Normal kidney morphogenesis and kidney defects in Looptail mouse. (a) Stages of kidney development: ureteric bud (UB) invades the metanephric mesenchyme (MM) to induce clustering of the nephron progenitor cells above UB tip (cap mesenchyme, CM) to epithelize sequentially into a renal vesicle (RV), comma-shaped body (CB), and S-shaped body (SB). The SB fuses with an arborizing collecting duct (CD) at the distal end and forms a glomerulus (G) at the proximal end. The SB elongates and differentiates to form proximal tubules (PT), loop of Henle (LH), and distal tubules (DT). The shaded areas designate morphogenetic processes where the PCP pathway may be involved. (b) Upper panels: hematoxylin and eosin-stained E17.5 wildtype (left) and Looptail (right) kidneys, magnification ×200; lower panels: WT1 antibody-immunostained wildtype (left) and Lp (right) kidney images, magnification ×100. (c) Upper panels: images of immature (capillary-loop stage) and more mature glomeruli; lower panel: statistical analysis of glomerular developmental delay in Lp versus wildtype kidneys. (d) Electron microscopy of mouse glomerulus (left) and a schematic depiction of the podocyte foot processes along GBM (right): podocyte (P), glomerular basement membrane (GBM), and foot processes (FPs). The results of (b) and (c) were partially published in Rocque, 2014, JASN and are published with the permission of JASN.