The circadian clock is encoded by a negative transcriptional feedback loop that coordinates physiology and behavior through molecular programs that remain incompletely understood. Here, we reveal rhythmic genome-wide alternative splicing (AS) of pre-mRNAs encoding regulators of peptidergic secretion within pancreatic β cells that are perturbed in Clock^−/− and Bmal1^−/− β-cell lines. We show that the RNA-binding protein THRAP3 (thyroid hormone receptor-associated protein 3) regulates circadian clock-dependent AS by binding to exons at coding sequences flanking exons that are more frequently skipped in clock mutant β cells, including transcripts encoding Cask (calcium/calmodulin-dependent serine protein kinase) and Madd (MAP kinase-activating death domain). Depletion of THRAP3 restores expression of the long isoforms of Cask and Madd, and mimicking exon skipping in these transcripts through antisense oligonucleotide delivery in wild-type islets reduces glucose-stimulated insulin secretion. Finally, we identify shared networks of alternatively spliced exocytic genes from islets of rodent models of diet-induced obesity that significantly overlap with clock mutants. Our results establish a role for pre-mRNA alternative splicing in β-cell function across the sleep/wake cycle.

中文翻译：

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选择性剪接在胞吐作用和葡萄糖稳态的昼夜节律控制中的作用。


生物钟由负转录反馈环路编码，该环路通过尚未完全了解的分子程序来协调生理和行为。在这里，我们揭示了编码胰腺β细胞内肽能分泌调节因子的前mRNA的有节奏的全基因组选择性剪接（AS），这些调节因子在Clock ^-/−和Bmal1 ^-/− β细胞系中受到干扰。我们发现，RNA 结合蛋白 THRAP3（甲状腺激素受体相关蛋白 3）通过与外显子侧翼编码序列的外显子结合来调节昼夜节律时钟依赖性 AS，这些外显子在时钟突变型 β 细胞中更常被跳过，包括编码Cask （钙）的转录本。 /钙调蛋白依赖性丝氨酸蛋白激酶）和Madd （ MAP 激酶激活死亡结构域）。 THRAP3 的耗竭恢复了Cask和Madd长亚型的表达，并且通过在野生型胰岛中传递反义寡核苷酸来模拟这些转录物中的外显子跳跃，从而减少葡萄糖刺激的胰岛素分泌。最后，我们从饮食诱发肥胖的啮齿动物模型的胰岛中确定了与时钟突变体显着重叠的选择性剪接胞吐基因的共享网络。我们的结果确定了前 mRNA 选择性剪接在整个睡眠/觉醒周期的 β 细胞功能中的作用。