草鱼与鲢鱼肥胖基因克隆与序列分析

肥胖基因产物leptin是调节哺乳动物摄食、能量代谢等生命活动的重要细胞因子。 应用RT-PCR和RACE法获得了草鱼(Ctenopharyngodon idellus)和鲢鱼(Hypophthalmichthys molitrix) leptin基因的全长cDNA序列分别为1 096 bp和1 176 bp，编码173和172个氨基酸。氨基酸序列同源性分析表明，草鱼和鲢鱼的leptin序列与其它鲤科鱼类leptin的同源性较高，而与其他鱼类的leptin同源性很低，但所有鱼类的leptin均含有用于形成二硫键的高度保守的半胱氨酸。系统进化树分析显示，草鱼和鲢鱼leptin与其他鱼类leptin聚于一进化分支。应用PCR和Genome Walker方法，进一步获得了草鱼和鲢鱼leptin基因的内含子和5′侧翼区序列。结果表明，获得的草鱼和鲢鱼leptin基因长度分别为2 129 bp和2 192 bp，含有与其他脊椎动物leptin相似的基因结构（含三个外显子和两个内含子）。本研究为深入研究鱼类肥胖基因结构功能关系与鱼类抗肥胖品系定向遗传选育奠定了良好的基础。

Molecular Cloning and Analysis of Leptin Gene in Grass Carp (Ctenopharyngodon idellus) and Silver Carp (Hypophthalmichthys molitrix)

Leptin,the product of the obese gene,is one of the key factors for the regulation of food intake and whole-body energy balance. Both grass carp (Ctenopharyngodon idellus) and silver carp (Hypophthalmichthys molitrix) leptin full-length cDNA were cloned by RT-PCR and RACE methods. The sequences of leptin cDNA in grass carp and silver carp were 1 096 bp,1 176 bp,and the deduced protein had 173,172 amino acids respectively. The amino acid homologues analysis showed high identity in cyprinid fish. Despite lower...