Xist upstream deletion impairs topological contacts of Xist locus and affects Xist coating/expression and autosomal gene expression [ChIP-Seq]

In this study, we have investigated the role of Xist upstream region located near the Xist-TAD boundary in maintenance of imprinted X-chromosome inactivation in extraembryonic endoderm stem cells (XEN). We found that deletion of Xist upstream region(~6Kb) leads to the alterations of Xist intra-TAD contacts and upregulate Xist expression. Moreover, it impaired the interactions of the Xist locus across X-chromosomes and autosomes. Moreover, Xist upstream deletion resulted dispersal of Xist coating and loss of accumulation of diffrent repressive chromatin marks on the inactive-X. Surprisingly there was no effect on inactive-X gene silencing, however, it affeted the autosomal gene expression.