Fig. 4.
Analysis of fusion dynamics and ATP dependence. (A) The red curve shows the dynamics of a single example control fusion event of two GFP∷NPM1–labeled nucleoli, shown by the images in the red box. The blue curve shows the slower fusion dynamics of a comparable pair of GFP∷NPM1 nucleoli (blue boxes) in an ATP-depleted GV. The red outline in the images is the output of the image analysis routines used to calculate aspect ratio. (B) Plot of the fusion time, τ, vs. length, ℓ, from untreated nucleoli (N = 77), and apyrase-treated nucleoli (N = 46). The red and blue lines are linear fits to the control and apyrase data, respectively. (C) Scatter plot of η/γ obtained from control and ATP-depleted nucleoli. The Right axis reflects the apparent viscosity, ηapp, obtained assuming a surface tension of γ = 10 μN/m.