Diversity of X-chromosome inactivation patterns during early mammalian development - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Access content directly
Conference Papers Year : 2009

Diversity of X-chromosome inactivation patterns during early mammalian development

Abstract

X-chromosome inactivation ensures dosage compensation for Xlinked gene products in mammals. In eutherians, X inactivation is controlled by the non-coding Xist transcript and is usually random, with either the paternal or maternal X being chosen for silencing. In marsupials, which have no Xist gene, X inactivation is subject to imprinting, with non-random inactivation of the paternal Xp chromosome in all cells. Despite showing random X inactivation in their somatic cells, rodents do in fact display imprinted X inactivation during early development and in extra-embryonic tissues. This early, imprinted form of X inactivation in rodents appears to be due to imprinted Xist expression. The pattern of Xist expression and X inactivation during the early development of other eutherians remains unclear. Indeed the degree to which X inactivation is conserved between mammals remains an open question. We have investigated this process during early rabbit embryogenesis and find that the kinetics and monoallelic regulation of X inactivation are very different between rabbits and mice. Our results suggest that an imprinted form of X inactivation may have evolved more than once during the course mammalian evolution, first in marsupials, through an unknown mechanism; and later in some eutherians, such as rodents, via an Xist imprint. This provides evidence for remarkable evolutionary diversity in the mechanisms underlying dosage compensation mechanisms between mammals.

Dates and versions

hal-02751161 , version 1 (03-06-2020)

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Cite

Ikuhiro Okamoto, Véronique Duranthon, Dominique Thepot Thépot, Nathalie N. Peynot, Jean Paul J. P. Renard, et al.. Diversity of X-chromosome inactivation patterns during early mammalian development. 68. Annual Meeting of the Society for Developmental Biology, Jul 2009, San Francisco, United States. ⟨10.1016/j.ydbio.2009.05.035⟩. ⟨hal-02751161⟩
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