For shRNA, lentivirus was produced by combining MISSION constructs for packaging (psPAX2), envelope (pDM2G) and targeting shRNA or a non-targeting vector (pLKO.1), at a 4:2:1 ratio (Sigma Aldrich, St. Louis, MO). Polyethylenimine (PEI; Polysciences) was combined with DNA at a 3:1 ratio, and added to 70% confluent HEK 293LTV cells. Conditioned media was collected 24 and 48 hrs post transfection by centrifugation, and viral supernatant added to cells with 8 μg/ml hexadimethrine bromide (polybrene, Sigma-Aldrich). Gene expression was measured by QPCR 24 hrs following puromycin selection (2 μg/ml).