菌体抑制并逃避细菌中的cGAS类免疫功能
Erin Huiting1, Xueli Cao2, Jie Ren3
1Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA.
Cell
|February 7, 2023
概括
细菌拥有基于循环GMP-AMP合成酶 (cGAS) 的免疫系统 (CBASS),可以对抗菌体. 菌体用一种抗CBASS蛋白来对抗这种防御, 这导致了进化军备竞赛.
科学领域:
- 微生物学
- 免疫学
- 分子生物学
背景情况:
- 细胞抗病毒免疫依赖于cGAS-STING通路,合成2',3'-cGAMP.
- 细菌循环GMP-AMP合成酶 (cGAS) 类似的酶,称为CBASS,产生循环寡核酸的抗菌体活性,但内源性功能仍未得到证实.
研究的目的:
- 研究CBASS在Pseudomonas aeruginosa中的内源抗菌活性.
- 了解细菌抗菌体防御机制和菌体反防御策略.
主要方法:
- 在Pseudomonas aeruginosa中发现一种内源的cGAS类酶.
- 在菌体感染期间分析循环核酸合成 (3',3'-cGAMP).
- 反CBASS蛋白 (Acb2) 的表征及其与循环核酸和效应物的相互作用.
- 通过基因突变评估菌体逃避策略.
主要成果:
- 在菌体感染时,P. aeruginosa中的内源cGAS类酶产生3',3'-cGAMP,激活菌体效应剂以限制菌体复制.
- 菌体进化了Acb2,一种通过结合3',3'-cGAMP和其他循环核酸,包括哺乳动物cGAS产物来抑制酸酶活性的抗CBASS蛋白.
- CBASS有效地阻断了菌体的复制和 lysogenic 诱导,但菌体可以通过主要囊基因的突变来逃避这种防御.
结论:
- 这项研究证明了CBASS在细菌中的内源性抗菌体功能.
- CBASS采用复杂的抑制和逃避策略,突出显示了细菌和菌体之间的动态共同进化关系.
- 这些发现揭示了Acb2在物种之间对基于cGAS的免疫力的广泛抑制潜力.
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