title: RevSex duplication-induced and sex-related differences in the SOX9 regulatory region chromatin landscape in human fibroblasts.
abstract: It was recently shown that duplications of the RevSex element, located 0.5 Mb upstream of SOX9, cause XX-disorder of sex development (DSD), and that deletions cause XY-DSD. To explore how a 148 kb RevSex duplication could have turned on gonadal SOX9 expression in the absence of SRY in an XX-male, we examined the chromatin landscape in primary skin fibroblast cultures from the index, his RevSex duplication-carrier father and six controls. The ENCODE project supports the notion that chromatin state maps show overlap between different cell types, i.e., that our study of fibroblasts could be of biological relevance. We examined the SOX9 regulatory region by high-resolution ChIP-on-chip experiments (a kind of "chromatin-CGH") and DNA methylation investigations. The RevSex duplication was associated with chromatin changes predicting better accessibility of the SRY-responsive TESCO enhancer region 14-15 kb upstream of SOX9. Four kb downstream of the TESCO evolutionary conserved region, a peak of the enhancer/promoter-associated H3K4me3 mark was found together with a major dip of the repressive H3K9me3 chromatin mark. Similar differences were also found when three control males were compared with three control females. A marked male/female difference was a more open chromatin signature in males starting ~400 kb upstream of SOX9 and increasing toward the SOX9 promoter. In the RevSex duplication-carrier father, two positions of DNA hypomethylation were also found, one corresponding to the H3K4me3 peak mentioned above. Our results suggest that the RevSex duplication could operate by inducing long-range epigenetic changes. Furthermore, the differences in chromatin state maps between males and females suggest that the Y chromosome or X chromosome dosage may affect chromatin conformation, i.e., that sex-dependent gene regulation may take place by chromatin modification.
authors.affiliation: Center for Medical Genetics and Molecular Medicine; Haukeland University Hospital; Bergen, Norway.
authors.forename: Helle
authors.initials: H
authors.lastname: Lybæk
authors.affiliation: Department of Human Genetics; Radboud University Nijmegen Medical Centre; Nijmegen, the Netherlands.
authors.forename: Diederik
authors.initials: D
authors.lastname: de Bruijn
authors.affiliation: Department of Human Genetics; Radboud University Nijmegen Medical Centre; Nijmegen, the Netherlands.
authors.forename: Anke H A
authors.initials: AH
authors.lastname: den Engelsman-van Dijk
authors.affiliation: Institute for Molecular Bioscience; University of Queensland; Brisbane, QLD Australia.
authors.forename: Darya
authors.initials: D
authors.lastname: Vanichkina
authors.affiliation: Center for Medical Genetics and Molecular Medicine; Haukeland University Hospital; Bergen, Norway.
authors.forename: Chirag
authors.initials: C
authors.lastname: Nepal
authors.affiliation: Center for Medical Genetics and Molecular Medicine; Haukeland University Hospital; Bergen, Norway.
authors.forename: Atle
authors.initials: A
authors.lastname: Brendehaug
authors.affiliation: Center for Medical Genetics and Molecular Medicine; Haukeland University Hospital; Bergen, Norway.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Houge
mesh_terms: D058489:46, XX Disorders of Sex Development / Q000235:genetics*; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism*; D019175:DNA Methylation; D005260:Female; D005347:Fibroblasts / Q000378:metabolism*; D020440:Gene Duplication; D006061:Gonadal Dysgenesis, 46,XY / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D008297:Male; D011401:Promoter Regions, Genetic; D055758:SOX9 Transcription Factor / Q000235:genetics*; D012737:Sex Factors
chemical_list: D002843:Chromatin; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human
keywords: 46,XX DSD; ChIP-on-chip; RevSex duplication; SOX9; TESCO; chromatin; epigenetics; sex determination