To the extent possible under law, AOP-Wiki has waived all copyright and related or neighboring rights to KER:1914

Relationship: 1914


A descriptive phrase which clearly defines the two KEs being considered and the sequential relationship between them (i.e., which is upstream, and which is downstream). More help

Increase, Oxidative DNA damage leads to Increase, Mutations

Upstream event
The causing Key Event (KE) in a Key Event Relationship (KER). More help
Downstream event
The responding Key Event (KE) in a Key Event Relationship (KER). More help

Key Event Relationship Overview

The utility of AOPs for regulatory application is defined, to a large extent, by the confidence and precision with which they facilitate extrapolation of data measured at low levels of biological organisation to predicted outcomes at higher levels of organisation and the extent to which they can link biological effect measurements to their specific causes. Within the AOP framework, the predictive relationships that facilitate extrapolation are represented by the KERs. Consequently, the overall WoE for an AOP is a reflection in part, of the level of confidence in the underlying series of KERs it encompasses. Therefore, describing the KERs in an AOP involves assembling and organising the types of information and evidence that defines the scientific basis for inferring the probable change in, or state of, a downstream KE from the known or measured state of an upstream KE. More help

AOPs Referencing Relationship

AOP Name Adjacency Weight of Evidence Quantitative Understanding Point of Contact Author Status OECD Status
Oxidative DNA damage leading to chromosomal aberrations and mutations non-adjacent High Low Carole Yauk (send email) Open for comment. Do not cite EAGMST Approved

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KER.In general, this will be dictated by the more restrictive of the two KEs being linked together by the KER.  More help
Term Scientific Term Evidence Link
human Homo sapiens NCBI
rat Rattus norvegicus NCBI
mice Mus sp. NCBI

Sex Applicability

An indication of the the relevant sex for this KER. More help
Sex Evidence

Life Stage Applicability

An indication of the the relevant life stage(s) for this KER.  More help
Term Evidence
All life stages

Key Event Relationship Description

Provides a concise overview of the information given below as well as addressing details that aren’t inherent in the description of the KEs themselves. More help

Oxidative DNA lesions such as 7, 8-dihydro-8oxo-deoxyGuanine (8-oxo-dG) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FaPydG) are mutagenic because if they are not repaired they are able to form base pairs with dATP instead dCTP during replication. This can lead to permanent changes in the DNA sequence that is inherited by daughter cells with subsequent replication. G:C→T:A transversions are the most abundant base substitution attributed to oxidative DNA lesions (Cadet and Wagner, 2013).

Evidence Collection Strategy

Include a description of the approach for identification and assembly of the evidence base for the KER.  For evidence identification, include, for example, a description of the sources and dates of information consulted including expert knowledge, databases searched and associated search terms/strings.  Include also a description of study screening criteria and methodology, study quality assessment considerations, the data extraction strategy and links to any repositories/databases of relevant references.Tabular summaries and links to relevant supporting documentation are encouraged, wherever possible. More help

Evidence Supporting this KER

Addresses the scientific evidence supporting KERs in an AOP setting the stage for overall assessment of the AOP. More help
Biological Plausibility
Addresses the biological rationale for a connection between KEupstream and KEdownstream.  This field can also incorporate additional mechanistic details that help inform the relationship between KEs, this is useful when it is not practical/pragmatic to represent these details as separate KEs due to the difficulty or relative infrequency with which it is likely to be measured.   More help

Mutagenicity of oxidative DNA lesions has been extensively studied; incorrect base insertion opposite unrepaired oxidative DNA lesions during replication is a well-established event.

For example, 8-oxo-dG and FaPydG, the two most prominent oxidative DNA lesions, are able to form base pairs with dATP, giving rise to G:C→T:A transversions with subsequent DNA synthesis (Gehrke et al., 2013; Freudenthal et al., 2013; Markkanen, 2017). Replicative DNA polymerases such as DNA polymerase α, δ, and ε (pol α, δ, ε) have a poor ability to extend the DNA strand past 8-oxo-dG:dCTP base pairs and may cause replication to stall or incorrectly insert dATP opposite 8-oxo-dG (Hashimoto et al., 2004; Markkanen et al., 2012). In stalled replication forks, repair polymerases may be recruited to perform translesion DNA synthesis (TLS). Human Y-family DNA polymerases (Rev 1, pol κ, ι, and η) are DNA repair polymerases mainly involved in TLS for stalled replication forks. However, TLS is not free of error and its accuracy differs for each repair polymerase. For example, it is known that pol κ and η perform TLS across 8-oxo-dG and often insert dATP opposite the lesion, generating G:C→T:A transversions. The error-prone nature of bypassing unrepaired oxidative lesions has been described in many previous studies and reviews (Greenberg, 2012; Maddukuri et al., 2014; Taggart et al., 2014; Sha et al., 2017).

Uncertainties and Inconsistencies
Addresses inconsistencies or uncertainties in the relationship including the identification of experimental details that may explain apparent deviations from the expected patterns of concordance. More help

The provided empirical evidence examined only the quantities of 8-oxo-dG and related the observed mutations to this oxidative lesion; the level of overall DNA oxidation is inferred from the level of 8-oxo-dG present. It is unclear how other oxidative DNA lesions such as FapyG, FapyA, and thymidine glycol contribute to the mutation spectra and frequencies.

Known modulating factors

This table captures specific information on the MF, its properties, how it affects the KER and respective references.1.) What is the modulating factor? Name the factor for which solid evidence exists that it influences this KER. Examples: age, sex, genotype, diet 2.) Details of this modulating factor. Specify which features of this MF are relevant for this KER. Examples: a specific age range or a specific biological age (defined by...); a specific gene mutation or variant, a specific nutrient (deficit or surplus); a sex-specific homone; a certain threshold value (e.g. serum levels of a chemical above...) 3.) Description of how this modulating factor affects this KER. Describe the provable modification of the KER (also quantitatively, if known). Examples: increase or decrease of the magnitude of effect (by a factor of...); change of the time-course of the effect (onset delay by...); alteration of the probability of the effect; increase or decrease of the sensitivity of the downstream effect (by a factor of...) 4.) Provision of supporting scientific evidence for an effect of this MF on this KER. Give a list of references.  More help
Response-response Relationship
Provides sources of data that define the response-response relationships between the KEs.  More help
Information regarding the approximate time-scale of the changes in KEdownstream relative to changes in KEupstream (i.e., do effects on KEdownstream lag those on KEupstream by seconds, minutes, hours, or days?). More help
Known Feedforward/Feedback loops influencing this KER
Define whether there are known positive or negative feedback mechanisms involved and what is understood about their time-course and homeostatic limits. More help

Domain of Applicability

A free-text section of the KER description that the developers can use to explain their rationale for the taxonomic, life stage, or sex applicability structured terms. More help

DNA in any cell type is susceptible to oxidative damage due to endogenous (e.g., aerobic respiration) and exogenous (i.e., exposure to oxidants) oxidative insults. Resulting increase in mutation frequency has been described in both eukaryotic and prokaryotic cells.


List of the literature that was cited for this KER description. More help

Cadet, J., Wagner, J.R. (2013), DNA Base Damage by Reactive Oxygen Species, Oxidizing Agents, and UV Radiation, Cold Spring Harb Perspect Biol, 5:a012559.

Freudenthal, B., Beard, W., Wilson, S. (2013), DNA polymerase minor groove interactions modulate mutagenic bypass of a templating 8-oxoguanine lesion., Nucleic Acids Res, 41:1848-1858.

Gehrke, T., Lischke, U., Gasteiger, K., Schneider, S., Arnold, S., Muller, H., Stephenson, D., Zipse, H., Carell, T. (2013), Unexpected non-Hoogsteen–based mutagenicity mechanism of FaPy-DNA lesions, Nat Chem Biol, 9:455-461.

Greenberg, M. (2012), Purine Lesions Formed in Competition With 8-Oxopurines From Oxidative Stress, Acc Chem Res, 45:588-597.

Hashimoto, K., Tominaga, Y., Nakabeppu, Y., Moriya, M. (2004), Futile short-patch DNA base excision repair of adenine:8-oxoguanine mispair, Nucleic Acids Res, 32:5928-5934.

Klungland, A., Rosewell, I., Hollenbach, S., Larsen, E., Daly, G., Epe, B., Seeberg, E., Lindahl, T., Barnes, D. (1999), Accumulation of premutagenic DNA lesions in mice defective in removal of oxidative base damage, Proc Natl Acad Sci USA, 96:13300-13305.

Maddukuri, L., Ketkar, A., Eddy, S., Zafar, M., Eoff, R. (2014), The Werner syndrome protein limits the error-prone 8-oxo-dG lesion bypass activity of human DNA polymerase kappa, Nucleic Acids Res, 42:12027-12040.

Markkanen, E. (2017), Not breathing is not an option: How to deal with oxidative DNA damage, DNA Repair, 59:82-105.

Markkanen, E., Castrec, B., Vilani, G., Hubscher, U. (2012), A switch between DNA polymerases δ and λ promotes error-free bypass of 8-oxo-G lesions, Proc Natl Acad Sci USA, 27:931-940.

Platel, A., Nesslany, F., Gervais, V., Claude, N., Marzin, D. (2011), Study of oxidative DNA damage in TK6 human lymphoblastoid cells by use of the thymidine kinase gene-mutation assay and the in vitro modified comet assay: Determination of No-Observed-Genotoxic-Effect-Levels, Mutat Res, 726:151-159.

Sha, Y., Minko, I., Malik, C., Rizzo, C., Lloyd, R.S. (2017), Error-Prone Replication Bypass of the Imidazole Ring-Opened Formamidopyrimidine Deoxyguanosine Adduct, Envrion Mol Mutatgen, 58:182-189.

Taggart, D., Fredrickson, S., Gadkari, V., Suo, Z. (2014), Mutagenic Potential of 8-Oxo-7,8-dihydro-2′-deoxyguanosine Bypass Catalyzed by Human Y-Family DNA Polymerases, Chem Res Toxicol, 27:931-940.

Takumi, S., Aoki, Y., Sano, T., Suzuki, T., Nohmi, T., Nohara, K. (2014), In vivo mutagenicity of arsenite in the livers of gpt delta transgenic mice  , Mutat Res, 760:42-47.

Unfried, K., Schurkes, C., Abel, J. (2002), Distinct Spectrum of Mutations Induced by Crocidolite Asbestos: Clue for 8-Hydroxydeoxyguanosine-dependent Mutagenesis in Vivo, Cancer Res, 62:104.