Low Polymerase Activity Attributed to PA Drives the Acquisition of the PB2 E627K Mutation of H7N9 Avian Influenza Virus in Mammals

Liu, Liang; Li, Jiang; Li, Junping; Zhao, Qin; Wang, Jinguang; He, Xijun; Huang, Shanyu; Wang, Qian; Zhao, Yuhui; Wang, Guangwen; Sun, Nan; Deng, Guohua; Shi, Jianzhong; Tian, Guobin; Zeng, Xianying; Jiang, Yongping; Liu, Liling; Liu, Jinxiong; Chen, Pucheng; Bu, Zhigao; Kawaoka, Yoshihiro; Chen, Hualan; Liu, Chengjun

doi:10.1128/mbio.01162-19

Cited by 60 publications

(50 citation statements)

References 59 publications

(89 reference statements)

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“…ANP32A and ANP32B proteins from most mammals do not support avian influenza polymerase activity, providing a host barrier against avian influenza virus interspecies transmission. Furthermore, huANP32A has been proposed as being involved in the emergence of the adaptive mutation PB2 E627K in the H7N9 virus strain [65]. In this study, we show that swANP32A, as well as other ANP32A from different species including A B C Empty vector huANP32A swANP32A…”

Section: Discussionmentioning

confidence: 52%

A unique feature of swine ANP32A provides susceptibility to avian influenza virus infection in pigs

Zhang

Wang

et al. 2020

PLoS Pathog

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Both the replication and transcription of the influenza virus are catalyzed by the viral polymerase complex. The polymerases of most avian influenza A viruses have poor performance in mammalian cells, which is considered to be one of the important species barriers. Pigs have been long considered as important intermediate hosts for interspecies transmission of the avian influenza virus, because of their susceptibility to infection with both avian and mammalian influenza viruses. However, the molecular basis of influenza polymerase adaptation in pigs remains largely unknown. ANP32A and ANP32B proteins have been identified as playing fundamental roles in influenza virus replication and host range determination. In this study, we found that swine ANP32A (swANP32A), unlike swine ANP32B or other mammalian ANP32A or B, shows stronger supporting activity to avian viral polymerase. Knockout of ANP32A in pig cells PK15 dramatically reduced avian influenza polymerase activity and viral infectivity, suggesting a unique feature of swANP32A in supporting avian influenza viral polymerase. This species-specific activity is mapped to two key sites, 106V and 156S, in swANP32A. Interestingly, the amino acid 106V is unique to pigs among all the vertebrate species studied, and when combined with 156S, exhibits positive epistasis in pigs. Mutation of 106V and 156S to the signature found in ANP32As from other mammalian species weakened the interaction between swANP32A and chicken viral polymerase, and reduced polymerase activity. Understanding the molecular basis of ANP32 proteins may help to discover new antiviral targets and design avian influenza resistant genome edited pigs.

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Section: Discussionmentioning

confidence: 52%

A unique feature of swine ANP32A provides susceptibility to avian influenza virus infection in pigs

Zhang

Wang

et al. 2020

PLoS Pathog

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“…Influenza viruses easily mutate during their replication in nature. A series of mammalian-host-adapted mutations in PB2 and HA have been reported to dramatically increase the replication, virulence, or transmissibility of avian influenza viruses in mammals (12)(13)(14)(59)(60)(61)(62)(63)(64)(65)(66). We compared the NP sequences of 58,747 viruses that are in public databases and we found different amino acids present at positions 286 and 437 of NP, although amino acids 286A and 437T of NP were the predominant residues; 41,193 viruses have 286A and 58,658 viruses have 437T in their NP (see Table S1 in the supplemental material).…”

Section: Discussionmentioning

confidence: 99%

Amino Acid Mutations A286V and T437M in the Nucleoprotein Attenuate H7N9 Viruses in Mice

Zhang

Shi

et al. 2020

J Virol

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The low-pathogenic H7N9 influenza viruses that emerged in 2013 acquired an insertion of four amino acids in their hemagglutinin cleavage site and thereby became highly pathogenic to chickens in 2017. Previous studies indicated that these highly pathogenic H7N9 viruses are virulent in chickens but have distinct pathotypes in mice. A/chicken/Guangdong/SD098/2017 (CK/SD098) is avirulent, with a 50% mouse lethal dose (MLD50) of >7.5 log10 50% egg infectious dose (EID50), whereas A/chicken/Hunan/S1220/2017 (CK/S1220) is virulent in mice, with an MLD50 of 3.2 log10 EID50. In this study, we explored the genetic determinants that contribute to the difference in virulence between these two H7N9 viruses by generating a series of reassortants and mutants in the CK/S1220 virus background and testing their virulence in mice. We found that the reassortant CK/1220-SD098-NP, carrying the nucleoprotein (NP) of CK/SD098, was avirulent in mice, with an MLD50 of >107.5 EID50. The NPs of these two viruses differ by two amino acids, at positions 286 and 437. We further demonstrated that the amino acid mutations A286V and T437M of NP independently slowed the process of NP import to and export from the nucleus and thus jointly impaired the viral life cycle and attenuated the virulence of these H7N9 viruses in mice. Our study identified new virulence determinants in NP and provided novel targets for the development of live attenuated vaccines and antiviral drugs against influenza viruses. IMPORTANCE The H7N9 influenza viruses that emerged in China in 2013 have caused over 1,500 human infections, with a mortality rate of nearly 40%. The viruses were initially low pathogenic but became highly pathogenic in chickens at the beginning of 2017 and caused severe disease outbreaks in poultry. Several studies suggested that the highly pathogenic H7N9 viruses have increased virulence in mammals; however, the genetic basis of the virulence of H7N9 viruses in mammals is not fully understood. Here, we found that two amino acids, 286A and 437T, in NP are prerequisites for the virulence of H7N9 viruses in mice and the mutations A286V and T437M collectively eliminate the virulence of H7N9 viruses in mice. Our study further demonstrated that the virulence of influenza viruses is a polygenic trait, and the newly identified virulence-related residues in NP may provide new targets for attenuated influenza vaccine and antiviral drug development.

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“…There, using specific siRNAs, ANP32A and ANP32B were required for high human-type (PB2 627K) polymerase activity (10). However, more recently, these findings were challenged by two additional studies reporting that PB2 627K mammalian-adapted IAV replicate efficiently in human ANP32A knockout cells (13,26). In the study by Staller et al the authors further show that an aspartate at position 130 is associated with the species dependent ability of ANP32 proteins to promote mammalian-type IAV polymerase activity and replication in human cells (13).…”

Section: Discussionmentioning

confidence: 99%

ANP32B Deficiency Protects Mice From Lethal Influenza A Virus Challenge by Dampening the Host Immune Response

et al. 2020

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Deciphering complex virus-host interactions is crucial for pandemic preparedness. In this study, we assessed the impact of recently postulated cellular factors ANP32A and ANP32B of influenza A virus (IAV) species specificity on viral pathogenesis in a genetically modified mouse model. Infection of ANP32A −/− and ANP32A +/+ mice with a seasonal H3N2 IAV or a highly pathogenic H5N1 human isolate did not result in any significant differences in virus tropism, innate immune response or disease outcome. However, infection of ANP32B −/− mice with H3N2 or H5N1 IAV revealed significantly reduced virus loads, inflammatory cytokine response and reduced pathogenicity compared to ANP32B +/+ mice. Genome-wide transcriptome analyses in ANP32B +/+ and ANP32B −/− mice further uncovered novel immune-regulatory pathways that correlate with reduced pathogenicity in the absence of ANP32B. These data show that ANP32B but not ANP32A promotes IAV pathogenesis in mice. Moreover, ANP32B might possess a yet unknown immune-modulatory function during IAV infection. Targeting ANP32B or its regulated pathways might therefore pose a new strategy to combat severe influenza.

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Low Polymerase Activity Attributed to PA Drives the Acquisition of the PB2 E627K Mutation of H7N9 Avian Influenza Virus in Mammals

Cited by 60 publications

References 59 publications

A unique feature of swine ANP32A provides susceptibility to avian influenza virus infection in pigs

A unique feature of swine ANP32A provides susceptibility to avian influenza virus infection in pigs

Amino Acid Mutations A286V and T437M in the Nucleoprotein Attenuate H7N9 Viruses in Mice

ANP32B Deficiency Protects Mice From Lethal Influenza A Virus Challenge by Dampening the Host Immune Response

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