Ring1B compacts chromatin structure and represses gene expression independent of histone ubiquitination.
Mol Cell
; 38(3): 452-64, 2010 May 14.
Article
in En
| MEDLINE
| ID: mdl-20471950
ABSTRACT
How polycomb group proteins repress gene expression in vivo is not known. While histone-modifying activities of the polycomb repressive complexes (PRCs) have been studied extensively, in vitro data have suggested a direct activity of the PRC1 complex in compacting chromatin. Here, we investigate higher-order chromatin compaction of polycomb targets in vivo. We show that PRCs are required to maintain a compact chromatin state at Hox loci in embryonic stem cells (ESCs). There is specific decompaction in the absence of PRC2 or PRC1. This is due to a PRC1-like complex, since decompaction occurs in Ring1B null cells that still have PRC2-mediated H3K27 methylation. Moreover, we show that the ability of Ring1B to restore a compact chromatin state and to repress Hox gene expression is not dependent on its histone ubiquitination activity. We suggest that Ring1B-mediated chromatin compaction acts to directly limit transcription in vivo.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Repressor Proteins
/
Histones
/
Protein Processing, Post-Translational
/
Chromatin Assembly and Disassembly
/
Embryonic Stem Cells
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Mol Cell
Journal subject:
BIOLOGIA MOLECULAR
Year:
2010
Type:
Article
Affiliation country:
United kingdom