Department of Biology, Portland State University, Portland, Oregon
Department of Biology, Portland State University, Portland, Oregon.
Physiol Genomics. 2017 Sep 1;49(9):505-518. doi: 10.1152/physiolgenomics.00016.2017. Epub 2017 Aug 11.
Small noncoding RNAs (sncRNA) have recently emerged as specific and rapid regulators of gene expression, involved in a myriad of cellular and organismal processes. MicroRNAs, a class of sncRNAs, are differentially expressed in diverse taxa in response to environmental stress, including anoxia. In most vertebrates, a brief period of oxygen deprivation results in severe tissue damage or death. Studies on sncRNA and anoxia have focused on these anoxia-sensitive species. Studying sncRNAs in anoxia-tolerant organisms may provide insight into adaptive mechanisms supporting anoxia tolerance. Embryos of the annual killifish are the most anoxia-tolerant vertebrates known, surviving over 100 days at their peak tolerance at 25°C. Their anoxia tolerance and physiology vary over development, such that both anoxia-tolerant and anoxia-sensitive phenotypes comprise the species. This allows for a robust comparison to identify sncRNAs essential to anoxia-tolerance. For this study, RNA sequencing was used to identify and quantify expression of sncRNAs in four embryonic stages of in response to an exposure to anoxia and subsequent aerobic recovery. Unique stage-specific patterns of expression were identified that correlate with anoxia tolerance. In addition, embryos of appear to constitutively express stress-responsive miRNAs. Most differentially expressed sncRNAs were expressed at higher levels during recovery. Many novel groups of sncRNAs with expression profiles suggesting a key role in anoxia tolerance were identified, including sncRNAs derived from mitochondrial tRNAs. This global analysis has revealed groups of candidate sncRNAs that we hypothesize support anoxia tolerance.
小非编码 RNA（sncRNA）最近作为基因表达的特定和快速调节因子出现，参与了无数的细胞和生物体过程。miRNA 是一类 sncRNA，在不同的分类群中对环境压力（包括缺氧）表现出差异表达。在大多数脊椎动物中，短暂的缺氧会导致严重的组织损伤或死亡。关于 sncRNA 和缺氧的研究主要集中在这些对缺氧敏感的物种上。研究耐缺氧生物中的 sncRNA 可能有助于深入了解支持耐缺氧的适应机制。一年生的食蚊鱼的胚胎是已知的最耐缺氧的脊椎动物，在 25°C 时其最高耐受能力下可以存活超过 100 天。它们的耐缺氧能力和生理机能随发育而变化，因此该物种既有耐缺氧表型也有缺氧敏感表型。这使得可以进行强有力的比较，以确定对耐缺氧至关重要的 sncRNA。在这项研究中，使用 RNA 测序来鉴定和量化在食蚊鱼的四个胚胎阶段中对缺氧和随后的有氧恢复的 sncRNA 表达。鉴定出与耐缺氧相关的独特的阶段特异性表达模式。此外，食蚊鱼的胚胎似乎持续表达应激反应性 miRNA。在恢复期间，大多数差异表达的 sncRNA 的表达水平更高。许多具有表达谱表明在耐缺氧中起关键作用的新型 sncRNA 簇被鉴定出来，包括来自线粒体 tRNA 的 sncRNA。这种全面分析揭示了我们假设支持耐缺氧的候选 sncRNA 簇。
