title: The human X-inactivation centre is not required for maintenance of X-chromosome inactivation.
abstract: X-chromosome inactivation occurs early in mammalian female development to achieve dosage compensation with males. Although it is widely accepted that this inactivation requires the presence in cis of the X-inactivation centre (XIC), it is not known whether the XIC is required for the initiation, promulgation or maintenance of X inactivation. The XIST gene, which is localized within the XIC interval on both the human and mouse X chromosomes, is constitutively expressed from inactive X chromosomes, suggesting a possible role in the maintenance of X inactivation. To address whether the presence of the XIC, including the XIST gene, is continuously required for the maintenance of X-chromosome inactivation, we have analysed the transcriptional activity of a number of X-linked genes in mouse/human somatic cell hybrids retaining an intact human inactive X chromosome or derivatives of the inactive X chromosome lacking the XIC. Genes subject to X inactivation remain transcriptionally silent despite the loss of the XIC, demonstrating that the presence of the XIC is not required for the maintenance of X inactivation in somatic cells.
authors.affiliation: Department of Genetics, Case Western Reserve University, Cleveland, Ohio 44106.
authors.forename: C J
authors.initials: CJ
authors.lastname: Brown
authors.forename: H F
authors.initials: HF
authors.lastname: Willard
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D004303:Dosage Compensation, Genetic; D005260:Female; D006801:Humans; D006822:Hybrid Cells; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic; D014960:X Chromosome
chemical_list: D017931:DNA Primers; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D014157:Transcription Factors; C077885:XIST non-coding RNA