Figure 8.

The hook mutation alters late endocytic trafficking. HRP-Boss was not detected by antibody staining in R7 cells of hk¹¹ eye disks (A). However, HRP staining revealed that the chimeric protein was internalized into R7 cells (B). By EM (C and D), HRP activity in hk¹¹ R7 cells was detected in tubular early endosomes, small MVBs (arrows), and multilammelar late endosomes or lysosomes (white stars). However, the large mature MVBs, which are a dominant feature of stained wild-type R7 cells, were absent. The relevant genotypes of the larvae were w¹¹¹⁸; hk¹¹ P[w+, gen.HRP-Boss]¹⁷. Bar: A and B, 7.5 μm; C, 200 nm; D, 270 nm.