Isolation and identification of sperm maturation proteins (ER-, CK-19, AQP-1, and SLPI) in epididymis of bull (Bos taurus)Author(s): Sunita Awate, S.G.Ramachandra, S.Nandi, V.Girish Kumar, U.S.Pavana Shree
Epididymal spermmaturation is considered as an integral part of the process that permits mammalian gamete fusion and formation of the zygote. The present studies aimed at the identification of sperm maturation proteins namely, ER-á, CK-19, AQP-1, and SLPI in the different region (cauda, corpus, caput) of the normal and castrated bull epididymis by employing RT-PCR and western blot analysis. The study also aimed at understanding the intrinsic role of androgens in regulation of epididymal functions. The study revealed the presence of ER in all the three regions of the epididymis. However, castration caused a significant decrease in expression of ER-á in caput region and complete down-regulation on corpus and cauda region of epididymis. The expression of CK-19 was found to be more or less equally expressed in all the three regions of the normal bull epididymis. AQP-1 expression was observed only in the caput region of normal bull epididymis and there was complete absence of its expression in castration bull epididymis. Likewise, SLPI expression was also observed in the regions of normal bull epididymis. However, it was completely downregulated upon castration. Thus, the presence of ER-á, CK-19,AQP-1 and SLPI in the epididymis of the bull suggests their functional role in sperm maturation. Further, the presence of ER-á and CK-19 only in a particular region and complete absence ofAQP-1 and SLPI in all the three regions of the epididymis of the castrated bull was suggestive of dependence of epididymal function on androgens. Identification of specific markers for these proteins may pave way for diagnosis and treatment of infertility in domestic species as well as potential targets in the design of specific contraceptive medicines.