title: In vivo activity and duration of short interfering RNAs containing a synthetic 5'-phosphate.
abstract: Endogenous and exogenous short interfering RNAs (siRNAs) require a 5'-phosphate for loading into Ago2 and cleavage of the target mRNA. We applied a synthetic 5'-phosphate to siRNA guide strands to evaluate if phosphorylation in vivo is rate limiting for maximal siRNA knockdown and duration. We report, for the first time, an in vivo evaluation of siRNAs with a synthetic 5'-phosphate compared to their unphosphorylated versions. siRNAs that contained a 5'-phosphate had the same activity in vivo compared with unphosphorylated siRNAs, indicating phosphorylation of an siRNA is not a rate limiting step in vivo.
authors.affiliation: Sirna Therapeutics, San Francisco, California, USA. denise.kenski@healthinteractions.com
authors.forename: Denise M
authors.initials: DM
authors.lastname: Kenski
authors.forename: Aarron T
authors.initials: AT
authors.lastname: Willingham
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Haringsma
authors.forename: Jenny J
authors.initials: JJ
authors.lastname: Li
authors.forename: W Michael
authors.initials: WM
authors.lastname: Flanagan
mesh_terms: D000818:Animals; D001055:Apolipoproteins B / Q000096:biosynthesis / Q000235:genetics; D001483:Base Sequence; D002460:Cell Line; D017930:Genes, Reporter; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010710:Phosphates / Q000737:chemistry*; D011393:Procollagen-Proline Dioxygenase / Q000096:biosynthesis / Q000235:genetics; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000737:chemistry* / Q000235:genetics*
chemical_list: D001055:Apolipoproteins B; D010710:Phosphates; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D008156:Luciferases; D011393:Procollagen-Proline Dioxygenase; C490189:Egln1 protein, mouse; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases