FIG 4.

HPV31 E2-K111 mutants maintain interactions with cellular factors. (A) 293TT cells were cotransfected with HPV31 FLAG-E2, and plasmids expressing BRD4 fragments CTM, BID, and PDID. BRD4 proteins were pulled down using glutathione S-transferase (GST) antibody and blotted with GST and M2 antibodies. (B) 293TT cells were cotransfected with HPV31 FLAG-E2 and HA-GPS2. HPV31 E2 protein pulldown was executed with M2 antibody and blotted with HA7 and M2 antibodies. Relative GPS2 binding was calculated by densitometry and presented graphically. (C) 293TT cells were transfected with HPV31 FLAG-E2 followed by E2 protein immunoprecipitation with M2 antibody. The amounts of endogenous TopBP1 coimmunoprecipitated were determined by blotting with anti-TopBP1 and anti-M2 antibodies, and relative binding was calculated by densitometry and represented graphically.