SPIRAL1 encodes a plant-specific microtubule-localized protein required for directional control of rapidly expanding Arabidopsis cells
SPIRAL1 encodes a plant-specific microtubule-localized protein required for directional control of rapidly expanding Arabidopsis cells
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DOI：
10.1105/tpc.017830
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发表时间：
2004-05-01
期刊：
影响因子：
11.6
通讯作者：
Hashimoto, T
中科院分区：
文献类型：
--
作者：
Nakajima, K;Furutani, I;Hashimoto, T
高度组织化的间期皮层微管（MT）阵列对于植物细胞的各向异性生长至关重要，但人们对建立和维持这些阵列顺序的分子机制知之甚少。拟南芥螺旋 (spr1) 突变体在根和黄化的下胚轴中显示出右旋螺旋生长。突变表型的表征表明，SPR1 可能通过 MT 依赖性过程控制各向异性细胞扩张。 SPR1 通过基于图谱的克隆进行鉴定，发现它编码一种功能未知的小蛋白质。与 SPR1 同源的蛋白质特异且普遍存在于植物中。与绿色荧光蛋白融合蛋白的遗传互补表明，SPR1 蛋白与皮质 MT 共定位，并且 MT 定位和细胞扩增控制都是由保守的 N 端和 C 端区域赋予的。在细胞快速伸长的组织中发现了强烈的 SPR1 表达。过表达 SPR1 的植物表现出对 MT 药物的抗性增强和下胚轴伸长增加。这些观察结果表明，SPR1 是一种植物特异性 MT 定位蛋白，是维持快速伸长细胞的生长各向异性所必需的。
Highly organized interphase cortical microtubule (MT) arrays are essential for anisotropic growth of plant cells, yet little is known about the molecular mechanisms that establish and maintain the order of these arrays. The Arabidopsis thaliana spirals (spr1) mutant shows right-handed helical growth in roots and etiolated hypocotyls. Characterization of the mutant phenotypes suggested that SPR1 may control anisotropic cell expansion through MT-dependent processes. SPR1 was identified by map-based cloning and found to encode a small protein with unknown function. Proteins homologous to SPR1 occur specifically and ubiquitously in plants. Genetic complementation with green fluorescent protein fusion proteins indicated that the SPR1 protein colocalizes with cortical MTs and that both MT localization and cell expansion control are conferred by the conserved N- and C-terminal regions. Strong SPR1 expression was found in tissues undergoing rapid cell elongation. Plants overexpressing SPR1 showed enhanced resistance to an MT drug and increased hypocotyl elongation. These observations suggest that SPR1 is a plant-specific MT-localized protein required for the maintenance of growth anisotropy in rapidly elongating cells.