title: Impact of DNA gyrase inhibition by antisense ribozymes on rec A in E. coli.
abstract: The chromosome of E. coli is maintained in a negatively supercoiled state, and supercoiling levels are affected by growth phase and a variety of environmental stimuli. Regulation of DNA supercoiling yields a complex spectrum of effects on the E. coli recA system. Previous studies indicated that inhibition of DNA gyrase by antibiotics that act on the DNA gyrase A subunit results in turning on the recA system. Here we show that antisense ribozymes that act on the DNA gyrase A subunit can also induce recA. We used real time PCR and immunoblot to analyze the impact of DNA gyrase A inhibition by antisense ribozymes on recA expression. When gyrase A was inhibited by the RNase P mediated antisense ribozymes the expression of recA was induced around 130-fold as seen by real time PCR analysis. This suggests that repair pathway is induced by antisense ribozymes against DNA gyrase A and the damage produced by these ribozymes may be similar to that produced by fluoroquinolones.
authors.affiliation: Department of Genetics, Dr ALMPG Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India. shilpa_ibms@yahoo.com
authors.forename: Sainath Rao
authors.initials: SR
authors.lastname: Shilpakala
authors.forename: Malathi
authors.initials: M
authors.lastname: Raghunathan
mesh_terms: D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D015151:Immunoblotting; D016372:RNA, Antisense / Q000378:metabolism*; D016337:RNA, Catalytic / Q000378:metabolism*; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D059005:Topoisomerase II Inhibitors
chemical_list: D016372:RNA, Antisense; D016337:RNA, Catalytic; D059005:Topoisomerase II Inhibitors; D011938:Rec A Recombinases