A novel member of the Xenopus Zic family, Zic5, mediates neural crest development

We characterized Xenopus Zic5 which belongs to a novel class of the Zic fam ily. Zic5 is more specifically expressed in the prospective neural crest th an other Zic genes. Overexpression of Zic5 in embryos led to ectopic expres sion of the early neural crest markers, Xsna and Xslu, with the loss of epi dermal marker expression. In Zic5-overexpressing animal cap explants, there was marked induction of neural crest markers, without mesodermal and anter ior neural markers. This was in contrast to other Xenopus Zic genes, which induce both anterior and the neural crest markers in the same assay. Inject ion of a dominant-negative form of Zic5 can block neural crest formation in vivo. These results indicate that Zic5 expression converts cells from an e pidermal fate to a neural crest cell fate. This is the first evidence for n eural crest tissue inductive activity separate from anterior neural tissue inductive activity in a Zic family gene. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.