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The formation of brain tissue owes its specificity to multiple steps involving cell interactions during various stages of ontogenesis. Guided neuron migration, synaptogenesis and myelination constitute three essential steps in brain organization, where glycobiological recognition or adhesion systems play a fundamental role. The key molecules in these phenomena were postulated to belong to the family of cell adhesion molecules (CAMs; Crossin et al., 1986; Edelman, 1985 and 1986; Grumet et al., 1985; Hoffmann et al., 1986; Hoffmann and Edelman, 1987; Rieger et al., 1986; Salzer and Colman, 1989) acting by homophilic interactions. More recently two different mannose-binding endogenous lectins of similar specificity (Zanetta et al., 1985a and 1987a) seem to play important roles in relation with their endogenous glycoprotein ligands (Kuchler et al., 1988, 1989a,b and c; 1990a,b and c; Lehmann et al., 1990). It is worthy of mention that some of these glycoprotein ligands are members of the family of cell adhesion molecules (Kuchler et al., 1988, 1989a and b; 1990a and b) and share specific glycans binding to some onco-fetal antibodies. Thus, heterophilic interactions involving glycobiological system deserve attention. This paper summarizes the major observations concerned with the function in the brain of the two endogenous mannose-binding lectins, called CSL and R1 (Zanetta et al., 1985a and 1987a) and of their endogenous ligands. |
