Figure 1. NF2 suppresses T-antigen protein expression and T-antigen mediated activation of JCV_E and JCV_L promoters.

U-87 MG glioblastoma cells were transiently transfected with luciferase reporter constructs encoding either the JCV_E (a, c) or JCV_L (b, d) promoters, and plasmids encoding JCV T-antigen or HA tagged NF2 (HA-NF2). Immunoblotting of protein lysates revealed a dose-dependent decline in the expression of T-antigen, in the presence of increasing amounts of HA-NF2 (a, b lanes 5–8). Extracts were also used to conduct luciferase assays to determine JCV_E (c) or JCV_L (d) activation in response to these various transfection conditions. Results are shown here as fold change in luciferase activity, relative to the activity of the promoter alone. NF2 does not appreciably affect the activities of either promoter, while T-antigen greatly enhances the activity of both promoters. In combination, NF2 does prevent T-antigen from enhancing the activities of JCV_E and JCV_L.