Elucidation of the new signal transition pathway regarding auxin

阐明生长素的新信号转换途径

• 批准号: 09440263
• 负责人: NAGATA Toshiyuki
• 金额: $ 8.38万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09440263/
• 关键词: auxin; signal trnasduction pathway; tobacco mesophyll protoplasts; cell cycle; dedifferentiation; cytokinin; cell division; DNA合成; プロトプラスト; 信号伝達; 馴化細胞; 転写因子; イオンチャンネル; 出芽コウボ; 2ハイブリッドシシステム; タンパク質キナーゼC

Although auxin was discovered as the first plant hormone, its molecular mechanism is least understood. Thus, this study was-attempted to elucidate signal transduction pathways downstream from auxin application. As we have identified auxin-regulated genes, parA, parB and parC, in our previous study, we further characterized auxin-responsive elements to these genes and subsequetnly showed that there are specific binding proteins to these elements, which are supposed to be involved in auxin-signalling pathways. In the meantime, we found that cytokinin, which is requested for the induction of cell division in tobacco mesophyll protoplasts, was found to play a critical role for the entry into cell cycle. It seems that cell cycle entry was triggered by cytokinin and the cell cycle progression was further facilitated by the gene products of auxin-regulated genes of parA, parB and parC, which encode different types of glutathione S-transferases. This is a completely new interpretation for the … More entry of tobacco mesophyll protoplasts into cell cycle progression, resulting in active cell division.On the other hand, regarding auxin-signalling pathways for tobacco BY-2 cell proliferation, we have identified an auxin-regualted gene, arcA, upon the addition of auxin to the auxin-starved BY-2 cells. In this case, involvement of β-subunit of KィイD1+ィエD1-ion channel proteins was proposed, but we have not gotten decisive conclusion for this pathway. However, we have identified another completely new pathway for auxin signalling. When we added culture filtrates of auxin-habituated 2B-13 cells to the auxin-starved BY-2 cells, we could see the induction of cell division in these cells. This was hot due to the low molecular weight plant hormones in the culture filtrates, but rather to higher molecular mass proteins. Further elucidation of the protein by a gel filtration using Sephadex G25 revealed that it was due to ca. 30 kDa protein. Though the nature of this protein has not been determined yet, it is certain that there is a new signalling pathway downstream from auxin application, as there has been reported no such pathways. Less

虽然生长素是第一个被发现的植物激素，但它的分子机制却知之甚少。因此，本研究试图阐明生长素应用下游的信号转导途径。由于我们已经确定了生长素调控的基因，帕拉，parB和parC，在我们以前的研究中，我们进一步表征了生长素响应元件对这些基因和Escherichia coli表明，有特异性的结合蛋白，这些元件，这应该是参与生长素信号通路。同时，我们发现，细胞分裂素，这是诱导烟草叶肉原生质体细胞分裂所必需的，被发现在进入细胞周期中起着关键作用。这表明细胞分裂素可以触发细胞周期的进入，而生长素调控的基因帕拉、parB和parC编码不同类型的谷胱甘肽S-转移酶的基因产物可以进一步促进细胞周期的进程。这是一个全新的解释， ...更多信息 另一方面，在烟草BY-2细胞增殖的生长素信号途径方面，我们已经鉴定了一个生长素调节基因arcA，当生长素加入到生长素饥饿的BY-2细胞中时。在这种情况下，提出了K β D1+ K β D1-离子通道蛋白β亚基的参与，但我们还没有得到该途径的决定性结论。然而，我们已经确定了另一种全新的生长素信号通路。当我们将生长素适应的2B-13细胞的培养物加入到生长素饥饿的BY-2细胞中时，我们可以看到这些细胞中细胞分裂的诱导。这是热的，因为培养物中的低分子量植物激素，而是高分子量蛋白质。通过使用Sephadex G25的凝胶过滤进一步阐明蛋白质，揭示其是由于ca. 30 kDa蛋白。虽然这种蛋白质的性质尚未确定，但可以肯定的是，在生长素应用的下游存在一种新的信号通路，因为没有报道过这样的通路。少

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