Fig. 6.

Secretory cell lineage allocation in intestinal epithelium of FGFR-3^−/− and wild-type mice. A: mRNA levels of secretory cell markers determined by real-time RT-PCR in RNA isolated from total terminal ileum of FGFR-3^−/− and wild-type mice at 7–21 days of age. Although a significant reduction in Paneth cell lysozyme and cryptdin 5 expression was observed in FGFR-3^−/− compared with wild-type mice, chromogranin and Muc2 expression was not different. Values are means ± SE (n = 4 mice per group). P ≤ 0.001 for lysozyme and cryptdin 5 for FGFR-3^−/− vs. wild-type mice at 21 days of age. B and C: immunohistochemical visualization of Paneth cells in cross sections of terminal ileum from 21-day-old wild-type and FGFR-3^−/− mice, respectively, with use of an antibody to lysozyme. D and E: electron micrographs of ultrathin sections of ileum of 21-day-old wild-type and FGFR-3^−/− mice, respectively.