capt mutant phenotype behind the MF. (A,B) Confocal images of wild-type third instar larval eye imaginal discs stained for Arm (green in A), p-MLC (red in A) and actin (red in B). Lines indicate the position of the MF, and anterior is to the top. Bars, 2 μm. (C) captE636 mutant MARCM clones (GFP, blue) posterior to the MF labeled for DE-cad (green). Inset: High magnification image of three wild-type ICs (indicated by dots, without GFP) shows fragmented AJs (orange arrowheads) at the interface between wild-type (dots) and capt mutant ICs (no dots) as well as fragmented AJs (red arrowheads) at the interface between wild-type ICs (dots). (D) Sagittal section of captE636 mutant MARCM clones (GFP, blue) stained for actin (green) and Dlg (red). The MF and the area posterior to the MF are indicated as an arrow and an arrowhead, respectively. (E) Entirely captE636 mutant eyes (posterior to the MF) stained for actin (red) and Arm (green). Upper inset: captE636 mutant cells under high magnification (indicated by white dashed box in E′) shows AJs formed at regions with proximate F-actin rings (arrowheads). Lower inset: captE636 mutant cells under high magnification (indicated by orange dashed box in E′) shows AJs failed to form at the tricellular junction where F-actin was absent (arrowhead). Anterior is to the top. Bars, 2 μm. (F) captE636 mutant MARCM clones posterior to the MF (arrowhead) labeled for p-MLC (red) and actin (green). Dashed lines indicate clone borders. Lines indicate the position of the MF, and anterior is to the top. Bars, 2 μm. (G-J) Fragmented AJs were relatively stable and did not diffuse laterally towards the tricellular junction. (G,I) Images of ubi-DE-cad-GFP in cultured entirely captE636 mutant eye discs. Boxes in G indicate an area (1500 nm2) of the fragmented AJs before and after bleach, and circles in I indicate an area (350 nm2) of a tricellular junction at zero and 3 min time points. (H) Averaged FRAP recovery curves for fragmented AJs (blue) and wild-type AJs (green). (J) Fluorescence intensity curves for the tricellular junction. Each data point represents the fluorescence intensity measured at each time point divided by the initial fluorescence of the adjacent fragmented AJs. Bars, 2 μm.