Yoshii Taishi, Todo Takeshi, Wülbeck Corinna, Stanewsky Ralf, Helfrich-Förster Charlotte
Institute of Zoology, University of Regensburg, 93040 Regensburg, Germany.
J Comp Neurol. 2008 Jun 20;508(6):952-66. doi: 10.1002/cne.21702.
Cryptochrome (CRY) is intimately associated with the circadian clock of many organisms. In the fruit fly Drosophila melanogaster, CRY seems to be involved in photoreception as well as in the core clockwork. In spite of the critical role of CRY for the clock of Drosophila, it was not quite clear whether CRY is expressed in every clock cell. With the help of a new antibody and a mutant that lacks CRY, we show here that CRY is expressed in specific subsets of Drosophila's pacemaker neurons and in the photoreceptor cells of the compound eyes. In the pacemaker neurons, CRY levels and kinetics under light-dark cycles are quite different from each other. High-amplitude oscillations are observed in only three groups of clock neurons, suggesting that these three groups are strongly receptive to light. The different CRY kinetics may account for phase differences in oscillations of the clock proteins observed in these three groups in earlier studies. The molecular clock of the neurons that contain lower CRY levels or are completely CRY negative can still be synchronized by light, probably via intercellular communication with the CRY-positive neurons as well as via external photoreceptors.
隐花色素（CRY）与许多生物体的生物钟密切相关。在果蝇（Drosophila melanogaster）中，CRY似乎既参与光感受，也参与核心生物钟机制。尽管CRY对果蝇的生物钟起着关键作用，但CRY是否在每个生物钟细胞中表达尚不完全清楚。借助一种新抗体和一个缺乏CRY的突变体，我们在此表明，CRY在果蝇起搏器神经元的特定亚群以及复眼的光感受器细胞中表达。在起搏器神经元中，CRY水平和在明暗周期下的动力学彼此相当不同。仅在三组生物钟神经元中观察到高振幅振荡，这表明这三组对光强烈敏感。不同的CRY动力学可能解释了早期研究中在这三组中观察到的生物钟蛋白振荡的相位差异。CRY水平较低或完全为CRY阴性的神经元的分子生物钟仍可被光同步，可能是通过与CRY阳性神经元的细胞间通讯以及通过外部光感受器。
