Comparison of the three large polymerase proteins of influenza A, B, and C viruses.
The three large RNA segments of influenza C virus C/JJ/50 were cloned and sequenced, and the deduced amino acid sequences were compared with those of the polymerase (P) proteins of influenza A and B viruses. The coding strategy of the C virus RNA segments is the same as that for the large A and B virus segments as one long open reading frame is present in each segment. RNA segment 1 of influenza C virus encodes the equivalent of the PB2 protein; it has an approximate 25% sequence identity with the corresponding (cap binding) influenza A and B virus PB2 proteins. The PB1 protein of influenza C virus, coded for by segment 2, has an approximate 40% sequence identity with the corresponding proteins of influenza A and B viruses including the Asp-Asp sequence motif found in many RNA polymerase molecules. The PB1 polymerase is thus the most highly conserved protein among the influenza A, B, and C viruses. Although the protein coded for by RNA 3 of influenza C virus shows an approximate 25% sequence identity with the acid polymerase (PA) proteins of the A and B viruses, its sequence does not display any acid charge features at neutral pH. This protein is thus referred to as the P3 (rather than the PA) protein of influenza C virus.
Yamashita
M
M
Department of Microbiology, Mount Sinai School of Medicine, New York, New York 10029.
Krystal
M
M
Palese
P
P
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D005814:Genes, Viral; D009980:Influenza A virus / Q000201:enzymology* / Q000235:genetics; D009981:Influenza B virus / Q000201:enzymology* / Q000235:genetics; D009982:Gammainfluenzavirus / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009975:Orthomyxoviridae / Q000201:enzymology*; D012367:RNA, Viral / Q000235:genetics*
D012367:RNA, Viral; D012321:DNA-Directed RNA Polymerases