title: Divergently overlapping cis-encoded antisense RNA regulating toxin-antitoxin systems from E. coli: hok/sok, ldr/rdl, symE/symR.
abstract: Toxin-antitoxin (TA) systems are categorized into three classes based on the type of antitoxin. In type I TA systems, the antitoxin is a small antisense RNA that inhibits translation of small toxic proteins by binding to the corresponding mRNAs. Those type I TA systems were originally identified as plasmid stabilization modules rendering a post-segregational killing (PSK) effect on the host cells. The type I TA loci also exist on the Escherichia coli chromosome but their biological functions are less clear. Genetic organization and regulatory elements of hok/sok and ldr/rdl families are very similar and the toxins are predicted to contain a transmembrane domain, but otherwise share no detectable sequence similarity. This review will give an overview of the type I TA modules of E. coli K-12, especially hok/sok, ldr/rdl and SOS-inducible symE/symR systems, which are regulated by divergently overlapping cis-encoded antisense RNAs.
authors.affiliation: Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan. mkawano@nupals.ac.jp
authors.forename: Mitsuoki
authors.initials: M
authors.lastname: Kawano
mesh_terms: D000595:Amino Acid Sequence; D000992:Antitoxins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D002876:Chromosomes, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D015964:Gene Expression Regulation, Bacterial; D014644:Genetic Variation; D008969:Molecular Sequence Data; D005810:Multigene Family; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D038621:Regulatory Sequences, Ribonucleic Acid; D013014:SOS Response, Genetics
chemical_list: D000992:Antitoxins; D001427:Bacterial Toxins; D012329:RNA, Bacterial; D038621:Regulatory Sequences, Ribonucleic Acid; C087026:Sok antisense RNA, E coli
keywords: SOS response; noncoding RNA; post-transcriptional regulation; repetitive sequence; small RNA; small protein