Interactions Between Agrobacterium and Host Plants

描述（由申请人提供）：本实验室的目标是继续开发农杆菌-植物病理系统作为宿主-微生物相互作用和信息素介导的细菌通讯的主要模型。在过去的15年里，通过可扩散的化学信号进行的细胞间通讯已被理解为许多细菌的重要特性，特别是与植物，动物或人类宿主相关的细菌。在这些信号中，酰基高丝氨酸内酯（AHLs）在变形菌中特别普遍。AHLs通常由类似于费氏弧菌Luxl蛋白的蛋白质合成，并由类似于费氏弧菌LuxR蛋白的转录因子检测。我的实验室专注于几种LuxR型蛋白质的遗传和生化研究。这些系统之一，根癌农杆菌的Tral和TraR调节大肿瘤诱导质粒的接合和营养复制所需的基因。新洋葱伯克霍尔德氏菌的CepI和CepR调节该细菌的几条染色体和质粒上的许多基因，而小肠结肠炎耶尔森氏菌的YenI和YenR调节未知数量的基因，包括似乎编码小的调节RNA的yenS。我们将继续测试的假设，TraR和CepR需要阿勒正确折叠，必须结合这种信息素在自己的核糖体合成。我们还将研究TraR的激活区域如何与RNA聚合酶相互作用。我们将鉴定由CepR和YenR激活的靶基因。YenR是不寻常的，因为它作为脱辅基蛋白是有活性的，并且其活性被AHLs抑制。我们将尝试在体外重建这种抑制。最后，我们将测试yenS编码小的非编码RNA的想法，并确定该sRNA是否通过形成异源双链来调节靶mRNA的稳定性。YenR和YenS的直接靶标将被鉴定并评估其在Y的生物学和生态学中的作用。enterocolitica和Y.鼠疫

DESCRIPTION (provided by applicant): The goal of this laboratory is continue to the develop the Agrobacterium-plant pathosystem as a leading model for host-microbe interactions and for pheromone-mediated bacterial communication. In the past 15 years, cell-cell communication via diffusible chemical signals has come to be appreciated as an important property of many bacteria, especially those associated with plant, animal, or human hosts. Among these signals, acyl-homoserine lactones (AHLs) are especially widespread among the proteobacteria. AHLs are generally synthesized by proteins resembling the Luxl protein of Vibrio fischeri, and detected by transcription factors resembling the V. ficsheri LuxR protein. My lab focuses on genetic and biochemical studies of several LuxR-type proteins. One of these systems, Tral and TraR of Agrobacterium tumefaciens regulate genes required for the conjugation and vegetative replication of a large tumor-inducing plasmid. Cepl and CepR of Burkholderia cenocepacia regulate many genes on several chromosomes and plasmid of this bacterium, while Yenl and YenR of Yersinia enterocolitica regulate an unknown number of genes, including yenS, which appears to encode a small regulatory RNA. We will continue to test the hypothesis that TraR and CepR require AHL for correct folding, and must bind this pheromone during their own synthesis on ribosomes. We will also study how the activating region or regions of TraR interact with RNA polymerase. We will identify target genes activated by CepR and YenR. YenR is unusual in that it is active as an apo-protein and its activity is inhibited by AHLs. We will try to reconstitute this inhibition in vitro. Finally, we will test the idea that yenS encodes a small non-coding RNA and determine whether this sRNA regulates the stability of target mRNAs by forming heteroduplexes. Direct targets of YenR and YenS will be identified and assessed for their roles in the biology and ecology of Y. enterocolitica and Y. pestis.