Expression of GFP in the CD41-GFP embryos. Photomicrographs showing CD41-GFP⁺ expression in transgenic embryos are presented. Unfertilized eggs from homozygous (A) and wild-type (B) females demonstrate the maternally derived GFP. At 48 hpf, bright CD41-GFP⁺ cells are detected in the region between dorsal aorta and caudal vein (arrows, C) and cardiac sinus/yolk sac (arrow near yolk). By 3 dpf, increasing numbers of CD41-GFP⁺ cells are detected in a similar region (arrows near tail, D), and the cardiac sinus/yolk sac (arrow near yolk), as well as in the circulation (D). By 5 dpf, the majority of the CD41-GFP⁺ cells are circulating, and a collection of CD41-GFP⁺ cells appears near the developing mesonephros (arrow, E).