Epigenetic aspects of X-chromosome dosage compensation.
The X chromosomes of mammals and fruit flies exhibit unusual properties that have evolved to deal with the different dosages of X-linked genes in males (XY) and females (XX). The X chromosome dosage-compensation mechanisms discovered in these species are evolutionarily unrelated, but exhibit surprising parallels in their regulatory strategies. These features include the importance of noncoding RNAs, and epigenetic spreading of chromatin-modifying activities. Sex chromosomes have posed a fascinating puzzle for biologists. The dissimilar organization, gene content, and regulation of the X and Y chromosomes are thought to reflect selective forces acting on original pairs of identical chromosomes (1-3). The result in many organisms is a male-specific Y chromosome that has lost most of its original genetic content, and a difference in dosage of the X chromosome in males (XY) and females (XX).
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Howard Hughes Medical Institute, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Kuroda
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D000818:Animals; D002843:Chromatin / Q000378:metabolism; D004303:Dosage Compensation, Genetic; D004330:Drosophila / Q000235:genetics; D019143:Evolution, Molecular; D005260:Female; D018392:Genomic Imprinting; D006657:Histones / Q000378:metabolism; D006801:Humans; D008297:Male; D008322:Mammals / Q000235:genetics; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014960:X Chromosome / Q000235:genetics*
D002843:Chromatin; D006657:Histones; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D016601:RNA-Binding Proteins; D014157:Transcription Factors; C077885:XIST non-coding RNA