NUCLEAR TARGETING OF SV40 AND ADENOVIRUS

Import of viral DNA into the nucleus is essential for the successful r eplication of DNA tumour viruses. To achieve this goal, viruses have a dapted strategies to traverse the barriers between the plasma membrane and the nucleus of a host cell. Two DNA tumour viruses, simian virus 40 and adenovirus, achieve the nuclear-entry step in slightly differen t ways. SV40 DNA enters the nucleus through the nuclear pore complexes (NPCs) in apparently intact virions. By contrast, adenovirus particle s dissociate near the NPC before the viral DNA is imported into the nu cleus. In both cases, karyophilic protein components of the viruses ap pear to mediate nuclear entry of the viral genomes. In this article, w e discuss how an understanding of the cell biology of vints entry can help us understand the process of nuclear transport.