Deletion of Rspo1 or Rspo3 in the mesenchyme does not affect Wolffian duct maintenance or morphogenesis.

Secreted proteins, R-Spondin 1 (RSPO1) and R-Spondin 3 (RSPO3), potentiate WNT/β-catenin signaling that play critical roles in reproductive organ development. However, the functional significance of RSPO1 and RSPO3 in Wolffian duct development remains undefined. In this report, we demonstrated their specific expression in the Wolffian duct mesenchyme during sexual differentiation. We generated individual conditional knockouts using Osr2-Cre that deleted Rspo1 or Rspo3 in the Wolffian duct mesenchyme. Wolffian duct maintenance and morphogenesis was unaffected in either Rspo1 or Rspo3 conditional knockout mice. Our results indicate that mesenchymal Rspo1 or Rspo3 is dispensable for Wolffian duct development in mice.