CLEAVAGE OF THE BMP-4 ANTAGONIST CHORDIN BY ZEBRAFISH TOLLOID

Dorsoventral patterning of vertebrate and Drosophila embryos requires bone morphogenetic proteins (BMPs) and antagonists of BMP activity. Th e Drosophila gene tolloid encodes a metalloprotease similar to BMP-1 t hat interacts genetically with decapentaplegic, the Drosophila homolog of vertebrate BMP-2/4. Zebrafish embryos overexpressing a zebrafish h omolog of tolloid were shown to resemble loss-of-function mutations in chordino, the zebrafish homolog of the Xenopus BMP-4 antagonist Chord in. Furthermore, Chordin was degraded by COS cells expressing Tolloid. These data suggest that Tolloid antagonizes Chordin activity by prote olytically cleaving Chordin, A conserved function for zebrafish and Dr osophila Tolloid during embryogenesis is proposed.