Forms a multivalent network in host nucleus that inhibits nuclear bodies and prevents antiviral cellular activities. The network is made of multimerized dimers and surrounds adenovirus replication centers and nucleolus. Plays a role in splicing of the major late transcript. Prevents viral genome concatemer formation. Homodimer. Multimerizes through C-terminus tail by reciprocal or nonreciprocal interactions. Interacts with host PML isoform 2 C-terminal disordered region. Interacts with E1B-55k; this interaction is necessary for E1B 55 kDa protein to localize to the nuclear matrix fraction of the cell (PubMed:10211970). May interact with host TRIM24, CREBBP, EP300, PRKDC and the MRN complex MRE11/RAD50/NBS1; these interactions may happen through nuclear bodies complexes. forms networks in the nucleus that may surround adenovirus replication centers. Synthesized early during infection. Belongs to the adenoviridae E4 ORF3 family.