Interplay between the cellular restriction factor PML and dengue virus

CYBELE C. GARCÍA; FEDERICO GIOVANNONI; ELSA DAMONTE

Austin, Texas

Simposio; Positive-Strand RNA Viruses; 2016

Keystone Symposia

Intrinsic immunity is a form of innate immunity that provides a potent protection from viral infection. It is mediated by constitutively-expressed cellular proteins, known as restriction factors, that block viral replication immediately.Promyelocytic leukemia (PML) protein contributes to intrinsic immunity against many viruses. PML forms nuclear bodies (NB) that serve as a hub for the interaction of over 100 proteins. Many viral proteins disrupt NB. This has led to the hypothesis that the disruption of NB may be a viral strategy to evade the host antiviral response.We have previously reported the antiviral role of PML against dengue virus serotype 2 (DENV2). Here, we performed further studies to characterize the antiviral role of PML in the in vitro replication of other DENV serotypes (DENV1-4) as well as the molecular mechanism behind this effect.Intracellular localization of NB in A549 cells during DENV infection was analyzed by immunofluorescence. These studies showed that NB were not altered during early infection (18 h), NB underwent a rearrangement. In particular, the number of NB per nucleus was significantly lower in DENV infected cells compared to controls.To determine if the disruption of NB during DENV infection could be a consequence of the interaction between PML and a viral component, cells were transfected with vectors expressing C or NS5 DENV2 proteins. C and NS5 have been shown to localize to the nucleus and therefore were considered likely candidates for interaction with PML.Confocal images showed that expression of C did not alter the typical punctuate pattern of NB. However, expression of NS5 correlated with a diminished count of NB per cell nucleus.Overall, we show for the first time the interplay between PML and DENV1-4. Moreover, our data suggest that NS5 could be involved in NB disassembly. However, more studies are required in order to fully understand PML-DENV interaction.