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Defining CRISPR adaptation and interference mechanisms in E. coli

定义大肠杆菌中的 CRISPR 适应和干扰机制

基本信息

批准号：
10387608
负责人：
Dipali Gurudutt Sashital
金额：
$ 2.4万
依托单位：
IOWA STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-06-01 至 2022-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10387608
关键词：
Adaptive Immune System Affect Antibiotic Resistance Archaea Automobile Driving Bacteria Bacteriophages Base Pairing Binding Binding Proteins Biochemical Biophysics CRISPR interference Clustered Regularly Interspaced Short Palindromic Repeats Communities Complex DNA Dependence Detection Development Disease Ecosystem Effectiveness Elements Escherichia coli Event Evolution Genes Genetic Genome Goals Guide RNA Health Horizontal Gene Transfer Human Human Microbiome Immune Immune response Immune system Immunity Infection Invaded Investigation Knowledge Lead Life Measures Metabolism Methods Modeling Molecular Molecular Conformation Movement Mutation Nucleic Acids Organism Plasmids Point Mutation Population Population Dynamics Production Proteins RNA Interference Race Seeds Shapes Small RNA Specificity Structure System Therapeutic Time Virus Diseases Work antimicrobial arm biophysical tools combat endonuclease in vivo microbiome mutant pathogenic virus response tool viral resistance virus host interaction

项目摘要

Project Summary Viral resistance is essential in all kingdoms of life, although diverse organisms have evolved equally diverse mechanisms for combatting infection. In bacteria and archaea, the CRISPR (clustered regularly interspaced short palindromic repeats) adaptive immune system clears invading DNA during infection through a small-RNA guided interference mechanism. CRISPR immunity proceeds through two stages: adaptation, in which fragments of invasive DNA from bacteriophages or plasmids are inserted as spacers within the CRISPR locus of the host genome and subsequently serve as templates for the production of small guide CRISPR (cr)RNAs;; and interference, during which the crRNA and its effector CRISPR associated (Cas) proteins bind complementary target regions of the invading DNA, leading to its destruction by a Cas endonuclease. Our goal is to define how bacteria maximize their immune capacity to gain an advantage in the molecular arms race against their invaders. Our first goal is to understand the sequence-dependence of immune system evasion through the development of point mutations within the invading DNA. Our previous studies have revealed that spacer sequence greatly influences the effectiveness of these “escape” mutations, suggesting for the first time that some spacer sequences provide stronger immunity than others. In addition, we have discovered that during initial infection, bacteria use a two-tiered defensive system to broaden their adaptation capacity. We will evaluate the impact of this tactic on host immunity and elucidate the molecular mechanisms underlying this defense strategy. Finally, we will determine the structural basis for rapid adaptation triggered when the CRISPR machinery senses non- canonical target sequences. Our studies will have major implications on the understanding of host-virus interactions and co-evolution, an important determinant of the compositional dynamics within complex ecological systems including the human microbiome.

项目总结