X-chromosome inactivation occurs at different times in different tissues of the post-implantation mouse embryo.
During mammalian development, one of the two X chromosomes in female embryos is randomly inactivated in the somatic cell in order to achieve gene dosage compensation. But is X inactivation established simultaneously or is it accomplished over time in a lineage-dependent fashion? We have examined this question in mouse embryos carrying an X-linked lacZ transgene. This transgene is subject to inactivation and the loss of beta-galactosidase activity provides a direct indication of X inactivation in individual cells. We find that X inactivation proceeds with different schedules in different somatic tissues, and the notochord, the heart, cranial mesoderm and the hindgut are among the last tissues to undergo X inactivation.
Department of Anatomy, University of Melbourne, Parkville, Victoria, Australia.
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Tan
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Williams
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Tam
D000818:Animals; D004303:Dosage Compensation, Genetic; D005314:Embryonic and Fetal Development / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D008040:Genetic Linkage; D005865:Gestational Age; D066298:In Vitro Techniques; D007763:Lac Operon; D051379:Mice; D008822:Mice, Transgenic; D009928:Organ Specificity; D011247:Pregnancy; D014960:X Chromosome; D001616:beta-Galactosidase / Q000235:genetics
D001616:beta-Galactosidase