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: 10552390
• 负责人: ALAN D GROSSMAN
• 金额: $ 74.93万
• 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/10552390
• 关键词: Affect; Antibiotic Resistance; Bacillus subtilis; Bacteria; Bacterial Genome; Bacteriophages; Biology; Cell Cycle; Cell physiology; Cells; Cellular Stress; Chromosomes; DNA biosynthesis; Development; Elements; Environment; Event; Evolution; Frequencies; Gene Expression; Gene Transfer; Genes; Genome; Gram-Positive Bacteria; Growth; Horizontal Gene Transfer; Human Microbiome; Life Cycle Stages; Mediating; Metabolic; Mobile Genetic Elements; Phenotype; Plasmids; Population; Prevalence; Process; Prokaryotic Cells; Regulation; Selfish DNA; Skin; Symbiosis; Tetracycline Resistance; Virulence; Virus; Visualization; Work; biological adaptation to stress; driving force; fitness; interest; microbial; pathogenic bacteria; response; 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. Our recent work indicates that ICEs confer beneficial phenotypes that extend well beyond those of some of the previously characterized ICEs, and that some of these phenotypes involve functional interactions between ICEs and bacterial viruses. We are focusing on mechanisms controlling horizontal gene transfer, interactions between mobile genetic elements and their host cells, and the interplay between different mobile elements found in the same cell. Many of our studies are initiated in the bacterium Bacillus subtilis. It is easy to grow and manipulate, naturally contains a variety of mobile elements, including one ICE (ICEBs1) and one functional (SPß) and two defective (PBSX, skin) temperate phages, together comprising almost 6% of the genome. Our recent work indicates that there are beneficial phenotypes conferred by ICEBs1 to host cells that extend well beyond those conferred by previously characterized ICEs, including effects on the timing of sporulation and the activity of other resident elements. 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. Furthermore, little is known about the interactions between functions encoded by ICEs and those encoded by hosts, and how these interactions influence and determine the host range and efficiencies with which ICEs function in different species. Our work will continue to focus on the lifecycle of ICEBs1 and Tn916, an ICE that is naturally found in several bacterial pathogens and is involved in the spread of tetracycline resistance between them. The ability to experimentally induce ICEBs1 in ~25- 90% of cells in a population, to achieve relatively high conjugation frequencies, and to visualize events in single cells has allowed us to answer previously difficult or unstudied problems fundamental to the ICE lifecycle. 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. We plan to pursue these interests, with particular focus on the connections between ICEs, phages, and cellular 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.

项目概要/摘要 水平基因转移（HGT）是微生物进化的驱动力，主要由移动遗传介导。 元件，包括病毒、接合质粒以及整合和接合元件（ICE；又名接合元件） 转座子），许多细菌基因组含有多种可移动遗传元件，包括 ICE 和温带噬菌体。 接合元件是众所周知的试剂，有助于抗生素抗性、毒力、 共生、代谢功能等首次被发现是因为它们赋予了其中一些表型。 然而，我们最近的工作尚不清楚绝大多数 ICE 赋予细菌的潜在表型。 表明 ICE 有益的表型远远超出了之前描述的一些表型 ICE，其中一些表型涉及 ICE 和细菌病毒之间的功能相互作用。 我们专注于控制水平基因转移的机制、移动遗传元件之间的相互作用 及其宿主细胞，以及同一细胞中不同移动元件之间的相互作用。 源自枯草芽孢杆菌，它易于生长和操作，天然含有多种活性物质。 元素，包括一种 ICE (ICEBs1) 和一种功能性 (SPß) 和两种缺陷型 (PBSX、皮肤) 温带噬菌体， 我们最近的研究表明，这些基因共同构成了基因组的近 6%。 ICEBs1 对宿主细胞的影响远远超出了先前表征的 ICE 所赋予的范围，包括对 孢子形成的时间和其他常驻元素的活动。 尽管 ICE 很普遍且很重要，但我们对这些要素的理解仍存在重大缺陷， 尤其是在革兰氏阳性细菌中，人们对 ICE 与其宿主细胞之间的相互作用知之甚少。 包括共存病毒，以及 ICE 对细菌宿主健康的影响。 了解 ICE 编码的功能与主机编码的功能之间的相互作用，以及这些相互作用如何 我们的工作将影响和确定 ICE 在不同物种中发挥作用的宿主范围和效率。 继续关注 ICEBs1 和 Tn916 的生命周期，这是一种天然存在于多种细菌病原体中的 ICE， 参与四环素耐药性在它们之间的传播，在~25-中实验诱导ICEBs1的能力。 群体中 90% 的细胞，为了实现相对较高的接合频率，并可视化单个细胞中的事件， 使我们能够回答以前困难或未研究过的 ICE 生命周期的基本问题。 染色体动力学、DNA 复制、应激反应和微生物发育与我们的研究非常吻合 ICE和噬菌体，特别是这些过程如何影响移动遗传元件的生命周期以及移动遗传元件如何 我们计划追求这些利益，特别关注 ICE 之间的联系， 我们的发现应该与许多细菌物种的生物学相关，尤其是。 关于生长在不同环境（包括人类微生物组）的细菌之间的基因转移。