Expression dynamics of the CfrBI restriction-modification system in single cells and theimpact on restriction of phage infection for the bacterial population

CfrBI限制性修饰系统在单细胞中的表达动态及其对噬菌体感染限制对细菌群体的影响

• 批准号: 440930027
• 负责人: Dr. Johannes Gibhardt
• 金额: --
• 依托单位: Fachgebiet Molekulare Mikrobiologie (190 h)
• 依托单位国家: 德国
• 项目类别: WBP Fellowship
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/440930027?language=en
• 关键词: Expression; dynamics; CfrBI; restriction; modification

Multiple drug-resistant bacteria are an increasing problem for modern health care institutions. It is therefore deemed necessary to facilitate the research in novel approaches to combat pathogenic bacteria. Bacteriophages are bacteria-specific viruses and a promising tool due to their high host-specificity and efficiency to lyse bacterial cells. However, bacteria can also acquire resistances against phages and phages can overcome bacterial resistances. Studies are needed to deepen our understanding of the co-evolutionary processes and mechanisms of phage resistance. One of the most widespread and mobile mechanisms bacteria use to combat infections by phages are plasmid-encoded restriction modification (R-M) systems. These systems recognize a specific DNA sequence and consist of a methyltransferase (MT) and a restriction endonuclease (RE) that, upon binding to the recognition sequence, methylate or cleave the DNA, respectively. Methylation leads to resistance of the DNA against the corresponding RE. During the acquisition of such a plasmid-based R-M system, the timely orchestrated expression of the MT- and RE-encoding genes is key to establish protection and to prevent modification of virus DNA that would render the system non-functional, leading to the production of resistant phage progenies that would threaten the survival of the whole bacterial population. While progress has been made in the study of the regulatory mechanism of R-M systems in vitro, little is known about the regulatory dynamics in vivo. The following proposal aims to increase our understanding about the regulation of R-M systems in vivo, their dynamics during their establishment in single cells, involved factors and the consequences for their protective function of bacterial cells and populations. Eventually, the gain in knowledge will help to progress our understanding of the interaction and co-evolution of bacteria and phages and the prospect of phage therapy for bacterial infections.

多重耐药细菌是现代医疗机构面临的一个日益严重的问题。因此，有必要促进对抗病原菌的新方法的研究。噬菌体是细菌特异性病毒，由于其高度宿主特异性和裂解细菌细胞的效率，是一种很有前途的工具。然而，细菌也可以获得针对噬菌体的抗性，并且噬菌体可以克服细菌的抗性。需要进行研究来加深我们对噬菌体抗性的共同进化过程和机制的理解。细菌用来对抗噬菌体感染的最广泛和最灵活的机制之一是质粒编码的限制性修饰（R-M）系统。这些系统识别特定的 DNA 序列，由甲基转移酶 (MT) 和限制性内切酶 (RE) 组成，在与识别序列结合后，分别甲基化或切割 DNA。甲基化导致 DNA 对相应 RE 产生抗性。在获得这种基于质粒的 R-M 系统的过程中，MT 和 RE 编码基因的及时协调表达是建立保护和防止病毒 DNA 修饰的关键，病毒 DNA 修饰会使系统无法发挥作用，从而导致抗性噬菌体后代的产生，从而威胁整个细菌群体的生存。虽然 R-M 系统体外调节机制的研究取得了进展，但对体内调节动力学知之甚少。以下提案旨在加深我们对 R-M 系统体内调节、其在单细胞中建立过程中的动态、相关因素及其对细菌细胞和群体保护功能的影响的理解。最终，知识的获得将有助于加深我们对细菌和噬菌体的相互作用和共同进化的理解，以及噬菌体治疗细菌感染的前景。