Bacteriophage control of host cell DNA transactions by small ORF proteins

噬菌体通过小 ORF 蛋白控制宿主细胞 DNA 交易

• 批准号: BB/Y004426/1
• 负责人: Mark Dillingham
• 金额: $ 61.65万
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FY004426%2F1
• 关键词: Bacteriophage; control; host; cell; DNA

This research proposal is designed to help us understand how bacterial cells defend themselves from invading viruses, called bacteriophage, and how bacteriophage have evolved to overcome these "immunity systems". Bacteriophage are the most abundant biological entity on the planet. Their survival depends on an ability to invade and manipulate the bacterial host in order to steal the chemical resources and machinery they need to build and release more bacteriophage particles. Upon invading the bacterial cell, bacteriophage deploy a range of small proteins (smORFs) which bind to targets in the host cell in order to take control of their resources and evade their defence systems. Recent research has uncovered a huge diversity of these immune systems which either prevent phage infection or trigger cell suicide in the infected cells as a means to preserve the uninfected population.One such bacterial defence system is RecBCD, a large protein complex which acts as an immunity hub. It functions both to recognise and degrade bacteriophage DNA molecules and to help catalogue the DNA sequences of the invading DNA to form a memory of viral sequences that is used to counteract future infection. In order to evade RecBCD, bacteriophage make smORF proteins which bind to and inhibit RecBCD: the so-called anti-RecBCD proteins. Remarkably, in response to this challenge, bacterial cells have subsequently developed retrons; genes that produce molecules called msDNAs which are capable of sensing anti-RecBCD proteins as a indicator of viral infection and triggering suicide.This project will elucidate the mechanisms of anti-RecBCD proteins and the msDNAs which can sense them. It is driven by the broader concept that the study of smORF proteins has value beyond a purely academic interest in the inner workings of bacterial viruses. By understanding how bacteriophage manipulate and kill bacteria, as well as how bacteria defend themselves from such attack, we can better develop strategies to overcome pathogenic bacteria which cause human disease. For example, we have shown that anti-RecBCD proteins potentiate the effect of fluoroquinolones (an antibiotic) and can even restore the sensitivity of clinically-resistant strains of pathogenic bacteria. Consequently, scientists are now developing drugs that target RecBCD and related complexes.It is well-established that studying the molecular machinery which orchestrates the fight between bacteriophage and bacteria has uncovered a treasure-trove of useful molecules. These include proteins and enzymes representing some of the most important and useful tools available to molecular biologists. For example, all modern gene-editing methods are based on technologies that were discovered through the study of bacterial immunity. This precedent, and the fact that vast numbers of smORF proteins and their cellular targets remain overlooked and uncharacterised, suggests that many more valuable tools await discovery.

该研究建议旨在帮助我们了解细菌细胞如何捍卫自己免受入侵病毒的侵害，称为噬菌体，以及噬菌体如何发展以克服这些“免疫系统”。噬菌体是地球上最丰富的生物实体。它们的生存取决于能够侵入和操纵细菌宿主的能力，以窃取他们建造和释放更多噬菌体颗粒所需的化学资源和机械。入侵细菌细胞后，噬菌体部署了一系列小蛋白质（SMORF），它们与宿主细胞中的靶标结合，以控制其资源并逃避其防御系统。最近的研究发现了这些免疫系统的巨大多样性，这些系统可以防止噬菌体感染或触发感染细胞中的细胞自杀，以保留未感染的人群。一种这种细菌防御系统是RECBCD，它是一种大蛋白质复合物，可作为免疫枢纽。它具有识别和降解噬菌体DNA分子的功能，并有助于对入侵DNA的DNA序列进行分类，以形成用于抵消未来感染的病毒序列的记忆。为了逃避RECBCD，噬菌体使SMORF蛋白结合并抑制RECBCD：所谓的抗RECBCD蛋白。值得注意的是，在应对这一挑战时，细菌细胞随后开发了回发。产生称为MSDNA的分子的基因能够将抗RECBCD蛋白传感为病毒感染和触发自杀的指标。该项目将阐明抗RecBCD蛋白和MSDNA的机制。它是由更广泛的概念驱动的，即SMORF蛋白的研究具有超出细菌病毒内部功能的纯粹学术兴趣的价值。通过了解噬菌体如何操纵和杀死细菌，以及细菌如何防御这种攻击，我们可以更好地制定克服引起人类疾病的致病细菌的策略。例如，我们已经表明，抗recBCD蛋白增强了氟喹诺酮类（一种抗生素）的作用，甚至可以恢复致病细菌抗性菌株的敏感性。因此，科学家现在正在开发靶向RECBCD及相关复合物的药物。这是一个良好的，研究分子机制，该分子机械精心策划了噬菌体和细菌之间的战斗，已经发现了有用分子的宝藏。这些包括代表分子生物学家可用的一些最重要和有用的工具的蛋白质和酶。例如，所有现代基因编辑方法均基于通过细菌免疫研究发现的技术。这一先例以及大量的Smorf蛋白及其细胞靶标仍然被忽视和未表征，这一事实表明，许多更有价值的工具正在等待发现。