Pseudorabies virus pUL16 assists the nuclear import of VP26 through protein-protein interaction.

Pseudorabies virus (PRV) is related to alphaherpesvirus and varicellovirus. pUL16 is a conserved protein in all herpesviruses, and studies have shown that UL16 can interact with the viral proteins pUL11, pUL49, pUL21, gD, and gE. In this study, we found that pUL16 interacted with the viral capsid protein VP26, which could not translocate into the nucleus itself but did appear in the nucleus. We further determined whether pUL16 assists the translocation of VP26 into the nucleus. We found that pUL16 interacted with VP26 with or without viral proteins, and since VP26 itself did not contain a nuclear location signal, we concluded that pUL16 assisted the translocation of VP26 into the nucleus. Deletion of UL16 and UL35 significantly reduced the 50 % tissue culture infective dose, virulence, attachment, and internalization of PRV in cells. These results show that the interaction between pUL16 and VP26 influences the growth and virulence of pseudorabies virus. Our research is the first study to show that pUL16 interacts with VP26, which may explain the targeting site of UL16 and viral capsids. It is also the first to show that UL16 assists the transport of other viral proteins to organelles. Previous researches on pUL16 usually emphasized its interaction with pUL11, pUL21, and gE, and sometimes commented on pUL49 and gD. Our research focuses on the novel interaction between pUL16 and VP26, thereby enriching the studies on herpesviruses and possibly providing different directions for researchers.

Characterization of Nucleocytoplasmic Shuttling of Pseudorabies Virus Protein UL46.

Pseudorabies virus (PRV) is the etiological agent of Aujeszky's disease, which has caused severe economic loss in China since its re-emergence in 2011. UL46, a late gene of herpesvirus, codes for the abundant but non-essential viral phosphoproteins 11 and 12 (VP11/12). In this study, VP11/12 was found to localize inside both the nucleus and cytoplasm. The nuclear localization signal (NLS) of VP11/12 was identified as 3RRARGTRRASWKDASR18. Further research identified α5 and α7 to be the receptors for NLS and the chromosome region maintenance 1 (CRM1) to be the receptor for the nuclear export signal. Moreover, we found that PRV VP11/12 interacts with EP0 and the stimulator of interferon genes protein (STING), whereas the NLS of VP11/12 is the important part for VP11/12 to interact with UL48. To our knowledge, this is the first study to provide reliable evidence verifying the nuclear localization of VP11/12 and its role as an additional shuttling tegument protein for PRV. In addition, this is also the first study to elucidate the interactions between PRV VP11/12 and EP0 as well as between PRV VP11/12 and STING, while identifying the precise interaction sites of PRV VP11/12 and VP16.

Identification of two novel epitopes targeting glycoprotein E of pseudorabies virus using monoclonal antibodies.

Pseudorabies virus (PRV), the agent of pseudorabies, has raised considerable attention since 2011 due to the outbreak of emerging PRV variants in China. In the present study, we obtained two monoclonal antibodies (mAbs) known as 2E5 and 5C3 against the glycoprotein E (gE) of a PRV variant (JS-2012 strain). The two mAbs reacted with wild PRV but not the vaccine strain (gE-deleted virus). The 2E5 was located in 161RLRRE165, which was conserved in almost of all PRV strains, while 5C3 in 148EMGIGDY154 was different from almost of all genotype I PRV, in which the 149th amino acid is methionine (M) instead of arginine (R). The two epitopes peptides located in the hydrophilic region and reacted with positive sera against genotype II PRV (JS-2012), which suggests they were likely dominant B-cell epitopes. Furthermore, the mutant peptide 148ERGIGDY154 (genotype I) did not react with the mAb 5C3 or positive sera against genotype II PRV (JS-2012). In conclusion, both mAb 2E5 and 5C3 could be used to identify wild PRV strains from vaccine strains, and mAb 5C3 and the epitope peptide of 5C3 might be used for epidemiological investigation to distinguish genotype II from genotype I PRV.

Ir(III)-Catalyzed Direct C-H Functionalization of Arylphosphine Oxides: A Strategy for MOP-Type Ligands Synthesis.

Diazo compounds as coupling partners are efficiently applied to Ir(III)-catalyzed direct C-H functionalization of arylphosphine oxides. Involving C-H activation, carbene insertion, and tautomerism, this reaction proceeds under mild conditions, thus proving an approach to the synthesis of MOP-type ligand precursor in a single step. The utility of this transformation has been further demonstrated in ligand synthesis as well as in the construction of phosphole framework.

Variations in glycoprotein B contribute to immunogenic difference between PRV variant JS-2012 and Bartha-K61.

A newly emerged pseudorabies virus (PRV) variant has been identified in many Bartha-K61-vaccinated pig farms. This variant has caused great economic losses to the swine industry in China since 2011. Sequence analysis demonstrated that the gB gene of the emerging PRV variant JS-2012 had multiple variations compared with the vaccine strain Bartha-K61. In the study, a specific CRISPR/Cas9 system combined with homologous recombination was used to construct two recombinant viruses, BJB (Bartha-K61+JS-2012gB) and JBJ (JS-2012-ΔgE/gI+Bartha-K61gB), by interchanging the full-length gB genes between Bartha-K61 and JS-2012-ΔgE/gI. The two recombinant viruses showed similar characteristics in growth kinetics in vitro and similar pathogenicity in mice, as compared to their parental strains. Immunization of mice with inactivated BJB or JBJ followed by challenge of JS-2012 showed that BJB could increase protective efficacy to 80%, compared to only 40% protection by the parental Bartha-K61 strain. JBJ had a decreased protective efficacy of 65%, as compared to 90% protection by its parental JS-2012-ΔgE/gI strain. Exchange of the gB gene markedly altered the immunogenicity of the recombinant PRV. These data suggest that variations in gB might play an important role in the virulence of the reemergent PRV variant in China. Our results demonstrate the importance of gB in protective immunity and suggest that the recombinant virus BJB could be a promising vaccine candidate for eradication of the PRV variant.