Membrane β-catenin and adherens junctions in early gonadal patterning.

Background: Mechanisms involved in early patterning of the mammalian gonad as it develops from a bipotential state into a testis or an ovary are as yet not well understood. Sex-specific vascularization is essential in this process, but more specific mechanisms required to, for example, establish interstitial vs. cord compartments in the testis or ovigerous cords in the ovary have not been reported. Adherens junctions (AJs) are known for their roles in morphogenesis; we, therefore, examined expression of AJ components including β-catenin, p120 catenin, and cadherins for possible involvement in sex-specific patterning of the gonad.

Results: We show that, at the time of early gonadal sex differentiation, membrane-associated β-catenin and p120 catenin colocalize with cell-specific cadherins in both sex-nonspecific and sex-specific patterns. These expression patterns are consistent with an influence of AJs in overall patterning of the testis vs. ovary through known AJ mechanisms of cell-cell adhesion, cell sorting, and boundary formation.

Conclusions: Together these complex and dynamic patterns of AJ component expression precisely mirror patterning of tissues during gonadogenesis and raise the possibility that AJs are essential effectors of patterning within the developing testis and ovary.