Figure 3.

Coexpression of hTAF_II28 promotes transcriptional activation by GAL4-Tax. HeLa cells were cotransfected by the calcium phosphate coprecipitation method with the reporter construct pG4G3CAT (2 μg; ref. 7) without or with pSG4-Tax (20 ng; ref. 7). Expression vectors for hTAF_II28 (1 μg), hTAF_II55 (100 ng), hTAF_II100 (2 μg), hTAF_II135 (500 ng), and TBP (1 μg) were added to the DNA mix as indicated. The amounts of hTAF_II expression vectors used for transfection were adjusted to give similar quantities of each hTAF_II as evaluated by immunoblotting analysis of corresponding whole cell extracts (data not shown). Quantification of the CAT protein (expressed in picograms per milliliter of cellular extract) was carried out by ELISA. Each point of transfection was performed in duplicate. (Bar = mean values.)