松江鲈肌肉生长抑制素基因克隆和序列特征分析

Identification and Characterization of Myostatin Gene in Rough-skinned Sculp,Trachidermus fasciatus

肌肉生长抑制素(myostatin)属于转化生长因子β(TGF-β)超家族中的一个成员,是控制骨骼肌生长发育的重要细胞因子。该研究以松江鲈肌肉总RNA为模板,采用RT-PCR、5'-RACE和3'-RACE的方法,获得了松江鲈MSTN基因的3个片段,测序后拼接得到2568bp全长cDNA序列,其包含了1131个核苷酸的开放性阅读框,翻译编码376个氨基酸。松江鲈MSTN具有MSTN的共同特征,有蛋白酶水解位点RARR和10个保守的半胱氨酸残基;核苷酸和氨基酸同源性分析发现,松江鲈MSTN基因序列与石首鱼、条纹狼鲈、美洲白鲈、金眼石鮨等同源性较高;与哺乳动物和鸟类同源性较低。系统发育分析表明,松江鲈MSTN与石首鱼亲缘关系最近。RT-PCR分析表明,该基因在肌肉表达量最高;在肠中也有较高表达;在脑和肝脏中也能检测到表达。此结果表明,松江鲈MSTN基因除对肌肉生长发育有调控作用以外,可能还有其他功能。

Myostatin is a member of the TGF-β superfamily and acts as a negative regulator of skeletal muscle growth.The characterization of the myostatin gene and its expression in Trachidermus fasciatus was reported in the current study.A full-length of 2 568 bp myostatin cDNA sequence in T.fasciats was cloned by 5＇ and 3＇ RACE,which included a 1 131 bp complete ORF encoding a 376 amino acid peptide,a 106 bp long 5＇-UTR and a 1331 bp long 3＇UTR.As other MSTN,the putative peptide contains a 22 amino acids long signal peptide,a conserved RARR proteolytic processing site,and 10 conserved cysteine residues in the C terminal of the protein.The Trachidermus fasciatus MSTN has high homology with Umbrina cirrosa,Morone saxatilis,Morone americana,Morone chrysops myostatin while has low homology with mammalian and birds myostatin.The phylogenetic analysis showed that the T.fasciatus myostatin had the closest relationship with U.cirrosa.In the four examined tissues,the myostatin gene was highly expressed in muscle and intestine and weakly expressed in brain and liver.These results suggested that the fish myostatin gene might not only play roles in muscle development but also contribute to other biological functions.