Abstract
Purpose :
We previously have shown that UL20 binds to HSV-1 gK, while gK binds to signal peptide peptidase. Thus, the goal of this study was to determine if similar to gK, UL20 binds to a cellular protein and if this interaction contributes to HSV-1 infectivity and pathogenesis.
Methods :
The Bacterial two-hybrid assay using UL20 as bait and a mouse neuronal cDNA library as a target, was used to identify putative protein binding partners of UL20. This binding was confirmed by co-immunoprecipitation and fluorescent colocalization in HeLa and RS cell lines. Blocking Zinc-finger-UL20 interaction was assayed using Zinc-finger protein dominant negative mutant, and Zinc-finger protein chemical inhibitor. The effect of Zinc-finger protein blocking on viral replication was monitored using standard plaque assay, quantitative real-time PCR and immunohistochemistry. Ocular HSV-1 replication and latency was evaluated in knockout mice lacking Golgi-specific Zinc-finger protein.
Results :
Using the two-hybrid system we identified Golgi-specific Zinc-finger protein as a putative cellular protein that binds to UL20. This binding of UL20 to the Zinc-finger protein was confirmed by pull-down assays and IHC. Blocking Zinc-finger protein binding to UL20 using a Zinc-finger protein dominant negative mutant or inclusion of a chemical Zinc-finger protein inhibitor significantly reduced HSV-1 replication in vitro by altering UL20 interaction with gK and their localization in infected cells. Finally, HSV-1 latency-reactivation in the trigeminal ganglia of latently infected knockout mice was significantly reduced in comparison to wild-type animals.
Conclusions :
We have demonstrated for the first time that HSV-1 UL20 interacts with Golgi-specific Zinc-finger protein and this interaction is required for virus infectivity as blocking this interaction reduces virus replication in vitro and in vivo. As there is currently no effective treatment for HSV-1 recurrences, blocking Zinc-finger protein-UL20 interaction may represent a clinically effective and expedient target in developing HSV-1 therapeutics.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.