Loss of CYRI results in partial sterility and border cell migration defects. (A) Quantification of cyri mutant female fertility. Single mutant females were mated with wild type males and the total number of offspring reaching adulthood was counted. Transheterozygous mutant cyriΔ11/Df(ED4457) females had substantially reduced fertility and produced fewer offspring compared with wild type. (n = 95; wild type and n = 94; cyriΔ11/Df(ED4457); the red bar represents the median. Mann–Whitney test was used to determine statistical significance: P value<0.001. (B) Brightfield photomicrographs of wild type and cyri mutant eggs. (C) Quantification of micropyle length. (n = 45; wild type and n = 45; cyriΔ11/Df[ED4457]); The red bar represents the median. Mann–Whitney test was used to determine statistical significance: P value: 0.004. Three independent experiments were performed. (D) Schematic drawing of border cell migration during egg development. Polar cells are marked in yellow and border cells in green. (E–G) Maximum intensity projections of three confocal slices of stage 10 egg chambers of the indicated genotypes with DNA (DAPI, blue), F-actin (grey) and anti-EYA (green); anterior is to the left. (E) Wild type egg chamber (F and G) two examples of cyri mutant egg chambers showing prominent lagging border cells. Bars represent 50 μm. (E1) Detailed view of boxed area in E showing wild type border cell cluster arrived the nurse cell-oocyte border. (F1) Detailed view of the boxed area in (F) shows an abnormally elongated border cell cluster with some cells completely detached. (G1–G3) High magnification of boxed areas in G shows cells detached from the main border cell cluster. The scale bar represents 10 µm. (H) Quantification of border cell cluster of indicated genotype with lagging border cells. Statistical significance was determined by Fisher’s exact test, P value <0.001 (wild type: n = 107; cyriΔ11/Df[ED4457]: n = 178). At least three independent experiments for each genotype were performed.