ABSTRACT
Amphibian gastrulation was used as a model system to study the action of the nucleoside 1-beta-D-arabinofuranosylcytosine (Ara-C) on the early 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 nucleous during Bufo arenarum morphogenesis. Living embryos were incubated with Ara-C at blastula and gastrula stages. Treated-embryos undergo abnormal gastrulation, most of the embryos exogastrulate, although some do not gastrulate at all. This antimetabolite did not interfere with neural induction, as partial exogastrulae developed a small neural tube. We have proven that Area-C disturbs the typical intercellular organization and inhibits the radial intercalation of the blastocoelic roof. The mesodermal migration is the most affected morphogenetic process. 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 but does not involve a significant increase in cell division rate and can also occur in the absence of the cell division.