Fig. 4

osi downregulation is associated with a smaller cell size. A Osi is expressed in the fat body. mCherry expression driven by osi^Gal4 shows strong consistent signal in the fat body. B Confocal images of a fat body of larvae expressing Osi-FLAG under actG4, stained for Flag (in red). Scale bar represents 50 μm (A) and 100 μm (B). C–G osi mutants develop cellular defects in time. C, D Representative confocal images of fat body of control and mutant animals at 72h stained with DAPI (nucleus) and phalloidin (cell outline). Scale bar represents 20 μm. E–G Quantification of cellular area of larval fat bodies of 24h (E), 48h (F), and 72h (G) AEL individuals of control, heterozygous, and homozygous mutants. Five or six fat bodies were photographed per genotype on each time point. Dots in each graph represent individual cell sizes. H GFP directed by pplG4 confirms fat body expression. Bars represent 20 μm. I–K: Phalloidin and DAPI stained fat bodies from 72h AEL control (I) and larvae expressing osi^RNAi under pplG4 (J). Bars represent 10 μm. K Larvae expressing osi^RNAi show reduced cell size. Quantitation of cell size of fat body cells from 72h AEL control and larvae expressing osi^RNAi under pplG4. Three fat bodies were photographed per genotype. Dots in each graph represent individual cell sizes. All graphs describe the mean ± SEM. In E, F, and G, a Kruskal-Wallis with Dunn’s multiple comparisons test was performed. In K, a Mann-Whitney test was performed. All panels: the total number of observations is indicated under each data set. A Shapiro-Wilk test was used for normality assessment (see Additional file 2). Different letters indicate significant differences, p<0.05; treatments sharing any letter are not statistically different. The total number of samples analyzed is detailed below the corresponding dataset. All datasets and statistical analysis on which the conclusions are based are included in Additional file 2