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Methylation damage to RNA induced in vivo in Escherichia coli is repaired by endogenous AlkB as part of the adaptive response
- Source :
- DNA Repair. 12:188-195
- Publication Year :
- 2013
- Publisher :
- Elsevier BV, 2013.
-
Abstract
- Cytotoxic 1-methyladenine (1-meA) and 3-methylcytosine (3-meC) lesions induced in DNA and RNA in vitro and in pre-damaged DNA and RNA bacteriophages in vivo are repaired by the Escherichia coli (E. coli) protein AlkB and a human homolog, ALKBH3. However, it is not known whether endogenous RNA is repaired in vivo by repair proteins present at physiological concentrations. The concept of RNA repair as a biologically relevant process has therefore remained elusive. Here, we demonstrate AlkB-mediated repair of endogenous RNA in vivo by measuring differences in lesion-accumulation in two independent AlkB-proficient and deficient E. coli strains during exposure to methyl methanesulfonate (MMS). Repair was observed both in AlkB-overproducing strains and in the wild-type strains after AlkB induction. RNA repair appeared to be highest in RNA species below 200 nucleotides in size, mainly comprising tRNAs. Strikingly, at least 10-fold more lesions were repaired in RNA than in DNA. This may be a consequence of some 30-fold higher levels of aberrant methylation in RNA than in DNA after exposure to MMS. A high primary kinetic isotope effect (>10) was measured using a deuterated methylated RNA substrate, D3-1me(rA), demonstrating that it is the catalytic step, and not the search step that is rate-limiting. Our results demonstrate that RNA repair by AlkB takes place in endogenous RNA as part of an adaptive response in wild-type E. coli cells.
- Subjects :
- DNA, Bacterial
Alkylating Agents
DNA Repair
DNA repair
AlkB
Biology
medicine.disease_cause
Methylation
Biochemistry
Mixed Function Oxygenases
chemistry.chemical_compound
Escherichia coli
medicine
Molecular Biology
Post-transcriptional regulation
Escherichia coli Proteins
RNA
Cell Biology
RNA repair
Methyl Methanesulfonate
Adaptation, Physiological
Molecular biology
Kinetics
RNA, Bacterial
chemistry
Enzyme Induction
biology.protein
DNA
Subjects
Details
- ISSN :
- 15687864
- Volume :
- 12
- Database :
- OpenAIRE
- Journal :
- DNA Repair
- Accession number :
- edsair.doi.dedup.....e4617e1a7f1357e23f939dc4eaf917ba