细菌的逆子编码为菌体防御的三方毒素-抗毒素系统
Jacob Bobonis1,2, Karin Mitosch1, André Mateus1,3
1Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
Nature
|July 19, 2022
概括
逆子是原生生物的遗传元素. 研究人员发现Salmonella Typhimurium中的Retron-Sen2系统编码一种毒素 (RcaT),这种毒素被自身的逆转录酶-msDNA复合物中和,从而揭示出一种新的三方毒素-抗毒素系统,用于抗菌素防御.
科学领域:
- 微生物学
- 分子生物学
- 遗传学
背景情况:
- 复原体是合成多复制单链DNA (msDNA) 的 prokaryotic 复原体.
- 尽管对msDNA生物合成进行了广泛的研究,但其精确的生物功能和生理作用仍然在很大程度上不明.
研究的目的:
- 阐明逆子元素的功能,特别是来自Salmonella enterica Typhimurium的逆子-Sen2.
- 描述新发现的毒素蛋白RcaT及其与逆转录酶和msDNA的相互作用.
- 调查逆子系统在细菌防御机制中的作用.
主要方法:
- 识别并将逆子编码的辅助毒素蛋白重新命名为RcaT.
- 通过逆转录酶-msDNA复合物的RcaT中和机制的表征.
- 毒素激活抑制结合 (TAC-TIC) 的开发和应用,用于高通量逆转基因.
- 分析菌体衍生的蛋白质作为反毒素-抗毒素系统的触发剂和阻断剂.
主要成果:
- Retron-Sen2对RcaT进行编码,RcaT是由它的逆转录酶-msDNA复合物中和的毒素,形成一个含有毒素-抗毒素的三方DNA系统.
- 反转录酶结合RcaT,而msDNA提供抗毒素活性,激活发生在msDNA生物合成中断时.
- 在TAC-TIC系统中,通过修改msDNA来激活RcaT或直接抑制RcaT的菌体蛋白,从而显示出抗菌体活性.
结论:
- RcaT逆子系统代表了三方DNA调节的毒素-抗毒素系统的新型类型.
- 这些系统的功能是流产性感染的抗菌素防御机制.
- 反转录酶-msDNA复合体既可以作为抗毒素,也可以作为菌体蛋白活性传感器,调节细菌的防御.
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