Alkylating Agents Induce Uvm, a Reca-Independent Inducible Mutagenic Phenomenon in Escherichia Coli
AUTOR(ES)
Wang, G.
RESUMO
Noninstructive DNA damage in Escherichia coli induces SOS functions hypothesized to be required for mutagenesis and translesion DNA synthesis at noncoding DNA lesions. We have recently demonstrated that in E. coli cells incapable of SOS induction, prior UV-irradiation nevertheless strongly enhances mutagenesis at a noninstructive lesion borne on M13 DNA. Here, we address the question whether this effect, named UVM for UV modulation of mutagenesis, can be induced by other DNA damaging agents. Exponentially growing δrecA cells were pretreated with alkylating agents before transfection with M13 single-stranded DNA bearing a site-specific ethenocytosine residue. Effect of cell pretreatment on survival of the transfected DNA was determined as transfection efficiency. Mutagenesis at the ethenocytosine site in pretreated or untreated cells was analyzed by multiplex DNA sequencing, a phenotype-independent technology. Our data show that 1-methyl-3-nitro-1-nitrosoguanidine, N-nitroso-N-methylurea and dimethylsulfate, but not methyl iodide, are potent inducers of UVM. Because alkylating agents induce the adaptive response to defend against DNA alkylation, we asked if the genes constituting the adaptive response are required for UVM. Our data show that MNNG induction of UVM is independent of ada, alkA and alkB genes and define UVM as an inducible mutagenic phenomenon distinct from the E. coli adaptive and SOS responses.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1206846Documentos Relacionados
- A Sister-Strand Exchange Mechanism for Reca-Independent Deletion of Repeated DNA Sequences in Escherichia Coli
- RecA-Independent Pathways of Lambdoid Prophage Induction in Escherichia coli
- The Mechanism of Reca Pola Lethality: Suppression by Reca-Independent Recombination Repair Activated by the Lexa(def) Mutation in Escherichia Coli
- Transcription promotes recA-independent recombination mediated by DNA-dependent RNA polymerase in Escherichia coli.
- Method for gene replacement in Pseudomonas aeruginosa used in construction of recA mutants: recA-independent instability of alginate production.