Gene activity in a eukaryotic cell is regulated by accessory factors to RNA polymerase II, which include the general transcription factor complex TFIID, composed of TBP and TBP-associated factors (TAFs). Three TAFs that contain histone fold motifs (yTAF17, yTAF60 and yTAF61) are critical for transcriptional regulation in the yeast Saccharomyces cerevisiae and are found in both TFIID and SAGA, a multicomponent histone acetyltransferase transcriptional coactivator. Although these three TAFs were proposed to assemble into a pseudooctamer complex, we find instead that yTAF17, yTAF60 and yTAF61 form a specific TAF octamer complex with a fourth TAF found in TFIID, yTAF48. We have reconstituted this complex in vitro and established that it is an octamer containing two copies each of the four components. Point mutations within the histone folds disrupt the octamer in vitro, and temperature-sensitive mutations in the histone folds can be specifically suppressed by overexpressing the other TAF octamer components in vivo. Our results indicate that the TAF octamer is similar both in stoichiometry and histone fold interactions to the histone octamer component of chromatin.
|Number of pages
|Nature Structural Biology
|Published - 2001
Bibliographical noteFunding Information:
We thank B. Schlansky and M. Song for technical assistance; C. Brown, J. Reese, B. Simpson and J. Workman for critical reading of the manuscript, and to the gene regulation community at Penn State for stimulating discussions. We are also grateful to T. Richmond, in whose laboratory preliminary studies for this project were initiated. This work was supported by NIH grants to M.F., S.B. and S.T. S.B. is a Leukemia and Lymphoma Society Scholar.
ASJC Scopus subject areas
- Structural Biology