摘要：

旨在深入了解荷斯坦奶牛脂肪酸结合蛋白4(FABP4)的分子功能,及其在不同组织中的表达规律。以荷斯坦奶牛的乳腺组织为cDNA模板,通过PCR扩增荷斯坦奶牛FABP4基因的编码区序列(Coding sequence,CDS),并进行生物信息学分析;利用qRT-PCR技术检测了FABP4基因在小肠、肝脏、乳腺、心脏、子宫、肾脏及卵巢组织中的mRNA相对表达水平。结果表明,荷斯坦奶牛FABP4基因编码区序列长399 bp,编码133个氨基酸,蛋白质二级结构以β-折叠为主。FABP4蛋白为稳定亲水性蛋白,无跨膜结构和信号肽剪切位点。通过氨基酸同源性分析发现,牛FABP4与绵羊和山羊之间的亲缘关系最近;核质定位表明,FABP4基因可能在细胞质中发挥重要功能。利用STRING对FABP4进行蛋白互作分析发现,与FABP3、PPARG、LIPE等脂质相关蛋白密切相关。qRT-PCR结果显示,FABP4在泌乳中期奶牛的各组织中均有表达,但在奶牛乳腺组织中表达量最高,显著高于其他组织(P<0.05)。本研究为后续深入研究荷斯坦奶牛中FABP4的生物学功能及乳脂调控机制提供了重要的理论依据。

关键词: 荷斯坦奶牛, FABP4, 克隆, 生物信息学, 组织表达谱

Abstract:

The study aims to understand the molecular function of fatty acid binding protein 4(FABP4)in Holstein cows and its expression pattern in different tissues.The coding sequence(CDS)of FABP4 gene was amplified by PCR using mammary tissue of Holstein cows as cDNA template,and bioinformatics analysis was performed.The qRT-PCR was used to detect the relative mRNA expression levels of FABP4 gene in small intestine,liver,mammary gland,heart,uterus,kidney and ovary tissues.The results showed that the sequence of the coding region of FABP4 gene in Holstein cows was 399 bp long,encoding 133 amino acids,and the secondary structure of the protein was mainly β-folded.The amino acid homology analysis revealed that bovine FABP4 was most closely related to sheep and goats;nucleoplasmic localization indicated that FABP4 gene might play an important function in the cytoplasm.Protein interaction analysis of FABP4 using STRING revealed that it was closely related to lipid-related proteins such as FABP3,PPARG,and LIPE.The qRT-PCR showed that FABP4 was expressed in all tissues of mid-lactation cows,but the highest expression was found in the mammary tissue of cows,which was significantly higher than other tissues(P<0.05).This study provides an important theoretical basis for the subsequent further study of the biological function and milk fat regulation mechanism of FABP4 in Holstein cows.

Key words: Holstein cows, FABP4, Cloning, Bioinformatics, Tissue expression profiling