Disruption of the OLE ribonucleoprotein complex causes magnesium toxicity in Bacillus halodurans.
Kimberly A HarrisNicole B OdzerRonald R BreakerPublished in: Molecular microbiology (2019)
OLE RNAs represent an unusual class of bacterial noncoding RNAs common in Gram-positive anaerobes. The OLE RNA of the alkaliphile Bacillus halodurans is highly expressed and naturally interacts with at least two RNA-binding proteins called OapA and OapB. The phenotypes of the corresponding knockouts include growth inhibition when exposed to ethanol or other short-chain alcohols or when incubated at modestly reduced temperatures (e.g. 20°C). Intriguingly, the OapA 'PM1' mutant, which carries two amino acid changes to a highly conserved region, yields a dominant-negative phenotype that causes more severe growth defects under these same stress conditions. Herein, we report that the PM1 strain also exhibits extreme sensitivity to elevated Mg2+ concentrations, beginning as low as 2 mM. Suppressor mutants predominantly map to genes for aconitate hydratase and isocitrate dehydrogenase, which are expected to alter cellular citrate concentrations. Citrate reduces the severity of the Mg2+ toxicity phenotype, but neither the genomic mutations nor the addition of citrate to the medium overcomes ethanol toxicity or temperature sensitivity. These findings reveal that OLE RNA and its protein partners are involved in biochemical responses under several stress conditions, wherein the unusual sensitivity to Mg2+ can be independently suppressed by specific genomic mutations.
Keyphrases
- amino acid
- particulate matter
- oxidative stress
- air pollution
- genome wide
- wild type
- copy number
- nucleic acid
- heavy metals
- polycyclic aromatic hydrocarbons
- early onset
- transcription factor
- bacillus subtilis
- gram negative
- gene expression
- oxide nanoparticles
- single cell
- protein protein
- risk assessment
- human immunodeficiency virus
- african american
- drug induced
- hiv infected
- genome wide identification