Conclusions

Over a period spanning some 15 yr, we have exploited microinjected oocytes and embryos of Xenopus laevis to clone and characterize the human genes encoding AChE and BuChE and their protein products. Subsequently, we tapped into the enormous versatility of Xenopus to continue into the realm of tissue-specific processing and gene function studies. These studies not only revealed crucial elements in the “ChE story” themselves but provided the experimental background for complementary studies in primary cell cultures and transgenic mice. The observation that the morphogenetic implications of AChE overexpression in Xenopus NMJs correspond to those observed in NMJs of transgenic mice overexpressing AChE in CNS neurons (Andres et al., in preparation) supports the growing use of microinjected Xenopus embryos as a model for vertebrate development, and synaptogenesis in particular.