Probing entrainment of Ostreococcus tauri circadian clock by green and blue light through a mathematical modeling approach
Probing entrainment of Ostreococcus tauri circadian clock by green and blue light through a mathematical modeling approach
复制标题
通过数学建模方法探讨绿光和蓝光对金牛座骨球菌生物钟的夹带作用
作者：
Quentin Thommen;Benjamin Pfeuty;P. Schatt;Amandine Bijoux;F. Bouget;M. Lefranc
大多数生物体预测每日环境变化并协调细胞功能，这要归功于昼夜周期的强大生物钟，尽管光强度因天气或季节变化而波动。由于海水对不同波长的不同吸收，海洋生物的光谱组成也会随着深度的变化而波动。因此，研究光输入通路如何有助于生物钟的稳定性是很重要的。牛链球菌是一种单细胞微浮游海洋绿藻，基因组复杂性低，细胞结构简单，是一种很有前途的系统生物学模式生物。功能和建模方法表明，在广泛的条件下获得的大部分实验数据都是基于拟南芥TOC1和CCA1时钟基因的同源基因的核心昼夜节律振荡器。一些证据表明，光输入途径(S)由两组分的信号系统(TCS)组成，该信号系统由仅有的两个组氨酸激酶(HK)控制。LOV-HK是一种受昼夜节律控制的蓝光感受器，是生物钟功能所必需的。视紫红质-HK(Rhod-HK)的参与也是可能的，因为视紫红质光感受器在动物生物钟中介导蓝光到绿光的输入。在这里，我们利用一个结合TCS假说的数学模型来探讨LOV-HK和Rhod-HK在调节光输入到TOC1-CCA1振荡器中的作用。该模型与代表蓝光或绿光下多种环境条件的时钟基因表达时间序列一致，表征了光/暗循环的夹带、恒光下的自由运行和重置。实验和理论结果表明，蓝光和绿光都能使金牛座生物钟复位。此外，我们的数学分析表明，Rhod-HK是一个蓝绿光受体，与LOV-HK一起驱动时钟。
Most organisms anticipate daily environmental variations and orchestrate cellular functions thanks to a circadian clock which entrains robustly to the day/night cycle, despite fluctuations in light intensity due to weather or seasonal variations. Marine organisms are also subjected to fluctuations in light spectral composition as their depth varies, due to differential absorption of different wavelengths by sea water. Studying how light input pathways contribute to circadian clock robustness is therefore important. Ostreococcus tauri, a unicellular picoplanktonic marine green alga with low genomic complexity and simple cellular organization, has become a promising model organism for systems biology. Functional and modeling approaches have shown that a core circadian oscillator based on orthologs of Arabidopsis TOC1 and CCA1 clock genes accounts for most experimental data acquired under a wide range of conditions. Some evidence points at putative light input pathway(s) consisting of a two-component signaling system (TCS) controlled by the only two histidine kinases (HK) of O. tauri. LOV-HK is a blue light photoreceptor under circadian control, that is required for circadian clock function. An involvement of Rhodopsin-HK (Rhod-HK) is also conceivable since rhodopsin photoreceptors mediate blue to green light input in animal circadian clocks. Here, we probe the role of LOV-HK and Rhod-HK in mediating light input to the TOC1-CCA1 oscillator using a mathematical model incorporating the TCS hypothesis. This model agrees with clock gene expression time series representative of multiple environmental conditions in blue or green light, characterizing entrainment by light/dark cycles, free-running in constant light, and resetting. Experimental and theoretical results indicate that both blue and green light can reset O. tauri circadian clock. Moreover, our mathematical analysis suggests that Rhod-HK is a blue-green light receptor and drives the clock together with LOV-HK.
影响因子：
4.8
作者：
Luck, Meike;Mathes, Tilo;Hegemann, Peter
通讯作者：
Hegemann, Peter
影响因子：
11.6
作者：
Beel, Benedikt;Prager, Katja;Mittag, Maria
通讯作者：
Mittag, Maria