Antisense inhibition of gene expression in bacteria by PNA targeted to mRNA.
Peptide nucleic acid (PNA) is a DNA mimic with attractive properties for developing improved gene-targeted antisense agents. To test this potential of PNA in bacteria, PNAs were designed to target the start codon regions of the Escherichia coli beta-galactosidase and beta-lactamase genes. Dose-dependent and specific gene inhibition was observed in vitro using low nanomolar PNA concentrations and in vivo using low micromolar concentrations. Inhibition was more efficient for a permeable E. coli strain relative to wild-type K-12. The potency of the anti-beta-lactamase PNAs was abolished by a six base substitution, and inhibition could be re-established using a PNA with compensating base changes. Antisense inhibition of the beta-lactamase gene was sufficient to sensitize resistant cells to the antibiotic ampicillin. The results demonstrate gene- and sequence-specific antisense inhibition in E. coli and open possibilities for antisense antibacterial drugs and gene function analyses in bacteria.
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Department of Biochemistry B, Panum Institute, University of Copenhagen, Denmark.
Nielsen
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D000667:Ampicillin / Q000494:pharmacology; D000668:Ampicillin Resistance / Q000235:genetics; D018387:Codon, Initiator; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D009696:Nucleic Acids / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology*; D012333:RNA, Messenger / Q000187:drug effects*; D001616:beta-Galactosidase / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics
D018387:Codon, Initiator; D009696:Nucleic Acids; D010455:Peptides; D012333:RNA, Messenger; D000667:Ampicillin; D001616:beta-Galactosidase; D001618:beta-Lactamases