Fig. 2. Human SPRY2 expression leads to severe defects in kidney development. When compared with the kidney of a wild-type embryo (A,B), human SPRY2 (TG) expression leads to reduced size of the organ (C,D; E17.5), unilateral agenesis (F, arrow on the right), cystogenesis with a blind-ended hydroureter (F,G,K; F,G, arrows), unilateral lobularization of the kidney (H, stars; E17.5) with cysts (C1-C3 in K; E17.5) or an ectopic second ureteric bud (K1 and K2 in L) when compared with wild-type (WT) controls (A,B,E,I; E17.5). Reduction in the size of the kidney is associated with reduced cell proliferation (M; ^***P<0.005) between the wild-type and transgenic organ in derivatives of the ureteric bud and glomeruli (N,O arrows; E15.5). Human SPRY2 expression also leads to stimulation of apoptosis (P; ^***P<0.005) in derivatives of the ureteric bud and glomeruli (Q,R arrows). Scale bars: 100 µm. K1, host kidney; K2, ectopic kidney; C1-C3, cystic lobules).