Abstract
Protein acetylation has emerged as a means of controlling levels of mRNA synthesis in eukaryotic cells. Here we report that acetyl coenzyme A (acetyl-CoA) stimulates RNA polymerase II transcription in vitro in the absence of histones. The effect of acetyl-CoA on basal and activated transcription was studied in a human RNA polymerase II transcription system reconstituted from recombinant and highly purified transcription factors. Both basal and activated transcription were stimulated by the addition of acetyl-CoA to transcription reaction mixtures. By varying the concentrations of general transcription factors in the reaction mixtures, we found that acetyl-CoA decreased the concentration of TFIID required to observe transcription. Electrophoretic mobility shift assays and DNase I footprinting revealed that acetyl-CoA increased the affinity of the general transcription factor TFIID for promoter DNA in a TBP-associated factor (TAF)-dependent manner. Interestingly, acetyl-CoA also caused a conformational change in the TFIID-TFIIA-promoter complex as assessed by DNase I footprinting. These results show that acetyl-CoA alters the DNA binding activity of TFIID and indicate that this biologically important cofactor functions at multiple levels to control gene expression.
ACKNOWLEDGMENTS
We thank P. Beaurang, K. Goodrich, D. King, N. Tanese, R. Tjian, and E. Wang for contributing to the development of methods for immunopurifying functional TFIID and M. Maxon for providing TFIIE. We are grateful to N. Ahn and S. C. Galasinski for helpful discussions and for comments on the manuscript and to T. R. Cech, L. J. Kim, J. F. Kugel, I. M. Ota, and A. Pardi for comments on the manuscript.
This research was supported by Public Health Service grant GM-55235 from the National Institutes of Health, an American Cancer Society Institutional Research Grant to the University of Colorado Cancer Center, a University of Colorado Junior Faculty Development Award, and a Leukemia Society of America Special Fellowship to J.A.G.