Cross-linking of membrane glycoconjugates is not a sufficient condition for neural induction by concanavalin A.
Tetravalent native concanavalin A (Con A) has a neural inducing effect on amphibian presumptive ectoderm. The divalent dimeric form of this lectin, succinylated Con A (Succ-Con A), is devoid of neuralizing action on this target tissue in Pleurodeles waltlii. These results suggested that cross-linking of Con A receptors on the cell membrane (which is not provoked by the divalent lectin) might be required for neural induction. To test this possibility, Succ-Con A binding sites were experimentally cross-linked after binding of Succ-Con A to the target cell surface, using anti-Con A antibodies. The combination of these two agents mimics the cross-linking of Con A. The results showed that cross-linking alone, either by treatment with Succ-Con A and anti-Con A antibodies, or with the lectins WGA and PHA, which also cross-link cell surface binding sites, was not able to induce neuralization. This suggested that the inductive action of Con A cannot be explained in terms of receptor cross-linking.
Gualandris
L
L
UA-CNRS no. 675, Université Paul Sabatier, Toulouse, France.
Duprat
A M
AM
Rougé
P
P
D000818:Animals; D000906:Antibodies / Q000008:administration & dosage / Q000276:immunology; D002454:Cell Differentiation / Q000187:drug effects*; D002462:Cell Membrane / Q000187:drug effects / Q000648:ultrastructure; D003208:Concanavalin A / Q000031:analogs & derivatives / Q000276:immunology / Q000494:pharmacology*; D003429:Cross Reactions; D004475:Ectoderm / Q000166:cytology / Q000187:drug effects; D006001:Glycoconjugates / Q000378:metabolism*; D009417:Nerve Tissue / Q000187:drug effects / Q000196:embryology / Q000254:growth & development*; D010835:Phytohemagglutinins / Q000494:pharmacology; D010999:Pleurodeles / Q000196:embryology*; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000187:drug effects; D012455:Salamandridae / Q000196:embryology*; D014909:Wheat Germ Agglutinins / Q000494:pharmacology
D000906:Antibodies; D006001:Glycoconjugates; D010835:Phytohemagglutinins; D011956:Receptors, Cell Surface; D014909:Wheat Germ Agglutinins; D003208:Concanavalin A; C019558:succinylconcanavalin A