Reassembling a cannon in the DNA defense arsenal: Genetics of StySA, a BREX phage exclusion system in Salmonella lab strains.

ABSTRACT: Understanding mechanisms that shape horizontal exchange in prokaryotes is a key problem in biology. A major limit on DNA entry is imposed by restriction-modification (RM) processes that depend on the pattern of DNA modification at host-specified sites. In classical RM, endonucleolytic DNA cleavage follows detection of unprotected sites on entering DNA. Recent investigation has uncovered BREX (BacteRiophage EXclusion) systems. These RM-like activities employ host protection by DNA modification, but immediate replication arrest occurs without evident of nuclease action on unmodified phage DNA. Here we show that the historical stySA RM locus of Salmonella enterica sv Typhimurium is a variant BREX system. A laboratory strain disabled for both the restriction and methylation activity of StySA n

SUBMITTER: Zaworski J 

PROVIDER: S-EPMC9009780 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature