CAREER: Mechanisms of defense and counter-defense in the battle between bacteria and their viruses

职业：细菌和病毒战斗中的防御和反防御机制

基本信息

批准号：
2054755
负责人：
Asma Hatoum
金额：
$ 89.03万
依托单位：
University of Illinois at Urbana-Champaign
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-16 至 2023-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2054755&HistoricalAwards=false
关键词：
CAREER Mechanisms defense counter battle

项目摘要

Bacteria and bacteriophages (bacterial viruses) have evolved a sophisticated arsenal of defensive and offensive molecular weaponry targeted against each other. Phages are ten times more abundant than their bacterial hosts in every environment tested, and thus they profoundly impact the bacterial communities in all environments. Although much research is currently focused on investigating bacterial defense systems in isolation, research activities in this project will examine whether bacterial immune systems act with other cellular processes to maximize the efficiency of defense. In this project, Staphylococcus bacteria and their phages, both abundant residents of human skin, will be used as a model host-virus system. Educational activities designed to stimulate interest in science will provide hands-on research experiences to undergraduates and high school students through a phage discovery course. Undergraduates will also gain early exposure to cutting-edge genome editing tools and techniques. The research has the potential to inspire novel biotechnologies and the educational activities are expected to promote participation of underrepresented groups in STEM careers.The overarching goal of this project is to gain fundamental insight into defense and counter-defense mechanisms in S. epidermidis and its phages as a model system. CRISPR-Cas are an important class of adaptive defense systems that use small RNAs and Cas nucleases to destroy invading phages. Many staphylococci naturally possess Type III (CRISPR-Cas10) systems, which are among the most widespread in nature. Although recent research has shed light on the canonical immunity pathway of the model CRISPR-Cas10 system in S. epidermidis, the question of whether or not CRISPR-Cas10 relies upon other (non-Cas) pathways to carry out defense was never posed. Preliminary work in the PIs lab has discovered unexpected interactions between CRISPR-Cas10 and two conserved cellular pathways previously considered unrelated to immunity. These observations support the central hypothesis that CRISPR-Cas10 integrates with other cellular pathways, including other immune systems in S. epidermidis, to carry out defense. This integration in turn impacts the corresponding phage-encoded mechanisms of counter-defense. Research in this project will test this hypothesis by using a combination of biochemistry, genetic, and molecular biology approaches to 1) characterize molecular interactions between CRISPR-Cas10 and other cellular pathways, 2) determine the molecular mechanisms by which newly discovered immune system(s) operate, and 3) characterize phage-encoded mechanisms that counter these defenses. The new insights gained by this research are expected to form the basis for biotechnologies that can be used to shape and control natural Staphylococcus communities.

细菌和噬菌体（细菌病毒）已经进化出一套复杂的防御性和进攻性分子武器库，可以相互攻击。在每个测试环境中，噬菌体的数量都比其细菌宿主丰富十倍，因此它们对所有环境中的细菌群落都有深远的影响。尽管目前许多研究都集中在单独研究细菌防御系统，但该项目的研究活动将检查细菌免疫系统是否与其他细胞过程相互作用，以最大限度地提高防御效率。在该项目中，人类皮肤中大量存在的葡萄球菌及其噬菌体将被用作模型宿主病毒系统。旨在激发科学兴趣的教育活动将通过噬菌体发现课程为本科生和高中生提供实践研究经验。本科生还将尽早接触尖端的基因组编辑工具和技术。该研究有潜力激发新型生物技术，教育活动预计将促进代表性不足的群体参与 STEM 职业。该项目的首要目标是深入了解表皮葡萄球菌及其噬菌体的防御和反防御机制作为模型系统。 CRISPR-Cas 是一类重要的适应性防御系统，它使用小 RNA 和 Cas 核酸酶来摧毁入侵的噬菌体。许多葡萄球菌天然具有 III 型 (CRISPR-Cas10) 系统，这是自然界中最广泛存在的系统之一。尽管最近的研究揭示了表皮葡萄球菌中模型 CRISPR-Cas10 系统的经典免疫途径，但从未提出 CRISPR-Cas10 是否依赖其他（非 Cas）途径来进行防御的问题。 PI 实验室的初步工作发现 CRISPR-Cas10 与之前被认为与免疫无关的两条保守细胞途径之间存在意想不到的相互作用。这些观察结果支持了核心假设，即 CRISPR-Cas10 与其他细胞途径（包括表皮葡萄球菌中的其他免疫系统）整合以进行防御。这种整合反过来又影响相应的噬菌体编码的反防御机制。该项目的研究将结合使用生物化学、遗传和分子生物学方法来检验这一假设：1) 表征 CRISPR-Cas10 与其他细胞途径之间的分子相互作用，2) 确定新发现的免疫系统的分子机制。）操作，3）表征对抗这些防御的噬菌体编码机制。这项研究获得的新见解预计将成为可用于塑造和控制天然葡萄球菌群落的生物技术的基础。