A XENOPUS C-KIT RELATED RECEPTOR TYROSINE KINASE EXPRESSED IN MIGRATING STEM-CELLS OF THE LATERAL-LINE SYSTEM

The mammalian c-kit receptor tyrosine kinase gene is required during e mbryogenesis for the survival and/or proliferation of three migrating stem cell populations: primordial germ cells, haematopoietic stem cell s and neural crest-derived melanoblasts. We have cloned a Xenopus gene , XKrkl, whose closest relative is c-kit. Differences in the expressio n pattern suggest that XKrkl is not the Xenopus homologue of c-kit; ho wever, it is expressed in a migrating stem cell population, the precur sor cells for the mechanosensory lateral line system. XKrkl is the fir st reported marker for lateral line stem cells.