BREX system of Escherichia coli distinguishes self from non-self by methylation of a specific DNA site
BREX system of Escherichia coli distinguishes self from non-self by methylation of a specific DNA site
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DOI：
10.1093/nar/gky1125
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发表时间：
2019-01-10
影响因子：
14.9
通讯作者：
Severinov, Konstantin
中科院分区：
文献类型：
--
作者：
Gordeeva, Julia;Morozova, Natalya;Severinov, Konstantin
原核生物进化出许多防御噬菌体捕食的系统。除了众所周知的限制性修饰和CRISPR-Cas免疫系统之外，还存在许多表征不佳的系统。一类这样的系统，称为BREX，由一个假定的磷酸酶，甲基转移酶和四个其他蛋白质。蜡样芽孢杆菌BREX系统提供对几种不相关细菌的抗性，并导致宿主DNA中特定基序的修饰。在这里，我们研究了BREX系统从天然大肠杆菌分离物的行动。我们表明，虽然它使细胞对噬菌体感染具有抗性，但从携带BREX的细胞中诱导原噬菌体导致产生克服防御的病毒。诱导的噬菌体DNA在特定基序中含有甲基化的腺嘌呤残基。在携带BREX的细胞的基因组中发现了相同的修饰。结果首次证实，对BREX系统防御的免疫力是由表观遗传修饰提供的。
Prokaryotes evolved numerous systems that defend against predation by bacteriophages. In addition to well-known restriction-modification and CRISPR-Cas immunity systems, many poorly characterized systems exist. One class of such systems, named BREX, consists of a putative phosphatase, a methyltransferase and four other proteins. A Bacillus cereus BREX system provides resistance to several unrelated phages and leads to modification of specific motif in host DNA. Here, we study the action of BREX system from a natural Escherichia coli isolate. We show that while it makes cells resistant to phage infection, induction of prophage from cells carrying BREX leads to production of viruses that overcome the defense. The induced phage DNA contains a methylated adenine residue in a specific motif. The same modification is found in the genome of BREX-carrying cells. The results establish, for the first time, that immunity to BREX system defense is provided by an epigenetic modification.