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Establishment of X chromosome inactivation and epigenomic features of the inactive X depend on cellular contexts
Author(s) -
Vallot Céline,
Ouimette JeanFrançois,
Rougeulle Claire
Publication year - 2016
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.201600121
Subject(s) - epigenetics , x inactivation , epigenomics , biology , context (archaeology) , genetics , epigenesis , phenotype , mechanism (biology) , x chromosome , evolutionary biology , dna methylation , microbiology and biotechnology , gene , gene expression , physics , paleontology , quantum mechanics
X chromosome inactivation (XCI) is an essential epigenetic process that ensures X‐linked gene dosage equilibrium between sexes in mammals. XCI is dynamically regulated during development in a manner that is intimately linked to differentiation. Numerous studies, which we review here, have explored the dynamics of X inactivation and reactivation in the context of development, differentiation and diseases, and the phenotypic and molecular link between the inactive status, and the cellular context. Here, we also assess whether XCI is a uniform mechanism in mammals by analyzing epigenetic signatures of the inactive X (Xi) in different species and cellular contexts. It appears that the timing of XCI and the epigenetic signature of the inactive X greatly vary between species. Surprisingly, even within a given species, various Xi configurations are found across cellular states. We discuss possible mechanisms underlying these variations, and how they might influence the fate of the Xi.