College of Life Science and Technology, Jinan University, Shipai, Guangzhou 510632, People's Republic of China.
J Biochem Mol Toxicol. 2010 Sep-Oct;24(5):293-302. doi: 10.1002/jbt.20338.
Heat shock protein 70 (HSP70) protect cell from oxidative stress by preventing the irreversible loss of vital proteins and facilitating their subsequent regeneration. Silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idellus), and Nile tilapia (Oreochromis nilotica) are three warm freshwater fishes with differential tolerance to microcystin-LR (MC-LR). Full-length cDNAs encoding the HSP70 were cloned from the livers of the three fishes. The HSP70 cDNAs of silver carp, grass carp, and Nile tilapia were 2356, 2348, and 2242 bp in length and contained an open-reading frame of 1950 bp (encoding a polypeptide of 649 amino acids), 1950 bp (649 amino acids), and 1917 bp (638 amino acids), respectively. Like mammalian HSP70, the HSP70 of the three fish was also composed of an ATPase domain from residues 1 to 383 (44 kDa), substrate peptide binding domain from residues 384 to 544 (18 kDa), and a C-terminus domain from residues 545 to 649 (10 kDa). The relatively high conservation of HSP70 sequences among different vertebrates is consistent with their important role in fundamental cellular processes. Using beta-actin as an external control, RT-PCR within the exponential phase was conducted to determine the constitutive and inducible expression level of HSP70 gene among the three fishes (6-12 g) intraperitoneally injected with MC-LR (50 μg kg(-1) body weight). Both constitutive and inducible liver mRNA levels of the fish HSP70 genes showed positive relationships with their tolerance to MC-LR: highest in Nile tilapia, followed by silver carp, and lowest in grass carp. The differential expression pattern of liver HSP70 genes in the three fish indicated a potential role of HSP70 in the detoxification process of MC-LR.
热休克蛋白 70（HSP70）通过防止重要蛋白质的不可逆损失并促进其随后的再生，从而保护细胞免受氧化应激。银鲤鱼（Hypophthalmichthys molitrix）、草鱼（Ctenopharyngodon idellus）和尼罗罗非鱼（Oreochromis nilotica）是三种对微囊藻毒素-LR（MC-LR）具有不同耐受能力的温水淡水鱼。从这三种鱼的肝脏中克隆出全长 cDNA 编码 HSP70。银鲤鱼、草鱼和尼罗罗非鱼的 HSP70 cDNA 分别长 2356、2348 和 2242bp，包含一个 1950bp 的开放阅读框（编码 649 个氨基酸的多肽）、1950bp（649 个氨基酸）和 1917bp（638 个氨基酸）。与哺乳动物 HSP70 一样，这三种鱼的 HSP70 也由一个从残基 1 到 383（44kDa）的 ATP 酶结构域、一个从残基 384 到 544（18kDa）的底物肽结合结构域和一个从残基 545 到 649（10kDa）的 C 末端结构域组成。HSP70 序列在不同脊椎动物之间的相对高度保守性与其在基本细胞过程中的重要作用一致。使用β-肌动蛋白作为外部对照，在 MC-LR（50μgkg（-1）体重）腹腔注射的 6-12g 三种鱼中进行指数期内的 RT-PCR，以确定 HSP70 基因的组成型和诱导表达水平。三种鱼的 HSP70 基因的组成型和诱导型肝 mRNA 水平均与它们对 MC-LR 的耐受性呈正相关：尼罗罗非鱼最高，其次是银鲤鱼，草鱼最低。三种鱼肝 HSP70 基因的差异表达模式表明 HSP70 在 MC-LR 的解毒过程中可能具有作用。
