title: Molecular coupling of Tsix regulation and pluripotency.
abstract: The reprogramming of X-chromosome inactivation during the acquisition of pluripotency in vivo and in vitro is accompanied by the repression of Xist, the trigger of X-inactivation, and the upregulation of its antisense counterpart Tsix. We have shown that key factors supporting pluripotency-Nanog, Oct4 and Sox2-bind within Xist intron 1 in undifferentiated embryonic stem cells (ESC) to repress Xist transcription. However, the relationship between transcription factors of the pluripotency network and Tsix regulation has remained unclear. Here we show that Tsix upregulation in embryonic stem cells depends on the recruitment of the pluripotent marker Rex1, and of the reprogramming-associated factors Klf4 and c-Myc, by the DXPas34 minisatellite associated with the Tsix promoter. Upon deletion of DXPas34, binding of the three factors is abrogated and the transcriptional machinery is no longer efficiently recruited to the Tsix promoter. Additional analyses including knockdown experiments further demonstrate that Rex1 is critically important for efficient transcription elongation of Tsix. Hence, distinct embryonic-stem-cell-specific complexes couple X-inactivation reprogramming and pluripotency, with Nanog, Oct4 and Sox2 repressing Xist to facilitate the reactivation of the inactive X, and Klf4, c-Myc and Rex1 activating Tsix to remodel Xist chromatin and ensure random X-inactivation upon differentiation. The holistic pattern of Xist/Tsix regulation by pluripotent factors that we have identified suggests a general direct governance of complex epigenetic processes by the machinery dedicated to pluripotency.
authors.affiliation: Unité de Génétique Moléculaire Murine, URA 2578, Institut Pasteur, 75724 Paris Cedex 15, France. pablo.navarro@ed.ac.uk
authors.forename: Pablo
authors.initials: P
authors.lastname: Navarro
authors.forename: Andrew
authors.initials: A
authors.lastname: Oldfield
authors.forename: Julie
authors.initials: J
authors.lastname: Legoupi
authors.forename: Nicola
authors.initials: N
authors.lastname: Festuccia
authors.forename: Agnès
authors.initials: A
authors.lastname: Dubois
authors.forename: Mikael
authors.initials: M
authors.lastname: Attia
authors.forename: Jon
authors.initials: J
authors.lastname: Schoorlemmer
authors.forename: Claire
authors.initials: C
authors.lastname: Rougeulle
authors.forename: Ian
authors.initials: I
authors.lastname: Chambers
authors.forename: Philip
authors.initials: P
authors.lastname: Avner
mesh_terms: D000818:Animals; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D018398:Homeodomain Proteins / Q000378:metabolism; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism; D008297:Male; D051379:Mice; D018598:Minisatellite Repeats / Q000235:genetics; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics*; D055748:SOXB1 Transcription Factors / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*; D015854:Up-Regulation / Q000235:genetics*; D049951:X Chromosome Inactivation / Q000235:genetics
chemical_list: D018398:Homeodomain Proteins; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; C489428:Myc protein, mouse; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D016271:Proto-Oncogene Proteins c-myc; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; C513672:Zfp42 protein, mouse; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; D014157:Transcription Factors; C465658:Tsix transcript, mouse; C077885:XIST non-coding RNA