title: Influenza A viruses with different amino acid residues at PB2-627 display distinct replication properties in vitro and in vivo: revealing the sequence plasticity of PB2-627 position.
abstract: Sequence analyses of influenza PB2 sequences indicate that the 627 position almost exclusively contains either lysine (K) or glutamic acid (E), suggesting a high sequence constraint at this genetic marker. Here, we used a site-directed random mutagenesis method to demonstrate that PB2-627 position has a high sequence plasticity. Recombinant viruses carrying various amino acid residues at this position are viable in cell cultures. These PB2-627 mutants showed various polymerase activities and replication kinetics in mammalian and avian cells as well as pathogenicity in mice. Serially passaging these mutants in MDCK cells generated some compensatory PB2 mutations that can restore polymerase activities of the PB2-627 mutants. Of these, PB2-D309N was identified as a novel one. Besides showing that influenza virus can tolerate a wide range of amino acid residues at the PB2-627 position, this study also demonstrates a potential strategy to identify novel mutations that can enhance viral polymerase.
authors.affiliation: Centre of Influenza Research & School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Alex W H
authors.initials: AWH
authors.lastname: Chin
authors.affiliation: Centre of Influenza Research & School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Olive T W
authors.initials: OTW
authors.lastname: Li
authors.affiliation: Centre of Influenza Research & School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong; The HKU-Pasteur Research Pole & School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Chris K P
authors.initials: CKP
authors.lastname: Mok
authors.affiliation: Centre of Influenza Research & School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Miko K W
authors.initials: MKW
authors.lastname: Ng
authors.affiliation: Centre of Influenza Research & School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong; The HKU-Pasteur Research Pole & School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Malik
authors.initials: M
authors.lastname: Peiris
authors.affiliation: Centre of Influenza Research & School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong. Electronic address: llmpoon@hku.hk.
authors.forename: Leo L M
authors.initials: LLM
authors.lastname: Poon
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D005260:Female; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D006801:Humans; D009980:Influenza A virus / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D009976:Orthomyxoviridae Infections / Q000821:virology; D012367:RNA, Viral; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: C502893:PB2 protein, influenza virus; D012367:RNA, Viral; D014764:Viral Proteins
keywords: Influenza; PB2; PB2-627; Polymerase; Random mutagenesis