Mitotic defects caused by CLD depletion. (A) FACS analysis of control and CLD-depleted Kc167 cells. The graph shows the distribution of the DNA content of control and dsRNA-treated cells after a 4-d incubation with dsRNA. Ploidy is shown on the x axis. A high number of polyploid cells accumulated after CYCA and RCA1 depletion. A milder effect on ploidy was observed in CENP-C–depleted cells. (B) The number of defective mitoses was quantified after a 4-d incubation with control (no RNA; n = 38), CID (n = 53), CENP-C (n = 50), CAL1 (n = 58), CYCA (n = 31), or RCA1 (n = 34) dsRNA. n represents the number of cells examined in each condition. The percentage of cells with abnormal prometaphase or metaphase figures is shown on the left, and the percentage of cells with abnormal anaphase or telophase figures is shown on the right. The data are taken from a single experiment, but a duplicate experiment yielded similar results. (C) Still frames from time-lapse experiments of mitotic defects associated with RNAi depletion of CLDs in cells expressing mCherry-tubulin and H2B-GFP. Control cells (left) displayed accurate and timely chromosome segregation. CID-, CENP-C–, and CAL1-depleted cells showed a dramatic mitotic delay, little to no chromosome movement, abnormally elongated and defective spindles, and chromosome missegregation; nevertheless, cytokinesis occurred. CYCA depletion caused defective spindles, missegregation of chromosomes, and cytokinesis defects. RCA1 depletion predominantly caused a cell cycle arrest; most cells did not divide after RNAi treatment. Times are minutes from the start of the video (see Videos 6 [control], 7 [CID-RNAi], 8 [CENP-C–RNAi], 9 [CAL1-RNAi], and 10 [CYCA-RNAi], available). Bars, 5 μm.