Human Mediator Subunit MED26 Functions as a Docking Site for Transcription Elongation Factors

详细信息    查看全文

• 作者：Hidehisa Takahashi¹ ; Tari  ; J. Parmely¹ ; Shigeo Sato¹ ; Chieri Tomomori-Sato¹ ; Charles  ; A.S. Banks¹ ; Stephanie  ; E. Kong¹ ; Henrietta Szutorisz¹ ; Selene  ; K. Swanson¹ ; Skylar Martin-Brown¹ ; Michael  ; P. Washburn¹ ; ² ; Laurence Florens¹ ; Chris  ; W. Seidel¹ ; Chengqi Lin¹ ; Edwin  ; R. Smith¹ ; Ali Shilatifard¹ ; Ronald  ; C. Conaway¹ ; ³ ; Joan  ; W. Conaway¹ ; ³ ; ^{jlc@stowers.org"" rel=""nofollow}
• 刊名：Cell
• 出版年：2011
• 出版时间：8 July 2011
• 年：2011
• 卷：146
• 期：1
• 页码：92-104
• 全文大小：1535 K

文摘

Summary

Promoter-proximal pausing by initiated RNA polymerase II (Pol II) and regulated release of paused polymerase into productive elongation has emerged as a major mechanism of transcription activation. Reactivation of paused Pol II correlates with recruitment of super-elongation complexes (SECs) containing ELL/EAF family members, P-TEFb, and other proteins, but the mechanism of their recruitment is an unanswered question. Here, we present evidence for a role of human Mediator subunit MED26 in this process. We identify in the conserved N-terminal domain of MED26 overlapping docking sites for SEC and a second ELL/EAF-containing complex, as well as general initiation factor TFIID. In addition, we present evidence consistent with the model that MED26 can function as a molecular switch that interacts first with TFIID in the Pol II initiation complex and then exchanges TFIID for complexes containing ELL/EAF and P-TEFb to facilitate transition of Pol II into the elongation stage of transcription.