A reliable new cell marker in Xenopus

A new reliable and durable method for marking cells in Xenopus is described. It is based on the differential staining of the nuclei of different Xenopus species, e.g., X. laevis and X. borealis, with the fluorescent dye quinacrine. This method permits us to recognize with certainty each cell in mitosis and interphase of X. borealis origin in any tissue combination with most of the other Xenopus species tested so far. This holds for all stages of development following grafting experiments, including adult tissues. The method is applicable in smears and squash preparations as well as in microtome sections. The method is particularly useful for marking migrating cells which are difficult to track, for instance, in embryos and in the circulatory system.