FIG. 7.

SMRT and TFIIB interact functionally. (A) SMRT expression inhibits transcriptional activation by TFIIB. A GAL4-DBD or GAL4-DBD–TFIIB construct (125 ng per plate) was introduced into CV-1 cells alone or with increasing amounts of a pSG5-SMRT derivative (1× = 125 ng/plate). The activity of the cointroduced GAL4 17-mer-luciferase (LUC) reporter was determined relative to that of the pCH110 lacZ internal control as for Fig. 2 and 3. (B) TFIIB expression counteracts SMRT-mediated repression. A GAL4-DBD or GAL4-DBD–SMRT fusion construct (125 ng per plate) was expressed in CV-1 cells alone or together with TFIIB (1× = 125 ng/plate). The activity of the cointroduced GAL4 (17-mer)-luciferase reporter was then determined relative to that of the pCH110 lacZ internal control as for Fig. 2 and 3.