From the Center for Circadian Clocks, Medical College, Soochow University, Suzhou 215123, China.
J Biol Chem. 2013 Oct 25;288(43):31002-9. doi: 10.1074/jbc.M113.494120. Epub 2013 Sep 12.
In the Neurospora circadian negative feedback loop, white collar 1 (WC-1) and WC-2 form the WC complex that activates frequency (frq) transcription. Here we show that Not1 is a WC-interacting protein and is important for maintaining WC levels. The not1 transcript displays a circadian oscillation with a similar phase as frq. Down-regulation of not1 leads to low levels of WC-1 and WC-2 and a delayed circadian phase as a result of increased protein degradation and increased WC activity. Protein purification of Not1 shows that it is part of the Neurospora Ccr4-Not complex. ccr4 is a clock-controlled gene and is regulated directly by the WC complex. Down-regulation of ccr4 results in a phase delay and period lengthening of the clock. Together, our findings suggest that the Ccr4-Not complex participates in the Neurospora clock function by interacting with and regulating the WC complex.
在Neurospora 生物钟负反馈回路中，白色领结 1（WC-1）和 WC-2 形成 WC 复合物，激活频率（frq）转录。在这里，我们表明 Not1 是一种 WC 相互作用蛋白，对于维持 WC 水平很重要。not1 转录本显示出与 frq 相似相位的生物钟振荡。not1 的下调导致 WC-1 和 WC-2 水平降低，并且由于蛋白质降解增加和 WC 活性增加，生物钟相位延迟。Not1 的蛋白纯化表明它是 Neurospora Ccr4-Not 复合物的一部分。ccr4 是一个生物钟控制的基因，直接受 WC 复合物调控。ccr4 的下调导致生物钟相位延迟和周期延长。总之，我们的研究结果表明，Ccr4-Not 复合物通过与 WC 复合物相互作用和调节参与 Neurospora 生物钟功能。
