ANTISENSE INHIBITION OF GENE-EXPRESSION IN BACTERIA BY PNA TARGETED TO MESSENGER-RNA

Peptide nucleic acid (PNA) is a DNA mimic with attractive properties f or developing improved gene-targeted antisense agents. To test this po tential of PNA in bacteria, PNAs were designed to target the start cod on regions of the Escherichia coli beta-galactosidase and beta-lactama se genes. Dose-dependent and specific gene inhibition was observed in vitro using low nanomolar PNA concentrations and in vivo using low mic romolar concentrations. Inhibition was more efficient for a permeable E. coli strain relative to wild-type K-12. The potency of the anti-bet a-lactamase PNAs was abolished by a six base substitution, and inhibit ion could be re-established using a PNA with compensating base changes . Antisense inhibition of the beta-lactamase gene was sufficient to se nsitize resistant cells to the antibiotic ampicillin. The results demo nstrate gene-and sequence-specific antisense inhibition in E. coli and open possibilities for antisense antibacterial drugs and gene functio n analyses in bacteria.