Fig. 4

Expression of ~ 10–20% of WT dysferlin protein levels is sufficient for normal membrane repair. a Representative images showing time-dependent accumulation of FM-64 dye following laser-induced membrane damage of flexor digitorum muscle fibers (FDBs) in whole FDB muscle harvested from 40aKO mice (KO-1-to-KO-3), WT and dysferlin-null mice aged 4–6 months. White arrows point to the site of irradiation at 45 s post injury. b Comparison of FM-64 dye curves of each line, gathered from images captured at 3 s intervals, including the duration of irradiation (gray area), until 60 s. FM-64 dye begins to rise as soon as irradiation is complete at 5 s. c Quantification of the area under the curve (AUC) of each line in (a). There is no significant difference in the average AUC of 40aKO mice and WT, indicating normal membrane repair capacity in all 40aKO lines. In contrast, the average AUC of dysferlin null fibers is at least twice that of WT and 40aKO, indicative of defective membrane repair. Dots in graph (b) represent numbers of FDBs assessed per genotype, Dysf.^−/− = 22, KO-1 = 50, KO-2 = 42, KO-3 = 51, WT = 11. Data is represented as mean ± SEM. Differences were tested by One-way ANOVA with Tukey’s multiple-comparisons test. ***p < 0.001