A MONOCLONAL-ANTIBODY AGAINST NEURAL CREST-STAGE XENOPUS-LAEVIS LECTIN PERTURBS CRANIOFACIAL DEVELOPMENT OF XENOPUS

A monoclonal antibody that we have produced against the neural-crest-s tage galactoside-binding lectin of Xenopus laevis has has been used to confront neural crest cells in Xenopus embryos in vivo. Confronted ta dpoles have been raised to stage 47 (premetamorphosis) and examined fo r jaw defects in whole mounts and tissue sections. Antibody treatment correlates with no or grossly defective lower jaw development in 19% o f tadpoles. An increase in protrusion of the lower jaw and a decrease in the number of chondrocytes in the head is also noted. Further bioch emical studies uf the lectin reveal that it is an aggregate. Agglutina ting activity resides in a doublet protein that binds the monoclonal a ntibody. The results therefore suggest that interfering with the porti on of the lectin complex that has the agglutinating activity can have significant effects on craniofacial development.