FIG 1.

K111 is necessary for transient viral replication. Mutations of E2 lysine 111 (K111) alter transient replication. (A) Sequence alignment shows the highly conserved K111. (B) C33A cells were cotransfected with BPV1 E2-K111 mutants, pFLORI-BPV1, and pRRL and (C) C33A cells were cotransfected with HPV31 E2-K111 mutants. E2 mutants were cotransfected with pFLOri31. The luminescence was normalized to Renilla luciferase and the respective background E2 luminescence. Each of the samples was normalized to its respective control without E1 to cancel out any background effect. (Inset) The effect of K111R mutation on cell viability and cell cycle was determined by flow cytometry. (D) 293TT cells were cotransfected with HPV31 FLAG-E2 and HA-E1. E1 protein pulldown was conducted using 12CA5 antibody and blotted with HA7 and M2 antibodies. *, P < 0.05; **, P < 0.005.