GENETIC COMPETENCE APPARATUS OF BACILLUS SUBTILIS

描述(改编自调查人员的摘要)： 枯草芽孢杆菌能被外源DNA转化 称为能力的生理状态。有能力的细胞能够 结合双链DNA，在细胞表面碎裂DNA，以及 在细胞包膜上运输一条单链。长期的 本项目的目标是了解这些过程在 分子水平。转化所需的十几个基因，以及它们的 蛋白质产品，已经进行了表征。它们之间的相互作用 蛋白质及其在DNA结合和运输中的作用将是 通过遗传学和生物化学方法进行研究。这些措施包括 对单个蛋白质进行突变，然后寻找等位基因- 特异性抑制，用来分析蛋白质/蛋白质相互作用 表面等离子体共振、交联和免疫沉淀，以及 已知能力DNA结合的可及性的测定 突变体中不同大小的蛋白质到外源分子探针 缺乏其他能力蛋白的。改造DNA的命运将是 以缺乏已知活性蛋白的突变体为特征，并且 结合和摄取过程中转化DNA所接触的蛋白质将 使用一种新的DNA-蛋白质交联法进行表征。一个 在体外，DNA转运系统将利用膜小泡来开发。 还将分离转化所需的其他基因，并 特色化的。4型Pilin样Comg蛋白的可能性 还将研究与细胞壁的相互作用和重新塑造细胞壁，因为 ComGA蛋白是否会对复制和分离产生影响 有能力的细胞中的染色体。

DESCRIPTION (adapted from the investigator's abstract): Bacillus subtilis can be transformed by exogenous DNA when in a physiological state known as competence. Competent cells are able to bind double-stranded DNA, fragment the DNA on the cell surface, and transport a single strand across the cell envelope. The long-term objective of this project is to understand these processes on the molecular level. A dozen genes required for transformation, and their protein products, have been characterized. The interactions among these proteins and their roles in DNA binding and transport will be investigated by genetic and biochemical methods. These will include mutagenesis of individual proteins followed by the search for allele- specific suppression, the analysis of protein/protein interactions using surface plasmon resonance, cross-linking and immunoprecipitation, and determination of the accessibility of a known competence DNA binding protein to exogenous molecular probes of varying sizes in mutants lacking other competence proteins. The fate of transforming DNA will be characterized in mutants lacking known competence proteins, and the proteins contacted by transforming DNA during binding and uptake will be characterized using a novel DNA-protein cross-linking approach. An in vitro DNA transport system will be developed using membrane vesicles. Additional genes required for transformation will also be isolated and characterized. The possibility that the type 4 pilin-like ComG proteins interact with and remodel the cell wall will also be investigated, as will the effect of the ComGA protein on replication and segregation of chromosomes in competent cells.