title: X-chromosome inactivation during spermatogenesis is regulated by an Xist/Tsix-independent mechanism in the mouse.
abstract: Transcriptional inactivation of the single X chromosome occurs in spermatogenic cells during male meiosis in mammals and has been shown to be coincident with expression of the Xist gene in spermatogonia and spermatocytes in mice. However, male mice carrying an ablated Xist gene show normal fertility. Here we examined expression from the Xist locus during spermatogenesis in wild-type mice and detected sense (Xist), but not antisense (Tsix) transcripts. In addition, we examined expression and chromatin conformation of X-linked structural genes in meiotic and postmeiotic spermatogenic cells from wild-type and Xist(-) mice and found no differences associated with the absence of a functional Xist gene. These results, along with the formation of a morphologically normal XY body in primary spermatocytes in Xist(-) mice, indicate that a functional Xist gene is not required for X-chromosome inactivation during spermatogenesis and that this process is therefore regulated by a different mechanism than that which regulates X-chromosome inactivation in female embryonic cells.
authors.affiliation: Department of Biology, University of Texas at San Antonio, San Antonio, Texas 78249, USA. jmccarrey@utsa.edu
authors.forename: John R
authors.initials: JR
authors.lastname: McCarrey
authors.forename: Cathy
authors.initials: C
authors.lastname: Watson
authors.forename: Julia
authors.initials: J
authors.lastname: Atencio
authors.forename: G Charles
authors.initials: GC
authors.lastname: Ostermeier
authors.forename: York
authors.initials: Y
authors.lastname: Marahrens
authors.forename: Rudolf
authors.initials: R
authors.lastname: Jaenisch
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Krawetz
mesh_terms: D000818:Animals; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D004303:Dosage Compensation, Genetic; D017353:Gene Deletion; D005786:Gene Expression Regulation; D020868:Gene Silencing; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D062085:RNA, Long Noncoding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism*; D013090:Spermatocytes / Q000378:metabolism; D013091:Spermatogenesis / Q000235:genetics*; D013737:Testis / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D014960:X Chromosome / Q000235:genetics*; D014998:Y Chromosome / Q000235:genetics
chemical_list: D002843:Chromatin; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D022661:RNA, Untranslated; D014157:Transcription Factors; C465658:Tsix transcript, mouse; C077885:XIST non-coding RNA