佛罗里达红罗非鱼黑色素浓集激素1基因的克隆与表达分析

Cloning and expression of melanin-concentrating hormone 1 gene in Florida red tilapia (Oreochromis sp.)

  • 摘要: 采用同源克隆技术获得了佛罗里达红罗非鱼(Oreochromis sp.)前原黑色素浓集激素1 (prepro-melanin concentrating hormone 1,pmch1)基因cDNA全长序列,将其命名为flpmch1;并通过实时荧光定量PCR (qRT-PCR)分析天生黑斑佛罗里达红罗非鱼组织表达谱和低温胁迫后其各组织表达差异。结果表明,flpmch1 cDNA序列全长629 bp,开放阅读框411 bp,编码136个氨基酸,存在12个潜在磷酸化位点和1个长度为199 bp的CpG岛。Flpmch1与24个物种Pmch1氨基酸序列比对结果表明,Flpmch1与尼罗罗非鱼(O.niloticus)、奥利亚罗非鱼(O.aureus)、莫桑比克罗非鱼(O.mossambicus)、布氏新亮丽鲷(Neolamprologus brichardi)的Pmch1相似性最高。系统进化树分析显示硬骨鱼纲Pmch聚成一个大支,Flpmch1与尼罗罗非鱼Pmch1进化地位最接近。组织表达谱分析显示,flpmch1 mRNA在多个组织中均有表达,其中在脑中表达量最高,且粉白色皮肤中的表达量显著高于黑色皮肤(P<0.01)。低温胁迫后flpmch1 mRNA各组织表达量较对照组均呈下调表达。推断flpmch1可能参与了佛罗里达红罗非鱼天生黑斑的形成和过冬黑化过程。

     

    Abstract: We cloned the cDNA sequence of prepro-melanin-concentrating hormone 1 (pmch1) gene in Florida red tilapia (Oreochromis sp.), referred as flpmch1, to analyze the variation in tissue expression for Florida red tilapia with genetic black spots and those after cold stress by real-time quantitative PCR (qRT-PCR). The bioinformatics analysis reveals that the full length of flpmch1 gene was 629 bp, including an open reading frame of 411 bp encoding putative protein of 136 amino acids. It is predicted that the flpmch1 contained 12 potential phosphorylated sites and a CpG island with length of 199 bp. Compared with Pmch1 amino acid structures of 24 species, Flpmch1 was structurally similar with Pmch1 of O.niloticus, O.aureus, O.mossambicus and Neolamprologus brichardi. The phylogenetic tree analysis shows that Flpmch1 and other teleost formed a Clade, and Flpmch1 had the highest identity to O.niloticus Pmch1. In terms of tissue distribution in Florida red tilapia with genetic black spots, flpmch1 mRNA was widely expressed in various tissues with the highest expression level in brain, and the expression level in pinky white skin was significantly higher than that in black skin. The flpmch1 mRNA expression in tissues decreased after cold stress. The results indicate that flpmch1 is involved in the formation of genetic black spots and skin melanin pigmentation for Florida red tilapia after cold stress.

     

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