Temperature adaptation of fish - molecular mechanisms involved and application

鲤鱼对环境温度的适应诱导了肌球蛋白重链基因的表达，而肌球蛋白重链基因在10 ℃和30 ℃下的表达量最高。鲤鱼在温度驯化后的生化变化中也观察到了细胞内的肌浆网和各种酶的变化。看来，鱼类动态地改变许多细胞成分，以响应环境温度。据认为，环境温度信号被传递到中枢神经系统，随后通过各种激素调节作用于基因表达。为了揭示鱼类温度适应的分子机制，并为工业应用提供依据，本研究克隆了鲤鱼10 ℃型和30 ℃型肌球蛋白重链异构体5'上游调控区，并对其结构进行了完整性分析，鉴定了MEF 2结合元件，并对MEF 2结合元件进行了结构分析。 ...更多信息 可能激活基因表达。此外，还发现青鳉肌球蛋白重链基因的5 '上游区域也参与了温度依赖性基因表达的调控，鲤鱼55 kDa胞质蛋白的表达水平随着低温的驯化而增加。该蛋白是线粒体FOF_1-ATPase的亚基之一，在30 ℃至10 ℃温度变化后，其含量增加了两倍。这种不同的表达依赖于驯化温度在转录水平上进行调节。不同的鱼类采集了霞浦湖全年定期和快速骨骼肌肌原纤维ATP酶活性测定。11月采集的鱼类线粒体膜电位活性最高，随后逐渐下降，在6、7月达到最低值。建立了利用电压敏感探针和荧光成像技术测定线粒体膜电位的分析方法。利用该方法成功地测定了鱼类线粒体膜电压相关势能随环境温度适应的变化。少

Carp acclimates to environmental temperature and induces genes encoding myosin heavy chain isoforms predominantly expressed for fish acclimated to 10 and 30 ℃. Such changes in biochemical changes in carp following temperature acclimation are also observed with intracellular apparatus such as sarcoplasmic reticulum and various enzymes. It seems that, fish alters dynamically many cellular components in response to environmental temperatures. It is considered that environmental temperature signals are transmitted to the central nervous system and subsequently act on gene expression via various hormonal regulations. The objective of this study was to disclose molecular mechanisms involved in temperature adaptation of fish and to utilize the results obtained for industrial application.The 5' upstream regulatory regions of the 10 ℃- and 30 ℃-type carp myosin heavy chain isoforms were cloned and determined for their structural integrity, resulting in identification of MEF2 binding element res … More ponsible for activation of gene expression. Furthermore, it was found that 5'-upstream regions of myosin heavy chain genes from medaka, another eurythermal fish, also participate in such regulation for temperature-dependent gene expression.Carp increased expression levels of 55 kDa cytosolic protein in association with acclimation to cold temperature. This protein was found to be one of subunits of mitochondrial FOF1-ATPase and increased its quantities two times following temperature shift from 30 ℃ to 10 ℃. Such different expression depending on acclimation temperature was regulated at the transcription level.Various fish species were collected from Kasumigaura Lake periodically all around the year and determined for ATPase activity of fast skeletal muscle myofibrils. The activity was the highest with fish collected in November and decreased gradually reaching the minimum value in June and July.Analytical method to determine mitochondrial membrane voltage was developed by using voltage-sensitive probe and fluorescence imaging. Changes in voltage-associated potential energy of mitochondrial membranes following adaptation to environmental temperatures of fish were successfully measured by this method. Less