TY - JOUR T1 - Genotoxic and epigenetic effects of diuron in the Pacific oyster: in vitro evidence of interaction between DNA damage and DNA methylation A1 - Akcha,Farida A1 - Barranger,Audrey A1 - Bachère,Evelyne AD - Ifremer, Ecotoxicology Laboratory, Rue de l’Ile d’Yeu, BP21105, 44311, Nantes Cedex 03, France AD - Ifremer, UMR 5244, IHPE Interactions Hosts Pathogens Environment, UPVD, CNRS, University of Montpellier, CC 80, 34095, Montpellier, France UR - https://doi.org/10.1007/s11356-020-11021-6 DO - 10.1007/s11356-020-11021-6 KW - Genotoxicity KW - 8-oxodGuo KW - DNA adducts KW - DNA damage KW - DNA methylation KW - Oyster KW - Pesticide KW - Diuron N2 - Recently, research has contributed to better knowledge on the occurrence of pesticides in coastal water by identifying frequently detected substances, their concentration range and their acute and chronic toxicity for organisms. Pesticide pollution is of particular concern in France due to important agricultural activities and presence of several exoreic catchment areas that vehicle pesticides up to coastal waters, impacting non-target marine species. Several ecotoxicology questions remain to be addressed concerning the long-term effects of chronic pesticide exposure and the mechanisms involved in adaptation to chemical stress. In the present study, we brought new insights on the genetic and epigenetic effects of the herbicide diuron in oyster genitors. During gametogenesis, we exposed Crassostrea gigas to environmentally realistic herbicide concentrations (0.2–0.3 μg L−1 during two 7-day periods at half-course and end of gametogenesis). Diuron exposure was shown to decrease global DNA methylation and total methyltransferase activity in whole oyster tissue; this is consistent with the previous observation of a significant decrease in DNMT1 gene expression. Diuron effect seemed to be tissue-specific; hypermethylation was detected in the digestive gland, whereas diuron exposure had no effect on gill and gonad tissue. The genotoxicity of diuron was confirmed by the detection of one adduct in gonad DNA. By using in vitro approaches and human DNMT1 (DNMT1 has not been purified yet in bivalves), the presence of DNA lesions (adduct, 8-oxodGuo) was shown to interfere with DNMT1 activity, indicating a complex interaction between DNA damage and DNA methylation. Based on our results, we propose mechanisms to explain the effect of diuron exposure on DNA methylation, a widespread epigenetic mark. Y1 - 2021/02 PB - Springer Science and Business Media LLC JF - Environmental Science And Pollution Research SN - 0944-1344 VL - 28 IS - 7 SP - 8266 EP - 8280 ID - 76604 ER -