Co-opting the Fanconi Anemia Genomic Stability Pathway Enables Herpesvirus DNA Synthesis and Productive Growth

Abstract

SUMMARY DNA damage associated with viral DNA synthesis can result in double strand breaks that threaten genome integrity and must be repaired. Here, we establish that the cellular Fanconi Anemia (FA) genomic stability pathway is exploited by HSV1 to promote viral DNA synthesis and enable its productive growth. Potent FA pathway activation in HSV1-infected cells resulted in monoubiquitination of FA effector proteins, FANCI and FANCD2 (FANCI-D2) and required the viral DNA polymerase. FANCD2 relocalized to viral replication compartments and FANCI-D2 interacted with a multi-subunit complex containing the virus-encoded single-stranded DNA-binding protein ICP8. Significantly, while HSV1 productive growth was impaired in monoubiquitination-defective FA patient cells, this restriction was partially surmounted by antagonizing the DNA-dependent protein kinase (DNA-PK), a critical enzyme required for non-homologous end-joining (NHEJ). This identifies the FA-pathway as a new cellular factor required for herpesvirus productive growth and suggests that FA-mediated suppression of NHEJ is a fundamental step in the viral lifecycle.

G 2 /M Cell Cycle Arrest Correlates with Primate Lentiviral Vpr Interaction with the SLX4 Complex

“…This suggests a potential interplay between this nuclear DNA repair pathway and the suppression of innate immune sensing of "dangerous" nuclear DNA. Interestingly, a recent study has demonstrated that late replication events of herpes simplex virus 1 (HSV-1) require an intact Fanconi anemia repair pathway and that, in its absence, viral replication is restricted in part by the nonhomologous end-joining pathway (NHEJ) that deals with double-stranded breaks (DSBs) in nuclear DNA (31). Vpr expression has been shown to promote H2AX␥ foci in the nucleus (28), a marker of DSBs, as well as the FANCD2 foci that are hallmarks of ICL repair (15).…”

The herpes simplex virus 1 UL36USP deubiquitinase suppresses DNA repair in host cells via deubiquitination of proliferating cell nuclear antigen

“…Previous studies indicate that HSV-1 regulates DDR pathways when the viral genome is transported to the cell nucleus. HSV-1 infection is found to increase single strand annealing and the Fanconi anemia (FA) pathway while decreasing homologous recombination (HR), non-homologous end joining (classic NHEJ), and microhomology-mediated end joining (MMEJ) pathways, although the detailed mechanisms remained to be elucidated (37,38). In addition to these pathways, our data here indicates that the TLS pathway is also suppressed by HSV-1 through the deubiquitination activity of UL36USP, adding a new member into the cellular DDR network manipulated by HSV-1 infection.…”

HSV-I and the Cellular DNA Damage Response

“…In addition, both ICP8 and UL12 have been shown to interact with many DDR proteins [39,42–44]; however, attempts to identify the precise roles played by these proteins in HSV DNA replication have not been straightforward. For instance, although HSV may take advantage of cellular components to promote viral DNA replication, many DDR pathways promote antiviral mechanisms such as silencing and the induction of innate immune signaling.…”

“…Recently, the Mohr lab demonstrated that FA proteins are necessary for efficient HSV-1 replication and transcription and suggested that these proteins act as regulators of DNA repair pathway choice during infection [44]. HSV-1 potently activates the FA pathway, by monoubiquitination of FANCI-D2, which seems to require HSV pol and DNA replication (Figure 2) [44].…”

“…HSV-1 potently activates the FA pathway, by monoubiquitination of FANCI-D2, which seems to require HSV pol and DNA replication (Figure 2) [44]. In addition, they demonstrated that FANCI interacts with ICP8, pol, UL42, UL12 and dUTPase and that FANCD2 interacts with the helicase subunit, UL5 [44].…”