Fig. 6. Genetic inactivation of one copy of the Bmp4 gene
in a Grem1 mutant background rescues the kinetics of
ureteric epithelial growth and branching. Left panels: GFP reveals the
morphology of the epithelium before fixation. Right panels: whole-mount in
situ detection of the expression of the Ret receptor
(A-C,G-I) and the Gdnf ligand (D-F,J-L).
(A,D,G,J) Wild-type metanephric primordia. (B,E,H,K) Grem1
(G1
/
)-deficient metanephric primordia. Note
the complete disruption of ampulla formation (E,H,K) and loss of mesenchymal
Gdnf expression (K), whereas Ret expression remains in the
arrested epithelium (H). (C,F,I,L) Metanephric primordia of
G1
/
; B4
/+ mouse
embryos. Note the rescue of ureteric epithelial outgrowth (C), branching
(F,I,L) and propagation of Gdnf expression (L).