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Doxycycline inhibits pre-rRNA processing and mature rRNA formation in E. coli

Chukwudi, C U; Good, L


C U Chukwudi

L Good


In bacteria, RNase III cleaves the initial long primary ribosomal RNA transcripts/precursors (pre-rRNAs), thereby releasing the pre-16S and pre-23S rRNAs for maturation. This cleavage is specified by the double-stranded secondary structures flanking the mature rRNAs, and not necessarily by the nucleotide sequences. Inhibition of this cleavage would lead to a build-up of pre-rRNA molecules. Doxycycline has earlier been shown to bind synthetic double-stranded RNAs and inhibit their cleavage by RNase III. Since bacterial rRNA processing is primarily dependent on RNase III cleavage (which is inhibited by doxycycline), doxycycline could therefore inhibit the normal processing of bacterial rRNA. In this study, the effect of doxycycline on bacterial rRNA processing was investigated by analyzing the amounts of various rRNAs in growing Escherichia coli cells treated with doxycycline. The results showed a doxycycline dose-dependent decrease in mature 16S and 23S rRNAs, concurrent with an accumulation of the initial rRNA transcripts and long precursors. Morphologically, treated cells were elongated at low drug concentrations, while nucleoid degeneration indicative of cell death occurred at higher drug concentrations. These observations suggest that doxycycline inhibits the cleavage and processing of bacterial rRNA transcripts/precursors, leading to impaired formation of mature rRNAs, and the consequent inhibition of protein synthesis for which the tetracycline group of antibiotics are renowned. Since rRNA structure and processing pathway is conserved among bacterial species, this mechanism may account for the broad spectrum of antibiotic activity and selective microbial protein synthesis inhibition of doxycycline and the tetracyclines.


Chukwudi, C. U., & Good, L. (2019). Doxycycline inhibits pre-rRNA processing and mature rRNA formation in E. coli. Journal of Antibiotics, 72, 225-236.

Journal Article Type Article
Acceptance Date Jan 22, 2019
Publication Date Feb 8, 2019
Deposit Date Mar 1, 2019
Publicly Available Date Jul 9, 2019
Journal Journal of Antibiotics
Print ISSN 0021-8820
Publisher Springer Nature [academic journals on]
Peer Reviewed Peer Reviewed
Volume 72
Pages 225-236
Public URL