Figure 1.

Tip activates SRF independent of MAPK. Jurkat T cells were transiently transfected with expression plasmids coding for the viral oncoprotein Tip of HVS-C488. Empty vector served as a negative control. For inhibition of MAPK signaling, cells were left untreated or treated with U0126 (25 μM), PD0325901 (1 μM) or solvent (DMSO) for 40 h. As positive controls, vector-transfected cell were stimulated with PMA (20 ng/ml) in the absence or presence of the MEK inhibitors for 15 h. (A) Activity of cotransfected pSRE-Luc displayed as mean values and standard deviations of an assay performed in triplicates, which is representative for three independent experiments. Statistical significance for correlated samples, p < 0.05 (*); p > 0.05 (ns). (B) Activity of cotransfected p3D.A-Luc summarized from six independent experiments. Statistical significance for independent samples, p < 0.001 (***); p > 0.05 (ns). (C) Verification of MEK inhibition by detection of ERK1/2 phosphorylation and expression as well as control of Tip expression by immunoblot analyses with whole cell lysates obtained 48 h post transfection