Study On Regulation Of Swine Fever Virus Proteins In Its 3’UTR

The Classical swine fever is caused by the Classical swine fever virus. This disease brings serious economic loss on pigs breeding with its highly pathogenic and highly contagious, and it is regarded by as A kind of disease by the world organization for animal health(OIE).Swine fever virus is a kind of single strand RNA virus in chain. Its genome includes an open reading frame(ORF), a 3’untranslated region and(3’UTR) and a 5’untranslated region(5’UTR).The open reading frame of Classical swine fever virus encodes a protein polyprotein which consists of 3,898 amino acids, and the polyprotein can form into 12 mature protein formation including C, Erns, E1 and E2, Npro, P7, NS2, NS3, NS4 A, NS4 B, NS5 A and NS5 B, with the help of the virus itself protease and host cell signal peptide enzyme. The replication process of the Classical swine fever virus genome involved in a variety of non-structural protein of themselves, and there are researches showed that NS3, NS4 A, NS4 B, NS5 A, NS5 B are essential for its replication. The secondary structure of Classical swine fever virus 3 ’UTR includes four or five stem ring structure, which plays an important role of RNA viral replication.For exploring the regulation of the Classical swine fever virus on its 3’UTR, we transfected PK 15 cells with the eukaryotic expression vector of the Classical swine fever virus each protein and its 3’UTR, and then detected whether the protein regulated its 3’UTR by using dual luciferase report gene detection system. The results showed that the Classical swine fever virus, C, NS4 A,NS5A and NS5 B, had significant adjustment on its 3’UTR.The protein NS5 B and the protein C can inhibit the 3’UTR region’s function and promote the translation of virus, while the protein NS4 A and NS5 A can promote the 3’ UTR’ region’s function and inhibit the translation effect of the virus.In order to study the function of the Classical swine fever virus protein C on its 3’UTR further, we explored the specific site that the C protein worked on its 3’UTR firstly. By building 3’UTR expression vector of different stem loop(SL), and transfection with the C protein eukaryotic expression vector, we found that the regulation site was mainly located in 3 ’UTR 1-139 nt(SL-1 and SL-2) district. At the same time, we studied the amino acid sequence of the Classical swine fever virus C protein’s regulation on its 3’UTR.After using bioinformatics analysis of the, we mutated the conservative amino acid area of the protein C, and the dual luciferase report gene detection system showed that the Classical swine fever virus protein C 59-69 amino acids played a role in regulating its 3’UTR, but not a major role.In this study, we confirmed that the Classical swine fever virus C protein had a function of regulation on its 3’UTR by using the dual luciferase reporter gene detection system. The protein C can inhibit the 3’UTR region’s function and promote the translation of virus, and the regulation site was mainly located in 3 ’UTR 1-139 nt(SL-1 and SL-2)district. The protein C 59-69 amino acids played a role in regulating its 3’UTR.