293FT cells were seeded in 24-well plates and were transfected 16 h later with 400 ng of a shRNA expression vector, 40 ng of pGL3-IFNA1 or pGL3-IFNB, 20 ng of pRL-TK and 50 ng of pCR3.1-IRF-7A. Cells were collected 48 h after transfection. Luciferase assays were performed with the Dual-Glo Õ Luciferase Assay system reagents (Promega, Madison, WI) and luminescence quantified with a Modulus Microplate reader (Turner BioSystems, Sunnyvale, CA, USA). Ratios of firefly luciferase (from the pGL3 vectors) to Renilla luciferase (from the pRL-TK vector) were calculated, and that of the sh-B971 sample was normalized to 100%.