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LOCALIZATION OF ARYLSULFATASE-A IN MOUSE TESTICULAR GERM CELLS AND EPIDIDYMAL SPERM.
Weerachatyanukul, Wattana1,2, Sobhon, Prasert 2, Tanphaichitr, Nongnuj 1,3, 1 2 3
ABSTRACT- We have previously shown that arylsulfatase-A (AS-A) exists on pig and mouse sperm surface using affinity purified anti-AS-A IgG. In this report, we used the same antibody to localize AS-A in mouse developing germ cells and epididymal sperm by means of indirect immunofluorescence (IIF) and immunoelectron microscopy. During spermatogenesis, AS-A was initially detectable within the proacrosomal granule of pachytene spermatocytes. In differentiated spermatids and testicular sperm, the staining of anti-ASA antibody was predominant in the acrosomal granule and fully extended acrosome. Ultrastructurally, the localization of AS-A was observed in the developing acrosomal granule of the Golgi phase spermatid, and was restricted to the peripheral region of the extended acrosomal granule in the cap phase spermatid, or to the dorsal region of the acrosome in testicular sperm. However, AS-A was not present on the plasma membrane of any testicular germ cells. Using live sperm taken from different parts of the epididymis, we localized AS-A by IIF to the postacrosomal region of caput epididymal sperm, and to both the postacrosome and the convex ridge over the acrosome in cauda epididymal sperm. These results suggest that AS-A secreted into the epididymal lumen may be adsorbed onto the surface of sperm during their migration through this organ, the phenomenon, which appears to be similar to that described for beta-galactosidase, existing on the sperm surface. Localization of AS-A, using its antibody and enzymatic reaction, of the epididymal sections at the electron microscopy level is ongoing in our laboratory to verify this postulation. This work was supported by CIHR grant MT 10366, the Rockefeller Foundation and National Science and Technology Development Agency of Thailand (NSTDA).
KEY WORDS: arylsulfatase-A, spermatogenesis, epididymis