TY - JOUR
T1 - Background mutational features of the radiation-resistant bacterium deinococcus radiodurans
AU - Long, Hongan
AU - Kucukyildirim, Sibel
AU - Sung, Way
AU - Williams, Emily
AU - Lee, Heewook
AU - Ackerman, Matthew
AU - Doak, Thomas G.
AU - Tang, Haixu
AU - Lynch, Michael
N1 - Publisher Copyright:
© 2015 The Author.
PY - 2015/9
Y1 - 2015/9
N2 - 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.
AB - 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.
KW - DNA mismatch repair
KW - Deinococcus radiodurans
KW - Mutation accumulation
KW - Mutation rate
KW - Mutation spectrum
UR - http://www.scopus.com/inward/record.url?scp=84943608703&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84943608703&partnerID=8YFLogxK
U2 - 10.1093/molbev/msv119
DO - 10.1093/molbev/msv119
M3 - Article
C2 - 25976352
AN - SCOPUS:84943608703
SN - 0737-4038
VL - 32
SP - 2383
EP - 2392
JO - Molecular biology and evolution
JF - Molecular biology and evolution
IS - 9
ER -