College of Life Sciences, Southwest Forestry University, Kunming, Yunnan, 650224, China; Key Laboratory of Animal Genetics and Breeding of Ministry of Agriculture, National Engineering Laboratory of Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.
Key Laboratory of Animal Genetics and Breeding of Ministry of Agriculture, National Engineering Laboratory of Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.
Biochem Biophys Res Commun. 2019 Mar 19;510(4):606-613. doi: 10.1016/j.bbrc.2019.01.016. Epub 2019 Feb 8.
In a previous genome-wide association study on milk production traits in Chinese Holstein population, we revealed VPS28 gene was highly expressed in mammary gland tissue and a -58C > T mutation in 5'-UTR of it was significantly associated with milk fat content traits. In this study, we explored the effect of this -58C > T mutation on VPS28, and found it could significantly decrease promoter activity of VPS28 by reducing transcription factor binding sites. To identify the potential functional SNP involved, we performed RNAi experiment in BMECs, the results showed that VPS28 knockdown could increase the expression of ADFP and CD36, lead accumulation of ubiquitinated proteins, long chain fatty acids and triglyceride, and decrease the proteasome activity. Therefore, our study demonstrates that the -58C > T mutation could facilitate milk fat synthesis in two ways. The one is involved in ESCRTs signaling, it could directly lead an accumulation of ubqiuitinated membrane proteins to promote the long chain fatty acids uptake to incorporation into TG. The other is involved in ubiquitination-proteasome system, it could indirectly lead a dysfunction of proteasome to accumulate the ubqiuitinated proteins to promote TG synthesis. In conclusion, our study demonstrates that VPS28 could be a strong candidate gene for milk fat content traits, and in particular, the -58C > T mutation in 5'-UTR of VPS28 could be a functional mutation for its effects on milk fat content.
在之前的中国荷斯坦牛群体产奶性状全基因组关联研究中，我们揭示了 VPS28 基因在乳腺组织中高度表达，其 5'-UTR 中的-58C>T 突变与乳脂含量性状显著相关。在这项研究中，我们探讨了该-58C>T 突变对 VPS28 的影响，发现它可以通过减少转录因子结合位点，显著降低 VPS28 的启动子活性。为了鉴定潜在的功能 SNP，我们在 BMECs 中进行了 RNAi 实验，结果表明 VPS28 敲低可以增加 ADFP 和 CD36 的表达，导致泛素化蛋白、长链脂肪酸和甘油三酯的积累，并降低蛋白酶体活性。因此，我们的研究表明，-58C>T 突变可以通过两种方式促进乳脂合成。一种是涉及 ESCRTs 信号通路，它可以直接导致泛素化膜蛋白的积累，从而促进长链脂肪酸的摄取并将其纳入 TG。另一种是涉及泛素蛋白酶体系统，它可以间接导致蛋白酶体功能障碍，积累泛素化蛋白，从而促进 TG 合成。总之，我们的研究表明 VPS28 可能是乳脂含量性状的一个强候选基因，特别是 VPS28 5'-UTR 中的-58C>T 突变可能是其对乳脂含量影响的一个功能突变。
