Department of Marine Biology and Aquaculture, Instituto de Ciencias Marinas de Andalucía, ICMAN-CSIC, 11519, Cádiz, Spain.
Nutrigenomics and Fish Growth Endocrinology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595, Castellón, Spain.
Sci Rep. 2017 Oct 11;7(1):12943. doi: 10.1038/s41598-017-13514-w.
The regulation of circadian gene expression remains largely unknown in farmed fish larvae. In this study, a high-density oligonucleotide microarray was used to examine the daily expression of 13,939 unique genes in whole gilthead sea bream (Sparus aurata) larvae with fast growth potentiality. Up to 2,229 genes were differentially expressed, and the first two components of Principal Component Analysis explained more than 81% of the total variance. Clustering analysis of differentially expressed genes identified 4 major clusters that were triggered sequentially, with a maximum expression at 0 h, 3 h, 9-15 h and 18-21 h zeitgeber time. Various core clock genes (per1, per2, per3, bmal1, cry1, cry2, clock) were identified in clusters 1-3, and their expression was significantly correlated with several genes in each cluster. Functional analysis revealed a daily consecutive activation of canonical pathways related to phototransduction, intermediary metabolism, development, chromatin remodeling, and cell cycle regulation. This daily transcriptome of whole larvae resembles a cell cycle (G1/S, G2/M, and M/G1 transitions) in synchronization with multicellular processes, such as neuromuscular development. This study supports that the actively feeding fish larval transcriptome is temporally organized in a 24-h cycle, likely for maximizing growth and development.
养殖鱼类幼体的生物钟基因表达调控仍知之甚少。本研究使用高密度寡核苷酸微阵列，检测了生长速度快的金头鲷（Sparus aurata）幼体的 13939 个独特基因的每日表达情况。多达 2229 个基因差异表达，主成分分析的前两个分量解释了超过 81%的总方差。差异表达基因聚类分析鉴定出 4 个主要聚类，依次触发，在 zeitgeber 时间 0h、3h、9-15h 和 18-21h 时达到最大值。在聚类 1-3 中鉴定出各种核心生物钟基因（per1、per2、per3、bmal1、cry1、cry2、clock），它们的表达与每个聚类中的几个基因显著相关。功能分析显示，与光转导、中间代谢、发育、染色质重塑和细胞周期调控相关的经典途径呈每日连续激活。整个幼虫的这种每日转录组类似于细胞周期（G1/S、G2/M 和 M/G1 转换），与神经肌肉发育等多细胞过程同步。本研究表明，活跃摄食的鱼类幼体转录组在 24 小时周期内进行时间组织，可能是为了最大限度地促进生长和发育。
