Correlation between the expressions of CSN1S2 and CSN3 gene and milk production in mammary gland of Xinong Saanen Dairy Goat | CSN1S2和CSN3基因表达量与西农萨能奶山羊产奶性状的关系

Chinese. 研究酪蛋白中αs2酪蛋白(CSN1S2)基因和K酪蛋白(CSN3)基因在西农萨能奶山羊乳腺组织中的表达量及其与产奶性状的关系。根据山羊CSN1S2和CSN3的mRNA序列（CSN1S2：AJ289716，CSN3：EF564258）设计实时定量特异性引物，采用实时荧光定量PCR法，对年均产奶量不同的3组西农萨能奶山羊进行mRNA转录水平上的相对定量分析，并测定乳脂和乳蛋白的含量，同时对扩增出的mRNA片段进行克隆测序。CSN1S2基因在第1组15只西农萨能奶山羊（年均产奶量为 (1 100.00±15.00) kg）乳腺组织中的相对表达量是第2组15只奶山羊（年均产奶量为(600.00±12.00) kg）的2.47倍，二者差异极显著(P0.01)；CSN3基因在第1组西农萨能奶山羊乳腺组织中的表达量是第2组的3.10倍，二者差异极显著(P0.01)；测序后进行序列比对发现，目的mRNA片段与山羊CSN1S2和CSN3基因的同源性均为100%；CSN1S2基因在西农萨能奶山羊乳腺组织中的表达量与乳汁中蛋白质含量相关性不显著，与脂肪含量呈显著负相关；CSN3基因的表达量与乳汁中蛋白质含量呈显著正相关，与脂肪含量相关性不显著。CSN1S2基因和CSN3基因在西农萨能奶山羊乳腺中的表达量对乳蛋白和产奶量有显著影响(P0.05)，可作为西农萨能奶山羊产奶性状选育的候选基因。

English. The relationship between the milk production traits and the expression levels of CSN1S2 gene and CSN3 gene in the breast gland of Xinong Saanen Dairy Goat was detected in this study. Two pairs of Real-time quantitative specific primers were designed based on the mRNA sequence of CSN1S2 (AJ289716) gene and CSN3 (EF564258) gene, and SYBR Green reaction system of real-time fluorescent quantitative PCR was used to detect the relative quantitative analysis on mRNA transcription level of CSN1S2 gene and CSN3 gene in Xinong Saanen Dairy Goat. The amplified DNA segments were cloned and sequenced. Meanwhile the milk fat and lactoprotein was detected using fast milk composition analysis instrument. The results showed that the relative average expression of CSN1S2 gene in the first group including 15 goats whose milk production of one lactation period was (1 100.00±15.00) kg was 2.47 folds higher than that of the second group, (600.00±12.00) kg, while the relative average expression of CSN3 gene in the first group was 3.10 folds higher than that of the second group. When blasted the sequenced DNA, it showed that the amplified DNA segments shared 100% homology with the target segments. The expression of CSN1S2 gene in goat mammary gland was positively correlated (P0.05) with protein content, and negatively correlated (P0.05) with fat content in goat milk. The expression of CSN3 gene was positively correlated with protein content (P0.05). The expression of CSN1S2 gene and CSN3 gene in Xinong Saanen Dairy Goat mammary gland has a significant influence (P0.05) on milk production, milk protein and milk fat, and can be used as breeding dairy goat milk production traits of the candidate genes.