Figure 6  Pygo2 is required for BAT-gal reporter expression in ureteric bud-derived structures of the developing kidney. X-Gal staining of BAT-gal transgenic (A-C) E10.5, and (E-L) E13.5 urogenital tracts, and (M-O) E18.5 kidneys. (A) Pygo1-/-/Pygo2+/+ (left) and Pygo1+/-/Pygo2-/- (right). Note the loss of reporter activity in the nephric duct (black arrowhead) and reduction of staining in the ureteric bud (white arrow) of the Pygo2 null embryo (Right). (B) Pygo1-/-/Pygo2+/- E10.5 embryo with BAT-gal reporter activity in the nephric duct (black arrowhead) and ureteric bud (white arrow). (C) Pygo1-/-/Pygo-/- embryo, with reporter expression lost in the nephric duct and reduced in the ureteric bud (white arrow). (D) Control background X-gal staining of a urogenital tract from an E13.5 embryo without the BAT-gal transgene (Non-Tg), showing absence of endogenous beta-galactosidase activity. (E) Pygo1+/-/Pygo2+/+, with BAT-gal reporter activity in the ureteric compartment of the developing kidney, including the ureteric tips, ureteric tree, and ureter. (F) Pygo1+/-/Pygo2-/-, with marked reduction of BAT-gal reporter activity in the ureteric compartment. (G) Pygo1+/-/Pygo2+/-, with reporter expression in the paramesonephric duct (white arrowhead) and ureteric tree. (H, I) Pygo1-/-/Pygo2+/-, with (H) ventral view showing reporter expression in the paramesonephric duct (white arrowhead), and (I) dorsal view showing ureteric tree expression in the kidney. (J)Pygo1+/-/Pygo2+/-, a control processed in parallel with (K) and (L), with expression in ureteric tree and paramesonephric duct. (K, L)Pygo1-/-/Pygo2-/-, reporter activity was lost in the paramesonephric duct (white arrowhead), and in the ureter and ureteric compartment of the developing kidneys (dashed circles), except for (K) a few faintly staining cells. (M, N) Pygo1+/-/Pygo2+/- (left) and Pygo1-/-/Pygo2-/- (right) E18.5 kidneys. The kidneys in (N) were bisected. BAT-gal reporter expression was seen in the ureteric tree components of the cortex and medulla of the double heterozygotes but was almost completely lost in the double-homozygous mutants. (O) Pygo1+/-/Pygo2+/+ (left), Pygo1-/-/Pygo2+/- (middle), and Pygo1-/-/Pygo2-/- (right) E18.5 kidneys. Reporter activity was present in the ureteric compartments of the Pygo1+/-/Pygo2+/+ (left) and Pygo1-/-/Pygo2+/- (middle) kidneys, but lost in the Pygo1-/-/Pygo2-/- (right) kidney. Original magnification: (A-C) × 32, (D-F) × 63, (G-I) × 40, (J-L) × 50, (M, N) × 10, and (O) × 12.5.