Investigating the biology of alpha herpesviruses with MS-based proteomics

Viruses are intracellular parasites that can only replicate and spread in cells of susceptible hosts. Alpha herpesviruses (alpha-HVs) contain double-stranded DNA genomes of at least 120 kb, encoding for 70 or more genes. The viral genome is contained in an icosahedral capsid that is surrounded by a proteinaceous tegument layer and a lipid envelope. Infection starts in epithelial cells and spreads to the peripheral nervous system. In the natural host, alpha-HVs establish a chronic latent infection that can be reactivated and rarely spread to the CNS. In the nonnatural host, viral infection will in most cases spread to the CNS with often fatal outcome. The host response plays a crucial role in the outcome of viral infection. alpha-HVs do not encode all the genes required for viral replication and spread. They need a variety of host gene products including RNA polymerase, ribosomes, dynein, and kinesin. As a result, the infected cell is dramatically different from the uninfected cell revealing a complex and dynamic interplay of viral and host components required to complete the virus life cycle. In this review, we describe the pivotal contribution of MS-based proteomics studies over the past 15 years to understand the complicated life cycle and pathogenesis of four alpha-HV species from the alphaherpesvirinae subfamily: Herpes simplex virus-1, varicella zoster virus, pseudorabies virus and bovine herpes virus-1. We describe the viral proteome dynamics during host infection and the host proteomic response to counteract such pathogens.