P-Protein Mutants: Tools to Analyze Phloem Protein Function

9727626汤普森韧皮部对于光同化物从合成或再动员部位到使用或储存部位的长距离运输是必不可少的。尽管韧皮部组织在解剖学和形态学上已经得到了很好的描述，但仍有许多问题需要回答，以将运输细胞的结构成分与其功能联系起来。在许多高等植物中，韧皮部蛋白(P蛋白)丝在运输细胞的细胞质中形成一个完整的网络，但它们的功能尚未解决。该项目的长期目标是将P-蛋白的结构特征与韧皮部生物学联系起来。PI正在利用南瓜属和葫芦科植物中P-蛋白之间的差异来确定这些蛋白中保守特征的功能意义。这些实验将为在转基因植物中进行的功能分析中对这些蛋白质进行广泛的突变分析奠定基础。韧皮部花丝形成所需的结构成分也将在试管中进行评估。人们正在进行实验，以评估韧皮部花丝蛋白中的结合区域，并确定额外的蛋白质，特别是伴侣蛋白在花丝形成中的作用。这些研究将加深我们对P-蛋白的生物学活性和这些蛋白的作用机制的理解。

9727626 Thompson Phloem is essential for the long distance transport of photoassimilates from the sites of synthesis or remobilization to the sites of use or storage. Although phloem tissue has been well described anatomically and morphologically, many questions remain to be answered to link structural components of the translocating cells to their function. Phloem protein (P-protein) filaments form an integral network in the cytoplasm of the translocating cells in many higher plants, yet their function is unresolved. The long term goal of this project is to relate the structural features of P-proteins to phloem biology. The PIs are utilizing the divergence between P-proteins in Cucurbita and Cucumis species to determine the functional significance of conserved features within these proteins. These experiments will be the basis for a broad mutational analysis of these proteins in functional assays performed in transgenic plants. Structural components that are required for phloem filament formation will also be assessed in vitro. Experiments are being conducted to evaluate binding domains in the phloem filament protein and to determine the involvement of additional proteins, especially the role of chaperones, in filament formation. These investigations will enhance our understanding of the biological activity of P-proteins and the mechanisms by which these proteins function.