Reduction of ATPase activity in the rice kinesin protein Stemless Dwarf 1 inhibits cell division and organ development
Reduction of ATPase activity in the rice kinesin protein Stemless Dwarf 1 inhibits cell division and organ development
复制标题
水稻驱动蛋白 Stemless Dwarf 1 中 ATP 酶活性的降低抑制细胞分裂和器官发育
DOI：
10.1111/tpj.14056
复制
发表时间：
2018-11-01
期刊：
影响因子：
7.2
通讯作者：
Li, Xueyong
中科院分区：
文献类型：
--
作者：
Fang, Jingjing;Yuan, Shoujiang;Li, Xueyong
几个运动蛋白，atp驱动的微管（MT）为基础的运动蛋白，已被报道参与植物发育的许多基本过程；然而，对其atp酶活性的生物学相关性知之甚少。本研究以水稻（Oryza sativa）无茎矮化1 （std1）突变体为研究对象，该突变体具有严重矮化表型，其节和节间结构无分化，细胞形状异常，叶片分裂区缩短，细胞分裂率降低。进一步的分析显示，大量细胞在S期和G2/M期被阻滞，std1突变体中存在多核细胞。基于图谱的克隆发现，STD1编码一种phragmoplast-associated kinesin-related protein，与拟南芥PAKRP2同源，主要在活跃分裂组织中表达。STD1蛋白在末期和细胞质分裂期间特异定位于片质体中间区。在std1突变体中，Val-40-Glu在std1运动结构域的替换显著降低了其mt依赖性atp酶活性。因此，在细胞质分裂过程中，细胞膜的横向扩张被阻止，这是细胞板形成的关键步骤。因此，这些结果表明mt依赖性atp酶活性是STD1调节正常细胞分裂和器官发育所必需的。
Several kinesins, the ATP-driven microtubule (MT)-based motor proteins, have been reported to be involved in many basic processes of plant development; however, little is known about the biological relevance of their ATPase activity. Here, we characterized the Oryza sativa (rice) stemless dwarf 1 (std1) mutant, showing a severely dwarfed phenotype, with no differentiation of the node and internode structure, abnormal cell shapes, a shortened leaf division zone and a reduced cell division rate. Further analysis revealed that a substantial subset of cells was arrested in the S and G2/M phases, and multinucleate cells were present in the std1 mutant. Map-based cloning revealed that STD1 encodes a phragmoplast-associated kinesin-related protein, a homolog of the Arabidopsis thaliana PAKRP2, and is mainly expressed in the actively dividing tissues. The STD1 protein is localized specifically to the phragmoplast midzone during telophase and cytokinesis. In the std1 mutant, the substitution of Val-40-Glu in the motor domain of STD1 significantly reduced its MT-dependent ATPase activity. Accordingly, the lateral expansion of phragmoplast, a key step in cell plate formation, was arrested during cytokinesis. Therefore, these results indicate that the MT-dependent ATPase activity is indispensible for STD1 in regulating normal cell division and organ development.