Chromatin modifications on the inactive X chromosome.
In female mammals, one X chromosome is transcriptionally silenced to achieve dosage compensation between XX females and XY males. This process, known as X-inactivation, occurs early in development, such that one X chromosome is silenced in every cell. Once X-inactivation has occurred, the inactive X chromosome is marked by a unique set of epigenetic features that distinguishes it from the active X chromosome and autosomes. These modifications appear sequentially during the transition from a transcriptionally active to an inactive state and, once established, act redundantly to maintain transcriptional silencing. In this review, we survey the unique epigenetic features that characterize the inactive X chromosome, describe the mechanisms by which these marks are established and maintained, and discuss how each contributes to silencing the inactive X chromosome.
Cohen
Hannah R
HR
Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California 94143, USA.
Royce-Tolland
Morgan E
ME
Worringer
Kathleen A
KA
Panning
Barbara
B
D000818:Animals; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004261:DNA Replication; D004303:Dosage Compensation, Genetic; D005260:Female; D006657:Histones / Q000378:metabolism; D006801:Humans; D008297:Male; D008745:Methylation; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000502:physiology; D014960:X Chromosome / Q000235:genetics* / Q000378:metabolism*
D002843:Chromatin; D006657:Histones; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; C077885:XIST non-coding RNA; D004247:DNA