Figure 3—figure supplement 1.

(A) Coinjection of RNAs encoding Rab5-GFP and Flag-Ryk-Myc reveals that 70.7% of Ryk-expressing intracellular compartments are positive for the early endosomal marker Rab5 (n = 75 cells from eight embryos analyzed). Arrowheads in A’’ indicate compartments that are positive for Rab5 only (green), Ryk only (magenta), or present both markers (white). (B,C) Mib1 overexpression promotes the internalization of Ryk-GFP but not the one of the plasma membrane marker GAP43-RFP (n = 4). (D,E) RNAs encoding Ryk-GFP and Histone2B-mRFP were injected with increasing amounts of mib1 RNA. While a low dose of Mib1 relocalizes Ryk from the plasma membrane to intracellular compartments (n = 6), high amounts of Mib1 cause an overall loss of Ryk signal (n = 6). D’-F’, The Histone2B-mRFP signal was used to ascertain that embryos had received a comparable amount of injected material. (D-F and D’-F’) are sum projections of three consecutive slices from confocal stacks. All pictures depict dorsal views of 90% epiboly stage embryos, anterior up. Scalebars: 10 µm in A-C, 20 µm in D-F.