title: Hairpin loop structure in the 3' arm of the influenza A virus virion RNA promoter is required for endonuclease activity.
abstract: Previous studies have shown that the 5' arm of the influenza A virus virion RNA promoter requires a hairpin loop structure for efficient endonuclease activity of influenza virus RNA polymerase, an activity that is required for the cap-snatching activity of primers from host pre-mRNA. Here we examine whether a hairpin loop is also required in the 3' arm of the viral RNA promoter. We study point mutations at each nucleotide position (1 to 12) within the 3' arm of the promoter as well as complementary "rescue" mutations which restored base pairing in the stem of a potential hairpin loop. Our results suggest that endonuclease activity is absolutely dependent on the presence of a 3' hairpin loop structure. This is the first direct evidence for RNA secondary structure within the 3' arm being required for a specific stage, i.e., endonuclease cleavage, in the influenza virus replicative cycle.
authors: Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom.
authors: M B
authors: MB
authors: Leahy
authors: H C
authors: HC
authors: Dobbyn
authors: G G
authors: GG
authors: Brownlee
mesh_terms: D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D009980:Influenza A virus / Q000201:enzymology* / Q000235:genetics; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D012367:RNA, Viral / Q000737:chemistry*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014771:Virion
chemical_list: C061290:PA protein, influenza viruses; C057027:PB2 protein, Influenzavirus A; D012367:RNA, Viral; D014764:Viral Proteins; C077346:influenza virus polymerase basic protein 1; D012324:RNA-Dependent RNA Polymerase; D012321:DNA-Directed RNA Polymerases