Fig. 7. RARE-lacZ and Raldh3 expression in the eye, olfactory pit and ureteric bud of conditionally rescued Raldh2^–/– embryos. (A) RARE-lacZ staining in the head of an E10.5 Raldh2^–/– embryo treated with RA to E8.25 is shown in a sagittal section. (B,C) Combined detection of Raldh3+Raldh2 mRNAs by whole-mount in situ hybridization at E9.5 using both probes simultaneously for E9.5 Raldh2^–/– (B) and wild-type embryos treated with RA to E8.25 (C); the rescued mutant expresses Raldh3 in the optic vesicle and olfactory pit. (D,E) Higher magnification views of Raldh3 mRNA detection in the head of conditionally rescued Raldh2^–/– embryos at E9.5 (D) and E10.5 (E). (F-H) Analysis of posterior urinary tract of E10.5 Raldh2^–/– embryos treated with RA to E8.25 shows expression of RARE-lacZ in whole-mount and frontal section, respectively (F,G), plus expression of Raldh3 mRNA in whole-mount (H). f, forebrain; m, midbrain; ol, olfactory pit; op, optic vesicle; rpe, retinal pigment epithelium; vr, ventral retina; u, urinary tract.