Department of Physiology, Faculty of Biology, Regional Campus of International Excellence Campus Mare Nostrum, University of Murcia, 30100, Murcia, Spain.
Comp Biochem Physiol A Mol Integr Physiol. 2012 Nov;163(3-4):364-71. doi: 10.1016/j.cbpa.2012.07.004. Epub 2012 Jul 25.
Biological rhythms are driven by circadian oscillators, which are ultimately controlled by the cyclic expression of clock genes. Cryptochromes (CRY), blue light photoreceptors, belong to the negative elements of the transcriptional feedback loop into the molecular clock. This paper describes the cloning and characterization of two cryptochromes (cry1 and 2) in European seabass, which is considered an interesting chronobiology model due to its dual (diurnal/nocturnal) behavior. The cloned cDNA fragments encoded for two proteins of 567 and 668 amino acids, which included the FAD-binding and the DNA-photolyase domains. Moreover, both proteins had a high homology with cryptochrome proteins (Cry) of other teleost fish. These cry1 and 2 genes were expressed in several tissues of seabass (brain, liver, heart, retina, muscle, spleen, gill and intestine). In addition, the daily expression of cry1 was rhythmic in brain, heart and liver with the acrophase around ZT 03:15 h (after the onset of lights). Similarly, the cry2 daily expression was rhythmic in liver, peaking at ZT 03:28 h, whereas in brain the acrophase was at ZT 11:08 h (shortly prior to the offset of lights). These findings provide new elements to help understanding the functioning of the molecular clock of seabass.
生物节律由生物钟振荡器驱动，而生物钟振荡器最终受时钟基因的周期性表达所控制。隐花色素（CRY）是蓝光光受体，属于分子钟转录反馈环的负调控元件。本研究描述了欧洲鲈鱼两种隐花色素（cry1 和 2）的克隆和特征，欧洲鲈鱼由于其昼夜（白天/夜间）双重行为，被认为是一个有趣的生物钟模型。克隆的 cDNA 片段编码了两种 567 和 668 个氨基酸的蛋白质，它们包含 FAD 结合和 DNA 光裂合酶结构域。此外，这两种蛋白质与其他硬骨鱼的隐花色素蛋白（Cry）具有高度同源性。cry1 和 2 基因在鲈鱼的几种组织（大脑、肝脏、心脏、视网膜、肌肉、脾脏、鳃和肠）中表达。此外，cry1 在大脑、心脏和肝脏中的表达呈昼夜节律，峰值出现在 ZT 03:15 h（光照开始后）。同样，cry2 的每日表达在肝脏中呈节律性，峰值出现在 ZT 03:28 h，而在大脑中的峰值出现在 ZT 11:08 h（在光照结束前不久）。这些发现为帮助理解鲈鱼分子钟的功能提供了新的元素。
