Redpath Museum, McGill University, Montreal, Quebec, Canada.
Department of Biology, McGill University, Montreal, Quebec, Canada.
Mol Ecol. 2018 Aug;27(15):3087-3102. doi: 10.1111/mec.14771. Epub 2018 Jul 13.
Epigenetic modification, especially DNA methylation, can play an important role in mediating gene regulatory response to environmental stressors and may be a key process affecting phenotypic plasticity and adaptation. Parasites are potent stressors with profound physiological and ecological effects on their hosts, yet it remains unclear how parasites influence host methylation patterns. Here, we used a well-studied host-parasite system, the guppy Poecilia reticulata and its ectoparasitic monogenean Gyrodactylus turnbulli to gain mechanistic insight into the dynamics of DNA methylation in host-parasite interactions. To explore this, we quantitatively measured genome-wide DNA methylation in guppy skin tissue using reduced representation bisulphite sequencing and characterized differential methylation patterns in guppies during distinct phases of infection. We identified 365, 313, and 741 differentially methylated regions (DMRs) between infected and control fish in early infection, peak infection and recovery phases, respectively. The magnitude of the methylation difference was moderate in DMRs, with an average of 29% (early infection), 27% (peak infection) and 30% (recovery) differential methylation per DMR. Approximately 50% of DMRs overlapped with CpG islands, and over half of the DMRs overlapped with gene bodies, several of which encode proteins relevant to immune response. These findings provide the first evidence of an epigenetic signature of infection by ectoparasites and demonstrate the changing relationship between epigenetic variation and immune response in distinct phases of infection.
表观遗传修饰，特别是 DNA 甲基化，在介导基因对环境胁迫的调控反应中起着重要作用，可能是影响表型可塑性和适应的关键过程。寄生虫是强有力的胁迫因子，对宿主有深远的生理和生态影响，但目前尚不清楚寄生虫如何影响宿主的甲基化模式。在这里，我们使用了一个经过充分研究的宿主-寄生虫系统，即孔雀鱼 Poecilia reticulata 和它的外寄生单殖吸虫 Gyrodactylus turnbulli，以深入了解宿主-寄生虫相互作用中 DNA 甲基化的动态。为了探索这一点，我们使用简化代表性亚硫酸氢盐测序技术定量测量了孔雀鱼皮肤组织中的全基因组 DNA 甲基化，并在感染的不同阶段表征了孔雀鱼中的差异甲基化模式。我们在早期感染、感染高峰期和恢复期分别在感染和对照鱼之间鉴定了 365、313 和 741 个差异甲基化区域（DMR）。DMR 中的甲基化差异幅度适中，平均每个 DMR 的差异甲基化程度为 29%（早期感染）、27%（感染高峰期）和 30%（恢复期）。大约 50%的 DMR 与 CpG 岛重叠，超过一半的 DMR 与基因体重叠，其中一些基因编码与免疫反应相关的蛋白质。这些发现为外寄生虫感染的表观遗传特征提供了第一个证据，并证明了在感染的不同阶段，表观遗传变异与免疫反应之间的变化关系。
