Simian virus 40 infection disrupts p130-E2F and p107-E2F complexes but does not perturb pRb-E2F complexes

In its native host species, the Rhesus Macaque, simian virus 40 (SV40) forms a persistent infection in the kidneys with no apparent harmful side effects. We show that SV40 infection of growth-arrested monkey kidney epithelial cells results in the specific disruption of certain Rb-E2F family complexes. Throughout the course of infection, p130-E2F and p107-E2F complexes are disrupted, but surprisingly pRb-E2F complexes remain intact. This suggests that the presence of some pRb-E2F complexes is not inhibitory to productive infection. Additionally, while a decrease of p130 steady state levels is observed during the later time points of infection, early during infection, p130 is readily detectable. This suggests SV40 infection overrides p130-mediated growth arrest through a mechanism(s) in addition to the well-documented T antigen-mediated degradation of p130. Finally, infection induces a dramatic relocalization of E2F4 from the nucleus to the cytoplasm. The implications of these observations to the life cycle of the virus are addressed.