Figure 5.

NF-κB/NFAT binding sites in the viral LTR are required for Cul3 to reduce HIV-1 mRNA expression. (a) Schematic representation of the HIV-1 LTR promotor region with various transcription factor binding sites. (b) HEK293T cells were transiently transfected with two independent siRNAs targeting Cul3 (CUL3_5 and CUL3_9) or a non-targeting siRNA as control. 48 h after transfection, cells were infected with a wild type VSVg-pseudotyped HIV-1 NL4-3 luciferase reporter virus (WT) or mutants thereof, in which the binding sites of various transcription factors within the viral LTR have been abrogated (∆STAT5 I, II, III; ∆NF-IL6 I, II; ∆USF and ∆NF-κB/NFAT I, II). 24 h post infection, viral mRNA expression was analyzed by qRT-PCR. Data is plotted as fold-enhancement compared to non-targeting control siRNA (n = 2–3 +/− SD). ** p < 0.01; n.s.: not significant.