Characterization and dietary regulation of glutamate dehydrogenase in different ploidy fishes
Characterization and dietary regulation of glutamate dehydrogenase in different ploidy fishes
复制标题
不同倍性鱼类谷氨酸脱氢酶的特性及膳食调控
DOI：
10.1007/s00726-012-1313-z
复制
发表时间：
2012-12-01
期刊：
影响因子：
3.5
通讯作者：
Liu, Yun
中科院分区：
文献类型：
--
作者：
Liu, Zhen;Zhou, Yi;Liu, Yun
谷氨酸脱氢酶（GDH）在氨基酸脱氨基中发挥着至关重要的作用，并已被用作营养物质代谢的诱导剂。在本研究中，我们克隆并分析了二倍体（红鲫鱼）、三倍体和四倍体中的 GDH cDNA，并表征了它们在饮食处理后的表达谱。结果表明，三种倍体鱼类和其他脊椎动物的GDH序列具有很高的相似性。表达分析表明，GDH 在不同类型的鱼类中表现出独特的表达空间模式。三倍体和四倍体在心脏、肝脏、鳃、肌肉、前肠和中肠中的表达水平高于二倍体。 GDH 表达也受到发育调节，在囊胚期附近表达更强。母体 GDH 转录本首先从卵中检测到，其表达从原肠胚阶段下降到心跳阶段。成年三倍体在繁殖季节肝脏中 GDH 表达水平最高，这可能有助于其良好的食欲和快速生长。此外，与其他两种鱼类相比，三倍体表现出高生长率和过量的 GDH 表达。三倍体肝脏GDH酶活性也高于红鲫鱼和四倍体。此外，GDH 表达受膳食蛋白质水平的调节。用高蛋白或低蛋白饲料喂养的鱼表现出较高水平的 GDH 表达。总之，我们的结果首次证明不同倍体鱼类在发育、繁殖和非繁殖季节具有不同的 GDH mRNA 表达模式，以及饮食中不同蛋白质水平的饮食影响。这些数据表明丰富的 GDH 表达可能在三倍体的生长速率中发挥重要作用。
Glutamate dehydrogenase (GDH) plays a crucial role in amino acid deamination and has been used as an inductor of nutrients metabolism. In this study, we cloned and analyzed the GDH cDNAs in diploids (red crucian carp), triploids and tetraploids and characterized their expression profiles upon dietary treatments. Results showed a high sequence similarity of GDH among the three kinds of ploidy fishes and other vertebrates. Expression analysis revealed that GDH exhibited a distinct spatial pattern of expression in different types of fishes. The triploids and tetraploids had higher levels of expression than diploids in heart, liver, gill, muscle, fore-gut and mid-gut. The GDH expression was also developmentally regulated with a stronger expression around blastula stage. The maternal GDH transcripts were first detected from eggs and their expression dropped down from the gastrula stage to heart beat stage. Adult triploids showed the highest levels of GDH expression in liver during breeding season which may contribute to the good appetite and fast growth. In addition, triploids exhibited high growth rates and excess GDH expression compared with other two types of fishes. The liver GDH enzyme activities were also higher in triploids than red crucian carp and tetraploids. Moreover, GDH expression is regulated by dietary protein levels. Fish fed with either high or low protein diets showed higher levels of GDH expression. In summary, our results demonstrated for the first time that the different ploidy fishes had different patterns of GDH mRNA expression during development, breeding and non-breeding seasons, and as well dietary effects from different protein levels in diet. These data indicate that abundant GDH expression may play an important role in growth rates in triploids.