UTX regulates mesoderm differentiation of embryonic stem cells independent of H3K27 demethylase activity

Abstract

To investigate the role of histone H3K27 demethylase UTX in embryonic stem (ES) cell differentiation, we have generatedUTXknockout (KO) and enzyme-dead knock-in male ES cells. Deletion of the X-chromosome-encodedUTXgene in male ES cells markedly decreases expression of the paralogousUTYgene encoded by Y chromosome, but has no effect on global H3K27me3 level,Hoxgene expression, or ES cell self-renewal. However,UTXKO cells show severe defects in mesoderm differentiation and induction ofBrachyury, a transcription factor essential for mesoderm development. Surprisingly, UTX regulates mesoderm differentiation andBrachyuryexpression independent of its enzymatic activity. UTY, which lacks detectable demethylase activity, compensates for the loss of UTX in regulatingBrachyuryexpression. UTX and UTY bind directly toBrachyurypromoter and are required for Wnt/β-catenin signaling-inducedBrachyuryexpression in ES cells. Interestingly, maleUTXKO embryos express normal levels ofUTYand survive until birth. In contrast, femaleUTXKO mice, which lack theUTYgene, show embryonic lethality before embryonic day 11.5. FemaleUTXKO embryos show severe defects in bothBrachyuryexpression and embryonic development of mesoderm-derived posterior notochord, cardiac, and hematopoietic tissues. These results indicate that UTX controls mesoderm differentiation andBrachyuryexpression independent of H3K27 demethylase activity, and suggest that UTX and UTY are functionally redundant in ES cell differentiation and early embryonic development.