Breaching the barrier - the nuclear envelope in virus infection

Many DNA and a few RNA viruses use the host cell nucleus for virion formation and/or genome replication. To this end, the nuclear envelope barrier has to be overcome for entry into and egress from the intranuclear replication compartment. Different virus families have devised ingenious ways of entering and leaving the nucleus usurping cellular transport pathways through the nuclear pore complex but also translocating directly through both membranes of the nuclear envelope. This intriguing diversity in nuclear entry and egress of viruses also highlights different ways nucleo-cytoplasmic transport can occur. Thus, the study of interactions between viruses and the nuclear envelope also helps to unravel hitherto unknown cellular pathways such as vesicular nucleo-cytoplasmic transfer.