Jagged-notch signaling in zebrafish pronephros development

Abstract

Jagged-Notch pathway genes and essential kidney developmental gene pax2a and pax8 are dynamically expressed in the different segment of the zebrafish pronephros. In the tubule and distal duct segments, Jagged2a-Notch signaling mediates multi-cilia cells and principal cells differentiation through lateral inhibition mechanism and Pax2a/Pax8 control differentiation process by regulating the jagged2a expression. In the tubule segment, Jagged1b/Jagged2a-Notch signaling and Pax2a/Pax8 form a positive feedback loop and this feedback loop is required for the maintenance of tubule. Jagged(s)-Notch signaling positively regulates pax2a expression through effector Odd-skipped related 2 (Odd2) by lateral induction mechanism. Therefore, a single ligand, Jagged2a, could do both lateral inhibition and lateral induction within a single tissue, in this case, tubule at different timing. Finally, Fgf ligands secreted from somite were found to activate tubule pax2a early in development through effecter Pea3 from 4 s to 15 s. In Fgf defective embryos tubule cells are reduced due to lower level of Pax2a-Notch feedback loop.