Runumi Baro

Keywords X-chromosome inactivation m6A -RNA methylation Xist embryonic stem cells ESC epiblast stem cells EpiSC trophoblast stem cells TSC extraembryonic endoderm stem cells XEN Introduction In the course of evolution, the Y chromosome underwent massive degradation through gene-loss events (Bachtrog, 2013; Graves, 2016; Lahn and Page, 1999). This rendered male-specific monoallelic expression of X-linked genes in contrast to biallelic expression from the autosomes.

Abstract In therian mammals, inactivation of one of the X-chromosomes in female cells (XX) balances the dosage of X-linked gene expression between the sexes, resulting in monoallelic expression of X-linked genes in females similar to males (XY). Therefore, it creates a dosage imbalance for X-linked genes with respect to the biallelically expressing autosomal genes (AA).

Abstract The topological organization of the genome plays an important role in regulating gene expression. However, the connection between the two remains poorly understood. X chromosome inactivation is a unique model system to explore the interlink between topologically associated domains (TADs) and gene expression. TADs are largely lost upon X inactivation, and the inactive X gets bipartitely reorganized into two large mega domains.