Fig. 3.—

(A) Schematic map of the E2 and E4 genes. The E4 ORF overlaps the hinge region of the E2 gene. This region is a flexible, essentially disordered connector between the functionally conserved transcription activation domain and the DNA-binding domain. (B) Cumulative frequency plot of E2 and E4 genes, and the overlapping and nonoverlapping region of both genes. CAI values of each HPV gene were computed on the basis of CUPrefs in human genes. Code for genes: Orange, E2; brown, E4; violet, E2 hinge region; and green, E2 nonoverlapping region with E4.