Maisch Jan, Nick Peter
Institute of Botany 1, University of Karlsruhe, D-76128 Karlsruhe, Germany.
Plant Physiol. 2007 Apr;143(4):1695-704. doi: 10.1104/pp.106.094052. Epub 2007 Mar 2.
Polar transport of auxin has been identified as a central element of pattern formation. The polarity of auxin transport is linked to the cycling of pin-formed proteins, a process that is related to actomyosin-dependent vesicle traffic. To get insight into the role of actin for auxin transport, we used patterned cell division to monitor the polarity of auxin fluxes. We show that cell division in the tobacco (Nicotiana tabacum L. cv Bright-Yellow 2) cell line is partially synchronized and that this synchrony can be perturbed by inhibition of auxin transport by 1-N-naphthylphthalamic acid. To address the role of actin in this synchrony, we induced a bundled configuration of actin by overexpressing mouse talin. The bundling of actin impairs the synchrony of cell division and increases the sensitivity to 1-N-naphthylphthalamic acid. Addition of the polarly transported auxins indole-3-acetic acid and 1-naphthyl acetic acid (but not 2,4-dichlorophenoxyacetic acid) restored both the normal organization of actin and the synchrony of cell division. This study suggests that auxin controls its own transport by changing the state of actin filaments.
生长素的极性运输已被确认为模式形成的核心要素。生长素运输的极性与pin形成蛋白的循环相关，这一过程与肌动球蛋白依赖的囊泡运输有关。为深入了解肌动蛋白在生长素运输中的作用，我们利用模式化细胞分裂来监测生长素通量的极性。我们发现烟草（Nicotiana tabacum L. cv Bright-Yellow 2）细胞系中的细胞分裂部分同步，且这种同步可被1-N-萘基邻苯二甲酰胺抑制生长素运输所扰乱。为探究肌动蛋白在这种同步中的作用，我们通过过表达小鼠踝蛋白诱导肌动蛋白形成束状结构。肌动蛋白的成束损害了细胞分裂的同步性，并增加了对1-N-萘基邻苯二甲酰胺的敏感性。添加极性运输的生长素吲哚-3-乙酸和1-萘乙酸（但不是2,4-二氯苯氧乙酸）可恢复肌动蛋白的正常组织和细胞分裂的同步性。这项研究表明，生长素通过改变肌动蛋白丝的状态来控制其自身的运输。
