勒氏笛鲷(Lutjanus russellii)肌肉生长抑制素基因的克隆与分析

Cloning and Analysis of the Myostatin (MSTN) Gene in Russell’s Snapper, Lutjanus russellii

以勒氏笛鲷(Lutjanus russellii)基因组DNA为模板,采用同源克隆的方法,获得2 887 bp的肌肉生长抑制素(myostatin,MSTN)基因组序列,该MSTN序列具有3个外显子和2个内含子,包括101 bp的5′-UTR、385bp的外显子1、354 bp的内含子1、370 bp的外显子2、761 bp的内含子2、381 bp的外显子3和1 932 bp的3′-UTR。整个开放阅读框编码了378个氨基酸,前面的22个氨基酸为信号肽,具有9个保守的半胱氨基酸及一个RVRR的蛋白酶解加工位点。氨基酸序列分析发现,该基因编码的蛋白质与其他鱼类的I型同源性较高,与其他鱼类的2型MSTN同源性较低,且与鲈形目的同源性最高,与鲤形目的同源性较低,与人、鼠和鸡的同源性最低。采用邻接法(Neighbor-Joining)构建的MSTN的系统发育树表明,勒氏笛鲷MSTN与鲈形目鱼类的狼鲈属亲缘关系较近,且与鱼类的MSTN-1聚为1支。这表明该基因属于Ⅰ型MSTN基因。

Myostatin（MSTN） gene was isolated from Russell’s snapper,Lutjanus russellii by homology cloning method with the genome DNA.The Russell’s snapper MSTN was 2887 bp in length,including three exons and two introns,along with 101 bp 5′-UTR（untranslated region）,385 bp exon 1,354 bp intron 1,370 bp exon 2,761 bp intron 2,381 bp exon 3 and 1 932 bp 3′-UTR.The Russell’s snapper MSTN gene encodes a 378 amino acid protein,including nine conserved cysteine residues,a RVRR proteolytic cleavage domain,and a putative signal peptide of 22 amino acids.Amino acid sequence analyses show the Russell’s snapper MSTN has closer affinity with type 1 MSTN than type 2 MSTN of several telests.And it has the highest identity with Perciformes,higher identity with Cypriniformes,and the least identity with that of mouse,human and chicken MSTN.Neighbor-joining method and the results also show Russell＇s snapper has the closest homology with morone.And it clusters with type 1 MSTN of fish.It suggests that the Russell＇s snapper MSTN we isolated may belong to type Ⅰ MSTN.