CRISPR-Cas系统利用病毒DNA注射来建立和维持适应性免疫力
Joshua W Modell1, Wenyan Jiang1, Luciano A Marraffini1
1Laboratory of Bacteriology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
Nature
|March 30, 2017
概括
在感染过程中,集群定期间隔的短平行列重复 (CRISPR) - Cas 系统从入侵的菌体中获得新的DNA间隔器. 这种及时获取,特别是从早期注射的DNA中获取,增强了细菌对病毒威胁的免疫力.
科学领域:
- 微生物学
- 分子生物学
- 免疫学
背景情况:
- CRISPR-Cas系统是使用间隔序列来识别和消除入侵的核酸的原生细胞免疫机制.
- 隔离器获取是CRISPR免疫的一个关键步骤,它涉及将外来DNA片段集成到宿主CRISPR位点中.
- 在病毒感染期间获得间隔器的时间和特定的基因组位置在很大程度上仍然没有特征.
研究的目的:
- 在细菌菌感染期间调查黄金葡萄球体间隔器的时间动态.
- 确定病毒生命周期的哪些阶段对间隔器的获取负责.
- 评估间隔器获取位置对CRISPR-Cas9免疫力的影响.
主要方法:
- 使用葡萄球菌菌体φ12的CRISPR-Cas9系统感染金黄色葡萄球菌株.
- 使用突变菌体和注射DNA的分析来追踪新的间隔器.
- 根据所获得的间隔剂的来源评估CRISPR-Cas9介导的免疫力.
主要成果:
- 在菌体感染后立即发生间隔器的获取,最好从注射的病毒DNA的cos部位.
- 大多数间隔剂是在DNA注射阶段获得的,而不是在复制或包装过程中.
- 从早期注射的基因组区域获得的隔离剂与晚期注射的区域相比具有更高的免疫力.
结论:
- 在菌体感染周期的早期,CRISPR-Cas系统战略性地获取间隔器,以最大限度地提高免疫反应的有效性.
- 间隔器获取的时间和位置对于优化CRISPR介导的细菌对菌体的防御至关重要.
- 了解菌体生命周期和CRISPR免疫力之间的相互作用,可以了解 prokaryotic 防御策略.
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