Yeast and human TFIID with altered DNA-binding specificity for TATA elements.

TFIID is the highly conserved, but species-specific, component of the RNA polymerase II transcription machinery that binds specifically to the TATA element (consensus TATAAA). Using a genetic selection, we isolated an altered specificity derivative of yeast TFIID that permits transcription from promoters containing a mutated TATA element (TGTAAA). Biochemical analysis indicates that this TFIID derivative has specifically gained the ability to bind TGTAAA efficiently. The mutant protein contains three substitutions within a 12 amino acid region; two of these are necessary and primarily responsible for the altered specificity. An analogous version of human TFIID, generated by introducing the same amino acid substitutions in the corresponding region of the protein, can support basal and GCN4-activated transcription in yeast cells from a TGTAAA-containing promoter. These results define a surface of TFIID that directly interacts with the TATA element, and they indicate that human TFIID can respond to acidic activator proteins in conjunction with the other components of the yeast transcription machinery.