Human papillomavirus type 16 (HPV-16) is the commonest cause of cervical cancer worldwide, yet until recently little was known of the mechanism of action of this leading cause of female disease and death. We have shown that three genes of HPV-16, E6, E7, and E5 are involved in the immortalization and transformation of mammalian cells and this proposal wishes to determine the mechanism of action of E7 and E5. E7 has been shown to bind to the retinoblastoma family of proteins, pRB, p107, and p130, which are involved in cell cycle control during G1. We have shown that E7 also binds to the AP-1 family of transcription factors, and inhibits the DNA binding of c-Jun, a member of the family. AP-1 factors have an important role in the differentiation of human keratinocytes, and family members can form homo- and hetero-dimers, affording them a range of binding and transcriptional activities. It is noteworthy that HPV-16 inhibits keratinocyte differentiation, both in vivo and in vitro and this may partly be explained by E7/Jun interactions. We plan to investigate the effect of E7 on transcription of the various AP-1 family members and how this changes with keratinocyte differentiation. We found that c-Jun also binds to pRB, so we will investigate the functional significance of this complex and determine how E7 effects the interaction. We have shown that HPV-l6 E5 acts with E6 and E7 to optimism keratinocyte immortalization. One mechanism of action is its ability to inhibit degradation and down- regulation of the epidermal growth factor receptor (EGFR), resulting in a strong mitogenic signal. This signal is augmented by the fact that E5 also causes an increase in phosphorylation of the EGFR. The inhibition of degradation is due to a delay in acidification of EGFR containing endosomes through the binding of E5 to the vacuolar ATPase. We wish to carry out, for the first time, a mutagenesis study of E5 to determine functional domains, investigate the mechanism of increased receptor phosphorylation, and determine the effect of E5 on other tyrosine kinase receptors. E5 also effects secretory pathways, and we found that E5 causes instability of the TAP-1 protein, which transports immune peptides to class I molecules as part of the process for the immune recognition of foreign antigens. This results in a down-regulation of the class I molecules on the cell surface, and an increased chance that infected cells will not be recognized by the immune response cells. This could be one reason why HPV lesions persist, and in part may explain the malignant potential of these viruses. We will investigate the mechanism by which E5 increases the instability of the TAP-1 protein, and whether E5 binds directly to TAP-1 proteins.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI030798-10
Application #
2886685
Study Section
Experimental Virology Study Section (EVR)
Program Officer
Hitchcock, Penelope
Project Start
1990-07-01
Project End
2000-12-31
Budget Start
1999-05-01
Budget End
2000-12-31
Support Year
10
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Rochester
Department
Microbiology/Immun/Virology
Type
Schools of Dentistry
DUNS #
208469486
City
Rochester
State
NY
Country
United States
Zip Code
14627
McDade, Simon S; Patel, Daksha; McCance, Dennis J (2011) p63 maintains keratinocyte proliferative capacity through regulation of Skp2-p130 levels. J Cell Sci 124:1635-43
Menges, C W; McCance, D J (2008) Constitutive activation of the Raf-MAPK pathway causes negative feedback inhibition of Ras-PI3K-AKT and cellular arrest through the EphA2 receptor. Oncogene 27:2934-40
Thrash, Barry R; Menges, Craig W; Pierce, Robert H et al. (2006) AKT1 provides an essential survival signal required for differentiation and stratification of primary human keratinocytes. J Biol Chem 281:12155-62
Guess, Jennifer C; McCance, Dennis J (2005) Decreased migration of Langerhans precursor-like cells in response to human keratinocytes expressing human papillomavirus type 16 E6/E7 is related to reduced macrophage inflammatory protein-3alpha production. J Virol 79:14852-62
Westbrook, Thomas F; Nguyen, Don X; Thrash, Barry R et al. (2002) E7 abolishes raf-induced arrest via mislocalization of p21(Cip1). Mol Cell Biol 22:7041-52
Briggs, M W; Adam, J L; McCance, D J (2001) The human papillomavirus type 16 E5 protein alters vacuolar H(+)-ATPase function and stability in Saccharomyces cerevisiae. Virology 280:169-75
Adam, J L; Briggs, M W; McCance, D J (2000) A mutagenic analysis of the E5 protein of human papillomavirus type 16 reveals that E5 binding to the vacuolar H+-ATPase is not sufficient for biological activity, using mammalian and yeast expression systems. Virology 272:315-25
Stoppler, M C; Straight, S W; Tsao, G et al. (1996) The E5 gene of HPV-16 enhances keratinocyte immortalization by full-length DNA. Virology 223:251-4
Antinore, M J; Birrer, M J; Patel, D et al. (1996) The human papillomavirus type 16 E7 gene product interacts with and trans-activates the AP1 family of transcription factors. EMBO J 15:1950-60
Sun, Y N; Lu, J Z; McCance, D J (1996) Mapping of HPV-11 E1 binding site and determination of other important cis elements for replication of the origin. Virology 216:219-22

Showing the most recent 10 out of 15 publications