Xenopus brain factor-2 controls mesoderm, forebrain and neural crest development

The forkhead type Brain Factor 2 from mouse and chicken help pattern the fo rebrain, optic vesicle and kidney. We have isolated a Xenopus homolog (Xbf2 ) and found that during gastrulation it is expressed in the dorsolateral me soderm, where it helps specify this territory by downregulating BMP-4 and i ts downstream genes. Indeed, XbfZ overexpression caused partial axis duplic ation. Interference with BMP-4 signaling also occurs in isolated animal cap s, since Xbf2 induces neural tissue. Within the neurula forebrain, Xbf2 and the related Xbf1 gene are expressed in the contiguous diencephalic and tel encephalic territories, respectively, and each gene represses the other. Fi nally, Xbf2 seems to participate in the control of neural crest migration. Our data suggest that XBF2 interferes with BMP-4 signaling, both in mesoder m and ectoderm. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.