Cargo Transport by Cytoplasmic Dynein Can Center Embryonic Centrosomes
Cargo Transport by Cytoplasmic Dynein Can Center Embryonic Centrosomes
复制标题
通过细胞质动力蛋白进行货物运输可以集中胚胎中心体
作者：
Rafael A. Longoria;G. Shubeita
为了在动物细胞中完成减数分裂II，雄性DNA物质需要与卵中心的雌性原核中所含的雌性DNA物质相遇，但尚不清楚由精子沉积在细胞外围的雄性原核如何在大卵中找到细胞中心。原核定心是一个活跃的过程，似乎涉及微管和分子马达。对于小型和中型细胞，移动中心体所需的力可以来自微管对皮质的推动，或者皮质附着的动力蛋白对微管的拉动。然而，在大细胞中，例如受精的非洲爪蟾胚胎，微管太长而不能支持推力，或者在中心体居中开始之前它们没有到达所有边界，必须存在不同的力产生机制。在这里，我们提出了一个中心体定位模型，在该模型中，由精子星形细胞微管上的细胞质动力蛋白拖曳的货物所经历的胞质阻力可以将中心体移向细胞的中心。我们发现，在实验观察到的长度和时间尺度内，小而快的货物（直径<100 nm，货物速度<2 µm/s）足以移动非洲爪蟾胚胎几何形状中的中心体。
To complete meiosis II in animal cells, the male DNA material needs to meet the female DNA material contained in the female pronucleus at the egg center, but it is not known how the male pronucleus, deposited by the sperm at the periphery of the cell, finds the cell center in large eggs. Pronucleus centering is an active process that appears to involve microtubules and molecular motors. For small and medium-sized cells, the force required to move the centrosome can arise from either microtubule pushing on the cortex, or cortically-attached dynein pulling on microtubules. However, in large cells, such as the fertilized Xenopus laevis embryo, where microtubules are too long to support pushing forces or they do not reach all boundaries before centrosome centering begins, a different force generating mechanism must exist. Here, we present a centrosome positioning model in which the cytosolic drag experienced by cargoes hauled by cytoplasmic dynein on the sperm aster microtubules can move the centrosome towards the cell’s center. We find that small, fast cargoes (diameter ∼100 nm, cargo velocity ∼2 µm/s) are sufficient to move the centrosome in the geometry of the Xenopus laevis embryo within the experimentally observed length and time scales.
DOI：
10.4161/cc.8.8.8150
发表时间：
2009-04-15
期刊：
Cell cycle (Georgetown, Tex.)
影响因子：
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作者：
Wühr M;Dumont S;Groen AC;Needleman DJ;Mitchison TJ
通讯作者：
Mitchison TJ
DOI：
10.1002/cphc.200900113
发表时间：
2009-07-13
期刊：
Chemphyschem : a European journal of chemical physics and physical chemistry
影响因子：
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作者：
Sims PA;Xie XS
通讯作者：
Xie XS