Patent ID: 8796016

Claim:
A method for reducing the level of a target mRNA in a cell in vitro, comprising contacting a cell with an isolated synthetically prepared, double-stranded RNA molecule which mediates a reduction in the level of a target mRNA, wherein said molecule consists of two separate RNA strands each independently consisting of 19-23 nucleotides, wherein said separate RNA strands form a single continuous double-stranded region and wherein at least one strand of said RNA molecule has a 3′-overhang from 1-5 nucleotides, wherein one of said strands is complementary to a portion of a target mRNA, and said RNA molecule comprises at least one stabilizing modification at the 5′ end or the 3′ end, or both ends, of the double-stranded RNA molecule, wherein said stabilizing modification is selected from the group consisting of a sugar modified ribonucleotide and a backbone-modified ribonucleotide containing a phosphorothioate group, wherein said sugar modified ribonucleotide 2′-OH group is replaced by a member selected from the group consisting of H, OR, R, halo, SH, SR, NH 2 , NHR, NR 2 and CN, wherein R is C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, and halo is F, C 1 , Br or I.