Figure 5. Human hSPC105 is essential for chromosome segregation, mitotic timing, cytokinesis, and spindle checkpoint activity.
(A) Immunofluorescence imaging of mitotic HeLa cells following treatment with control or targeting siRNA oligos. Cells were stained with anti-hSPC105 antibodies (green), CREST sera (red) and DAPI (DNA, blue). Scale Bar: 10 µm. Insets are 13× magnified. (B) DAPI stained mitotic HeLa cells treated with hSPC105 targeting or control siRNA oligos. (C) Time-lapse imaging of histone 2B-GFP-expressing HeLa cells treated with hSPC105 targeting or control siRNA oligos. Images were collected every 3 min from ∼35 cells; representative frames are shown. In control cells (upper lane) anaphase occurs only after sister chromatid congression is complete, while in hSPC105-depleted cells (lower lane) anaphase is initiated in the presence of unaligned sisters, generating chromosome bridges (yellow arrow). (D) Cell division defects quantified from live-cell imaging experiments. (E) Percentage of nocodazole-treated control and hSPC105-depleted HeLa cells arresting in mitosis (as judged morphologically by DIC microscopy).
