title: Additional methylation at the N(2)-position of the cap of 26S Semliki Forest virus late mRNA and initiation of translation.
abstract: Cap analysis of the late 26S Semliki Forest viral mRNA reveals that almost 30% of the caps possess both a methyl group at the N(7)-position and one at the N(2)-position. We have compared the degree of methylation of the caps of polysomal and non-polysomal 26S mRNA in order to check whether this feature is responsible for its translation late in infection. It was found that extra methyl groups on the caps cause a lower rate of initiation. Polysomal 26S mRNA contained less m2,7G- and m2,2,7G-caps than free 26S. The cap analog m2,2,7Gp was slightly less inhibitory than m7Gp in an in vitro translation system.
mesh_terms: D008745:Methylation; D014176:Protein Biosynthesis / Q000187:drug effects; D012314:RNA Cap Analogs / Q000494:pharmacology; D012315:RNA Caps / Q000032:analysis / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D012672:Semliki forest virus / Q000235:genetics* / Q000378:metabolism
chemical_list: D012314:RNA Cap Analogs; D012315:RNA Caps; D012333:RNA, Messenger; D012367:RNA, Viral