Amino Acid Substitutions in the Herpes Simplex Virus Transactivator VP16 Uncouple Direct Protein-Protein Interaction and DNA Binding from Complex Assembly and Transactivation *

The herpes simplex virus transactivator VP16 directs the assembly of a multicomponent protein-DNA complex that requires the participation of two cellular factors, the POU homeodomain protein Oct-1, which binds independently to response elements, and VCAF-1 (VP16 complex assembly factor; also called HCF, C1), a factor that binds directly to VP16. A number of distinct properties of VP16 have been implicated in the assembly of the VP16-induced …