Temperature adaptation of fish - molecular mechanisms involved and application

鲤鱼适应环境温度，诱导的肌球蛋白重链异构体基因主要表达于适应10℃和30℃的鱼。温度驯化后鲤鱼的生化变化也可以通过胞内器官如肌浆网和各种酶观察到。鱼类似乎根据环境温度动态改变了许多细胞成分。外界认为，环境温度信号通过各种激素调控传递到中枢神经系统，进而作用于基因表达。本研究的目的是揭示鱼类温度适应的分子机制，并将所获得的结果用于工业应用。克隆了10℃型和30℃型鲤鱼肌球蛋白重链亚型的5′上游调控区，并对其结构完整性进行了测定，从而鉴定出了MEF2结合元件，更可能激活基因表达。此外，我们还发现另一种温性鱼类medaka的肌球蛋白重链基因的5'上游区域也参与了这种温度依赖性基因表达的调控。低温驯化后，55 kDa胞质蛋白表达量增加。该蛋白是线粒体fof1 - atp酶的一个亚基，当温度从30℃升高到10℃时，其数量增加了2倍。这种随驯化温度的不同表达在转录水平上受到调控。常年定期采集霞光湖各类鱼类，测定快速骨骼肌肌原纤维atp酶活性。11月采鱼时活性最高，6、7月逐渐降低至最低。建立了用电压敏感探针和荧光成像技术测定线粒体膜电压的分析方法。该方法成功地测量了鱼类线粒体膜在适应环境温度后的电压相关势能变化。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