Feedback repression is required for mammalian circadian clock function
Feedback repression is required for mammalian circadian clock function
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DOI：
10.1038/ng1745
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发表时间：
2006-03-01
期刊：
影响因子：
30.8
通讯作者：
Hogenesch, JB
中科院分区：
文献类型：
--
作者：
Sato, TK;Yamada, RG;Hogenesch, JB
生物钟功能需要转录反馈抑制的直接证据一直难以捉摸。在这里，我们在哺乳动物细胞中开发了一种分子遗传筛选，以识别昼夜节律转录激活因子CLOCK和BMAL 1的突变体，这些突变体是从CRY介导的转录抑制中解偶联的。值得注意的是，CLOCK的PER-ARNT-SIM结构域和BMAL 1的C末端的突变通过减少与CRY的物理相互作用而导致协同不敏感性。这些突变蛋白在培养的成纤维细胞中的共表达引起了群体和单细胞测定中的细胞表型。这些数据表明，CLOCK/BMAL 1复合物活性的抑制是维持昼夜节律所必需的，并提供了哺乳动物时钟功能所需的转录反馈的正式证据。
Direct evidence for the requirement of transcriptional feedback repression in circadian clock function has been elusive. Here, we developed a molecular genetic screen in mammalian cells to identify mutants of the circadian transcriptional activators CLOCK and BMAL1, which were uncoupled from CRYPTOCHROME (CRY)- mediated transcriptional repression. Notably, mutations in the PER-ARNT-SIM domain of CLOCK and the C terminus of BMAL1 resulted in synergistic insensitivity through reduced physical interactions with CRY. Coexpression of these mutant proteins in cultured fibroblasts caused arrhythmic phenotypes in population and single-cell assays. These data demonstrate that CRY-mediated repression of the CLOCK/BMAL1 complex activity is required for maintenance of circadian rhythmicity and provide formal proof that transcriptional feedback is required for mammalian clock function.