Dr1, a TATA-binding protein-associated phosphoprotein and inhibitor of class II gene transcription

We have discovered a protein termed Dr1 that interacts with the TATA-binding protein, TBP. The association of Dr1 with TBP results in repression of both basal and activated levels of transcription. The interaction of Dr1 with TBP precludes the formation of a transcription-competent complex by inhibiting the association of TFIIA and/or TFIIB with TBP. Dr1 activity is associated with a 19 kd protein. A cDNA clone encoding Dr1 was isolated. Dr1 is phosphorylated in vivo and phosphorylation of Dr1 affected its interaction with TBP. Our results suggest a regulatory role for Dr1 in repression of transcription mediated via phosphorylation.