XENOPUS ZIC3, A PRIMARY REGULATOR BOTH IN NEURAL AND NEURAL CREST DEVELOPMENT

Xenopus Zic3 is a Xenopus homologue of mouse Zic and Drosophila pair-r ule gene, odd-paired. We show here that Zic3 has significant roles bot h in neural and neural crest development in Xenopus embryo. Expression of Zic3 is first detected in prospective neural plate region at gastr ulation. Onset of the expression was earlier than most proneural genes and followed chordin expression, The expression was induced by blocka de of BMP4 signal. Overexpression of Zic3 resulted in hyperplastic neu ral and neural crest derived tissue. In animal cap explant, the overex pression of Zic3 induced expression of all the proneural genes and neu ral crest marker genes. These findings suggest that Zic3 can determine the ectodermal cell fate and promote the earliest step of neural and neural crest development.