Genetic analysis of a bacterial genetic exchange element:: The gene transfer agent of Rhodobacter capsulatus
Genetic analysis of a bacterial genetic exchange element:: The gene transfer agent of Rhodobacter capsulatus
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DOI：
10.1073/pnas.97.2.859
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发表时间：
2000-01-18
影响因子：
11.1
通讯作者：
Beatty, JT
中科院分区：
文献类型：
--
作者：
Lang, AS;Beatty, JT
一种不同寻常的遗传交换系统存在于紫色非硫细菌胶囊红杆菌中。DNA的传播是由一种名为基因转移剂(CTA)的类似噬菌体的小颗粒介导的，它将生产细胞基因组的4.5kb随机片段转移到受体细胞，在那里发生等位基因替换。本文介绍了基因克隆、分析和诱变实验的结果，结果表明，Gta类似于一种与来自不同细菌属的噬菌体相关的缺陷原噬菌体，该噬菌体已被胶囊雷氏杆菌用于遗传交换。一对细胞蛋白Cck A和CtrA似乎构成了GTA结构基因表达所需的传感器激酶/反应调节信号通路的一部分。该信号通路控制GTA基因信息的生长阶段依赖的调节，在稳定期产生最大的基因表达。我们认为GTA是一种古老的前噬菌体残基，它与细菌基因组一起进化，导致了由细菌细胞控制的基因交换过程。
An unusual system of genetic exchange exists in the purple nonsulfur bacterium Rhodobacter capsulatus. DNA transmission is mediated by a small bacteriophage-like particle called the gene transfer agent (CTA) that transfers random 4.5-kb segments of the producing cell's genome to recipient cells, where allelic replacement occurs. This paper presents the results of gene cloning, analysis, and mutagenesis experiments that show that GTA resembles a defective prophage related to bacteriophages from diverse genera of bacteria, which has been adopted by R. capsulatus for genetic exchange. A pair of cellular proteins, CckA and CtrA, appear to constitute part of a sensor kinase/response regulator signaling pathway that is required for expression of GTA structural genes. This signaling pathway controls growth-phase-dependent regulation of GTA gene messages, yielding maximal gene expression in the stationary phase. We suggest that GTA is an ancient prophage remnant that has evolved in concert: with the bacterial genome, resulting in a genetic exchange process controlled by the bacterial cell.