Myers M P, Wager-Smith K, Rothenfluh-Hilfiker A, Young M W
Howard Hughes Medical Institute, New York, NY 10021, USA.
Science. 1996 Mar 22;271(5256):1736-40. doi: 10.1126/science.271.5256.1736.
Two genes, period (per) and timeless (tim), are required for production of circadian rhythms in Drosophila. The proteins encoded by these genes (PER and TIM) physically interact, and the timing of their association and nuclear localization is believed to promote cycles of per and tim transcription through an autoregulatory feedback loop. Here it is shown that TIM protein may also couple this molecular pacemaker to the environment, because TIM is rapidly degraded after exposure to light. TIM accumulated rhythmically in nuclei of eyes and in pacemaker cells of the brain. The phase of these rhythms was differentially advanced or delayed by light pulses delivered at different times of day, corresponding with phase shifts induced in the behavioral rhythms.
周期基因（per）和无时间基因（tim）是果蝇产生昼夜节律所必需的两个基因。这些基因编码的蛋白质（PER和TIM）会发生物理相互作用，并且它们结合和核定位的时间被认为通过一个自动调节反馈环促进per和tim的转录循环。本文表明，TIM蛋白还可能将这个分子生物钟与环境联系起来，因为暴露于光线下后，TIM会迅速降解。TIM有节奏地在眼睛的细胞核和大脑的起搏细胞中积累。这些节律的相位会因在一天中不同时间给予的光脉冲而不同程度地提前或延迟，这与行为节律中诱导的相位变化相对应。
