Kinesin-5 recruits HURP to the spindle midzone for robust spindle bipolarity. (A) Loss of HURP accumulation in the central region upon Kinesin-5 inhibition. MII oocytes are shown after monastrol addition, expressing EB3-mCherry (left) and GFP-HURP (right). (B) Longitudinal line scan from oocytes observed in A. Intensity was normalized, and spindle length was interpolated (n = 5). (C) Representative spindle length and relative intensity of HURP fluorescence after monastrol addition. (D) HURP overexpression promotes central spindle assembly and perturbs spindle bipolarization and chromosome congression. GFP-HURP overexpression (see Materials and methods) affects spindle formation and MI division (noninjected: 100% polar body, n = 41; and GFP-HURP overexpression: 7% polar body, n = 67). (E) HURP overexpression disrupts MTOC clustering. Oocytes overexpressing HURP were labeled for DNA and MTOCs (pericentrin, green). (right) Quantification as in Fig. 3 G (n = 5). a.u., arbitrary units. All times are given in hours and minutes after NEBD. Bars, 10 µm.