Cloning and expression of a Xenopus laevis oocyte lectin and characterization of its mRNA levels during early development

^ o whom correspondence should be addressed cDNA clones encoding a soluble, calcium-dependent, meli-biose-binding lectin from Xenopus laevis oocytes have been isolated, characterized, and expressed in bacteria. This lec-tin has been shown by others to be localized in oocyte cor-tical granules where it ultimately is released and partici-pates in the formation of the fertilization envelope. A lectin with similar specificity has been purified by others from blastula and immunolocalized to specific locations in devel-oping embryos, which suggests it may also function after fertilization in regulating cell adhesion and migration. We have used melibiose affinity chromatography to isolate the oocyte lectin (monomer molecular masses of about 45 and 43 kDa) and shown that after exhaustive treatment with JV-g]ycanase, only one major protein band at 35 kDa wa