Patent ID: 8114851

Claim:
A method for inhibiting expression of a target gene in a mammalian cell in vitro, comprising: a) introducing into said mammalian cell in vitro an isolated double stranded RNA (dsRNA) consisting of two separate oligoribonucleotide single strands that are chemically linked by a disulfide bridge, wherein one strand of said dsRNA is complementary to an RNA transcript of at least part of said target gene and the other strand of the dsRNA is complementary to the first strand, and wherein the dsRNA is 21 base pairs in length; and b) maintaining the cell produced in step a) for a time sufficient to obtain degradation of an RNA transcript of said target gene, wherein said dsRNA, when introduced into the presence of said RNA transcript, reduces an amount of said RNA transcript via dsRNA-mediated interference, thereby inhibiting the expression of said target gene in said cell in vitro.