Fig. 3

Smn missense mutants exhibit elevated melanotic masses. A–C Melanotic mass (MM) data for wandering third instar larvae expressing Smn missense mutations. The data in each panel are a different measure of the melanotic mass phenotypes of the same set of larvae. A Percent of larvae with one or more melanotic mass. Individual data points are the percent of larvae with MMs, 10 larvae per data point. B The average number of melanotic masses per animal. Data points show the number of MMs in each animal. Number (N) = 50 larvae for each genotype. C Qualitative size scoring of the largest melanotic mass in each larva. D Representative images of MMs in animals expressing Smn missense mutations. Bars show the mean, and error bars show the standard error of the mean. Asterisks indicate p-values relative to WT: * < 0.05; ** < 0.01; and *** < 0.001. E Graph showing correlation between the overall phenotypic severity of SMA-causing Smn missense mutations and the number of MMs per animal (from panel B). SMA-like phenotypic severity scores were assigned for each allele (zero being the mildest) based on previously published viability and locomotor assays [20]. Dotted line shows linear regression between data points along with a goodness-of-fit coefficient (R ²)