However, while from 24 to 36 hpi the increase in viral DNA copies in the E1B null virus was minimal, all RNP mutants displayed increments that were comparable to Ad5 WT (Fig 7), suggesting that all but the deletion RNP mutant display a defect in the initial replication of viral DNA, and that the E1B 55K produced by the RNP mutants can support WT levels of viral DNA replication at later time-points of infection. Here, PSEN2 is linked to infection.