Volume 72, Issue 12, Pages 1459-1467 (December 2007) Down the tube of obstructive nephropathies: The importance of tissue interactions during ureter development  R. Airik, A. Kispert  Kidney International  Volume 72, Issue 12, Pages 1459-1467 (December 2007) DOI: 10.1038/sj.ki.5002589 Copyright © 2007 International Society of Nephrology Terms and Conditions

Figure 1 Embryonic development of the ureter in the mouse. Horizontal rows show successive stages characterized by important tissue interactions from ureteric budding at E10.5 (a–e), specification of the ureteric mesenchyme at E11.5 (f–j), ureter elongation at E12.5 (k–o), onset of tissue differentiation at E14.5 (p–t), and establishment of the periureteric peristaltic machinery at E18.5 (u–y). Vertical columns visualize important features of ureter development with respect to the presence and interactions of different tissue compartments. Anterior is up in the first three columns. (a, f, k, p, u) Morphology of isolated urogenital systems (UGS morphology). (b, g, l, q, v) Epithelium of the Wolffian duct and its budding product the ureter (ue) as revealed by whole-mount in situ hybridization analysis for c-ret expression (b), and b-galactosidase activity from a Pax2(8.0)::lacZ transgene specific for the Wolffian duct and its derivatives (g, l, q, v).35 (c, h, m, r, w) Ureteric mesenchyme (um) as revealed by whole-mount in situ hybridization analysis for Tbx18 expression. Arrows in (c) indicate UGS expression of Tbx18. (d, i, n, s, x) Ureter histology as revealed by haematoxylin–eosin staining of 5-μm transverse ureter sections. Rectangles indicate the ureteric epithelium (orange) and the adjacent layer of mesenchyme (yellow). (e, j, o, t, y) Schemes of signaling pathways and tissue interactions between the ureteric epithelium (orange) and the ureteric mesenchyme (yellow). Genes and factors are all mentioned in the text. Ellipses indicate signals that are known to be relevant in ureter development; black arrows indicate secretion from or action on a tissue of a signal; white arrows indicate processes mediated by a signal; dashed arrows indicate positive interactions between factors in a cell. Abbreviations: b, bladder; E, embryonic day; k, kidney; mm, metanephric mesenchyme; SM, smooth muscle; te, testis; ub, ureteric bud; ue, ureteric epithelium; um, ureteric mesenchyme; UGS, urogenital system; ut, ureteric tip; Wd, Wolffian duct. Kidney International 2007 72, 1459-1467DOI: (10.1038/sj.ki.5002589) Copyright © 2007 International Society of Nephrology Terms and Conditions