Loss of CYRI affects β-integrin localization in border cell cluster. (A) Schematic drawing of a stage 9 egg chamber. Polar cells are marked in yellow and border cells in green. (A′ and A″) Illustration of migrating border cell cluster that maintains the apico-basal polarity. The apical cap/ring structure is oriented approximately orthogonal to the direction of migration. Highest concentration of E-cadherin is found at the apical interface between border cells and polar cells (apical cap, ring-like structure) and at the contact side between adjacent border cells (BC-BC interface, “arms”). (B–E) Maximum intensity projections of confocal slices of stage 9 egg chambers of the indicated genotypes (wild type: WT; cyri mutant: cyriΔ11/Df(ED4457)) with DNA (DAPI, blue), F-actin (Phalloidin, grey), anti-βPS-integrin (green), and anti-E-cadherin (red); anterior is to the left. (B′–E‴″) Detailed magnified 3D Imaris reconstructions of border cell clusters of boxed areas in B–E. The movement of the border cells proceeds from the left to the right. Scale bars represent 50 μm in B–E and 10 µm in B′–E‴′). (F and G) Quantification of βPS-integrin intensity of indicated genotypes. Statistical significance was determined using the Mann–Whitney test. (F) Trans-heterozygous cyri mutants (cyriΔ11/Df(ED4457): n = 11 and WT: n = 9, P value = 0.031. (G) Overexpression of wild type CYRI transgene under the control of the c306-Gal4 driver, c306 control: n = 14, c306 > CYRI-WT OE: n = 16, P value = 0.070. At least three independent experiments for each genotype were performed.