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The EMBO Journal
(1997) 16, 1248–1257, doi:10.1093/emboj/16.6.1248
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| Roles of the influenza virus polymerase and nucleoprotein in forming a functional RNP structure |
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Klaus Klumpp, Rob W.H. Ruigrok and Florence Baudin
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EMBL Grenoble Outstation, c/o ILL, BP 156, 38042 Grenoble Cedex 9, France
Received 8 September 1996; Revised 13 November 1996.
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| Abstract |
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| Influenza virus transcription and replication is performed by ribonucleoprotein particles (RNPs). They consist of an RNA molecule covered with many copies of nucleoprotein (NP) and carry a trimeric RNA polymerase complex. RNA modification analysis and electron microscopy performed on native RNPs suggest that the polymerase forms a complex with both conserved viral RNA (vRNA) ends, whereas NP binding exposes the RNA bases to the solvent. After chemical removal of the polymerase, the bases at the vRNA extremities become reactive to modification and the vRNPs behave as structures with free ends, as judged from the observation of salt-induced conformational changes by electron microscopy. The vRNA appears to be completely single-stranded in polymerase-free RNPs despite a partial, inverted complementarity of the vRNA ends. The absence of a stable double-stranded panhandle structure in polymerase-free RNPs has important implications for the mechanism of viral transcription and the switch from transcription to replication. |
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| Keywords: influenza A virus, RNA conformation, RNA polymerase, viral transcription |
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