Lectin binding in early mouse embryos.

Lectin binding in early mouse embryos was used to explore possible changes in cell surface properties during early development. Embryos at different stages of development were stained with fluorescein-coupled Concanavalin A (FITC-Con A) or wheat germ agglutinin (FITC-WGA). In zygote to 8-cell embryos, fixed with paraformaldehyde before staining or stained at 4 degrees C before fixation, the fluorescein-coupled lectins gave a continuous ring-like labelling of cell surfaces. When unfixed embryos stained at 4 degrees C with low concentrations of FITC-Con A (10--20 microgram/ml) were incubated at 37 degrees C they showed a continuous surface labelling at zygote stage but a patch-like aggregation of Con A-binding sites in 2-cell stage and older embryos. Use of higher lectin concentrations ( greater than 100 microgram/ml) did not result in patch formation at 37 degrees C. FITC-WGA gave a spotty but unaggregated labelling pattern also at 37 degrees C. The results show that in the early stages of mouse embryogenesis developmentally associated changes occur in the binding behaviour of Con A but not of WGA.