Background mutational features of the radiation-resistant bacterium deinococcus radiodurans

Hongan Long, Sibel Kucukyildirim, Way Sung, Emily Williams, Heewook Lee, Matthew Ackerman, Thomas G. Doak, Haixu Tang, Michael Lynch

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Deinococcus bacteria are extremely resistant to radiation, oxidation, and desiccation. Resilience to these factors has been suggested to be due to enhanced damage prevention and repair mechanisms, as well as highly efficient antioxidant protection systems. Here, using mutation-accumulation experiments, we find that the GC-rich Deinococcus radiodurans has an overall background genomicmutation rate similar to that of E. coli, but differs inmutation spectrum, with the A/T to G/C mutation rate (based on a total count of 88 A:T→G:C transitions and 82 A:T→C:G transversions) per site per generation higher than that in the other direction (based on a total count of 157 G:C→A:T transitions and 33 G:C→T:A transversions).We propose that this unique spectrumis shaped mainly by the abundant uracil DNA glycosylases reducing G:C→A:T transitions, adenine methylation elevating A:T→C:G transversions, and absence of cytosine methylation decreasing G:C→A:T transitions. As opposed to the greater than 100 elevation of the mutation rate in MMR (DNA Mismatch Repair deficient) strains of most other organisms,MMR D. radiodurans only exhibits a 4-fold elevation, raising the possibility that other DNA repair mechanisms compensate for a relatively low-efficiency DNA MMR pathway. As D. radiodurans has plentiful insertion sequence (IS) elements in the genome and the activities of IS elements are rarely directly explored, we also estimated the insertion (transposition) rate of the IS elements to be 2.50×103 per genome per generation in the wild-type strain; knocking out MMR did not elevate the IS element insertion rate in this organism.

Original languageEnglish (US)
Pages (from-to)2383-2392
Number of pages10
JournalMolecular biology and evolution
Volume32
Issue number9
DOIs
StatePublished - 2015

Keywords

  • DNA mismatch repair
  • Deinococcus radiodurans
  • Mutation accumulation
  • Mutation rate
  • Mutation spectrum

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics

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    Long, H., Kucukyildirim, S., Sung, W., Williams, E., Lee, H., Ackerman, M., Doak, T. G., Tang, H., & Lynch, M. (2015). Background mutational features of the radiation-resistant bacterium deinococcus radiodurans. Molecular biology and evolution, 32(9), 2383-2392. https://doi.org/10.1093/molbev/msv119