Abstract: This study investigated the effect of insulin⁃like growth factor 2 mRNA⁃binding protein 3（IGF2BP3） on the growth and development of porcine skeletal muscle and analyzed its biological function and expression regulation mechanism so as to provide a theoretical basis and candidate genes for genetic improvement in pigs.Porcine skeletal muscle satellite cells were utilized as the experimental material.RT⁃qPCR and Western blot were employed to measure the expression of cell proliferation marker genes PCNA、CDK4、Cyclin A2 and MKI67，and EdU and CCK⁃8 kits were used to detect cell proliferation viability and rate.The dual⁃luciferase assay of SP1 binding site mutations in the promoter region of the IGF2BP3gene and the ChIP assay were employed to investigate the expression regulatory mechanism of the IGF2BP3 gene by the transcription factor SP1.The results showed that knocking down IGF2BP3 in porcine skeletal muscle satellite cells significantly upregulated the expression of cell proliferation marker genes，increased the proportion of EdU positive cells，and significantly increased the cell proliferation rate at 48 and 72 hours.The dual⁃luciferase activity was significantly reduced by mutations in the SP1 binding region，whereas the activity was significantly increased by SP1 overexpression. SP1 could bind to the promoter region of the IGF2BP3 gene.Interference with SP1 decreased IGF2BP3 expression，whereas overexpression of SP1 upregulated IGF2BP3 expression.Overexpression of SP1 partially eliminated the phenotype that knockdown of IGF2BP3 promoted proliferation of porcine skeletal muscle satellite cells. In conclusion，the transcription factor SP1 and the IGF2BP3 gene interact to regulate the proliferation of porcine skeletal muscle satellite cells.

Key words: Pig, Skeletal muscle, IGF2BP3, SP1, Porcine skeletal muscle satellite cell, Proliferation

摘要： 为了探究胰岛素样生长因子2 mRNA结合蛋白3（IGF2BP3）对猪骨骼肌生长发育的影响，并解析其生物学功能和表达调控机制，为猪的遗传改良提供理论依据和候选基因，以猪骨骼肌卫星细胞为试验材料，通过RT-qPCR和蛋白质印迹检测细胞增殖标志基因PCNA、CDK4、Cyclin A2 和MKI67的表达，采用EdU和CCK-8检测细胞增殖活力和速率，通过突变IGF2BP3基因启动子区SP1结合位点的双荧光素酶试验和ChIP试验探索转录因子SP1对IGF2BP3基因的表达调控机制。结果表明，在猪骨骼肌卫星细胞中敲低IGF2BP3后，细胞增殖标志基因的表达均明显上调，EdU阳性细胞比例增加，细胞增殖速率在48、72 h均明显提高。SP1结合位点的突变使双荧光素酶活性明显降低，而过表达SP1使双荧光素酶活性明显增强。SP1可与IGF2BP3基因启动子区结合。干扰SP1后IGF2BP3表达降低，而过表达SP1后IGF2BP3表达增加。过表达SP1能部分消除敲低IGF2BP3促进猪骨骼肌卫星细胞增殖的表型。综上，转录因子SP1与IGF2BP3基因相互作用，共同调控猪骨骼肌卫星细胞增殖。

关键词: 猪, 骨骼肌, IGF2BP3, SP1, 猪骨骼肌卫星细胞, 增殖