An Enhanced Epithelial Response of a Papillomavirus Promoter to Transcriptional Activators

Abstract

Mucosal epitheliotropic papillomaviruses have a similar long control region (LCR) organization: a promoter region, an enhancer region, and a highly conserved distribution of E2 DNA binding sites. The enhancer of these viruses is epithelial-specific, as it fails to activate transcription from heterologous promoters in nonepithelial cell types (Gloss, B., Bernard, H. U., Seedorf, K., and Klock, G.

Quercetin elevates p27Kip1 and arrests both primary and HPV16 E6/E7 transformed human keratinocytes in G1

“…Higher quercetin concentrations did not result in further increase of p27 Kip1 promoter activity (data not shown). The pGL3TK plasmid in which the tk promoter directs expression of luciferase (Vance et al, 1999) was used as a control to examine whether any possible effect observed was specific for the p27…”

The Fidelity of HPV16 E1/E2-mediated DNA Replication

“…The E2 protein forms homodimers and recognizes and binds to 12bp palindromic DNA sequences in the transcriptional control region of HPV (4). E2 can then regulate transcription from the adjacent promoter that controls the expression of the HPV oncogenes E6 and E7; E2 can either activate or repress transcription depending upon E2 protein levels and the cell type (5,6). As well as regulating transcription E2 is also essential for replication of the viral genome; there are three E2 DNA binding sequences surrounding the viral origin (ori) of replication and a physical interaction between E2 and E1 results in recruitment of E1 to the ori sequence (7,8,9).…”

A Novel Silencer Element in the Bovine Papillomavirus Type 4 Promoter Represses the Transcriptional Response to Papillomavirus E2 Protein

“…Construction of the PV2 6E2 and tk 6E2 reporter constructs has been described previously (39). The lcr/tk hybrid promoter was generated by splicing-by-overlap-extension PCR.…”

“…This epithelial preference is not extended to heterologous promoters such as the thymidine kinase (tk) promoter. This was the first time that a level of epithelial specificity has been shown to reside in a papillomavirus promoter region (39).…”

“…PalK cells are the natural target cell type for transformation by BPV-4. Insertion of multiple E2 sites upstream of the BPV-4 promoter demonstrated that the BPV-4 epithelial cell-specific enhancer is not required for the enhanced activity of E2 in epithelial cells (39). The BPV-4 promoter region itself shows an enhanced epithelial response to activation, not only by E2 but also by several other transcriptional activators.…”