Circular F-actin bundles and a G-actin gradient in pollen and pollen tubes of Lilium davidii
Circular F-actin bundles and a G-actin gradient in pollen and pollen tubes of Lilium davidii
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百合花粉和花粉管中的圆形 F-肌动蛋白束和 G-肌动蛋白梯度
DOI：
10.1007/s004250100543
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发表时间：
2001-09-01
期刊：
影响因子：
4.3
通讯作者：
Yen, LF
中科院分区：
文献类型：
--
作者：
Li, Y;Zee, SY;Yen, LF
研究了大百合花粉粒和花粉管中f -肌动蛋白和g -肌动蛋白的分布及其相互关系。用共聚焦激光扫描显微镜进行荧光和免疫荧光标记。圆形的f -肌动蛋白束是花粉粒和花粉管中微丝骨架的主要形式。与花粉管内细胞质流动一致，在长花粉管的10 ~ 20母端区没有明显的f -肌动蛋白束，只有少数短的f -肌动蛋白片段。用异硫氰酸荧光素(FITC)- dna酶I标记首先确定了在花粉管的最顶端存在一个以尖端为中心的细胞内g -肌动蛋白浓度梯度，在花粉管顶端10- 20分钟区域的g -肌动蛋白浓度大约是花粉管其他区域的两倍。G-actin的分布与F-actin的分布呈负相关。咖啡因处理导致g -肌动蛋白尖端集中的梯度消失，f -肌动蛋白延伸到花粉管尖端。基于这些结果，我们推测圆形的f -肌动蛋白束可能是花粉管中双向胞质流动的路径，并且在花粉管顶端，大部分f -肌动蛋白解聚为g -肌动蛋白，导致该区域没有f -肌动蛋白束。
The distribution of and relationship between F-actin and G-actin were investigated in pollen grains and pollen tubes of Lilium davidii Duch. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. Circular F-actin bundles were found to be the main form of microfilament cytoskeleton in pollen grains and pollen tubes. Consistent with cytoplasmic streaming in pollen tubes, there were no obvious F-actin bundles in the 10- to 20-mum tip region of long pollen tubes, only a few short F-actin fragments. Labeling with fluorescein isothiocyanate (FITC)-DNase I at first established the presence of a tip-focused gradient of intracellular G-actin concentration at the extreme apex of the tube, the concentration of G-actin being about twice as high in the 10- to 20-mum region of the tip as in other regions of the pollen tube. We also found that the distribution of G-actin was related negatively to that of the F-actin in pollen tubes of L. davidii. Caffeine treatment caused the G-actin tip-focused gradient to disappear, and F-actin to extend into the pollen tube tip. Based on these results, we speculate that the circular F-actin bundles may be the track for bidirectional cytoplasmic streaming in pollen tubes, and that in the pollen tube tip most of the F-actin is depolymerized into G-actin, leading to the absence of F-actin bundles in this region.