Current evidence for a role of epigenetic mechanisms in response to ionizing radiation in an ecotoxicological context
Résumé
The issue of potential long-term or hereditary effects for both humans and wildlife exposed to low doses (or dose
rates) of ionising radiation is a major concern. Chronic exposure to ionising radiation, defined as an exposure over a
large fraction of the organism’s lifespan or even over several generations, can possibly have consequences in the
progeny. Recent work has begun to show that epigenetics plays an important role in adaptation of organisms
challenged to environmental stimulae. Changes to so-called epigenetic marks such as histone modifications, DNA
methylation and non-coding RNAs result in altered transcriptomes and proteomes, without directly changing the DNA
sequence. Moreover, some of these environmentally-induced epigenetic changes tend to persist over generations, and
thus, epigenetic modifications are regarded as the conduits for environmental influence on the genome. Here, we
review the current knowledge of possible involvement of epigenetics in the cascade of responses resulting from
environmental exposure to ionising radiation. In addition, from a comparison of lab and field obtained data, we
investigate evidence on radiation-induced changes in the epigenome and in particular the total or locus specific levels
of DNA methylation. The challenges for future research and possible use of changes as an early warning (biomarker)
of radiosensitivity and individual exposure is discussed. Such a biomarker could be used to detect and better
understand the mechanisms of toxic action and inter/intra-species susceptibility to radiation within an environmental
risk assessment and management context.
Domaines
Sciences de l'environnement
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