Mechanism of CTX bacteriophage integration

CTX噬菌体整合机制

• 批准号: 6906647
• 负责人: SARAH M MCLEOD
• 金额: $ 4.99万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6906647
• 关键词: DNA footprinting; Vibrio cholerae; bacterial virus; cholera toxin; chromosomes; gene expression; genetic recombination; genetic screening; nucleic acid sequence; polymerase chain reaction; recombinase; southern blotting; virus infection mechanism; virus integration

DESCRIPTION (provided by applicant): The goal of this proposal is to understand the mechanism of CTXphi integration and its relationship to chromosome dimer resolution. CTXphi_ is a filamentous bacteriophage that carries the genes for cholera toxin, the primary virulence factor of Vibrio cholerae. CTXphi integrates site-specifically into the chromosome of v. cholerae and thereby renders non-pathogenic isolates toxigenic. Unlike other characterized phages and viruses, CTXphi depends on chromosome-encoded recombinases, XerC and XerD, to integrate its DNA. Integration occurs near the chromosome mid-point in close proximity to the d/f site, which is the XerC and XerD substrate for resolution of chromosome dimers. Thus, the specific aims of this proposal include: I) definition of DNA sequences required for CTXphi integration and recombination at d/f, II) characterization of recombination by XerC and XerD in vitro; 111) identification, via a genetic screen, of additional chromosomal genes required for CTXd_ integration; and IV) characterization of the phage encoded rstB gene and examination of its effect on CTXphi integral ion. Results from these studies will broaden our understanding of CTXphi biology and the evolution of V. cholerae pathogenicity and will clarify the mechanism of a novel means of phage integration.

描述（由申请人提供）：该提案的目的是了解CTXPHI集成的机制及其与染色体二聚体分辨率的关系。 ctxphi_是一种丝状噬菌体，它带有霍乱毒素的基因，霍乱毒素是弧菌霍乱的主要毒力因子。 CTXPHI特异性地集成了v。Cholerae的染色体，从而使非致病分离株毒素造成毒素。与其他特征性的噬菌体和病毒不同，CTXPHI取决于染色体编码的重组酶XERC和XERD以整合其DNA。积分发生在染色体中点附近，靠近D/F位点，这是XERC和XERD底物，用于分辨染色体二聚体。因此，该提案的具体目的包括：i）d/f时CTXPHI整合和重组所需的DNA序列的定义，ii）XERC和XERD体外重组的表征； 111）通过遗传筛选鉴定CTXD_积分所需的其他染色体基因； iv）表征噬菌体编码的RSTB基因及其对CTXPHI积分离子的影响。这些研究的结果将扩大我们对CTXPHI生物学的理解和V.霍乱致病性的演变，并将阐明新型噬菌体整合手段的机制。