Varicella-zoster virus infection facilitates VZV glycoprotein E trafficking to the membrane surface of melanoma cells

Abstract

Varicella-zoster virus glycoprotein E (gE) is the most abundant VZV glycoprotein on the surface of virus-infected cells. VZV gE has targeting sequences for the trans-Golgi network (TGN) and is transported from the ER to the TGN in infected and gE-transfected cells. In this study, VZV gE expressing melanoma cell lines were generated. gE is expressed under the control of the reverse Tet repressor (Tet-On). gE induced by Tet-On is retained at the ER as well as in the cis Golgi by immunofluorescence confocal microscopy. To test whether other viral protein(s) may facilitate gE trafficking and surface localization, MSPgE-vOka virus that contains MSPgE in place of wt gE was made. MAb 3B3 anti-gE does not bind to MSPgE. This MAb was used to track the localization of gE in Met-gE cells post MSPgE-vOka infection. gE became detectable mostly at the TGN and on the cell surface after viral infection. These data indicate that viral proteins facilitate the trafficking and cell surface expression of gE.

Varicella‐Zoster virus ORF9 is an antagonist of the DNA sensor cGAS

“…We could detect low levels of CXCL10 in supernatants from IRF3‐KO cells, but there was no increase above baseline after infection. Analysis of co‐cultured cells by flow cytometry (cell‐surface staining for the VZV‐gE/gI complex (Mo et al , 2003 )) showed that the proportion of inoculum MeWo cells and THP1 target cells differed between samples, in particular for uninfected conditions (Fig EV1 E and F). Within the population of THP1 target cells, the percentage of VZV‐infected cells was variable and no clear differences between THP1‐KO cell lines could be observed (Fig EV1 E and G).…”

“…MeWo cells do not induce type I IFNs in response to VZV (Figure 1). Infected cells within the target cell population were identified by cell-surface staining for the VZV glycoprotein E (gE)/glycoprotein I (gI) complex (Figure S3B) (Mo et al, 2003). Due to the nature of the co-culture, cells harvested for RT-qPCR and immunoblotting contained both target and inoculum cells.…”

Varicella-Zoster Virus ORF9 Is an Antagonist of the DNA Sensor cGAS

“…WT, cGAS KO, and MAVS KO THP1 (Figure 1B) cells were infected for 24 and 48 hours using this transwell assay. Cell-surface staining for the VZV-gE/gI complex and flow cytometry analysis (Mo et al, 2003) revealed significantly higher levels of infection in cGAS KO cells compared to WT and MAVS KO cells at both time points (Figures 1C and S4). We further found increased expression of immediate early (IE), early (E), and late (L) viral gene products in cells lacking cGAS (Figure 1D).…”

“…MeWo cells do not 129 induce type I IFNs in response to VZV ( Figure 1). Infected cells within the target cell 130 population were identified by cell-surface staining for the VZV glycoprotein E 131 (gE)/glycoprotein I (gI) complex ( Figure S3B) (Mo et al, 2003). 132…”