Inhibition of aac(6′)-Ib-mediated amikacin resistance by nuclease-resistant external guide sequences in bacteria

Inhibition of bacterial gene expression by RNase P-directed cleavage is a promising strategy for the development of antibiotics and pharmacological agents that prevent expression of antibiotic resistance. The rise in multiresistant bacteria harboring AAC(6′)-Ib has seriously limited the effectivenes...

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Autores principales: Soler Bistué, A.J.C., Martín, F.A., Vozza, N., Ha, H., Joaquín, J.C., Zorreguieta, A., Tolmasky, M.E.
Formato: Artículo publishedVersion
Publicado: 2009
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DNA
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00278424_v106_n32_p13230_SolerBistue
https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00278424_v106_n32_p13230_SolerBistue_oai
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Sumario:Inhibition of bacterial gene expression by RNase P-directed cleavage is a promising strategy for the development of antibiotics and pharmacological agents that prevent expression of antibiotic resistance. The rise in multiresistant bacteria harboring AAC(6′)-Ib has seriously limited the effectiveness of amikacin and other aminoglycosides. We have recently shown that recombinant plasmids coding for external guide sequences (EGS), short antisense oligoribonucleotides (ORN) that elicit RNase P-mediated cleavage of a target mRNA, induce inhibition of expression of aac(6′)-Ib and concomitantly induce a significant decrease in the levels of resistance to amikacin. However, since ORN are rapidly degraded by nucleases, development of a viable RNase P-based antisense technology requires the design of nuclease resistant RNA analog EGSs. We have assayed a variety of ORN analogs of which selected LNA/DNA co-oligomers elicited RNase P-mediated cleavage of mRNA in vitro. Although we found an ideal configuration of LNA/DNA residues, there seems not to be a correlation between number of LNA substitutions and level of activity. Exogenous administration of as low as 50 nM of an LNA/DNA co-oligomer to the hyperpermeable E. coli AS19 harboring the aac(6′)-Ib inhibited growth in the presence of amikacin. Our experiments strongly suggest an RNase P-mediated mechanism in the observed antisense effect.