To measure spindle angles (see Fig. 4 A for schematic), confocal images of metaphase cells in the middle region of the cysts were collected, and the centroid of the cyst (Fig. 4 A, dark blue circle) and center of the spindle axis (Fig. 4 A, pink circles) were drawn using ImageJ (National Institutes of Health). The angle (Fig. 4 A, red) between the spindle axis (Fig. 4 A, black lines) and the line connecting the centroid of the cyst and the center of the spindle (Fig. 4 A, dashed lines) was analyzed. When both spindle poles were not in one z section, three z sections including each spindle pole were taken and merged to draw a line of spindle axis.