Molecular dissection of influenza virus RNA polymerase: PB1 subunit alone is able to catalyze RNA synthesis.
Influenza virus RNA polymerase with the subunit structure PB1-PB2-PA is involved in both transcription and replication of the RNA genome. Enzyme reconstitution experiments indicated that all three P proteins are required for RNA synthesis in vitro (Kobayashi, et al. Virus Res 22, 235-245, 1992). Nuclear extracts of HeLa cells infected with three kinds of the recombinant vaccinia virus, each carrying one of the three P protein cDNAs, exhibited the activity of complete replication, that is, vRNA-sense RNA-directed and cRNA-sense RNA-directed RNA synthesis in the absence of primers. The nuclear extract from cells singly infected with the virus carrying PB1 cDNA exhibited a significant level of model v-sense RNA-directed RNA synthesis activity. Thus we conclude that PB1 is the catalytic subunit of influenza virus RNA polymerase and that under certain conditions, PB1 alone is able to catalyze RNA synthesis in vitro.
Toyoda
T
T
Department of Molecular Genetics, National Institute of Genetics, Shizuoka, Japan.
Kobayashi
M
M
Nakada
S
S
Ishihama
A
A
D001483:Base Sequence; D015870:Gene Expression; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D009980:Influenza A virus / Q000201:enzymology*; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000096:biosynthesis*; D012324:RNA-Dependent RNA Polymerase; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D006163:Ribonuclease T1 / Q000378:metabolism; D012259:Ribonuclease, Pancreatic / Q000378:metabolism; D014616:Vaccinia virus / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
C057027:PB2 protein, Influenzavirus A; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; C077346:influenza virus polymerase basic protein 1; D012324:RNA-Dependent RNA Polymerase; D006163:Ribonuclease T1; D012259:Ribonuclease, Pancreatic