The cDNA sequence encoding fibroblast growth factor 8 ( FGF8 ) was cloned from the brain of Ctenopharyngodon idellus by RACE methods. This cDNA fragment was 887 bp in length, containing 100 bp 5'-UTR, 157 bp 3'-UTR, and an open reading frame (ORF) of 633 bp. The ORF encoded a precursor of 210 amino acids, including a signal peptide of 22 amino acids and a mature protein of 188 amino acid residues. Phylogenetic analysis of the known FGF8 sequences revealed that C. idellus clustered closer to Danio rerio and Astyanax mexicanus, but farther from amphibians, birds and mammals. This result suggested that C. idellus had a closer genetic relationship with the two cyprinid fishes in comparison with other vertebrates, which corresponded well to those expected from morpho-taxonomy. The molecular structure of C. idellus FGF8 was also elucidated using bioinformatics methods.%以草鱼(Ctenopharyngodon idellus)为实验对象,利用RACE技术克隆了草鱼成纤维细胞成长因子8(Fibroblast Growth Factor 8,FGF8) cDNA序列.实验结果显示,草鱼FGF8 cDNA序列长度为887 bp,其中5′-非翻译区长100 bp,3′-非翻译区长157 bp,开放阅读框(ORF)633 bp,编码210个氨基酸的前体蛋白,包含22个氨基酸的信号肽和188个氨基酸的成熟肽.利用已知的FGF8序列绘制系统发育树,发现草鱼与两种鲤科鱼(班马鱼、墨西哥脂鲤)聚为一簇,显示亲缘关系很近,而与其它脊椎动物如两栖类、鸟类、哺乳类的亲缘关系则相对较远,这与形态分类学的结果一致.此外,还通过生物信息学分析,揭示了草鱼FGF8的分子结构特征.
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