scholarly journals Production of Recombinant EAV with Tagged Structural Protein Gp3 to Study Artervirus Minor Protein Localization in Infected Cells

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 735
Author(s):  
Anna Karolina Matczuk ◽  
Grzegorz Chodaczek ◽  
Maciej Ugorski
Keyword(s):  
Protein Localization ◽  
Open Reading Frames ◽  
Equine Arteritis Virus ◽  
Structural Protein ◽  
N Protein ◽  
Virus Attachment ◽  
Recombinant Viruses ◽  
E Protein ◽  
Host Cell Factors ◽  
Minor Protein

Equine arteritis virus (EAV) is a prototype member of the Arterivirus family, comprising important pathogens of domestic animals. Minor glycoproteins of Arteriviruses are responsible for virus entry and cellular tropism. The experimental methods for studying minor Arterivirus proteins are limited because of the lack of antibodies and nested open reading frames (ORFs). In this study, we generated recombinant EAV with separated ORFs 3 and 4, and Gp3 carrying HA-tag (Gp3-HA). The recombinant viruses were stable on passaging and replicated in titers similar to the wild-type EAV. Gp3-HA was incorporated into the virion particles as monomers and as a Gp2/Gp3-HA/Gp4 trimer. Gp3-HA localized in ER and, to a lesser extent, in the Golgi, it also co-localized with the E protein but not with the N protein. The co-localization of Gp3-HA and the E protein with ERGIC was reduced. Moreover, EAV with Gp3-HA could become a valuable research tool for identifying host cell factors during infection and the role of Gp3 in virus attachment and entry.

scholarly journals Nuclear localization of non-structural protein 1 and nucleocapsid protein of equine arteritis virus

2002 ◽  
Vol 83 (4) ◽  
pp. 795-800 ◽  
Author(s):  
Marieke A. Tijms ◽  
Yvonne van der Meer ◽  
Eric J. Snijder
Keyword(s):  
Nuclear Localization ◽  
Nuclear Export ◽  
Virus Assembly ◽  
Equine Arteritis Virus ◽  
Genome Replication ◽  
Structural Protein ◽  
Leptomycin B ◽  
Nuclear Retention ◽  
N Protein ◽  
Cytoplasmic Membranes

RNA synthesis (genome replication and subgenomic mRNA transcription) directed by equine arteritis virus (EAV; family Arteriviridae, order Nidovirales) occurs on modified cytoplasmic membranes to which most viral replicase subunits localize. Remarkably, a fraction of non-structural protein 1 (nsp1), a protein essential for transcription but dispensable for genome replication, is present in the host cell nucleus, in particular during the earlier stages of infection. Expression of GFP-tagged fusion proteins revealed that nsp1 is actively imported into the nucleus. Although the signals responsible for nsp1 transport could not be identified, our studies revealed that another EAV protein with a partially nuclear localization, the nucleocapsid (N) protein, utilizes the CRM1-mediated nuclear export pathway. Inactivation of this pathway with the drug leptomycin B resulted in the unexpected and immediate nuclear retention of all N protein molecules, thus revealing that the protein shuttles between cytoplasm and nucleus before playing its role in cytoplasmic virus assembly.

scholarly journals An inactivated recombinant rabies virus displaying the Zika virus prM-E induces protective immunity against both pathogens

2021 ◽  
Vol 15 (6) ◽  
pp. e0009484
Author(s):  
Hongli Jin ◽  
Cuicui Jiao ◽  
Zengguo Cao ◽  
Pei Huang ◽  
Hang Chi ◽  
...  
Keyword(s):  
T Cells ◽  
Rabies Virus ◽  
Signal Peptide ◽  
Zika Virus ◽  
Transmembrane Domain ◽  
Protein Localization ◽  
Foreign Protein ◽  
Effective Vaccine ◽  
Recombinant Viruses ◽  
E Protein

The global spread of Zika virus (ZIKV), which caused a pandemic associated with Congenital Zika Syndrome and neuropathology in newborns and adults, prompted the pursuit of a safe and effective vaccine. Here, three kinds of recombinant rabies virus (RABV) encoding the prM-E protein of ZIKV were constructed: ZI-D (prM-E), ZI-E (transmembrane domain (TM) of prM-E replaced with RABV G) and ZI-F (signal peptide and TM domain of prM-E replaced with the region of RABV G). When the TM of prM-E was replaced with the region of RABV G (termed ZI-E), it promoted ZIKV E protein localization on the cell membrane and assembly on recombinant viruses. In addition, the change in the signal peptide with RABV G (termed ZI-F) was not conducive to foreign protein expression. The immunogenicity of recombinant viruses mixed with a complex adjuvant of ISA 201 VG and poly(I:C) was tested in BALB/c mice. After immunization with ZI-E, the anti-ZIKV IgG antibody lasted for at least 10 weeks. The titers of neutralizing antibodies (NAbs) against ZIKV and RABV at week 6 were all greater than the protective titers. Moreover, ZI-E stimulated the proliferation of splenic lymphocytes and promoted the secretion of cytokines. It also promoted the production of central memory T cells (TCMs) among CD4+/CD8+ T cells and stimulated B cell activation and maturation. These results indicate that ZI-E could induce ZIKV-specific humoral and cellular immune responses, which have the potential to be developed into a promising vaccine for protection against both ZIKV and RABV infections.

scholarly journals Neither the RNA nor the Proteins of Open Reading Frames 3a and 3b of the Coronavirus Infectious Bronchitis Virus Are Essential for Replication

2006 ◽  
Vol 80 (1) ◽  
pp. 296-305 ◽  
Author(s):  
Teri Hodgson ◽  
Paul Britton ◽  
Dave Cavanagh
Keyword(s):  
Infectious Bronchitis Virus ◽  
Open Reading Frames ◽  
Wild Type Virus ◽  
Type Virus ◽  
Structural Protein ◽  
Wild Type ◽  
Infectious Bronchitis ◽  
E Protein ◽  
Initiation Of Translation ◽  
Reading Frames

ABSTRACT Gene 3 of infectious bronchitis virus is tricistronic; open reading frames (ORFs) 3a and 3b encode two small nonstructural (ns) proteins, 3a and 3b, of unknown function, and a third, structural protein E, is encoded by ORF 3c. To determine if either the 3a or the 3b protein is required for replication, we first modified their translation initiation codons to prevent translation of the 3a and 3b proteins from recombinant infectious bronchitis viruses (rIBVs). Replication in primary chick kidney (CK) cells and in chicken embryos was not affected. In chicken tracheal organ cultures (TOCs), the recombinant rIBVs reached titers similar to those of the wild-type virus, but in the case of viruses lacking the 3a protein, the titer declined reproducibly earlier. Translation of the IBV E protein is believed to be initiated by internal entry of ribosomes at a structure formed by the sequences corresponding to ORFs 3a and 3b. To assess the necessity of this mechanism, we deleted most of the sequence representing 3a and 3b to produce a gene in which ORF 3c (E) was adjacent to the gene 3 transcription-associated sequence. Western blot analysis revealed that the recombinant IBV produced fivefold less E protein. Nevertheless, titers produced in CK cells, embryos, and TOCs were similar to those of the wild-type virus, although they declined earlier in TOCs, probably due to the absence of the 3a protein. Thus, neither the tricistronic arrangement of gene 3, the internal initiation of translation of E protein, nor the 3a and 3b proteins are essential for replication per se, suggesting that these proteins are accessory proteins that may have roles in vivo.

scholarly journals Identification of a Novel Structural Protein of Arteriviruses

1999 ◽  
Vol 73 (8) ◽  
pp. 6335-6345 ◽  
Author(s):  
Eric J. Snijder ◽  
Hans van Tol ◽  
Ketil W. Pedersen ◽  
Martin J. B. Raamsman ◽  
Antoine A. F. de Vries
Keyword(s):  
Reverse Genetics ◽  
Equine Arteritis Virus ◽  
Progeny Virus ◽  
Replicase Gene ◽  
Structural Protein ◽  
Reading Frame ◽  
Novel Gene ◽  
E Protein ◽  
C Terminus ◽  
Infected Cells

ABSTRACT Arteriviruses are positive-stranded RNA viruses with an efficiently organized, polycistronic genome. A short region between the replicase gene and open reading frame (ORF) 2 of the equine arteritis virus (EAV) genome was previously assumed to be untranslated. However, here we report that this segment of the EAV genome contains the 5′ part of a novel gene (ORF 2a) which is conserved in all arteriviruses. The 3′ part of EAV ORF 2a overlaps with the 5′ part of the former ORF 2 (now renamed ORF 2b), which encodes the GS glycoprotein. Both ORF 2a and ORF 2b appear to be expressed from mRNA 2, which thereby constitutes the first proven example of a bicistronic mRNA in arteriviruses. The 67-amino-acid protein encoded by EAV ORF 2a, which we have provisionally named the envelope (E) protein, is very hydrophobic and has a basic C terminus. An E protein-specific antiserum was raised and used to demonstrate the expression of the novel gene in EAV-infected cells. The EAV E protein proved to be very stable, did not form disulfide-linked oligomers, and was not N-glycosylated. Immunofluorescence and immunoelectron microscopy studies showed that the E protein associates with intracellular membranes both in EAV-infected cells and upon independent expression. An analysis of purified EAV particles revealed that the E protein is a structural protein. By using reverse genetics, we demonstrated that both the EAV E and GS proteins are essential for the production of infectious progeny virus.

scholarly journals Site-specific N-glycosylation analysis of animal cell culture-derived Zika virus proteins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Pralow ◽  
Alexander Nikolay ◽  
Arnaud Leon ◽  
Yvonne Genzel ◽  
Erdmann Rapp ◽  
...  
Keyword(s):  
Zika Virus ◽  
Animal Cell ◽  
Gradient Centrifugation ◽  
Viral Envelope ◽  
Protein Glycosylation ◽  
High Yield ◽  
Structural Protein ◽  
Site Specific ◽  
E Protein ◽  
The Impact

AbstractHere, we present for the first time, a site-specific N-glycosylation analysis of proteins from a Brazilian Zika virus (ZIKV) strain. The virus was propagated with high yield in an embryo-derived stem cell line (EB66, Valneva SE), and concentrated by g-force step-gradient centrifugation. Subsequently, the sample was proteolytically digested with different enzymes, measured via a LC–MS/MS-based workflow, and analyzed in a semi-automated way using the in-house developed glyXtoolMS software. The viral non-structural protein 1 (NS1) was glycosylated exclusively with high-mannose structures on both potential N-glycosylation sites. In case of the viral envelope (E) protein, no specific N-glycans could be identified with this method. Nevertheless, N-glycosylation could be proved by enzymatic de-N-glycosylation with PNGase F, resulting in a strong MS-signal of the former glycopeptide with deamidated asparagine at the potential N-glycosylation site N444. This confirmed that this site of the ZIKV E protein is highly N-glycosylated but with very high micro-heterogeneity. Our study clearly demonstrates the progress made towards site-specific N-glycosylation analysis of viral proteins, i.e. for Brazilian ZIKV. It allows to better characterize viral isolates, and to monitor glycosylation of major antigens. The method established can be applied for detailed studies regarding the impact of protein glycosylation on antigenicity and human pathogenicity of many viruses including influenza virus, HIV and corona virus.

scholarly journals Open reading frame 2 of porcine circovirus type 2 encodes a major capsid protein

2000 ◽  
Vol 81 (9) ◽  
pp. 2281-2287 ◽  
Author(s):  
Porntippa Nawagitgul ◽  
Igor Morozov ◽  
Steven R. Bolin ◽  
Perry A. Harms ◽  
Steven D. Sorden ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Gene Product ◽  
Protein S ◽  
Basic Amino Acid ◽  
Porcine Circovirus Type ◽  
Open Reading Frames ◽  
Porcine Circovirus ◽  
Structural Protein ◽  
Major Structural Protein ◽  
Orf2 Protein

Porcine circovirus 2 (PCV2), a single-stranded DNA virus associated with post-weaning multisystemic wasting syndrome of swine, has two potential open reading frames, ORF1 and ORF2, greater than 600 nucleotides in length. ORF1 is predicted to encode a replication-associated protein (Rep) essential for replication of viral DNA, while ORF2 contains a conserved basic amino acid sequence at the N terminus resembling that of the major structural protein of chicken anaemia virus. Thus far, the structural protein(s) of PCV2 have not been identified. In this study, a viral structural protein of 30 kDa was identified in purified PCV2 particles. ORF2 of PCV2 was cloned into a baculovirus expression vector and the gene product was expressed in insect cells. The expressed ORF2 gene product had a molecular mass of 30 kDa, similar to that detected in purified virus particles. The recombinant ORF2 protein self-assembled to form capsid-like particles when viewed by electron microscopy. Antibodies against the ORF2 protein were detected in samples of sera obtained from pigs as early as 3 weeks after experimental infection with PCV2. These results show that the major structural protein of PCV2 is encoded by ORF2 and has a molecular mass of 30 kDa.

scholarly journals Diterpenes/Diterpenoids and Their Derivatives as Potential Bioactive Leads against Dengue Virus: A Computational and Network Pharmacology Study

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6821
Author(s):  
Rasel Ahmed Khan ◽  
Rajib Hossain ◽  
Abolghasem Siyadatpanah ◽  
Khattab Al-Khafaji ◽  
Abul Bashar Ripon Khalipha ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Dengue Fever ◽  
Computational Study ◽  
Viral Proteins ◽  
Network Pharmacology ◽  
Binding Affinities ◽  
Ns1 Protein ◽  
Structural Protein ◽  
E Protein

Dengue fever is a dangerous infectious endemic disease that affects over 100 nations worldwide, from Africa to the Western Pacific, and is caused by the dengue virus, which is transmitted to humans by an insect bite of Aedes aegypti. Millions of citizens have died as a result of dengue fever and dengue hemorrhagic fever across the globe. Envelope (E), serine protease (NS3), RNA-directed RNA polymerase (NS5), and non-structural protein 1 (NS1) are mostly required for cell proliferation and survival. Some of the diterpenoids and their derivatives produced by nature possess anti-dengue viral properties. The goal of the computational study was to scrutinize the effectiveness of diterpenoids and their derivatives against dengue viral proteins through in silico study. Methods: molecular docking was performed to analyze the binding affinity of compounds against four viral proteins: the envelope (E) protein, the NS1 protein, the NS3 protein, and the NS5 protein. Results: among the selected drug candidates, triptolide, stevioside, alepterolic acid, sphaeropsidin A, methyl dodovisate A, andrographolide, caesalacetal, and pyrimethamine have demonstrated moderate to good binding affinities (−8.0 to −9.4 kcal/mol) toward the selected proteins: E protein, NS3, NS5, and NS1 whereas pyrimethamine exerts −7.5, −6.3, −7.8, and −6.6 kcal/mol with viral proteins, respectively. Interestingly, the binding affinities of these lead compounds were better than those of an FDA-approved anti-viral medication (pyrimethamine), which is underused in dengue fever. Conclusion: we can conclude that diterpenoids can be considered as a possible anti-dengue medication option. However, in vivo investigation is recommended to back up the conclusions of this study.

scholarly journals Genome Sequence and Global Gene Expression of Q54, a New Phage Species Linking the 936 and c2 Phage Species of Lactococcus lactis

2006 ◽  
Vol 188 (17) ◽  
pp. 6101-6114 ◽  
Author(s):  
Louis-Charles Fortier ◽  
Ali Bransi ◽  
Sylvain Moineau
Keyword(s):  
Gene Expression ◽  
Lactococcus Lactis ◽  
Genomic Sequence ◽  
Global Gene Expression ◽  
Open Reading Frames ◽  
Early Gene ◽  
Structural Protein ◽  
Translational Frameshifting ◽  
First Case ◽  
Tail Protein

ABSTRACT The lytic lactococcal phage Q54 was previously isolated from a failed sour cream production. Its complete genomic sequence (26,537 bp) is reported here, and the analysis indicated that it represents a new Lactococcus lactis phage species. A striking feature of phage Q54 is the low level of similarity of its proteome (47 open reading frames) with proteins in databases. A global gene expression study confirmed the presence of two early gene modules in Q54. The unusual configuration of these modules, combined with results of comparative analysis with other lactococcal phage genomes, suggests that one of these modules was acquired through recombination events between c2- and 936-like phages. Proteolytic cleavage and cross-linking of the major capsid protein were demonstrated through structural protein analyses. A programmed translational frameshift between the major tail protein (MTP) and the receptor-binding protein (RBP) was also discovered. A “shifty stop” signal followed by putative secondary structures is likely involved in frameshifting. To our knowledge, this is only the second report of translational frameshifting (+1) in double-stranded DNA bacteriophages and the first case of translational coupling between an MTP and an RBP. Thus, phage Q54 represents a fascinating member of a new species with unusual characteristics that brings new insights into lactococcal phage evolution.

scholarly journals The Unstructured Paramyxovirus Nucleocapsid Protein Tail Domain Modulates Viral Pathogenesis through Regulation of Transcriptase Activity

2018 ◽  
Vol 92 (8) ◽  
pp. e02064-17 ◽  
Author(s):  
Vidhi D. Thakkar ◽  
Robert M. Cox ◽  
Bevan Sawatsky ◽  
Renata da Fontoura Budaszewski ◽  
Julien Sourimant ◽  
...  
Keyword(s):  
Viral Pathogenesis ◽  
Tail Domain ◽  
Lethal Challenge ◽  
N Protein ◽  
Recombinant Viruses ◽  
Transcriptase Activity ◽  
Efficient Replication ◽  
Viral Attenuation ◽  
N Proteins

ABSTRACTThe paramyxovirus replication machinery comprises the viral large (L) protein and phosphoprotein (P-protein) in addition to the nucleocapsid (N) protein, which encapsidates the single-stranded RNA genome. Common to paramyxovirus N proteins is a C-terminal tail (Ntail). The mechanistic role and relevance for virus replication of the structurally disordered central Ntail section are unknown. Focusing initially on members of theMorbillivirusgenus, a series of measles virus (MeV) and canine distemper virus (CDV) N proteins were generated with internal deletions in the unstructured tail section. N proteins with large tail truncations remained bioactive in mono- and polycistronic minireplicon assays and supported efficient replication of recombinant viruses. Bioactivity of Ntail mutants extended to N proteins derived from highly pathogenic Nipah virus. To probe an effect of Ntail truncations on viral pathogenesis, recombinant CDVs were analyzed in a lethal CDV/ferret model of morbillivirus disease. The recombinant viruses displayed different stages of attenuation ranging from ameliorated clinical symptoms to complete survival of infected animals, depending on the molecular nature of the Ntail truncation. Reinfection of surviving animals with pathogenic CDV revealed robust protection against a lethal challenge. The highly attenuated virus was genetically stable afterex vivopassaging and recovery from infected animals. Mechanistically, gradual viral attenuation coincided with stepwise altered viral transcriptase activity in infected cells. These results identify the central Ntail section as a determinant for viral pathogenesis and establish a novel platform to engineer gradual virus attenuation for next-generation paramyxovirus vaccine design.IMPORTANCEInvestigating the role of the paramyxovirus N protein tail domain (Ntail) in virus replication, we demonstrated in this study that the structurally disordered central Ntail region is a determinant for viral pathogenesis. We show that internal deletions in this Ntail region of up to 55 amino acids in length are compatible with efficient replication of recombinant viruses in cell culture but result in gradual viral attenuation in a lethal canine distemper virus (CDV)/ferret model. Mechanistically, we demonstrate a role of the intact Ntail region in the regulation of viral transcriptase activity. Recombinant viruses with Ntail truncations induce protective immunity against lethal challenge of ferrets with pathogenic CDV. This identification of the unstructured central Ntail domain as a nonessential paramyxovirus pathogenesis factor establishes a foundation for harnessing Ntail truncations for vaccine engineering against emerging and reemerging members of the paramyxovirus family.

scholarly journals Emerging Novel GII.P16 Noroviruses Associated with Multiple Capsid Genotypes

Viruses ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 535 ◽  
Author(s):  
Leslie Barclay ◽  
Jennifer L. Cannon ◽  
Mary E. Wikswo ◽  
Annie R. Phillips ◽  
Hannah Browne ◽  
...  
Keyword(s):  
Amino Acid ◽  
Severe Case ◽  
Molecular Data ◽  
Antigenic Drift ◽  
The Novel ◽  
Structural Protein ◽  
Protein Coding ◽  
Recombinant Viruses ◽  
The Us ◽  
Genomic Regions

Noroviruses evolve by antigenic drift and recombination, which occurs most frequently at the junction between the non-structural and structural protein coding genomic regions. In 2015, a novel GII.P16-GII.4 Sydney recombinant strain emerged, replacing the predominance of GII.Pe-GII.4 Sydney among US outbreaks. Distinct from GII.P16 polymerases detected since 2010, this novel GII.P16 was subsequently detected among GII.1, GII.2, GII.3, GII.10 and GII.12 viruses, prompting an investigation on the unique characteristics of these viruses. Norovirus positive samples (n = 1807) were dual-typed, of which a subset (n = 124) was sequenced to yield near-complete genomes. CaliciNet and National Outbreak Reporting System (NORS) records were matched to link outbreak characteristics and case outcomes to molecular data and GenBank was mined for contextualization. Recombination with the novel GII.P16 polymerase extended GII.4 Sydney predominance and increased the number of GII.2 outbreaks in the US. Introduction of the novel GII.P16 noroviruses occurred without unique amino acid changes in VP1, more severe case outcomes, or differences in affected population. However, unique changes were found among NS1/2, NS4 and VP2 proteins, which have immune antagonistic functions, and the RdRp. Multiple polymerase-capsid combinations were detected among GII viruses including 11 involving GII.P16. Molecular surveillance of protein sequences from norovirus genomes can inform the functional importance of amino acid changes in emerging recombinant viruses and aid in vaccine and antiviral formulation.

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