Aggresomes resemble sites specialized for virus assembly

The large cytoplasmic DNA viruses such as poxviruses, iridoviruses, and Afr ican swine fever virus (ASFV) assemble in discrete perinuclear foci called viral factories. Factories exclude host proteins, suggesting that they are novel subcellular structures induced by viruses. Novel perinuclear structur es, called aggresomes are also formed by cells in response to misfolded pro tein (Johnston; J.A., C.L. Ward, and R,R, Kopito, 1998. J. Cell Biol. 143:1 883-1898: Garcia-Mata, R., Z. Bebok, E.J Sorscher, and E.S, Sztul, 1999. J. Cell Biol. 146: 1239-1254). In this study we have investigated whether agg resomes and viral factories are related structures. Aggresomes were compare d with viral factories produced by ASFV. Aggresomes and viral factories wer e located close to the microtubule organizing center and required an intact microtubular network for assembly. Both structures caused rearrangement of intermediate filaments and the collapse of vimentin into characteristic ca ges, and both recruited mitochondria and cellular chaperones. Given that AS FV factories resemble aggresomes, it is possible that a cellular response o riginally designed to reduce the toxicity of misfolded proteins is exploite d by cytoplasmic DNA viruses to concentrate structural proteins at virus as sembly sites.