Developmental Control and Significance of knotted1 Intercellular Trafficking

结节1细胞间运输的发育控制和意义

• 批准号: 0213025
• 负责人: David Jackson
• 金额: $ 34.5万
• 依托单位: Cold Spring Harbor Laboratory
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0213025&HistoricalAwards=false
• 关键词: Developmental; Control; Significance; knotted1; Intercellular

The development of a multicellular organism requires careful regulation of protein activity and localization. As genome projects are beginning to reveal the complement of genes required to build a plant, scientists now face the complex issue of where and when genes are expressed and where proteins are localized. Imposed on this complexity is the fact that specific plant gene products traffic between cells through specialized channels called plasmodesmata, so their final location may be distant from the cell where they are made. Specifically, some developmental transcription factors are known to traffic between cells, though little is known of the developmental significance and regulation of this process. This project aims to understand the developmental regulation of cell to cell trafficking of plant proteins, using the KNOTTED1 (KN1) gene as a model system. Dominant Kn1 mutants have non-autonomous effects on cell fate in the maize leaf, and using microinjection assays it was shown that KN1 protein and mRNA can traffic between leaf cells, through plasmodesmata. These assays were constrained by the type of tissue that could be targeted, limiting the ability to ask developmentally relevant questions pertaining to the role of KN1 trafficking in its function for stem cell maintenance. Protein fusions of KN1 to the green fluorescent protein were therefore developed and used to visualize trafficking in vivo in intact plant tissues. In the future research, these studies will be extended to ask significant questions about control of plasmodesmal trafficking in the meristem. Specifically, the size exclusion limit of plasmodesmata in the meristem will be estimated, and the experiments will test if symplasmic domains for protein transport exist. Trafficking signal sequences in KN1 will also be localized. The study will contribute to the understanding of cell to cell communication in plants. It will also increase basic knowledge of plasmodesmata, which are poorly characterized at the molecular level. Plasmodesmata are important for the allocation of photosynthetic products, for plant morphogenesis and for defense against pathogens. Therefore these studies of protein trafficking could have significant implications for improving agricultural productivity.

多细胞生物的发育需要仔细调节蛋白质活性和定位。随着基因组计划开始揭示构建植物所需的基因补充，科学家们现在面临着基因表达的地点和时间以及蛋白质定位的复杂问题。 造成这种复杂性的原因是，特定的植物基因产物通过称为胞间连丝的特殊通道在细胞之间运输，因此它们的最终位置可能远离它们产生的细胞。具体而言，已知一些发育转录因子在细胞之间运输，但对该过程的发育意义和调节知之甚少。该项目旨在使用 KNOTTED1 (KN1) 基因作为模型系统，了解植物蛋白的细胞间运输的发育调控。显性 Kn1 突变体对玉米叶中的细胞命运具有非自主影响，显微注射测定表明 KN1 蛋白和 mRNA 可以通过胞间连丝在叶细胞之间运输。 这些检测受到可靶向组织类型的限制，从而限制了提出与 KN1 运输在其干细胞维持功能中的作用有关的发育相关问题的能力。因此，开发了 KN1​​ 与绿色荧光蛋白的融合蛋白，并用于可视化完整植物组织中的体内运输。在未来的研究中，这些研究将扩展到提出有关分生组织胞间连丝运输控制的重要问题。 具体来说，将估计分生组织中胞间连丝的尺寸排除极限，并且实验将测试是否存在用于蛋白质运输的共质结构域。 KN1 中的贩运信号序列也将被本地化。 该研究将有助于理解植物中细胞间的通讯。 它还将增加胞间连丝的基础知识，而胞间连丝在分子水平上的表征还很差。 胞连丝对于光合产物的分配、植物形态发生和防御病原体很重要。因此，这些蛋白质贩运研究可能对提高农业生产力产生重大影响。