[目的]研究黄淮肉羊胰岛素样生长因子1(insulin like growth factor 1，IGF1)基因序列特征、组织表达规律，并对背最长肌中IGF1基因的表达量与产肉性状进行相关性分析。[方法]选取3、9、18月龄的黄淮肉羊公羊各3只，屠宰后迅速采集半腱肌、股四头肌、臂三头肌、背最长肌、皮下脂肪、瘤胃、肾脏、脾脏、肝脏、睾丸和小肠组织样品并测定其产肉性能。对黄淮肉羊IGF1基因进行克隆测序，并进行生物信息学分析，利用实时荧光定量PCR技术检测其在黄淮肉羊同一年龄(9月龄)各组织以及不同年龄阶段(3、9、18月龄)背最长肌中的mRNA水平，利用皮尔逊相关系数分析IGF1基因的表达量与产肉性状的相关性。[结果]克隆获得黄淮肉羊IGF1基因CDS序列465 bp，编码154个氨基酸，与山羊的亲缘关系最近。黄淮肉羊IGF1蛋白为亲水性不稳定蛋白，无跨膜结构，存在信号肽，有29个潜在的磷酸化位点。黄淮肉羊IGF1蛋白二级结构主要含有无规则卷曲(54。55％)和α-螺旋(29。87％)，三级结构预测结果与二级结构一致。IGF1蛋白与IGF1R、IGFBP3、IGF2等存在蛋白互作关系。实时荧光定量PCR结果显示，IGF1基因在黄淮肉羊各组织中均有表达，在肝脏组织中表达量最高，在臂三头肌中表达量最低。IGF1基因在3月龄黄淮肉羊背最长肌中表达量最高，显著高于9和18月龄(P＜0。05)，而9月龄的表达量又显著低于18月龄(P＜0。05)。相关性分析结果表明，IGF1基因表达量与生长发育和肉品质指标无显著相关(P＞0。05);体高、体长、胸围、管围、体重和胴体重之间呈显著或极显著正相关(P＜0。05;P＜0。01);屠宰率、肉色、大理石纹、眼肌面积之间呈显著或极显著正相关(P＜0。05;P＜0。01)。[结论]本研究成功克隆了黄淮肉羊IGF1基因CDS区序列，IGF1蛋白属于亲水不稳定碱性蛋白，主要在肝脏中表达，在背最长肌中的表达趋势表现为随着月龄增长先降后升，与生长发育和肉品质指标无显著相关性。这些结果为进一步探究黄淮肉羊IGF1基因在肌肉发育与肉品质调控中的作用提供参考。
Sequence Characteristics,Tissue Expression of IGF1 Gene and Correlation with Production Trait in Huanghuai Sheep
[Objective]This study was aimed to research the sequence characteristics and tissue expression patterns of insulin like growth factor 1(IGF1)gene in Huanghuai sheep,and conduct correlation analysis between the expression of IGF1 gene in longissimus dorsi muscle and meat production traits.[Method]The 9 male Huanghuai sheep at the ages of 3,9,and 18 months each were selected.The meat production performance were determined and semitendinosus,quadriceps femoris,triceps brachii,longissimus dorsi muscle,subcutaneous fat,rumen,kidney,spleen,liver,testis and small intestine tissue samples were collected after slaughter.the IGF1 gene of Huanghuai sheep was cloned and sequenced,and analyzed by bioinformatics analysis.The mRNA levels of IGF1 gene in various tissues at 9-month-old and in the longissimus dorsi muscle at different age stages were detected by Real-time quantitative PCR,and the correlation between IGF1 expression and meat production traits were analyzed through Pearson correlation coefficient.[Result]The CDS region size of IGF1 gene in Huanghuai sheep was 465 bp,encoding 154 amino acids,indicating the closest genetic relationship with Capra hircus.IGF1 protein of Huanghuai sheep was a hydrophilic and unstable protein with no transmembrane structure.It contained signal peptides and had 29 potential phosphorylation sites.The secondary structure of IGF1 protein in Huanghuai sheep mainly contained random coil(54.55％)and alpha helix(29.87％),and the predicted results of the tertiary structure were consistent with the secondary structure.There were interactions between IGF1 and IGF1R,IGFBP3,IGF2 and other proteins.The results of Real-time quantitative PCR showed that IGF1 gene was widely expressed in the tissues of Huanghuai sheep,with the highest expression in liver and the lowest expression in triceps brachii.The expression level of IGF1 gene was highest in the longissimus dorsi muscle of 3-month-old Huanghuai sheep,significantly higher than that of 9-month-old and 18-month-old sheep(P＜0.05),while the expression of 9-month-old sheep was significantly lower than that of 18-month-old sheep(P＜0.05).The correlation analysis results showed that the expression of IGF1 gene was not significantly correlated with growth traits and meat quality indicators(P＞0.05).There was a significant or extremely significant positive correlation between body height,body length,chest girth,cannon circumference,body weight,and carcass weight(P＜0.05 or P＜0.01).There was also a significant or extremely significant positive correlation between dressing percentage,meat color,marble texture,and loin muscle area(P＜0.05 or P＜0.01).[Conclusion]The CDS sequence of IGF1 gene in Huanghuai sheep was successfully cloned.The IGF1 protein was the hydrophilic and unstable alkaline protein,mainly expressed in the liver,and the general trend in the longissimus dorsi muscle muscle were first decreasing and then rising with age increasing,and was not significantly correlated with growth and development and meat quality indicators.These results provided a reference for further exploring the role of IGF1 gene in muscle development and meat quality regulation in Huanghuai sheep.
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