HUMAN TAF(II)30 IS PRESENT IN A DISTINCT TFIID COMPLEX AND IS REQUIRED FOR TRANSCRIPTIONAL ACTIVATION BY THE ESTROGEN-RECEPTOR

We showed previously that coactivators mediating stimulation by different activators were associated with the TATA-binding protein (TBP) in distinct TFIID complexes. We have characterized a human TBP-associated factor (TAF), hTAF(II)30, associated with a subset of TFIID complexes. hTAF(II)30 interacts with the AF-2-containing region E of the human estrogen receptor (ER), but not with ER AF-1 or VP16. An antibody against hTAF(II)30 inhibited transcriptional stimulation by the ER AF-2 without affecting basal or VP16-activated transcription and allowed the separation of TFIID complex(es) containing hTAF(II)30 from complexes mediating the activity of VP16. These results directly demonstrate the existence of functionally dis tinct TFIID populations that share common TAF(II)s but differ in specific TAF(II)s.