Title | Inhibition of gene expression in Escherichia coli by antisense phosphorodiamidate morpholino oligomers. |
Publication Type | Journal Article |
Year of Publication | 2003 |
Authors | Geller, BL, Deere, JD, Stein, DA, Kroeker, AD, Moulton, HM, Iversen, PL |
Journal | Antimicrobial agents and chemotherapy |
Volume | 47 |
Issue | 10 |
Pagination | 3233-9 |
Date Published | 2003 Oct |
Keywords | 16S, Ribosomal, RNA |
Abstract | Antisense phosphorodiamidate morpholino oligomers (PMOs) were tested for the ability to inhibit gene expression in Escherichia coli. PMOs targeted to either a myc-luciferase reporter gene product or 16S rRNA did not inhibit luciferase expression or growth. However, in a strain with defective lipopolysaccharide (lpxA mutant), which has a leaky outer membrane, PMOs targeted to the myc-luciferase or acyl carrier protein (acpP) mRNA significantly inhibited their targets in a dose-dependent response. A significant improvement was made by covalently joining the peptide (KFF)(3)KC to the end of PMOs. In strains with an intact outer membrane, (KFF)(3)KC-myc PMO inhibited luciferase expression by 63%. A second (KFF)(3)KC-PMO conjugate targeted to lacI mRNA induced beta-galactosidase in a dose-dependent response. The end of the PMO to which (KFF)(3)KC is attached affected the efficiency of target inhibition but in various ways depending on the PMO. Another peptide-lacI PMO conjugate was synthesized with the cationic peptide CRRRQRRKKR and was found not to induce beta-galactosidase. We conclude that the outer membrane of E. coli inhibits entry of PMOs and that (KFF)(3)KC-PMO conjugates are transported across both membranes and specifically inhibit expression of their genetic targets. |