ABSTRACT
The pseudorabies virus (PRV) early protein EP0 is a homologue of the herpes simplex virus 1 (HSV-1) immediate-early protein ICP0, which is a multifunctional protein and important for HSV-1 infection. However, the exact function of EP0 is not clear. In this study, using polymerase chain reaction, a 1,104 base-pair sequence of the EP0 gene was amplified from the PRV Becker strain genome and identification of the EP0 gene was confirmed by further cloning and sequencing. Bioinformatics analysis indicated that the PRV EP0 gene encoded a putative polypeptide with 367 amino acids. The encoded protein, designated as EP0 contained a conserved RING-finger superfamily domain and was found to be closely related with the herpes virus RING-finger superfamily and was highly conserved among the counterparts encoded by RING-finger genes. Multiple nucleic acid sequence and amino-acid sequence alignments suggested that PRV EP0 showed a relatively higher similarity with EP0-like proteins of genus Varicellovirus than with those of other genera of Alphaherpesvirinae. In addition, phylogenetic analysis showed that PRV EP0 had a close evolutionary relationship with members of genus Varicellovirus, especially bovine herpesvirus 1 (BoHV-1) and BoHV-5. Antigen prediction indicated that several potential B-cell epitopes were located in EP0. Also, subcellular localization analysis demonstrated that EP0 was predominantly localized in the nucleus, suggesting that it might function as a nuclear-targeted protein.
Subject(s)
Amino Acid Sequence , Animals , Base Sequence , Cattle , Cloning, Molecular , Computational Biology , DNA, Viral/genetics , Herpesvirus 1, Suid/genetics , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction , Protein Structure, Secondary , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid , Viral Proteins/chemistry , Viral Proteins/geneticsABSTRACT
Suid herpesvirus 1 (SuHV-1) is the causative agent of pseudorabies (PR), a disease of great importance due to the huge losses it causes in the swine industry. The aim of this study was to determine a method for genotyping SuHV-1 based on partial sequences of the gene coding for glycoprotein C (gC) and to elucidate the possible reasons for the variability of this region. A total of 109 gCsequences collected from GenBank were divided into five major groups after reconstruction of a phylogenetic tree by Bayesian inference. The analysis showed that a portion of gC (approximately 671 bp) is under selective pressure at various points that coincide with regions of protein disorder. It was also possible to divide SuHV-1 into five genotypes that evolved under different selective pressures. These genotypes are not specific to countries or continents, perhaps due to multiple introduction events related to the importation of swine.
Subject(s)
Animals , Genetic Variation , Glycoproteins/genetics , Herpesvirus 1, Suid/genetics , Herpesvirus 1, Suid/pathogenicity , Pseudorabies/genetics , Base Sequence/genetics , Varicellovirus/genetics , Varicellovirus/pathogenicity , Genetics, Microbial , Genotype , Methods , VirulenceABSTRACT
Replication-incompetent adenoviruses expressing three major glycoproteins (gB, gC, and gD) of pseudorabies virus (PrV) were constructed and used to examine the ability of these glycoproteins to induce protective immunity against a lethal challenge. Among three constructs, recombinant adenovirus expressing gB (rAd-gB) was found to induce the most potent immunity biased to Th1-type, as determined by the IgG isotype ratio and the profile of the Th1/Th2 cytokine production. Conversely, the gC-expressing adenovirus (rAd-gC) revealed Th2-type immunity and the gD-expressing adenovirus (rAd-gD) induced lower levels of IFN-gamma and IL-4 production than other constructs, except IL-2 production. Mucosal delivery of rAd-gB induced mucosal IgA and serum IgG responses and biased toward Th2-type immune responses. However, these effects were not observed in response to systemic delivery of rAd-gB. In addition, rAd-gB appeared to induce effective protective immunity against a virulent viral infection, regardless of whether it was administered via the muscular or systemic route. These results suggest that administration of replication-incompetent adenoviruses can induce different types of immunity depending on the expressed antigen and that recombinant adenoviruses expressing gB induced the most potent Th1-biased humoral and cellular immunity and provided effective protection against PrV infection.