Distributive Conjugal Transfer: a New Paradigm and Benchmark for Bacterial Horizontal Gene Transfer

分配性配偶转移：细菌水平基因转移的新范式和基准

• 批准号: 1614178
• 负责人: Keith Derbyshire
• 金额: $ 66万
• 依托单位: Health Research Incorporated/New York State Department of Health
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2020-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1614178&HistoricalAwards=false
• 关键词: Distributive; Conjugal; Transfer; New; Paradigm

The transfer of DNA from one bacterium to another accelerates the evolution of new strains and species. On the negative side, DNA transfer could facilitate the spread of antibiotic resistance genes, complicating infectious disease treatment strategies. On the positive side, DNA transfer could also create bacterial strains with improved beneficial properties, such as the remediation of petroleum-contaminated soil. Mycobacteria are a branch of the bacterial kingdom that includes both pathogens and brownfield soil-dwelling species. A novel kind of highly effective DNA transfer process, in which two cells appear to swap DNA fragments along the whole chromosome, has been described for a common laboratory mycobacterial species. The current project will identify the genes involved in that process, also testing whether distantly related mycobacteria can partake in such a transfer. The project will provide opportunities for undergraduate students and local high school teachers to gain experience in research.Conjugal DNA transfer has been described in Mycobacterium smegmatis, generating transconjugant genomes that are mixtures of the parental strains. Distributive Conjugal Transfer (DCT) differs from traditional plasmid-based conjugation systems both in creating mosaic genomes and in mechanism, and proteins usually found in plasmid transfer systems are absent from mycobacteria. A mating identity locus (mid), which determines donor or recipient activity, has been mapped to a six-gene cluster embedded within a 25-gene locus that encodes the ESX-1 secretion apparatus. The six genes comprising mid will be analyzed for their contribution to establishing mating identity, their functional association with ESX-1 secretion, and their impact on transcriptional pathways that respond to co-culture with a mating partner. DCT will also be tested in other isolates of M. smegmatis, and in other mycobacterial species. Genome sequencing of new isolates will provide comparative data for identifying the mosaicism that is a hallmark of DCT, and provide reference sequences for transconjugants generated in the laboratory. Successful implementation of this objective will provide a broader view of the impact of DCT on gene flow in the Mycobacterium genus, and provide additional genotype/phenotype information for the critical genes of the mid locus.

DNA从一种细菌转移到另一种细菌，加速了新菌株和新物种的进化。从消极的方面来说，DNA转移可能会促进抗生素耐药性基因的传播，使传染病治疗策略变得复杂。从积极的方面来看，DNA转移还可以创造出具有改进的有益特性的细菌菌株，例如修复石油污染的土壤。分枝杆菌是细菌界的一个分支，包括病原体和布朗菲尔德土壤居住物种。一种新型的高效DNA转移过程，其中两个细胞似乎沿着整个染色体沿着交换DNA片段，已经被描述为一种常见的实验室分枝杆菌物种。目前的项目将确定参与这一过程的基因，并测试远亲分枝杆菌是否可以参与这种转移。该项目将为本科生和当地高中教师提供获得研究经验的机会。在耻垢分枝杆菌中描述了接合DNA转移，产生的接合子基因组是亲本菌株的混合物。分配接合转移（DCT）与传统的基于质粒的接合系统在产生嵌合基因组和机制上都不同，并且通常在质粒转移系统中发现的蛋白质在分枝杆菌中不存在。一个交配身份基因座（中），决定供体或受体的活动，已被映射到一个6基因簇嵌入在一个25基因位点编码的ESX-1分泌装置。将分析构成mid的六个基因对建立交配身份的贡献、其与ESX-1分泌的功能关联以及其对响应与交配伴侣共培养的转录途径的影响。DCT也将在其他M分离株中进行检测。耻垢病和其他分枝杆菌物种。新分离株的基因组测序将提供比较数据，以确定镶嵌是DCT的标志，并提供参考序列的transconjugants在实验室中产生的。这一目标的成功实施将提供一个更广泛的观点DCT的影响，在分枝杆菌属的基因流，并提供额外的基因型/表型的关键基因的中间位点的信息。