title: Identification of a novel distal control region upstream of the human steroidogenic acute regulatory protein (StAR) gene that participates in SF-1-dependent chromatin architecture.
abstract: StAR (steroidogenic acute regulatory protein) mediates the transport of cholesterol from the outer to the inner mitochondrial membrane, the process of which is the rate-limiting step for steroidogenesis. Transcriptional regulation of the proximal promoter of the human StAR gene has been well characterized, whereas analysis of its distal control region has not. Recently, we found that SF-1 (steroidogenic factor 1) induced the differentiation of mesenchymal stem cells (MSCs) into steroidogenic cells with the concomitant strong induction of StAR expression. Here, we show, using differentiated MSCs, that StAR expression is regulated by a novel distal control region. Using electrophoretic mobility shift (EMSA) and chromatin immunoprecipitation (ChIP) assays, we identified novel SF-1 binding sites between 3,000 and 3,400 bp upstream of StAR. A luciferase reporter assay revealed that the region worked as a strong regulator to exert maximal transcription of StAR. ChIP analysis of histone H3 revealed that upon SF-1 expression, nucleosome eviction took place at the SF-1 binding sites, not only in the promoter but also in the distal SF-1 binding sites. Chromosome conformation capture analysis revealed that the region upstream of StAR formed a chromatin loop both in the differentiated MSCs and in KGN cells, a human granulosa cell tumor cell line, where SF-1 is endogenously expressed. Finally, SF-1 knockdown resulted in disrupted formation of this chromatin loop in KGN cells. These results indicate that the novel distal control region participate in StAR activation through SF-1 dependent alterations of chromatin structure, including histone eviction and chromatin loop formation.
authors.affiliation: Department of Biochemistry, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mizutani
authors.forename: Takashi
authors.initials: T
authors.lastname: Yazawa
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Ju
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Imamichi
authors.forename: Miki
authors.initials: M
authors.lastname: Uesaka
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Inaoka
authors.forename: Kaoru
authors.initials: K
authors.lastname: Matsuura
authors.forename: Yasue
authors.initials: Y
authors.lastname: Kamiki
authors.forename: Masaya
authors.initials: M
authors.lastname: Oki
authors.forename: Akihiro
authors.initials: A
authors.lastname: Umezawa
authors.forename: Kaoru
authors.initials: K
authors.lastname: Miyamoto
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D017124:Conserved Sequence; D024202:Electrophoretic Mobility Shift Assay; D019143:Evolution, Molecular; D006657:Histones / Q000378:metabolism; D006801:Humans; D019901:Locus Control Region / Q000235:genetics*; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D054339:Steroidogenic Factor 1 / Q000378:metabolism*; D015533:Transcriptional Activation; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D002843:Chromatin; D006657:Histones; D010750:Phosphoproteins; D054339:Steroidogenic Factor 1; D000098682:Steroidogenic Acute Regulatory Protein