Defective endosomal trafficking in the ema mutant. (A and B) Endosomal trafficking of the fluorescent endocytic tracer avidin-Cy3. Garland cells were incubated with avidin-Cy3 for 5 min and chased for the indicated time period (min). (A) Representative confocal images of garland cells traced with avidin-Cy3 (red) and stained for the plasma membrane marker HRP (blue) and nuclear marker Nissl (blue). Bar, 5 µm. (B) Line-depth intensity plot of avidin-Cy3 tracer. (Black) wild type (Canton S), (red) ema1, and (gray) rescue (ema1; Actin5C-Gal4/UAS-EmaGFP). n > 10 for all genotypes at all chase times. Data represent mean ± SEM. (C and D) Ultrastructural analysis of endosomal trafficking of the endocytic tracer HRP in garland cells. (C) Representative transmission electron micrograph of HRP-labeled endosomes, with electron-dense lumen in wild type (arrow) and electron-lucent lumen in mutant. Electron-dense HRP tracers highlight the limiting membrane and intraluminal protrusions (arrowheads) in mutant. Bar, 500 nm. (D) Quantification of HRP-labeled endosomes. n = 191 for 8 wild-type cells; n = 16 for 6 mutant garland cells. Data represent mean ± SEM.
