Atlas of Wnt and R-Spondin Gene Expression in the Developing Male Mouse Lower Urogenital Tract

Prostate development is influenced by beta-catenin signaling, but it is unclear which beta-catenin activators are involved, where they are synthesized, and whether their mRNA abundance is influenced by androgens. We identified WNT/beta-catenin-responsive beta-galactosidase activity in the lower urogenital tract (LUT) of transgenic reporter mice, but beta-galactosidase activity differed among the four mouse strains we examined. We used in situ hybridization to compare patterns of Wnts, r-spondins (Rspos, co-activators of beta-catenin signaling), beta-catenin-responsive mRNAs, and an androgen receptor-responsive mRNA in wild type fetal male, fetal female, and neonatal male LUT. Most Wnt and Rspo mRNAs were present in LUT during prostate development. Sexually dimorphic expression patterns were observed for WNT/beta-catenin-responsive genes, and for Wnt2b, Wnt4, Wnt7a, Wnt9b, Wnt10b, Wnt11, Wnt16, and Rspo3 mRNAs. These results reveal sexual differences in WNT/beta-catenin signaling in fetal LUT, supporting the idea that this pathway may be directly or indirectly responsive to androgens during prostate ductal development. Developmental Dynamics 240: 2548-2560, 2011. (C) 2011 Wiley Periodicals, Inc.