SIAR Is Specific to Pluripotent Cells In Vitro and In Vivo

<div><p>(A) Percent SD signals observed by FISH for the <i>Xic</i> in cell types that are poised for X-inactivation (ES and ICM), and in trophectoderm (TE) cells and MEFs, which have completed X-inactivation. </p> <p>(B) Allele-specific FISH for the <i>Xic</i> (red) in Δ <i>Xist</i>/+ ICM cells. An <i>Xist</i> probe (green) identifies the wild-type allele; white arrowhead indicates the Δ <i>Xist</i> allele. In 12 of 15 SD cells ( <i>p</i> = 0.02), the Δ <i>Xist</i> allele exhibited the doublet signal. </p> <p>(C) Percent SD signals observed for an autosomal biallelic locus <i>(Hba1)</i> and two X chromosomal loci <i>(Mecp2</i> and the <i>Xic)</i> in MEFs fixed with PFA (dark gray) or MeOH (light gray). Average data from two experiments ( <i>n</i> ≥ 150) are presented; error bars indicate one standard deviation. See <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040159#sg004" target="_blank">Figure S4</a>B for complete scoring of SS, SD, and DD signals. </p>