Do differences in the activities of carbohydrate metabolism enzymes between Lake Whitefish ecotypes match predictions from transcriptomic studies?
Do differences in the activities of carbohydrate metabolism enzymes between Lake Whitefish ecotypes match predictions from transcriptomic studies?
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DOI：
10.1016/j.cbpb.2017.08.001
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发表时间：
2018-10-01
影响因子：
2.2
通讯作者：
Bernatchez, Louis
中科院分区：
文献类型：
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作者：
Dalziel, Anne C.;Laporte, Martin;Bernatchez, Louis
转录学研究正在促进寻找自然种群适应的分子基础，但这些mRNA含量的差异对动物生理学的影响往往是未知的。确定分子变化是否有可能影响动物的生理和性能的一种方法是测试生物组织的更高水平上的相关变化，包括酶的活性。在这里，我们测量碳水化合物代谢酶的活性，以测试先前报道的‘矮小’和‘正常’湖白鱼生态型之间的遗传和转录差异是否与肝脏和骨骼肌酶活性(以最大速率衡量)的相应变化有关。我们使用实验室饲养的相同种群的鱼作为先前的转录组研究，发现白色肌肉mRNA含量是糖酵解和糖原代谢酶活性的良好预测因子，并且矮小白鱼进化出比正常白鱼更高的活性。然而，在先前的研究中发现，不同生态型之间的肝脏mRNA含量的差异与酶活性的类似变化无关。例如，与正常白鱼相比，矮小白鱼的酶活性较低，但两种糖酵解酶的转录丰度较高。总体而言，我们发现转录学研究成功地突出了酶活性的进化变异，但并不总是在预测的方向上，这表明各种组织特异性的调节机制有助于白鱼湖能量代谢的进化。
Transcriptomic studies are facilitating the search for the molecular bases of adaptation in natural populations, but the impact of these differences in mRNA content on animal physiology are often unknown. One way to determine if molecular changes have the potential to influence animal physiology and performance is to test for correlated changes at higher levels of biological organization, including enzyme activity. Here, we measure the activities of carbohydrate metabolism enzymes to test if previously documented genetic and transcriptomic variation between 'dwarf' and 'normal' Lake Whitefish ecotypes are associated with corresponding changes in enzyme activity (measured as maximal rate, V-max) in liver and skeletal muscle. We use laboratory-reared fish from the same populations as prior transcriptomic studies and find that white muscle mRNA content is a good predictor of glycolytic and glycogen metabolism enzyme activity, and dwarf whitefish have evolved higher activities than normal whitefish. However, the differences in hepatic mRNA content found between ecotypes in prior studies are not associated with comparable changes in enzyme activity. For example, dwarf whitefish have lower enzyme activities, but higher transcript abundances for two glycolytic enzymes compared to normal whitefish. Overall, we find that transcriptomic studies successfully highlight evolutionary variation in enzyme activities, but not always in the direction predicted, indicating that a variety of tissue-specific regulatory mechanisms contributed to the evolution of energy metabolism in Lake Whitefish.