X-chromosome inactivation during spermatogenesis is regulated by an Xist/Tsix-independent mechanism in the mouse.
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.
McCarrey
John R
JR
Department of Biology, University of Texas at San Antonio, San Antonio, Texas 78249, USA. jmccarrey@utsa.edu
Watson
Cathy
C
Atencio
Julia
J
Ostermeier
G Charles
GC
Marahrens
York
Y
Jaenisch
Rudolf
R
Krawetz
Stephen A
SA
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
D002843:Chromatin; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D022661:RNA, Untranslated; D014157:Transcription Factors; C465658:Tsix transcript, mouse; C077885:XIST non-coding RNA