Plant-specific microtubule-associated protein SPIRAL2 is required for anisotropic growth in arabidopsis
Plant-specific microtubule-associated protein SPIRAL2 is required for anisotropic growth in arabidopsis
复制标题
DOI：
10.1104/pp.104.051748
复制
发表时间：
2004-12-01
期刊：
影响因子：
7.4
通讯作者：
Hashimoto, T
中科院分区：
文献类型：
--
作者：
Shoji, T;Narita, NN;Hashimoto, T
在植物细胞的扩散生长中，皮层微管在调节细胞扩张的方向上起着重要的作用。拟南芥（Arabidopsis thaliana）spiral 2（spr 2）突变体在定向细胞伸长方面有缺陷，并且在纵向扩展的器官如根、下胚轴、茎、叶柄和花瓣中表现出右旋螺旋生长。spr 2根的生长比野生型根的生长对微管相互作用药物更敏感。SPR 2基因编码一种植物特异性的94 kD蛋白，该蛋白含有参与蛋白质-蛋白质相互作用的HEAT重复基序。当组成型表达时，SPR 2-绿色荧光蛋白融合蛋白补充了spr 2突变体表型，并且定位于转基因植物中的皮层微管以及其他有丝分裂微管阵列。重组SPR 2蛋白在体外直接与紫杉醇稳定的微管结合。此外，SPR 2特异性抗体和质谱鉴定了烟草（烟草）SPR 2同源物在高度纯化的微管相关的蛋白质组分从烟草BY-2细胞培养物。这些结果表明，SPR 2是一种新的微管相关蛋白，并参与各向异性生长所需的适当微管功能。
In diffusely growing plant cells, cortical microtubules play an important role in regulating the direction of cell expansion. Arabidopsis (Arabidopsis thaliana) spiral2 (spr2) mutant is defective in directional cell elongation and exhibits right-handed helical growth in longitudinally expanding organs such as root, hypocotyl, stem, petiole, and petal. The growth of spr2 roots is more sensitive to microtubule-interacting drugs than is wild-type root growth. The SPR2 gene encodes a plant-specific 94-kD protein containing HEAT-repeat motifs that are implicated in protein-protein interaction. When expressed constitutively, SPR2-green fluorescent protein fusion protein complemented the spr2 mutant phenotype and was localized to cortical microtubules as well as other mitotic microtubule arrays in transgenic plants. Recombinant SPR2 protein directly bound to taxol-stabilized microtubules in vitro. Furthermore, SPR2-specific antibody and mass spectrometry identified a tobacco (Nicotiana tabacum) SPR2 homolog in highly purified micro tubule-associated protein fractions from tobacco BY-2 cell cultures. These results suggest that SPR2 is a novel microtubule-associated protein and is required for proper microtubule function involved in anisotropic growth.