Molecular and functional analysis of the mechanism driving cytoplasmic streaming in Arabidopsis thaliana

细胞质流动对于细胞内化合物的分布或它们在细胞中的战略定位是重要的。在植物中，细胞质流动是由肌凝蛋白控制的。讨论了三种类型的原理：通过与肌球蛋白的特定相互作用来动员每种细胞化合物，动员少数细胞器/RNPs，以及通过一些细胞器/RNPs的结合和搅拌液相来动员其他细胞器/RNPs。为了解决这个问题，我们在拟南芥突变体（mya1 mya2 xi-k）中表达了融合到特定锚点的肌球蛋白，该突变体几乎没有细胞质流。表达肌球蛋白锚定蛋白的突变型肌球蛋白系，而不表达携带YFP-YFP而不是锚定蛋白的阴性对照系，显示出生长挽救。我们建议利用这些细胞系来研究不同细胞器/RNPs挽救细胞质流动的能力。此外，我们将通过研究突变系和获救系的细胞形态发生表型、肌动蛋白细胞骨架组织和根毛ROP2信号通路的拯救，来评估不同细胞器/RNPs运动的生物学意义。

Cytoplasmic streaming is important to distribute intracellular compounds or for their strategic positioning in the cell. In plants, cytoplasmic streaming is governed by myosins. Three types of principles have been discussed: the mobilization of each cellular compound through specific interactions with myosins, the mobilization of few organelles/RNPs and comobilization of others by association and stirring of the liquid phase by some organelles/RNPs. To address this, we have expressed myosins fused to specific anchors in an Arabidopsis mutant (mya1 mya2 xi-k) that exhibits virtually no cytoplasmic streaming. Mutant myosin lines expressing myosin-anchor proteins but not lines expressing the negative control carrying an YFP-YFP instead of an anchor show growth rescue. We propose to use these lines to study the ability of different organelles/RNPs to rescue cytoplasmic streaming. In addition we will assess the biological significance of the movement of different organelles/RNPs by studying the rescue of the cell morphogenesis phenotypes, the rescue of the organization of the actin cytoskeleton and ROP2 signaling in root hairs in mutant and rescued lines.