RNA polymerase of influenza virus: role of NP in RNA chain elongation.
Ribonucleoprotein (RNP) cores of influenza virus A/PR/8/34 were dissociated into RNA polymerase (PB1-PB2-PA complex)-associated genome RNA and nuclear protein (NP) fractions by CsCl centrifugation. The RNA polymerase-RNA complexes were capable of catalyzing the endonucleolytic cleavage of capped RNA, the initiation of primer-dependent RNA synthesis, and the synthesis of small-sized RNA, but were unable to synthesize template-sized RNA. By adding the NP protein to the RNA polymerase-RNA complexes, RNP (RNA polymerase-RNA-NP) complexes were reconstituted; they synthesized template-sized transcripts as did native RNP cores. These observations are consistent with the model where viral RNA polymerase is composed of the three P proteins while NP is essential for the elongation of RNA chains. RNP was completely dissociated into RNA-free proteins (PB1, PB2, PA, and NP) and a protein-free genome RNA fraction by centrifugation in cesium trifluoroacetate (CsTFA) and glycerol. By mixing the protein and RNA fractions, primer-dependent RNA-synthesizing activity was regained. These complexes, however, produced only small-sized RNA, presumably due to incorrect assembly of NP on viral RNA.
Honda
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Department of Molecular Genetics, National Institute of Genetics, Shizuoka.
Uéda
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Nagata
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Ishihama
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D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D009980:Influenza A virus / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D012367:RNA, Viral / Q000096:biosynthesis*; D012261:Ribonucleoproteins / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism
D009687:Nuclear Proteins; D012367:RNA, Viral; D012261:Ribonucleoproteins; D014764:Viral Proteins; D012321:DNA-Directed RNA Polymerases