Mechanisms and regulation of replication, the cell cycle, gene expression, and horizontal gene transfer in prokaryotes, focusing on Bacillus subtilis

原核生物复制、细胞周期、基因表达和水平基因转移的机制和调控，重点关注枯草芽孢杆菌

• 批准号: 10792219
• 负责人: ALAN D GROSSMAN
• 金额: $ 15.05万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2027-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10792219
• 关键词: Affect; Antibiotic Resistance; Bacillus subtilis; Bacteria; Bacterial Genome; Bacteriophages; Biological Assay; Biology; Cell Cycle; Cells; Cellular Stress; Chromosomes; DNA Damage; DNA biosynthesis; Development; Elements; Environment; Event; Evolution; Fluorescence; Gene Expression; Gene Expression Profiling; Gene Transfer; Genes; Genetic Recombination; Genome; Gram-Positive Bacteria; Growth; Horizontal Gene Transfer; Human Microbiome; Individual; Life Cycle Stages; Location; Measurement; Mediating; Metabolic; Microscopy; Mobile Genetic Elements; Organism; Phenotype; Plasmids; Population; Prevalence; Process; Prokaryotic Cells; Proteins; Regulation; Stress; Symbiosis; Virulence; Virus; Visualization; Work; biological adaptation to stress; driving force; fitness; microbial; repaired; response; single cell analysis; tool; trait

Project Summary/Abstract Horizontal gene transfer (HGT) is a driving force in microbial evolution. It is largely mediated by mobile genetic elements, including viruses, conjugative plasmids, and integrative and conjugative elements (ICEs; aka conjugative transposons), and many bacterial genomes contain several mobile genetic elements, including ICEs and temperate phages. Conjugative elements are well known agents that contribute to the spread of genes for antibiotic resistances, virulence, symbiosis, metabolic functions, and more. ICEs were first discovered because they confer some of these phenotypes. However, potential phenotypes conferred to bacteria by the vast majority of ICEs are not known. It is now clear that ICEs can confer beneficial phenotypes that extend well beyond those of some of the initially characterized ICEs, and that some of these phenotypes involve functional interactions between ICEs and bacterial viruses. It is also apparent that some ICEs, when activated, cause growth arrest of their host bacteria. Despite the prevalence and importance of ICEs, there are major deficiencies in our understanding of these elements, especially in Gram-positive bacteria. Notably, little is known about the interactions between ICEs and their host cells including with co-resident viruses, and the effects ICEs have on fitness of their bacterial hosts, especially at a mechanistic level. Furthermore, little is known about the interactions between functions encoded by ICEs and those encoded by hosts, and how these interactions influence the host range and efficiencies with which ICEs function in different species. ICEs typically reside integrated in the host genome, and the transfer functions are generally not expressed in the vast majority of cells in a population. However, a small subpopulation of cells (typically ~1% or less) contain an active ICE that is expressing genes needed for conjugation. Assays of bulk populations are often not sufficient for detecting effects on the small number of cells with an active ICE. Instead, assays and measurements of individual cells in the active subpopulation are required to determine phenotypes caused by an activated ICE. Visualization of these cells by fluorescence and time-lapse microscopy is a critical tool for these analyses. These types of single-cell analyses are also useful for monitoring gene expression and the change in the cellular location of repair and recombination proteins in response to stresses caused by mobile genetic elements, DNA damage (and other perturbations). Our work will continue to focus on the lifecycle of select ICEs, including ICEBs1 and Tn916, from Gram-positive bacteria. Visualizing events in single cells and small subpopulations will allow us to answer previously difficult or unstudied problems fundamental to the ICE lifecycle and their effects on host cells. Our expertise in chromosome dynamics, DNA replication, stress responses, and microbial development dovetails nicely with our studies of ICEs and phages, notably how these processes affect the lifecycles of mobile genetic elements and how mobile genetic elements affect these processes. Our findings should be relevant to the biology of many bacterial species, especially regarding the transfer of genes between bacteria growing in different environments, including the human microbiome.

项目摘要/摘要 水平基因转移（HGT）是微生物进化的驱动力。它主要由移动遗传介导 元素，包括病毒，共轭质粒以及综合和共轭元素（ICE；又名共轭 转座子），许多细菌基因组包含几种移动遗传元素，包括冰和温带噬菌体。 共轭元素是众所周知的药物，有助于抗生素抗性，毒力，毒力的传播。 共生，代谢功能等。首先发现了冰，因为它们赋予了其中一些表型。 然而，尚不清楚绝大多数冰的潜在表型。现在很明显冰 可以赋予有益的表型，这些表型远远超出了某些最初的冰的范围，有些是 这些表型涉及冰与细菌病毒之间的功能相互作用。还显然有些冰， 激活后，会导致其宿主细菌的生长停滞。 尽管冰的普遍性和重要性，但我们对这些要素的理解仍有主要缺陷 特别是在革兰氏阳性细菌中。值得注意的是，关于冰与宿主细胞之间的相互作用知之甚少 包括与共同居住的病毒以及ICE对细菌宿主的适应性具有的影响，尤其是在机械上 等级。此外，关于ICS编码的函数与主机编码的功能之间的相互作用知之甚少， 以及这些相互作用如何影响IC在不同物种中发挥作用的宿主范围和效率。 ICS通常驻留在宿主基因组中，并且传递函数通常在广泛的 人群中的大多数细胞。但是，细胞的小亚群（通常约1％或更少）包含活性冰 这是表达结合所需的基因。批量种群的测定通常不足以检测效果 在少量的带有活性冰的细胞上。相反，在活动中的单个细胞的测定和测量 需要亚群来确定由激活冰引起的表型。通过可视化这些细胞 荧光和延时显微镜是这些分析的关键工具。这些类型的单细胞分析也是 可用于监测基因表达和修复和重组蛋白的细胞位置的变化 对移动遗传因素，DNA损伤（和其他扰动）引起的应力的反应。 我们的工作将继续关注从革兰氏阳性 细菌。可视化单细胞和小亚群中的事件将使我们以前很难回答或 未研究的问题是冰生生物及其对宿主细胞的影响。我们在染色体方面的专业知识 动力学，DNA复制，压力反应和微生物发育与我们对IC的研究非常吻合 噬菌体，尤其是这些过程如何影响移动遗传因素的生命周期以及移动遗传元素如何 影响这些过程。我们的发现应该与许多细菌物种的生物学有关，尤其是 在包括人类微生物组在内的不同环境中生长的细菌之间的基因转移。