Novel ParP Pilus of Myxococcus Xanthus

描述（由申请人提供）：IV型皮利是位于许多细菌细胞的一个或两个细胞极上的复杂表面细胞器。遗传、生物化学和行为研究已经证明，这些结构对于运动性、转化和接合期间的DNA摄取、生物膜形成、致病性和细胞间通讯是重要的。研究IV型皮利结构和功能的模式生物之一是黄色粘球菌。在这种细菌中，IV型皮利在与固体表面接触时产生用于社会（S）运动的推进力，这是许多革兰氏阴性细菌使用的运动的特殊形式。我们最近从M. xanthus，其不同于参与S-运动的充分表征的IV型菌毛（PilA，23 kD，MXAN_5783）。这种新型菌毛由称为ParP（MXAN_7475）的16 kD蛋白质组成，其位于编码染色体分配蛋白帕拉和ParB的操纵子内，表明菌毛表达和/或功能与细胞分裂之间的联系。序列分析表明，ParP与IVb型菌毛蛋白有相似之处，可能是一个额外的功能性S-电机的一部分。这种解释进一步得到了三个重要观察结果的支持：第一，表达ParP菌毛但缺乏冒险性（A）运动性和基于PilA的S运动性的细胞可以以S样方式作为连贯的细胞群扩散，表明菌毛代表新的分子马达;第二，携带parP敲除的菌株不能聚集和形成子实体，并且在群集测定中显示出降低的S运动性;所有这三个特征都是S运动的标志。为了研究ParP菌毛在粘细菌复杂的生活史和协调行为中的作用，本论文的主要目的是：1）研究ParP菌毛的特性，并鉴定其生物发生所需的基因。2)定义ParP皮利的作用和发生。3)研究ParP、A和B的转录表达以及这三种蛋白质之间可能的相互作用。公共卫生相关性皮利是丝状细菌表面结构，是细菌致病性的重要决定因素，在感染过程中起主要作用。更好地了解模型生物中这些结构的结构，功能和组装可能会导致开发对抗细菌感染的新策略。

DESCRIPTION (provided by applicant): Type IV pili are complex surface organelles that are located on one or both cell poles of many bacterial cells. Genetic, biochemical, and behavioral studies have demonstrated that these structures are important for motility, DNA uptake during transformation and conjugation, biofilm formation, pathogenicity, and cell-to-cell communication. One of the model organisms to study the structure and function of type IV pili is Myxococcus xanthus. In this bacterium type IV pili generate the propulsive force for social- (S)-motility, a specialized form of motility that is used by many gram-negative bacteria, when in contact with a solid surface. We have recently isolated a novel pilus from M. xanthus that is distinct from the well-characterized type IV pilus involved in S-motility (PilA, 23 kD, MXAN_5783). This novel pilus is composed of a 16 kD protein termed ParP (MXAN_7475) that is located within the operon encoding the chromosomal partitioning proteins ParA and ParB suggesting a link between pilus expression and/or function and cell division. Sequence analysis suggests that ParP shares similarities with type IVb pilins and may be part of an additional functional S-motor. This interpretation is further supported by three important observations: First, cells expressing the ParP pilus but lacking both adventurous- (A)-motility and PilA-based S-motility can spread as coherent groups of cells in an S-like fashion indicating that the pilus represents a novel molecular motor; second strains carrying a parP knockout are unable to aggregate and form fruiting bodies and show reduced S-motility in swarming assays; all three features are hallmarks of S-motility. To study the role of the ParP pilus in the complex life cycle and coordinated behaviors of myxobacteria, the following specific aims will be undertaken: 1) Characterize ParP, the polymerized pilus, and identify genes required for its biogenesis. 2) Define the role and occurrence of ParP pili. 3) Study the transcriptional expression of ParP, A, and B as well as possible interactions between these three proteins. PUBLIC HEALTH RELEVANCE Pili are filamentous bacterial surface structures that are important determinants of bacterial pathogenicity and play a major role during infectious processes. A better understanding of the structure, function, and assembly of these structures in a model organism may result in the development of new strategies to fight bacterial infections.