许氏平鲉MyoD1s基因的鉴定及其调控成肌细胞分化功能的初步研究

Preliminary Functional Analysis of MyoD1s Genes in Regulating the Myoblast Differentiation in Black Rockfish(Sebastes schlegelii)

在脊椎动物肌肉发育过程中,MyoD1基因可通过多个途径激活肌肉生长相关基因的表达,是成肌细胞增殖和分化的主要调控因子之一。目前关于经济鱼类MyoD1基因的研究主要集中在基因克隆和组织表达情况的分析,而对其功能的研究非常有限。本研究鉴定了许氏平鲉MyoD1基因两个拷贝,分别命名为MyoD1和MyoD1-like。MyoD1-like基因与MyoD1基因ORF序列存在19 bp的碱基差异,且MyoD1-like基因仅含有外显子而无内含子。qRT-PCR表达分析结果显示,MyoD1s基因在肌肉组织中的表达量显著高于其他组织,且MyoD1-like基因的表达显著高于MyoD1。原位杂交结果显示,MyoD1s基因的表达位置是肌纤维的边缘,即成肌细胞增殖、分化的位置。过表达许氏平鲉MyoD1-like基因可诱导小鼠成肌细胞发生分化,融合形成肌管。该结果为研究MyoD1基因在经济鱼类肌肉生长发育过程中的调控作用奠定了基础。

As the key regulator of myoblast proliferation and differentiation,MyoD1 gene could activate the expression of muscle-growth related genes through multiple pathways.At present,studies of MyoD1 gene in economic fish have focused on gene cloning and tissue expression,whereas functional analysis is limited.In this study,two copies of MyoD1 genes,named MyoD1 and MyoD1-like,were distinguished in black rockfish(Sebastes schlegelii).There is a 19 bp-difference in ORF sequences between MyoD1 and MyoD1-like.MyoD1-like gene contains only exons without introns.qRT-PCR analysis demonstrated that MyoD1s genes were mainly expressed in muscle tissues.In situ hybridization analysis illustrated that MyoD1s genes were expressed at the edge of muscle fibers,where the proliferative and differentiated myoblast was located.Overexpression of MyoD1-like in mouse myoblast cell line C2C12 induced cell differentiation and the formation of myotube.This study lays the foundation to advance the functional study of MyoD1 in the muscle growth regulation in economic fish.