Two mutations in the C-terminal domain of influenza virus RNA polymerase PB2 enhance transcription by enhancing cap-1 RNA binding activity

Biochim Biophys Acta. 2012 Jan;1819(1):78-83. doi: 10.1016/j.bbagrm.2011.11.006. Epub 2011 Nov 30.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gene Expression Regulation, Viral
  • HEK293 Cells
  • Humans
  • Influenza A virus / enzymology*
  • Influenza A virus / pathogenicity
  • Influenza, Human / enzymology
  • Influenza, Human / virology*
  • Mutation
  • Nucleotidyltransferases / genetics*
  • Nucleotidyltransferases / metabolism
  • Protein Structure, Tertiary
  • RNA Cap-Binding Proteins / genetics*
  • RNA Cap-Binding Proteins / metabolism
  • RNA Caps / genetics*
  • RNA-Dependent RNA Polymerase / genetics*
  • RNA-Dependent RNA Polymerase / metabolism
  • Transcription, Genetic
  • Viral Proteins / genetics*
  • Viral Proteins / metabolism


  • PB2 protein, Influenzavirus A
  • RNA Cap-Binding Proteins
  • RNA Caps
  • Viral Proteins
  • Nucleotidyltransferases
  • RNA-Dependent RNA Polymerase
  • mRNA guanylyltransferase