肌肉生长抑制素(MSTN)基因对肌肉生长起负调控作用,在动物育种上具有潜在的应用前景。报道了眼斑拟石首鱼(Sciaenops ocellatus)的MSTN基因的序列结构特征及其组织特异性表达。MSTN基因具有3个外显子和2个内含子,编码376个氨基酸。在内含子Ⅰ和3′-UTR区内,分别发现了(TC)4CC(TC)4CT(TC)4和(AC)7微卫星序列。推断的眼斑拟石首鱼的MSTN氨基酸序列具很强的保守性,与石鼓鱼、金鲷、条纹石鮨、白鲈、金眼石鮨之间的相似性在90%以上。在结构上,眼斑拟石首鱼的MSTN包含N端信号序列(1~22氨基酸残基),TGF-β前肽域(41~256氨基酸残基),RXXR蛋白水解位点(264~267位的RARR)和TGF-β区域(282~376氨基酸残基)。在检测的10种组织中,MSTN只在眼斑拟石首鱼的肌肉、脑和眼组织中表达,其中在肌肉表达最强。
Myostatin is a negative regulator of skeletal muscle growth and has a potential application in aquaculture. The characterization of the myostatin gene and its expression in the red drum fish, Sciaenops ocellatus, were reported. The myostatin gene possessed three exons encoding 376 amino acids. The cDNA was 1 750 bp long with a 108 bp 5′-UTR and a 511 bp 3′--UTR. Two microsatellite sequences, (TC)4 CC(TC)4(CT(TC)4 and (AC)7, existed in intron Ⅰ and 3′-UTR, respectively. The deduced amino acid sequence was highly conserved, and had more than 90% identical to Umbrina cirrosa, Sparusaurata, Motone saxatilis, Morone americana, and Morone chrysops proteins. The myostatin of the red drum had a putative amino terminal signal sequence (residues 1-22), a TGF-β propeptide domain (residues 41 256), a RXXR proteolytic processing site (RARR, residues 264-267, matching the RXXR consensus site), and a TGF-β domain (residues 282-376). There were 13 conserved cysteine residues in the red drum myostatin, nine of which are common to all TGF-β super(amily members. The most conserved region of vertebrate myostatins is the TGF-β domain, which was the mature bioactive domain of the myostatin protein. In the examined ten tissues, the myostatin gene was expressed only in three, the skeletal muscle, brain and eye. The strongest expression was in the skeletal muscle.