Targeted degradation of TOC1 by ZTL modulates circadian function in Arabidopsis thaliana
Targeted degradation of TOC1 by ZTL modulates circadian function in Arabidopsis thaliana
复制标题
DOI：
10.1038/nature02163
复制
发表时间：
2003-12-04
期刊：
影响因子：
64.8
通讯作者：
Kay, SA
中科院分区：
文献类型：
--
作者：
Más, P;Kim, WY;Kay, SA
昼夜节律性的潜在机制似乎在生物体中是保守的，并且是基于形成细胞振荡器(或时钟)的负转录反馈环(1，2)。蛋白质稳定性、磷酸化和亚细胞定位的昼夜变化也有助于这一时钟(1，2)的产生和维持。在植物中，有几个基因已被证明与昼夜节律系统密切相关(3，4)。然而，被提出的调控植物时钟的分子机制大多基于转录水平的调控(3，4)。在这里，我们提供了ZEITLUPE(ZTL)(5-7)在拟南芥(Thale Cress)CAB表达1(TOC1)(8，9)的定时定向降解中的作用的遗传和分子证据。ZTL-1突变取消了TOC1与ZTL的物理相互作用，导致TOC1蛋白表达的结构性水平。TOC1蛋白的暗依赖降解需要功能上的ZTL，并通过抑制蛋白小体途径来防止。我们的结果表明，TOC1-ZTL相互作用在控制TOC1蛋白的稳定性中起着重要作用，可能是时钟调节昼夜节律的机制之一。
The underlying mechanism of circadian rhythmicity appears to be conserved among organisms, and is based on negative transcriptional feedback loops forming a cellular oscillator ( or 'clock')(1,2). Circadian changes in protein stability, phosphorylation and subcellular localization also contribute to the generation and maintenance of this clock(1,2). In plants, several genes have been shown to be closely associated with the circadian system(3,4). However, the molecular mechanisms proposed to regulate the plant clock are mostly based on regulation at the transcriptional level(3,4). Here we provide genetic and molecular evidence for a role of ZEITLUPE (ZTL)(5-7) in the targeted degradation of TIMING OF CAB EXPRESSION 1 (TOC1)(8,9) in Arabidopsis thaliana (thale cress). The physical interaction of TOC1 with ZTL is abolished by the ztl-1 mutation, resulting in constitutive levels of TOC1 protein expression. The dark-dependent degradation of TOC1 protein requires functional ZTL, and is prevented by inhibiting the proteosome pathway. Our results show that the TOC1 - ZTL interaction is important in the control of TOC1 protein stability, and is probably responsible for the regulation of circadian period by the clock.