A noncanonical intrinsic terminator in the HicAB toxin-antitoxin operon promotes the transmission of conjugative antibiotic resistance plasmids.

ABSTRACT: Conjugative plasmids, major vehicles for the spread of antibiotic resistance genes, often contain multiple toxin-antitoxin (TA) systems. However, the physiological functions of TA systems remain obscure. By studying two TA families commonly found on colistin-resistant IncI2 mcr-1-bearing plasmids, we discovered that the HicAB TA, rather than the StbDE TA, acts as a crucial addiction module to increase horizontal plasmid-plasmid competition. In contrast to the canonical type II TA systems in which the TA genes are cotranscribed and/or the antitoxin gene has an additional promoter to allow for an increased antitoxin/toxin ratio, the HicAB TA system with the toxin gene preceding the antitoxin gene employs internal transcription termination to allow for a higher toxin production. This intrinsi

SUBMITTER: Lin J 

PROVIDER: S-EPMC11878559 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature