Abstract
Bluetongue virus (BTV), a non-enveloped arbovirus, causes hemorrhagic disease in ruminants. However, the influence of natural host cell proteins on BTV replication process is not defined. In addition to cell lysis, BTV also exits non-ovine cultured cells by non-lytic pathways mediated by nonstructural protein NS3 that interacts with virus capsid and cellular proteins belonging to calpactin and ESCRT family. The PPXY late domain motif known to recruit NEDD4 family of HECT ubiquitin E3 ligases is also highly conserved in NS3. In this study using a mixture of molecular, biochemical and microscopic techniques we have analyzed the importance of ovine cellular proteins and vesicles in BTV infection. Electron microscopic analysis of BTV infected ovine cells demonstrated close association of mature particles with intracellular vesicles. Inhibition of Multi Vesicular Body (MVB) resident lipid phosphatidylinositol-3-phosphate resulted in decreased total virus titre suggesting that the vesicles might be MVBs. Proteasome mediated inhibition of ubiquitin or modification of virus lacking the PPXY in NS3 reduced virus growth. Thus, our study demonstrated that cellular components comprising of MVB and exocytic pathways proteins are involved in BTV replication in ovine cells.
Highlights
Cell membranes present significant dissemination barriers and viruses have developed sophisticated mechanisms for entering and exiting cells
Most studies on virus and host cell interactions have been undertaken in cells that have originated from species that are not the natural virus host
This study describes Bluetongue virus (BTV) infection of PT, a sheep kidney cell line and elucidates the role of cellular proteins in differential virus release
Summary
Cell membranes present significant dissemination barriers and viruses have developed sophisticated mechanisms for entering and exiting cells. While enveloped viruses bud through membranes, non-enveloped viruses are believed to be predominantly released by cell lysis. Recently alternate routes involving non-lytic pathways of exit have been noted for non-enveloped viruses [1,2,3,4]. Bluetongue virus (BTV), a member of the Reoviridae family, is a double capsid complex non-enveloped orbivirus that infects ruminants via biting gnats (Culicoides sp). Like other members of the family, BTV egress in mammalian cells predominantly occurs by cell lysis. BTV exhibits budding morphology similar to enveloped viruses and can be released as enveloped particles [5,6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
