Purification of a Yeast TATA Box-Binding Protein that Exhibits Human Transcription Factor IID Activity

By a series of conventional chromatographic procedures we have purified from whole-cell extracts of Saccharomyces cerevisiae yeast transcription factor IID (TFIID), which functionally substitutes for human TFIID in a complementation assay comprised of the adenovirus type 2 major late promoter and HeLa cell-derived RNA polymerase II, transcription factors IIA, IIB, and IIE. Similar to its human counterpart, yeast TFIID also exhibited specific binding to the adenovirus type 2 major late promoter TATA element, as shown by both DNase I footprinting and gel mobility shift assays. NaDodSO4/PAGE analyses showed that a 27-kDa polypeptide coeluted with TFIID complementing activity through each chromatographic step. In agreement with this result and also suggesting that the native protein is a monomer, gel-filtration experiments indicated a molecular mass of 28 kDa for TFIID under nondenaturing conditions. That the 27-kDa polypeptide represented TFIID was further demonstrated by the ability of an HPLC-purified protein to bind specifically after renaturation to the adenovirus type 2 major late promoter TATA sequence.