Recruitment of ERCC6 (CSB), EHMT2 (G9a), and NuRD to the promoter of rRNA gene

Stable Identifier
Reaction [binding]
Homo sapiens
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Transcription Termination Factor-I (TTF-I) is a sequence-specific binding protein that binds sites 5' (Tsp and T0 sites) and 3' (T1-10 site) of rRNA genes. As inferred from mouse, when TTF-I is bound to the promoter-proximal T0 site TTF-I either recruits ERCC6 (also known as Cockayne Syndrome Protein, CSB), EHMT2 (also known as histone methyltransferase G9a), and NuRD to activate expression (Shimono et al. 2005, Lebedev et al. 2008) or recruits the Nucleolar Remodeling Complex (NoRC) to repress expression. How one is selected over the other is unknown.
CHD4 and presumably the rest of the NuRD complex is associated with bivalent domains containing H3K4me3 (active chromatin mark) and H3K27me3 (inactive chromatin mark). ERCC6 and EHMT2 appear to cooperate to regulate activation of rRNA expression with ERCC6 mediating the transition to permissive chromatin (Lebedev et al. 2008) and EHMT2 mediating the transition to active chromatin, which involves the positional shift of one nucleosome at the promoter.
Literature References
PubMed ID Title Journal Year
18656484 Truncated Cockayne syndrome B protein represses elongation by RNA polymerase I

Lebedev, A, Scharffetter-Kochanek, K, Iben, S

J Mol Biol 2008
16186106 Microspherule protein 1, Mi-2beta, and RET finger protein associate in the nucleolus and up-regulate ribosomal gene transcription

Shimono, Y, Shimono, K, Ishiguro, N, Takahashi, M, Shimokata, K

J. Biol. Chem. 2005
12419226 CSB is a component of RNA pol I transcription

Vonesch, JL, Auriol, J, Egly, JM, Iben, S, Proietti de Santis, L, Bradsher, J, Grummt, I

Mol. Cell 2002
Inferred From
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