Chromosome damage in mitosis induces BubR1 activation and prometaphase arrest.
The effect of double-strand DNA breaks (DSBs) on the spindle assembly checkpoint (SAC) has important implications with respect to the relationship between SAC function and chromosome instability of cancer cells. Here, we demonstrate that induction of DSBs in mitosis results in prolonged hyper-phosphorylation of the SAC protein BubR1 and association of BubR1 with kinetochores in mammalian cells. Combining single cell time-lapse microscopy with immunofluorescence, flow cytometry, and Western blot analysis in synchronized cells, we provide evidence that DSBs activate BubR1, leading to prometaphase arrest. Accordingly, elimination of BubR1 expression by siRNA resulted in the abrogation of mitotic delay in response to chromosome damage. These results suggest that BubR1 links DNA damage to kinetochore-associated SAC function.
Choi
Eunhee
E
Department of Biological Sciences and Research Center for Functional Cellulomics, Seoul National University, San 56-1, Shinlim-dong, Gwanak-ku, Seoul 151-742, Republic of Korea.
Lee
Hyunsook
H
D019457:Chromosome Breakage; D053903:DNA Breaks, Double-Stranded; D006367:HeLa Cells; D006801:Humans; D049468:Prometaphase; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism*
C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases