Abstract：Abstract: Cryptochrome (Cry) is a flavoprotein that regulates gene expression and entrains circadian rhythms. It has a high degree of homology with the photolyase. Drosophila cryptochrome (dCry) is type I animal Cry. It functions as a photoreceptor in Drosophila circadian clock. In structure, dCry contains a photolyase homology region at N terminal, and a C-terminal tail. The photolyase homology region binds an flavin adenine dinucleotide (FAD) cofactor, and has an electron transfer pathway consisting of a tryptophan triad (or tetrad). The C-terminal tail of dCry binds to a pocket structure at the photolyase homology region, in a manner resembling that substrate binds to photolyase. Under illumination, the bound FAD cofactor can accept an electron transferred by the tryptophan triad (or tetrad), and be photoreduced. Then, the C-terminal tail may eject from the pocket structure, leading to the conformational changes of dCry, and signal is transmitted to downstream by protein interaction. Hitherto, the mechanism of photoreception and signaling state of dCry are still controversial. In one model, the oxidized state of dCry is converted to the anion radical state upon photoreduction, which is the possible signaling state of dCry; in the alternative mode, dCry contains FAD•– in the ground state, the excitation of FAD•– by light to FAD•–* causes the conformational change, which is responsible for signaling. Nevertheless, the experiments on action spectrum of dCry revealed that signaling state of dCry may not be restricted with the photoreduction of FAD, and lights at different wavelengths may have different effects on dCry. Here, the functions of dCry in the entrainment of circadian clock and its structural features are reviewed, as well as the possible photoreception mechanisms and the signaling states of it, to provide theoretical reference for further exploration on the physiological functions and action mechanisms of dCry.
Key words: Drosophila cryptochrome; flavoprotein; circadian clock; photoreception; action spectrum
引用本文:
姚鹏程，郑 伟，周志强，徐 蕾. 果蝇隐（花）色素光感受机理的研究现状[J]. 激光生物学报, 2020, 29(5): 399-404.
YAO Pengcheng, ZHENG Wei, ZHOU Zhiqiang, XU Lei. Advances in the Photoreception of Drosophila Cryptochrome. journal1, 2020, 29(5): 399-404.
