Patent ID: 8318921

Claim:
A method of silencing a target gene, comprising: providing an initiator to a cell, wherein the cell comprises a detection target and a silencing target gene, wherein the detection target is different from the silencing target gene, wherein the initiator comprises a) a detection target binding region that binds to the detection target and b) an initiator region that is initially sequestered and becomes available for binding when the detection target binds to the detection target binding region; providing a first substrate monomer to the cell, wherein the first substrate monomer comprises a silencing target complement region that is substantially complementary to a portion of the silencing target gene, and an initiator complement region, wherein the initiator complement region hybridizes to the initiator region after it becomes available for binding; and providing a second substrate monomer to the cell, wherein the second substrate monomer comprises a silencing target region that is substantially complementary to the silencing target complement region, wherein the silencing target complement region hybridizes to the silencing target region to form a RNA duplex molecule that can be processed by Dicer, and wherein Dicer processes the RNA duplex molecule to form a small interfering RNA that silences the silencing target gene.