Patent ID: 8030473

Claim:
An siRNA-triggering or RNAi-triggering nucleic acid cassette, comprising: an initiator sequence that consists of about 20 to 25 nucleotides and has an initiation cleavage site between the tenth and eleventh or eleventh and twelfth nucleotides counted from the 3′ end of the initiator sequence, and wherein the initiator sequence is recognized by a RNA-induced Silencing Complex guided by an siRNA or a miRNA that has sufficient complementarity to said initiator sequence to initiate cleavage in 21-nucleotide register from said initiation cleavage site; and at least one 21-nucleotide gene suppressing segment engineered to be in about 21-nucleotide register counted either upstream or downstream from the initiation cleavage site, wherein the gene suppressing segment or its complement is complementary to RNA transcribed from a target gene selected for siRNA inhibition.