School of Ocean Science and Engineering, The University of Southern Mississippi, 112 McIlwain Drive, Ocean Springs, MS 39564, USA; Department of Biology, Francis Marion University, 4822 Palmetto Street, Florence, South Carolina, 29506, USA.
School of Ocean Science and Engineering, The University of Southern Mississippi, 112 McIlwain Drive, Ocean Springs, MS 39564, USA.
Aquat Toxicol. 2022 Oct;251:106267. doi: 10.1016/j.aquatox.2022.106267. Epub 2022 Aug 19.
DNA methylation is an important epigenetic mark involved in modulating transcription. While multiple studies document the ability of environmental stressors to alter methylation patterns, there is little information regarding the effects of oil and hypoxia on the methylome. Oil and hypoxic stress are threats in coastal ecosystems, which act as nursery habitats for developing fish. To explore the methylation altering effects of oil and hypoxia on developing fish, we exposed larval Cyprinodon variegatus to oil, hypoxia, or both for 48 h followed by 48 h of depuration in clean, normoxic conditions. We then used immunoprecipitation coupled with high-throughput sequencing (MeDIP seq) to evaluate genome-wide methylation changes. We also performed RNA seq to associate methylation and altered transcription. Oil and hypoxia together elicited greater impacts to methylation than either stressor individually. Additionally, the oil+hypoxia treatment exhibited an overlap between differentially methylated regions and differential gene expression at 20 loci. Functional analyses of these loci revealed enrichment of processes related to neurological function and development. Two neurological genes (slc1a2, asxl2) showed altered methylation of promoter CpG islands and transcriptional changes, suggesting epigenetic modulation of gene expression. Our results suggest a possible mechanism explaining altered behavior patterns noted in fish following oil exposure.
DNA 甲基化是一种重要的表观遗传标记，参与调节转录。虽然多项研究记录了环境胁迫因子改变甲基化模式的能力，但关于石油和缺氧对甲基组的影响的信息却很少。石油和缺氧应激是沿海生态系统的威胁，这些生态系统是鱼类发育的育苗栖息地。为了探索石油和缺氧对发育中的鱼类的甲基化改变效应，我们将幼鱼 Cyprinodon variegatus 暴露于石油、缺氧或两者中 48 小时，然后在清洁、常氧条件下进行 48 小时的净化。然后，我们使用免疫沉淀结合高通量测序（MeDIP seq）来评估全基因组的甲基化变化。我们还进行了 RNA seq，将甲基化与转录变化相关联。石油和缺氧的共同作用比任何单一胁迫因子对甲基化的影响都更大。此外，油+缺氧处理在 20 个基因座的差异甲基化区域和差异基因表达之间表现出重叠。这些基因座的功能分析显示，与神经功能和发育相关的过程富集。两个神经基因（slc1a2、asxl2）表现出启动子 CpG 岛的甲基化改变和转录变化，表明基因表达的表观遗传调控。我们的研究结果表明，一种可能的机制可以解释鱼类在暴露于石油后行为模式的改变。
