Construction and Characterization of a novel PRV recombinant expressing a C Terminal VP26-mCherry fusion protein

Abstract

Fluorescent protein-based methodologies have revolutionized the field of virology, allowing us to visualize the location and activity of pseudorabies virus (PRV) particles in vitro (G. A. Smith & Enquist, 2002). Several limitations, including brightness and stability have limited such tools for microscopy analysis (Hogue et al., 2015). While N terminal fusions of fluorescent proteins to capsid proteins like VP26 (pUL35) have been well utilized, little is known about the effectiveness of C Terminal fusions. Included in this study are the first recombinant PRV strains expressing C terminal VP26-mCherry. The properties of this reporter virus, PRV 1028, were compared to previously constructed N terminal recombinants containing either mRFP or mCherry. PRV 1028 had similar single-step replication kinetics compared to wild-type PRV Becker and traditional FP– VP26 strains. Despite slightly reduced plaque diameter, we find that our newly synthesized PRV 1028 incorporates more fluorescent VP26 fusion proteins in progeny virus particles. As a result, PRV 1028 capsids have a higher fluorescent intensity in comparison to their N terminal counterparts. Based on these findings, our novel PRV recombinant will allow for optimized fluorescent-based methodologies.