Expression of basigin in reproductive tissues of estrogen receptor-α or -β null mice

Basigin plays important roles in both male and female reproduction because basigin (Bsg) null male and female mice are infertile. The aim of the present study was to determine whether basigin expression in reproductive organs requires estrogen receptor-alpha (ESR1, ER alpha) or -beta (ESR2, ER beta). Expression of basigin protein in the testis, ovary, and male and female reproductive tracts was studied in adult wild-type (WT), Esr1-null (alpha ERKO), and Esr2-null (beta ERKO) mice by immunohistochemistry and immunoblotting. Basigin mRNA levels in ovary and uterus were examined by quantitative RT-PCR. In females, basigin protein expression was observed mainly in granulosa and interstitial cells of the ovary and epithelial cells of the proximal oviduct in all genotypes. Basigin protein was also expressed in the uterine epithelium at proestrus and estrus in WT and beta ERKO mice but not in alpha ERKO mice. However, a higher level of basigin mRNA was observed in uteri of alpha ERKO mice compared with WT and beta ERKO mice. In males, basigin was expressed in Leydig cells and all germ cells except spermatogonia in all genotypes. Basigin was present in epithelial cells lining the efferent ductules in WT and beta ERKO mice, but expression was greatly reduced in alpha ERKO mice. In epididymal ducts, basigin expression was observed in epithelial cells in the caput and cauda in all genotypes. These data suggest that expression of basigin protein requires ESR1, but not ESR2, in the uterus and efferent ductules, but is independent of estrogen receptor in the ovary, oviduct, testis, and epididymis. Reproduction (2010) 139 1057-1066