title: The 5' boundary of the human apolipoprotein B chromatin domain in intestinal cells.
abstract: The 5' boundary of the chromosomal domain of the human apolipoprotein B (apoB) gene in intestinal cells has been localized and characterized. It is composed of two kinds of boundary elements; the first, functional boundary is an insulator activity exhibited by a 1.8 kb DNA fragment located between -58 and -56 kb upstream of the human apoB promoter. In this region, an enhancer-blocking activity has been mapped to a CTCF binding site that is located upstream of two apoB intestinal enhancers (IEs), the 315 IE and the 485 IE. The CTCF site represents a boundary between two types of chromatin structure: an open, DNaseI-sensitive region 3' of the CTCF site containing the intestinal regulatory elements and a closed, DNaseI-resistant region 5' of the CTCF site. The 1.8 kb fragment harboring the CTCF site also insulated mini-white transgenes against position effects in Drosophila melanogaster. The second, structural boundary is represented by a nuclear matrix attachment region (MAR), situated about 3 kb 5' of the CTCF site. This MAR may represent the 5' anchorage site for a chromosomal loop that functions to bring the intestinal regulatory elements closer to the apoB promoter.
authors.affiliation: Research Institute, Palo Alto Medical Foundation, Palo Alto, California 94301, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Antes
authors.forename: S J
authors.initials: SJ
authors.lastname: Namciu
authors.forename: R E
authors.initials: RE
authors.lastname: Fournier
authors.forename: B
authors.initials: B
authors.lastname: Levy-Wilson
mesh_terms: D020121:5' Untranslated Regions / Q000737:chemistry* / Q000235:genetics; D000818:Animals; D001055:Apolipoproteins B / Q000737:chemistry / Q000235:genetics*; D001482:Base Composition; D001665:Binding Sites / Q000235:genetics; D000076246:CCCTC-Binding Factor; D019556:COS Cells; D018938:Caco-2 Cells / Q000737:chemistry / Q000378:metabolism*; D002843:Chromatin / Q000737:chemistry / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015246:Deoxyribonuclease EcoRI / Q000235:genetics; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics; D004742:Enhancer Elements, Genetic; D005260:Female; D006801:Humans; D015530:Nuclear Matrix / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins; D017434:Protein Structure, Tertiary / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D020121:5' Untranslated Regions; D001055:Apolipoproteins B; D000076246:CCCTC-Binding Factor; C000619697:CTCF protein, human; D002843:Chromatin; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; C092281:PSI protein, Drosophila; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D015246:Deoxyribonuclease EcoRI