Patent ID: 8202846

Claim:
A method for attenuating expression of a target gene in a mammalian cell, the method comprising: introducing into a mammalian cell an expression vector comprising: (i) an RNA polymerase promoter, and (ii) a sequence encoding a short hairpin RNA molecule comprising a double-stranded region, wherein the double-stranded region consists of at least 20 nucleotides but not more than 29 nucleotides, wherein the short hairpin RNA molecule is a substrate for Dicer-dependent cleavage and does not trigger a protein kinase RNA-activated (PK) response in the mammalian cell, wherein the double-stranded region of the short hairpin RNA molecule comprises a sequence that is complementary to a portion of the target gene, and wherein the short hairpin RNA molecule is stably expressed in the mammalian cell in an amount sufficient to attenuate expression of the target gene in a sequence specific manner, and is expressed in the cell without use of a PK inhibitor, whereby expression of the target gene is inhibited.