Dynein-mediated pulling forces drive rapid mitotic spindle elongation in Ustilago maydis
Dynein-mediated pulling forces drive rapid mitotic spindle elongation in Ustilago maydis
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DOI：
10.1038/sj.emboj.7601354
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发表时间：
2006-10-18
期刊：
影响因子：
11.4
通讯作者：
Steinberg, Gero
中科院分区：
文献类型：
--
作者：
Fink, Gero;Schuchardt, Isabel;Steinberg, Gero
Spindle elongation segregates chromosomes and occurs in anaphase, an essential step in mitosis. Dynein-mediated pulling forces position the spindle, but their role in anaphase is a matter of debate. Here, we demonstrate that dynein is responsible for rapid spindle elongation in the model fungus Ustilago maydis. We show that initial slow elongation is supported by kinesin-5, which is located in the spindle mid-zone. When the spindle reaches similar to 2 mu m in length, the elongation rate increases four-fold. This coincides with the appearance of long and less-dynamic microtubules (MTs) at each pole that accumulate dynein at their tips. Laser-mediated nanosurgery revealed that these MTs exert pulling forces in control cells, but not in dynein mutants. In addition, dynein mutants undergo initial slow anaphase, but fail to establish less-dynamic MTs and do not perform rapid spindle elongation, suggesting that dynein drives anaphase B. This is most likely mediated by cortical sliding of astral MTs along stationary dynein, which is off-loaded from the MT plus-end to the cortex.
