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ATP insertion opposite 8-oxo-deoxyguanosine by Pol4 mediates error-free tolerance in Schizosaccharomyces pombe.

Sastre-Moreno G, Sánchez A, Esteban V, Blanco L - Nucleic Acids Res. (2014)

Bottom Line: In cell extracts, misincorporation of ATP opposite 8oxodG was shown to be SpPol4-specific, although RNase H2 efficiently recognized the 8oxodG:AMP mispair to remove AMP and trigger error-free incorporation of dCTP.Moreover, we demonstrate that purified SpPol4 uses 8oxo-dGTP and 8oxo-GTP as substrates for DNA polymerization, although with poor efficiency compared to the incorporation of undamaged nucleotides opposite either 8oxodG or undamaged templates.This suggests that SpPol4 is specialized in tolerating 8oxodG as a DNA template, without contributing significantly to the accumulation of this lesion in the DNA.

View Article: PubMed Central - PubMed

Affiliation: Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma, 28049 Madrid, Spain.

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Model for SpPol4 contribution to S. pombe GO system. (A) Reactive oxygen species (ROS) can oxidize guanines in the genome of S. pombe. The absence of a OGG1 homolog in fission yeast suggests that the premutagenic 8oxodG:dC base pair could be persist in the DNA, prompting the incorporation of dATP during DNA replication. S. pombe MutY homolog (SpMYH) can remove the wrong dAMP from the 8oxodG:dAMP base pair, and other polymerases (not SpPol4) can directly reconstitute a 8oxodG:dCMP base pair. SpPol4 can tolerate 8oxodG, mainly during NHEJ, using preferably the abundant ATP. That inserted ribonucleotide is then removed by a speciailzed RER mechanism (*the enzymatic reactions are shown in detail in (B)). (B) Insertion of ATP by SpPol4 would not be harmful as RNase H2 can recognize 8oxodG:AMP base pairs to initiate RER, thus triggering the error-free bypass of 8oxodG coupled to strand displacement, and preventing mutagenesis.
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Figure 9: Model for SpPol4 contribution to S. pombe GO system. (A) Reactive oxygen species (ROS) can oxidize guanines in the genome of S. pombe. The absence of a OGG1 homolog in fission yeast suggests that the premutagenic 8oxodG:dC base pair could be persist in the DNA, prompting the incorporation of dATP during DNA replication. S. pombe MutY homolog (SpMYH) can remove the wrong dAMP from the 8oxodG:dAMP base pair, and other polymerases (not SpPol4) can directly reconstitute a 8oxodG:dCMP base pair. SpPol4 can tolerate 8oxodG, mainly during NHEJ, using preferably the abundant ATP. That inserted ribonucleotide is then removed by a speciailzed RER mechanism (*the enzymatic reactions are shown in detail in (B)). (B) Insertion of ATP by SpPol4 would not be harmful as RNase H2 can recognize 8oxodG:AMP base pairs to initiate RER, thus triggering the error-free bypass of 8oxodG coupled to strand displacement, and preventing mutagenesis.

Mentions: One of the most common lesions generated by oxidative stress is 8oxodG. It arises in the DNA upon guanine oxidation (Figure 9A), and is promutagenic due to its ability to mispair with adenine. In mammalian cells, 8oxodG is mainly repaired by BER, in a process initiated by OGG1 (homolog of MutM in E. coli). The absence of an OGG1 homologue in S. pombe suggests that 8oxodG:dC base pairs could be left unrepaired, thus promoting misincorporation of dATP most likely during DNA replication with a potential impact in mutagenesis (Figure 9A). However, most of these errors should be eliminated by MutY, conserved in fission yeast (SpMYH), by excising the adenine from 8oxodG:dA base pairs (20) (Figure 9A). Coupled to the action of MutY homologs (MYH), a specialized polymerase able to copy 8oxodG in an error-free manner is considered indispensable to avoid mutagenesis, as replicative DNA polymerases display a reduced efficiency and fidelity when tolerating this lesion.


ATP insertion opposite 8-oxo-deoxyguanosine by Pol4 mediates error-free tolerance in Schizosaccharomyces pombe.

Sastre-Moreno G, Sánchez A, Esteban V, Blanco L - Nucleic Acids Res. (2014)

Model for SpPol4 contribution to S. pombe GO system. (A) Reactive oxygen species (ROS) can oxidize guanines in the genome of S. pombe. The absence of a OGG1 homolog in fission yeast suggests that the premutagenic 8oxodG:dC base pair could be persist in the DNA, prompting the incorporation of dATP during DNA replication. S. pombe MutY homolog (SpMYH) can remove the wrong dAMP from the 8oxodG:dAMP base pair, and other polymerases (not SpPol4) can directly reconstitute a 8oxodG:dCMP base pair. SpPol4 can tolerate 8oxodG, mainly during NHEJ, using preferably the abundant ATP. That inserted ribonucleotide is then removed by a speciailzed RER mechanism (*the enzymatic reactions are shown in detail in (B)). (B) Insertion of ATP by SpPol4 would not be harmful as RNase H2 can recognize 8oxodG:AMP base pairs to initiate RER, thus triggering the error-free bypass of 8oxodG coupled to strand displacement, and preventing mutagenesis.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150805&req=5

Figure 9: Model for SpPol4 contribution to S. pombe GO system. (A) Reactive oxygen species (ROS) can oxidize guanines in the genome of S. pombe. The absence of a OGG1 homolog in fission yeast suggests that the premutagenic 8oxodG:dC base pair could be persist in the DNA, prompting the incorporation of dATP during DNA replication. S. pombe MutY homolog (SpMYH) can remove the wrong dAMP from the 8oxodG:dAMP base pair, and other polymerases (not SpPol4) can directly reconstitute a 8oxodG:dCMP base pair. SpPol4 can tolerate 8oxodG, mainly during NHEJ, using preferably the abundant ATP. That inserted ribonucleotide is then removed by a speciailzed RER mechanism (*the enzymatic reactions are shown in detail in (B)). (B) Insertion of ATP by SpPol4 would not be harmful as RNase H2 can recognize 8oxodG:AMP base pairs to initiate RER, thus triggering the error-free bypass of 8oxodG coupled to strand displacement, and preventing mutagenesis.
Mentions: One of the most common lesions generated by oxidative stress is 8oxodG. It arises in the DNA upon guanine oxidation (Figure 9A), and is promutagenic due to its ability to mispair with adenine. In mammalian cells, 8oxodG is mainly repaired by BER, in a process initiated by OGG1 (homolog of MutM in E. coli). The absence of an OGG1 homologue in S. pombe suggests that 8oxodG:dC base pairs could be left unrepaired, thus promoting misincorporation of dATP most likely during DNA replication with a potential impact in mutagenesis (Figure 9A). However, most of these errors should be eliminated by MutY, conserved in fission yeast (SpMYH), by excising the adenine from 8oxodG:dA base pairs (20) (Figure 9A). Coupled to the action of MutY homologs (MYH), a specialized polymerase able to copy 8oxodG in an error-free manner is considered indispensable to avoid mutagenesis, as replicative DNA polymerases display a reduced efficiency and fidelity when tolerating this lesion.

Bottom Line: In cell extracts, misincorporation of ATP opposite 8oxodG was shown to be SpPol4-specific, although RNase H2 efficiently recognized the 8oxodG:AMP mispair to remove AMP and trigger error-free incorporation of dCTP.Moreover, we demonstrate that purified SpPol4 uses 8oxo-dGTP and 8oxo-GTP as substrates for DNA polymerization, although with poor efficiency compared to the incorporation of undamaged nucleotides opposite either 8oxodG or undamaged templates.This suggests that SpPol4 is specialized in tolerating 8oxodG as a DNA template, without contributing significantly to the accumulation of this lesion in the DNA.

View Article: PubMed Central - PubMed

Affiliation: Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma, 28049 Madrid, Spain.

Show MeSH
Related in: MedlinePlus