Organizational Innovation of Apical Actin Filaments Drives Rapid Pollen Tube Growth and Turning
Organizational Innovation of Apical Actin Filaments Drives Rapid Pollen Tube Growth and Turning
复制标题
顶端肌动蛋白丝的组织创新驱动花粉管快速生长和转向
DOI：
10.1016/j.molp.2017.05.002
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发表时间：
2017-07-05
期刊：
影响因子：
27.5
通讯作者：
Huang, Shanjin
中科院分区：
文献类型：
--
作者：
Qu, Xiaolu;Zhang, Ruihui;Huang, Shanjin
极化尖端生长是许多真核生物的基本细胞过程。在这项研究中，我们研究了拟南芥花粉尖端生长过程中肌动蛋白细胞骨架的动态重组及其与囊泡运输的关系。我们发现，源自顶膜的肌动蛋白丝形成了一种特殊的结构，由皮层纵向排列的肌动蛋白束和具有独特分布的内部细胞质丝组成。使用基于肌动蛋白的药物治疗和基因突变体结合 FRAP（光漂白后荧光恢复）技术来可视化花粉管生长域内囊泡的运输，我们证明了皮质肌动蛋白丝促进了向尖端的囊泡运输。我们还发现内部顶端肌动蛋白丝可以防止囊泡向后移动，从而确保花粉管尖端积累足够的囊泡以支持花粉管的快速生长。皮质和内部顶端肌动蛋白丝的组合效应完美地解释了花粉管尖端倒“V”锥形囊泡分布模式的产生。当花粉管转动时，正面的顶端肌动蛋白丝发生解聚和再聚合，使顶端肌动蛋白结构重新定向到新的生长方向。这种肌动蛋白重组先于囊泡积累和管形态的变化。因此，我们的研究为花粉管之间的功能关系提供了新的见解。快速定向花粉管生长期间的肌动蛋白动力学和囊泡运输。
Polarized tip growth is a fundamental cellular process in many eukaryotes. In this study, we examined the dynamic restructuring of the actin cytoskeleton and its relationship to vesicle transport during pollen tip growth in Arabidopsis. We found that actin filaments originating from the apical membrane form a specialized structure consisting of longitudinally aligned actin bundles at the cortex and inner cytoplasmic filaments with a distinct distribution. Using actin-based pharmacological treatments and genetic mutants in combination with FRAP (fluorescence recovery after photobleaching) technology to visualize the transport of vesicles within the growth domain of pollen tubes, we demonstrated that cortical actin filaments facilitate tip-ward vesicle transport. We also discovered that the inner apical actin filaments prevent backward movement of vesicles, thus ensuring that sufficient vesicles accumulate at the pollen tube tip to support the rapid growth of the pollen tube. The combinatorial effect of cortical and internal apical actin filaments perfectly explains the generation of the inverted "V'' cone-shaped vesicle distribution pattern at the pollen tube tip. When pollen tubes turn, apical actin filaments at the facing side undergo depolymerization and repolymerization to reorient the apical actin structure toward the new growth direction. This actin restructuring precedes vesicle accumulation and changes in tube morphology. Thus, our study provides new insights into the functional relationship between actin dynamics and vesicle transport during rapid and directional pollen tube growth.