Matallana-Surget Sabine, Geron Augustin, Decroo Corentin, Wattiez Ruddy
Division of Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK.
Proteomic and Microbiology Department, University of Mons, B-7000 Mons, Belgium.
Int J Mol Sci. 2024 Mar 2;25(5):2934. doi: 10.3390/ijms25052934.
Circadian rhythms, characterized by approximately 24 h cycles, play a pivotal role in enabling various organisms to synchronize their biological activities with daily variations. While ubiquitous in Eukaryotes, circadian clocks remain exclusively characterized in among Prokaryotes. These rhythms are regulated by a core oscillator, which is controlled by a cluster of three genes: , , and . Interestingly, recent studies revealed rhythmic activities, potentially tied to a circadian clock, in other Prokaryotes, including purple bacteria such as , known for its applications in fuel and plastic bioproduction. However, the pivotal question of how light and dark cycles influence protein dynamics and the expression of putative circadian clock genes remains unexplored in purple non-sulfur bacteria. Unraveling the regulation of these molecular clocks holds the key to unlocking optimal conditions for harnessing the biotechnological potential of . Understanding how its proteome responds to different light regimes-whether under continuous light or alternating light and dark cycles-could pave the way for precisely fine-tuning bioproduction processes. Here, we report for the first time the expressed proteome of grown under continuous light versus light and dark cycle conditions using a shotgun proteomic analysis. In addition, we measured the impact of light regimes on the expression of four putative circadian clock genes (, , , ) at the transcriptional and translational levels using RT-qPCR and targeted proteomic (MRM-MS), respectively. The data revealed significant effects of light conditions on the overall differential regulation of the proteome, particularly during the early growth stages. Notably, several proteins were found to be differentially regulated during the light or dark period, thus impacting crucial biological processes such as energy conversion pathways and the general stress response. Furthermore, our study unveiled distinct regulation of the four genes at both the mRNA and protein levels in response to varying light conditions. Deciphering the impact of the diel cycle on purple bacteria not only enhances our understanding of their ecology but also holds promise for optimizing their applications in biotechnology, providing valuable insights into the origin and evolution of prokaryotic clock mechanisms.
昼夜节律以大约24小时的周期为特征，在使各种生物体将其生物活动与日常变化同步方面发挥着关键作用。虽然在真核生物中普遍存在，但昼夜节律钟在原核生物中仍未得到充分表征。这些节律由一个核心振荡器调节，该振荡器由一组三个基因控制： 、 和 。有趣的是，最近的研究揭示了其他原核生物中的节律活动，可能与昼夜节律钟有关，包括紫色细菌，如 ，它在燃料和塑料生物生产中具有应用价值。然而，在紫色非硫细菌中，光暗循环如何影响蛋白质动态和假定的昼夜节律钟基因的表达这一关键问题仍未得到探索。解开这些分子钟的调控机制是释放 生物技术潜力的最佳条件的关键。了解其蛋白质组如何响应不同的光照条件——无论是在持续光照还是交替光照和黑暗循环下——可以为精确微调生物生产过程铺平道路。在这里，我们首次使用鸟枪法蛋白质组分析报告了在持续光照与光照和黑暗循环条件下生长的 的表达蛋白质组。此外，我们分别使用RT-qPCR和靶向蛋白质组学（MRM-MS）在转录和翻译水平上测量了光照条件对四个假定的昼夜节律钟基因（ 、 、 、 ）表达的影响。数据显示光照条件对蛋白质组的整体差异调节有显著影响，特别是在早期生长阶段。值得注意的是，发现几种蛋白质在光照或黑暗时期受到差异调节，从而影响关键的生物过程，如能量转换途径和一般应激反应。此外，我们的研究揭示了四个 基因在mRNA和蛋白质水平上对不同光照条件的不同调节。解读昼夜循环对紫色细菌产生的影响不仅能增进我们对其生态学的理解，还有望优化它们在生物技术中的应用，为原核生物钟机制的起源和进化提供有价值的见解。
