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| Relationship between Microtubules and Cytokinesis When Spindle Interzone Formation Is Disrupted with Topoisomerase II Inhibitors |
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| S.P. Wheatley, C.B. O'Connell and Y.-l. Wang |
| (1998) |
| Mol. Biol. Cell 9:2173-2184. |
| To probe the role of interzonal microtubules in cytokinesis, we blocked the formation of the spindle interzone by treating NRK cells with a topoisomerase II inhibitor, ICRF 187. |
| Abnormal Cytokinesis in Cells Treated with a Topoisomerase II Inhibitor |
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Size = 288 x 192 pixels.| While cytokinesis always takes place in drug treated cells, the site of cleavage is often abnormal. This cell forms a twised furrow away from the equatorial plane as defined by the bulk of chromosomes. |
Size = 288 x 192 pixels.| This cell forms a furrow in the proper location as defined by the of chromosomes, despite the lack of a spindle interzone. However, due to the failure of chromosomal separation, the furrow becomes elongated and distorted in shape. |
| Microtubule-Cortex Interactions Define the Site of Cytokinesis |
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Size = 288 x 192 pixels.| In cells treated with topoisomerase II inhibitors, the lack of a spindle interzone prevents the organization of normal interzonal microtubules. Instead, microtubules emanate from the chromosomal region during anaphase and extend laterally to reach the cortex. The cortical region that comes in contact with microtubules soon starts to ingress. |
| 3D Reconstruction of Microtubules in Cells Treated with Topoisomerase II Inhibitors |
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Size = 192 x 192 pixels.| In cells treated with topoisomerase II inhibitors, a set of microtubules is found to extend laterally from the chromosomal region toward the cortex, as shown in this cell after tracing and reconstructing immunostained microtubules. There is no apparent physical continuity between this set of microtubules and astral or kinetochore microtubules. |