Figure 5

Consequences of E2f3 repression in adult tissues. (a) Quantification of p-H3 positive nuclei per intestinal crypt or field of view of spleen and thymus in control E2f3 ^TRE/TRE; βactin-tTS mice maintained on 50 mg/L tetracycline and control E2f3 ^TRE/TRE mice and E2f3-repressed E2f3 ^TRE/TRE; β-actin-tTS mice following 1 or 2 weeks withdrawal of tetracycline. n = 4 mice, mean of 5 images per mouse; error bars, s.e.m. Mann-Whitney test; P = 0.63(intestine), 0.23(spleen), 0.83(thymus). (b) Quantification of hepatocytes with BrdU positive nuclei per field of view in control (n = 8) and E2f3 ^TRE/TRE; β-actin-tTS (n = 6) mice maintained in the absence of tetracycline for a minimum of 3 weeks (off tetra) and 3 days post induction of liver damage with CCl₄. Mean of 5 images per mouse; error bars, s.e.m. Mann-Whitney test; P = 0.48. (c) Intestinal regeneration was calculated by counting the number of viable crypts and multiplying that by the average size of the regenerating crypts⁵⁰ in control E2f3 ^TRE/TRE and E2f3 ^TRE/TRE; β-actin-tTS mice several weeks post withdrawal of tetracycline (off tetra) and 3 days post exposure to 14 Gy of ionizing radiation. n = 4 mice, mean of 5 images per mouse; error bars, s.e.m. Mann-Whitney test; P = 0.34. (d) Quantification of p-H3 positive nuclei per unit area of epithelial cells in mid-gestation (E10.5) E2f3 ^TRE/TRE and E2f3 ^TRE/TRE; β-actin-tTS mice maintained for several weeks in the absence of tetracycline. n = 3 mice, mean of 5 images per mouse; error bars, s.e.m. Mann-Whitney test; *P = 0.03. Quantification of the number of terminal end buds per 5x field collected from mid-gestation (E10.5) E2f3 ^TRE/TRE and E2f3 ^TRE/TRE; β-actin-tTS mice maintained for several weeks in the absence of tetracycline. n = 3 mice, mean of 3–5 images per mouse. Two-tailed t-test; *P value = 0.03. Controls for (a–d) include E2f3 ^TRE/TRE both on and off tetracycline and E2f3 ^TRE/TRE; β-actin-tTS mice maintained on 50 mg/L tetracycline.