Fig. 1.

Conditionally deleting Xist shortly after implantation (Meox2-Cre) and establishment of XCI does not affect overall female survival. (A) Schematic of the conditional Xist allele with region of deletion shown in blue. (B) Representative Xist RNA-FISH images of fibroblasts of control (Xist^fl/WT), heterozygous mutants (Xist^fl/WT; Meox2-Cre), and homozygous mutants (Xist^fl/fl; Meox2-Cre). At least 100 nuclei were counted per sample. Xist^fl/WT, n = 2 animals; Xist^fl/WT; Meox2-Cre, n = 6; Xist^fl/fl; Meox2-Cre, n = 2. Error bars denote mean ± SEM. (Scale bar, 5 μm.) (C) Kaplan–Meier survival curve for mouse crosses as indicated. (D) Xist RT-qPCR for panel of tissues from Xist homozygous mutants. The average expression of at least four mutant animals per tissue type is indicated; normalization was to Xist expression in corresponding tissues from four to six control animals. (E) Representative Xist RNA-FISH for tissue sections from control and homozygous mutant animals. LKS⁺; Lineage⁻ cKit⁺ Sca1⁺ hematopoietic progenitors. (Scale bars: 50 μm; for LKS⁺ hematopoietic progenitors, 5 μm.)