MOLECULAR-CLONING AND EXPRESSION OF THE 32-KDA SUBUNIT OF HUMAN TFIIDREVEALS INTERACTIONS WITH VP16 AND TFIIB THAT MEDIATE TRANSCRIPTIONALACTIVATION

Transcription factor TFIID consists of TATA binding protein (TBP) and at least eight TBP-associated factors (TAFs), As TAFs are required for activated but not basal transcription, we have proposed that TAFs act as coactivators to mediate signals between activators and the basal t ranscription machinery, Here we report the cloning, expression, and bi ochemical characterization of the 32-kDa subunit of human (h) TFIID, t ermed hTAF(II)32, We find that hTAF(II)32 is the human homologue of Dr osophila TAF(II)40. In vitro protein-protein interaction assays reveal that as observed with Drosophila TAF(II)40, hTAF(II)32 interacts with the C-terminal 39-amino acid activation domain of the acidic transact ivator viral protein 16 (VP16) as well as with the general transcripti on factor TFIIB, Moreover, a partial recombinant TFIID complex contain ing hTAF(II)32 was capable of mediating in vitro transcriptional activ ation by the VP16 activation domain, These findings indicate that spec ific activator-coactivator interactions have been conserved between hu man and Drosophila and provide additional support for the function of these interactions in mediating transcriptional activation.