Fig. 1

lhx1a and dusp6 expression marks new nephron formation in the regenerating adult zebrafish kidney. (A) An adult zebrafish with the shape of the kidney highlighted. (B) Diagram of the organization of the adult kidney. Nephrogenic stem cells (Nsc) are colored red and appear in the interstitium and along the renal tubules. Segments of the kidney tubular structure are: CD, collecting duct; Dt, distal tubule; Pt, proximal tubule, Gl, glomerulus. (C–E) Diagram of stem cell based nephrogenesis. Stem cells accumulate on the Dt segment and form aggregates of cells (C). The aggregate elongates into a tubular epithelium and connects to the Dt (D). The new nephron fully differentiates to form a functional nephron (E). (F) Whole mount in situ hybridization of control uninjured adult kidneys show no expression of lhx1a. (G) Seven days after gentamicin injury lhx1a was induced in aggregates of nephrogenic cells, red arrowheads. (H) dusp6 was not expressed in controls but was induced in nephrogenic cells and cell aggregates at 7 dpi, red arrowheads (I). Scale Bars F–I are 500 μm. (J) In histological sections, dusp6 was not expressed in uninjured control kidneys. J-M empty arrowheads indicate dusp6 negative tubules (K) dusp6 was induced by kidney injury in the interstitium and some renal tubules at 3 dpi, in aggregating single cells adjacent to kidney tubules at 5 dpi (L), and highly expressed in nephrogenic aggregates at 7 dpi (M). In K-M, representative dusp6 expressing structures are indicated with solid arrowheads. Scale Bars J-M are 50 μm.