Molecular Genetics Section, Pacific Biological Station, 3190 Hammond Bay Road, Fisheries and Oceans Canada, Nanaimo, BC, Canada V9T 6N7.
Comp Biochem Physiol Part D Genomics Proteomics. 2009 Jun;4(2):75-89. doi: 10.1016/j.cbd.2008.11.002. Epub 2008 Dec 6.
A large-scale functional genomics study revealed shifting metabolic processes in white muscle during the final 1300 km migration of wild sockeye salmon to their spawning grounds in the Fraser River, British Columbia. In 2006, Lower Adams stock sockeye salmon ceased feeding after passing the Queen Charlotte Islands, 850 km from the Fraser River. Enhanced protein turnover and reduced transcription of actin, muscle contractile and heme-related proteins were early starvation responses in saltwater. Arrival to the estuarine environment triggered massive protein turnover through induction of proteasomal and lysosomal proteolysis and protein biosynthesis, and a shift from anaerobic glycolysis to oxidative phosphorylation. Response to entry into freshwater was modest, with up-regulation of heat shock proteins and nitric oxide biosynthesis. High river temperatures resulted in a strong defense/immune response and high mortalities in 50% of fish. Arrival to the spawning grounds triggered further up-regulation of oxidative phosphorylation and proteolysis, down-regulation of protein biosynthesis and helicase activity, and continued down-regulation of muscle proteins and most glycolytic enzymes. However, sharp up-regulation of PFK-I indicated induction of glycolytic potential at the spawning grounds. The identification of potential environmental cues triggering genome-wide transcriptional shifts in white muscle associated with migration and the strong activation of proteasomal proteolysis were both novel findings.
一项大规模的功能基因组学研究揭示了野生三文鱼在最后 1300 公里洄游到不列颠哥伦比亚弗雷泽河产卵地的过程中，白肌肉代谢过程的变化。2006 年，在距离弗雷泽河 850 公里的夏洛特皇后群岛，下亚当斯种群的红大麻哈鱼停止进食。在海水中，增强的蛋白质周转和肌动蛋白、肌肉收缩和血红素相关蛋白的转录减少是早期饥饿反应。进入河口环境会通过诱导蛋白酶体和溶酶体蛋白水解和蛋白质生物合成，以及从无氧糖酵解向氧化磷酸化的转变，引发大量的蛋白质周转。进入淡水的反应适度，热休克蛋白和一氧化氮生物合成上调。高河水温度导致 50%的鱼类出现强烈的防御/免疫反应和高死亡率。到达产卵地进一步上调氧化磷酸化和蛋白水解，下调蛋白质生物合成和解旋酶活性，并继续下调肌肉蛋白和大多数糖酵解酶。然而，PFK-I 的急剧上调表明在产卵地诱导了糖酵解能力。鉴定出与洄游相关的白肌肉中触发全基因组转录变化的潜在环境线索，以及蛋白酶体蛋白水解的强烈激活，都是新的发现。
