NS1 mRNA M2 mRNA M1 mRNA NS2 mRNA Viral mRNA Splicing (M, NS segments) Authored: Bortz, E, Garcia-Sastre, A, 2007-02-12 19:39:05 Pubmed10920397 Pubmed11421366 Pubmed1710647 Pubmed1824958 Pubmed6246509 Pubmed6945577 Pubmed7541537 Pubmed8895585 Reactome Database ID Release 43192781 Reactome, http://www.reactome.org ReactomeREACT_9402 Reviewed: Squires, B, 2007-02-12 19:39:22 The viral polymerase complex produces positive-sense viral mRNA with host-cell derived 5' methyl caps. Alternately spliced mRNA transcribed from M and NS vRNA segments 7 and 8, producing the spliced mRNA for M2 and NEP/NS2, respectively, are thought to be coupled to the cellular splicing and export mechanisms (Lamb, 1980; Lamb, 1981; Chen, 2000; Li, 2001). As segments 7 and 8 each encode two proteins, splicing must be regulated allowing for alternative mRNAs, with the spliced products in the minority (approximately 10%). M1 splicing may be regulated by the viral polymerase and the cellular SR splicing protein SF2/ASF (Shih, 1995; Shih, 1996); while NS1 splicing appears to be regulated by the viral mRNA intrinsically (Alonso-Caplen, 1991; Valcarel, 1991).