Transcription of the sex-determining region genes Sry and Zfy in the mouse preimplantation embryo.
We have confirmed the faster growth of male preimplantation mouse embryos. We have also studied the transcription of Y chromosomal genes postulated to have a role in sex determination, using the highly sensitive technique of reverse-transcription polymerase chain reaction at these early stages. We find that two sex-determining region genes, Sry and Zfy, are transcribed during mouse preimplantation development, while the Zfy homologs Zfx and Zfa and a sex-determining region gene originally called A1s9 (now called Ube1y-1) are not. We also show that the anti-Müllerian hormone gene, which contains a Sry consensus binding element in its 5' promoter region, is not transcribed at this time. Developmental curves show that Sry and Zfy are expressed commencing at the two-cell stage. These results suggest that mammalian sex determination starts prior to gonad differentiation.
Zwingman
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Steele Memorial Children's Research Center, Department of Pediatrics, University of Arizona, Tucson 85724.
Erickson
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RP
Boyer
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Ao
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D000818:Animals; D001483:Base Sequence; D001755:Blastocyst / Q000502:physiology*; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL / Q000196:embryology; D008815:Mice, Inbred Strains / Q000196:embryology*; D008969:Molecular Sequence Data; D012732:Sex Determination Analysis; D012733:Sex Differentiation / Q000235:genetics*; D014158:Transcription, Genetic; D014998:Y Chromosome