Expression and structure of zebrafish VegfA genes and receptors. (A) Zebrafish vegfA exon/intron boundaries were predicted by blasting against the zebrafish genome. The structural similarities between vegfAb171, vegfAa165, and human VEGFA165 suggest that vegfAb171 is an orthologue of human VEGFA165 and similarly, that vegfAb210 is orthologous to human VEGFA189 and/or VEGFA206. (B) Alignment of the cytoplasmic domain of zebrafish Flk1 and human and mouse KDR. Conservation of critical tyrosine residues (arrows) shows that the flk1 RTK described here (Kdrb) is more closely related to KDR than the previously described putative flk1 gene (referred to now as kdra). See “Cloning and analysis of VegfAb and Flk1” for a full description of the critical residues and their function.
