Expression of the P4.2 transcript during liver development. Shown are bright-field (A, C, E, and G) and dark-field (B, D, F, and H) views of hybridization to the P4.2 antisense riboprobe. (A and B) The liver from an E12.5 (A and B) embryo section; (C and D) the abdominal region containing the liver from an E14.5 (C and D) or E16.5 (E and F) embryo; (G and H) a section of liver from the mouse at 4 weeks after birth. T, thymus; H, heart; L, liver; M, metanephros. Micrographs were taken with a 20× (A, B, G, and H) or 2.5× (C, D, E, and F) objective.