Abstract
The paradigm of sexual differentiation holds that female embryos retain Müllerian ducts (the precursor to female reproductive tract) by default in the absence of anti-Müllerian hormone (AMH). However, whether Müllerian duct maintenance requires active signaling has remained unclear. Here, we discover that the deletion of mesenchymal Gata2 induces selective regression of the cranial Müllerian duct (future oviduct). This regression is not driven by ectopic AMH signaling, but rather by the loss of region-specific NRG1 signaling. In contrast, the caudal Müllerian duct (future uterus) is retained and displays disrupted epithelial differentiation upon Gata2 deletion in either the mesenchymal or epithelial compartments. Our findings reveal a region-specific, GATA2-dependent program that actively maintains the cranial Müllerian duct, reshaping our understanding of female reproductive tract development.