Microtubule-destabilizing/stabilizing drugs affect meiosis I spindle length and orientation. (A and C) Spindle length and pole depth from the chorion were estimated from z sections (0.5-μm steps) of fixed whole-mount klp10A-gfp (A) or klp10A NT–-gfp oocytes (C) either untreated or treated with colchicine or taxol. Mean ± SEM (error bars). (B) Schematic diagram illustrating the effects of colchicine and taxol on spindle length, angle, and depth relative to the cortex in klp10A-gfp oocytes. Both drugs cause the spindle to move deeper into the oocyte and orient more vertically to the cortex.