BREX system of Escherichia coli distinguishes self from non-self by methylation of a specific DNA site.

作者：Gordeeva Julia; Morozova Natalya; Sierro Nicolas; Isaev Artem; Sinkunas Tomas; Tsvetkova Ksenia; Matlashov Mikhail; Truncaite Lidija; Morgan Richard D; Ivanov Nikolai V; Siksnys Virgis; Zeng Lanying; Severinov Konstantin

来源：Nucleic Acids Research, 2018.

DOI：10.1093/nar/gky1125

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 lambda infection, induction of lambda 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.

• 单位
  New England Biolabs