RNAi screening identifies the armadillo repeat-containing kinesins responsible for microtubule-dependent nuclear positioning in Physcomitrella patens
RNAi screening identifies the armadillo repeat-containing kinesins responsible for microtubule-dependent nuclear positioning in Physcomitrella patens
复制标题
RNAi 筛选鉴定出包含犰狳重复序列的驱动蛋白，负责小立碗藓中微管依赖性核定位
DOI：
10.1093/pcp/pcv002
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发表时间：
2015
影响因子：
4.9
通讯作者：
and Gohta Goshima
中科院分区：
文献类型：
--
作者：
Tomohiro Miki;Momoko Nishina;and Gohta Goshima
细胞核的正确定位对各种细胞的功能至关重要。肌动蛋白和肌球蛋白已被证明是至关重要的细胞核定位在植物细胞中，而微管（MT）为基础的机制通常用于动物和真菌细胞。在这项研究中，我们结合活细胞显微镜与RNA干扰（RNAi）筛选或药物治疗，并表明，MT和植物特异性的马达蛋白，包含驱动蛋白（驱动蛋白-ARK），需要在mossPhyscomitrella patens的核定位。在顶端生长的原丝体顶端细胞中，细胞分裂后，细胞核以MT依赖的方式移位到细胞的中心。当使用RNAi敲除驱动蛋白-ARKs时，细胞核向中心的初始移动正常发生;然而，在到达中心之前，细胞核被移回细胞的基底边缘。在完整的（对照）细胞，MT束与驱动蛋白ARKs经常观察到周围的移动核。与此相反，这样的MT束后，驱动蛋白ARK下调没有确定。体外MT滑动试验表明，驱动蛋白ARK是一种正末端定向运动蛋白。这些结果表明，MT和MT为基础的电机驱动核迁移的苔藓细胞，从而显示了保护的机制核定位之间的植物，动物和真菌细胞。
Proper positioning of the nucleus is critical for the functioning of various cells. Actin and myosin have been shown to be crucial for the localization of the nucleus in plant cells, whereas microtubule (MT)-based mechanisms are commonly utilized in animal and fungal cells. In this study, we combined live cell microscopy with RNA interference (RNAi) screening or drug treatment and showed that MTs and a plant-specific motor protein, armadillo repeat-containing kinesin (kinesin-ARK), are required for nuclear positioning in the mossPhyscomitrella patens. In tip-growing protonemal apical cells, the nucleus was translocated to the center of the cell after cell division in an MT-dependent manner. When kinesin-ARKs were knocked down using RNAi, the initial movement of the nucleus towards the center took place normally; however, before reaching the center, the nucleus was moved back to the basal edge of the cell. In intact (control) cells, MT bundles that are associated with kinesin-ARKs were frequently observed around the moving nucleus. In contrast, such MT bundles were not identified after kinesin-ARK down-regulation. An in vitro MT gliding assay showed that kinesin-ARK is a plus-end-directed motor protein. These results indicate that MTs and the MT-based motor drive nuclear migration in the moss cells, thus showing a conservation of the mechanism underlying nuclear localization among plant, animal and fungal cells.