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Fig. 5. Survivin depletion decreases BubR1 abundance at kinetochores of maloriented
chromosomes. (A,B) Immunofluorescence images of control (A) and
Survivin-depleted cells 60 hours post-transfection (B). Cells are stained for
BubR1 (red), Survivin (green) and DNA (blue). Panels A'-B' show the BubR1
status of the inset regions indicated in a thermal scale where blue indicates
a low signal intensity, green intermediate intensity and yellow-red high.
Panels A"-B" show enlargements of the lagging chromosomes shown in
the insets stained with DAPI and ACA. Unattached chromosomes of control cells
have a high BubR1 signal (A'), while both high (B', upper chromosome) and low
signal intensities (B", lower chromosome) are found on unattached
chromosomes of a Survivin-depleted cell. (C) Chromosome spreads of HeLa cells
following transfection with control or Survivin siRNA. Cells were treated for
2 hours with 0.1 µg/ml colcemid to depolymerize microtubules. In all panels
Survivin is shown in green and DNA in blue. Top panels show BubR1 in red and
lower panels show centromeres in red. All kinetochores are potentially capable
of expressing high levels of BubR1 following Survivin depression. (D) Control
and Survivin-depleted cells were treated with 0.1 µg/ml colcemid for 12
hours from 60 hours post transfection. A Survivin-positive and a
Survivin-depleted cell are shown. BubR1 (red, D"), Survivin (greyscale,
D'), centromeres (green) and DNA (blue). Survivin-depleted cell shows no BubR1
staining at the kinetochores. Bars, 5 µm.