Untersuchung des pUL31 und pUL34 unabhängigen Kernaustritts des Pseudorabies Virus The nuclear egress of nucleocapsids is an essential step in the herpesviral replication cycle. Due to its size the capsid cannot exit the nucleus through the nuclear pores but instead is transported through the nuclear membrane. The viral proteins pUL34 and pUL31 form the nuclear egress complex (NEC) which recruits cellular and viral kinases to the nuclear membrane. There they phosphorylate lamins which results in the local dissolution of the nuclear lamina and allows access of the nucleocapsids to the nuclear membrane. Deletion of one or both components of the NEC causes a significant reduction in viral titers but even in absence of the NEC a few infectious virions are produced which were used for reversion analysis. Therefore first the UL34 negative and later also the UL31 negative PrV were passaged on rabbit kidney cells (RK13) until titers in the supernatant were similar to PrV wildtype. From this supernatant single plaques were picked. These viruses replicated efficiently in the absence of the NEC and were designated as PrV UL34Pass and PrV UL31Pass respectively. Ultrastructural analysis showed that the passaged viruses were not transported through the nuclear membrane like PrV wildtype but through a fragmented nuclear envelope thereby releasing nucleocapsids into the cytosol. The aim of this study was to examine how nuclear egress functions without the NEC. In order to identify the mutated viral proteins which are important for nuclear envelope breakdown ... Herpesvirus Pseudorabies Virus Fragmentierung der Kernmembran Passagieren ERK Signalkaskade nuclear envelope breakdown