title: A double-stranded RNA unwinding activity introduces structural alterations by means of adenosine to inosine conversions in mammalian cells and Xenopus eggs.
abstract: Amphibian eggs and embryos as well as mammalian cells have been reported to contain an activity that unwinds double-stranded RNA. We have now found that adenosine residues have been modified in the RNA products of this unwinding activity. Although the modified RNA remains double-stranded, the modification causes the RNA to be susceptible to single-strand-specific RNase and to migrate as a retarded smear on a native polyacrylamide electrophoresis gel. The modification is specific for double-stranded RNA. At least 40% of the adenosine residues can be modified in vitro in a given random sequence RNA molecule. By using standard two-dimensional TLC and HPLC analyses, the modified base has been identified as inosine. Mismatched base-pairing between inosine and uridine appears to be responsible for the observed characteristics of the unwound RNA. The biological significance of this modifying activity and also of the modified double-stranded RNA is discussed.
authors.affiliation: Wistar Institute, Philadelphia, PA 19104.
authors.forename: R W
authors.initials: RW
authors.lastname: Wagner
authors.forename: J E
authors.initials: JE
authors.lastname: Smith
authors.forename: B S
authors.initials: BS
authors.lastname: Cooperman
authors.forename: K
authors.initials: K
authors.lastname: Nishikura
mesh_terms: D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D001482:Base Composition; D002460:Cell Line; D004247:DNA / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007288:Inosine / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D014982:Xenopus laevis
chemical_list: D007288:Inosine; D004247:DNA; D000241:Adenosine