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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Virology
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1532304

PB2 and PA mutations contribute to the pathogenicity of mouse-adapted pdm H1N1-Venus reporter influenza A virus in mammalian model

Provisionally accepted
Shixiang Wu Shixiang Wu 1Ruonan Yi Ruonan Yi 1Yingying Tao Yingying Tao 1Huimin Wu Huimin Wu 1Li Wu Li Wu 2Jiasheng Song Jiasheng Song 1Xin Zhang Xin Zhang 1Beibei Yang Beibei Yang 1Xing Wu Xing Wu 1Yulong He Yulong He 1Jianhong Shu Jianhong Shu 1Huapeng Feng Huapeng Feng 1*
  • 1 Zhejiang Sci-Tech University, Hangzhou, China
  • 2 China Jiliang University, Hangzhou, Zhejiang Province, China

The final, formatted version of the article will be published soon.

    Influenza A viruses have been a threat to human health since 100 years ago.Understanding the dynamics and pathogenicity of the influenza viruses in vivo is of great value in controlling influenza pandemic. Fluorescent protein carrying recombinant influenza virus is as a substantially useful tool for studying viral characteristic in vivo and high-throughput screening in vitro. In this study, we generated a recombinant pdmH1N1 CA04 influenza virus carrying a Venus reporter gene in the nonstructural(NS)segment by reverse genetics. After we passaged the recombinant influenza virus carrying Venus by lung-to-lung in mice, we found that virulence of the passaged pdmH1N1 CA04-Venus significantly increased and was lethal to the mice.We finally isolated one mouse-adapted pdmH1N1 CA04-Venus with bigger plaques expressing the amount of Venus proteins by using the ninth passage lung homogenate with plague purification. We found three different amino acids (PB2 T340K, PA I21M and F175L) between WT-CA04-Venus and MA-CA04-Venus by whole genome sequencing. Interestingly, the polymerase activity of MA-CA04-Venus was significantly lower than that of WT-CA04-Venus in a mini-genome assay. Further investigation demonstrates that PA I21M and PA I21M+PB2 T340K significantly enhanced the polymerase activity of WT-CA04-Venus, however, PA F175L+PB2 T340K significantly decreased the polymerase activity of MA-CA04-Venus. Therefore, PA I21M mutation may determine the increased virulence in mice and PA F175L+PB2 T340K may be involved in the stability of Venus insertion. Above all, we generated a mouse-adapted pdmH1N1 CA04-Venus virus with high virulence and stable green fluorescent Venus protein. It is a useful tool for high-throughput screening for antiviral drugs and investigating the interaction between the influenza virus and host in vivo.

    Keywords: Reporter influenza virus, mouse-adapted, pdmH1N1 CA04, Venus, stability, PA and PB2

    Received: 21 Nov 2024; Accepted: 16 Dec 2024.

    Copyright: © 2024 Wu, Yi, Tao, Wu, Wu, Song, Zhang, Yang, Wu, He, Shu and Feng. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Huapeng Feng, Zhejiang Sci-Tech University, Hangzhou, China

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