The full-length E2 protein expressed from the entire E2 open reading frame (ORF) consists of a conserved N-terminal terminal “transactivation” domain of about 200 amino acids linked to a C- terminal DNA binding/dimerization domain of about 100 amino acids. The two domains are connected by a flexible linker sequence, often called the “hinge” (Giri and Yaniv, 1988; McBride et al., 1989b, 1988), which varies in length and sequence composi- tion among different genera of papillomaviruses