Novel ParP Pilus of Myxococcus Xanthus

描述(申请人提供)：IV型菌毛是一种复杂的表面细胞器，位于许多细菌细胞的一个或两个细胞极上。遗传、生化和行为学研究表明，这些结构对运动、转化和接合过程中的DNA摄取、生物膜的形成、致病性和细胞间的交流都是重要的。黄色粘球菌是研究IV型菌毛结构和功能的模式生物之一。在这种细菌中，IV型菌毛与固体表面接触时，会产生社会运动(S)的推进力，这是许多革兰氏阴性细菌使用的一种特殊形式的运动。我们最近从黄花莲中分离到一种新的菌毛，它不同于与S运动有关的IV型菌毛(PilA，23kD，MXAN_5783)。这种新的菌毛由一个称为PARP(MXAN_7475)的16kD蛋白质组成，它位于操纵子内，编码染色体分裂蛋白ParA和PARB，提示菌毛的表达和/或功能与细胞分裂有关。序列分析表明，PARP与IVb型Pilins有相似之处，可能是额外功能的S马达的一部分。这一解释进一步得到了三个重要观察结果的支持：首先，表达PARP菌毛但缺乏冒险-(A)运动性和基于PilA的S运动性的细胞可以作为一组连贯的细胞以S的方式传播，这表明该菌毛代表一种新的分子马达；第二，携带PARP基因敲除的菌株无法聚集和形成子实体，并且在群体分析中显示出S运动性降低；所有这三个特征都是S运动性的特征。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，将进行以下具体目标：1)鉴定PARP，即聚合的菌毛，并鉴定其生物发生所需的基因。2)确定PARP菌毛的作用和出现情况。3)研究PARP、A和B在转录水平的表达，以及这三种蛋白之间可能的相互作用。与公共卫生相关的菌毛是丝状细菌表面结构，是细菌致病性的重要决定因素，在感染过程中发挥重要作用。更好地了解这些结构在模型生物体中的结构、功能和组装可能会导致开发新的策略来对抗细菌感染。

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.