Microtubule flux mediates poleward motion of acentric chromosome fragments during meiosis in insect spermatocytes
Microtubule flux mediates poleward motion of acentric chromosome fragments during meiosis in insect spermatocytes
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DOI：
10.1091/mbc.12.12.4054
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发表时间：
2001-12-01
影响因子：
3.3
通讯作者：
Rieder, CL
中科院分区：
文献类型：
--
作者：
LaFountain, JR;Oldenbourg, R;Rieder, CL
我们应用激光显微手术和定量偏光显微镜相结合，研究染色体臂减数分裂过程中的起重机飞精母细胞的动力学独立的力量。当位于前中期或中期的半纺锤体之一的染色体臂被激光切割时，产生的无着丝粒片段（缺乏动粒）以类似于后期染色体的速度（类似于0.5 μ m/min）向极移动。为了确定这种分离臂向极运动的机制，我们用微管稳定药物紫杉醇处理精母细胞。在紫杉醇处理的细胞中的Spectroms明显短，但与偏振光，微管的分布和密度的域片段运动发生的是没有不同的控制细胞。当紫杉醇处理的精母细胞产生无着丝粒碎片时，24个碎片中有22个没有表现出向极运动，而两个确实运动的碎片的速度衰减了80%（近似于0.1 μ m/min）。在这些细胞中，紫杉醇并不抑制染色体的分离，也不阻止其在后期向极分离，但后期的速度也降低了80%（类似于0.1 μ m/min）相对于未经处理的对照组。总之，这些数据表明，微管流量施加极定向力染色体臂减数分裂期间在起重机飞精母细胞，并强烈建议，微管流量的机制也被用于后期运动的动粒在这些细胞。
We applied a combination of laser microsurgery and quantitative polarization microscopy to study kinetochore-independent forces that act on chromosome arms during meiosis in crane fly spermatocytes. When chromosome arms located within one of the half-spindles during prometaor metaphase were cut with the laser, the acentric fragments (lacking kinetochores) that were generated moved poleward with velocities similar to those of anaphase chromosomes (similar to0.5 mum/min). To determine the mechanism underlying this poleward motion of detached arms, we treated spermatocytes with the microtubule-stabilizing drug taxol. Spindles in taxol-treated cells were noticeably short, yet with polarized light, the distribution and densities of microtubules in domains where fragment movement occurred were not different from those in control cells. When acentric fragments were generated in taxol-treated spermatocytes, 22 of 24 fragments failed to exhibit poleward motion, and the two that did move had velocities attenuated by 80% (to similar to0.1 mum/min). In these cells, taxol did not inhibit the disjunction of chromosomes nor prevent their poleward segregation during anaphase, but the velocity of anaphase was also decreased 80% (similar to0.1 mum/min) relative to untreated controls. Together, these data reveal that microtubule flux exerts pole-directed forces on chromosome arms during meiosis in crane fly spermatocytes and strongly suggest that the mechanism underlying microtubule flux also is used in the anaphase motion of kinetochores in these cells.