Ectopic ureteric budding in Gata3^ND−/− embryos.

(A–F) Dissected urogenital systems of control (HoxB7-Cre; Gata3^flox/+; Rosa26^STOPlacZ/+) and Gata3^ND−/− (HoxB7-Cre; Gata3^flox/flox; Rosa26^STOPlacZ/+) embryos were stained for β-Galactosidase activity at the indicated embryonic stages. (A, B) Swelling of the caudal portion of the nephric duct (nd) at E10.5 marks the ureteric bud induction site (ub) in control and Gata3 mutant embryos. (C, D) At E11.5, the ureteric bud of control embryos invades the metanephric mesenchyme to form a T-stage kidney. In Gata3^ND−/− embryos, ectopic buds form along the entire length of the nephric duct (arrowheads). Gata3-deficient embryos frequently fail to induce the primary bud (*). (E, F) At E12.5 the metanephric kidney (k) undergoes its third round of branching morphogenesis in control embryos. In Gata3^ND−/− embryos, some ectopic buds give rise to ectopic kidneys (ek) showing deficient branching morphogenesis, whereas the most rostral buds start to regress. Note the aberrant branch point of the ectopic kidneys (red arrowhead).