Synergistic Effect of the PDZ and p85β-Binding Domains of the NS1 Protein on Virulence of an Avian H5N1 Influenza A Virus

Fan, Shufang; Macken, Catherine A.; Liu, Chengjun; Ozawa, Makoto; Goto, Hideo; Iswahyudi, N. F. N.; Nidom, Chairul A.; Chen, Hualan; Neumann, Gabriele; Kawaoka, Yoshihiro

doi:10.1128/jvi.02608-12

Cited by 51 publications

(52 citation statements)

References 69 publications

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“…These findings suggest that an ancestor of the A(H7N9) PA genes accumulated several amino acid changes that increased its replicative ability in avian cells but decreased its replicative capacity in mammalian systems; nonetheless, A(H7N9) viruses possessing such a mammalian-adapted PA replicate efficiently in mammals. We recently found the same phenomenon for the NS gene of H5N1 highly pathogenic avian influenza viruses (35), which possesses two mutations that synergistically attenuate the H5N1 virulence in mammalian hosts. Collectively, these data indicate that avian influenza virus replication in mammals is associated with mutations that increase (for example, PB2-627K) or decrease (for example, some of the PA mutations tested here) virus replicative ability in mammals; in the latter case, we speculate that the ancestral virus may have been "too aggressive" in mammals.…”

Section: Fig 3 Growth Kinetics Of Mutant Viruses In Vitro A549 (A) Omentioning

confidence: 83%

Virulence-Affecting Amino Acid Changes in the PA Protein of H7N9 Influenza A Viruses

Yamayoshi

Yamada

Fukuyama

et al. 2014

J Virol

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108

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Novel avian-origin influenza A(H7N9) viruses were first reported to infect humans in March 2013. To date, 143 human cases, including 45 deaths, have been recorded. By using sequence comparisons and phylogenetic and ancestral inference analyses, we identified several distinct amino acids in the A(H7N9) polymerase PA protein, some of which may be mammalian adapting. Mutant viruses possessing some of these amino acid changes, singly or in combination, were assessed for their polymerase activities and growth kinetics in mammalian and avian cells and for their virulence in mice. We identified several mutants that were slightly more virulent in mice than the wild-type A(H7N9) virus, A/Anhui/1/2013. These mutants also exhibited increased polymerase activity in human cells but not in avian cells. Our findings indicate that the PA protein of A(H7N9) viruses has several amino acid substitutions that are attenuating in mammals. (1). To date, 143 confirmed cases of A(H7N9) virus infection and 45 associated deaths have been reported. This represents a case-fatality rate of ca. 31.5%; however, this rate may actually be lower because the number of mild cases is unknown (2). Phylogenetic analysis has revealed that the hemagglutinin (HA) and neuraminidase (NA) genes of the A(H7N9) viruses share the greatest sequence identities with Eurasian avian A(H7N3) viruses and N9 viruses of different HA subtypes, respectively (3-6). The other six viral genes are highly related to A(H9N2) viruses that have circulated in poultry in China (1, 3-7). These findings indicate that A(H7N9) viruses are reassortant viruses with genes from several avian isolates. IMPORTANCE Novel avian-origin influenzaWe (8) and others (9-14) recently reported that prototype A(H7N9) viruses replicate efficiently in mammalian cells, mice, and ferrets, and transmit among subsets of pairs of ferrets. A(H7N9) viruses isolated from humans possess several amino acid changes already known to facilitate infection of mammals, including leucine at position 226 of HA (H3 HA numbering), which confers increased binding to human-type receptors (15), and lysine at position 627 (PB2-627K) (16,17) and asparagine at position 701 (PB2-701N) (18,19) in the polymerase protein PB2, which increase the polymerase activity in mammalian cells. Notably, the PB2-627K and PB2-701N markers have been detected in almost all human, but not avian or environmental, A(H7N9) isolates (6).In addition to the known mammalian-adapting amino acid changes in the PB2 and HA proteins, additional amino acid changes in A(H7N9) proteins may have enabled these viruses to infect mammals. We therefore undertook a comprehensive analysis of A(H7N9) sequences and identified several amino acids in the polymerase PA protein that are typically found in human (but not avian) influenza A viruses or are characteristic of A(H7N9) viruses (i.e., not commonly detected among human or avian influenza viruses). Here, we evaluated these distinguishing amino acid changes in vivo and in vitro. Cells. Madin-Darby canine kidney ...

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Section: Fig 3 Growth Kinetics Of Mutant Viruses In Vitro A549 (A) Omentioning

confidence: 83%

Virulence-Affecting Amino Acid Changes in the PA Protein of H7N9 Influenza A Viruses

Yamayoshi

Yamada

Fukuyama

et al. 2014

J Virol

Self Cite

108

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“…The NS1 protein of 9UO025, 9UO036 and 9UO139 displayed a mutation of S42A, which has been associated with an increase in virulence in chickens and mice [52]. In all of the H5N2 isolates in this study, the PDZ binding sequence at the C-terminus of the NS1 protein was ESEV and the residue at position 138 was Phe (F), suggesting increased virulence in mammals [33,53]. In addition to the mutation in the NS1 gene, the mutation N66S, associated with increased virulence of influenza A viruses in mice [54], was found in the PB1-F2 gene of two isolates (9UO036 and 9UO139).…”

Section: Discussionmentioning

confidence: 99%

Genetic characterization of H5N2 influenza viruses isolated from wild birds in Japan suggests multiple reassortment

et al. 2016

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Low-pathogenic avian influenza viruses (LPAIVs) of the H5 subtype can mutate to highly pathogenic forms, potentially destabilizing the poultry industry. Wild migratory birds are considered a natural reservoir of LPAIVs capable of dispersing both high-and low-pathogenic forms of the virus. Therefore, surveillance and characterization of AIV in wild birds are essential. Here, we report on the isolation and genetic characterization of 10 AIVs of the H5N2 subtype obtained through surveillance in Hokkaido, Japan, during 2009 and 2011. Fullgenome sequencing revealed that the H5 and N2 genes of these isolates are all closely related to each other, belonging to the Eurasian avian-like lineage, but they are unrelated to H5 highly pathogenic strains of clade 2.3.4.4. The internal genes of the isolates were found to be diverse, consistent with our hypothesis that these H5N2 strains have undergone multiple reassortment events. Even though all of the H5N2 isolates were characterized as LPAIV based on the amino acid sequences at the HA cleavage site, this analysis demonstrates a diverse pool of precursors that may seed future outbreaks in poultry and possible human transmissions, suggesting the need for high-quality surveillance.

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“…PDZ domain-containing proteins play important roles in the transportation, localization and assembly of supramolecular signalling complexes, organizing cell polarity, receptors and downstream effectors (Javier & Rice, 2011;Sheng & Sala, 2001). The PDZ domain has been decribed as a virulence determinant of influenza virus in different animal models; however, this was recognized as a species-specific or strain-specific virulence domain (Fan et al, 2013;Soubies et al, 2010Soubies et al, , 2013Zielecki et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies reported that influenza viruses with C-terminally truncated NS1 proteins of 73, 99 or 126 aa induced higher levels of IFN than viruses with full-length NS1 proteins and were correspondingly more attenuated in mice and pigs (Kochs et al, 2009;Richt & García-Sastre, 2009;Soló rzano et al, 2005). Many previous studies focused on the effect of NS1 in H5N1, H7N1 and WSN H1N1 (a mouse adapted strain of the influenza virus) (Fan et al, 2013;Jackson et al, 2008;Soubies et al, 2010Soubies et al, , 2013Zielecki et al, 2010); however, the biological role of C-terminally truncated NS1 proteins in the virulence and pathogenesis of H9N2 influenza virus has not yet been studied in detail.…”

Section: Introductionmentioning

confidence: 99%

C-terminal elongation of NS1 of H9N2 influenza virus induces a high level of inflammatory cytokines and increases transmission

Kong

Liu

Wang

et al. 2015

Journal of General Virology

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H9N2 avian influenza viruses are enzootic around the world and can infect many different avian and mammalian hosts, including humans. Unlike the H9N2 viruses, which mainly originated in other countries and possess a non-structural protein 1 (NS1) of 230 aa, 98 % of the H9N2 viruses isolated in China lack the 13 aa at the C terminus of NS1 (217 aa in total). The biological significance of NS1 elongation remains elusive. To examine the effect of NS1 C-terminal elongation in the influenza virus, we used reverse genetics to generate a wt avian influenza H9N2 virus containing a 217 aa NS1 (H9N2 NS1217 ) and two mutant viruses with elongated NS1s of 230 and 237 aa (H9N2 NS1230 and H9N2 NS1237 ). C-terminal elongation of NS1 did not have a significant impact on virus replication in Madin-Darby canine kidney cells or DF-1 cells. The three variants exhibited similar replicability in mice; however, the H9N2 NS1230 and H9N2 NS1237 variants exhibited an upregulation in the level of inflammatory cytokines. In addition, both the H9N2 NS1230 and H9N2 NS1237 viruses increased replication and induced a high level of inflammatory cytokines and transmission in chickens, compared with the wt virus. These findings suggest that the NS1 extension conferred a gain of fitness to some extent.

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Synergistic Effect of the PDZ and p85β-Binding Domains of the NS1 Protein on Virulence of an Avian H5N1 Influenza A Virus

Cited by 51 publications

References 69 publications

Virulence-Affecting Amino Acid Changes in the PA Protein of H7N9 Influenza A Viruses

Virulence-Affecting Amino Acid Changes in the PA Protein of H7N9 Influenza A Viruses

Genetic characterization of H5N2 influenza viruses isolated from wild birds in Japan suggests multiple reassortment

C-terminal elongation of NS1 of H9N2 influenza virus induces a high level of inflammatory cytokines and increases transmission

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