Depiction of the pHippy dual siRNA expression vector and some of its possible uses. a, pHippy has convergent opposing Human H1 and U6 polymerase III promoters that drive expression of both strands of any template cloned in between the BsmB 1 cloning sites. pHippy also contains the Puc origin and the Zeocin-resistance gene for propagation and replication in bacteria. As depicted the H1 and U6 promoters were modified to contain a polymerase III termination signal (TTTTT) between the -5 to -1 position of the promoter, and BsmBl sites. BsmBl is a type II restriction enzyme, which cuts outside of its recognition sequence and will in the case of pHippy leaves 3' TTTT overhangs on both strands of the plasmid as depicted. 19 nt target siRNA can be cloned into pHippy as double stranded oligos by addition of AAAA to the 5' ends of the oligos as depicted b. b, Proposed uses for the pHippy siRNA vector system.
Kaykas and Moon BMC Cell Biology 2004 5:16 doi:10.1186/1471-2121-5-16