Corepressor MMTR/DMAP1 is involved in both histone deacetylase 1- and TFIIH-mediated transcriptional repression.
A transcription corepressor, MAT1-mediated transcriptional repressor (MMTR), was found in mouse embryonic stem cell lines. MMTR orthologs (DMAP1) are found in a wide variety of life forms from yeasts to humans. MMTR down-regulation in differentiating mouse embryonic stem cells in vitro resulted in activation of many unrelated genes, suggesting its role as a general transcriptional repressor. In luciferase reporter assays, the transcriptional repression activity resided at amino acids 221 to 468. Histone deacetylase 1 (HDAC1) interacts with MMTR both in vitro and in vivo and also interacts with MMTR in the nucleus. Interestingly, MMTR activity was only partially rescued by competition with dominant-negative HDAC1(H141A) or by treatment with an HDAC inhibitor, trichostatin A (TSA). To identify the protein responsible for HDAC1-independent MMTR activity, we performed a yeast two-hybrid screen with the full-length MMTR coding sequence as bait and found MAT1. MAT1 is an assembly/targeting factor for cyclin-dependent kinase-activating kinase which constitutes a subcomplex of TFIIH. The coiled-coil domain in the middle of MAT1 was confirmed to interact with the C-terminal half of MMTR, and the MMTR-mediated transcriptional repression activity was completely restored by MAT1 in the presence of TSA. Moreover, intact MMTR was required to inhibit phosphorylation of the C-terminal domain in the RNA polymerase II largest subunit by TFIIH kinase in vitro. Taken together, these data strongly suggest that MMTR is part of the basic cellular machinery for a wide range of transcriptional regulation via interaction with TFIIH and HDAC.
Kang
Bong Gu
BG
Department of Life Science, College of Natural Sciences, Hanyang University, Haengdang 17, Sungdong-gu, Seoul 133-791, South Korea.
Shin
June Ho
JH
Yi
Jae Kyu
JK
Kang
Ho Chul
HC
Lee
Jong Joo
JJ
Heo
Hyen Seok
HS
Chae
Ji Hyung
JH
Shin
Incheol
I
Kim
Chul Geun
CG
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins; D002460:Cell Line; D056748:Cyclin H; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D051758:Transcription Factor TFIIH / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D014158:Transcription, Genetic; D000095043:Cyclin-Dependent Kinase-Activating Kinase
C534751:CCNH protein, human; D002352:Carrier Proteins; C534752:Ccnh protein, mouse; D018797:Cell Cycle Proteins; D056748:Cyclin H; D016213:Cyclins; C485852:Dmap1 protein, mouse; C514215:MNAT1 protein, human; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D051758:Transcription Factor TFIIH; D018844:Cyclin-Dependent Kinases; D012319:RNA Polymerase II; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D000095043:Cyclin-Dependent Kinase-Activating Kinase