Chromatin domains, insulators, and the regulation of gene expression

摘要: The DNA sequence elements called insulators have two basic kinds of properties. Barrier block the propagation heterochromatic structures into adjacent euchromatin. Enhancer blocking interfere with interaction between an enhancer and promoter when placed them. We dissected a compound insulator element found at 5' end chicken β-globin locus, which possesses both activities. insulation is mediated by binding proteins: USF1/USF2, heterodimer recruits multiple enzyme complexes capable marking histone on nucleosomes 'activating' marks, Vezf1, protects against methylation. that region upstream maintained in its silent state dicer-dependent mechanism, suggesting mechanism for Vezf1 function insulator. conferred site CTCF. Consistent this property, CTCF was some years ago to be essential imprinted expression Igf2/H19 locus. Work many laboratories has since demonstrated helps stabilize long-range interactions nucleus. recently shown case human insulin locus such interaction, over distance ~300kb, can result stimulation target gene itself important secretion. This article part Special Issue entitled: Chromatin time space.