Oku Hiromi, Tokuda Masaharu, Matsunari Hiroyuki, Furuita Hirofumi, Murashita Koji, Yamamoto Takeshi
National Research Institute of Aquaculture, Tamaki Station, Tamaki, Mie, 519-0423, Japan,
Fish Physiol Biochem. 2014 Dec;40(6):1757-69. doi: 10.1007/s10695-014-9965-0. Epub 2014 Aug 2.
To characterize thermal-responsive genes in fish, firstly, juvenile rainbow trout were reared in four different temperature conditions (average temperatures were 10, 14, 18, and 22 °C, respectively) and differentially expressed genes were identified. Gene expression in the liver was analyzed by the differential display method, followed by validation using real-time PCR. Subsequently, to examine whether the identified genes show heritable differences, the gene expression levels were compared among juveniles of three genetically distinct lines of rainbow trout (a strain and two closed colonies) by rearing at two different temperature conditions (average 14 and 22 °C). By rearing at 22 °C, growth retardation was observed compared with fish reared at 14 and 18 °C, and six genes were identified as differentially expressed genes in response to the rearing temperature in the gene expression analyses. With the increase in rearing temperature, gene expressions of a complement C1q and two ribosomal proteins were significantly up-regulated. On the other hand, three metabolic genes (betaine homocysteine methyltransferase, triosephosphate isomerase, and glucose-6-phosphatase) were down-regulated, indicating a metabolic depression due to high temperature. In the subsequent analyses, in response to the rearing temperature (14 and 22 °C), there was a trend that the complement C1q and glucose-6-phosphatase genes showed different expression patterns among the three rainbow trout lines, suggesting heritable differences in these genes. Our study provides information on thermal-responsive genes in fish, and we anticipate it will facilitate further investigation in the thermal biology of fish.
为了鉴定鱼类中的热响应基因，首先，将虹鳟幼鱼饲养在四种不同温度条件下（平均温度分别为10、14、18和22°C），并鉴定差异表达基因。通过差异显示法分析肝脏中的基因表达，随后使用实时PCR进行验证。随后，为了检查所鉴定的基因是否表现出遗传差异，通过在两种不同温度条件下（平均14和22°C）饲养，比较了三个遗传上不同品系的虹鳟幼鱼（一个品系和两个封闭群体）之间的基因表达水平。与在14和18°C饲养的鱼相比，在22°C饲养时观察到生长迟缓，并且在基因表达分析中鉴定出六个基因作为对饲养温度有响应的差异表达基因。随着饲养温度的升高，补体C1q和两种核糖体蛋白的基因表达显著上调。另一方面，三个代谢基因（甜菜碱同型半胱氨酸甲基转移酶、磷酸丙糖异构酶和葡萄糖-6-磷酸酶）被下调，表明高温导致代谢抑制。在随后的分析中，响应于饲养温度（14和22°C），补体C1q和葡萄糖-6-磷酸酶基因在三个虹鳟品系中呈现出不同的表达模式，这表明这些基因存在遗传差异。我们的研究提供了关于鱼类热响应基因的信息，并且我们预计这将有助于进一步研究鱼类的热生物学。
