Zebrafish have emerged as a powerful model organism to study embryo 
morphogenesis. Due to their optical clarity, they are uniquely suited for 
time-lapse imaging studies, providing insights into the dynamic processes 
underlying tissue formation and cell migration. These studies have been 
tremendously facilitated by the availability of transgenic zebrafish lines, 
labelling distinct embryonic structures, individual cells, or even subcellular 
structures, such as the nucleus. Zebrafish studies have revealed that the 
migration of several different cell types in the embryo is controlled by 
chemokines, small vertebrate-specific proteins. Here, we report methods to 
analyze the expression pattern of a given chemokine and its receptor in 
transgenic zebrafish using fluorescent in situ hybridization in combination with 
an anti-green fluorescent protein (GFP) antibody staining. We furthermore 
illustrate how to image migrating cell populations using time-lapse microscopy 
in double-transgenic embryos. We show how to investigate cell number and 
direction of migration by using a nuclear-localized GFP. The combination of this 
transgene with a membrane-targeted red fluorescent protein allows for the 
simultaneous determination of changes in cell shape, such as the formation of 
filopodial extensions. We exemplify this by describing how a mutation in the 
chemokine receptor cxcr4a affects endothelial cell migration and blood vessel 
formation. Finally, we provide a method to perform fluorescent angiography to 
monitor blood vessel perfusion in chemokine receptor mutants.