Figure 6.

Condensin I Depletion Causes Molecular Chromatin Lesions in Mitosis

(A) Left, representative images of chromosomal defects in the HCT116 and RPE1 cell lines after siRNA depletion of condensin components CAP-H (condensin I) or CAP-D3 (condensin II) compared with siRNA control (siCTRL). Scale bars, 2.5 μm. Right, quantification of cytogenetic lesions per metaphase after condensin depletion in the HCT116 cell line in the absence (green) or presence (blue) of APH (n > 20 metaphases per condition). p values are for Student’s t test.

(B) Left, representative images of chromosomal defects visualized by FISH at FRA1C (probe A14) and FRA4F (probe A17) fragile sites and control loci (11q13.2, probe P21; 3p21.31, probe C14) in RPE1 and HCT116 cell lines after depletion of the condensin component CAP-H. Scale bars, 5 μm. Right, quantification of abnormal FISH signals, indicative of chromatin disruptions, per metaphase after condensin depletion in the HCT116 and RPE1 cell lines (n > 40 for each condition). p values are for a χ² test.

(C) Left, representative images showing FISH probes at the fragile FRA4F (probe A17) region and at a non-fragile control region (11q13.2, probe P21) after degradation of the condensin I component CAP-H in HCT116 cells. Scale bars, 2.5 μm. Right, quantification of the frequency of irregular FISH signals, indicative of CAP-H-dependent mitotic chromosome misfolding (n > 100 chromosomes per condition). p values are for a χ² test.

NS, not significant; ^∗p < 0.05, ^∗∗p < 0.001, ^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001.

See also Figure S6 and Table S2.