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Evolution from XIST-independent to XIST-controlled X-chromosome inactivation : epigenetic modifications in distantly related mammals

dc.contributor.authorChaumeil, Julieen_ZA
dc.contributor.authorWaters, Paul D.en_ZA
dc.contributor.authorKoina, Eddaen_ZA
dc.contributor.authorGilbert, Clementen_ZA
dc.contributor.authorRobinson, Terence J.en_ZA
dc.contributor.authorGraves, Jennifer A. Marshallen_ZA
dc.date.accessioned2011-05-25T08:49:47Z
dc.date.available2011-05-25T08:49:47Z
dc.date.issued2011-04-25
dc.identifier.citationChaumeil, J. et al. 2011. Evolution from XIST-independent to XIST-controlled X-chromosome inactivation : epigenetic modifications in distantly related mammals. PLoS ONE, 6(4): e19040, doi:10.1371/journal.pone.0019040.
dc.identifier.issn1932-6203 (online)
dc.identifier.otherdoi:10.1371/journal.pone.0019040
dc.identifier.urihttp://hdl.handle.net/10019.1/14689
dc.descriptionCITATION: Chaumeil, J. et al. 2011. Evolution from XIST-independent to XIST-controlled X-chromosome inactivation : epigenetic modifications in distantly related mammals. PLoS ONE, 6(4): e19040, doi:10.1371/journal.pone.0019040.
dc.descriptionThe original publication is available at http://journals.plos.org/plosone
dc.description.abstractX chromosome inactivation (XCI) is the transcriptional silencing of one X in female mammals, balancing expression of X genes between females (XX) and males (XY). In placental mammals non-coding XIST RNA triggers silencing of one X (Xi) and recruits a characteristic suite of epigenetic modifications, including the histone mark H3K27me3. In marsupials, where XIST is missing, H3K27me3 association seems to have different degrees of stability, depending on cell-types and species. However, the complete suite of histone marks associated with the Xi and their stability throughout cell cycle remain a mystery, as does the evolution of an ancient mammal XCI system. Our extensive immunofluorescence analysis (using antibodies against specific histone modifications) in nuclei of mammals distantly related to human and mouse, revealed a general absence from the mammalian Xi territory of transcription machinery and histone modifications associated with active chromatin. Specific repressive modifications associated with XCI in human and mouse were also observed in elephant (a distantly related placental mammal), as was accumulation of XIST RNA. However, in two marsupial species the Xi either lacked these modifications (H4K20me1), or they were restricted to specific windows of the cell cycle (H3K27me3, H3K9me2). Surprisingly, the marsupial Xi was stably enriched for modifications associated with constitutive heterochromatin in all eukaryotes (H4K20me3, H3K9me3). We propose that marsupial XCI is comparable to a system that evolved in the common therian (marsupial and placental) ancestor. Silent chromatin of the early inactive X was exapted from neighbouring constitutive heterochromatin and, in early placental evolution, was augmented by the rise of XIST and the stable recruitment of specific histone modifications now classically associated with XCI. © 2011 Chaumeil et al.
dc.description.urihttp://journals.plos.org/plosone/article?id=10.1371/journal.pone.0019040
dc.format.extent11 pages
dc.language.isoen
dc.publisherPublic Library of Science
dc.subjectEpigenesisen_ZA
dc.subjectGenetic regulationen_ZA
dc.subjectMammals -- Geneticsen_ZA
dc.titleEvolution from XIST-independent to XIST-controlled X-chromosome inactivation : epigenetic modifications in distantly related mammalsen_ZA
dc.typeArticle
dc.description.versionPublisher's version
dc.rights.holderAuthors retain copyright


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