ALTERATION OF MORPHOGENETIC CELL-INTERACTIONS BY 1-BETA-D-ARABINOFURANOSYLCYTOSINE IN BUFO-ARENARUM EMBRYO

Amphibian gastrulation was used as a model system to study the action of the nucleoside 1-beta-D-arabinofuranosylcytosine (Ara-C) on the ear ly events of amphibian morphogenesis. Ara-C inhibits both glycoprotein and glycolipid synthesis and interferes with DNA synthesis. Thus, it is useful to investigate the importance of the cell surface and the nu cleous during Bufo arenarum morphogenesis. Living embryos were incubat ed with Ara-C at blastula and gastrula stages. Treated-embryos undergo abnormal gastrulation, most of the embryos exogastrulate, although so me do not gastrulate at all. This antimetabolite did not interfere wit h neural induction, as partial exogastrulae developed a small neural t ube. We have proven that Area-C disturbs the typical intercellular org anization and inhibits the radial intercalation of the blastocoelic ro of. The mesodermal migration is the most affected morphogenetic proces s. The results described in this paper demonstrate that the timing of gastrulation movements strongly involves the participation of surface and extracellular molecules in cell recognition and cell interaction b ut does not involve a significant increase in cell division rate and c an also occur in the absence of the cell division.