Meta-analysis of the heterogeneity of X chromosome inactivation in XXXX pluripotent stem cells.

@entity19 @entity1 @entity6630 @entity23675
In mammals, X chromosome inactivation (XCI) is a process in which one of the two X chromosomes is silenced, following @entity6630 expression. @entity19 female pluripotent stem cells do not express @entity23675 , and harbor two active X chromosomes. However, analysis of XCI in @entity1 embryonic stem cells (hESCs), mainly based on @entity6630 expression, was not conclusive. Here, we studied XCI in hESCs by meta-analysis of the expression of the entire set of genes on the X chromosome in 21 female hESC lines. Thus, we could divide the ES cell lines into three categories: lines with no XCI, lines with full XCI, and lines with partial XCI. The partial inactivation of the X chromosome always involved the middle of the chromosome, surrounding the @entity6630 transcription site. The status of XCI in some of the cell lines was validated by either allelic-specific expression or DNA methylation analysis. Interestingly, analysis of 10 female @entity1 -induced pluripotent stem cell (hiPSC) lines demonstrated similar heterogeneity in the inactivation of X chromosome and could also be classified into the same three categories detected in hESCs. Thus, we could show that in some hiPSC lines, the X chromosome was activated on reprogramming. Based on our analysis, we propose a model of the dynamics of XCI in pluripotent stem cells.
