Role of the Xist gene in X chromosome choosing.
In female mammals a "random choice" mechanism decides which of the two X chromosomes will be inactivated. It has been postulated that Xist is crucial for heterochromatinization and thus functions downstream of the choice mechanism. Here we report that females heterozygous for an internal deletion in the Xist gene, which includes part of exon 1 and extends to exon 5, undergo primary nonrandom inactivation of the wild-type X chromosome. The Xist gene, therefore, not only has a role in chromatin remodeling, but also includes an element required for X chromosome choosing. In conflict with the prevailing view of how choosing occurs, the element identified by the deletion plays a positive role in the choice mechanism and forces a reassessment of how X chromosome choosing is thought to occur.
Marahrens
Y
Y
Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA.
Loring
J
J
Jaenisch
R
R
D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight; D004303:Dosage Compensation, Genetic; D005091:Exons / Q000235:genetics; D005260:Female; D005333:Fetus; D018507:Gene Expression Regulation, Developmental; D006579:Heterozygote; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D008957:Models, Genetic; D010641:Phenotype; D062085:RNA, Long Noncoding; D012333:RNA, Messenger / Q000032:analysis; D022661:RNA, Untranslated; D017384:Sequence Deletion; D014157:Transcription Factors / Q000235:genetics*; D014960:X Chromosome / Q000235:genetics*
D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D022661:RNA, Untranslated; D014157:Transcription Factors; C077885:XIST non-coding RNA