Antisense inhibition of RNase P: mechanistic aspects and application to live bacteria.

We explored bacterial RNase P as a drug target using antisense oligomers against the P15 loop region of Escherichia coli RNase P RNA. An RNA 14-mer, or locked nucleic acid (LNA) and peptide nucleic acid (PNA) versions thereof, disrupted local secondary structure in the catalytic core, forming hybrid duplexes over their entire length. Binding of the PNA and LNA 14-mers to RNase P RNA in vitro was essentially irreversible and even resisted denaturing PAGE.

Antisense inhibition of Escherichia coli RNase P RNA: mechanistic aspects.

The ribonucleoprotein enzyme RNase P catalyzes endonucleolytic 5'-maturation of tRNA primary transcripts in all domains of life. The indispensability of RNase P for bacterial cell growth and the large differences in structure and function between bacterial and eukaryotic RNase P enzymes comply with the basic requirements for a bacterial enzyme to be suitable as a potential novel drug target. We have identified RNA oligonucleotides that start to show an inhibitory effect on bacterial RNase P RNAs of the structural type A (for example, the Escherichia coli or Klebsiella pneumoniae enzymes) at subnanomolar concentrations in our in vitro precursor tRNA (ptRNA) processing assay.

Evaluation of bacterial RNase P RNA as a drug target.

RNA has gained increasing importance as a therapeutic target. However, so far mRNAs rather than stable cellular RNAs have been considered in such studies. In bacteria, the tRNA-processing enzyme RNase P has a catalytic RNA subunit.