iTRAQ-based Proteomics Reveals Candidate Proteins of Fat Deposition in Chinese Indigenous Sheep with Morphologically Different Tails

Chinese indigenous sheep can be classified into two types according to their tail morphology: fat-rumped and thin-tailed sheep, of which the typical breeds are Altay sheep and Tibetan sheep, respectively. To identify the differentially expressed proteins (DEPs) underlying the phenotypic differences between tail types, we used iTRAQ combined with multi-dimensional liquid chromatography tandem mass spectrometry (LC-MS/MS) technology to detect candidate proteins. We then subjected these to a database search, and identified the DEPs. Finally, bioinformatics technology was used to carry out GO functional and KEGG pathway analyses. A total of 3248 proteins were identified, of which 44 were up-regulated and 40 were down-regulated DEPs. Analyzing their GO function terms and KEGG pathways revealed that the functions of these DEPs are mainly binding, catalytic activity, structural molecule activity, molecular function regulator, and transporter activity. Among the genes encoding the DEPs, APOA2, GALK1, ADIPOQ, and NDUFS4 are associated with fat formation and metabolism.

中国本土绵羊可根据尾型分为两类：脂臀型绵羊与瘦尾型绵羊，其典型品种分别为阿勒泰羊与藏羊。为鉴定尾型表型差异背后的差异表达蛋白（differentially expressed proteins，DEPs），本研究采用iTRAQ结合多维液相色谱串联质谱（LC-MS/MS）技术检测候选蛋白，随后对其进行数据库检索以鉴定DEPs，最终利用生物信息学技术开展GO功能注释与KEGG通路富集分析。本研究共鉴定得到3248个蛋白，其中上调DEPs 44个、下调DEPs 40个。对这些DEPs的GO功能条目与KEGG通路分析结果显示，其分子功能主要涵盖结合活性、催化活性、结构分子活性、分子功能调节因子活性以及转运蛋白活性。在编码DEPs的基因中，APOA2、GALK1、ADIPOQ及NDUFS4与脂肪形成及代谢相关。