Imaging Cell Migration in Chick Explant Cultures

Abstract

Migratory cells can travel long distances within the embryo to reach peripheral structures. How cells arrive at precise targets remains unclear, largely because of limitations in the ability to resolve how cells respond to microenvironmental signals and communicate positional information to each other. The avian embryo is a good model system for studying cell migration because the embryos are accessible to tissue transplantation, molecular perturbation, cell labeling, and culture outside of the eg. In particular, several clever culture methods have been developed that allow cell migratory behavior to be analyzed in the intact avian embryo or in tissue explants using optical time-lapse microscopy. Furthermore, advances in cell labeling of avian embryos, using either photoactivation or electroporation of green fluorescent protein (GFP) or GFP variants, allow targeted marking of cell subpopulations at discrete points in development. The combination of new culture methods and targeted cell labeling has significantly enhanced the ability to observe and perturb normal cell movements during important early developmental events, such as cranial neural crest migration, gastrulation, and vasculogenesis. This chapter describes a chick explant culture technique that allows visualization of deep cell movements with single cell resolution in older embryos. This technique provides a means to visualize cell migration both along dorsoventral migratory pathways and along the rostrocaudal axis. It also maintains cell resolution without disruptions caused by vibration from the heartbeat.