Influence of assembly of siRNA elements into RNA-induced silencing complex by fork-siRNA duplex carrying nucleotide mismatches at the 3'- or 5'-end of the sense-stranded siRNA element.


Publication Type:

Source:

Biochem Biophys Res Commun, Volume 329, Issue 2, p.516-21 (2005)

Keywords:

3' Flanking Region, 5' Flanking Region, Base Pair Mismatch, Base Sequence, Gene Expression Regulation, Gene Silencing, HeLa Cells, Humans, Luciferases, Molecular Sequence Data, RNA, RNA Interference, RNA, Small Interfering, Structure-Activity Relationship

Abstract:

<p>RNA interference (RNAi) is a powerful method for suppressing the expression of a gene of interest, and can be induced by 21-25 nucleotide small interfering RNA (siRNA) duplexes homologous to the silenced gene, which function as sequence-specific RNAi mediators in RNA-induced silencing complexes (RISCs). In the previous study, it was shown that fork-siRNA duplexes, whose sense-stranded siRNA elements carried a few nucleotide mismatches at the 3'-ends against the antisense-stranded siRNA elements, could enhance RNAi activity more than conventional siRNA duplexes in cultured mammalian cells. In this study, we further characterized fork-siRNA duplexes using reporter plasmids carrying target sequences complementary to the sense- or antisense-stranded siRNA elements in the untranslated region of Renilla luciferase. The data presented here suggest that nucleotide mismatches at either the 3'- or 5'-end of the sense-stranded siRNA elements in fork-siRNA duplexes could influence assembly of not only the antisense-stranded siRNA elements but also the sense-stranded elements into RISCs. In addition, we further suggest the possibility that there could be a positional effect of siRNA duplex on RNAi activity.</p>