Patent ID: 7732193

Claim:
A method of expressing an siRNA within a cell, the method comprising: transfecting a packaging cell line with a retroviral construct; recovering recombinant retrovirus from the packaging cell line; and infecting a target cell in vitro with the recombinant retrovirus, wherein the retroviral construct comprises the R and U5 sequences from a 5′ lentiviral long terminal repeat (LTR), a self-inactivating lentiviral 3′ LTR, an RNA Polymerase III promoter region and an RNA coding region encoding an siRNA operably linked to an RNA Polymerase III promoter region; wherein the RNA polymerase III promoter region and the RNA coding region are located between the 5′ LTR and the 3′ LTR; wherein the RNA coding region encodes a self-complementary RNA molecule having a sense region, an antisense region and a loop region; and wherein the sense region and the antisense region are each between about 15 and about 30 nucleotides in length.