ISOLATION OF THE ZEBRAFISH HOMOLOGS FOR THE TIE-1 AND TIE-2 ENDOTHELIUM-SPECIFIC RECEPTOR TYROSINE KINASES

Several characteristics of the zebrafish embryo make it an attractive model in which to study the development of the cardiovascular system. The utility of the zebrafish as a model of mammalian vascular developm ent will depend on the conservation of molecular and morphogenetic mec hanisms of vessel growth. Here, we report the cloning of the zebrafish homologues of the endothelium-specific receptor tyrosine kinases tie- 1 and tie-2. The Z tie-2 clone represents the first report of a full-l ength zebrafish endothelium-specific gene. The zebrafish tie family me mbers have significant structural homology with their murine and human counterparts. In addition, like the murine tie-1 and tie-2 genes, exp ression was found predominantly in endothelial cells. At 24-hr postfer tilization (HPF), Z tie-1 was expressed in all observed populations of endothelial cells. Interestingly, Z tie-2 exhibited a similar, althou gh slightly more restricted, expression pattern. Taken together, these data strongly suggest that mechanisms of vascular development are hig hly conserved across species and that zebrafish will continue to be a useful model for the investigation of vertebrate embryonic vascular de velopment. (C) 1998 Wiley-Liss, Inc.