Nucleolar Remodelling Complex (NoRC) binds intergenic region of rDNA

Stable Identifier
Reaction [binding]
Homo sapiens
Binding of Nucleolar Chromatin Remodeling Complex to Intergenic Spacer of rRNA Gene
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As inferred from mouse cell models, the Nucleolar Remodeling Complex (NoRC) comprises TIP5 (BAZ2A) and the chromatin remodeller SNF2H (SMARCA5). The TAM domain of TIP5 (BAZ2A) binds promoter-associated RNA (pRNA) transcribed from the intergenic spacer region of rDNA (Anosova et al. 2015). Binding is not sequence-specific but depends on the secondary structure of the RNA. The pRNA bound by TIP5 is required to direct the complex to the main promoter of the rRNA gene possibly by triple helix formation between pRNA and the rDNA. The PHD domain of TIP5 binds histone H4 acetylated at lysine-16. Transcription Termination Factor-I (TTF-I) binds to a promoter-proximal terminator (T0 site) in the rDNA and interacts with the TIP5 subunit of NoRC. NoRC also interacts with the SIN3-HDAC complex, HDAC1, HDAC2, DNMT1, and DNMT3B. DNMT3B interacts with a triple helix formed by pRNA and the rDNA. HDAC1, DNMT1, and DNMT3B have been shown to be required for proper DNA methylation of silenced rRNA gene copies, although the catalytic activity of DNMT3B was not required (Majumder et al. 2006).

Literature References
PubMed ID Title Journal Year
16735507 Role of DNA methyltransferases in regulation of human ribosomal RNA gene transcription

Majumder, S, Ghoshal, K, Datta, J, Smith, DS, Bai, S, Jacob, ST

J. Biol. Chem. 2006
25916849 A novel RNA binding surface of the TAM domain of TIP5/BAZ2A mediates epigenetic regulation of rRNA genes

Anosova, I, Melnik, S, Tripsianes, K, Kateb, F, Grummt, I, Sattler, M

Nucleic Acids Res. 2015
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