Fig. 6. Regulation of Cdx1 by RA. Expression of Cdx1 in E7.5 (A,B,E,F) or E8.5 (C,D,G,H) wild-type (A-D) and LRE mutant (E-H) mouse embryos following in utero treatment with DMSO vehicle (A,C,E,G) or RA (100 mg/kg; B,D,F,H). Embryos were processed and stained in parallel, with mutants stained four times longer than controls to reveal residual expression.