Patent ID: 7892793

Claim:
A method of enhancing the ability of a shRNA to mediate RNA interference (RNAi) comprising (i) providing a shRNA comprising a duplex stem comprising an antisense stem portion having a length of 21 nucleotides and a sense stem portion, wherein said shRNA is targeted to a gain-of-function mutant allele, and (ii) enhancing the asymmetry of said stem, such that the ability of the shRNA to mediate RNAi is enhanced, wherein the asymmetry is enhanced by lessening the base pair strength between base pairs at the 5′ end of the antisense strand stem portion and corresponding base pairs in the 3′ end of the sense stem portion, wherein the base pair strength is less due to introduction of a single mismatched base pair between the 5′ end of the antisense stem portion and the 3′ end of the sense stem portion at position 3 from the 5′ end of the antisense strand portion.