scholarly journals Amino Acid Substitutions in Positions 385 and 393 of the Hydrophobic Region of VP4 May Be Associated with Rotavirus Attenuation and Cell Culture Adaptation

Viruses ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 408
Author(s):  
Yusheng Guo ◽  
David E. Wentworth ◽  
Karla M. Stucker ◽  
Rebecca A. Halpin ◽  
Ham Ching Lam ◽  
...  
Keyword(s):  
Cell Culture ◽  
Amino Acid ◽  
Reverse Genetics ◽  
Vaccine Development ◽  
Nonsynonymous Substitution ◽  
Amino Acid Substitutions ◽  
Viral Gastroenteritis ◽  
Hydrophobic Region ◽  
Hydrophobic Domain ◽  
Underlying Mechanisms

Rotaviruses (RVs) are the leading cause of the acute viral gastroenteritis in young children and livestock animals worldwide. Although live attenuated vaccines have been applied to control RV infection for many years, the underlying mechanisms of RV attenuation following cell culture adaption are unknown. To study these mechanisms at the genomic level, we have sequenced and conducted a comparative analysis of two virulent human (Wa, G1P[8] and M, G3P[8]) and two virulent porcine (Gottfried, G4P[6] and OSU, G5P[7]) RV strains maintained in gnotobiotic piglets for 22, 11, 12 and 9 serial passages, respectively, with their attenuated counterparts serially passaged in MA-104 cell cultures for 25, 43, 54 and 43 passages, respectively. We showed that most of the mutations were clustered in the VP4 gene, with a relatively high nonsynonymous substitution rate (81.2%). Moreover, two amino acid substitutions observed in the VP4 gene were conserved between two or more strain pairs. D385N substitution was found in M, Wa and Gottfried strains, and another one, S471H/L was present in Wa and Gottfried strains. Importantly, D385 was reported previously in another study and may be involved in regulation of virus entry. Of interest, although no 385 substitution was found in OSU strains, the attenuated OSU strain contained a unique D393H substitution within the same VP4 hydrophobic domain. Collectively, our data suggest that the VP4 hydrophobic region may play an important role in RV attenuation and aa385 and aa393 may represent potential targets for RV vaccine development using reverse genetics and site-specific mutagenesis.

scholarly journals A Single Point Mutation, Asn16→Lys, Dictates the Temperature-Sensitivity of the Reovirus tsG453 Mutant

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 289
Author(s):  
Kathleen K. M. Glover ◽  
Danica M. Sutherland ◽  
Terence S. Dermody ◽  
Kevin M. Coombs
Keyword(s):  
Amino Acid ◽  
Temperature Sensitivity ◽  
Reverse Genetics ◽  
Core Protein ◽  
Single Point ◽  
Single Amino Acid ◽  
Single Point Mutation ◽  
Temperature Sensitive ◽  
Amino Acid Substitutions ◽  
Gene Encoding

Studies of conditionally lethal mutants can help delineate the structure-function relationships of biomolecules. Temperature-sensitive (ts) mammalian reovirus (MRV) mutants were isolated and characterized many years ago. Two of the most well-defined MRV ts mutants are tsC447, which contains mutations in the S2 gene encoding viral core protein σ2, and tsG453, which contains mutations in the S4 gene encoding major outer-capsid protein σ3. Because many MRV ts mutants, including both tsC447 and tsG453, encode multiple amino acid substitutions, the specific amino acid substitutions responsible for the ts phenotype are unknown. We used reverse genetics to recover recombinant reoviruses containing the single amino acid polymorphisms present in ts mutants tsC447 and tsG453 and assessed the recombinant viruses for temperature-sensitivity by efficiency-of-plating assays. Of the three amino acid substitutions in the tsG453 S4 gene, Asn16-Lys was solely responsible for the tsG453ts phenotype. Additionally, the mutant tsC447 Ala188-Val mutation did not induce a temperature-sensitive phenotype. This study is the first to employ reverse genetics to identify the dominant amino acid substitutions responsible for the tsC447 and tsG453 mutations and relate these substitutions to respective phenotypes. Further studies of other MRV ts mutants are warranted to define the sequence polymorphisms responsible for temperature sensitivity.

scholarly journals Generation of Recombinant Rotavirus with an Antigenic Mosaic of Cross-Reactive Neutralization Epitopes on VP4

2008 ◽  
Vol 82 (13) ◽  
pp. 6753-6757 ◽  
Author(s):  
Satoshi Komoto ◽  
Masanori Kugita ◽  
Jun Sasaki ◽  
Koki Taniguchi
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Amino Acid ◽  
Reverse Genetics ◽  
Amino Acid Substitutions ◽  
Neutralization Epitope ◽  
First Report ◽  
P Type

ABSTRACT Recombinant rotavirus (RV) with cDNA-derived chimeric VP4 was generated using recently developed reverse genetics for RV. The rescued virus, KU//rVP4(SA11)-II(DS-1), contains SA11 (simian RV strain, G3P[2])-based VP4, in which a cross-reactive neutralization epitope (amino acids 381 to 401) on VP5* is replaced by the corresponding sequence of a different P-type DS-1 (human RV strain, G2P[4]). Serological analyses with a panel of anti-VP4- and -VP7-neutralizing monoclonal antibodies revealed that the rescued virus carries a novel antigenic mosaic of cross-reactive neutralization epitopes on its VP4 surface. This is the first report of the generation of a recombinant RV with artificial amino acid substitutions.

scholarly journals Mechanism of Cell Culture Adaptation of an Enteric Calicivirus, the Porcine Sapovirus Cowden Strain

2015 ◽  
Vol 90 (3) ◽  
pp. 1345-1358 ◽  
Author(s):  
Zhongyan Lu ◽  
Masaru Yokoyama ◽  
Ning Chen ◽  
Tomoichiro Oka ◽  
Kwonil Jung ◽  
...  
Keyword(s):  
Cell Culture ◽  
Tissue Culture ◽  
Amino Acid ◽  
Virus Replication ◽  
Amino Acid Substitutions ◽  
Virus Binding ◽  
Culture Adaptation ◽  
Porcine Sapovirus ◽  
Cowden Strain

ABSTRACTThe porcine sapovirus (SaV) (PoSaV) Cowden strain is one of only a few culturable enteric caliciviruses. Compared to the wild-type (WT) PoSaV Cowden strain, tissue culture-adapted (TC) PoSaV has two conserved amino acid substitutions in the RNA-dependent RNA polymerase (RdRp) and six in the capsid protein (VP1). By using the reverse-genetics system, we identified that 4 amino acid substitutions in VP1 (residues 178, 289, 324, and 328), but not the substitutions in the RdRp region, were critical for the cell culture adaptation of the PoSaV Cowden strain. The other two substitutions in VP1 (residues 291 and 295) reduced virus replicationin vitro. Three-dimensional (3D) structural analysis of VP1 showed that residue 178 was located near the dimer-dimer interface, which may affect VP1 assembly and oligomerization; residues 289, 291, 324, and 328 were located at protruding subdomain 2 (P2) of VP1, which may influence virus binding to cellular receptors; and residue 295 was located at the interface of two monomeric VP1 proteins, which may influence VP1 dimerization. Although reversion of the mutation at residue 291 or 295 from that of the TC strain to that of the WT reduced virus replicationin vitro, it enhanced virus replicationin vivo, and the revertants induced higher-level serum and mucosal antibody responses than those induced by the TC PoSaV Cowden strain. Our findings reveal the molecular basis for PoSaV adaptation to cell culture. These findings may provide new, critical information for the cell culture adaptation of other PoSaV strains and human SaVs or noroviruses.IMPORTANCEThe tissue culture-adapted porcine sapovirus Cowden strain is one of only a few culturable enteric caliciviruses. We discovered that 4 amino acid substitutions in VP1 (residues 178, 289, 324, and 328) were critical for its adaptation to LLC-PK cells. Two substitutions in VP1 (residues 291 and 295) reduced virus replicationin vitrobut enhanced virus replication and induced higher-level serum and mucosal antibody responses in gnotobiotic pigs than those induced by the tissue culture-adapted strain. Structural modeling analysis of VP1 suggested that residue 178 may affect VP1 assembly and oligomerization; residues 289, 291, 324, and 328 may influence virus binding to cellular receptors; and residue 295 may influence VP1 dimerization. Our findings will provide new information for the cell culture adaptation of other sapoviruses and possibly noroviruses.

scholarly journals Adaptive amino acid substitutions enable transmission of an H9N2 avian influenza virus in guinea pigs

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Liu Lina ◽  
Chen Saijuan ◽  
Wang Chengyu ◽  
Lu Yuefeng ◽  
Dong Shishan ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Hong Kong ◽  
Amino Acid ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Reverse Genetics ◽  
Amino Acid Substitutions ◽  
Potential Threat ◽  
Pathogenic Avian Influenza Virus ◽  
The Impact

AbstractH9N2 is the most prevalent low pathogenic avian influenza virus (LPAIV) in domestic poultry in the world. Two distinct H9N2 poultry lineages, G1-like (A/quail/Hong Kong/G1/97) and Y280-like (A/Duck/Hong Kong/Y280/1997) viruses, are usually associated with binding affinity for both α 2,3 and α 2,6 sialic acid receptors (avian and human receptors), raising concern whether these viruses possess pandemic potential. To explore the impact of mouse adaptation on the transmissibility of a Y280-like virus A/Chicken/Hubei/214/2017(H9N2) (abbreviated as WT), we performed serial lung-to-lung passages of the WT virus in mice. The mouse-adapted variant (MA) exhibited enhanced pathogenicity and advantaged transmissibility after passaging in mice. Sequence analysis of the complete genomes of the MA virus revealed a total of 16 amino acid substitutions. These mutations distributed across 7 segments including PB2, PB1, PA, NP, HA, NA and NS1 genes. Furthermore, we generated a panel of recombinant or mutant H9N2 viruses using reverse genetics technology and confirmed that the PB2 gene governing the increased pathogenicity and transmissibility. The combinations of 340 K and 588 V in PB2 were important in determining the altered features. Our findings elucidate the specific mutations in PB2 contribute to the phenotype differences and emphasize the importance of monitoring the identified amino acid substitutions due to their potential threat to human health.

scholarly journals Genetic analysis of the SPRN gene in ruminants reveals polymorphisms in the alanine-rich segment of shadoo protein

2009 ◽  
Vol 90 (10) ◽  
pp. 2575-2580 ◽  
Author(s):  
Paula Stewart ◽  
Cuicui Shen ◽  
Deming Zhao ◽  
Wilfred Goldmann
Keyword(s):  
Amino Acid ◽  
Disease Susceptibility ◽  
Prion Diseases ◽  
Neuroprotective Activity ◽  
Single Amino Acid ◽  
Amino Acid Substitutions ◽  
Human Prion Disease ◽  
Gene Encoding ◽  
Hydrophobic Region ◽  
Sheep Scrapie

Prion diseases in ruminants, especially sheep scrapie, cannot be fully explained by PRNP genetics, suggesting the influence of a second modulator gene. The SPRN gene is a good candidate for this role. The SPRN gene encodes the shadoo protein (Sho) which has homology to the PRNP gene encoding prion protein (PrP). Murine Sho has a similar neuroprotective activity to PrP and SPRN gene variants are associated with human prion disease susceptibility. SPRN gene sequences were obtained from 14 species in the orders Artiodactyla and Rodentia. We report here the sequences of more than 20 different Sho proteins that have arisen due to single amino acid substitutions and amino acid deletions or insertions. All Sho sequences contained an alanine-rich sequence homologous to a hydrophobic region with amyloidogenic characteristics in PrP. In contrast with PrP, the Sho sequence showed variability in the number of alanine residues.

scholarly journals How Did Zika Virus Emerge in the Pacific Islands and Latin America?

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
John H.-O. Pettersson ◽  
Vegard Eldholm ◽  
Stephen J. Seligman ◽  
Åke Lundkvist ◽  
Andrew K. Falconar ◽  
...  
Keyword(s):  
Latin America ◽  
Amino Acid ◽  
Zika Virus ◽  
Reverse Genetics ◽  
Pacific Islands ◽  
Vector Competence ◽  
Phylogenetic Analyses ◽  
Human Populations ◽  
Amino Acid Substitutions ◽  
The Pacific

ABSTRACT The unexpected emergence of Zika virus (ZIKV) in the Pacific Islands and Latin America and its association with congenital Zika virus syndrome (CZVS) (which includes microcephaly) and Guillain-Barré syndrome (GBS) have stimulated wide-ranging research. High densities of susceptible Aedes spp., immunologically naive human populations, global population growth with increased urbanization, and escalation of global transportation of humans and commercial goods carrying vectors and ZIKV undoubtedly enhanced the emergence of ZIKV. However, flavivirus mutations accumulate with time, increasing the likelihood that genetic viral differences are determinants of change in viral phenotype. Based on comparative ZIKV complete genome phylogenetic analyses and temporal estimates, we identify amino acid substitutions that may be associated with increased viral epidemicity, CZVS, and GBS. Reverse genetics, vector competence, and seroepidemiological studies will test our hypothesis that these amino acid substitutions are determinants of epidemic and neurotropic ZIKV emergence.

scholarly journals Degrons at the C Terminus of the Pathogenic but Not the Nonpathogenic Hantavirus G1 Tail Direct Proteasomal Degradation

2007 ◽  
Vol 81 (8) ◽  
pp. 4323-4330 ◽  
Author(s):  
Nandini Sen ◽  
Adrish Sen ◽  
Erich R. Mackow
Keyword(s):  
Amino Acid ◽  
Fluorescent Protein ◽  
Hemorrhagic Fever ◽  
Proteasomal Degradation ◽  
Virulence Determinants ◽  
Hydrophobic Region ◽  
Hydrophobic Domain ◽  
C Terminus ◽  
Hydrophilic Residues ◽  
Green Fluorescent

ABSTRACT Pathogenic hantaviruses cause two human diseases: hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS). The hantavirus G1 protein contains a long, 142-amino-acid cytoplasmic tail, which in NY-1 virus (NY-1V) is ubiquitinated and proteasomally degraded (E. Geimonen, I. Fernandez, I. N. Gavrilovskaya, and E. R. Mackow, J. Virol. 77: 10760-10768, 2003). Here we report that the G1 cytoplasmic tails of pathogenic Andes (HPS) and Hantaan (HFRS) viruses are also degraded by the proteasome and that, in contrast, the G1 tail of nonpathogenic Prospect Hill virus (PHV) is stable and not proteasomally degraded. We determined that the signals which direct NY-1V G1 tail degradation are present in a hydrophobic region within the C-terminal 30 residues of the protein. In contrast to that of PHV, the NY-1V hydrophobic domain directs the proteasomal degradation of green fluorescent protein and constitutes an autonomous degradation signal, or “degron,” within the NY-1V G1 tail. Replacing 4 noncontiguous residues of the NY-1V G1 tail with residues present in the stable PHV G1 tail resulted in a NY-1V G1 tail that was not degraded by the proteasome. In contrast, changing a different but overlapping set of 4 PHV residues to corresponding NY-1V residues directed proteasomal degradation of the PHV G1 tail. The G1 tails of pathogenic, but not nonpathogenic, hantaviruses contain intervening hydrophilic residues within the C-terminal hydrophobic domain, and amino acid substitutions that alter the stability or degradation of NY-1V or PHV G1 tails result from removing or adding intervening hydrophilic residues. Our results identify residues that selectively direct the proteasomal degradation of pathogenic hantavirus G1 tails. Although a role for the proteasomal degradation of the G1 tail in HPS or HFRS is unclear, these findings link G1 tail degradation to viral pathogenesis and suggest that degrons within hantavirus G1 tails are potential virulence determinants.

scholarly journals Regeneration of a recombinant infectious bursal disease virus having four amino acid substitutions in VP2 by reverse genetics

2015 ◽  
Vol 31 (1) ◽  
pp. 12-19
Author(s):  
M Noor ◽  
C Lüken ◽  
PM Das ◽  
MR Islam ◽  
H Müller
Keyword(s):  
Cell Culture ◽  
Amino Acid ◽  
Infectious Bursal Disease Virus ◽  
Recombinant Strain ◽  
Reverse Genetics ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Bursal Disease ◽  
Cloned Cdna

Infectious bursal disease virus (IBDV), a virus with a double-stranded, bi-segmented RNA genome, is an economically important pathogen of chickens. Recent understanding of the molecular biology of IBDV has implicated several amino acid residues in the capsid protein VP2 in pathogenicity and tissue culture adaptation. In the present study a recombinant strain of IBDV having four mutations in VP2 (Gln253His, Asp279Asn, Ala284Thr and Ser330Arg) has been generated using reverse genetics. Desired mutations were introduced in the VP2 gene of the cloned cDNA of genome segment A of a very virulent (vv) IBDV by site-directed mutagenesis. Capped RNA transcribed in vitro from cloned cDNA of the modified segment A and wild type segment B was co-transfected into chicken embryo fibroblast (CEF) cell culture. The recombinant virus, designated as BD- 3tcC, was rescued from the transfected cell culture and characterized in vitro. BD-3tcC retained all the four desired mutations and replicated with titres only slightly lower than those of CEF cell-culture-adapted wild-type IBDV. This recombinant strain can be used in future studies for understanding the biological significance of these four amino acid residues in VP2. DOI: http://dx.doi.org/10.3329/bvet.v31i1.22838 Bangl. vet. 2014. Vol. 31, No. 1, 12-19

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