scholarly journals Deep mutational scanning comprehensively maps how Zika envelope protein mutations affect viral growth and antibody escape

2019 ◽  
Author(s):  
Marion Sourisseau ◽  
Daniel J.P. Lawrence ◽  
Megan C. Schwarz ◽  
Carina H. Storrs ◽  
Ethan C. Veit ◽  
...  

AbstractFunctional constraints on viral proteins are often assessed by examining sequence conservation among natural strains, but this approach is relatively ineffective for Zika virus because all known sequences are highly similar. Here we take an alternative approach to map functional constraints on Zika virus’s envelope (E) protein by using deep mutational scanning to measure how all amino-acid mutations to the protein affect viral growth in cell culture. The resulting sequence-function map is consistent with existing knowledge about E protein structure and function, but also provides insight into mutation-level constraints in many regions of the protein that have not been well characterized in prior functional work. In addition, we extend our approach to completely map how mutations affect viral neutralization by two monoclonal antibodies, thereby precisely defining their functional epitopes. Overall, our study provides a valuable resource for understanding the effects of mutations to this important viral protein, and also offers a roadmap for future work to map functional and antigenic selection to Zika virus at high resolution.ImportanceZika virus has recently been shown to be associated with severe birth defects. The virus’s E protein mediates its ability to infect cells, and is also the primary target of the antibodies that are elicited by natural infection and vaccines that are being developed against the virus. Therefore, determining the effects of mutations to this protein is important for understanding its function, its susceptibility to vaccine-mediated immunity, and its potential for future evolution. We completely mapped how amino-acid mutations to E protein affected the virus’s ability to grow in cells in the lab and escape from several antibodies. The resulting maps relate changes in the E protein’s sequence to changes in viral function, and therefore provide a valuable complement to existing maps of the physical structure of the protein.

2019 ◽  
Vol 93 (23) ◽  
Author(s):  
Marion Sourisseau ◽  
Daniel J. P. Lawrence ◽  
Megan C. Schwarz ◽  
Carina H. Storrs ◽  
Ethan C. Veit ◽  
...  

ABSTRACT Functional constraints on viral proteins are often assessed by examining sequence conservation among natural strains, but this approach is relatively ineffective for Zika virus because all known sequences are highly similar. Here, we take an alternative approach to map functional constraints on Zika virus’s envelope (E) protein by using deep mutational scanning to measure how all amino acid mutations to the E protein affect viral growth in cell culture. The resulting sequence-function map is consistent with existing knowledge about E protein structure and function but also provides insight into mutation-level constraints in many regions of the protein that have not been well characterized in prior functional work. In addition, we extend our approach to completely map how mutations affect viral neutralization by two monoclonal antibodies, thereby precisely defining their functional epitopes. Overall, our study provides a valuable resource for understanding the effects of mutations to this important viral protein and also offers a roadmap for future work to map functional and antigenic selection to Zika virus at high resolution. IMPORTANCE Zika virus has recently been shown to be associated with severe birth defects. The virus’s E protein mediates its ability to infect cells and is also the primary target of the antibodies that are elicited by natural infection and vaccines that are being developed against the virus. Therefore, determining the effects of mutations to this protein is important for understanding its function, its susceptibility to vaccine-mediated immunity, and its potential for future evolution. We completely mapped how amino acid mutations to the E protein affected the virus’s ability to grow in cells in the laboratory and escape from several antibodies. The resulting maps relate changes in the E protein’s sequence to changes in viral function and therefore provide a valuable complement to existing maps of the physical structure of the protein.


Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 93
Author(s):  
Marion Sourisseau ◽  
Daniel J. P. Lawrence ◽  
Megan C. Schwarz ◽  
Carina H. Storrs ◽  
Ethan C. Veit ◽  
...  

The Zika virus has recently been shown to be associated with severe birth defects. The virus’ envelope (E) protein mediates its ability to infect cells and is also the primary target of the antibodies that are elicited by natural infection and the vaccines that are being developed against the virus. Therefore, determining the effects of mutations on this protein is important for understanding its function, its susceptibility to vaccine-mediated immunity, and its potential for future evolution. Functional constraints on viral proteins are often assessed by examining sequence conservation among natural strains, but this approach is relatively ineffective for the Zika virus because all known sequences are highly similar. Here, we take an alternative approach to mapping functional constraints on Zika virus’ E protein by using deep mutational scanning to measure how all amino-acid mutations in the protein affect viral growth in cell culture. The resulting sequence-function map is consistent with the existing knowledge about E protein structure and function but also provides insight into mutation-level constraints in many regions of the protein that have not been well characterized in prior functional work. In addition, we extend our approach to completely map how mutations affect viral neutralization by two monoclonal antibodies, thereby precisely defining their functional epitopes. Overall, our study provides a valuable resource for understanding the effects of mutations on this important viral protein and also offers a roadmap for future work to map functional and antigenic selection to the Zika virus at high resolution.


2020 ◽  
Vol 94 (20) ◽  
Author(s):  
Derek L. Carbaugh ◽  
Shuntai Zhou ◽  
Wes Sanders ◽  
Nathaniel J. Moorman ◽  
Ronald Swanstrom ◽  
...  

ABSTRACT Recent Zika virus (ZIKV) outbreaks and unexpected clinical manifestations of ZIKV infection have prompted an increase in ZIKV-related research. Here, we identify two strain-specific determinants of ZIKV virulence in mice. We found that strain H/PF/2013 caused 100% lethality in Ifnar1−/− mice, whereas PRVABC59 caused no lethality; both strains caused 100% lethality in Ifnar1−/− Ifngr1−/− double-knockout (DKO) mice. Deep sequencing revealed a high-frequency variant in PRVABC59 not present in H/PF/2013: a G-to-T change at nucleotide 1965 producing a Val-to-Leu substitution at position 330 of the viral envelope (E) protein. We show that the V330 variant is lethal on both virus strain backgrounds, whereas the L330 variant is attenuating only on the PRVABC59 background. These results identify a balanced polymorphism in the E protein that is sufficient to attenuate the PRVABC59 strain but not H/PF/2013. The consensus sequences of H/PF/2013 and PRVABC59 differ by 3 amino acids, but these were not responsible for the difference in virulence between the two strains. H/PF/2013 and PRVABC59 differ by an additional 31 noncoding or silent nucleotide changes. We made a panel of chimeric viruses with identical amino acid sequences but nucleotide sequences derived from H/PF/2013 or PRVABC59. We found that 6 nucleotide differences in the 3′ quarter of the H/PF/2013 genome were sufficient to confer virulence in Ifnar1−/− mice. Altogether, our work identifies a large and previously unreported difference in virulence between two commonly used ZIKV strains, in two widely used mouse models of ZIKV pathogenesis (Ifnar1−/− and Ifnar1−/− Ifngr1−/− DKO mice). IMPORTANCE Contemporary ZIKV strains are closely related and often used interchangeably in laboratory research. Here, we identify two strain-specific determinants of ZIKV virulence that are evident in only Ifnar1−/− mice but not Ifnar1−/− Ifngr1−/− DKO mice. These results identify a balanced polymorphism in the E protein that is sufficient to attenuate the PRVABC59 strain but not H/PF/2013. We further identify a second virulence determinant in the H/PF/2013 strain, which is driven by the viral nucleotide sequence but not the amino acid sequence. Altogether, our work identifies a large and previously unreported difference in virulence between two commonly used ZIKV strains, in two widely used mouse models of ZIKV pathogenesis. Our results highlight that even very closely related virus strains can produce significantly different pathogenic phenotypes in common laboratory models.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247266
Author(s):  
Chutchai Piewbang ◽  
Sabrina Wahyu Wardhani ◽  
Jira Chanseanroj ◽  
Jakarwan Yostawonkul ◽  
Suwimon Boonrungsiman ◽  
...  

Carnivore protoparvovirus-1 (CPPV-1), a viral species containing feline panleukopenia virus (FPV) and canine parvovirus (CPV) variants, are widely spread among domestic and wild carnivores causing systemic fatal diseases. Wild fishing cats (Prionailurus viverrinus), a globally vulnerable species, have been found dead. Postmortem examination of the carcasses revealed lesions in intestine, spleen and kidney. CPPV-1 antigen identification in these tissues, using polymerase chain reaction (PCR) and immunohistochemistry (IHC), supported the infection by the virus. PCR- and IHC-positivity in kidney tissues revealed atypical localization of the virus while in situ hybridization (ISH) and transmission electron microscopy (TEM) with the pop-off technique confirmed the first description of viral localization in kidneys. Complete genome characterization and deduced amino acid analysis of the obtained CPPV-1 from the fishing cats revealed FPV as a causative agent. The detected FPV sequences showed amino acid mutations at I566M and M569R in the capsid protein. Phylogenetic and evolutionary analyses of complete coding genome sequences revealed that the fishing cat CPPV-1 genomes are genetically clustered to the FPV genomes isolated from domestic cats in Thailand. Since the 1970s, these genomes have also been shown to share a genetic evolution with Chinese FPV strains. This study is the first evidence of CPPV-1 infection in fishing cats and it is the first to show its localization in the kidneys. These findings support the multi-host range of this parvovirus and suggest fatal CPPV-1 infections may result in other vulnerable wild carnivores.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Hugh K Haddox ◽  
Adam S Dingens ◽  
Sarah K Hilton ◽  
Julie Overbaugh ◽  
Jesse D Bloom

The immediate evolutionary space accessible to HIV is largely determined by how single amino acid mutations affect fitness. These mutational effects can shift as the virus evolves. However, the prevalence of such shifts in mutational effects remains unclear. Here, we quantify the effects on viral growth of all amino acid mutations to two HIV envelope (Env) proteins that differ at>100 residues. Most mutations similarly affect both Envs, but the amino acid preferences of a minority of sites have clearly shifted. These shifted sites usually prefer a specific amino acid in one Env, but tolerate many amino acids in the other. Surprisingly, shifts are only slightly enriched at sites that have substituted between the Envs—and many occur at residues that do not even contact substitutions. Therefore, long-range epistasis can unpredictably shift Env’s mutational tolerance during HIV evolution, although the amino acid preferences of most sites are conserved between moderately diverged viral strains.


2018 ◽  
Author(s):  
Juhye M. Lee ◽  
John Huddleston ◽  
Michael B. Doud ◽  
Kathryn A. Hooper ◽  
Nicholas C. Wu ◽  
...  

Human influenza virus rapidly accumulates mutations in its major surface protein hemagglutinin (HA). The evolutionary success of influenza virus lineages depends on how these mutations affect HA’s functionality and antigenicity. Here we experimentally measure the effects on viral growth in cell culture of all single amino-acid mutations to the HA from a recent human H3N2 influenza virus strain. We show that mutations that are measured to be more favorable for viral growth are enriched in evolutionarily successful H3N2 viral lineages relative to mutations that are measured to be less favorable for viral growth. Therefore, despite the well-known caveats about cell-culture measurements of viral fitness, such measurements can still be informative for understanding evolution in nature. We also compare our measurements for H3 HA to similar data previously generated for a distantly related H1 HA, and find substantial differences in which amino acids are preferred at many sites. For instance, the H3 HA has less disparity in mutational tolerance between the head and stalk domains than the H1 HA. Overall, our work suggests that experimental measurements of mutational effects can be leveraged to help understand the evolutionary fates of viral lineages in nature — but only when the measurements are made on a viral strain similar to the ones being studied in nature.Significance StatementA key goal in the study of influenza virus evolution is to forecast which viral strains will persist and which ones will die out. Here we experimentally measure the effects of all amino-acid mutations to the hemagglutinin protein from a human H3N2 influenza strain on viral growth in cell culture. We show that these measurements have utility for distinguishing among viral strains that do and do not succeed in nature. Overall, our work suggests that new high-throughput experimental approaches may be useful for understanding virus evolution in nature.


2017 ◽  
Author(s):  
Hugh K. Haddox ◽  
Adam S. Dingens ◽  
Sarah K. Hilton ◽  
Julie Overbaugh ◽  
Jesse D. Bloom

AbstractThe immediate evolutionary space accessible to HIV is largely determined by how single amino-acid mutations affect fitness. These mutational effects can shift as the virus evolves. However, the prevalence of such shifts in mutational effects remains unclear. Here we quantify the effects on viral growth of all amino-acid mutations to two HIV envelope (Env) proteins that differ at >100 residues. Most mutations similarly affect both Envs, but the amino-acid preferences of a minority of sites have clearly shifted. These shifted sites usually prefer a specific amino acid in one Env, but tolerate many amino acids in the other. Surprisingly, shifts are only slightly enriched at sites that have substituted between the Envs -- and many occur at residues that do not even contact substitutions. Therefore, long-range epistasis can unpredictably shift Env's mutational tolerance during HIV evolution, although the amino-acid preferences of most sites are conserved between moderately diverged viral strains.


2021 ◽  
Vol 294 ◽  
pp. 198290
Author(s):  
Lidia A. Baltina ◽  
Mann-Jen Hour ◽  
Ya-Chi Liu ◽  
Young-Sheng Chang ◽  
Su-Hua Huang ◽  
...  

2021 ◽  
pp. 1-13
Author(s):  
Salvatore Dimonte ◽  
Muhammed Babakir-Mina ◽  
Taib Hama-Soor ◽  
Salar Ali

<b><i>Introduction:</i></b> SARS-CoV-2 is a new type of coronavirus causing a pandemic severe acute respiratory syndrome (SARS-2). Coronaviruses are very diverting genetically and mutate so often periodically. The natural selection of viral mutations may cause host infection selectivity and infectivity. <b><i>Methods:</i></b> This study was aimed to indicate the diversity between human and animal coronaviruses through finding the rate of mutation in each of the spike, nucleocapsid, envelope, and membrane proteins. <b><i>Results:</i></b> The mutation rate is abundant in all 4 structural proteins. The most number of statistically significant amino acid mutations were found in spike receptor-binding domain (RBD) which may be because it is responsible for a corresponding receptor binding in a broad range of hosts and host selectivity to infect. Among 17 previously known amino acids which are important for binding of spike to angiotensin-converting enzyme 2 (ACE2) receptor, all of them are conservative among human coronaviruses, but only 3 of them significantly are mutated in animal coronaviruses. A single amino acid aspartate-454, that causes dissociation of the RBD of the spike and ACE2, and F486 which gives the strength of binding with ACE2 remain intact in all coronaviruses. <b><i>Discussion/Conclusion:</i></b> Observations of this study provided evidence of the genetic diversity and rapid evolution of SARS-CoV-2 as well as other human and animal coronaviruses.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Pralow ◽  
Alexander Nikolay ◽  
Arnaud Leon ◽  
Yvonne Genzel ◽  
Erdmann Rapp ◽  
...  

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.


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