RNA helicase DDX3X modulates herpes simplex virus 1 nuclear egress

Abstract

DDX3X is a mammalian RNA helicase that regulates RNA metabolism, cancers, innate immunity and several RNA viruses. We discovered that herpes simplex virus 1, a nuclear DNA replicating virus, redirects DDX3X to the nuclear envelope where it surprisingly modulates the exit of newly assembled viral particles. DDX3X depletion also leads to an accumulation of virions in intranuclear herniations. Mechanistically, we show that DDX3X physically and functionally interacts with the virally encoded nuclear egress complex at the inner nuclear membrane. DDX3X also binds to and stimulates the incorporation in mature particles of pUs3, a herpes kinase that promotes viral nuclear release across the outer nuclear membrane. Overall, the data highlights two unexpected roles for an RNA helicase during the passage of herpes simplex viral particles through the nuclear envelope. This reveals a highly complex interaction between DDX3X and viruses and provides new opportunities to target viral propagation.

Direct Relationship between Protein Expression and Progeny Yield of Herpes Simplex Virus 1 Unveils a Rate-limiting Step for Virus Production

“…6B). The frequencies of each type of nuclear capsid in subpopulations f4 and f5 were similar to those reported previously in wild-type HSV-1-infected HeLa cells 30 . Furthermore, the aberrant accumulation of B capsids and lack of nuclear C capsids and virions in the perinuclear space and cytoplasm in subpopulation f3 were also observed at 8h post-infection (S-Figs.…”

“…5B). The frequencies of each type of nuclear capsid in subpopulations f4 and f5 were similar to those reported previously in wild-type HSV-1-infected HeLa cells 30 . These features of subpopulation f3 were similar to the phenotypes of HSV-1 mutants with defective viral DNA genome cleavage/packaging including those lacking the portal protein UL6, a terminase subunit (UL15, UL33 or UL28) or a minor capsid protein (UL17 or UL32) [31][32][33][34][35][36][37] .…”

Comprehensive Proteomic Analysis of HCoV-OC43 Virions and Virus-Modulated Extracellular Vesicles

“…In contrast, our lab and others have developed a targeted proteomic pipeline that scrutinizes the protein content of highly purified viral particles (39)(40)(41)(42)(43)(44). Although this approach is less explored, it is pertinent as many viruses incorporate host molecules, some of which are biologically active (45)(46)(47)(75)(76)(77)(78)(79).…”

“…In contrast, our lab and others have developed a targeted proteomic pipeline that scrutinizes the protein content of highly purified viral particles (39–44). Although this approach is less explored, it is pertinent as many viruses incorporate host molecules, some of which are biologically active (45–47, 75–79). Our focused proteomic method has several advantages, including a limited number of identified targets that simplifies subsequent functional analyses.…”

“…Unfortunately, these large-scale approaches are costly, suffer from limited reproducibility (37, 38) and produce large numbers of candidates making molecular characterization difficult. Our approach, along with others, has focused on analyzing the protein content of viral particles, identifying several host proteins (39–44), some of which are active in viral propagation (45) and have revealed unexpected functions (46, 47). Recent proteomics studies of SARS-CoV-2 virions have suggested that virion-incorporated G3BP1/2 stress granule modulators may play a role in the formation of the viral assembly sites (48).…”