Impact of DNA gyrase inhibition by antisense ribozymes on rec A in E. coli.
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.
Shilpakala
Sainath Rao
SR
Department of Genetics, Dr ALMPG Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India. shilpa_ibms@yahoo.com
Raghunathan
Malathi
M
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
D016372:RNA, Antisense; D016337:RNA, Catalytic; D059005:Topoisomerase II Inhibitors; D011938:Rec A Recombinases