Sperm-associated antigen 11A is expressed exclusively in the principal cells of the mouse caput epididymis in an androgen-dependent manner

Reproductive Biology and Endocrinology

Research

Dwi A Pujianto¹  Yurnadi H Midoen¹  Purnomo Soeharso¹  Puji Sari¹  Evelyn Loanda² 

[1] Department of Biology, Faculty of Medicine, University of Indonesia, Jl. Salemba Raya 6, 10430, Jakarta, Indonesia;Master Program for Biomedical Sciences, Faculty of Medicine, University of Indonesia, Jl. Salemba Raya 6, 10430, Jakarta, Indonesia;Department of Biochemistry, Faculty of Medicine, Atma Jaya Catholic University, Jl. Pluit Raya 2, 14440, Jakarta, Indonesia;

关键词: Spag11a;    Epididymis;    Androgen;    Secretory protein;    Principal cells;   

DOI  :  10.1186/1477-7827-11-59

 received in 2012-12-04, accepted in 2013-06-26,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundEpididymal sperm maturation occurs via interactions between sperm and proteins secreted by the epididymal epithelium. Although this is an important process, the genes that encode the involved proteins remain largely uncharacterized. Previous studies have demonstrated that the genes involved in sperm maturation are regulated by androgen. Spag11a is an epididymal gene that is influenced by androgen. However, little is known about the putative role of this gene in the sperm maturation process. The objective of this study was to characterize Spag11a in the mouse epididymis.MethodsIn silico analyses were performed to predict signal peptides and functional domains. Spag11a expression was measured by quantitative real-time RT-PCR. Western blots and immunocytochemistry were performed to determine protein expression.ResultsSPAG11A is a member of the beta defensin protein family and constitutes a secretory protein. Spag11a was expressed exclusively in the epididymis. Moreover, it exhibited region-specific expression in the caput, which is typical for genes that are involved in creating a suitable microenvironment for sperm maturation. Mouse Spag11a was regulated by androgen. A significant decrease of Spag11a expression was observed at third day following a gonadectomy (P < 0.001). Interestingly, testosterone replacement therapy was able to maintain the expression almost at the normal level, indicating a dependency on androgen. Besides androgen, testicular factors influenced Spag11a expression in a different way. This was revealed by efferent duct ligation in which Spag11a was transiently up-regulated at the third day following the ligation before returning to the normal level at day 5. Spag11a regional expression was also observed at protein level detected by western immunoblotting which revealed a clear band in the caput but not in other regions. The prediction that SPAG11A is a secretory protein was confirmed by immunocytochemical analyses indicating cell-specific expression mainly in the caput principal cells and detection of the protein in epididymal luminal fluid and spermatozoa.ConclusionsBased on the characteristics of Spag11a, it is likely that this gene has a specific role in epididymal sperm maturation. Further studies using functional assays are necessary to confirm this finding.

【 授权许可】

CC BY   
© Pujianto et al.; licensee BioMed Central Ltd. 2013