Sex-specific gene expression during meiotic prophase I: Xlr (X linked, lymphocyte regulated), not its male homologue Xmr (Xlr related, meiosis regulated), is expressed in mouse oocytes.
The Xmr (Xlr related, meiosis regulated) gene product is abundantly expressed in primary spermatocytes and is notably associated with nonrecombining segments of sex chromosomes in the XY body. Here we determined whether Xmr was expressed in meiotic oocytes. This was done by reverse transcription-polymerase chain reaction and cDNA sequencing, Western blot analysis, and immunocytochemistry. Unexpectedly, no Xmr message was detected in mouse fetal oocytes. Instead, Xlr (X linked, lymphocyte regulated), a closely related gene expressed in fetal thymus cells at the time of antigen-receptor gene rearrangement, was expressed in oocytes throughout meiotic prophase I. These findings indicate a sex-specific expression of two closely related members of the Xlr gene family during meiotic prophase I. The XLR protein may provide a useful marker for studies on chromatin condensation or DNA recombination in oocytes. In addition, because of the localization of the Xlr sequence family on the mouse X chromosome, the human equivalent of Xlr is a candidate gene for premature ovarian failure.
Escalier
Denise
D
Laboratoire de Cytologie et Histologie, EA1533, 45, Rue des Saints Pères, 75270 Paris Cedex 06, France. denise.escalier@biomedicale.univ-paris5.fr
Eloy
Laure
L
Garchon
Henri-Jean
HJ
D000818:Animals; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008297:Male; D008540:Meiosis; D051379:Mice; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D010053:Ovary / Q000166:cytology / Q000196:embryology / Q000502:physiology; D011418:Prophase / Q000235:genetics; D012727:Sex Characteristics; D012737:Sex Factors; D013094:Spermatozoa / Q000502:physiology
D009687:Nuclear Proteins; C085792:Slx protein, mouse; C490091:XLRL protein, human; C490092:Xlr nuclear protein, mouse