Osterixfunctions downstream of anti-Müllerian hormone signaling to regulate Müllerian duct regression

Significance In mammals, each embryo forms both male and female reproductive tract progenitor tissues. Anti-Müllerian hormone (AMH) secreted by fetal testes acts on mesenchyme cells adjacent to Müllerian duct (MD) epithelium, the progenitor tissue of female reproductive tract, to induce MD epithelial regression. While AMH and early AMH signaling components are elucidated, downstream gene networks directing this process are largely unknown. A global nonbiased approach using whole-transcriptome sequencing of fetal MD mesenchymal cells identified 82 factors as potential target genes of AMH includingOsterix (Osx ). Our findings provide in vivo evidence thatOsx is an AMH-induced gene that regulates MD regression. Identification ofOsx may provide key insights into gene-regulatory networks underlying MD regression, male sex differentiation, and mesenchyme–epithelial interactions.