RNA-seq in TX1072 XO mESCs during differentiation

As the master regulator of X-chromosome inactivation (XCI), the Xist RNA is expressed nearly ubiquitously in female mice. Xist is only absent in the germ line and at the pluripotent state. Xist is generally assumed to be expressed “by default” in females, while being actively repressed in the few tissues where it is silent. Whether activating mechanisms also contribute remained largely unknown. Through a pooled CRISPR screen we identify the GATA family of transcription factors as potent direct activators of Xist. We describe a GATA-responsive regulatory element (RE79), located ~100 kb upstream of the Xist promoter. In cell lines derived from the two extraembryonic lineages, XEN and TS cells, where imprinted Xist expression is maintained, RE79 is bound by different sets of GATA factors expressed in those tissues. Here we use RNA-seq on differentiating XO mouse embryonic stem cells as a reference for gene expression during early differentiation. Overall design: RNA-seq was performed in the TX1072 XO cell line. The data was collected in replicates from cells in 2i+LIF medium (day 0), as well at days 1-4 of differentiation (via 2i+LIF-withdrawal).