Immunolocalization of retinoic acid receptor-alpha, -beta, and -gamma, in bovine and canine sperm

Retinoic acid is an important regulator of cellular proliferation and differentiation. The action of retinoic acid is mediated by retinoic acid receptors (RARs) and the retinoid X receptors. The objective was to elucidate the protein localization and expression of RARα, RARβ, and RARγ in bull and dog sperm. Bull and dog sperm were subjected to an immunostaining procedure to determine presence of RARα, RARβ, and RARγ. We concluded that all three receptors were present in different regions of bull and dog sperm at varying levels. Protein expression in bull and dog sperm lysates was investigated using protein dot-blot analyses. The protein levels of RARα and RARγ were higher than the protein level of RARβ in bull and dog sperm. Protein sequences of RARα, RARβ, and RARγ for bull and dog were 98%, 89%, and 98%, respectively, on similarity alignment. In conclusion, the presence of RARα, RARβ, and RARγ receptors supported their role in sperm structure and function.