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

Abstract

Herpes simplex virus 1 (HSV-1) infection manipulates distinct host DNA-damage responses to facilitate virus proliferation, but the molecular mechanisms remain to be elucidated. One possible HSV-1 target might be DNA damage-tolerance mechanisms, such as the translesion synthesis (TLS) pathway. In TLS, proliferating cell nuclear antigen (PCNA) is monoubiquitinated in response to DNA damage-caused replication fork stalling. Ubiquitinated PCNA then facilitates the error-prone DNA polymerase η (polη)-mediated TLS, allowing the fork to bypass damaged sites. Because of the involvement of PCNA ubiquitination in DNA-damage repair, we hypothesized that the function of PCNA might be altered by HSV-1. Here we show that PCNA is a substrate of the HSV-1 deubiquitinase UL36USP, which has previously been shown to be involved mainly in virus uptake and maturation. In HSV-1-infected cells, viral infection-associated UL36USP consistently reduced PCNA ubiquitination. The deubiquitination of PCNA inhibited the formation of polη foci and also increased cell sensitivity to DNA-damage agents. Moreover, the catalytically inactive mutant UL36C40A failed to deubiquitinate PCNA. Of note, the levels of virus marker genes increased strikingly in cells infected with wild-type HSV-1, but only moderately in UL36C40A mutant virus-infected cells, indicating that the UL36USP deubiquitinating activity supports HSV-1 virus replication during infection. These findings suggest a role of UL36USP in the DNA damage-response pathway.

Epstein-Barr Virus Early Protein BFRF1 Suppresses IFN-β Activity by Inhibiting the Activation of IRF3

“…Statistical analysis was performed using Student's t test. ns, not significant; *P < 0.05; **P < 0.01; ***P < 0.001. applied in many studies (70,(77)(78)(79)(80), IRF3 was localized exclusively in the cytoplasm in mock-infected HeLa cells, while most of IRF3 translocated into the nucleus after SeV stimulation. However, IRF3 was restricted in the cytoplasm in BFRF1 expressing cells.…”

Herpes Simplex Virus 1 UL2 Inhibits the TNF-α–Mediated NF-κB Activity by Interacting With p65/p50

“…After TNF-α binds to TNFR, IκBα is phosphorylated by IKKs, followed by its ubiquitination and degradation, and then the p65/p50 dimer was released and translocated into nucleus (30,35,36), which is important for the NF-κB activation. Here, HeLa cells, which are widely employed in different studies for indirect immunofluorescence assay as its nucleus, are obviously larger than cytoplasm (40,56,60,61,(65)(66)(67)(68)(69)(70)(71)(72)(73)(74), were used to test whether UL2 could block the nuclear translocations of p65 and p50. As shown in Figure 8 and statistical analysis of the subcellular localization in Table 2 that is widely applied in many studies (61,67,68,70,71), p65 and p50 were localized exclusively to the cytoplasm in the mock-stimulated HeLa cells, which were then translocated into the nuclei after TNF-α treatment.…”

Comparison of the Transcriptomes and Proteomes of Serum Exosomes from Marek’s Disease Virus-Vaccinated and Protected and Lymphoma-Bearing Chickens

“…A C98A, protease-dead mutation, in its USP catalytic site, leads to severe reduction in MD tumor incidence, although MDV replication was unaffected in vitro and in vivo. HSV1 USP was shown to deubiquitinate poly-ubiquitinated IκBα and mono-ubiquitinated PCNA to inhibit HSV1 DNA-induced IFN-β or NF-κB activation and DNA damage responses, respectively, to facilitate infection [ 69 , 70 ].…”