Abstract：
Circadian genes such as Clock, Bmal1, Cryptochrome1/2, and Period1/2/3 constitute the precise circadian system. ClockΔ19 is a commonly used mouse model harboring a circadian clock gene mutation, which lacks the EXON-19-encoded 51 amino acids. Previous reports have shown that ClockΔ19 mice have severe metabolic abnormalities. Here, we report that the mitochondria of ClockΔ19 mice exhibit excessive fission and dysfunction. We also demonstrate that CLOCK binds to the RNA-binding protein PUF60 through its EXON 19. Further, we find that PUF60 directly maintains mitochondrial homeostasis through regulating Drp1 mRNA stability, while the association with CLOCK can competitively inhibit this function. In ClockΔ19 mice, CLOCKΔ19 releases PUF60, leading to enhanced Drp1 mRNA stability and persistent mitochondrial fission. Our results reveal a direct post-transcriptional role of CLOCK in regulating mitochondrial homeostasis via Drp1 mRNA stability and that the loss of EXON 19 of CLOCK in ClockΔ19 mice leads to severe mitochondrial homeostasis disorders.
摘要：
昼夜节律基因，如时钟，Bmal1，Cryptochrome1/2和Period1/2/3构成了精确的昼夜节律系统。ClockΔ19是一种常用的具有昼夜节律基因突变的小鼠模型，缺少EXON-19编码的51个氨基酸。以前的报道显示ClockΔ19小鼠具有严重的代谢异常。这里,我们报道ClockΔ19小鼠的线粒体表现出过度的裂变和功能障碍。我们还证明CLOCK通过其外显子19与RNA结合蛋白PUF60结合。Further,我们发现PUF60通过调节Drp1mRNA的稳定性直接维持线粒体稳态，而与CLOCK的关联可以竞争性地抑制这一功能。在ClockΔ19小鼠中，CLOCKΔ19释放PUF60，导致Drp1mRNA稳定性增强和持续的线粒体裂变。我们的结果揭示了CLOCK在通过Drp1mRNA稳定性调节线粒体稳态中的直接转录后作用，并且ClockΔ19小鼠中CLOCK外显子19的丢失会导致严重的线粒体稳态紊乱。
