Validation of conserved and specific interactions with HPV E7s. (A) N/Tert-1 cells expressing E7-FlagHA or HA-HPV18 E2 (Top, HA Western blot) were subjected to IP with HA antibody. Immunoprecipitates were separated by SDS/PAGE and Western blotted by using antibodies to RB1, UBR4, KCMF1, ENC1, and ZER1. (B) Additional N/Tert-1 cell lines expressing E7-FlagHA were subjected to IP with HA antibody. Immunoprecipitates were separated by SDS/PAGE and Western blotted by using antibodies to HA, RB1, and ZER1.