The Xenopus embryo as a model system for studies of cell migration

In this chapter, we describe procedures for the microsurgical removal of cells and tissues from early-stage embryos of the amphibian Xenopus laevis. Using simple culture conditions and artificial substrates, these preparations undergo a variety of quantifiable cellular behaviors that closely mimic cell migration in vivo. Two general methods are described. The first includes procedures for obtaining a dorsal marginal zone explant from early gastrulae in order to investigate the sheet-like extension and migration of the mesendoderm that spreads to cover the inner surface of the blastocoel roof in intact embryos. This preparation allows high-resolution analyses of cellular and subcellular events in a contiguous tissue preparation. The second describes methods for the isolation of cranial neural crest cells from tailbud stage embryos. Cranial neural crest tissue cultured in vitro on fibronectin will undergo segmentation and migrate as streams of cells as they do in the developing head. Each of these robust preparations provides an excellent example of the migratory events that are possible to observe in vitro using amphibian embryos.