Fig. 2. Expression of Foxd1^lacZ in heterozygous and mutant embryos. At E13.5 (A,B) there is strong Foxd1^lacZ expression in the dorsal body wall and kidneys, as well as a trail of ß-gal⁺ cells that leads into the capsule of the kidney (arrowheads). At E16.5 (C,D), this trail is thinner (left arrowheads) and a gap between the normal kidney and the dorsal body wall exists (C, right arrowheads), while the mutant kidney is still attached (D, right arrowhead). In wild type (C'), there are both round ß-gal⁺ cells in the loose connective tissue between the kidney and the dorsal body wall (yellow arrowheads) and flattened ß-gal⁺ cells in the renal capsule (red arrowheads). In the mutant (D'), there is a mixture of ß-gal⁺ and ß-gal^- cells in the capsule (red arrowheads). At E18.5, the wild-type capsule (E) still consists of a single layer of ß-gal⁺ cells (red arrowheads), which persists into early adulthood (G). At E18.5, the mutant capsule is thickened (F,F') and still contains a mixture of ß-gal⁺ (blue arrowheads) and ß-gal^- cells (red arrowheads). Higher magnification of bracketed areas in C, D, and F are displayed in (C',D',F'). d, dorsal; v, ventral; cs, cortical stroma. Scale bar: 400 µm for C,D; 250 µm for A,B; 120 µm for C',D'; 75 µm for E,F; 20 µm for G,F'.