The relationship between FRQ-protein stability and temperature compensation in the Neurospora circadian clock.
The relationship between FRQ-protein stability and temperature compensation in the Neurospora circadian clock.
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DOI：
10.1073/pnas.0505137102
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发表时间：
2005-12
影响因子：
11.1
通讯作者：
P. Ruoff;J. Loros;J. Dunlap
中科院分区：
文献类型：
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作者：
P. Ruoff;J. Loros;J. Dunlap
温度补偿是所有生物钟的重要特性。在粗糙脉孢菌中，FRQ蛋白对频率（frq）基因转录的负反馈调节在生物体的昼夜节律起搏器中起着核心作用。早期的模型计算预测，FRQ的稳定性应该决定脉孢菌的昼夜节律的周期长度以及节律的温度补偿。在这里，我们报告实验FRQ蛋白在20摄氏度和25摄氏度的FRQ突变体的稳定性，并估计突变体FRQ蛋白降解的总活化能。结果与早期的模型预测一致，即，脉孢菌昼夜节律的温度补偿是一个高度调节的过程，其中FRQ的稳定性是决定脉孢菌昼夜节律周期以及时钟温度补偿的重要因素。frq7和frq（S513I）突变体的温度补偿的部分损失可以描述一个简单的负反馈模型（古德温振荡器）时，这些突变体的FRQ降解的实验获得的活化能被纳入模型。
Temperature compensation is an important property of all biological clocks. In Neurospora crassa, negative-feedback regulation on the frequency (frq) gene's transcription by the FRQ protein plays a central role in the organism's circadian pacemaker. Earlier model calculations predicted that the stability of FRQ should determine the period length of Neurospora's circadian rhythm as well as the rhythm's temperature compensation. Here, we report experimental FRQ protein stabilities in frq mutants at 20 degrees C and 25 degrees C, and estimates of overall activation energies for mutant FRQ protein degradation. The results are consistent with earlier model predictions, i.e., temperature compensation of Neurospora's circadian rhythm is a highly regulated process where the stability of FRQ is an important factor in determining Neurospora's circadian period as well as the clock's temperature compensation. The partial loss of temperature compensation in frq7 and frq(S513I) mutants can be described by a simple negative-feedback model (the Goodwin oscillator) when the experimentally obtained activation energies of FRQ degradation for theses mutants are incorporated into the model.