Canonical Wnt/ß-catenin activity and differential epigenetic marks direct sexually dimorphic regulation of Irx3 and Irx5 in developing mouse gonads

Irx3 and Irx5 are important for oocyte and follicle survival within the developing ovary, but their regulation had not been elucidated. Methods: XX and XY supporting cells of the gonad were FACS-purified at E13.5, and submitted to ChIP-seq for H3K27me3 and H3 as a means to normalize across cell populations. Results: We identified TCF/LEF-binding sequences within two distal enhancers of the IrxB locus that promote ß-catenin responsive ovary expression. Meanwhile, Irx3 and Irx5 transcription is suppressed within the developing testis by the presence of H3K27me3 on these same sites. Overall design: ChIP-seq for H3 and H3K27me3 was performed in duplicate on FACS-sorted XX and XY gonadal supporting cells from E13.5 mouse embryonic gonads.