The fertilization layer mediated block to polyspermy in Xenopus laevis: isolation of the cortical granule lectin ligand.
The fertilization layer of Xenopus laevis eggs is formed by the cortical granule lectin binding to its ligand. The binding requires Ca2+, is specific for galactose, and functionally establishes a block to polyspermy at fertilization. We have designed a new enzyme-linked lectin assay for the cortical granule lectin (CGL) ligand which can detect the presence of the CGL ligand at a sensitivity of 1-2 ng/ml. This assay is specifically inhibited with galactose, 50% inhibition at 9.9 mM, and produces a linear response between 2 and 20 ng of jelly adsorbed to the microtiter plate. Using this assay, the CGL ligand was purified through gel filtration, anion-exchange, and CGL affinity chromatography. Hydrolysis of the purified CGL ligand with a series of exoglycosidases showed that a terminal alpha-galactose is the ligand structure required for recognition by CGL.
Quill
T A
TA
Section of Molecular and Cellular Biology, University of California, Davis 95616, USA.
Hedrick
J L
JL
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004527:Egg Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005306:Fertilization; D008297:Male; D009865:Oocytes / Q000502:physiology*; D012680:Sensitivity and Specificity; D013084:Sperm-Ovum Interactions; D014982:Xenopus laevis
D000596:Amino Acids; D004527:Egg Proteins; D002118:Calcium