ΔCDK-RB expression alters the organization and position of whole chromosomes. Cells were induced to express WT RB or ΔCDK-RB and probed by FISH with probes to chromosome 19 (A–C, F, and G) or chromosome 17 (D, E, and H). (A) The range of signals detected by chromosome 19 probe in cells induced to express WT RB (left) or ΔCDK-RB (right). ΔCDK-RB induces the whole chromosome 19 foci scattering. (B and C) Skeleton dot length was used to place the FISH signals into bins. Graphs show the percentage of foci within each size range (B, left panel), the distribution of skeleton dot lengths and their mean (B, right panel), and the mean number of branches per foci (C). Each parameter increased significantly after ΔCDK-RB expression. (D and E) Similar ΔCDK-RB–induced changes were observed using FISH probe to chromosome 17 foci. (F) Chromosome 19 localizes to nucleolar periphery in ΔCDK-RB–expressing cells. Representative images are shown. (G and H) Quantitation of the shortest distance from the nearest nucleolar signal to chromosome 19 (G) or chromosome 17 (H). Quantitation is from two independent biological replicates, set up and performed on different days. Numbers of foci quantified for each sample (n) are as follows (in the order they appear on the bar graphs): B, n = 77, 60; C, n = 60, 73; D and E, n = 25, 31; G, n = 25, 38; H, n = 20, 28. Error bars are SEM. For B, D (right panels), C, and E, nonparametric two-tailed Mann–Whitney U test was performed, and asterisks denote P values. For B and D (left panels), asterisks denote P values from nonparametric two-tailed multiple t tests (without correction for multiple comparisons). ns, P > 0.05; *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001; ****, P ≤ 0.0001. Scale bar (including insets) = 5 µm.