Transcription of Y- and X-linked genes in preimplantation ovine embryos.
Because male ovine embryos develop faster than female embryos, the transcription of SRY and ZFY, two genes located on the Y chromosome, was examined in preimplantation stages using the reverse transcriptase polymerase chain reaction (RT-PCR). RNA was extracted from pools of ovine embryos matured and fertilized in vitro then cultured in synthetic oviduct fluid medium and recovered from 24 to 207 hr post-insemination (two-cell up to hatched blastocyst stage). Since primers used to amplify ZFY also amplify the homologue ZFX, located on the X chromosome, transcripts were differentiated by digestion with restriction enzymes. ZFY and ZFX transcripts were present in all stages examined following RT-PCR, whereas transcripts for SRY were undetectable in all investigated stages following either RT nested PCR or Southern analysis. The presence of ZFY transcripts suggests that Y chromosome is transcriptionally active during early ovine preimplantation development. The possible relationship between a faster growth of male embryos and the transcription of Y-linked genes at early stages of development is discussed.
Génétique Moléculaire et Cellulaire, INRA-ENVA, Maisons-Alfort, France.
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Bernardi
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Cotinot
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Payen
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Delouis
D000818:Animals; D001755:Blastocyst; D002417:Cattle; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008040:Genetic Linkage; D008297:Male; D011247:Pregnancy; D012756:Sheep / Q000196:embryology; D014158:Transcription, Genetic; D014960:X Chromosome / Q000235:genetics*; D014998:Y Chromosome / Q000235:genetics*