Instituto de Acuicultura Torre de la Sal, CSIC, 12595 Torre de la Sal, Castellón, Spain.
UMR-I 02 Environmental Stress and Aquatic Biomonitoring (SEBIO), University of Le Havre Normandy, F-76600 Le Havre, France.
J Steroid Biochem Mol Biol. 2024 Feb;236:106423. doi: 10.1016/j.jsbmb.2023.106423. Epub 2023 Nov 7.
Across vertebrates, the numerous estrogenic functions are mainly mediated by nuclear and membrane receptors, including the G protein-coupled estrogen receptor (GPER) that has been mostly associated with rapid non-genomic responses. Although Gper-mediated signalling has been characterized in only few fish species, Gpers in fish appear to present more mechanistic functionalities as those of mammals due to additional gene duplicates. In this study, we ran a thorough investigation of the fish Gper evolutionary history in light of available genomes, we carried out the functional characterization of the two gper gene duplicates of European sea bass (Dicentrarchus labrax) using luciferase reporter gene transactivation assays, validated it with natural and synthetic estrogen agonists/antagonists and applied it to other chemicals of aquaculture and ecotoxicological interest. Phylogenetic and synteny analyses of fish gper1 and gper1-like genes suggest their duplication may have not resulted from the teleost-specific whole genome duplication. We confirmed that both sbsGper isoforms activate the cAMP signalling pathway and respond differentially to distinct estrogenic compounds. Therefore, as observed for nuclear estrogen receptors, both sbsGpers duplicates retain estrogenic activity although they differ in their specificity and potency (Gper1 being more potent and more specific than Gper1-like), suggesting a more conserved role for Gper1 than for Gper1-like. In addition, Gpers were able to respond to estrogenic environmental pollutants known to interfere with estrogen signalling, such as the phytoestrogen genistein and the anti-depressant fluoxetine, a point that can be taken into account in aquatic environment pollution screenings and chemical risk assessment, complementing previous assays for sea bass nuclear estrogen receptors.
在脊椎动物中，许多雌激素功能主要是通过核受体和膜受体介导的，包括 G 蛋白偶联雌激素受体（GPER），它主要与快速非基因组反应有关。尽管 Gper 介导的信号转导在少数鱼类物种中得到了描述，但由于额外的基因重复，鱼类中的 Gpers 似乎具有比哺乳动物更多的机制功能。在这项研究中，我们根据现有基因组对鱼类 Gper 的进化历史进行了全面研究，我们使用荧光素酶报告基因转染实验对欧洲鲈鱼（Dicentrarchus labrax）的两个 gper 基因重复进行了功能表征，并用天然和合成雌激素激动剂/拮抗剂进行了验证，并将其应用于其他水产养殖和生态毒理学感兴趣的化学物质。鱼类 gper1 和 gper1 样基因的系统发育和基因排列分析表明，它们的重复可能不是由于硬骨鱼特有的全基因组重复导致的。我们证实，这两种 sbsGper 同工型都能激活 cAMP 信号通路，并对不同的雌激素化合物产生不同的反应。因此，正如核雌激素受体所观察到的，尽管它们在特异性和效力上存在差异（gper1 比 gper1 样更有效力和特异性），但这两种 sbsGper 重复都保留了雌激素活性，这表明 gper1 比 gper1 样具有更保守的作用。此外，Gper 能够对已知会干扰雌激素信号的雌激素环境污染物（如植物雌激素金雀异黄素和抗抑郁药氟西汀）作出反应，这一点可以在水生环境污染物筛查和化学风险评估中得到考虑，补充了以前对鲈鱼核雌激素受体的研究。
