Collective cell migration of the nephric duct requires FGF signaling

Background: During the course of development, the vertebrate nephric duct (ND) extends and migrates from the place of its initial formation, adjacent to the anterior somites, until it inserts into the bladder or cloaca in the posterior region of the embryo. The molecular mechanisms that guide ND migration are poorly understood. Results: A novel Gata3‐enhancer‐Gfp‐based chick embryo live imaging system was developed that permits documentation of ND migration at the individual cell level for the first time. FGF Receptors and FGF response genes are expressed in the ND, and FGF ligands are expressed in surrounding tissues. FGF receptor inhibition blocked nephric duct migration. Individual inhibitors of the Erk, p38, or Jnk pathways did not affect duct migration, but inhibition of all three pathways together did inhibit migration of the duct. A localized source of FGF8 placed adjacent to the nephric duct did not affect the duct migration path. Conclusions: FGF signaling acts as a “motor” that is required for duct migration, but other signals are needed to determine the directionality of the duct migration pathway. Developmental Dynamics 244:157–167, 2015. © 2014 Wiley Periodicals, Inc. Key Findings FGF signaling is required for nephric duct migration in the chick embryo. FGF appears to act via multiple signal transduction pathways to regulate duct migration. A localized FGF source does not divert the duct migration path.