title: CTCF-dependent chromatin insulator is linked to epigenetic remodeling.
abstract: Chromatin insulators are boundary elements between distinctly regulated, neighboring chromosomal domains, and they function by blocking the effects of nearby enhancers in a position-dependent manner. Here, we show that the SNF2-like chromodomain helicase protein CHD8 interacts with the insulator binding protein CTCF. Chromatin immunoprecipitation analysis revealed that CHD8 was present at known CTCF target sites, such as the differentially methylated region (DMR) of H19, the locus control region of beta-globin, and the promoter region of BRCA1 and c-myc genes. RNA interference-mediated knockdown of CHD8 significantly abolished the H19 DMR insulator activity that depends highly on CTCF, leading to reactivation of imprinted IGF2 from chromosome of maternal origin. Further, the lack of CHD8 affected CpG methylation and histone acetylation around the CTCF binding sites, adjacent to heterochromatin, of BRCA1 and c-myc genes. These findings provide insight into the role of CTCF-CHD8 complex in insulation and epigenetic regulation at active insulator sites.
authors.affiliation: Department of Regeneration Medicine, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Ishihara
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Oshimura
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Nakao
mesh_terms: D000818:Animals; D001665:Binding Sites; D000076246:CCCTC-Binding Factor; D002478:Cells, Cultured; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly; D004265:DNA Helicases / Q000378:metabolism; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000235:genetics; D044127:Epigenesis, Genetic; D018392:Genomic Imprinting / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D038101:Insulator Elements / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000076246:CCCTC-Binding Factor; C000619697:CTCF protein, human; D002843:Chromatin; C000619698:Ctcf protein, mouse; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; C515814:duplin protein, mouse; D004265:DNA Helicases