Organization and dynamics of growing microtubule plus ends during early mitosis
Organization and dynamics of growing microtubule plus ends during early mitosis
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DOI：
10.1091/mbc.e02-09-0607
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发表时间：
2003-03-01
影响因子：
3.3
通讯作者：
Cassimeris, L
中科院分区：
文献类型：
--
作者：
Piehl, M;Cassimeris, L
使用表达EB 1-绿色荧光蛋白的稳定细胞系来成像生长中的微管正末端在G2/M转变。到后期前期，生长端不再延伸到细胞周边，并且不均匀地分布在每个中心体周围。在核膜周围的区域中，生长末端要丰富得多，并且在核周围生长的微管比在相反方向生长的微管长1.5倍。长末端向细胞核方向的生长并不是由于局部较快的生长速率，因为从中心体向各个方向的生长速率都接近于11 μ m/min。相反，微管末端向细胞核生长似乎是由与核膜相关的动力蛋白/动力肌动蛋白稳定的。将p50注射到晚期前期细胞中，从核膜中去除动力蛋白，降低核膜附近生长末端的密度，并导致每个中心体的生长末端均匀分布。我们认为，细胞周期依赖性结合的动力蛋白/动力蛋白的核膜局部稳定增长的微管。如最近的研究所述，动力蛋白和微管都将参与核膜的破坏。
A stable cell line expressing EB1-green fluorescent protein was used to image growing microtubule plus ends at the G2/M transition. By late prophase growing ends no longer extend to the cell periphery and were not uniformly distributed around each centrosome. Growing ends were much more abundant in the area surrounding the nuclear envelope, and microtubules growing around the nucleus were 1.5 fold longer than those growing in the opposite direction. The growth of longer ends toward the nucleus did not result from a localized faster growth rate, because this rate was similar to11 mum/min in all directions from the centrosome. Rather, microtubule ends growing toward the nucleus seemed stabilized by dynein/dynactin associated with the nuclear envelope. Injection of p50 into late prophase cells removed dynein from the nuclear envelope, reduced the density of growing ends near the nuclear envelope and resulted in a uniform distribution of growing ends from each centrosome. We suggest that the cell cycle-dependent binding of dynein/dynactin to the nuclear envelope locally stabilizes growing microtubules. Both dynein and microtubules would then be in a position to participate in nuclear envelope breakdown, as described in recent studies.