The HPV early proteins E1, E2, E6 and E7 that have been validated as potential antiviral targets are represented by boxes. The locations of specific functional domains discussed in this review are indicated and their activities listed underneath. Because the length of each protein can vary slightly between viral types, an approximate length in amino acids (aa) is indicated at the right of each protein. DBD, DNA-binding domain; H, hinge region; HDAC, histone deacetylase; NES, nuclear export sequence; NLS, nuclear localization sequence; TAD, transactivation domain; Zn, zinc finger.