Intranuclear localization of human papillomavirus 16 E7 during transformation and preferential binding of E7 to the Rb family member p130

To study intracellular pathways by which the human papillomavirus 16 oncoge ne E7 participates in carcinogenesis, we expressed an inducible chimera of E7 by fusion to the hormone-binding domain of the estrogen receptor. The ch imeric protein (E7ER) transformed rodent fibroblast cell lines and induced DNA synthesis on addition of estradiol. In coimmunoprecipitation experiment s, E7ER preferentially bound p130 when compared to p107 and pRb, After estr adiol addition, E7ER localization changed to a more intense intranuclear st aining. Induction of E7 function was not correlated with binding to p130 or pRb but rather with intranuclear localization and modest induction of bind ing to p107.