Wild-type and p38γ knockout mice were treated for 6 days with dextran sodium sulfate (DSS) administered in drinking water. a, Representative images showing the shortening of the colon after DSS treatment. b, Immunohistochemical staining (left) and BrdU quantification (right) in colon tissue sections of DSS-treated wild-type and p38γ knockout mice. c, Immunohistochemical staining (left) and phospho-Rb S795 quantification (right). Quantification is shown as mean ± s.e.m. n = 5–10 fields from wild-type control (H2O) mice: n = 5; wild-type DSS-treated mice: n = 7; p38γ KO control mice: n = 5; p38γ KO DSS-treated mice: n = 9. In b, c, comparisons were made using a one-way ANOVA coupled with Bonferroni’s multiple comparison test; **P < 0.01; ***P < 0.001. Scale bar, 100 μm. d, Immunoblot analysis of Rb phosphorylation in the intestine, detected with the indicated antibody; each lane corresponds to a different mouse. The data are representative of at least three independent experiments.