Role of E7 in HPV Infections

Indiana University Indianapolis, Indianapolis IN

Investigators

Linked publications & trials

Abstract

The long-term goal of our studies is to determine the mechanisms by which the E7 proteins of genital human papillomaviruses (HPV) contribute to the pathogenesis of viral infections. We have previously demonstrated an important role for E7 in the productive viral life cycle by acting to facilitate the maintenance of viral episomes. In the current grant period, we have demonstrated that by binding to HDACs, E7 specifically activates expression of E2F2 in differentiating cells and that this is important for activation of late gene expression. Additional work identified a role for E7 in activation of the ATM/ATR DNA damage response as well as caspases, both of which are necessary for productive replication in differentiating cells as is the activation of caspases. In further studies, we determined that E7 activates the hypoxia-inducible transcription factor (HIF-1) and that this may contribute to the ability of HPV lesions to grow and induce angiogenesis. These observations form the basis of the proposed studies to elucidate the many role of E7 in the viral life cycle. In this renewal application we will ask the following questions: 1). How does E7 activate the ATM pathway? How does ATM activation contribute to productive replication? 2). How does E7 activate caspases upon differentiation? Is this a result of ATM activation? 3). What is the mechanism by which E7 stabilizes HIF-1 levels? What is the contribution of E7 enhancement of HIF-1 levels to the growth of HPV positive lesions? For the past 17 years, a major focus of the Midwest Sexually Transmitted Infections Cooperative Research Center (STI CRC) has been HPV infections. This proposal, along with Dr. Greg Zimet's project, focus on questions associated with HPV infections in the genital tract. While Dr. Zimet's project focuses on prevention, our proposal seeks to identify the mechanisms that regulate the pathogenesis of HPV infections, a major goal of the RFA. I anticipate our work can identify new targets for antiviral therapies to treat existing lesions as well as elucidate potential new biomarkers for HPV-induced disease. Although our project is not directly related to the central theme of the Midwest STI CRC, which is STIs in young men, these studies will utilize clinical materials obtained by the Midwest STI CRC Clinical Core to demonstrate that changes observed in tissue culture models are also detected in primary biopsy material as well as examine new potential new biomarkers. Thus, the project is well integrated into the overall structure of the Midwest STI CRC.