FIG 1 .

Lentivirus-based shRNA screen for ISGs that affect WNV infection. (A) Schematic of pGIPZ lentivirus vector expressing shRNA and GFP. LTR, long terminal repeat of HIV; CMV, immediate early promoter from human cytomegalovirus; IRES, internal ribosome entry site; Puro, puromycin selection marker. (B) Cartoon of the shRNA screen. Packaged and pseudotyped lentiviruses expressing 813 shRNAs were transduced into HeLa cells (list in Table S1 in the supplemental material). Forty-eight hours later, cells were treated with human IFN-β (10 IU/ml for 6 h) and then infected with WNV at an MOI of 5. Forty-eight hours later, cells were processed by flow cytometry. (C) Representative flow cytometry contour plots (from two independent screens) showing cells transduced with lentiviral vectors containing a scrambled shRNA control or shRNA specific against ISGs with top Z scores from the primary screen. The x axis reports the lentivirus transduction efficiency as represented by GFP expression, and the y axis shows infectivity of WNV, as judged by anti-envelope protein staining.