Zika virus replication in glioblastoma cells: electron microscopic tomography shows 3D arrangement of endoplasmic reticulum, replication organelles, and viral ribonucleoproteins

Abstract

Structural changes of two patient-derived glioblastoma cell lines after Zika virus infection were investigated using scanning transmission electron tomography on high-pressure-frozen, freeze-substituted samples. In Zika-virus-infected cells, Golgi structures were barely visible under an electron microscope, and viral factories appeared. The cytosol outside of the viral factories resembled the cytosol of uninfected cells. The viral factories contained largely deranged endoplasmic reticulum (ER), filled with many so-called replication organelles consisting of a luminal vesicle surrounded by the ER membrane. Viral capsids were observed in the vicinity of the replication organelles (cell line #12537 GB) or in ER cisternae at large distance from the replication organelles (cell line #15747 GB). Near the replication organelles, we observed many about 100-nm-long filaments that may represent viral ribonucleoprotein complexes (RNPs), which consist of the RNA genome and N protein oligomers. In addition, we compared Zika-virus-infected cells with cells infected with a phlebovirus (sandfly fever Turkey virus). Zika virions are formed in the ER, whereas phlebovirus virions are assembled in the Golgi apparatus. Our findings will help to understand the replication cycle in the virus factories and the building of the replication organelles in glioblastoma cells.

ARF1 prevents aberrant type I interferon induction by regulating STING activation and recycling

“…A series of tilted images of the sections from an angle of −72° to +72° with an increment of 1.5° were recorded using a Jeol FEM 2100 F field-emission TEM equipped with a Jeol STEM bright-field detector (Jeol Ltd) and, EM-Menu 4.0 STEM tomography software (TVIPS) at a resolution of 1024 px × 1024 px, an illumination time of 20 s, and an acceleration voltage of 200 kV. Alignment of the images with the gold particles as fiducial markers as well as 3D-reconstruction of the tilt series was done using the IMOD 4.9 software 80 , 81 .…”

Mechanisms of Zika astrocyte infection and neuronal toxicity

“…Overall, ZIKV is a member of Flaviviridae and produces both infectious and noninfectious virions. Subviral particles are common during Flavivirus infection and result in uptake, but not viral production, of new virions in host cells [ 61 ], [ 62 ], [ 63 ], [ 64 ], [ 65 ], [ 66 ]. To determine the ZIKV infectivity of human astrocytes at different fetal developmental stages were inoculated with ZIKV strain PA 259,459, an Asian lineage strain isolated from an infected human, Panama in 2015.…”

Cryo-Electron Tomography: The Resolution Revolution and a Surge of In Situ Virological Discoveries

“…These virus-induced safehouses for replication were then gradually recognized to be a strategy adopted by (+)RNA viruses (78). Further phenomena were observed in cells infected by flavivirus (121), alphavirus (60,108), and other coronaviruses (56,76).…”