FIG. 7.

Human NRSE silences the activity of the heterologous SV40 promoter. The wild-type and mutated NRSEs of the IB1 promoter, WTNRSE and MUTNRSE, respectively, were cloned as dimers upstream an SV40 promoter. Constructs were then transiently transfected into HeLa, NIH 3T3, Jurkat, and RAW cells. WTNRSE activity is markedly decreased in all these cells compared to the basal activity of SV40LUC. The mutation in NRSE partially restored the activity of the MUTNRSE promoter. Luciferase activities were normalized using pRLCMVrenilla. Each experiment was performed at least three times in triplicate. All values are expressed as percentages of the SV40LUC activity and are means ± standard errors of the means (triple asterisk, P < 0.001).