Manipulation of Early Region 4.

Early region 4 (E4; Fig. 1A) occupies the right-hand 3000 bp of the human adenovirus genome. The sequences of E4 and E4 cDNAs indicate that E4 encodes seven polypeptides (1-4), most of which have been detected in infected cells. Analysis of E4 mutants has implicated E4 products in a variety of processes that occur in infected cells, including viral early and late gene expression, DNA replication, the shutoff of host-cell protein synthesis, transformation, and the ability to stimulate replication of adenovirus-associated virus (AAV). Specific E4 products have been implicated in many of those processes and, in some cases, information on the molecular mechanisms of E4 function is emerging. Current knowledge of the functions of E4 products is summarized below. [ABSTRACT FROM AUTHOR]