(B) Confocal microscopy images of fixed nuclei assembled for 120 min in mock depleted (mock) and Nup50 depleted (∆Nup50) Xenopus egg extracts supplemented with recombinant mouse Nup50 orthologues. Nuclei were stained for Nup50 (Nup50 antibody for Xenopus protein, His6 for mouse protein) and NPCs (mAB414, red) on the chromatin (DAPI). Scale bar: 10 µm. (C) The average percentage of mAB414 positive nuclei for 100 randomly chosen chromatin substrates in each of three independent experiments (performed as in B) is shown. Data points from individual experiments are indicated. 