promoters. The bidirectional GAL1/GAL10 promoter (pGAL1/pGAL10, galactokinase/UDP-glucose-4-epimerase) is induced when yeast cells are grown in the presence of galactose [39], and the CUP1 promoter (pCUP1) can be induced by adding copper (II) [40]. There are also promoters that are induced when glucose concentration is low or absent (low-glucose inducible), including the high-affinity glucose transporter promoter (pHXT7) [38,41] and the alcohol dehydrogenase promoter (pADH2) [37,42]. The commercially available episomal plasmid, pYES2, which carries the promoter pGAL1, the origin of replication 2µ, and URA3 as selection marker, is one of the most commonly used systems to express heterologous proteins in S. cerevisiae. Presumably, using an inducible promoter is more appropriate than a constitutive one to avoid toxic effects due to the undesirable misfolding of heterologous proteins; therefore, pGAL1 is widely used in budding yeast to produce VLPs [30]. Plasmid stability is crucial and may profoundly affect protein expression. The endogenous 2µ plasmid has great stability in a complete medium; interestingly, the stability of 2µ derivative vectors in a rich medium strongly depends on the insert size [43]. The main promoters used for the expression of proteins of VLPs are reported in Table 3.
The first VLPs produced in yeast were made in S. cerevisiae and were composed of HBV proteins [44]. The production was so successful that it led to the approval by the FDA of the first yeast-based derived HBV virus vaccine in 1986. Over the years, VLPs of other viruses have been assembled in yeast, confirming that S. cerevisiae is a good model system for manufacturing VLPs [45,46,47]. Most VLPs purified from this yeast are assembled intracellularly and then purified after cell disruption. This procedure is inappropriate for enveloped VLPs because they originate from the budding of the membrane [48,49]. However, Sakuragi et al. demonstrated for the first time that enveloped virus can be produced in S. cerevisiae spheroplasts. Specifically, they produced VLPs of the human immunodeficiency virus (HIV), an enveloped virus, by budding out the particles directly in the medium [50]. The release in the medium of VLPs allows the formation of enveloped VLP and makes purification easier and faster than that of VLPs assembled in the cytoplasm.
VLPs produced in S. cerevisiae are distributed worldwide as vaccines against infectious diseases; for instance, vaccines against HPV and P. falciparum are commercially available [30]. Using a novel engineered S. cerevisiae-based platform, a multigenic VLP from SARS-Cov-2, named PRAK-03202, was developed. Immunization of mice with PRAK-03202 induces an antigen-specific (spike, envelope, and membrane proteins) humoral response and neutralizing potential [51]. In addition, VLPs from yeast have also been used for virus research in order to study capsid assembly and related factors [52,53].
Although VLP production in S. cerevisiae has several success stories, some drawbacks are still ongoing. Standardized methods to extract VLPs from S. cerevisiae are still required for pharmaceutical purposes. In S. cerevisiae, viral proteins are expressed intracellularly in relatively large amounts; this means that they can potentially produce misfolded aggregates that could be toxic for the yeast cells and consequently reduce VLP yield. Additionally, S. cerevisiae has a lower efficiency than other yeasts, including H. polymorpha and P. pastoris, to secrete heterologous proteins [54,55]. However, the secretory pathway of S. cerevisiae has been successfully engineered and the secretion efficiency improved [56]. These strains could be useful for VLP production. VLP yield is also influenced by the fact that S. cerevisiae is unsuitable for high-density culture. This depends on its particular metabolism. The preferred carbon source of S. cerevisiae is glucose metabolized mainly by fermentation with ethanol production. This is because S. cerevisiae exhibits the so-called Crabtree effect: alcoholic fermentation in the presence of oxygen when the glucose concentration exceeds a certain threshold value, even under aerobic conditions. When the glucose concentration is restrictive, ethanol produced during fermentation is used as a carbon source, by a shift to a respiration mode. Other non-fermentable carbon sources, such as lactate, acetate, or glycerol, can also be used by yeast. The shift from one carbon source to another, known as a diauxic shift, determines a growth slowdown necessary to adapt to the alternate carbon source [57]. Another limitation of using S. cerevisiae is the pattern of protein glycosylation that is different from mammalian cells. In this microorganism, N-glycosylation involves adding a high number of mannose sugars (more than 100 mannose residues), which often leads to hyper-mannosylated N-glycans. This modification can result in protein misfolding and prevent its exit from the ER, resulting in the loss of production titers [58,59]. N-linked carbohydrate chains are terminated by mannose attached to the chain via an α1,3 bond, which is allergenic. Synthetic biology, which has been focusing on the engineering of S. cerevisiae, could help to improve or optimize the expression level of viral proteins by choosing the most suitable molecular method and/or toolkit that can give contributions to standardizing the methodology. It is well known that synthetic metabolic pathways must be organized in cellular compartments to avoid interactions with other pathways and increase enzyme activity [60,61]. Currently, many toolkits are commercially available to standardize methods and protocols in S. cerevisiae and other yeasts [62]. All the standard parts of these toolkits are grouped according to plasmid backbone, promoters, and terminators, and are reported in a publicly accessible catalog (http://parts.igem.org/yeast, accessed on 4 July 2023). This catalog could be useful when VLPs from new viruses or newly identified viral variants must be studied or characterized.

3. Pichia pastoris

The history of Pichia pastoris, also named Komagataella phaffii, is more recent than that of S. cerevisiae. Investigations on the possibility of its use for the expression of heterologous proteins started in the early 1990s [63], and greatly increased after the sequencing of the entire genome in 2009 [64]. The expression of heterologous proteins in P. pastoris leads to a higher yield of the protein in comparison to other yeasts, including S. cerevisiae. P. pastoris can grow to densities as high as 130 g/L of dry cell weight enabling the production of grams per liter of heterologous proteins [65]. Unlike S. cerevisiae, P. pastoris is a Crabtree-negative yeast, meaning that it metabolizes glucose by complete oxidation to carbon dioxide and water. The fermentative growth, typical of Crabtree-positive yeasts, generally results in reduced yields when yeast is used as a cell factory because it ensures fast growth at the expense of reduced protein synthesis.
P. pastoris is a methylotrophic yeast, because it can utilize methanol as its sole carbon and energy source. The first step of the methanol metabolism pathway is methanol oxidation by the enzyme alcohol oxidase (AOX) leading to the production of formaldehyde and hydrogen peroxide. To avoid diffusion inside the cells of the toxic hydrogen peroxide, this step is performed inside specialized organelles called peroxisomes. In P. pastoris, two genes code for AOX: AOX1 and AOX2. Specifically, AOX1 is responsible for most of this activity and is expressed only in the presence of methanol as the sole carbon source and repressed by glucose. GAL1 expression in S. cerevisiae is induced by galactose and repressed by glucose, although a low level of expression occurs also in the presence of glucose. The stringent regulation and strong activity of the AOX1 promoter (pAOX1) determine its wide use for recombinant protein production. Most VPLs produced in P. pastoris are expressed under the control of pAOX1 [30]. Although the production of heterologous proteins under the control of this promoter is high, and the growth in methanol represents an advantage in terms of costs, the use of large amounts of methanol poses considerable drawbacks, such as the risk related to its handling and storage and high oxygen consumption. To overcome these limitations, novel P. pastoris strains have been developed. One example is represented by the mutS (methanol utilization slow) strains that are deleted for AOX1, and exhibit a lower methanol consumption rate [66]. One strain of these has been used for the production of Dengue virus (DENV) VLPs [67]. The DENV capsid is composed by multiple copies of three different structural proteins (C, M, and E) surrounded by the host membrane. Although DENV is an enveloped virus, it has been shown that DENV structural proteins M and E, when co-expressed in heterologous hosts, form non-infectious VLPs [68,69], and that co-expression of protein E (E1 and E2) from two different serotypes results in bivalent VLPs able to elicit an immune response in mice [67].
Expression plasmids with constitutive promoters have been developed to avoid using methanol as a carbon source. The most well-characterized constitutive promoter, considered a reference standard for methanol-free expression systems, is the GAP promoter (pGAP). Additionally, other novel promoters have been developed, such as PDF and UPP promoters (pPDF, pUPP) [70,71]. When pGAP is used to express capsid proteins, yeast growth is more straightforward because no carbon source switch is required, and the hazards and costs related to the storage and delivery of large volumes of methanol are eliminated [72]. Constitutive promoters have been used for VLP production for viruses such as DENV [69,73], Coxsackievirus A16 (CA16) [74], high-level production of Hepatitis B surface antigen (HBsAg), and chimeric HPV-HIVL1P18 VLPs [75].
Methylotrophic yeasts possess the capacity to secrete large quantities of correctly folded proteins. Secretion is an important step in VLP production because it simplifies purification, avoiding cell lysis, denaturation, and refolding of proteins. Secretion occurs also in other yeast species, but the advantage of P. pastoris is that it does not secrete proteases and only few endogenous proteins are released in the medium, thus facilitating subsequent purification. Moreover, comparing P. pastoris and mammalian genomes, the secretory pathway of P. pastoris resembles that of mammalian cells. This observation has been confirmed by structural analysis of Golgi apparatus, which, in this yeast species, is arranged in stacks and surrounded by a matrix that seems to fuse cisternae, as observed in mammalian and plant cells [76]. By contrast, in S. cerevisiae, Golgi cisternae do not stack and are individually scattered in the cytoplasm. One of the most frequently used secretion signals is the N-terminal portion of the pre-pro α-factor from S. cerevisiae. Several VLPs containing this signal are efficiently secreted; however, in some cases, pre-pro α-factor can induce the formation of aggregates, causing mislocalization and poor secretion. To address this issue, several attempts focused on modifying the α-factor with mutations, codon optimization, or inclusion of spacer sequences have been performed [77]. It has been shown that the replacement of the α-factor signal sequence with the Ost1 signal sequence, which directs co-translational translocation across the ER membrane, strongly increased the secretion of msGFP in P. pastoris [78]. Recently, Duan et al. identified new signal sequences showing higher secretion stimulation than the canonical α-factor [79]. In addition, as protein secretion is a complex process, a secretion library has been created to explore a wide range of secretion constructs [80]. Another strategy identified to improve protein secretion is the overexpression of genes involved in the unfolded protein pathway (UPR), such as Hac1p, chaperons Pdi and Ero1, or the ER lumen chaperone Kar2p, so far applied for the secretion of recombinant proteins and not for VLPs [81].
A success story of VLP secretion in P. pastoris is that of Norovirus (NoV) main structural protein VP1. VP1 was successfully expressed and secreted using the methanol-inducible promoter and the α-factor for secretion. NoV VLPs, purified directly from the culture medium, resulted in a total yield greater than 0.6 g/L, with a final purity product over 90%, and are capable of binding the Histo-Blood Group Antigen (HBGA) [82]. Secreted VLPs were also obtained for CA16 [74]. In this study, the authors developed a P. pastoris-based system for secretory expression of the VLPs for CA16 composed of VP0, VP1, and VP3 capsid subunit proteins. Secreted Cowpea chlorotic mottle virus (CCMV) VLPs were obtained with a yield of approximately 95 mg/L of CCMV and with a purity >90% [83]. Many other VLPs were obtained through secretion, such as VLPs for DENV, the enveloped Tick-borne encephalitis virus (TBEV) [84], HPV16 L1 capsid protein, [85,86] and Chikungunya virus (CHIKV) [87].
For the successful production of VLPs, it is crucial to know the role of glycosylation in virus biology. Viral glycoproteins can have a fundamental role in the enveloped virus assembly, in the entry inside the cells, as well as in the stimulation of the immune response. Thus, glycosylation must be taken into consideration during the design of the strategy of VLP production [88]. Compared to S. cerevisiae, P. pastoris has a shorter and less immunogenic glycosylation pattern, and for this reason is preferred over S. cerevisiae as a platform for producing glycosylated proteins. Several glycosylated VLPs have been produced in P. pastoris. The E protein forming the capsid of the Japanese encephalitis virus (JEV) is a 53 kDa protein containing a single potential carbohydrate attachment site. When expressed in P. pastoris for VLP production, it was secreted as a glycosylated protein and able to stimulate immune responses that protected mice against JEV infection [89]. Glycosylated VLPs inducing a potent immune response in mice were produced in P. pastoris for hepatitis E virus (HEV) [90]. The viral capsid is formed by the ORF2 protein harboring three glycosylation sites (Asn137, Asn310, and Asn562), with Asn310 considered the major site for glycosylation. The significance of the glycosylation of ORF2 of HEV is still not clear; however, it has been observed that mutations in the first two glycosylation sites prevent virion assembly, whereas mutation of the third site still allows virion particle formation and RNA encapsulation [91]. Gupta et al. demonstrated that the protein expressed in P. pastoris is glycosylated and can form VLPs inducing a potent immune response in mice [90].
The envelope protein prE of DENV is glycosylated. The glycosylation of this envelope protein occurs at Asn67 and has an important role in the transmission of DENV. Mutations in Asn67 glycosylation significantly suppress the replication of DENV and make the virus unable to produce new infectious particles [92]. Proper glycosylation of prE in P. pastoris has been shown for DENV-1 [93], DENV-2 [94], DENV-3 [95], and DENV-4 [96]. prE-proteins expressed in P. pastoris were glycosylated and formed VLPs inducing an immune response in mice.
In order to create P. pastoris strains with a glycosylation pattern similar to mammalian hosts, several studies of genetic modifications of P. pastoris have been performed [97]. As a result, the Pichia GlycoSwitch system has been created (https://pichia.com/glycoswitch/, accessed on 4 July 2023). The Pichia GlycoSwitch® System consists of patents, strains, and vectors that are useful for engineering P. pastoris to make proteins with several near-homogenous glycoforms. This system can be beneficial for expressing glycosylated viral proteins that are not active with glycosylation typical of yeast.

4. Hansenula polymorpha

Hansenula polymorpha (Pichia angusta) belongs to the facultative methylotrophic yeast species group. Three main H. polymorpha strains are usually used for biotechnological purposes: CBS4732, first isolated in irrigated soil in Brazil in 1959; DL-1 also, isolated in the soil in 1973, and NCYC495, first isolated in spoiled orange juice in Florida in 1951 [98]. As with P. pastoris, it can grow at higher rates than S. cerevisiae on simple and defined media, leading to highcell-density fermentation. Compared to P. pastoris, H. polymorpha is thermotolerant: the optimal growth temperature is 37–42 °C. Growth at high temperatures can both reduce the contamination risk and promote the production of proteins requiring a temperature of 37 °C to maintain their biological activity [99].
As for other yeast species, the genome of H. polymorpha has been completely sequenced and several strong promoters have been identified and characterized, including strong methanol-inducible promoters of genes such as formate dehydrogenase (pFMD), methanol oxidase (pMOX), and dihydroxyacetone synthase (pDHAS or pDAS), which control the expression of enzymes belonging to the methanol utilization pathway. The shift from glucose to methanol causes the induction of the expression of these genes and the downregulation of those belonging to the glycolytic pathway. Notably, after 2 h of growth in methanol, pFMD is 347-fold upregulated (while pDHAS is 17.3-fold) compared to glucose growth [100]. This kind of promoter can be de-repressed by glycerol and, to a lower extent, by other carbon sources, while in P. pastoris the pAOX1/2 are not de-repressed but induced by methanol. Additionally, pMOX of H. polymorpha is also induced in a medium containing both methanol and glycerol [101]. If the proteins of the viral capsomer are controlled by pFMD or pMOX, the expression can be easily controlled by changing the carbon source in the media. A methanol-inducible protein can be produced via two-step cultivation: a glycerol batch phase and a methanol/glycerol-fed batch phase (where the feed solution can be added continuously or in pulses). Adding glycerol directly in the first growing step allows us to skip the de-repression fed batch phase and to speed up the production. As for P. pastoris, the strong and constitutive glyceraldehyde-3-phosphate dehydrogenase promoter (pGAP) is used for heterologous gene expression. The pGAP has a carbon-source- and phase-dependent activity that must be considered to develop an efficient fermentation process [102].
Various genetic engineering tools and transformation protocols are well-established in H. polymorpha. The use of nanoscale carriers for DNA delivery is the most efficient method for H. polymorpha transformation [103], although other techniques are also widely used, such as the lithium acetate-dimethyl sulfoxide method [104] and electroporation (with the linearized vector) [105]. Contrary to S. cerevisiae, episomal plasmids are unstable in H. polymorpha, even when containing the H. polymorpha autonomous replicating sequences (HARS) for the autonomous replication of the circular plasmids [106]. Therefore, episomal vectors are not the most suitable solution for heterologous gene expression in H. polymorpha. Another bottleneck in the genetic manipulation of H. polymorpha is the low frequency of homologous recombination (HR) after a double-strand break (DSB); this feature limits the exploitation of homologous integration of a foreign DNA fragment. To solve this problem, a recombinant strain knocked out for the YKU80 gene, coding for a protein involved in the nonhomologous end joining (NHEJ) process after a DSB, was constructed. Consequently, this H. polymorpha yku80∆ strain has a diminished probability of random integration but maintains other physiological characteristics [107]. The H. polymorpha integration plasmids (pHIP) are the most commonly used tool for heterologous gene expression. Many pHIPs differ in terms of the selective marker and the promoter (https://www.rug.nl/research/molecular-cell-biology/research/the-hansenula-polymorpha-expression-system, accessed on 4 July 2023) [108]. Concerning post-translational modifications, N-glycans derived from H. polymorpha are similar to those of P. pastoris described in the previous paragraph and thereby are less hyper-mannosylated than the N-glycans produced by S. cerevisiae (Figure 3) [109]. VLPs composed of glycosylated proteins have been effectively produced in H. polymorpha [110,111,112]. A recombinant strain carrying a deletion in two main yeast genes belonging to hyper-mannosylation pathways, α-1,6-mannosyltransferase (Δhpoch1) and α-1,3-mannosyltransferase (Δhpalg3) was constructed in order to produce human hybrid-type N-glycans. This strain is able to express the human gene encoding β-1,2- N-acetylglucosaminyltransferase I (GnTI), an enzyme that has a key role in glycosylation [113].
In the last decade, H. polymorpha has been widely studied for VLP production, leading to interesting results which we will summarize below. Moreover, H. polymorpha-derived VLPs are already used for FDA-licensed and commercially available vaccines. Specifically, Hepavax-Gene® (Greencross Vaccine Corporation, Seoul, Republic of Korea, http://dra.gov.bt/wp-content/uploads/2016/09/Hep-B-Vaccine-SPC.pdf, accessed on 4 July 2023) and Heplisav-B® (Dynavax Technologies Corporation, Berkeley, CA, USA) https://www.fda.gov/vaccines-blood-biologics/vaccines/heplisav-b (accessed on 4 July 2023) are commercially available vaccines for HBV.
Most common commercially available HBV vaccines are composed of the antigen HBsAg, but it has been demonstrated that the medium envelope protein PresS2-S can elicit a neutralizing response. Consequently, Xu et. al., expressed a codon-optimized truncated form of PreS2-S (26 amino acids of PreS2 C-terminus) fused to the N-terminus of HBsAg in H. polymorpha, under the control of pMOX in an integration plasmid, resulting in stable multiple copy insertions (an average of 60 copies). PreS2-S accumulated intracellularly, and was purified by cell disruption. They obtained morphologically uniform particles with ~99% of purity, more than that obtained with P. pastoris [114,115].
More recently, Wetzel et. al., used H. polymorpha to produce chimeric VLPs presenting four antigens from animal-infectious viruses. In particular, the membrane small surface protein (dS) of duck hepatitis B (DHBV) was selected as a scaffold for VLPs containing antigens derived from four animal-infecting viruses. The antigens were genetically fused to the dS and expressed under the control of pMOX of a stable genomic integrated plasmid. Chimeric VLPs with 95% purity and containing up to 33% of the fusion protein were obtained with a production efficiency of 40 mg of VLPs per 100 g of dry cell weight [116]. The same platform was used to develop three different types of chimeric VLPs, each displaying a different foreign antigen derived from P. falciparum [112].
Interestingly, H. polymorpha has successfully produced two-component human parvovirus B19 VLP with proteins in a different stoichiometry. The capsid of B19 is composed of two types of protein, the major capsid protein VP2 and the minor protein VP1. Specifically, VP1 and VP2 were co-expressed in H. polymorpha from two plasmids where they were cloned under the control of pMOX. Furthermore, another methanol-inducible expression promoter (pDAS) was adopted to improve the relative proportion of VP1 in the VLPs. Thereby, the authors produced two types of VLPs—the VLP with equally assembled VP1 and VP2 (VP1/VP2 VLP), and the VLP with an improved VP1 content (VP1h/VP2 VLP)—and demonstrated that VLPs with an increased VP1 content elicit a higher level of neutralizing antibodies against B19 than VP1/VP2 VLP [117]. As for the other yeast species, the bottleneck in producing VLPs is the purification method because viral proteins accumulate intracellularly [118]. H. polymorpha can be engineered to modulate the ER folding environment and, therefore, to secrete a heterologous protein [119]. The purpose of the study was to produce a recombinant truncated G protein (a glycoprotein generally localized in the envelope of the Rabies virus) to use it as a coating antigen in ELISAs and thus obtain an inexpensive diagnostic tool. They expressed the protein in a H. polymorpha strain overexpressing calnexin, a key component of the quality control mechanism in the ER, shown to enhance the secretion of all types of heterologous protein [120]. A heterologous protein’s secretion has also been performed with the leader sequence of the α-factor [102]. However, secretion approaches must be further characterized, and these results could inspire further studies for the set-up of engineered H. polymorpha that can secrete the viral proteins for VLP assembly in the growth medium.

5. Comparison of VLP Production in the Three Yeast Species

In order to establish which is the best yeast to choose for developing a new VLP product, it is not easy to compare results reported in different publications. In most cases, VLPs produced in other yeast species can be composed of the same viral proteins, but also of different viral proteins. For instance, HEV VLPs, composed of the same viral protein, were produced in the three yeast species, with the only difference being that in P. pastoris were secreted; thus, the purification protocol was more straightforward than that used in other systems. Moreover, VLPs composed of different viral proteins have successfully been produced in S. cerevisiae and P. pastoris (Table 4).
Some studies have focused on the comparison between yeast strains and E. coli. A yeast-derived VLP composed of recombinant bacteriophage Qβ coat protein (CP) was found to be as immunogenic as that produced in E. coli. Moreover, Qβ-VLP assembled in S. cerevisiae and P. pastoris were about 15–20% and 20–30% of the E. coli expression level, respectively [161]. The same group investigated the possibility of producing VLPs composed of other bacteriophages’ CP proteins in yeast S. cerevisiae and P. pastoris. They compared the expression levels in S. cerevisiae and P. pastoris using episomal and integrative vectors, respectively. They observed that the amount of target protein varied significantly between strains. Specifically, efficient P. pastoris producer strains were selected for phage PP7 and φCb5 CPs; slightly better production of CP phages fr and SP was observed in S. cerevisiae. The solubility of most CP proteins was comparable in the two systems with exception of phage SP CP, which was completely insoluble when expressed in S. cerevisiae and partially soluble in P. pastoris. In another study, the expression level of rotavirus VP6 protein in P. pastoris and H. polymorpha was compared with that reached in E. coli. Codon optimized VP6 was expressed intracellularly under the control of methanol-inducible promoter. Results indicated that the highest VP6 concentration was obtained with E. coli; however, the expressed protein was found to be insoluble and consequently difficult to purify. On the other hand, in shake flasks, specific production of VP6 was approximately similar in both yeasts. The authors concluded that, when growing yeast cells in bioreactors, H. polymorpha outperforms both P. pastoris and E. coli [162]. In a recent study, P. pastoris and H. polymorpha were used to assemble VLPs of HPV. The level of L1 protein, expressed under the control of a methanol-inducible promoter, and production efficiency were both higher in P. pastoris than in H. polymorpha [163].
Overall, these studies suggest that performing VLP expression simultaneously in at least two species could facilitate identifying the best production platform. These studies also confirm that yeast can be a valuable tool in the production of VLPs to be used as antigens for vaccine development. Moreover, yeasts could be a potentially valuable system to generate VLPs to be used as a carrier for drug delivery, a strategy so far poorly explored [22,83]. It is a matter of setting up the best conditions. So far, these kinds of particles are mainly produced in E. coli and higher eukaryote platforms and are often assembled “in vitro”.
The key question is what yeast species might be the best to produce VLPs. In Figure 4, we compare the key features to consider when planning a platform for VLP production for the three species. H. polymorpha has the advantage of growing at 37 °C, a condition that can be crucial for correct protein folding. On the other hand, secretion, which is important to facilitate purification, has been poorly investigated in H. polymorpha, so further studies are necessary to exploit this feature in this species.

6. Conclusions

The SARS-CoV-2 outbreak highlighted the need to increase our knowledge of the vaccine production platform in response to the spread of the emerging virus. The yeast expression system has the same advantages as bacteria, in terms of growth rate and costs, and mammalian cells, because the proteins produced are safe and correctly folded.
So far, twenty-nine VLP-based vaccines have reached the market or have progressed to clinical trials [16]. Among them, ten were produced in yeast. In this analysis, we did not consider a VLP-based vaccine against HIV since it did not pass phase I clinical trial because it could not induce a significant humoral and cellular immune response [164,165]. Nine vaccines were produced in insect cells, six in bacteria, and only one in mammalian cells. Interestingly, eight out of nine yeast-based VLP vaccines were approved by the FDA for commercial use, suggesting that safety and costs have a high impact on the selection of the platform for VLP production.
In conclusion, the following aspects should be considered to set up a yeast-based VLP platform:
  • The number of proteins to be expressed. Some proteins must be in a suitable ratio to assemble in functional VLPs;
  • Primary assessment of heterologous protein expression. The evaluation of the effect of the protein is crucial; toxicity should be avoided; therefore, several mutants (protease deficient, high temperature tolerant, secretory efficient) should be considered;
  • Inducible promoters and episomal plasmids are preferable; usually, high efficiency of DNA transformation is required. For this reason, S. cerevisiae and P. pastoris strains could be more suitable;
  • Plasmid stability. In general, in S. cerevisiae and P. pastoris, episomal or centromeric plasmids are more stable than in H. polymorpha. In H. polymorpha, plasmids must be integrated into the genome to achieve high stability. Therefore, if the expression of the heterologous proteins confers toxicity when expressed in high copy number, the use of H. polymorpha expression system which consists of one single stable integrated copy of the gene is preferable.
The rationale behind the choice of the production strategy depends on the endpoint application of VLPs and yeast strains thanks to the available tools; its flexibility can be tailored to the type of VLPs. Therefore, we can conclude that VLPs, especially non-enveloped VLPs, and yeast are a “perfect couple”.

Author Contributions

Conceptualization: T.C., T.C., S.B. and A.G.; writing—original draft preparation: T.C., S.B. and A.G. reviewed the final draft and approved submission. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

Not applicable.

Acknowledgments

We thank Filippo Cipriani for critical reading and language editing.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Fraenkel-Conrat, H.; Williams, R.C. Reconstitution of Active Tobacco Mosaic Virus from Its Inactive Protein and Nucleic Acid Components. Proc. Natl. Acad. Sci. USA 1955, 41, 690–698. [Google Scholar] [CrossRef]
  2. Bayer, M.E.; Blumberg, B.S.; Werner, B. Particles associated with Australia antigen in the sera of patients with leukaemia, Down’s Syndrome and hepatitis. Nature 1968, 218, 1057–1059. [Google Scholar] [CrossRef] [PubMed]
  3. Klucis, E.; Jackson, L.; Parsons, P.G. Survey of human lymphoblastoid cell lines and primary cultures of normal and leukaemic leukocytes for oncornavirus production. Int. J. Cancer 1976, 18, 413–420. [Google Scholar] [CrossRef] [PubMed]
  4. Graves, D.C.; Ferrer, J.F. In vitro transmission and propagation of the bovine leukemia virus in monolayer cell cultures. Cancer Res. 1976, 36, 4152–4159. [Google Scholar] [PubMed]
  5. Engelberg-Kulka, H.; Dekel, L.; Israeli-Reches, M. Streptomycin-resistant Escherichia coli mutant temperature sensitive for the production of Qbeta-infective particles. J. Virol. 1977, 21, 1–6. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  6. Volkoff, O.; Walters, T. Virus-like particles in abnormal cells of Saccharomyces carlsbergensis. Can. J. Genet. Cytol. 1970, 12, 621–626. [Google Scholar] [CrossRef]
  7. Berry, E.A.; Bevan, E.A. A new species of double-stranded RNA from yeast. Nature 1972, 239, 279–280. [Google Scholar] [CrossRef]
  8. Bevan, E.A.; Herring, A.J.; Mitchell, D.J. Preliminary characterization of two species of dsRNA in yeast and their relationship to the “killer” character. Nature 1973, 245, 81–86. [Google Scholar] [CrossRef]
  9. Wood, H.A. Viruses with double-stranded RNA genomes. J. Gen. Virol. 1973, 20, 61–85. [Google Scholar] [CrossRef]
  10. Bruenn, J.A. Virus-like particles of yeast. Annu. Rev. Microbiol. 1980, 34, 49–68. [Google Scholar] [CrossRef]
  11. Wickner, R.B. Double-stranded and single-stranded RNA viruses of Saccharomyces cerevisiae. Annu. Rev. Microbiol. 1992, 46, 347–375. [Google Scholar] [CrossRef] [PubMed]
  12. Mason, H.S.; Lam, D.M.; Arntzen, C.J. Expression of hepatitis B surface antigen in transgenic plants. Proc. Natl. Acad. Sci. USA 1992, 89, 11745–11749. [Google Scholar] [CrossRef] [PubMed]
  13. Chung, Y.H.; Church, D.; Koellhoffer, E.C.; Osota, E.; Shukla, S.; Rybicki, E.P.; Pokorski, J.K.; Steinmetz, N.F. Integrating plant molecular farming and materials research for next-generation vaccines. Nat. Rev. Mater. 2022, 7, 372–388. [Google Scholar] [CrossRef] [PubMed]
  14. Croizier, L.; Jousset, F.X.; Veyrunes, J.C.; Lopez-Ferber, M.; Bergoin, M.; Croizier, G. Protein requirements for assembly of virus-like particles of Junonia coenia densovirus in insect cells. J. Gen. Virol. 2000, 81, 1605–1613. [Google Scholar] [CrossRef]
  15. Tariq, H.; Batool, S.; Asif, S.; Ali, M.; Abbasi, B.H. Virus-Like Particles: Revolutionary Platforms for Developing Vaccines Against Emerging Infectious Diseases. Front. Microbiol. 2021, 12, 790121. [Google Scholar] [CrossRef]
  16. Qian, C.; Liu, X.; Xu, Q.; Wang, Z.; Chen, J.; Li, T.; Zheng, Q.; Yu, H.; Gu, Y.; Li, S.; et al. Recent Progress on the Versatility of Virus-Like Particles. Vaccines 2020, 8, 139. [Google Scholar] [CrossRef] [Green Version]
  17. Ward, B.J.; Makarkov, A.; Seguin, A.; Pillet, S.; Trepanier, S.; Dhaliwall, J.; Libman, M.D.; Vesikari, T.; Landry, N. Efficacy, immunogenicity, and safety of a plant-derived, quadrivalent, virus-like particle influenza vaccine in adults (18–64 years) and older adults (>/=65 years): Two multicentre, randomised phase 3 trials. Lancet 2020, 396, 1491–1503. [Google Scholar] [CrossRef]
  18. Palucha, A.; Loniewska, A.; Satheshkumar, S.; Boguszewska-Chachulska, A.M.; Umashankar, M.; Milner, M.; Haenni, A.L.; Savithri, H.S. Virus-like particles: Models for assembly studies and foreign epitope carriers. Prog. Nucleic Acid. Res. Mol. Biol. 2005, 80, 135–168. [Google Scholar] [CrossRef]
  19. Ikwuagwu, B.; Tullman-Ercek, D. Virus-like particles for drug delivery: A review of methods and applications. Curr. Opin. Biotechnol. 2022, 78, 102785. [Google Scholar] [CrossRef]
  20. Nooraei, S.; Bahrulolum, H.; Hoseini, Z.S.; Katalani, C.; Hajizade, A.; Easton, A.J.; Ahmadian, G. Virus-like particles: Preparation, immunogenicity and their roles as nanovaccines and drug nanocarriers. J. Nanobiotechnol. 2021, 19, 59. [Google Scholar] [CrossRef]
  21. Tornesello, A.L.; Tagliamonte, M.; Buonaguro, F.M.; Tornesello, M.L.; Buonaguro, L. Virus-like Particles as Preventive and Therapeutic Cancer Vaccines. Vaccines 2022, 10, 227. [Google Scholar] [CrossRef] [PubMed]
  22. Yamada, T.; Iwasaki, Y.; Tada, H.; Iwabuki, H.; Chuah, M.K.; VandenDriessche, T.; Fukuda, H.; Kondo, A.; Ueda, M.; Seno, M.; et al. Nanoparticles for the delivery of genes and drugs to human hepatocytes. Nat. Biotechnol. 2003, 21, 885–890. [Google Scholar] [CrossRef]
  23. Li, Y.; Liu, D.; Wang, Y.; Su, W.; Liu, G.; Dong, W. The Importance of Glycans of Viral and Host Proteins in Enveloped Virus Infection. Front. Immunol. 2021, 12, 638573. [Google Scholar] [CrossRef] [PubMed]
  24. Coombs, K.M. Stoichiometry of reovirus structural proteins in virus, ISVP, and core particles. Virology 1998, 243, 218–228. [Google Scholar] [CrossRef] [Green Version]
  25. Weitzman, M.D.; Linden, R.M. Adeno-associated virus biology. Methods Mol. Biol. 2011, 807, 1–23. [Google Scholar] [CrossRef] [PubMed]
  26. Byrne, L.J.; O’Callaghan, K.J.; Tuite, M.F. Heterologous gene expression in yeast. Methods Mol. Biol. 2005, 308, 51–64. [Google Scholar] [CrossRef]
  27. Vieira Gomes, A.M.; Souza Carmo, T.; Silva Carvalho, L.; Mendonca Bahia, F.; Parachin, N.S. Comparison of Yeasts as Hosts for Recombinant Protein Production. Microorganisms 2018, 29, 38. [Google Scholar] [CrossRef] [Green Version]
  28. Kumar, R.; Kumar, P. Yeast-based vaccines: New perspective in vaccine development and application. FEMS Yeast Res. 2019, 19, foz007. [Google Scholar] [CrossRef] [Green Version]
  29. Bill, R.M. Recombinant protein subunit vaccine synthesis in microbes: A role for yeast? J. Pharm. Pharmacol. 2015, 67, 319–328. [Google Scholar] [CrossRef] [Green Version]
  30. Srivastava, V.; Nand, K.N.; Ahmad, A.; Kumar, R. Yeast-Based Virus-like Particles as an Emerging Platform for Vaccine Development and Delivery. Vaccines 2023, 11, 479. [Google Scholar] [CrossRef]
  31. Gassler, T.; Heistinger, L.; Mattanovich, D.; Gasser, B.; Prielhofer, R. CRISPR/Cas9-Mediated Homology-Directed Genome Editing in Pichia pastoris. Methods Mol. Biol. 2019, 1923, 211–225. [Google Scholar] [CrossRef] [PubMed]
  32. Laughery, M.F.; Wyrick, J.J. Simple CRISPR-Cas9 Genome Editing in Saccharomyces cerevisiae. Curr. Protoc. Mol. Biol. 2019, 129, e110. [Google Scholar] [CrossRef] [PubMed]
  33. Numamoto, M.; Maekawa, H.; Kaneko, Y. Efficient genome editing by CRISPR/Cas9 with a tRNA-sgRNA fusion in the methylotrophic yeast Ogataea polymorpha. J. Biosci. Bioeng. 2017, 124, 487–492. [Google Scholar] [CrossRef] [PubMed]
  34. Madhavan, A.; Arun, K.B.; Sindhu, R.; Krishnamoorthy, J.; Reshmy, R.; Sirohi, R.; Pugazhendi, A.; Awasthi, M.K.; Szakacs, G.; Binod, P. Customized yeast cell factories for biopharmaceuticals: From cell engineering to process scale up. Microb. Cell Fact. 2021, 20, 124. [Google Scholar] [CrossRef] [PubMed]
  35. Gnugge, R.; Rudolf, F. Saccharomyces cerevisiae Shuttle vectors. Yeast 2017, 34, 205–221. [Google Scholar] [CrossRef] [Green Version]
  36. Sun, J.; Shao, Z.; Zhao, H.; Nair, N.; Wen, F.; Xu, J.H. Cloning and characterization of a panel of constitutive promoters for applications in pathway engineering in Saccharomyces cerevisiae. Biotechnol. Bioeng. 2012, 109, 2082–2092. [Google Scholar] [CrossRef]
  37. Weinhandl, K.; Winkler, M.; Glieder, A.; Camattari, A. Carbon source dependent promoters in yeasts. Microb. Cell Fact. 2014, 13, 5. [Google Scholar] [CrossRef] [Green Version]
  38. Partow, S.; Siewers, V.; Bjorn, S.; Nielsen, J.; Maury, J. Characterization of different promoters for designing a new expression vector in Saccharomyces cerevisiae. Yeast 2010, 27, 955–964. [Google Scholar] [CrossRef]
  39. West, R.W., Jr.; Chen, S.M.; Putz, H.; Butler, G.; Banerjee, M. GAL1-GAL10 divergent promoter region of Saccharomyces cerevisiae contains negative control elements in addition to functionally separate and possibly overlapping upstream activating sequences. Genes. Dev. 1987, 1, 1118–1131. [Google Scholar] [CrossRef] [Green Version]
  40. Butt, T.R.; Ecker, D.J. Yeast metallothionein and applications in biotechnology. Microbiol. Rev. 1987, 51, 351–364. [Google Scholar] [CrossRef]
  41. Hauf, J.; Zimmermann, F.K.; Muller, S. Simultaneous genomic overexpression of seven glycolytic enzymes in the yeast Saccharomyces cerevisiae. Enzyme Microb. Technol. 2000, 26, 688–698. [Google Scholar] [CrossRef] [PubMed]
  42. Lee, K.M.; DaSilva, N.A. Evaluation of the Saccharomyces cerevisiae ADH2 promoter for protein synthesis. Yeast 2005, 22, 431–440. [Google Scholar] [CrossRef] [PubMed]
  43. Yang, J.; Tian, Y.; Liu, H.; Kan, Y.; Zhou, Y.; Wang, Y.; Luo, Y. Harnessing the Endogenous 2mu Plasmid of Saccharomyces cerevisiae for Pathway Construction. Front. Microbiol. 2021, 12, 679665. [Google Scholar] [CrossRef]
  44. Valenzuela, P.; Medina, A.; Rutter, W.J.; Ammerer, G.; Hall, B.D. Synthesis and assembly of hepatitis B virus surface antigen particles in yeast. Nature 1982, 298, 347–350. [Google Scholar] [CrossRef]
  45. Hofmann, K.J.; Cook, J.C.; Joyce, J.G.; Brown, D.R.; Schultz, L.D.; George, H.A.; Rosolowsky, M.; Fife, K.H.; Jansen, K.U. Sequence determination of human papillomavirus type 6a and assembly of virus-like particles in Saccharomyces cerevisiae. Virology 1995, 209, 506–518. [Google Scholar] [CrossRef]
  46. Sapp, M.; Volpers, C.; Streeck, R.E. Synthesis, properties and applications of papillomavirus-like particles. Intervirology 1996, 39, 49–53. [Google Scholar] [CrossRef]
  47. Sasnauskas, K.; Bulavaite, A.; Hale, A.; Jin, L.; Knowles, W.A.; Gedvilaite, A.; Dargeviciute, A.; Bartkeviciute, D.; Zvirbliene, A.; Staniulis, J.; et al. Generation of recombinant virus-like particles of human and non-human polyomaviruses in yeast Saccharomyces cerevisiae. Intervirology 2002, 45, 308–317. [Google Scholar] [CrossRef]
  48. Zeltins, A. Construction and characterization of virus-like particles: A review. Mol. Biotechnol. 2013, 53, 92–107. [Google Scholar] [CrossRef]
  49. Kim, H.J.; Kim, H.J. Yeast as an expression system for producing virus-like particles: What factors do we need to consider? Lett. Appl. Microbiol. 2017, 64, 111–123. [Google Scholar] [CrossRef]
  50. Sakuragi, S.; Goto, T.; Sano, K.; Morikawa, Y. HIV type 1 Gag virus-like particle budding from spheroplasts of Saccharomyces cerevisiae. Proc. Natl. Acad. Sci. USA 2002, 99, 7956–7961. [Google Scholar] [CrossRef]
  51. Mazumder, S.; Rastogi, R.; Undale, A.; Arora, K.; Arora, N.M.; Pratim, B.; Kumar, D.; Joseph, A.; Mali, B.; Arya, V.B.; et al. PRAK-03202: A triple antigen virus-like particle vaccine candidate against SARS CoV-2. Heliyon 2021, 7, e08124. [Google Scholar] [CrossRef] [PubMed]
  52. Backovic, A.; Cervelli, T.; Salvetti, A.; Zentilin, L.; Giacca, M.; Galli, A. Capsid protein expression and adeno-associated virus like particles assembly in Saccharomyces cerevisiae. Microb. Cell Fact. 2012, 11, 124. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  53. Barajas, D.; Aponte-Ubillus, J.J.; Akeefe, H.; Cinek, T.; Peltier, J.; Gold, D. Generation of infectious recombinant Adeno-associated virus in Saccharomyces cerevisiae. PLoS ONE 2017, 12, e0173010. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  54. Muller, S.; Sandal, T.; Kamp-Hansen, P.; Dalboge, H. Comparison of expression systems in the yeasts Saccharomyces cerevisiae, Hansenula polymorpha, Klyveromyces lactis, Schizosaccharomyces pombe and Yarrowia lipolytica. Cloning of two novel promoters from Yarrowia lipolytica. Yeast 1998, 14, 1267–1283. [Google Scholar] [CrossRef]
  55. Tran, A.M.; Nguyen, T.T.; Nguyen, C.T.; Huynh-Thi, X.M.; Trinh, M.T.; Tran, L.T.; Cartwright, S.P.; Bill, R.M.; Tran-Van, H. Pichia pastoris versus Saccharomyces cerevisiae: A case study on the recombinant production of human granulocyte-macrophage colony-stimulating factor. BMC Res. Notes 2017, 10, 148. [Google Scholar] [CrossRef] [Green Version]
  56. Huang, M.; Wang, G.; Qin, J.; Petranovic, D.; Nielsen, J. Engineering the protein secretory pathway of Saccharomyces cerevisiae enables improved protein production. Proc. Natl. Acad. Sci. USA 2018, 115, E11025–E11032. [Google Scholar] [CrossRef] [Green Version]
  57. Turcotte, B.; Liang, X.B.; Robert, F.; Soontorngun, N. Transcriptional regulation of nonfermentable carbon utilization in budding yeast. FEMS Yeast Res. 2010, 10, 2–13. [Google Scholar] [CrossRef] [Green Version]
  58. Gerngross, T. Production of complex human glycoproteins in yeast. Adv. Exp. Med. Biol. 2005, 564, 139. [Google Scholar] [CrossRef] [Green Version]
  59. Hamilton, S.R.; Bobrowicz, P.; Bobrowicz, B.; Davidson, R.C.; Li, H.; Mitchell, T.; Nett, J.H.; Rausch, S.; Stadheim, T.A.; Wischnewski, H.; et al. Production of complex human glycoproteins in yeast. Science 2003, 301, 1244–1246. [Google Scholar] [CrossRef]
  60. Lee, H.; DeLoache, W.C.; Dueber, J.E. Spatial organization of enzymes for metabolic engineering. Metab. Eng. 2012, 14, 242–251. [Google Scholar] [CrossRef]
  61. Cheah, L.C.; Stark, T.; Adamson, L.S.R.; Abidin, R.S.; Lau, Y.H.; Sainsbury, F.; Vickers, C.E. Artificial Self-assembling Nanocompartment for Organizing Metabolic Pathways in Yeast. ACS Synth. Biol. 2021, 10, 3251–3263. [Google Scholar] [CrossRef] [PubMed]
  62. Malci, K.; Watts, E.; Roberts, T.M.; Auxillos, J.Y.; Nowrouzi, B.; Boll, H.O.; Nascimento, C.; Andreou, A.; Vegh, P.; Donovan, S.; et al. Standardization of Synthetic Biology Tools and Assembly Methods for Saccharomyces cerevisiae and Emerging Yeast Species. ACS Synth. Biol. 2022, 11, 2527–2547. [Google Scholar] [CrossRef] [PubMed]
  63. Buckholz, R.G.; Gleeson, M.A. Yeast systems for the commercial production of heterologous proteins. Biotechnology 1991, 9, 1067–1072. [Google Scholar] [CrossRef]
  64. Sturmberger, L.; Chappell, T.; Geier, M.; Krainer, F.; Day, K.J.; Vide, U.; Trstenjak, S.; Schiefer, A.; Richardson, T.; Soriaga, L.; et al. Refined Pichia pastoris reference genome sequence. J. Biotechnol. 2016, 235, 121–131. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  65. Cereghino, J.L.; Cregg, J.M. Heterologous protein expression in the methylotrophic yeast Pichia pastoris. FEMS Microbiol. Rev. 2000, 24, 45–66. [Google Scholar] [CrossRef] [PubMed]
  66. Karbalaei, M.; Rezaee, S.A.; Farsiani, H. Pichia pastoris: A highly successful expression system for optimal synthesis of heterologous proteins. J. Cell. Physiol. 2020, 235, 5867–5881. [Google Scholar] [CrossRef] [PubMed]
  67. Shukla, R.; Rajpoot, R.K.; Arora, U.; Poddar, A.; Swaminathan, S.; Khanna, N. Pichia pastoris-Expressed Bivalent Virus-Like Particulate Vaccine Induces Domain III-Focused Bivalent Neutralizing Antibodies without Antibody-Dependent Enhancement in Vivo. Front. Microbiol. 2017, 8, 2644. [Google Scholar] [CrossRef] [Green Version]
  68. Liu, W.; Jiang, H.; Zhou, J.; Yang, X.; Tang, Y.; Fang, D.; Jiang, L. Recombinant dengue virus-like particles from Pichia pastoris: Efficient production and immunological properties. Virus Genes 2010, 40, 53–59. [Google Scholar] [CrossRef]
  69. Tang, Y.X.; Jiang, L.F.; Zhou, J.M.; Yin, Y.; Yang, X.M.; Liu, W.Q.; Fang, D.Y. Induction of virus-neutralizing antibodies and T cell responses by dengue virus type 1 virus-like particles prepared from Pichia pastoris. Chin. Med. J. 2012, 125, 1986–1992. [Google Scholar]
  70. Vogl, T.; Hartner, F.S.; Glieder, A. New opportunities by synthetic biology for biopharmaceutical production in Pichia pastoris. Curr. Opin. Biotechnol. 2013, 24, 1094–1101. [Google Scholar] [CrossRef] [Green Version]
  71. Garrigos-Martinez, J.; Vuoristo, K.; Nieto-Taype, M.A.; Tahtiharju, J.; Uusitalo, J.; Tukiainen, P.; Schmid, C.; Tolstorukov, I.; Madden, K.; Penttila, M.; et al. Bioprocess performance analysis of novel methanol-independent promoters for recombinant protein production with Pichia pastoris. Microb. Cell Fact. 2021, 20, 74. [Google Scholar] [CrossRef] [PubMed]
  72. Qin, X.; Qian, J.; Yao, G.; Zhuang, Y.; Zhang, S.; Chu, J. GAP promoter library for fine-tuning of gene expression in Pichia pastoris. Appl. Environ. Microbiol. 2011, 77, 3600–3608. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  73. Liu, Y.; Zhou, J.; Yu, Z.; Fang, D.; Fu, C.; Zhu, X.; He, Z.; Yan, H.; Jiang, L. Tetravalent recombinant dengue virus-like particles as potential vaccine candidates: Immunological properties. BMC Microbiol. 2014, 14, 233. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  74. Feng, Q.; He, Y.; Lu, J. Virus-Like Particles Produced in Pichia pastoris Induce Protective Immune Responses against Coxsackievirus A16 in Mice. Med. Sci. Monit. 2016, 22, 3370–3382. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  75. Eto, Y.; Saubi, N.; Ferrer, P.; Joseph-Munne, J. Expression of Chimeric HPV-HIV Protein L1P18 in Pichia pastoris; Purification and Characterization of the Virus-like Particles. Pharmaceutics 2021, 13, 1967. [Google Scholar] [CrossRef]
  76. Delic, M.; Valli, M.; Graf, A.B.; Pfeffer, M.; Mattanovich, D.; Gasser, B. The secretory pathway: Exploring yeast diversity. FEMS Microbiol. Rev. 2013, 37, 872–914. [Google Scholar] [CrossRef] [Green Version]
  77. Chahal, S.; Wei, P.; Moua, P.; Park, S.P.; Kwon, J.; Patel, A.; Vu, A.T.; Catolico, J.A.; Tsai, Y.F.; Shaheen, N.; et al. Structural characterization of the alpha-mating factor prepro-peptide for secretion of recombinant proteins in Pichia pastoris. Gene 2017, 598, 50–62. [Google Scholar] [CrossRef]
  78. Barrero, J.J.; Casler, J.C.; Valero, F.; Ferrer, P.; Glick, B.S. An improved secretion signal enhances the secretion of model proteins from Pichia pastoris. Microb. Cell Fact. 2018, 17, 161. [Google Scholar] [CrossRef]
  79. Duan, G.; Ding, L.; Wei, D.; Zhou, H.; Chu, J.; Zhang, S.; Qian, J. Screening endogenous signal peptides and protein folding factors to promote the secretory expression of heterologous proteins in Pichia pastoris. J. Biotechnol. 2019, 306, 193–202. [Google Scholar] [CrossRef]
  80. Obst, U.; Lu, T.K.; Sieber, V. A Modular Toolkit for Generating Pichia pastoris Secretion Libraries. ACS Synth. Biol. 2017, 6, 1016–1025. [Google Scholar] [CrossRef]
  81. Raschmanova, H.; Weninger, A.; Knejzlik, Z.; Melzoch, K.; Kovar, K. Engineering of the unfolded protein response pathway in Pichia pastoris: Enhancing production of secreted recombinant proteins. Appl. Microbiol. Biotechnol. 2021, 105, 4397–4414. [Google Scholar] [CrossRef] [PubMed]
  82. Tome-Amat, J.; Fleischer, L.; Parker, S.A.; Bardliving, C.L.; Batt, C.A. Secreted production of assembled Norovirus virus-like particles from Pichia pastoris. Microb. Cell Fact. 2014, 13, 134. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  83. Zhu, J.; Yang, K.; Liu, A.; Lu, X.; Yang, L.; Zhao, Q. Highly secretory expression of recombinant cowpea chlorotic mottle virus capsid proteins in Pichia pastoris and in-vitro encapsulation of ruthenium nanoparticles for catalysis. Protein Expr. Purif. 2020, 174, 105679. [Google Scholar] [CrossRef] [PubMed]
  84. Yun, S.M.; Jeong, Y.E.; Wang, E.; Lee, Y.J.; Han, M.G.; Park, C.; Lee, W.J.; Choi, W. Cloning and Expression of Recombinant Tick-Borne Encephalitis Virus-like Particles in Pichia pastoris. Osong Public Health Res. Perspect. 2014, 5, 274–278. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  85. Bazan, S.B.; de Alencar Muniz Chaves, A.; Aires, K.A.; Cianciarullo, A.M.; Garcea, R.L.; Ho, P.L. Expression and characterization of HPV-16 L1 capsid protein in Pichia pastoris. Arch. Virol. 2009, 154, 1609–1617. [Google Scholar] [CrossRef] [Green Version]
  86. Mariz, F.C.; Coimbra, E.C.; Jesus, A.L.; Nascimento, L.M.; Torres, F.A.; Freitas, A.C. Development of an IP-Free Biotechnology Platform for Constitutive Production of HPV16 L1 Capsid Protein Using the Pichia pastoris PGK1 Promoter. Biomed. Res. Int. 2015, 2015, 594120. [Google Scholar] [CrossRef] [Green Version]
  87. Saraswat, S.; Athmaram, T.N.; Parida, M.; Agarwal, A.; Saha, A.; Dash, P.K. Expression and Characterization of Yeast Derived Chikungunya Virus Like Particles (CHIK-VLPs) and Its Evaluation as a Potential Vaccine Candidate. PLoS Negl. Trop. Dis. 2016, 10, e0004782. [Google Scholar] [CrossRef] [Green Version]
  88. Kim, H.S.; Jeon, J.H.; Lee, K.J.; Ko, K. N-glycosylation modification of plant-derived virus-like particles: An application in vaccines. Biomed. Res. Int. 2014, 2014, 249519. [Google Scholar] [CrossRef] [Green Version]
  89. Kwon, W.T.; Lee, W.S.; Park, P.J.; Park, T.K.; Kang, H. Protective immunity of Pichia pastoris-expressed recombinant envelope protein of Japanese encephalitis virus. J. Microbiol. Biotechnol. 2012, 22, 1580–1587. [Google Scholar] [CrossRef]
  90. Gupta, J.; Kaul, S.; Srivastava, A.; Kaushik, N.; Ghosh, S.; Sharma, C.; Batra, G.; Banerjee, M.; Shalimar; Nayak, B.; et al. Expression, Purification and Characterization of the Hepatitis E Virus Like-Particles in the Pichia pastoris. Front. Microbiol. 2020, 11, 141. [Google Scholar] [CrossRef] [Green Version]
  91. Zhou, Z.; Xie, Y.; Wu, C.; Nan, Y. The Hepatitis E Virus Open Reading Frame 2 Protein: Beyond Viral Capsid. Front. Microbiol. 2021, 12, 739124. [Google Scholar] [CrossRef] [PubMed]
  92. Feng, T.; Zhang, J.; Chen, Z.; Pan, W.; Yan, Y.; Dai, J. Glycosylation of viral proteins: Implication in virus-host interaction and virulence. Virulence 2022, 13, 670–683. [Google Scholar] [CrossRef] [PubMed]
  93. Poddar, A.; Ramasamy, V.; Shukla, R.; Rajpoot, R.K.; Arora, U.; Jain, S.K.; Swaminathan, S.; Khanna, N. Virus-like particles derived from Pichia pastoris-expressed dengue virus type 1 glycoprotein elicit homotypic virus-neutralizing envelope domain III-directed antibodies. BMC Biotechnol. 2016, 16, 50. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  94. Mani, S.; Tripathi, L.; Raut, R.; Tyagi, P.; Arora, U.; Barman, T.; Sood, R.; Galav, A.; Wahala, W.; de Silva, A.; et al. Pichia pastoris-expressed dengue 2 envelope forms virus-like particles without pre-membrane protein and induces high titer neutralizing antibodies. PLoS ONE 2013, 8, e64595. [Google Scholar] [CrossRef] [PubMed]
  95. Tripathi, L.; Mani, S.; Raut, R.; Poddar, A.; Tyagi, P.; Arora, U.; de Silva, A.; Swaminathan, S.; Khanna, N. Pichia pastoris-expressed dengue 3 envelope-based virus-like particles elicit predominantly domain III-focused high titer neutralizing antibodies. Front. Microbiol. 2015, 6, 1005. [Google Scholar] [CrossRef] [Green Version]
  96. Khetarpal, N.; Shukla, R.; Rajpoot, R.K.; Poddar, A.; Pal, M.; Swaminathan, S.; Arora, U.; Khanna, N. Recombinant Dengue Virus 4 Envelope Glycoprotein Virus-Like Particles Derived from Pichia pastoris are Capable of Eliciting Homotypic Domain III-Directed Neutralizing Antibodies. Am. J. Trop. Med. Hyg. 2017, 96, 126–134. [Google Scholar] [CrossRef] [Green Version]
  97. Hamilton, S.R.; Davidson, R.C.; Sethuraman, N.; Nett, J.H.; Jiang, Y.; Rios, S.; Bobrowicz, P.; Stadheim, T.A.; Li, H.; Choi, B.K.; et al. Humanization of yeast to produce complex terminally sialylated glycoproteins. Science 2006, 313, 1441–1443. [Google Scholar] [CrossRef] [Green Version]
  98. Satyanarayana, G.K. (Ed.) Yeast Biotechnology: Diversity and Applications; Springer: Dordrecht, The Netherlands, 2009. [Google Scholar]
  99. Manfrao-Netto, J.H.C.; Gomes, A.M.V.; Parachin, N.S. Advances in Using Hansenula polymorpha as Chassis for Recombinant Protein Production. Front. Bioeng. Biotechnol. 2019, 7, 94. [Google Scholar] [CrossRef]
  100. Van Zutphen, T.; Baerends, R.J.; Susanna, K.A.; de Jong, A.; Kuipers, O.P.; Veenhuis, M.; van der Klei, I.J. Adaptation of Hansenula polymorpha to methanol: A transcriptome analysis. BMC Genom. 2010, 11, 1. [Google Scholar] [CrossRef] [Green Version]
  101. Hartner, F.S.; Glieder, A. Regulation of methanol utilisation pathway genes in yeasts. Microb. Cell Fact. 2006, 5, 39. [Google Scholar] [CrossRef] [Green Version]
  102. Moussa, M.; Ibrahim, M.; El Ghazaly, M.; Rohde, J.; Gnoth, S.; Anton, A.; Kensy, F.; Mueller, F. Expression of recombinant staphylokinase in the methylotrophic yeast Hansenula polymorpha. BMC Biotechnol. 2012, 12, 96. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  103. Filyak, Y.; Finiuk, N.; Mitina, N.; Bilyk, O.; Titorenko, V.; Hrydzhuk, O.; Zaichenko, A.; Stoika, R. A novel method for genetic transformation of yeast cells using oligoelectrolyte polymeric nanoscale carriers. Biotechniques 2013, 54, 35–43. [Google Scholar] [CrossRef] [PubMed]
  104. Kim, H.; Thak, E.J.; Lee, D.J.; Agaphonov, M.O.; Kang, H.A. Hansenula polymorpha Pmt4p Plays Critical Roles in O-Mannosylation of Surface Membrane Proteins and Participates in Heteromeric Complex Formation. PLoS ONE 2015, 10, e0129914. [Google Scholar] [CrossRef] [Green Version]
  105. Faber, K.N.; Haima, P.; Harder, W.; Veenhuis, M.; Ab, G. Highly-efficient electrotransformation of the yeast Hansenula polymorpha. Curr. Genet. 1994, 25, 305–310. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  106. Sohn, J.H.; Choi, E.S.; Kim, C.H.; Agaphonov, M.O.; Ter-Avanesyan, M.D.; Rhee, J.S.; Rhee, S.K. A novel autonomously replicating sequence (ARS) for multiple integration in the yeast Hansenula polymorpha DL-1. J. Bacteriol. 1996, 178, 4420–4428. [Google Scholar] [CrossRef] [Green Version]
  107. Saraya, R.; Krikken, A.M.; Kiel, J.A.; Baerends, R.J.; Veenhuis, M.; van der Klei, I.J. Novel genetic tools for Hansenula polymorpha. FEMS Yeast Res. 2012, 12, 271–278. [Google Scholar] [CrossRef]
  108. Faber, K.N.; Westra, S.; Waterham, H.R.; Keizer-Gunnink, I.; Harder, W.; Veenhuis, G.A. Foreign gene expression in Hansenula polymorpha. A system for the synthesis of small functional peptides. Appl. Microbiol. Biotechnol. 1996, 45, 72–79. [Google Scholar] [CrossRef] [Green Version]
  109. Kim, M.W.; Rhee, S.K.; Kim, J.Y.; Shimma, Y.; Chiba, Y.; Jigami, Y.; Kang, H.A. Characterization of N-linked oligosaccharides assembled on secretory recombinant glucose oxidase and cell wall mannoproteins from the methylotrophic yeast Hansenula polymorpha. Glycobiology 2004, 14, 243–251. [Google Scholar] [CrossRef] [Green Version]
  110. Wetzel, D.; Barbian, A.; Jenzelewski, V.; Schembecker, G.; Merz, J.; Piontek, M. Bioprocess optimization for purification of chimeric VLP displaying BVDV E2 antigens produced in yeast Hansenula polymorpha. J. Biotechnol. 2019, 306, 203–212. [Google Scholar] [CrossRef]
  111. McGregor, J.; Hardy, J.M.; Lay, C.S.; Boo, I.; Piontek, M.; Suckow, M.; Coulibaly, F.; Poumbourios, P.; Center, R.J.; Drummer, H.E. Virus-Like Particles Containing the E2 Core Domain of Hepatitis C Virus Generate Broadly Neutralizing Antibodies in Guinea Pigs. J. Virol. 2022, 96, e0167521. [Google Scholar] [CrossRef]
  112. Wetzel, D.; Chan, J.A.; Suckow, M.; Barbian, A.; Weniger, M.; Jenzelewski, V.; Reiling, L.; Richards, J.S.; Anderson, D.A.; Kouskousis, B.; et al. Display of malaria transmission-blocking antigens on chimeric duck hepatitis B virus-derived virus-like particles produced in Hansenula polymorpha. PLoS ONE 2019, 14, e0221394. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  113. Cheon, S.A.; Kim, H.; Oh, D.B.; Kwon, O.; Kang, H.A. Remodeling of the glycosylation pathway in the methylotrophic yeast Hansenula polymorpha to produce human hybrid-type N-glycans. J. Microbiol. 2012, 50, 341–348. [Google Scholar] [CrossRef] [PubMed]
  114. Xu, X.; Ren, S.; Chen, X.; Ge, J.; Xu, Z.; Huang, H.; Sun, H.; Gu, Y.; Zhou, T.; Li, J.; et al. Generation of hepatitis B virus PreS2-S antigen in Hansenula polymorpha. Virol. Sin. 2014, 29, 403–409. [Google Scholar] [CrossRef]
  115. Hardy, E.; Martinez, E.; Diago, D.; Diaz, R.; Gonzalez, D.; Herrera, L. Large-scale production of recombinant hepatitis B surface antigen from Pichia pastoris. J. Biotechnol. 2000, 77, 157–167. [Google Scholar] [CrossRef] [PubMed]
  116. Wetzel, D.; Rolf, T.; Suckow, M.; Kranz, A.; Barbian, A.; Chan, J.A.; Leitsch, J.; Weniger, M.; Jenzelewski, V.; Kouskousis, B.; et al. Establishment of a yeast-based VLP platform for antigen presentation. Microb. Cell Fact. 2018, 17, 17. [Google Scholar] [CrossRef]
  117. Shao, S.; Wang, Q.; Jin, Y.; Zhang, X.; Liu, Z.; Chen, S.; Wu, H.; Yang, S.; Tang, F.; Su, J.; et al. Recombinant Virus-like Particles of Human Parvovirus B19 with the Internal Location of VP1 Unique Region Produced by Hansenula polymorpha. Viruses 2022, 14, 2410. [Google Scholar] [CrossRef]
  118. Lorent, E.; Bierau, H.; Engelborghs, Y.; Verheyden, G.; Bosman, F. Structural characterisation of the hepatitis C envelope glycoprotein E1 ectodomain derived from a mammalian and a yeast expression system. Vaccine 2008, 26, 399–410. [Google Scholar] [CrossRef]
  119. Qian, W.; Aguilar, F.; Wang, T.; Qiu, B. Secretion of truncated recombinant rabies virus glycoprotein with preserved antigenic properties using a co-expression system in Hansenula polymorpha. J. Microbiol. 2013, 51, 234–240. [Google Scholar] [CrossRef]
  120. Klabunde, J.; Kleebank, S.; Piontek, M.; Hollenberg, C.P.; Hellwig, S.; Degelmann, A. Increase of calnexin gene dosage boosts the secretion of heterologous proteins by Hansenula polymorpha. FEMS Yeast Res. 2007, 7, 1168–1180. [Google Scholar] [CrossRef] [Green Version]
  121. Simanavicius, M.; Tamosiunas, P.L.; Petraityte-Burneikiene, R.; Johne, R.; Ulrich, R.G.; Zvirbliene, A.; Kucinskaite-Kodze, I. Generation in yeast and antigenic characterization of hepatitis E virus capsid protein virus-like particles. Appl. Microbiol. Biotechnol. 2018, 102, 185–198. [Google Scholar] [CrossRef]
  122. Su, C.X.; Gu, M.R.; Zhang, P.; Jin, Z.J.; Meng, F.H.; Chen, E.J.; Yang, Z.; Liu, Y.; Wang, Y.C. [Expression of ORF2 protein of HEV genotype IV in Hansenula polymorpha]. Sheng Wu Gong Cheng Xue Bao 2007, 23, 73–78. [Google Scholar]
  123. Burden, C.S.; Jin, J.; Podgornik, A.; Bracewell, D.G. A monolith purification process for virus-like particles from yeast homogenate. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 2012, 880, 82–89. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  124. Fu, J.; VanDusen, W.J.; Kolodin, D.G.; O’Keefe, D.O.; Herber, W.K.; George, H.A. Continuous culture study of the expression of hepatitis B surface antigen and its self-assembly into virus-like particles in Saccharomyces cerevisiae. Biotechnol. Bioeng. 1996, 49, 578–586. [Google Scholar] [CrossRef]
  125. Hadiji-Abbes, N.; Martin, M.; Benzina, W.; Karray-Hakim, H.; Gergely, C.; Gargouri, A.; Mokdad-Gargouri, R. Extraction and purification of hepatitis B virus-like M particles from a recombinant Saccharomyces cerevisiae strain using alumina powder. J. Virol. Methods 2013, 187, 132–137. [Google Scholar] [CrossRef]
  126. Hadiji-Abbes, N.; Mihoubi, W.; Martin, M.; Karakasyan-Dia, C.; Frikha, F.; Gergely, C.; Jouenne, T.; Gargouri, A.; Mokdad-Gargouri, R. Characterization of C69R variant HBsAg: Effect on binding to anti-HBs and the structure of virus-like particles. Arch. Virol. 2015, 160, 2427–2433. [Google Scholar] [CrossRef]
  127. Lunsdorf, H.; Gurramkonda, C.; Adnan, A.; Khanna, N.; Rinas, U. Virus-like particle production with yeast: Ultrastructural and immunocytochemical insights into Pichia pastoris producing high levels of the hepatitis B surface antigen. Microb. Cell Fact. 2011, 10, 48. [Google Scholar] [CrossRef] [Green Version]
  128. Hosseini, S.N.; Javidanbardan, A.; Alizadeh Salim, B.S.; Khatami, M. Large-scale purification of recombinant hepatitis B surface antigen from Pichia pastoris with non-affinity chromatographic methods as a substitute to immunoaffinity chromatography. Prep. Biochem. Biotechnol. 2018, 48, 683–692. [Google Scholar] [CrossRef] [PubMed]
  129. Gurramkonda, C.; Adnan, A.; Gabel, T.; Lunsdorf, H.; Ross, A.; Nemani, S.K.; Swaminathan, S.; Khanna, N.; Rinas, U. Simple high-cell density fed-batch technique for high-level recombinant protein production with Pichia pastoris: Application to intracellular production of Hepatitis B surface antigen. Microb. Cell Fact. 2009, 8, 13. [Google Scholar] [CrossRef] [Green Version]
  130. Stephen, S.L.; Beales, L.; Peyret, H.; Roe, A.; Stonehouse, N.J.; Rowlands, D.J. Recombinant Expression of Tandem-HBc Virus-Like Particles (VLPs). Methods Mol. Biol. 2018, 1776, 97–123. [Google Scholar] [CrossRef] [PubMed]
  131. Rolland, D.; Gauthier, M.; Dugua, J.M.; Fournier, C.; Delpech, L.; Watelet, B.; Letourneur, O.; Arnaud, M.; Jolivet, M. Purification of recombinant HBc antigen expressed in Escherichia coli and Pichia pastoris: Comparison of size-exclusion chromatography and ultracentrifugation. J. Chromatogr. B Biomed. Sci. Appl. 2001, 753, 51–65. [Google Scholar] [CrossRef]
  132. Pechelyulko, A.; Andreeva-Kovalevskaya, Z.; Dmitriev, D.; Lavrov, V.; Massino, Y.; Nagel, A.; Segal, O.; Sokolova, O.S.; Solonin, A.; Tarakanova, Y.; et al. A simple method to purify recombinant HCV core protein expressed in Pichia pastoris for obtaining virus-like particles and producing monoclonal antibodies. Protein Expr. Purif. 2021, 183, 105864. [Google Scholar] [CrossRef]
  133. Acosta-Rivero, N.; Aguilar, J.C.; Musacchio, A.; Falcon, V.; Vina, A.; de la Rosa, M.C.; Morales, J. Characterization of the HCV core virus-like particles produced in the methylotrophic yeast Pichia pastoris. Biochem. Biophys. Res. Commun. 2001, 287, 122–125. [Google Scholar] [CrossRef]
  134. Fazlalipour, M.; Keyvani, H.; Monavari, S.H.; Mollaie, H.R. Expression, Purification and Immunogenic Description of a Hepatitis C Virus Recombinant CoreE1E2 Protein Expressed by Yeast Pichia pastoris. Jundishapur J. Microbiol. 2015, 8, e17157. [Google Scholar] [CrossRef] [Green Version]
  135. Acosta-Rivero, N.; Rodriguez, A.; Musacchio, A.; Falcon, V.; Suarez, V.M.; Martinez, G.; Guerra, I.; Paz-Lago, D.; Morera, Y.; de la Rosa, M.C.; et al. In vitro assembly into virus-like particles is an intrinsic quality of Pichia pastoris derived HCV core protein. Biochem. Biophys. Res. Commun. 2004, 325, 68–74. [Google Scholar] [CrossRef]
  136. Acosta-Rivero, N.; Alvarez-Obregon, J.C.; Musacchio, A.; Falcon, V.; Duenas-Carrera, S.; Marante, J.; Menendez, I.; Morales, J. In vitro self-assembled HCV core virus-like particles induce a strong antibody immune response in sheep. Biochem. Biophys. Res. Commun. 2002, 290, 300–304. [Google Scholar] [CrossRef]
  137. Majeau, N.; Gagne, V.; Bolduc, M.; Leclerc, D. Signal peptide peptidase promotes the formation of hepatitis C virus non-enveloped particles and is captured on the viral membrane during assembly. J. Gen. Virol. 2005, 86, 3055–3064. [Google Scholar] [CrossRef]
  138. Freivalds, J.; Dislers, A.; Ose, V.; Pumpens, P.; Tars, K.; Kazaks, A. Highly efficient production of phosphorylated hepatitis B core particles in yeast Pichia pastoris. Protein Expr. Purif. 2011, 75, 218–224. [Google Scholar] [CrossRef] [PubMed]
  139. Kim, H.J.; Cho, S.Y.; Park, M.H. Comparison of the size distributions and immunogenicity of human papillomavirus type 16 L1 virus-like particles produced in insect and yeast cells. Arch. Pharm. Res. 2018, 41, 544–553. [Google Scholar] [CrossRef] [PubMed]
  140. Kim, H.J.; Jin, Y. The concentration of carbon source in the medium affects the quality of virus-like particles of human papillomavirus type 16 produced in Saccharomyces cerevisiae. PLoS ONE 2014, 9, e94467. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  141. Lowe, R.S.; Brown, D.R.; Bryan, J.T.; Cook, J.C.; George, H.A.; Hofmann, K.J.; Hurni, W.M.; Joyce, J.G.; Lehman, E.D.; Markus, H.Z.; et al. Human papillomavirus type 11 (HPV-11) neutralizing antibodies in the serum and genital mucosal secretions of African green monkeys immunized with HPV-11 virus-like particles expressed in yeast. J. Infect. Dis. 1997, 176, 1141–1145. [Google Scholar] [CrossRef] [PubMed]
  142. Cook, J.C.; Joyce, J.G.; George, H.A.; Schultz, L.D.; Hurni, W.M.; Jansen, K.U.; Hepler, R.W.; Ip, C.; Lowe, R.S.; Keller, P.M.; et al. Purification of virus-like particles of recombinant human papillomavirus type 11 major capsid protein L1 from Saccharomyces cerevisiae. Protein Expr. Purif. 1999, 17, 477–484. [Google Scholar] [CrossRef]
  143. Mach, H.; Volkin, D.B.; Troutman, R.D.; Wang, B.; Luo, Z.; Jansen, K.U.; Shi, L. Disassembly and reassembly of yeast-derived recombinant human papillomavirus virus-like particles (HPV VLPs). J. Pharm. Sci. 2006, 95, 2195–2206. [Google Scholar] [CrossRef]
  144. Kwag, H.L.; Kim, H.J.; Chang, D.Y. The production and immunogenicity of human papillomavirus type 58 virus-like particles produced in Saccharomyces cerevisiae. J. Microbiol. 2012, 50, 813–820. [Google Scholar] [CrossRef]
  145. Gupta, G.; Glueck, R.; Rishi, N. Physicochemical characterization and immunological properties of Pichia pastoris based HPV16L1 and 18L1 virus like particles. Biologicals 2017, 46, 11–22. [Google Scholar] [CrossRef]
  146. Jiang, Z.; Tong, G.; Cai, B.; Xu, Y.; Lou, J. Purification and immunogenicity study of human papillomavirus 58 virus-like particles expressed in Pichia pastoris. Protein Expr. Purif. 2011, 80, 203–210. [Google Scholar] [CrossRef] [PubMed]
  147. Hanumantha Rao, N.; Baji Babu, P.; Rajendra, L.; Sriraman, R.; Pang, Y.Y.; Schiller, J.T.; Srinivasan, V.A. Expression of codon optimized major capsid protein (L1) of human papillomavirus type 16 and 18 in Pichia pastoris; purification and characterization of the virus-like particles. Vaccine 2011, 29, 7326–7334. [Google Scholar] [CrossRef] [Green Version]
  148. Coimbra, E.C.; Gomes, F.B.; Campos, J.F.; D’Arc, M.; Carvalho, J.C.; Mariz, F.C.; Jesus, A.L.; Stocco, R.C.; Becak, W.; Freitas, A.C. Production of L1 protein from different types of HPV in Pichia pastoris using an integrative vector. Braz. J. Med. Biol. Res. 2011, 44, 1209–1214. [Google Scholar] [CrossRef] [Green Version]
  149. Dewi, K.S.; Chairunnisa, S.; Swasthikawati, S.; Yuliawati; Agustiyanti, D.F.; Mustopa, A.Z.; Kusharyoto, W.; Ningrum, R.A. Production of codon-optimized Human papillomavirus type 52 L1 virus-like particles in Pichia pastoris BG10 expression system. Prep. Biochem. Biotechnol. 2023, 53, 148–156. [Google Scholar] [CrossRef]
  150. Zhao, H.; Li, H.Y.; Han, J.F.; Deng, Y.Q.; Li, Y.X.; Zhu, S.Y.; He, Y.L.; Qin, E.D.; Chen, R.; Qin, C.F. Virus-like particles produced in Saccharomyces cerevisiae elicit protective immunity against Coxsackievirus A16 in mice. Appl. Microbiol. Biotechnol. 2013, 97, 10445–10452. [Google Scholar] [CrossRef] [PubMed]
  151. Zhang, C.; Liu, Q.; Ku, Z.; Hu, Y.; Ye, X.; Zhang, Y.; Huang, Z. Coxsackievirus A16-like particles produced in Pichia pastoris elicit high-titer neutralizing antibodies and confer protection against lethal viral challenge in mice. Antiviral. Res. 2016, 129, 47–51. [Google Scholar] [CrossRef] [PubMed]
  152. Zhou, Y.; Zhang, C.; Liu, Q.; Gong, S.; Geng, L.; Huang, Z. A virus-like particle vaccine protects mice against coxsackievirus A10 lethal infection. Antiviral. Res. 2018, 152, 124–130. [Google Scholar] [CrossRef]
  153. Wang, X.W.; Sheng, W.; Zeng, Y. [Formation and identification of virus-like particles of poliovirus type I]. Zhonghua Shi Yan He Lin Chuang Bing Du Xue Za Zhi 2013, 27, 373–375. [Google Scholar]
  154. Sherry, L.; Grehan, K.; Snowden, J.S.; Knight, M.L.; Adeyemi, O.O.; Rowlands, D.J.; Stonehouse, N.J. Comparative Molecular Biology Approaches for the Production of Poliovirus Virus-like Particles Using Pichia pastoris. mSphere 2020, 5, e00838-19. [Google Scholar] [CrossRef] [Green Version]
  155. Sherry, L.; Grehan, K.; Swanson, J.J.; Bahar, M.W.; Porta, C.; Fry, E.E.; Stuart, D.I.; Rowlands, D.J.; Stonehouse, N.J. Production and Characterisation of Stabilised PV-3 Virus-like Particles Using Pichia pastoris. Viruses 2022, 14, 2159. [Google Scholar] [CrossRef]
  156. Choi, Y.R.; Kim, H.J.; Lee, J.Y.; Kang, H.A. Chromatographically-purified capsid proteins of red-spotted grouper nervous necrosis virus expressed in Saccharomyces cerevisiae form virus-like particles. Protein Expr. Purif. 2013, 89, 162–168. [Google Scholar] [CrossRef]
  157. Barsoe, S.; Toffan, A.; Pascoli, F.; Stratmann, A.; Pretto, T.; Marsella, A.; Er-Rafik, M.; Vendramin, N.; Olesen, N.J.; Sepulveda, D.; et al. Long-Term Protection and Serologic Response of European Sea Bass Vaccinated with a Betanodavirus Virus-Like Particle Produced in Pichia pastoris. Vaccines 2021, 2, 447. [Google Scholar] [CrossRef]
  158. Lowin, T.; Raab, U.; Schroeder, J.; Franssila, R.; Modrow, S. Parvovirus B19 VP2-proteins produced in Saccharomyces cerevisiae: Comparison with VP2-particles produced by baculovirus-derived vectors. J. Vet. Med. B Infect. Dis. Vet. Public Health 2005, 52, 348–352. [Google Scholar] [CrossRef]
  159. Penkert, R.R.; Young, N.S.; Surman, S.L.; Sealy, R.E.; Rosch, J.; Dormitzer, P.R.; Settembre, E.C.; Chandramouli, S.; Wong, S.; Hankins, J.S.; et al. Saccharomyces cerevisiae-derived virus-like particle parvovirus B19 vaccine elicits binding and neutralizing antibodies in a mouse model for sickle cell disease. Vaccine 2017, 35, 3615–3620. [Google Scholar] [CrossRef] [PubMed]
  160. Chandramouli, S.; Medina-Selby, A.; Coit, D.; Schaefer, M.; Spencer, T.; Brito, L.A.; Zhang, P.; Otten, G.; Mandl, C.W.; Mason, P.W.; et al. Generation of a parvovirus B19 vaccine candidate. Vaccine 2013, 31, 3872–3878. [Google Scholar] [CrossRef] [PubMed]
  161. Freivalds, J.; Dislers, A.; Ose, V.; Skrastina, D.; Cielens, I.; Pumpens, P.; Sasnauskas, K.; Kazaks, A. Assembly of bacteriophage Qbeta virus-like particles in yeast Saccharomyces cerevisiae and Pichia pastoris. J. Biotechnol. 2006, 123, 297–303. [Google Scholar] [CrossRef] [PubMed]
  162. Bredell, H.; Smith, J.J.; Prins, W.A.; Gorgens, J.F.; van Zyl, W.H. Expression of rotavirus VP6 protein: A comparison amongst Escherichia coli, Pichia pastoris and Hansenula polymorpha. FEMS Yeast Res. 2016, 16, fow001. [Google Scholar] [CrossRef] [Green Version]
  163. Firdaus, M.E.R.; Mustopa, A.Z.; Ekawati, N.; Chairunnisa, S.; Arifah, R.K.; Hertati, A.; Irawan, S.; Prastyowati, A.; Kusumawati, A.; Nurfatwa, M. Optimization, characterization, comparison of self-assembly VLP of capsid protein L1 in yeast and reverse vaccinology design against human papillomavirus type 52. J. Genet. Eng. Biotechnol. 2023, 21, 68. [Google Scholar] [CrossRef]
  164. Weber, J.; Cheinsong-Popov, R.; Callow, D.; Adams, S.; Patou, G.; Hodgkin, K.; Martin, S.; Gotch, F.; Kingsman, A. Immunogenicity of the yeast recombinant p17/p24:Ty virus-like particles (p24-VLP) in healthy volunteers. Vaccine 1995, 13, 831–834. [Google Scholar] [CrossRef]
  165. Martins, S.A.; Santos, J.; Silva, R.D.M.; Rosa, C.; Cabo Verde, S.; Correia, J.D.G.; Melo, R. How promising are HIV-1-based virus-like particles for medical applications. Front. Cell Infect. Microbiol. 2022, 12, 997875. [Google Scholar] [CrossRef] [PubMed]
Figure 1. An overview of platforms for the production of VLPs and their applications. They are used in the manufacturing of vaccines, as carriers of drugs or nucleic acids; as nanocarriers for antigen presentation; conjugated with contrast agents for clinical imaging (for computed tomography, magnetic resonance imaging, and positron emission tomography), with photothermal agents for theragnostic applications, and with fluorescent dyes for optical imaging. Created with BioRender.com.
Figure 1. An overview of platforms for the production of VLPs and their applications. They are used in the manufacturing of vaccines, as carriers of drugs or nucleic acids; as nanocarriers for antigen presentation; conjugated with contrast agents for clinical imaging (for computed tomography, magnetic resonance imaging, and positron emission tomography), with photothermal agents for theragnostic applications, and with fluorescent dyes for optical imaging. Created with BioRender.com.
Applmicrobiol 03 00056 g001
Figure 2. Schematic representation of non-enveloped and enveloped viruses. Created with BioRender.com.
Figure 2. Schematic representation of non-enveloped and enveloped viruses. Created with BioRender.com.
Applmicrobiol 03 00056 g002
Figure 3. Representative N-glycan subtypes in S. cerevisiae, methylotrophic yeasts, and humans. Created with BioRender.com.
Figure 3. Representative N-glycan subtypes in S. cerevisiae, methylotrophic yeasts, and humans. Created with BioRender.com.
Applmicrobiol 03 00056 g003
Figure 4. Comparison of yeast manipulation tools, features, and parameters to be considered for the selection of the yeast species for VLP production. Yeast cells of S. cerevisiae, P. pastoris, and H. polymorpha are represented with the organelles to highlight the structural differences. The Golgi apparatus of S. cerevisiae is organized in cisternae scattered throughout the cytoplasm; while in methylotrophic yeasts, the Golgi apparatus is organized in stacked cisternae dispersed in the cytoplasm resembling those of mammalian cells. Methylotrophic yeasts are represented with a higher number of peroxisomes than S. cerevisiae to highlight their increase during growth in the presence of methanol. Genetic tools, such as mutant strains, plasmids, and glycosylation humanized strains have been developed for the three species. Carbon sources indicated in the figure are those preferentially used for heterologous protein expression; thermotolerance refers to the ability to grow at a temperature over 30 °C. Hyper-mannosylation of proteins observed in S. cerevisiae means that the mannose chain is composed of more than 100 residues. Secretion in the culture medium, although occurring in the three species, has been harnessed mainly in P. pastoris. Created with BioRender.com.
Figure 4. Comparison of yeast manipulation tools, features, and parameters to be considered for the selection of the yeast species for VLP production. Yeast cells of S. cerevisiae, P. pastoris, and H. polymorpha are represented with the organelles to highlight the structural differences. The Golgi apparatus of S. cerevisiae is organized in cisternae scattered throughout the cytoplasm; while in methylotrophic yeasts, the Golgi apparatus is organized in stacked cisternae dispersed in the cytoplasm resembling those of mammalian cells. Methylotrophic yeasts are represented with a higher number of peroxisomes than S. cerevisiae to highlight their increase during growth in the presence of methanol. Genetic tools, such as mutant strains, plasmids, and glycosylation humanized strains have been developed for the three species. Carbon sources indicated in the figure are those preferentially used for heterologous protein expression; thermotolerance refers to the ability to grow at a temperature over 30 °C. Hyper-mannosylation of proteins observed in S. cerevisiae means that the mannose chain is composed of more than 100 residues. Secretion in the culture medium, although occurring in the three species, has been harnessed mainly in P. pastoris. Created with BioRender.com.
Applmicrobiol 03 00056 g004
Table 1. Comparison of features of the different VLP production platforms.
Table 1. Comparison of features of the different VLP production platforms.
BacteriaYeastMammalian CellsInsect CellsPlant
Production costLowLowHighHighModerate
Type of growth mediaSimpleSimpleComplexComplexSimple
Growth speedVery highHighModerateModerateVery slow
Production timeLowLowHighHighVery high
Expression yieldHighHighLowVery highLow
SecretionNoYesYesYesNot applicable
Enveloped/
non-enveloped VLPs
Non-envelopedNon-enveloped
(enveloped only in some cases)
Enveloped/
Non-enveloped
Enveloped/
non-enveloped
Not applicable
ScalabilityEasyEasyVery difficultVery difficultDifficult
SafetySafe
(possibility of endotoxins)
Very safeSafe
(possible contamination with human viruses)
Very safeVery safe
Genetic manipulationVery easyEasyDifficultDifficultDifficult
Glycosylation of
proteins
Very different from humansDifferent from humans (can be optimized)Reproducing human glycosylationSimpler N-glycosylation pattern compared to mammalian cellsHuman-like
glycosylation
PTMsLack of PTM systemLack of complex PTM pathwayComplex PTM pathwayComplex PTM pathwayComplex PTM pathway
Table 2. List of virus proteins that have been expressed in yeast species to produce VLPs, grouped according to virus family.
Table 2. List of virus proteins that have been expressed in yeast species to produce VLPs, grouped according to virus family.
FamilyVirus Species
HepadnaviridaeHepatitis B Virus, Hepatitis E Virus,
FlaviviridaeHepatitis C Virus, Japanese Encephalitis Virus, Bovine Viral diarrhea virus, Tick-borne encephalitis virus, Zika virus
PapillomaviridaeHuman Papilloma Virus 1, 6, 11, 16, 52, 58, Cottontail rabbit Papillomavirus, bovine papilloma virus 1,2, 4
Picornaviridae Enterovirus D68, Enterovirus 71 and Coxsackievirus A6, A10 and A16, Poliovirus type I
NodaviridaeRedspotted grouper nervous necrosis virus, Nervous necrosis virus
ParvoviridaePorcine parvovirus, Adeno associated virus, Human Parvovirus 4, B19, Human bocaviruses
ParamyxoviridaeSendai virus, Tioman virus, Human parainfluenza virus 2 and 4, Menangle virus, Nipah virus
CircoviridaePorcine circovirus
RetroviridaeHIV
KolmioviridaeHepatitis Delta Virus
FiersviridaeCacteriophage Qbeta virus
SedoreoviridaeRotavirus
PotyviridaeJohnsongrass mosaic virus
PolyomaviridaeHuman polyoma virus, hamster polyoma virus, bird polyomavirus, Goose hemorrhagic, Polyomavirus
CaliciviridaeNorovirus, Rabbit hemorrhagic disease virus
BromoviridaeCowpea chlorotic mottle virus
BirnaviridaeInfectious bursal disease virus
SecoviridaeGrapevine fanleaf virus
TogaviridaeChikungunya virus
IridoviridaeChinese Giant Salamander iridovirus
Most information about the expression systems are taken from [30]. Virus classification was retrieved from https://ictv.global/taxonomy (accessed on 4 July 2023).
Table 3. Main inducible and constitutive promoters used to produce VLPs in the yeast species.
Table 3. Main inducible and constitutive promoters used to produce VLPs in the yeast species.
Expression Promoters
Type of VectorsSaccharomyces cerevisiaePichia pastorisHansenula polymorpha
Replicative, InducibleGAL1, GAL10, GAL7, GAL1/10, hybrid GAL10-PYK11,
hybrid GAL10-CYC1
Replicative, ConstitutiveGAD, ADH/GAPDH, PGK1, TEF1, ADC1
Integrative, Inducible AOX1MOX, FMD
Integrative, Constitutive GAP, PGK1
Replicative vectors may carry ARS or a 2 µ origin of replication. Integrative vectors are usually cut out with specific restriction endonulases and inserted into the genomic DNA of P. pastoris or H. polymorpha. Most information about the expression systems are taken from [30] and references within. Promoters derived from GAL1, GAL10, and GAL1/10 are inducible by galactose. The hybrid promoters are constructed by the galactose responsive DNA binding-domain and the transcription activation site of cytochrome C1 (CYC1) or pyruvate kinase gene (PYK11). GAL1: Galactokinase, GAL10: UDP-glucose-4-epimerase, GAL7: Galactose-1-phosphate uridyl transferase, PGK1: 3-phosphoglycerate kinase, ADH: Alcohol dehydrogenase, GAPDH: Glyceraldehyde-3-phosphate dehydrogenase, TEF1: Translational elongation factor EF-1 alpha, ADC: Arginine decarboxylase, AOX1: Alcohol oxidase, 1: GAP: Glyceraldehyde-3-phosphate dehydrogenase, MOX: Methanol oxidase, FMD: Formato dehydrogenase.
Table 4. Summary of VLPS produced in more than one yeast species.
Table 4. Summary of VLPS produced in more than one yeast species.
Type of Antigens
VirusS. cerevisiaeP. pastorisH. polymorpha
Hepatitis E virus-HEV-3: full length capsid protein (ORF2, aa 1–660); 5′ and 3′ terminally truncated capsid protein (ORF2, aa 112–608)
-Rat HEV: full length capsid protein (ORF2, aa 1–645); 5′ and 3′ terminally truncated capsid protein (ORF2, aa 112–608) [121]
ORF2, aa 112–608 [90]ORF2, aa 112–607 (HEV genotype IV) [122]
Hepatitis B virus-Surface protein (HBsAg) [123,124]
-Viral M [preS2 + S] [125]
-Wild-type and mutant C69R S genes [126]
-Surface protein (HBsAg) [115,127,128,129]
-Core protein (HBc) [130,131]
-26 amino acids of PreS2 C-terminus (aa 120–145) [114]
Hepatitis C virus -Core protein (HBc) [132,133]
-CoreE1E2 protein, which consists of Core (269 nt–841nt) E1 (842 nt–1417nt), and E2 (1418 nt–2506nt) [134,135,136,137,138]
E2 Core Domain [111]
HPV 16, 11, 6, 58Human papillomavirus major capsid protein L1 [139,140,141,142,143,144]-Human papillomavirus major capsid protein L1 [85,86,145,146,147,148,149]
CoxsackievirusCapsid protein precursor P1 and the protease 3CD of Coxsackievirus A16 [150]-Capsid protein precursor P1 and the protease 3CD Coxsackievirus A16 [74,151]
-Capsid protein precursor P1 and the protease 3CD of Coxsackievirus A10 [152]
PoliovirusCapsid precursor protein P1 and the protease 3CD [153]Capsid precursor protein P1 and the protease 3CD [154,155]
Red-spotted grouper nervous necrosis virusCapsid protein [156]Capsid protein [157]
B19 parvovirusMinor-capsid protein VP1 and the major-capsid protein VP2 [158,159,160] Minor-capsid protein VP1 and the major-capsid protein VP2 [117]
Bacteriophage QβCoat protein (CP) [161]Coat protein (CP) [161]
Phage PP7
φCb5;
Phages fr
Phage SP
Coat proteins [161]Coat proteins [161]
Rotavirus Capsid protein VP6 [162]Capsid protein VP6 [162]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Brachelente, S.; Galli, A.; Cervelli, T. Yeast and Virus-like Particles: A Perfect or Imperfect Couple? Appl. Microbiol. 2023, 3, 805-825. https://0-doi-org.brum.beds.ac.uk/10.3390/applmicrobiol3030056

AMA Style

Brachelente S, Galli A, Cervelli T. Yeast and Virus-like Particles: A Perfect or Imperfect Couple? Applied Microbiology. 2023; 3(3):805-825. https://0-doi-org.brum.beds.ac.uk/10.3390/applmicrobiol3030056

Chicago/Turabian Style

Brachelente, Sara, Alvaro Galli, and Tiziana Cervelli. 2023. "Yeast and Virus-like Particles: A Perfect or Imperfect Couple?" Applied Microbiology 3, no. 3: 805-825. https://0-doi-org.brum.beds.ac.uk/10.3390/applmicrobiol3030056

Article Metrics

Back to TopTop