Mediator protein mutations that selectively abolish activated transcription
- Lawrence C. Myers*,†,
- Claes M. Gustafsson†,‡,
- Kathleen C. Hayashibara§,
- Patrick O. Brown§, and
- Roger D. Kornberg*,¶
- *Department of Structural Biology and §Howard Hughes Medical Institute and Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305; and ‡Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital, Göteborg University, S-413 45 Göteborg, Sweden
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Contributed by Roger D. Kornberg
Abstract
Deletion of any one of three subunits of the yeast Mediator of transcriptional regulation, Med2, Pgd1 (Hrs1), and Sin4, abolished activation by Gal4–VP16 in vitro. By contrast, other Mediator functions, stimulation of basal transcription and of TFIIH kinase activity, were unaffected. A different but overlapping Mediator subunit dependence was found for activation by Gcn4. The genetic requirements for activation in vivo were closely coincident with those in vitro. A whole genome expression profile of a Δmed2 strain showed diminished transcription of a subset of inducible genes but only minor effects on “basal” transcription. These findings make an important connection between transcriptional activation in vitro and in vivo, and identify Mediator as a “global” transcriptional coactivator.
Footnotes
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↵ † L.C.M. and C.M.G. contributed equally to this work.
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↵ ¶ To whom reprint requests should be addressed. e-mail: kornberg{at}stanford.edu.
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A Commentary on this article begins on page 2.
- ABBREVIATIONS:
- CTD,
- C-terminal domain of RNA polymerase II;
- TAF,
- TATA boxing-binding protein associated factor
- Copyright © 1999, The National Academy of Sciences
