Dynamics of Eg5 and microtubules in spindles assembled after disruption of the dynein–dynactin complex. (a) Spindle assembled in the presence of p50. Confocal fluorescence microscopy images of photoactivated Eg5-paGFP (green) and Cy5-labeled microtubules (red) before and after photoactivation and simultaneous photobleaching in three different spindle regions. Fluorescence intensity profiles for Eg5-paGFP and Cy5 microtubules (MT) of the same spindle at the indicated times. (b) Sections of intensity difference profiles for bleached Cy5 microtubules and intensity profiles for photoactivated Eg5-paGFP in the halfzone of spindles assembled in the presence of p50 or cc1. (c) Displacements of the peaks of photoactivated Eg5-paGFP (green) and of photobleached Cy5 microtubules (red) along the spindle axis with time. Linear regression fits (lines) to the experimental values (dots) yielded the velocities as indicated. (d) Box plots of the speeds of Eg5 and of microtubule flux (MT) in the halfzone of p50 spindles (11 measurements in 6 spindles) and cc1 spindles (20 measurements in 11 spindles) as compared with wild-type spindles (data from Fig. 3 d). (e) Scatter diagram of speeds of directed movements of photoactivated Eg5-paGFP in the halfzone of p50 spindles (blue), cc1 spindles (green), and in unperturbed spindles (black) as a function of the simultaneously measured speeds of microtubule (MT) flux. (f) Box plots of the half-lives of the fluorescence decays of photoactivated Eg5-paGFP in p50 spindles, cc1 spindles, and unperturbed spindles (data from Fig. 4 b) and box plots of the corresponding residuals. Shown are the same measurements as in section e.