Chromatin modifications on the inactive X chromosome.

Progress in molecular and subcellular biology

PubMedID: 15881892

Cohen HR, Royce-Tolland ME, Worringer KA, Panning B. Chromatin modifications on the inactive X chromosome. Prog Mol Subcell Biol. 2005;.
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.