title: Two mutations in the C-terminal domain of influenza virus RNA polymerase PB2 enhance transcription by enhancing cap-1 RNA binding activity.
abstract: Influenza virus RNA polymerase (RdRp) PB2 is the cap-1 binding subunit and determines host range and pathogenicity. The mutant human influenza virus RdRp containing PB2 D701N and D701N/S714R demonstrated enhanced replicon activity in mammalian cells. We investigated the influence of these mutations on RdRp activity. Cap-1-dependent transcription activities of D701N/S714R, D701N, and S714R were 348.1±6.2%, 146.4±11%, and 250.1±0.8% of that of the wild type (wt), respectively. Replication activity of these mutants for complimentary RNA to viral RNA ranged from 44% to 53% of that of the wt. Cap-1 RNA-binding activities of D701N/S714R, D701N, and S714R were 262±25%, 257±34%, and 315±9.6% of that of the wt, respectively, and their cap-dependent endonuclease activities were similar to that of the wt. These mutations did not affect template RNA-binding activities. D701N and S714R mutations enhanced transcription by enhancing cap-1 RNA-binding activity, but they may exhibit decreased efficiency of priming by the cap-1 primer. These mutations at the C-terminal domain of PB2 may affect its cap-binding domain.
authors.affiliation: Unit of Viral Genome Regulation, Institut Pasteur of Shanghai, Chinese Academy of Sciences, 411 Hefei Road, 200025 Shanghai, PR China.
authors.forename: Shijian
authors.initials: S
authors.lastname: Zhang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.forename: Jinlan
authors.initials: J
authors.lastname: Wang
authors.forename: Kiyohisa
authors.initials: K
authors.lastname: Mizumoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Toyoda
mesh_terms: D015967:Gene Expression Regulation, Viral; D057809:HEK293 Cells; D006801:Humans; D009980:Influenza A virus / Q000201:enzymology* / Q000472:pathogenicity; D007251:Influenza, Human / Q000201:enzymology / Q000821:virology*; D009154:Mutation; D009713:Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D039381:RNA Cap-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D012315:RNA Caps / Q000235:genetics*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism; D000098556:mRNA Guanylyltransferases
chemical_list: C057027:PB2 protein, Influenzavirus A; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps; D014764:Viral Proteins; D009713:Nucleotidyltransferases; D012324:RNA-Dependent RNA Polymerase; D000098556:mRNA Guanylyltransferases