Skip to main content
. 2005 Mar 31;24(8):1621–1633. doi: 10.1038/sj.emboj.7600641

Figure 3.

Figure 3

The role of Bub1 in chromosome congression is unique among checkpoint proteins. (A, B) Errors in chromosome congression in cells transfected with siRNA as indicated and arrested at the metaphase–anaphase transition for 1 h using MG132. Chromosomes in metaphase cells were counted as unaligned if they were located outside of the central 30% of the mitotic spindle (dotted lines in schematic) or if their kinetochores were aligned perpendicular to the spindle axis. (A) Immunofluorescence of arrested cells stained for CREST (red), tubulin (green) and DNA (blue) following RNAi as indicated. Scale bar: 10 μm. (B) Cumulative plot of number of fraction of cells with maloriented chromosomes; red: 1–2 maloriented chromosomes per cell; blue: 3–4; purple: >4. Numbers above each bar indicate the average number of misaligned chromosomes per cell. Error bars show s.e.m. (C, D) The Bub1, BubR1, Mad2 and CENP-E levels at kinetochores in control and Bub1-depleted cells as quantified using methods described in Figure 1. (C) Cells stained with DAPI (blue), CREST (red) and the indicated antibodies (green). Scale bar: 10 μm. (D) Quantification of protein levels (Bub1, BubR1, Mad2 and CENP-E) on individual kinetochores in control and Bub1-depleted cells as determined from images similar to those in (C). Error bars represent s.e.m. Note that CENP-E is not lost from human kinetochores following Bub1 depletion.