Abstract
BackgroundSpermatogenesis and fertilization are highly unique processes. Discovery and characterization of germ cell-specific genes are important for the understanding of these reproductive processes. We investigated eight proteins encoded by novel spermatogenic cell-specific genes previously identified from the mouse round spermatid UniGene library.MethodsPolyclonal antibodies were generated against the novel proteins and western blot analysis was performed with various protein samples. Germ cell specificity was investigated using testes from germ cell-less mutant mice. Developmental expression pattern was examined in testicular germ cells, testicular sperm and mature sperm. Subcellular localization was assessed by cell surface biotin labeling and trypsinization. Protein localization and properties in sperm were investigated by separation of head and tail fractions, and extractabilities by a non-ionic detergent and urea.ResultsThe authenticity of the eight novel proteins and their specificity to spermatogenic cells were confirmed. In examining the developmental expression patterns, we found the presence of four proteins only in testicular germ cells, a single protein in testicular germ cells and testicular sperm, and three proteins in the testicular stages and mature sperm from the epididymis. Further analysis of the three proteins present in sperm disclosed that one is located at the surface of the acrosomal region and the other two are associated with cytoskeletal structures in the sperm flagellum. We name the genes for these sperm proteins Shsp1 (Sperm head surface protein 1), Sfap1 (Sperm flagellum associated protein 1) and Sfap2 (Sperm flagellum associated protein 2).ConclusionWe analyzed eight novel germ cell-specific proteins, providing new and inclusive information about their developmental and cellular characteristics. Our findings will facilitate future investigation into the biological roles of these novel proteins in spermatogenesis and sperm functions.
Highlights
Spermatogenesis and fertilization are highly unique processes
Generation of antibodies and expression pattern of novel proteins Of 28 novel testis-specific genes investigated at the transcript level in our previous study [1], eight genes were analyzed at the protein level in this study (Fig. 1)
It should be noted that expressed sequence tags (ESTs) for some (Mm.87328, Mm.386907, Mm.157049 and Mm.57415) of the eight genes are found in non-testicular tissues in the current UniGene database
Summary
Discovery and characterization of germ cell-specific genes are important for the understanding of these reproductive processes. Male germ cell development involves successive mitotic (spermatogonia), meiotic (spermatocyte) and postmeiotic phases (spermatids). Spermatogonial stem cells, located around the outer region next to the basal lamina surrounding the seminiferous tubules in the testis, divide mitotically to produce primary spermatocytes. These cells continue through the first meiotic division to become haploid secondary spermatocytes. Secondary spermatocytes rapidly enter the second meiotic division to produce spermatids. These haploid spermatids are remodeled into sperm by spermiogenesis. The acrosome derived from the Golgi apparatus envelopes the anterior portion of the condensed nucleus
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
