THE FORMATION OF THE PRONEPHRIC DUCT IN XENOPUS INVOLVES RECRUITMENT OF POSTERIOR CELLS BY MIGRATING PRONEPHRIC DUCT CELLS

Cell migration and cell-cell interactions play important roles in numerous processes during embryogenesis. One of these is the formation of the pronephric (Wolffian) duct (PD), which connects the pronephros to the cloaca. It is currently accepted that in most amphibians the pronephric duct is formed by active migration of the pronephric duct rudiment (PDR) cells along a predetermined pathway. However, there is evidence that in Xenopus, the PD may be formed entirely by in situ segregation of cells out of the lateral mesoderm. In this study, we show, using PDR ablation and Xenopus laevia-Xenopus borealis chimeras, that PD elongation in Xenopus requires both active cell migration and an induced recruitment of cells from the posterior. We also show that PDR cell migration is limited to only a few stages during development and that this temporal control is due, at least in part, to changes in the competence of the PD pathway to support cell migration. © 1993 Academic Press, Inc.