SUMO Modification Stabilizes Dengue Virus Nonstructural Protein 5 To Support Virus Replication.
Bottom Line: By expressing various NS5 mutants, we found that the SUMO acceptor sites are located in the N-terminal domain of NS5 and that a putative SUMO-interacting motif (SIM) of this domain is crucial for its SUMOylation.SUMOylation-defective mutants also failed to suppress the induction of STAT2-mediated host antiviral interferon signaling.Here, we found that the replicase of DENV, nonstructural protein 5 (NS5), can be SUMOylated.
Affiliation: Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.Show MeSH
Related in: MedlinePlus
Mentions: Since the SIM motif is required for NS5 SUMOylation, we next determined its potential biological roles in DENV infection. Huh7 cells stably expressing the control shRNA (Ctrl) or Ubc9-targeting shRNA (Fig. 4A) were transfected with in vitro-transcribed RNA derived from WT or a SIM-mutated DENV subgenomic replicon containing a luciferase reporter gene, which reflects the viral RNA replication level. By measuring the luciferase activity, we found that the replication level of WT replicon was consistently and significantly lower in the cells stably expressing Ubc9-targeting shRNA than that of control shRNA (Fig. 4B), suggesting that Ubc9 activity is required for DENV RNA replication. In contrast, with the SIM-mutated replicon, the luciferase activity was further reduced in both the control and Ubc9 knockdown cells. Collectively, these results suggested that Ubc9-mediated SUMOylation is required for DENV RNA replication, and this posttranslational modification relies on the presence of the putative SIM motif of DENV NS5.
Affiliation: Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.