Strickland Laila I, Donnelly Erin J, Burgess David R
Boston College, Chestnut Hill, MA 02467, USA.
Mol Biol Cell. 2005 Oct;16(10):4485-94. doi: 10.1091/mbc.e05-04-0305. Epub 2005 Jul 12.
Astral microtubules (MTs) emanating from the mitotic apparatus (MA) during anaphase are required for stimulation of cytokinesis in eggs. We have used green fluorescent protein-labeled EB1 to observe MT dynamics during mitosis and cytokinesis in normal sea urchin eggs. Analysis of astral MT growth rates during anaphase shows that MTs contact the polar cortex earlier than the equatorial cortex after anaphase onset but that a normal cleavage furrow is not induced until contact with MTs has been achieved throughout the cortex. To assess the role of MT dynamics in initiation of cytokinesis, we used a collection of small molecule drugs to affect dynamics. Hexylene glycol resulted in rapid astral elongation due to decreased MT catastrophe and precocious furrowing. Taxol suppressed MT dynamics but did not inhibit furrow induction when the MA was manipulated toward the cortex. Urethane resulted in short, highly dynamic astral MTs with increased catastrophe that also stimulated furrowing upon being brought into proximity to the cortex. Our findings indicate that astral MT contact with the cortex is necessary for furrow initiation but that the dynamic state of astral MTs does not affect their competency to stimulate furrowing.
后期从有丝分裂器（MA）发出的星体微管（MTs）是卵子中胞质分裂受刺激所必需的。我们使用绿色荧光蛋白标记的EB1来观察正常海胆卵有丝分裂和胞质分裂过程中的微管动态。对后期星体微管生长速率的分析表明，后期开始后，微管与极皮质的接触早于与赤道皮质的接触，但直到整个皮质都与微管接触后才诱导出正常的分裂沟。为了评估微管动态在胞质分裂起始中的作用，我们使用了一系列小分子药物来影响动态。己二醇由于微管灾变减少和过早形成沟而导致星体快速伸长。紫杉醇抑制微管动态，但当将有丝分裂器向皮质操作时并不抑制沟的诱导。氨基甲酸乙酯导致短的、高度动态的星体微管，灾变增加，当靠近皮质时也会刺激沟的形成。我们的研究结果表明，星体微管与皮质的接触是沟起始所必需的，但星体微管的动态状态并不影响它们刺激沟形成的能力。
