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The small molecule Hesperadin reveals a role for Aurora B in correcting kinetochore-microtubule attachment and in maintaining the spindle assembly checkpoint.

Hauf S, Cole RW, LaTerra S, Zimmer C, Schnapp G, Walter R, Heckel A, van Meel J, Rieder CL, Peters JM - J. Cell Biol. (2003)

Bottom Line: We have identified the small molecule Hesperadin as an inhibitor of chromosome alignment and segregation.Our data imply that Hesperadin causes this phenotype by inhibiting the function of the mitotic kinase Aurora B.Hesperadin also causes cells arrested by taxol or monastrol to enter anaphase within <1 h, whereas cells in nocodazole stay arrested for 3-5 h.

View Article: PubMed Central - PubMed

Affiliation: Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, 1030 Vienna, Austria.

ABSTRACT
The proper segregation of sister chromatids in mitosis depends on bipolar attachment of all chromosomes to the mitotic spindle. We have identified the small molecule Hesperadin as an inhibitor of chromosome alignment and segregation. Our data imply that Hesperadin causes this phenotype by inhibiting the function of the mitotic kinase Aurora B. Mammalian cells treated with Hesperadin enter anaphase in the presence of numerous monooriented chromosomes, many of which may have both sister kinetochores attached to one spindle pole (syntelic attachment). Hesperadin also causes cells arrested by taxol or monastrol to enter anaphase within <1 h, whereas cells in nocodazole stay arrested for 3-5 h. Together, our data suggest that Aurora B is required to generate unattached kinetochores on monooriented chromosomes, which in turn could promote bipolar attachment as well as maintain checkpoint signaling.

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Hesperadin quickly overrides the mitotic arrest induced by taxol or monastrol. (A, B, and C) HeLa cells were arrested in nocodazole (330 nM), taxol (10 μM), or monastrol (100 μM). Hesperadin (100 nM) or the solvent DMSO was added, and cells were followed by chromosome spreading (A and B) or immunofluorescence microscopy (C). For immunofluorescence microscopy (C), cells were stained with α-tubulin (left), DNA was counterstained with DAPI (right). (D) Percentage of cells arrested in mitosis in the presence of the different drugs is shown as a function of time. Numbers were obtained from the samples shown in A–C. (E) PtK1 cells were treated with monastrol, and mitotic entry was followed by differential interference contrast microscopy. Selected stills of a time-lapse movie are shown, elapsed time in h:min is shown in the lower right. 500 nM Hesperadin was added at time point 1:10 when the typical monoastral spindle had formed, and mitotic exit was followed. All sister chromatids move into the single polar region.
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fig8: Hesperadin quickly overrides the mitotic arrest induced by taxol or monastrol. (A, B, and C) HeLa cells were arrested in nocodazole (330 nM), taxol (10 μM), or monastrol (100 μM). Hesperadin (100 nM) or the solvent DMSO was added, and cells were followed by chromosome spreading (A and B) or immunofluorescence microscopy (C). For immunofluorescence microscopy (C), cells were stained with α-tubulin (left), DNA was counterstained with DAPI (right). (D) Percentage of cells arrested in mitosis in the presence of the different drugs is shown as a function of time. Numbers were obtained from the samples shown in A–C. (E) PtK1 cells were treated with monastrol, and mitotic entry was followed by differential interference contrast microscopy. Selected stills of a time-lapse movie are shown, elapsed time in h:min is shown in the lower right. 500 nM Hesperadin was added at time point 1:10 when the typical monoastral spindle had formed, and mitotic exit was followed. All sister chromatids move into the single polar region.

Mentions: To investigate the role of Aurora B in chromosome segregation, we performed chromosome spreading of mitotic HeLa cells treated with Hesperadin. Although normal metaphase and anaphase figures (Fig. 4 , a and b) were absent, prometaphase cells showed some degree of chromosome alignment, and chromosomes were frequently bent in the centromeric region (Fig. 4 c, inset, black squares). Such bendings are infrequent in nocodazole-treated cells (compare with Fig. 8 A) and therefore are likely to arise from microtubule attachments. This, and other observations (see below), suggests that most chromosomes become attached to the mitotic spindle when Aurora B is inhibited.


The small molecule Hesperadin reveals a role for Aurora B in correcting kinetochore-microtubule attachment and in maintaining the spindle assembly checkpoint.

Hauf S, Cole RW, LaTerra S, Zimmer C, Schnapp G, Walter R, Heckel A, van Meel J, Rieder CL, Peters JM - J. Cell Biol. (2003)

Hesperadin quickly overrides the mitotic arrest induced by taxol or monastrol. (A, B, and C) HeLa cells were arrested in nocodazole (330 nM), taxol (10 μM), or monastrol (100 μM). Hesperadin (100 nM) or the solvent DMSO was added, and cells were followed by chromosome spreading (A and B) or immunofluorescence microscopy (C). For immunofluorescence microscopy (C), cells were stained with α-tubulin (left), DNA was counterstained with DAPI (right). (D) Percentage of cells arrested in mitosis in the presence of the different drugs is shown as a function of time. Numbers were obtained from the samples shown in A–C. (E) PtK1 cells were treated with monastrol, and mitotic entry was followed by differential interference contrast microscopy. Selected stills of a time-lapse movie are shown, elapsed time in h:min is shown in the lower right. 500 nM Hesperadin was added at time point 1:10 when the typical monoastral spindle had formed, and mitotic exit was followed. All sister chromatids move into the single polar region.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172906&req=5

fig8: Hesperadin quickly overrides the mitotic arrest induced by taxol or monastrol. (A, B, and C) HeLa cells were arrested in nocodazole (330 nM), taxol (10 μM), or monastrol (100 μM). Hesperadin (100 nM) or the solvent DMSO was added, and cells were followed by chromosome spreading (A and B) or immunofluorescence microscopy (C). For immunofluorescence microscopy (C), cells were stained with α-tubulin (left), DNA was counterstained with DAPI (right). (D) Percentage of cells arrested in mitosis in the presence of the different drugs is shown as a function of time. Numbers were obtained from the samples shown in A–C. (E) PtK1 cells were treated with monastrol, and mitotic entry was followed by differential interference contrast microscopy. Selected stills of a time-lapse movie are shown, elapsed time in h:min is shown in the lower right. 500 nM Hesperadin was added at time point 1:10 when the typical monoastral spindle had formed, and mitotic exit was followed. All sister chromatids move into the single polar region.
Mentions: To investigate the role of Aurora B in chromosome segregation, we performed chromosome spreading of mitotic HeLa cells treated with Hesperadin. Although normal metaphase and anaphase figures (Fig. 4 , a and b) were absent, prometaphase cells showed some degree of chromosome alignment, and chromosomes were frequently bent in the centromeric region (Fig. 4 c, inset, black squares). Such bendings are infrequent in nocodazole-treated cells (compare with Fig. 8 A) and therefore are likely to arise from microtubule attachments. This, and other observations (see below), suggests that most chromosomes become attached to the mitotic spindle when Aurora B is inhibited.

Bottom Line: We have identified the small molecule Hesperadin as an inhibitor of chromosome alignment and segregation.Our data imply that Hesperadin causes this phenotype by inhibiting the function of the mitotic kinase Aurora B.Hesperadin also causes cells arrested by taxol or monastrol to enter anaphase within <1 h, whereas cells in nocodazole stay arrested for 3-5 h.

View Article: PubMed Central - PubMed

Affiliation: Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, 1030 Vienna, Austria.

ABSTRACT
The proper segregation of sister chromatids in mitosis depends on bipolar attachment of all chromosomes to the mitotic spindle. We have identified the small molecule Hesperadin as an inhibitor of chromosome alignment and segregation. Our data imply that Hesperadin causes this phenotype by inhibiting the function of the mitotic kinase Aurora B. Mammalian cells treated with Hesperadin enter anaphase in the presence of numerous monooriented chromosomes, many of which may have both sister kinetochores attached to one spindle pole (syntelic attachment). Hesperadin also causes cells arrested by taxol or monastrol to enter anaphase within <1 h, whereas cells in nocodazole stay arrested for 3-5 h. Together, our data suggest that Aurora B is required to generate unattached kinetochores on monooriented chromosomes, which in turn could promote bipolar attachment as well as maintain checkpoint signaling.

Show MeSH