title: Chromatin architecture of the human genome: gene-rich domains are enriched in open chromatin fibers.
abstract: We present an analysis of chromatin fiber structure across the human genome. Compact and open chromatin fiber structures were separated by sucrose sedimentation and their distributions analyzed by hybridization to metaphase chromosomes and genomic microarrays. We show that compact chromatin fibers originate from some sites of heterochromatin (C-bands), and G-bands (euchromatin). Open chromatin fibers correlate with regions of highest gene density, but not with gene expression since inactive genes can be in domains of open chromatin, and active genes in regions of low gene density can be embedded in compact chromatin fibers. Moreover, we show that chromatin fiber structure impacts on further levels of chromatin condensation. Regions of open chromatin fibers are cytologically decondensed and have a distinctive nuclear organization. We suggest that domains of open chromatin may create an environment that facilitates transcriptional activation and could provide an evolutionary constraint to maintain clusters of genes together along chromosomes.
authors.affiliation: MRC Human Genetics Unit, Edinburgh, EH4 2XU, Scotland.
authors.forename: Nick
authors.initials: N
authors.lastname: Gilbert
authors.forename: Shelagh
authors.initials: S
authors.lastname: Boyle
authors.forename: Heike
authors.initials: H
authors.lastname: Fiegler
authors.forename: Kathryn
authors.initials: K
authors.lastname: Woodfine
authors.forename: Nigel P
authors.initials: NP
authors.lastname: Carter
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Bickmore
mesh_terms: D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics* / Q000648:ultrastructure*; D002843:Chromatin / Q000235:genetics* / Q000648:ultrastructure*; D004276:DNA, Satellite / Q000235:genetics; D022041:Euchromatin / Q000235:genetics; D040461:Gene Components / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D005796:Genes / Q000235:genetics*; D015894:Genome, Human; D006570:Heterochromatin / Q000235:genetics; D006801:Humans; D008297:Male; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D002843:Chromatin; D004276:DNA, Satellite; D022041:Euchromatin; D006570:Heterochromatin