title: 5-Azadeoxycytidine distinguishes between active and inactive X chromosome condensation.
abstract: Treatment with 5-azadeoxycytidine (5-aza-dC) causes dramatic inhibition of mitotic condensation in the inactive X chromosome, without affecting the active X chromosome and autosomes. The undercondensed chromatin structure is most prominent in the late-replicating regions of the inactive X chromosome, whereas specific earlier-replicating segments on the inactive X probably associated with large blocks of genes that escape inactivation remain normally condensed. This segmentation of inactive X chromosomes has been evolutionarily conserved and is unique to mammals. It suggests temporal or mechanistic separation in condensation of inactive X chromatin. Condensation of chromatin structure is a novel and general feature of inactive X chromosomes that may be involved, directly or indirectly, in the maintenance and stabilization of X inactivation.
authors.affiliation: Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06510-8005.
authors.forename: T
authors.initials: T
authors.lastname: Haaf
authors.forename: P
authors.initials: P
authors.lastname: Werner
authors.forename: M
authors.initials: M
authors.lastname: Schmid
mesh_terms: D000818:Animals; D001374:Azacitidine / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D002871:Chromosome Banding; D005786:Gene Expression Regulation / Q000187:drug effects; D006570:Heterochromatin / Q000648:ultrastructure; D006801:Humans; D008745:Methylation; D008938:Mitosis; D014960:X Chromosome / Q000187:drug effects / Q000648:ultrastructure*
chemical_list: D006570:Heterochromatin; D001374:Azacitidine