Nsp1p depletion creates two cell populations with distinct NPC linear densities. (A) Shown is an electron micrograph of PMET3-NSP1 cells after depletion of Nsp1p (+Met 4 h). The positions of NPCs are visible as gaps (≤100 nm across) within the NE (arrowheads). Bar, 2 µm. (B) PMET3-NSP1 cells and PMET3-NUP170 nup157Δ cells were incubated with methionine for the indicated times and subjected to the EM analysis. Transmission EM images containing sections through the nucleus were selected and the linear density of NPCs for each nuclear section was calculated (NPCs per micrometer of the NE). For each time point, the number of NPCs per micrometer in individual sections (x axis) is plotted versus its percentile rank within the dataset of sections examined (n; black points). The gray line in each graph represents a cumulative Poisson distribution estimated on an assumption that NPCs were randomly distributed throughout the NE. Also plotted is the deviation of the observed NPC density (black) from the theoretical distribution for each rank (gray).
