草鱼IFI58基因的鉴定及其表达分析

Molecular Cloning,Identification and Expression of IFI58 Gene From Grass Carp(Ctenopharyngodon Idella)

草鱼IFI58全长cDNA为1764 bp,其中ORF为1440 bp,编码1个479 aa的蛋白。草鱼IFI58包含有10个TPR 34肽结构域,并与哺乳类IFIT相对应。其中,TPR7被中间插入序列分为TPR7A和B,TPR4也有5个氨基酸插入,TPR3只有B部分而缺少A部分。鱼类IFI基因与哺乳类的同源性不高,系统进化树也显示它与哺乳类的同源物分别位于两大不同分支上。草鱼IFI58基因在被检测的心、肝、脾、肾、肌、鳃、脑和肠等8个组织中均有本底表达。Poly I:C诱导后,草鱼IFI58表达水平都有明显的上升,其中,在心和脑组织中,诱导后第4 d达到峰值,其余组织均在第3 d达到最高表达水平。总体来说,草鱼IFI58在心、肝、脾和肾组织中的表达量比肌、鳃、脑和肠要稍高些。

The full length of IFI58 cDNA from grass carp（Ctenopharyngodon idella） which contains 1764 bp is cloned.The ORF with the length of 1440 bp encodes a protein of 479 aa.The protein contains ten TPRs（tetratri copeptide repeat）motifs which consist of 34 amino acids and all corresponding to the mammalian members of IFIT gene family.The TPR7 is divided into A and B parts by insert sequence and TPR4 also has four amino acids insertion but the TPR3 has only the B part with the A part is missing.The homology of IFIT genes between fish and mammalian is very lower and phylogenic analysis also shows that the members of mammalian and fish IFIT gene family were located in two different branches.It had constitutive expression in all tissues tested include heart,liver,spleen,kidney,muscle,gill,brain and intestins,and all obviously increased after injected with Poly I：C.The expression of the IFI58 gene in heart and brain reached the peak in the forth day after induction while the other reached the peak in the third day.As a whole,the heart,liver,spleen and kidney showed a higher expression level than muscle,gill,brain and intestines.