title: Xist RNA is confined to the nuclear territory of the silenced X chromosome throughout the cell cycle.
abstract: In mammalian female cells, one X chromosome is inactivated to prevent a dose difference in the expression of X-encoded proteins between males and females. Xist RNA, required for X chromosome inactivation, is transcribed from the future inactivated X chromosome (Xi), where it spreads in cis, to initiate silencing. We have analyzed Xist RNA transcription and localization throughout the cell cycle. It was found that Xist transcription is constant and that the mature RNA remains attached to the Xi throughout mitosis. Diploid and tetraploid cell lines with an MS2-tagged Xist gene were used to investigate spreading of Xist. Most XXXX(MS2) tetraploid mouse embryonic stem (ES) cells inactivate the X(MS2) chromosome and one other X chromosome. Analysis of cells with two Xi's indicates that Xist RNA is retained by the Xi of its origin and does not spread in trans. Also, in XX(MS2) diploid mouse ES cells with an autosomal Xist transgene, there is no trans exchange of Xist RNA from the Xi to the autosome. We propose that Xist RNA does not dissociate from the Xi of its origin, which precludes a model of diffusion-mediated trans spreading of Xist RNA.
authors.affiliation: Department of Cell Biology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Iris
authors.initials: I
authors.lastname: Jonkers
authors.forename: Kim
authors.initials: K
authors.lastname: Monkhorst
authors.forename: Eveline
authors.initials: E
authors.lastname: Rentmeester
authors.forename: J Anton
authors.initials: JA
authors.lastname: Grootegoed
authors.forename: Frank
authors.initials: F
authors.lastname: Grosveld
authors.forename: Joost
authors.initials: J
authors.lastname: Gribnau
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000235:genetics; D002454:Cell Differentiation; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D051379:Mice; D008957:Models, Genetic; D011003:Ploidies; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014960:X Chromosome / Q000235:genetics*; D049951:X Chromosome Inactivation
chemical_list: D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; C077885:XIST non-coding RNA