花斑裸鲤Epo和Epor基因克隆及其低氧诱导的mRNA表达

cDNA Cloning and Hypoxia-Induced mRNA Expression of Epo and Epor Genes in Gymncypris eckloni

促红细胞生成素(EPO)是一种糖蛋白激素,在动物低氧适应中发挥着重要作用。本研究采用RT-PCR方法克隆了花斑裸鲤(Gymncypris eckloni)Epo和Epor基因的编码序列,并开展了分子进化和低氧诱导表达研究。结果表明,花斑裸鲤Epo基因编码序列长度为552 bp,编码183个氨基酸;Epor基因编码序列长度为1 590 bp,编码529个氨基酸。氨基酸序列同源性分析显示,花斑裸鲤促红细胞生成素(EPO)和促红细胞生成素受体(EPOR)与鲤科其他鱼类均有较高的同源性,表明在进化过程中具有较强保守性,同时花斑裸鲤Epo和Epor基因均未经历正向选择。在重度低氧[溶解氧为(0.3±0.1)mg/L]和中度低氧[溶解氧为(3.0±0.1)mg/L]胁迫下,花斑裸鲤部分关键组织如红肌、脑组织中Epo m RNA表达量急剧升高,表明促红细胞生成素(EPO)可能在花斑裸鲤运动、神经营养和神经保护方面发挥了重要作用,是对低氧环境适应的一种调节机制。

Erythropoietin （EPO） is a glycoprotein hormone that plays a potential role in hypoxic adaptation in animals. In the present study, the encoding sequences of Epo and Epor genes were cloned in Gymncypris eckloni by RT-PCR method. The coding region of Epo and Epor were 552 bp and 1 590 bp, which encoded 183 and 529 amino acid residues respectively （Fig. 1 and 2）. The high homology of EPO and EPOR protein of G. eckloni with other cyprinid fishes indicated that the two proteins were evolutionary conserved （Table 2）. Molecular evolution analysis suggested that Epo and Epor genes of G. eckloni did not undergo positive selection （Table 3）. Under severe （the dissolved oxygen was 0.3 ± 0.1 mg/L） and moderate hypoxic （the dissolved oxygen was 3.0 ± 0.1 mg/L） conditions, the Epo mRNA levels in key tissues such as brain and red muscle were increased significantly （Fig. 4 and 5）, implying its potential roles in movement, neuroprotection and neurotrophy, which may be a regulatory mechanism of fish to hypoxic adaptation.