团头鲂MSTN基因cDNA结构、表达及过表达对胚胎发育的影响

MOLECULAR STRUCTURE AND EXPRESSION OF MYOSTATIN IN MEGALOBRAMA AMBLYCEPHALA AND ITS OVEREXPRESSION EFFECTS IN EMBRYO

研究通过c DNA末端快速扩增法(RACE)克隆得到团头鲂生长抑制素(MSTN)基因的c DNA全长并分析了MSTN基因在团头鲂胚胎、成鱼组织中表达以及MSTN基因在胚胎中过表达情况。结果表明团头鲂MSTN基因的c DNA全长为2187 bp,ORF(开放阅读框)大小为1128 bp,编码376个氨基酸。组织逆转录PCR(RT-PCR)结果显示,MSTN基因在肌肉、脑和精巢组织中大量表达,肝脏、脾脏和卵巢组织中的少量表达,肠、腮、心、眼和肾组织中的微量表达。胚胎逆转录PCR(RT-PCR)结果显示,在0—44 hpf胚胎发育阶段,MSTN基因表达量较低;而在48—52 hpf胚胎发育阶段,MSTN基因表达量逐渐升高。整胚原位杂交(WISH)结果显示,胚胎发育的16 hpf时期MSTN基因主要在脊索中表达,胚胎发育的28 hpf和55 hpf时期MSTN基因在脑中表达。MSTN基因过表达结果显示,胚胎在体节发生期出现前-后轴拉长,背-腹轴变短;脊索发生扭曲,强烈抑制体节发育而导致不分化等现象。研究为后续团头鲂MSTN基因的功能研究及团头鲂分子育种提供相关参考依据。

The current study cloned a 2187 bp full-length cDNA of myostatin from blunt snout bream （Megalobramaamblycephala） by rapid amplification of cDNA ends （RACE）. Its open reading frame is 1128 bp encoding 376 aminoacids. RT-PCR analysis demonstrated that MSTN are extensively expressed in tissues of blunt snout bream with highlevel in the muscle, brain and testis is the highest, modest level in the liver, spleen, and ovary, and low level in intestine,gills, heart, eye, and kidney. During embryos development, mRNA level of MSTN is low from 0 to 44 hpf, whereas itsexpression increases gradually from 48 hpf to 52 hpf. The whole mount in situ hybridization demonstrated that MSTNmRNA was transcribed at different tissues of blunt snout bream’s embryos. MSTN mRNA were detected at the Noto-chord at 16 hpf. In 28 hpf and 55 hpf embryos, the MSNT mRNA level was very high in brain. Overexpression MSTNmRNA in embryos caused elongated anterior-posterior axis, shorter dorsalventral axis, slightly distorted notochord,and strongly inhibited somites. This study provides knowledge for subsequent blunt snout bream MSTN gene functionresearch and molecular breeding of blunt snout bream.