Mutation of Rice BC12/GDD1, Which Encodes a Kinesin-Like Protein That Binds to a GA Biosynthesis Gene Promoter, Leads to Dwarfism with Impaired Cell Elongation
Mutation of Rice BC12/GDD1, Which Encodes a Kinesin-Like Protein That Binds to a GA Biosynthesis Gene Promoter, Leads to Dwarfism with Impaired Cell Elongation
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DOI：
10.1105/tpc.110.081901
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发表时间：
2011-02-01
期刊：
影响因子：
11.6
通讯作者：
Chong, Kang
中科院分区：
文献类型：
--
作者：
Li, Juan;Jiang, Jiafu;Chong, Kang
动蛋白是一类以微管为基础的马达蛋白家族，它们沿微管定向移动，参与许多关键的细胞过程，包括植物细胞的伸长。人们对直接调节基因转录以影响细胞生理过程的动蛋白知之甚少。在这里，我们描述了一个水稻突变体，赤霉素缺乏矮秆1号(Gdd1)，它的表型是根、茎、穗和种子的长度大大缩短。这种长度的缩短是由于细胞伸长的减少，并可以通过外源赤霉酸(GA3)处理来挽救。利用MAP方法克隆了GDD1，并进行了组成性表达，发现GDD1编码类动蛋白脆性蛋白CULM12(BC12)。微管共构筑分析表明，BC12/GDD1以依赖于ATP的方式与微管结合。全基因组芯片分析显示，编码GA生物合成相关酶的Ent-Kaurene Oxin(KO2)在gdd1中表达下调。电泳迁移率改变和染色质免疫沉淀分析表明，GDD1与KO2启动子中的ACCAACTTGAA元件结合。此外，GDD1还具有反式激活活性。GDD1组内源性GAS水平降低，皮质微管重组改变。因此，BC12/GDD1是一种具有转录调节活性的激动素蛋白，它通过调节水稻GA的生物合成途径来调节细胞的伸长。
The kinesins are a family of microtubule-based motor proteins that move directionally along microtubules and are involved in many crucial cellular processes, including cell elongation in plants. Less is known about kinesins directly regulating gene transcription to affect cellular physiological processes. Here, we describe a rice (Oryza sativa) mutant, gibberellin-deficient dwarf1 (gdd1), that has a phenotype of greatly reduced length of root, stems, spikes, and seeds. This reduced length is due to decreased cell elongation and can be rescued by exogenous gibberellic acid (GA3) treatment. GDD1 was cloned by a map-based approach, was expressed constitutively, and was found to encode the kinesin-like protein BRITTLE CULM12 (BC12). Microtubule cosedimentation assays revealed that BC12/GDD1 bound to microtubules in an ATP-dependent manner. Whole-genome microarray analysis revealed the expression of ent-kaurene oxidase (KO2), which encodes an enzyme involved in GA biosynthesis, was downregulated in gdd1. Electrophoretic mobility shift and chromatin immunoprecipitation assays revealed that GDD1 bound to the element ACCAACTTGAA in the KO2 promoter. In addition, GDD1 was shown to have transactivation activity. The level of endogenous GAs was reduced in gdd1, and the reorganization of cortical microtubules was altered. Therefore, BC12/GDD1, a kinesin-like protein with transcription regulation activity, mediates cell elongation by regulating the GA biosynthesis pathway in rice.