BINDING OF LECTINS TO NOVEL MIGRATION PROMOTERS ON CARDIAC MESENCHYMAL CELLS IN THE CHICK

Chicken serum promotes migration of cardiac mesenchymal cells of chick embryos in vitro. In the present study, migration promotion of unknow n migration promoters in chicken serum was examined by using lectins. Cardiac mesenchymal cells of the conotruncal and atrioventricular cush ions were cultured on collagen type-I gel with medium including chicke n serum. A concentration (100 mu g/ml) of Concanavalin A (Con A), pean ut agglutinin (PNA), pisum sativum agglutinin (PSA), soybean agglutini n (SBA) or wheat germ agglutinin (WGA) was added to the medium. Con A, PSA, and WGA inhibited migration, while PNA and SBA did not affect mi gration of cardiac mesenchymal cells. WGA inhibited migration in a con centration dependent manner. Preincubation of WGA with specific bindin g monosaccharides (alpha-D-N-acetylglucosamine and alpha-D-N-acetylneu raminic acid) clearly reduced the inhibition ability of WGA, while pre incubation of Con A and PSA with alpha-D-mannose and alpha-D-glucose d id not. On the other hand, Con A-binding proteins, eluted from a Con A affinity column with the buffer including alpha-D-mannose and alpha-D -glucose, promoted migration of cardiac mesenchymal cells, as did WGA- binding proteins. These proteins promoted migration in a concentration dependent manner. Western blotting showed that PSA bound the subunits of collagen type-I, but ConA and WGA did not. In migration inhibition assays by monosaccharides, only N-acetylneuraminic acid inhibited mig ration of cardiac mesenchymal cells. These results suggested that chic ken serum contains novel migration promoters for chick cardiac mesench ymal cells. The promoters are proposed to have the terminal N-acetylgl ucosamine, N-acetylneuraminic acid, and glucose and/or mannose residue s.