IMMUNOCYTOCHEMICAL STUDY OF THE DISTRIBUTION OF A GANGLIOSIDE IN SEA-URCHIN EGGS

An antibody against M5 ganglioside (NeuGca2-6Glcβl-lCer), the dominant ganglioside in the eggs of the sea urchin, Anthocidaris crassispina, was purified by affinity chromatog raphy from rabbit antiserum against crude ganglioside of the eggs. The specificity of the antibody was verified by enzyme-linked immunosorbent assay and TLC iminunostaining. M5 ganglioside was also the major one in the eggs of another sea urchin, Hemicentrotus pulcherrimus, as judged from TLC analyses including immunostalning. Cryostat-sections of H. puicherrimus eggs were examined to determine the distribution of M5 ganglioside by indirect immunofluorescence microscopy with the antibody. Before fertilization, the egg cortex was highly stained, while the other part of cytoplasm was uniformly but much more weakly stained. Mter fertilization, the staining rapidly decreased In the cortex and was restricted to a very thin peripheral layer and to cytoplasmic patches. The Immunore activity was also observed in the esophagus and the somatic cells of the testis, but the spermatozoa were never stained with the antibody. © 1990 Copyright, 1990 by the Journal of Biochemistry.