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NoRC‐dependent nucleosome positioning silences rRNA genes
Author(s) -
Li Junwei,
Längst Gernot,
Grummt Ingrid
Publication year - 2006
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7601454
Subject(s) - biology , nucleosome , genetics , gene , ribosomal rna , evolutionary biology , computational biology , histone
Previous studies have established that the Snf2h‐containing chromatin remodeling complex NoRC mediates epigenetic silencing of a subset of rRNA genes (rDNA) by recruiting enzymatic activities that modify histones and methylate DNA. Here we have analyzed nucleosome positions at the murine rDNA promoter and show that active and silent rDNA copies are characterized not only by specific epigenetic marks but also by differently positioned nucleosomes. At active genes the promoter‐bound nucleosome covers nucleotides from −157 to −2, whereas at silent genes the nucleosome is positioned 25 nucleotides further downstream. We provide evidence that NoRC is the molecular machine that shifts the promoter‐bound nucleosome downstream of the transcription start site into a translational position that is unfavorable for transcription complex formation.