Dissection of Arabidopsis ADP-RIBOSYLATION FACTOR 1 function in epidermal cell polarity
Dissection of Arabidopsis ADP-RIBOSYLATION FACTOR 1 function in epidermal cell polarity
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DOI：
10.1105/tpc.104.028449
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发表时间：
2005-02-01
期刊：
影响因子：
11.6
通讯作者：
Scheres, B
中科院分区：
文献类型：
--
作者：
Xu, J;Scheres, B
囊泡运输对于不对称的产生至关重要，这是多细胞发育的核心。囊泡转运机制的核心组成部分，如adp -核糖基化因子（ARF） gtp酶，主要在单细胞水平上进行研究。在这里，我们分析了拟南芥多基因ARF家族中ARF1亚类的发育功能。6个几乎相同的ARF1基因普遍表达，这些基因的单个功能缺失突变没有明显的发育表型。荧光共定位研究表明，ARF1定位于洋葱和拟南芥细胞的高尔基体和内吞细胞器。当ARF1突变体在细胞分化早期但在有丝分裂结束后表达时，表皮细胞的顶基极性受到影响，反映在根毛生长的位置。根尖生长和定位过程中的遗传相互作用表明，ROP2蛋白是ARF1作用的靶标，但与高尔基和内吞标记物相比，ARF1操作对其定位的影响较慢。ARF1作用的第二个潜在靶标PIN2的定位也受到慢动力学的影响。尽管极端冗余排除了ARF1功能的传统遗传解剖，但我们的方法分离了参与细胞极性局部和特定方面的不同ARF1下游网络。
Vesicle trafficking is essential for the generation of asymmetries, which are central to multicellular development. Core components of the vesicle transport machinery, such as ADP-ribosylation factor (ARF) GTPases, have been studied primarily at the single-cell level. Here, we analyze developmental functions of the ARF1 subclass of the Arabidopsis thaliana multigene ARF family. Six virtually identical ARF1 genes are ubiquitously expressed, and single loss-of-function mutants in these genes reveal no obvious developmental phenotypes. Fluorescence colocalization studies reveal that ARF1 is localized to the Golgi apparatus and endocytic organelles in both onion (Allium cepa) and Arabidopsis cells. Apical-basal polarity of epidermal cells, reflected by the position of root hair outgrowth, is affected when ARF1 mutants are expressed at early stages of cell differentiation but after they exit mitosis. Genetic interactions during root hair tip growth and localization suggest that the ROP2 protein is a target of ARF1 action, but its localization is slowly affected upon ARF1 manipulation when compared with that of Golgi and endocytic markers. Localization of a second potential target of ARF1 action, PIN2, is also affected with slow kinetics. Although extreme redundancy precludes conventional genetic dissection of ARF1 functions, our approach separates different ARF1 downstream networks involved in local and specific aspects of cell polarity.