Open AccessDefects in the Error Prevention Oxidized Guanine System Potentiate Stationary-Phase Mutagenesis in Bacillus subtilis
Author(s) -
Luz E. Vidales,
Lluvia C. Cárdenas,
Eduardo A. Robleto,
Ronald E. Yasbin,
Mario Pedraza-Reyes
Publication year - 2009
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.01210-08
Subject(s) - bacillus subtilis , biology , operon , mutagenesis , mutant , mutation , stationary phase , genetics , dna repair , oxidative stress , dna , gene , microbiology and biotechnology , bacteria , biochemistry , chemistry , chromatography
Previous studies showed that aBacillus subtilis strain deficient in mismatch repair (MMR; encoded by themutSL operon) promoted the production of stationary-phase-induced mutations. However, overexpression of themutSL operon did not completely suppress this process, suggesting that additional DNA repair mechanisms are involved in the generation of stationary-phase-associated mutants in this bacterium. In agreement with this hypothesis, the results presented in this work revealed that starvedB. subtilis cells lacking a functional error prevention GO (8-oxo-G) system (composed of YtkD, MutM, and YfhQ) had a dramatic propensity to increase the number of stationary-phase-induced revertants. These results strongly suggest that the occurrence of mutations is exacerbated by reactive oxygen species in nondividing cells ofB. subtilis having an inactive GO system. Interestingly, overexpression of the MMR system significantly diminished the accumulation of mutations in cells deficient in the GO repair system during stationary phase. These results suggest that the MMR system plays a general role in correcting base mispairing induced by oxidative stress during stationary phase. Thus, the absence or depression of both the MMR and GO systems contributes to the production of stationary-phase mutants inB. subtilis. In conclusion, our results support the idea that oxidative stress is a mechanism that generates genetic diversity in starved cells ofB. subtilis , promoting stationary-phase-induced mutagenesis in this soil microorganism.