Duck enteritis virus UL21 is a late gene and encodes a protein that interacts with pUL16

Abstract

Background pUL21 is a conserved protein of Alphaherpesvirinae and exhibits multiple important functions. The C-terminus of pUL21 in other members of this subfamily has RNA-binding ability; this domain contributes to pseudorabies virus (PRV) retrograde axonal transport in vitro and in vivo and participates in newly replicated viral DNA packaging and intracellular virus transport. However, little is known about duck enteritis virus (DEV) pUL21. Methods In our study, recombinant pUL21 was expressed using apET-32c (+) vector in Escherichia coli BL21 cells induced with 0.4 mM isopropyl β-D-thiogalactoside for 8 h at 30°C. The antibody for indirect immunofluorescence (IFA) and western blotting (WB) analysis were then prepared. Pharmacological inhibition, WB and quantitative reverse transcription PCR (RT-qPCR) were performed. A coimmunoprecipitation (CO-IP) assay was conducted to test the interaction between pUL21 and pUL16. Results We verified that DEV UL21 is a γ2 gene and encodes a structural protein. Moreover, we observed that pUL21 localized to the nucleus and cytoplasm. DEV pUL21 interacted with pUL16 and formed a complex in transfected human embryonic kidney (HEK) 293T cells and DEV-infected duck embryo fibroblasts (DEFs). These results were further confirmed by CO-IP assays. Conclusions The DEV UL21 gene is a late gene, and the pUL21 localizes to the nucleus and cytoplasm. DEV UL21 is a virion component. In addition, pUL21 can interacts with pUL16. These findings provide insight into the characteristics of UL21 and the interaction between pUL21 and binding partner pUL16. Our study enhances understanding of DEV pUL21.