title: Amino acids 473V and 598P of PB1 from an avian-origin influenza A virus contribute to polymerase activity, especially in mammalian cells.
abstract: It has been reported that the avian-origin influenza A virus PB1 protein (avian PB1) enhances influenza A virus polymerase activity in mammalian cells when it replaces the human-origin PB1 protein (human PB1). Characterization of the amino acid residues that contribute to this enhancement is needed. In this study, it was found that PB1 from an avian-origin influenza A virus [A/Cambodia/P0322095/2005, H5N1 (Cam)] could enhance the polymerase activity of an attenuated human isolated virus, A/WSN/33, carrying the PB2 K627E mutation (WSN627E) in vitro. Furthermore, 473V and 598P in the Cam PB1 were identified as the residues responsible for this enhanced activity. The results from recombinant virus experiments demonstrated the contribution of PB1 amino acids 473V and 598P to polymerase activity in mammalian cells and in mice. Interestingly, 473V is conserved in pH1N1 viruses from the 2009 pandemic. Substitution of 473V by leucine in pH1N1 PB1 led to a decreased viral polymerase activity and a lower growth rate in mammalian cells, suggesting that the PB1 473V also plays a role in maintaining efficient virus replication of the pH1N1 virus. Thus, it was concluded that two amino acids in avian-origin PB1, 473V and 598P, contribute to the polymerase activity of the H5N1 virus, especially in mammalian cells, and that 473V in PB1 also contributes to efficient replication of the pH1N1 strain.
authors.affiliation: Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, PR China.
authors.forename: Chen
authors.initials: C
authors.lastname: Xu
authors.affiliation: Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, PR China.
authors.forename: Wei-Bin
authors.initials: WB
authors.lastname: Hu
authors.affiliation: Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, PR China.
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.affiliation: Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, PR China.
authors.forename: Yun-Xia
authors.initials: YX
authors.lastname: He
authors.affiliation: Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, PR China.
authors.forename: Tong-Yan
authors.initials: TY
authors.lastname: Wang
authors.affiliation: Shanghai Institute of Biological Products, Shanghai 200052, PR China.
authors.forename: Ze
authors.initials: Z
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, Hubei, PR China.
authors.forename: Tian-Xian
authors.initials: TX
authors.lastname: Li
authors.affiliation: College of Veterinary Medicine, China Agricultural University, Beijing 100094, PR China.
authors.forename: Jin-Hua
authors.initials: JH
authors.lastname: Liu
authors.affiliation: Institut Pasteur in Cambodia, 5 Monivong Blvd, PO Box 983, Phnom Penh, Cambodia.
authors.forename: Philippe
authors.initials: P
authors.lastname: Buchy
authors.affiliation: Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, PR China.|Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Sun
mesh_terms: D019943:Amino Acid Substitution; D000596:Amino Acids / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D004252:DNA Mutational Analysis; D005260:Female; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000472:pathogenicity*; D051379:Mice; D008807:Mice, Inbred BALB C; D011995:Recombination, Genetic; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D000596:Amino Acids; D014764:Viral Proteins; C077346:influenza virus polymerase basic protein 1