In response to seasonal droughts, the green striped burrowing frog enters a reversible hypometabolic state called aestivation where heart rate and oxygen consumption can be reduced despite warm (>25C°) ambient temperatures. With a view to understanding molecular mechanisms we profiled aestivating versus control gastrocnemius muscle using mRNA sequencing. This indicated an extensive metabolic reprogramming, with nearly a quarter of the entire transcriptome (3996 of 16,960 mRNA) exhibiting a nominal >2-fold change. Consistent with a physiological adaptation to spare carbohydrate reserves, carbohydrate catabolism was systemically downregulated. A 630-fold downregulation of encoding the enolase enzyme was most striking. The 590 frog orthologs of mRNA encoding the mitoproteome were, viewed as a population, significantly downregulated during aestivation, although not to the same extent as mRNA encoding carbohydrate catabolism. Prominent examples include members of the TCA cycle (), electron transport chain (), the ATP synthase complex () and ADP/ATP intracellular transport (). Moreover, mRNA derived from the mt genome itself (e.g. ) were also downregulated. Most prominent among the upregulated mRNA are those encoding aspects of regulated proteolysis including the proteosome (e.g. ), peptidases (), atrogins () and ubiquitination (). Finally, we note the ∼5-fold upregulation of the mRNA that encodes part of the EIF4F complex. This possesses global control of protein synthesis. Given protein synthesis is repressed in aestivating frogs this indicates the skeletal musculature is poised for accelerated translation of mRNA upon emergence, supporting a strategy to rapidly restore function when the summer rains come.

中文翻译：

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代谢低下肌肉中 mRNA 发生显着的全基因组重编程

为了应对季节性干旱，绿条纹穴居蛙会进入一种可逆的代谢低下状态，称为夏眠，尽管环境温度温暖（>25C°），但心率和耗氧量仍会降低。为了了解分子机制，我们使用 mRNA 测序对夏眠肌与对照腓肠肌进行了比较。这表明存在广泛的代谢重编程，整个转录组的近四分之一（16,960 个 mRNA 中的 3996 个）表现出名义上 >2 倍的变化。与节省碳水化合物储备的生理适应一致，碳水化合物分解代谢被系统性下调。最引人注目的是编码烯醇酶的 630 倍下调。编码线粒体蛋白质组的 590 个青蛙直系同源物被视为一个群体，在夏眠期间显着下调，尽管程度与编码碳水化合物分解代谢的 mRNA 不同。突出的例子包括 TCA 循环 ()、电子传递链 ()、ATP 合成酶复合物 () 和 ADP/ATP 细胞内转运 () 的成员。此外，源自mt基因组本身的mRNA（例如）也被下调。上调的 mRNA 中最突出的是那些编码受调节蛋白水解作用的 mRNA，包括蛋白体（例如）、肽酶（）、atrogins（）和泛素化（）。最后，我们注意到编码 EIF4F 复合物部分的 mRNA 上调了约 5 倍。它拥有对蛋白质合成的全局控制。鉴于冬眠青蛙的蛋白质合成受到抑制，这表明骨骼肌肉组织在出现后准备加速 mRNA 的翻译，支持在夏季降雨到来时快速恢复功能的策略。