A temperature-dependent timing mechanism is involved in the circadian system that drives locomotor rhythms in the fruit fly Drosophila melanogaster
A temperature-dependent timing mechanism is involved in the circadian system that drives locomotor rhythms in the fruit fly Drosophila melanogaster
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DOI：
10.2108/zsj.19.841
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发表时间：
2002-08-01
影响因子：
0.9
通讯作者：
Tomioka, K
中科院分区：
文献类型：
--
作者：
Yoshii, T;Sakamoto, M;Tomioka, K
黑腹果蝇的生物钟被认为包括周期基因的节律性表达。然而，最近的研究表明，PER较少的振荡也参与了昼夜运动节奏的调节。在本研究中，我们使用携带PER(01)、Tim(01)、dClk(JRK)或Cyc(01)的心律失常时钟突变果蝇来检测可能的无PER振荡的存在和性质，这些突变体缺乏节律性PER表达。当给出25℃和30℃不同周期(T=8与32小时)的温度周期时，在恒光(LL)中，野生型(广州-S)果蝇在很大范围内(T=8与32小时)表现出运动节律，而在恒暗(DD)中仅T=24小时。突变果蝇在LL和DD下均表现出与给定周期同步的节律。在PER(01)和TIM(01)果蝇中，主峰的相位随Dd的Ts而略有变化，而在DClk(JRK)和Cyc(01)果蝇中则没有变化。当它们在DD下从恒温转变为温度循环时，需要几个循环才能在PER(01)和TIM(01)苍蝇中建立明显的温度夹带。这些结果表明，PER(01)和TIM(01)果蝇具有温度可携带的弱振荡机制，而PER(01)和TIM(01)的振荡机制可能需要dClk和Cyc。此外，PER(01)和TIM(01)果蝇在DD中由热活性转变为LL中的低温活性，而dClk(JRK)和Cyc(01)则不变。因此，我们认为dClk和cyc也参与了PER(01)和Tim(01)果蝇的光相关温度偏好的决定。
The circadian clock of Drosophila melanogasteris thought to include rhythmic expression of period gene. Recent studies suggested, however, that a per-less oscillation is also involved in the regulation of circadian locomotor rhythms. In the present study, we examined the existence and the property of the possible per-less oscillation using arrhythmic clock mutant flies carrying per(01), tim(01), dClk(Jrk) or cyc(01), which lack rhythmic per expression. When temperature cycles consisting of 25 C and 30 C with various periods (T=8similar to32 hr) were given, wild-type (Canton-S) flies showed locomotor rhythms entrained to temperature cycles over a wide range of period (T=8similar to32 hr) in constant light (LL) while only to T=24 hr in constant darkness (DD). The mutant flies showed rhythms synchronizing with the given cycle both under LL and DD. In per(01) and tim(01) flies, the phase of a major peak slightly changed dependent on Ts in DD, while it did not in dClk(Jrk) and cyc(01) flies. When they were transferred from a constant temperature to a temperature cycle under DD, several cycles were necessary to establish a clear temperature entrainment in per(01) and tim(01) flies. These results suggest that per(01) and tim(01) flies have a temperature-entrainable weak oscillatory mechanism and that the per-less oscillatory mechanism may require dClk and cyc. In addition, per(01) and tim(01) flies changed from thermoactive in DD to cryoactive in LL, while dClk(Jrk) and cyc(01) flies did not. It is thus suggested that dClk and cyc are also involved in determining the light-associated temperature preference in per(01) and tim(01) flies.