Figure 2. SPEN localizes to the X chromosome immediately upon Xist upregulation and throughout the stages of XCI, but is dispensable for maintenance of X-linked gene silencing.
a, Images from combined HaloTag labeling of SPEN (green) and FISH for Xist RNA (red) in mESCs during a time course of Xist induction, and b, in NPCs. c, Schematic of the SPEN-degron experiment in NPCs. d, Cumulative distribution of transcript allelic ratios across the X chromosome (n=387 genes) after SPEN depletion in NPCs. e, Cumulative distribution and f, violin plot representation of transcript allelic ratio of escapees after SPEN depletion in NPCs (two-sided Wilcoxon signed-rank test, n=65, horizontal lines denote the median, box limits correspond to upper and lower quartiles). d, e and f, show averages of two independent NPC clones. a, b, These experiments were repeated at least twice with similar results.