Function of Mg1 Proteins in Gliding in Myxococcus

Mg1 蛋白在粘球菌滑动中的功能

• 批准号: 9206996
• 负责人: Patricia Hartzell
• 金额: $ 18万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-15 至 1996-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9206996&HistoricalAwards=false
• 关键词: Function; Mg1; Proteins; Gliding; Myxococcus

The long range goal of this project is to understand the mechanism of surface translocation, or gliding, in myxobacteria. The survival of a diverse group of environmentally important organisms, including myxobacteria, cytophaga, cyanobacteria, and Beggiotoa, depends upon their ability to glide. In this project, Myxococcus xanthus will be used as a model to understand gliding because it is genetically well-characterized. One gene, mglA, is essential for gliding; the focus of this project will be on how MglA protein interacts with other motility components. Since mglA is the only gene common to the two known genetically-identified systems, A and S, that control gliding, MglA protein may affect expression of A- and S-gliding genes. The first aim will therefore be to isolate and characterize reporter gene (lacZ) insertions in A- and S-motility genes and determine if their transcription is altered in an mgl- strain. Another goal will be to use mutagenesis to probe the functional domains of MglA by identifying mglA mutants that show aberrant gliding. Suppressor experiments have also been designed to identify genes encoding proteins that interact with MglA. One mutant has already been identified that suppresses the mglA defect, and the corresponding gene will be cloned to determine if it encodes a gliding protein that interacts with MglA. %%% Bacteria need to be able to move from one place to another in order to survive. One of the most intriguing, and least understood, mechanisms of bacterial motility is the phenomenon of gliding on solid substrata. The field is complicated by the likelihood that the gliding mechanisms employed by one group of gliding bacteria may not be the same as those employed by other groups. In myxobacteria, gliding is crucial not only to enable the bacteria to find food, but also to enable the bacteria to undergo a developmental transition from the vegetative gliding bacterium form to a sporogenic "fruiting body." There are two almost independent motility systems, termed "A" ("adventurous") and "S" ("social"). S-motility requires cell-to-cell proximity for movement to occur, and is known to involve at least 12 distinct genes. A-motility does not require cell-cell contact, and is controlled by at least 22 genes. Wild-type myxococci exhibit both A+ and S+ motility. A mutation in one of the A or S genes abolishes only the A or S type of motility. Both of these mechanisms seem to involve regulation of the same basic motility machinery. In addition, there are other genes, termed "frz" genes, which affect the rate at which cells reverse direction while gliding. However, there is a single genetic locus, mglA, for which a mutation abolishes both A and S type motility, resulting in totally nonmotile bacteria. The proposed studies of this pivotal gene are likely to shed new light on the mechanism of gliding in myxococci.

本项目的长期目标是了解 粘细菌表面移位或滑动的机制。 一个多样化的群体的生存环境重要 生物，包括粘细菌、噬细胞菌、蓝藻， 贝焦托阿，取决于他们的滑翔能力。 在这个项目中， 粘球菌xanthus将作为一个模型来了解滑翔 因为它的基因特征很好。 其中一个基因，mglA， 滑翔所必需的;这个项目的重点将是如何 MglA蛋白与其他运动组分相互作用。 自从mglA 是两种已知的基因鉴定的 系统，A和S，控制滑行，MglA蛋白可能会影响 A-和S-滑动基因的表达。 因此，第一个目标是 分离和表征报告基因（lacZ）插入， A-和S-运动基因，并确定它们的转录是否 在MGL-菌株中改变。 另一个目标是利用诱变 通过鉴定mglA突变体来探测MglA的功能结构域 显示了异常滑翔 抑制剂实验也被 旨在识别编码蛋白质的基因， MglA. 已经发现了一种突变体， mglA缺陷，并克隆相应的基因以确定 如果它编码一种能与MglA相互作用的滑动蛋白 %%% 细菌需要能够从一个地方移动到另一个地方， 生存 其中最有趣的，也是最不被理解的， 细菌运动的机制是滑动现象， 坚实的基质 这个领域很复杂，因为 一群滑行细菌的滑行机制 可能与其他团体所雇用的人员不同。 在 粘细菌，滑行是至关重要的，不仅使细菌能够 寻找食物，同时也使细菌能够进行 从植物性滑行细菌形式的发育转变 形成一个产孢的“子实体”。“有两个几乎独立的 运动系统，称为“A”（“冒险”）和“S”（“社会”）。 S-运动性需要细胞与细胞之间的接近才能发生运动， 并且已知涉及至少12个不同的基因。 A能动性 不需要细胞与细胞接触，并且由至少 22个基因。 野生型粘球菌表现出A+和S+运动性。 一 A或S基因中的一个突变仅废除A或S型 运动性。 这两种机制似乎都涉及监管 相同的基本运动机制 此外，还有其他 基因，称为“frz”基因，影响细胞生长的速度， 在滑行时反向。 然而，有一个单一的 基因座，mglA，突变消除A和S 型运动，导致完全不运动的细菌。 的 对这一关键基因的拟议研究可能会带来新的启示 粘球菌的滑动机制