Fig. 4.
A dominant-negative DNA-binding mutant of p53 counters the repression of Stathmin by HTLV-1 p30II. (A) 293 HEK cells were cotransfected with 0.25 mg of pEGFP-N3-HTLV-1 p30II-GFP in combination with increasing amounts (0.25 and 0.5 mg) of pCEP4 expression constructs for wildtype p53 or a dominant-negative DNA-binding mutant, p53-R175H (Hermeking et al., 1997), or a CβS empty vector control. The relative expression of Stathmin, p53, and HTLV-1 p30II-GFP was detected by SDS-PAGE and immunoblotting. The Actin protein levels are shown for comparison. (B) The relative expression of Stathmin and Actin in A was quantified by densitometry analysis. (C) 293 cells were cotransfected with 0.25 mg of an ESelectin promoter-luciferase reporter plasmid and various expression constructs for HTLV-1 Tax, p30II-GFP, or the dominant-negative p53-R175H mutant, or CβS empty vector. Relative luciferase activities were measured and normalized for equivalent total cellular protein levels. UT, untransfected cells. All the data are representative of at least three independent experiments. The data in B and C represent the experimental mean ± standard deviation (error bars).