Analyzing Morphogenetic Cell Behaviors in Vitally Stained Zebrafish Embryos

Owing to its extremely rapid rate of development, as well as its optical transparency, the zebrafish embryo provides an excellent experimental system for analyzing the cellular dynamics that underlie vertebrate body axis formation. Moreover, the zebrafish (Danio rerio ) is very amenable to genetic manipulation. Recent large-scale saturation mutagenesis screens have isolated several thousand strains of Danio rerio that possess recessive mutant alleles for genes involved in pattern formation or morphogenesis (1 ,2 ). These mutant strains of zebrafish represent a wealth of experimental material from which the patterns of cell division, cell intercalation, cell migration, and coordinate cell shape changes that underlie zebrafish morphogenesis can be analyzed. To help determine the genetic and epigenetic mechanisms that choreograph these events, it is often very useful to follow the morphogenetic behaviors of single cells and cell populations within the living zebrafish embryo.