Phenolic/Signal Receptor Interactions in Agrobacterium

本研究将研究酚类物质与特定受体相互作用以引起细胞反应的机制。农杆菌是一个以酚类物质为信号的重要模型系统，它是一种致病土壤细菌，可在受感染植物的伤口部位引起肿瘤。细菌可以将其Ti质粒中的DNA （T-DNA）转移到植物细胞中，并与核DNA整合并表达，最终导致转化细胞的肿瘤生长。Ti质粒中编码T-DNA加工和转移的蛋白质的大部分vir基因直到细菌接收到受伤植物细胞产生的酚类分子后才表达。该信号的假定受体（病毒）已通过遗传手段鉴定为一个92kDa的细胞质膜定位蛋白。提出了苯酚/受体蛋白结合的一个模型，并描述了化学、生化和分子遗传学方法来表征这种相互作用。这个简单的模型系统应该提供深入了解由酚类物质介导的信号转导机制。获得生命过程化学奖，化学学部的合成有机项目和细胞生物科学部的细胞生物化学项目将支持芝加哥大学化学系的David G. Lynn博士和宾夕法尼亚大学生物系的Andrew N. Binns博士的研究。本研究的主要重点是研究酚类物质作为信号分子在真核生物和原核生物中的作用。动物和植物王国中重要的激素和生长因子都属于这类化合物。利用农杆菌模型系统，该项目将探索酚类物质与特定受体相互作用以引发细胞反应的机制。长期的研究目标是为了了解植物的发育。

This research will study the mechanism(s) whereby phenolics interact with specific receptors to elicit cellular responses. An important model system that cues on phenolics as signals is Agrobacterium tumefaciens, a pathogenic soil bacterium that causes tumors at wound sites of infected plants. The bacterium can transfer DNA (T-DNA) from its Ti plasmid into plant cells where it is integrated into the nuclear DNA and expressed, ultimately leading to the tumourous growth of the transformed cells. Most of the vir genes of the Ti plasmid that encode the proteins involved in the processing and transfer of the T-DNA are not expressed until the bacterium receives phenolic molecules produced by wounded plant cells. The putative receptor of this signal (VirA) has been identified by genetic means as a 92kDa cytoplasmic membrane localized protein. A model has been proposed for the phenol/receptor protein association and a description of chemical, biochemical and molecular genetic approaches for the characterization of the interaction have been provided. This simple model system should provide insight into the mechanisms of signal transduction mediated by phenolics. %%% With this Chemistry of Life Processes award, the Synthetic Organic Program of the Chemistry Division and the Cellular Biochemistry Program of the Division of Cellular Biosciences will support the research of Dr. David G. Lynn of the Department of Chemistry of the University of Chicago and Dr. Andrew N. Binns of the Department of Biology of the University of Pennsylvania. The major focus of the research is to study the role of phenolics as signal molecules in both eukaryotic and prokaryotic organisms. Important hormones and growth factors in both the Animal and Plant Kingdoms fall within this class of compounds. Using the model system Agrobacterium tumefaciens, the project will probe the mechanism(s) whereby the phenolics interact with specific receptors to elicit cellular responses. The long-range research goals are directed towards understanding plant development.