SEPARATION OF THE TRANSCRIPTIONAL COACTIVATOR AND ANTIREPRESSION FUNCTIONS OF TRANSCRIPTION FACTOR IIA

Human transcription factor IIA (TFIIA) is composed of three subunits ( alpha, beta, and gamma). TFIIA interacts with the TATA-box binding pro tein and can overcome repression of transcription, TFIIA was found to be necessary for VP16-mediated transcriptional activation through a co activator function. We have separated the coactivator and antirepressi on activities of TFIIA. A TFIIA lacking the cu subunit was isolated fr om HeLa cells. This ''mini-TFIIA'' interacts with the TATA-box binding protein and can overcome repression of transcription, but it Is defec tive in transcriptional coactivator function.