Fig. 4. Reduction in P53 levels does not ameliorate the phenotype of the Smn^2B/− mouse model.

a Representative images of mice with the various genotypes within experimental litters at P15. Scale bar = 1 cm. b Bar chart (mean ± SEM) shows that there is a significant decrease in P53 at the transcript level in the spinal cord of Smn^2B/+; P53^−/− mice compared to Smn^2B/+; P53^+/+ mice and in Smn^2B/−; P53^−/− mice compared to Smn^2B/−; P53^+/+ mice (by Mann–Whitney-U test, *p < 0.05, **p < 0.001; n = 3 for Smn^2B/−; P53^+/+, n = 4 for all other genotypes). c The graph (mean ± SEM) shows body weight in Smn^2B/+; P53^+/+ and Smn^2B/+; P53^−/− on the left and Smn^2B/−; P53^+/+ and Smn^2B/−; P53^−/− on the right. There is a significant reduction of weight in mice that are P53^−/− in both Smn^2B/+ and Smn^2B/− groups, compared to P53^+/+ mice. Two-way ANOVA with multiple comparison *P < 0.05; *P < 0.001 (d, e) Graphs (mean ± SEM, with individual data points showing mean of three trials for individual animals) shows performance in the time to right test (d) and the time to turn around test (e) for Smn^2B/+; P53^+/+, Smn^2B/−; P53^+/+, Smn^2B/+; P53^−/− and Smn^2B/−; P53^−/− at P8 and P10 (d) and between P12 and P15 (e). In both tests, at all-time points, there is no significant difference in motor performance between Smn^2B/−; P53^−/− and Smn^2B/−; P53^+/+ mice. At P13, 14 and 15, Smn^2B/−; P53^−/− displayed a significantly longer time to turn around than Smn^2B/+; P53^−/− controls. (Kruskal Wallis with Dunn’s multiple comparison test; ns > 0.05, *p < 0.05, **p < 0.01, n = 5 for Smn^2B/+; P53^+/+ and Smn^2B/−; P53^+/+; n = 4 for Smn^2B/+; P53^−/−; n = 3 for Smn^2B/−; P53^−/− for all time points except P15 where n = 4 for Smn^2B/+; P53^+/+ and Smn^2B/+; P53^−/−; n = 6 for Smn^2B/−; P53^+/+ and n = 5 for Smn^2B/−; P53^−/−