Steinlechner Stephan, Jacobmeier Birgit, Scherbarth Frank, Dernbach Haiko, Kruse Friederike, Albrecht Urs
School of Veterinary Medicine of Hannover, Germany.
J Biol Rhythms. 2002 Jun;17(3):202-9. doi: 10.1177/074873040201700303.
The Per1 and Per2 genes are components of the mammalian circadian clock. Mutations in these genes alter phase resetting in response to a nocturnal light pulse, and Per2 mutant mice are known to become arrhythmic in constant darkness. We show that under constant light conditions, Per2 mutant mice exhibit robust activity rhythms as well as body temperature rhythms with a period length that is less than 24 h. In Per1 mutants, the period length of both activity and body temperature rhythms is longer than 24 h in constant light. Per1 mutants prolong their period length (tao) when illuminance is increased, whereas Per2 mutants shorten their endogenous period. Additionally, the authors show that the circadian pattern of Per1 and Per2 gene expression in mice is modified under different photoperiods and that there is a mutual influence of these genes on their timing of expression. We propose that, in mice, the phase relationship between Per1 and Per2 gene expression might be critical for transducing day length information to the organism. Per1 could be part of a morning oscillator tracking dawn, and Per2 could be part of an evening oscillator tracking dusk.
Per1和Per2基因是哺乳动物生物钟的组成部分。这些基因的突变会改变对夜间光脉冲的相位重置，并且已知Per2突变小鼠在持续黑暗中会变得无节律。我们发现，在持续光照条件下，Per2突变小鼠表现出强劲的活动节律以及体温节律，其周期长度小于24小时。在Per1突变体中，持续光照下活动和体温节律的周期长度均长于24小时。当光照强度增加时，Per1突变体延长其周期长度（τ），而Per2突变体缩短其内源性周期。此外，作者表明，在不同光周期下小鼠中Per1和Per2基因表达的昼夜模式会发生改变，并且这些基因在其表达时间上存在相互影响。我们提出，在小鼠中，Per1和Per2基因表达之间的相位关系可能对于将日长信息传递给生物体至关重要。Per1可能是追踪黎明的早晨振荡器的一部分，而Per2可能是追踪黄昏的傍晚振荡器的一部分。
