The Mediator subunit MED23 couples H2B mono-ubiquitination to transcriptional control and cell fate determination.
The Mediator complex orchestrates multiple transcription factors with the Pol II apparatus for precise transcriptional control. However, its interplay with the surrounding chromatin remains poorly understood. Here, we analyze differential histone modifications between WT and MED23(-/-) (KO) cells and identify H2B mono-ubiquitination at lysine 120 (H2Bub) as a MED23-dependent histone modification. Using tandem affinity purification and mass spectrometry, we find that MED23 associates with the RNF20/40 complex, the enzyme for H2Bub, and show that this association is critical for the recruitment of RNF20/40 to chromatin. In a cell-free system, Mediator directly and substantially increases H2Bub on recombinant chromatin through its cooperation with RNF20/40 and the PAF complex. Integrative genome-wide analyses show that MED23 depletion specifically reduces H2Bub on a subset of MED23-controlled genes. Importantly, MED23-coupled H2Bub levels are oppositely regulated during myogenesis and lung carcinogenesis. In sum, these results establish a mechanistic link between the Mediator complex and a critical chromatin modification in coordinating transcription with cell growth and differentiation.
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China.
Xiao
X
Yao
Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA.
Zhanyun
Z
Tang
Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China.
Xing
X
Fu
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China.
Jingwen
J
Yin
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China.
Yan
Y
Liang
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China.
Chonghui
C
Li
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China.
Huayun
H
Li
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China.
Qing
Q
Tian
Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA.
Robert G
RG
Roeder
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China gwang@sibcb.ac.cn.
Gang
G
Wang
D000818:Animals; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D055106:Genome-Wide Association Study; D006657:Histones / Q000378:metabolism*; D056892:Mediator Complex / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D024510:Muscle Development / Q000235:genetics / Q000502:physiology; D054875:Ubiquitination / Q000235:genetics / Q000502:physiology
D006657:Histones; C541034:Med23 protein, mouse; D056892:Mediator Complex
H2B mono‐ubiquitination; Mediator MED23; RNF20 and RNF40; myogenesis; tumorigenesis