title: Different flavors of X-chromosome inactivation in mammals.
abstract: Dosage compensation of X-linked gene products between the sexes in therians has culminated in the inactivation of one of the two X chromosomes in female cells. Over the years, the mouse has been the preferred animal model to study this X-chromosome inactivation (XCI) process in placental mammals (eutherians). Similar to the imprinted inactivation of the paternally inherited X chromosome (Xp) in marsupials (methatherians), the Xp is inactivated during early mouse development. In this eutherian model, cell derivatives of the primitive endoderm (PE) and trophectoderm (TE) will continue to display this imprinted form of XCI. Cells developing from the mouse epiblast will reactivate the Xp, and subsequently initiate XCI of either the Xp or the maternally inherited Xm, in a random manner. Examination of XCI in other eutherians and in metatherians, however, indicates clear differences in the form and timing of XCI. This review highlights and discusses imprinted and random XCI from such a comparative viewpoint.
authors.affiliation: Department of Reproduction and Development, Erasmus MC, University Medical Center, 3015GE Rotterdam, The Netherlands.
authors.forename: Cathérine
authors.initials: C
authors.lastname: Dupont
authors.forename: Joost
authors.initials: J
authors.lastname: Gribnau
mesh_terms: D000818:Animals; D005075:Biological Evolution; D050172:Genes, X-Linked; D008322:Mammals / Q000145:classification / Q000196:embryology / Q000235:genetics*; D051379:Mice; D023421:Models, Animal; D019849:Sex Determination Processes; D013045:Species Specificity; D049951:X Chromosome Inactivation