Figure 1. Xi gene silencing can be initiated, but not maintained, without Xist Repeat B.
See also Figures S1 and S2.
(A) Boxplots of allele-specific RNA-seq timecourse showing abortive Xi gene silencing in ΔRepB versus WT Xist differentiating female ESCs. Two-tailed student t-test, p values for pairwise comparison as shown.
(B) Zoom-in of allele-specific RNA-seq tracks showing reads from individual X-linked genes.
(C) Allele-specific RT-qPCR showing relative expression from each allele for several X-linked genes in WT Xist and ΔRepB differentiating female ESCs. Error bars show standard deviation between 3 biological replicates. Two-tailed student t-test, asterisks indicate p < 0.05.
(D) Atrx and Mecp2 nascent RNA FISH combined with Xist RNA FISH in WT Xist and ΔRepB differentiating female ESCs. Diffuse Xist cloud morphology caused by disruption of Repeat B/Polycomb was previously described (Colognori et al., 2019). Arrowheads mark positions of Xist cloud.
(E) Quantification of (D). Note that no Xist clouds are present at day 0 to indicate Xmus, but expression is inferred by the presence of two pinpoint signals. n > 100 per time point.