Developmental changes of glycoconjugates in early mouse embryonic neuroepithlium, notochordal and surrounding mesenchymal interactions

ABSTRACT

During early neural tube formation, the notochord is essentialfor the induction of ectoderm and for the subsequent differentiation of theneuroepithelium forming diverse cell types in the neural tube. Due to thekey role of the glycoconjugates in many developmental events, the earlydistribution of these molecules in early notochordal interaction withadjacent tissues were studied. Material and Paraffin fixed 5m sections of days 10 to 14 of mouse embryo were processed for histochemical studies by using horseradish peroxidase labelled DBA, VVA-B4, WFA, UEA-1 and OFA lectins.These lectins have binding specificity for D-GalNac and a-fucose sidechains of the glycoconjugates. Histochemical analysis revealed that notochord and itsintermediate extracellular fluid show extensive reaction with the floor plateof neural tube on 10th day, using OFA. This reaction was absent in thenext day but a sever reaction was observed in the floor plate region. Theresults revealed a reaction in venteral portion of notochord with VVA-B4and it expanded in to gut tube. Furthermore, a WFA-reaction was observedin the notochord and some of adjacent mesenchymal cells, but UEA-1 and DBA, don't showed any reaction. The expression of the GalNac and also fucosilatedglycoconjugates is stage-dependent and thus probably geneticallyregulated. The timing and distribution of lectin reactions suggest that thesemolecules [GalNac and fucose] may play a role[s] in notochordalinteractions and subsequent formation of the adjacent tissues