Tension-dependent regulation of microtubule dynamics at kinetochores can explain metaphase congression in yeast
Tension-dependent regulation of microtubule dynamics at kinetochores can explain metaphase congression in yeast
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DOI：
10.1091/mbc.e05-04-0275
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发表时间：
2005-08-01
影响因子：
3.3
通讯作者：
Odde, DJ
中科院分区：
文献类型：
--
作者：
Gardner, MK;Pearson, CG;Odde, DJ
在出芽酵母有丝分裂的中期，姐妹着丝点通过单独连接的着丝点微管（kmt）连接到相反的两极并分离，拉伸其中间的染色质。着丝点运动与单个微管在着丝点附着位点的正端聚合/解聚相耦合。在此，我们使用计算机建模来测试酵母中期控制染色体排列的可能机制，通过模拟实验确定1)着丝粒Cse4-GFP的平均位置，2)着丝粒Cse4-GFP的荧光漂白后恢复（FRAP）测量中期着丝粒的振荡程度，3)gfp -微管蛋白的FRAP测量kmt的动力学，4)未复制的染色体着丝点的平均位置缺乏来自姊妹着丝点的拉力。我们排除了一些可能的模型，并发现理论和实验之间的最佳契合，假设着丝点既能感知抑制两极附近kMT突变的空间梯度，又能感知在染色质拉伸量较高时促进kMT拯救的附着位点张力。
During metaphase in budding yeast mitosis, sister kinetochores are tethered to opposite poles and separated, stretching their intervening chromatin, by singly attached kinetochore microtubules (kMTs). Kinetochore movements are coupled to single microtubule plus-end polymerization/depolymerization at kinetochore attachment sites. Here, we use computer modeling to test possible mechanisms controlling chromosome alignment during yeast metaphase by simulating experiments that determine the 1) mean positions of kinetochore Cse4-GFP, 2) extent of oscillation of kinetochores during metaphase as measured by fluorescence recovery after photobleaching (FRAP) of kinetochore Cse4-GFP, 3) dynamics of kMTs as measured by FRAP of GFP-tubulin, and 4) mean positions of unreplicated chromosome kinetochores that lack pulling forces from a sister kinetochore. We rule out a number of possible models and find the best fit between theory and experiment when it is assumed that kinetochores sense both a spatial gradient that suppresses kMT catastrophe near the poles and attachment site tension that promotes kMT rescue at higher amounts of chromatin stretch.