Kinesins Are Indispensable for Interdigitation of Phragmoplast Microtubules in the Moss Physcomitrella patens
Kinesins Are Indispensable for Interdigitation of Phragmoplast Microtubules in the Moss Physcomitrella patens
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DOI：
10.1105/tpc.108.061705
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发表时间：
2008-11-01
期刊：
影响因子：
11.6
通讯作者：
Hasebe, Mitsuyasu
中科院分区：
文献类型：
--
作者：
Hiwatashi, Yuji;Obara, Mari;Hasebe, Mitsuyasu
微管形成平行和反平行束阵列，并在各种细胞过程中发挥作用，包括亚细胞运输和细胞分裂。成膜体中的反平行束，植物特有的微管阵列，大多未被探索，并可能提供新的细胞见解。在这里，我们报告说，立碗藓驱动蛋白KINID 1a和KINID 1b（驱动蛋白的叉指状微管1a和1b），这是特定的陆地植物和拟南芥PAKRP 2的正交，是新的因素不可或缺的产生叉指状反平行微管在成膜体的苔藓P. patens。KINID 1a和KINID 1b主要定位于反平行微管的假定交叉部分。这种交错在两个基因的双缺失突变体中消失，表明KINID 1a和1b对于反平行微管阵列的交错是不可或缺的。此外，这些成膜体形成的细胞板没有达到质膜; 20%的突变体细胞检查。我们观察到，在双缺失突变株系中，叶绿体保持在质膜和细胞板的扩展边缘之间，而叶绿体在野生型中不存在于细胞板的边缘。这表明，驱动蛋白，相互交错的反平行微管束，或两者都是必要的细胞壁扩张的适当进展。
Microtubules form arrays with parallel and antiparallel bundles and function in various cellular processes, including subcellular transport and cell division. The antiparallel bundles in phragmoplasts, plant-unique microtubule arrays, are mostly unexplored and potentially offer new cellular insights. Here, we report that the Physcomitrella patens kinesins KINID1a and KINID1b (for kinesin for interdigitated microtubules 1a and 1b), which are specific to land plants and orthologous to Arabidopsis thaliana PAKRP2, are novel factors indispensable for the generation of interdigitated antiparallel microtubules in the phragmoplasts of the moss P. patens. KINID1a and KINID1b are predominantly localized to the putative interdigitated parts of antiparallel microtubules. This interdigitation disappeared in double-deletion mutants of both genes, indicating that both KINID1a and 1b are indispensable for interdigitation of the antiparallel microtubule array. Furthermore, cell plates formed by these phragmoplasts did not reach the plasma membrane in; 20% of the mutant cells examined. We observed that in the double-deletion mutant lines, chloroplasts remained between the plasma membrane and the expanding margins of the cell plate, while chloroplasts were absent from the margins of the cell plates in the wild type. This suggests that the kinesins, the antiparallel microtubule bundles with interdigitation, or both are necessary for proper progression of cell wall expansion.