Nofima AS, Osloveien 1, NO-1433, Ås, Norway.
Nofima AS, Muninbakken 9-13, NO-9291, Tromsø, Norway.
Sci Rep. 2017 Jul 10;7(1):5023. doi: 10.1038/s41598-017-05222-2.
Exposure to environmental stressors during early-life stages can change the rate and timing of various developmental processes. Epigenetic marks affecting transcriptional regulation can be altered by such environmental stimuli. To assess how stress might affect the methylome and transcriptome in salmon, fish were treated using cold-shock and air-exposure from the eye-stage until start-feeding. The fish were either stressed prior to hatching (E), post-hatching (PH), pre- and post-hatching (EPH) or not stressed (CO). Assessing transcriptional abundances just prior to start feeding, E and PH individuals were found to have modified the expression of thousands of genes, many with important functions in developmental processes. The EPH individuals however, showed expression similar to those of CO, suggesting an adaptive response to extended periods of stress. The methylome of stressed individuals differed from that of the CO, suggesting the importance of environment in shaping methylation signatures. Through integration of methylation with transcription, we identified bases with potential regulatory functions, some 10s of kb away from the targeted genes. We then followed fish growth for an additional year. Individuals in EPH showed superior growth compared to other treatment groups, highlighting how stress can potentially have long-lasting effects on an organism's ability to adapt to environmental perturbations.
早期生活阶段暴露于环境应激源会改变各种发育过程的速度和时间。影响转录调控的表观遗传标记可以被这种环境刺激改变。为了评估应激如何影响鲑鱼的甲基组和转录组，我们从眼球期开始用冷休克和空气暴露处理鱼，直到开始摄食。鱼要么在孵化前（E）、孵化后（PH）、孵化前和孵化后（EPH）受到应激，要么不受应激（CO）。在开始摄食前评估转录丰度时，发现 E 和 PH 个体改变了数千个基因的表达，其中许多基因在发育过程中具有重要功能。然而，EPH 个体的表达与 CO 相似，这表明它们对延长的应激期有适应反应。应激个体的甲基组与 CO 的不同，这表明环境在塑造甲基化特征方面的重要性。通过将甲基化与转录相结合，我们鉴定了一些潜在具有调控功能的碱基，它们距离靶基因有数十 kb 远。然后我们又对鱼进行了一年的生长跟踪。EPH 组的个体生长情况优于其他处理组，这突出表明应激可能对生物体适应环境扰动的能力产生持久影响。
