Hughes Chelsea, Mojica Elizabeth A, Kültz Dietmar, Podrabsky Jason E
Department of Biology, Center for Life in Extreme Environments, Portland State University, Portland, OR 97201, United States.
Department of Animal Sciences and Genome Center, University of California, Davis, Davis, CA 95616, United States.
Environ Epigenet. 2025 May 23;11(1):dvaf015. doi: 10.1093/eep/dvaf015. eCollection 2025.
Many organisms have adapted to survive anoxic or hypoxic environments, but the epigenetic responses involved in this successful stress response are not well described in most species. Embryos of the annual killifish have the greatest tolerance to anoxia of all vertebrates, making them a powerful model to study the cellular mechanisms necessary for anoxia tolerance. However, the global histone landscape of this species has never been quantified or explored in relation to stress tolerance. Liquid chromatography-mass spectrometry and a Python bioinformatics workflow were used to identify histones and their post-translational modifications. This pipeline resulted in the detection of 252 unique biologically relevant histone post-translational modifications (hPTMs) (unimod + residue). These PTMs represent 16 types of biologically relevant hPTMs present during both anoxia and normoxia in Wourms' stage 36 embryos. This hPTM library presents an exciting opportunity to study histone modifications across development and in response to environmental stressors. No significant changes in PTM or histone abundance were observed between anoxic and normoxic embryos, suggesting that 24 h of anoxia is not sufficient to induce epigenetic or histone isoform changes at the organismal level. This result is inconsistent with data presented for similar stresses in mammalian cells and thus stabilization of the hPTM landscape may be an adaptation that supports anoxia tolerance.
许多生物已经适应在缺氧或低氧环境中生存，但大多数物种中参与这种成功应激反应的表观遗传反应尚未得到充分描述。一年生鳉鱼的胚胎对缺氧的耐受性在所有脊椎动物中是最强的，这使其成为研究缺氧耐受性所需细胞机制的有力模型。然而，该物种的整体组蛋白情况从未针对应激耐受性进行过量化或探索。利用液相色谱 - 质谱联用技术和一个Python生物信息学工作流程来鉴定组蛋白及其翻译后修饰。该流程检测到252种独特的具有生物学相关性的组蛋白翻译后修饰（hPTM）（单峰 + 残基）。这些PTM代表了Wourms 36期胚胎在缺氧和常氧状态下均存在的16种具有生物学相关性的hPTM类型。这个hPTM文库为研究发育过程中以及对环境应激源反应时的组蛋白修饰提供了一个令人兴奋的机会。在缺氧和常氧胚胎之间未观察到PTM或组蛋白丰度的显著变化，这表明24小时的缺氧不足以在机体水平上诱导表观遗传或组蛋白异构体的变化。这一结果与哺乳动物细胞中类似应激的数据不一致，因此hPTM情况的稳定可能是一种支持缺氧耐受性的适应性变化。
