Photoactivatable antisense DNA: suppression of ampicillin resistance in normally resistant Escherichia coli.
Antisense oligodeoxyribonucleotides complementary to a segment of the beta-lactamase gene and containing psoralen monoadducts at specific sites were examined for their ability to make normally resistant bacteria sensitive to ampicillin. Irradiation of oligonucleotides and psoralens with long-wavelength ultraviolet radiation (380-400 nm) produced monoadducted antisense molecules. High-performance liquid chromatography was used to purify microgram quantities of photoactivatable antisense DNA. Escherichia coli transformed with a plasmid containing the gene for beta-lactamase were used to test a series of oligonucleotides containing psoralen monoadducts after additional exposure to the photoactivating effects of long-wavelength ultraviolet radiation (320-400 nm). Normally resistant bacteria treated with this photoactivatable form of antisense DNA (0.4 microM) were specifically sensitized to ampicillin. The reduction in colony formation ranged from 31 to 79% in comparison to control oligonucleotides which did not contain photoactivatable monoadduct moieties. Bacteria treated in a similar manner but in the presence of tetracycline instead of ampicillin were not affected. The activity of beta-galactosidase, whose gene is located on the same plasmid as beta-lactamase, was not affected.
Gasparro
F P
FP
Department of Dermatology, Yale University, New Haven, CT 06510.
Edelson
R L
RL
O'Malley
M E
ME
Ugent
S J
SJ
Wong
H H
HH
D000668:Ampicillin Resistance / Q000235:genetics*; D001483:Base Sequence; D016373:DNA, Antisense; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D008730:Methoxsalen / Q000494:pharmacology*; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000494:pharmacology* / Q000528:radiation effects; D010957:Plasmids; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology; D013489:Suppression, Genetic; D014307:Trioxsalen / Q000031:analogs & derivatives* / Q000494:pharmacology; D014466:Ultraviolet Rays; D001618:beta-Lactamases / Q000235:genetics*
D016373:DNA, Antisense; D016376:Oligonucleotides, Antisense; D011838:Radiation-Sensitizing Agents; C018822:aminomethyltrioxsalen; D001618:beta-Lactamases; D008730:Methoxsalen; D014307:Trioxsalen