Article

Replication of heterochromatin: insights into mechanisms of epigenetic inheritance.

Whitehead Institute, Cambridge, MA, 02142, USA.
Chromosoma (impact factor: 3.85). 01/2006; 114(6):389-402. DOI:10.1007/s00412-005-0024-6 pp.389-402
Source: PubMed

ABSTRACT Heterochromatin is composed of tightly condensed chromatin in which the histones are deacetylated and methylated, and specific nonhistone proteins are bound. Additionally, in vertebrates and plants, the DNA within heterochromatin is methylated. As the heterochromatic state is stably inherited, replication of heterochromatin requires not only duplication of the DNA but also a reinstallment of the appropriate protein and DNA modifications. Thus replication of heterochromatin provides a framework for understanding mechanisms of epigenetic inheritance. In recent studies, roles have been identified for replication factors in reinstating heterochromatin, particularly functions for origin recognition complex, proliferating cell nuclear antigen, and chromatin-assembly factor 1 in recruiting the heterochromatin binding protein HP1, a histone methyltransferase, a DNA methyltransferase, and a chromatin remodeling complex. Potential mechanistic links between these factors are discussed. In some cells, replication of the heterochromatin is blocked, and in Drosophila this inhibition is mediated by a chromatin binding protein SuUR.

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Keywords

chromatin binding protein SuUR
 
chromatin-assembly factor 1
 
condensed chromatin
 
DNA methyltransferase
 
DNA modifications
 
factors
 
functions
 
heterochromatic state
 
heterochromatin
 
heterochromatin binding protein HP1
 
histones
 
methylated
 
origin recognition complex
 
plants
 
Potential mechanistic links
 
proliferating cell nuclear antigen
 
replication
 
replication factors
 
specific nonhistone proteins
 
understanding mechanisms
 

Julie A Wallace