Contribution of the Golgi apparatus in morphogenesis of a virus induced cytopathic vacuolar system

The Golgi apparatus (GA) in mammalian cells is pericentrosomally anchored and exhibits a stacked architecture. During infections by members of the alphavirus genus, the host cell GA is thought to give rise to distinct mobile pleomorphic vacuoles known as CPV-II (cytopathic vesicle-II) via unknown morphological steps. To dissect this, we adopted a phased electron tomography approach to image multiple overlapping volumes of a cell infected with Venezuelan equine encephalitis virus (VEEV) and complemented it with localization of peroxidase tagged Golgi marker. Analysis of the tomograms revealed a pattern of progressive cisternal bending into double-lamellar vesicles as a central process underpinning the biogenesis and the morphological complexity of this vacuolar system. Here we propose a model for the conversion of GA to CPV-II that reveals a unique pathway of intracellular virus envelopment. Our result has implications for alphavirus virus induced displacement of Golgi cisternae to the plasma membrane to aid viral egress operating late in the infection cycle.