Figure 2.

Varying nucleus size and shape affect t_1/2 at constant values of D_eff in a simulation: each panel shows a different scenario of size and/or shape variation of the nucleus along with the simulated accumulation of GFP-PARP1 in the region of laser damage (box, with unchanged height) and the apparent t_1/2 assuming a D_eff = 4.53 μm²/s and F = 1. The colors of the nuclei correspond to the data in the graph. (A) Three different circular nuclei with radii of 60, 100, and 150 pixels are shown. (B) Three different nuclei of varying ellipticity (100 × 100, 70 × 143, 50 × 200 pixels) but with the same overall area are shown. (C) Three different nuclei of varying size and ellipticity (60 × 60, 60 × 100, 60 × 150 pixels) are shown but, as in (A) and (B), with the same trap size. The black dots superimposed on each curve indicate the best fit to a first-order exponential and demonstrate that size and shape also influence the quality of this fit, which may lead to arbitrary application of multiexponential fitting for larger or more elongated nuclei.