Novel roles for the flagellum in cell morphogenesis and cytokinesis of trypanosomes
Novel roles for the flagellum in cell morphogenesis and cytokinesis of trypanosomes
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DOI：
10.1093/emboj/cdg518
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发表时间：
2003-10-15
期刊：
影响因子：
11.4
通讯作者：
Bastin, P
中科院分区：
文献类型：
--
作者：
Kohl, L;Robinson, D;Bastin, P
鞭毛和纤毛是从原生动物到哺乳动物保存下来的精细的细胞骨架结构，在那里它们完成与运动性或敏感性相关的功能。在这里，我们证明了鞭毛在控制原生动物布鲁氏锥虫的细胞大小、形状、极性和分裂中的新作用。为了研究鞭毛的功能，诱导性RNA干扰沉默鞭毛内运输所需的组分，这是鞭毛组装所必需的动态过程，从而扰乱了鞭毛的形成。首先，我们发现鞭毛内运输的下调导致较短鞭毛的组装。引人注目的是，鞭毛较短的细胞更小，鞭毛长度与细胞大小直接相关。详细的形态发生分析表明，新鞭毛的尖端定义了细胞质分裂开始的点。其次，当新的鞭毛形成被完全阻断时，非鞭毛细胞非常短，失去了正常的形状和极性，不能进行细胞分裂。我们发现鞭毛伸长控制细胞骨架结构的形成（存在于细胞体中），作为细胞的分子组织者。
Flagella and cilia are elaborate cytoskeletal structures conserved from protists to mammals, where they fulfil functions related to motility or sensitivity. Here we demonstrate novel roles for the flagellum in the control of cell size, shape, polarity and division of the protozoan Trypanosoma brucei. To investigate the function of the flagellum, its formation was perturbed by inducible RNA interference silencing of com ponents required for intraflagellar transport, a dynamic process necessary for flagellum assembly. First, we show that down-regulation of intraflagellar transport leads to assembly of a shorter flagellum. Strikingly, cells with a shorter flagellum are smaller, with a direct correlation between flagellum length and cell size. Detailed morphogenetic analysis reveals that the tip of the new flagellum defines the point where cytokinesis is initiated. Secondly, when new flagellum formation is completely blocked, non-flagellated cells are very short, lose their normal shape and polarity, and fail to undergo cytokinesis. We show that flagellum elongation controls formation of cytoskeletal structures (present in the cell body) that act as molecular organizers of the cell.