Living Xenopus oocytes, eggs, and embryos as models for cell division.

Xenopus laevis has long been a popular model for studies of development and, based on the use of cell-free extracts derived from its eggs, as a model for reconstitution of cell cycle regulation and other basic cellular processes. However, work over the last several years has shown that intact Xenopus eggs and embryos are also powerful models for visualization and characterization of cell cycle-regulated cytoskeletal dynamics. These findings were something of a surprise, given that the relatively low opacity of Xenopus eggs and embryos was assumed to make them poor subjects for live-cell imaging. In fact, however, the high tolerance for light exposure, the development of new imaging approaches, new probes for cytoskeletal components and cytoskeletal regulators, and the ease of microinjection make the Xenopus oocytes, eggs, and embryos one of the most useful live-cell imaging models among the vertebrates. In this review, we describe the basics of using X. laevis as a model organism for studying cell division and outline experimental approaches for imaging cytoskeletal components in vivo in X. laevis embryos and eggs.