Rearrangement of intermediate filament network of BHK-21 cells infected with vaccinia virus.

Association between vaccinia virus (VV) structures and intermediate filaments in specific areas of the cytoplasm of infected cells (virus "factories") suggests that VV infection interferes with the cellular architecture by modifying the intermediate filament network. To analyse this question, we examined the array of intermediate filaments of BHK-21 cells infected with VV by laser scanning confocal microscopy using an anti-vimentin mouse monoclonal antibody. We observed a marked reorganization of intermediate filaments around the nucleus of infected cells. Bidimensional analysis of 32PO4-labeled intermediate filament proteins revealed that the acidic isoform of vimentin and two isoforms of desmin have increased phosphorylation levels in infected cells. Our results suggest that the reorganization of intermediate filaments observed during VV infection could be promoted by an increase in the phosphorylation level of the intermediate filament proteins, vimentin and desmin.