Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montréal, QC H1X 2B2, Canada.
Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.
Proc Natl Acad Sci U S A. 2022 Jul 26;119(30):e2122335119. doi: 10.1073/pnas.2122335119. Epub 2022 Jul 18.
Many cells specialize for different metabolic tasks at different times over their normal ZT cycle by changes in gene expression. However, in most cases, circadian gene expression has been assessed at the mRNA accumulation level, which may not faithfully reflect protein synthesis rates. Here, we use ribosome profiling in the dinoflagellate to identify thousands of transcripts showing coordinated translation. All of the components in carbon fixation are concurrently regulated at ZT0, predicting the known rhythm of carbon fixation, and many enzymes involved in DNA replication are concurrently regulated at ZT12, also predicting the known rhythm in this process. Most of the enzymes in glycolysis and the TCA cycle are also regulated together, suggesting rhythms in these processes as well. Surprisingly, a third cluster of transcripts show peak translation at approximately ZT16, and these transcripts encode enzymes involved in transcription, translation, and amino acid biosynthesis. The latter has physiological consequences, as measured free amino acid levels increase at night and thus represent a previously undocumented rhythm in this model. Our results suggest that ribosome profiling may be a more accurate predictor of changed metabolic state than transcriptomics.
许多细胞在其正常 ZT 周期内通过基因表达的变化专门从事不同的代谢任务。然而，在大多数情况下，生物钟基因表达都是在 mRNA 积累水平上进行评估的，而这可能无法真实反映蛋白质合成率。在这里，我们使用甲藻中的核糖体分析来鉴定数千个显示协调翻译的转录本。所有碳固定的成分都在 ZT0 同时被调控，预测了已知的碳固定节律，而许多参与 DNA 复制的酶在 ZT12 也同时被调控，也预测了这一过程的已知节律。糖酵解和 TCA 循环中的大多数酶也被一起调控，表明这些过程也存在节律。令人惊讶的是，第三组转录本在大约 ZT16 时显示出翻译峰，这些转录本编码参与转录、翻译和氨基酸生物合成的酶。后者具有生理后果，如夜间游离氨基酸水平增加，因此代表了该模型中以前未记录的节律。我们的结果表明，核糖体分析可能比转录组学更能准确预测代谢状态的变化。
