Role Played by the Aggresome Pathway During Formation of ASFV Assembly Sites.

Assembly of African swine fever virus (ASFV) occurs in discrete perinuclear inclusion bodies called viral factories. Interestingly, cells produce similar inclusions called aggresomes in response to misfolded proteins. Aggresomes and viral factories are both located close to the microtubule organising centre (MTOC) and require an intact microtubular network for assembly. Both structures also recruit mitochondria, vimentin and cellular chaperones. This thesis investigates the interaction between ASFV and the aggresome pathway. Early ASFV gene products were observed in cells containing aggresomes, however, aggresomes prevented late ASFV gene expression, and the formation of virus factories. The results demonstrate competition between aggresomes and ASFV for components of the aggresome pathway. Aggresomes and virus factories rearrange vimentin into cages that surround perinuclear inclusions. During ASFV infection vimentin was first rearranged into an aster at the MTOC. This was independent of late viral gene expression, but required intact microtubules and the motor protein, dynein. The vimentin aster was then rearranged into a cage following synthesis of viral DNA, and late viral structural proteins. Vimentin rearrangement in cells generally requires phosphorylation. Antibodies raised against specific phosphoserine residues showed that vimentin was phosphorylated on serine 82 by Calcium/calmodulin dependent protein kinase II during ASFV infection. Phosphorylation of serine 82 was not necessary for the formation of vimentin cage, however, activation of Calcium/calmodulin dependent protein kinase II was required for late ASFV gene expression.