Cytoskeleton involvement during human cytomegalovirus replicative cycle in human embryo fibroblasts.

Several studies indicate that viruses can induce different cytoskeletal modifications. The present investigation examines the possible involvement of human embryo fibroblast cytoskeleton in the replication of human cytomegalovirus (HCMV). Significant cytoskeletal modifications occur in infected cells; specifically, microfilament depolymerization is observed very early during the HCMV replicative cycle, whilst microtubules and intermediate filaments do not undergo any change for longer times after infection. Our data focus, in particular, on microfilament depolymerization, which starts within the first hour of the replicative cycle, and on the significance of this event, as a CMV-induced mechanism to modify the post-transcriptional regulation of cellular gene expression for its own benefit. Among the possible mechanisms exploited by HCMV to induce microfilament modifications, one might involve the cellular ADP-ribosylation activity, which is increased by HCMV very early in the infectious cycle. Experiments carried out on HCMV-infected cells, in the presence of ADP-ribosylation inhibitors, seem to confirm this hypothesis.