Imaging Methods in Xenopus Cells, Embryos, and Tadpoles.

Xenopus is an excellent vertebrate model system ideally suited for a wide range of imaging methods designed to investigate cell and developmental biology processes. The individual cells of Xenopus are much larger than those in many other vertebrate model systems, such that both cell behavior and subcellular processes can more easily be observed and resolved. Gene function in Xenopus can be manipulated and visualized using a variety of approaches, and the embryonic fate map is stereotypical, such that microinjections can target specific tissues and cell types during development. Tissues, organotypic explants, and individual cells can also be mounted in stable chambers and cultured easily in simple salt solutions without cumbersome environmental controls. Furthermore, Xenopus embryonic tissues can be microsurgically isolated and shaped to expose cell behaviors and protein dynamics in any regions of the embryo to high-resolution live-cell imaging. The combination of these attributes makes Xenopus a powerful system for understanding cell and developmental processes as well as disease mechanisms, through quantitative analysis of protein dynamics, cell movements, tissue morphogenesis, and regeneration. Here, we introduce various methods, of both fixed and living tissues, for visualizing Xenopus cells, embryos, and tadpoles. Specifically, we highlight protocol updates for whole-mount in situ hybridization and immunofluorescence, as well as robust live imaging approaches including methods for optimizing the time-lapse imaging of whole embryos and explants.