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Nonsequence-specific inhibition of bacterial luminescence by phosphorothioate oligodeoxyribonucleotides
L A Chrisey1, M Pazirandeh, H S Liss
1Naval Research Laboratory, Washington, DC 20375-5348, USA.
Abstract:
To evaluate the effect of synthetic DNA oligomers on regulation of bacterial genes in vivo, we tested 63 oligomers of variable length and chemistry for their ability to selectively suppress light production in the bioluminescent marine organism, Vibrio fischeri. Phosphodiester, phosphorothioate, and mixed backbone oligomers were designed to be lux gene targeted or nontargeted (negative) controls. Although significant suppression of luminescence was observed, most notably with the phosphorothioate oligomers, there was no correlation between inhibitory activity and oligomer sequence. The phosphorothioate oligomer that was most potent for inhibition of luminescence in bacterial culture had no effect on the activity of purified luciferase. Mechanisms other than sequence-specific inhibition of gene expression or direct interaction with luciferase are discussed.
Insights
Synthetic DNA oligomers showed potential for regulating bacterial genes in vivo. However, luminescence suppression in Vibrio fischeri was not sequence-specific, suggesting alternative regulatory mechanisms.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Synthetic DNA oligomers are explored for gene regulation.
- Bacterial bioluminescence in Vibrio fischeri serves as a model system.
- Understanding gene regulation mechanisms is crucial for biological research.
Purpose of the Study:
- To assess the efficacy of synthetic DNA oligomers in regulating bacterial genes in vivo.
- To investigate the sequence-specific effects of different oligomer chemistries on gene expression.
- To identify potential mechanisms of action for DNA oligomers in bacterial systems.
Main Methods:
- Tested 63 synthetic DNA oligomers (phosphodiester, phosphorothioate, mixed backbone) in Vibrio fischeri.
- Oligomers were designed as lux gene targeted or non-targeted controls.
- Assessed suppression of light production (luminescence) as a measure of gene regulation.
Main Results:
- Significant suppression of bacterial luminescence was observed with certain oligomers, particularly phosphorothioate types.
- No correlation was found between inhibitory activity and the specific sequence of the DNA oligomers.
- The most potent phosphorothioate oligomer did not inhibit purified luciferase activity, indicating a non-enzymatic mechanism.
Conclusions:
- Synthetic DNA oligomers can influence bacterial gene expression in vivo, but not through sequence-specific gene targeting.
- The observed luminescence suppression suggests alternative mechanisms of action, potentially involving non-specific interactions.
- Further research is needed to elucidate the precise mechanisms by which these oligomers regulate bacterial activity.