The E5 Gene of HPV-16 Enhances Keratinocyte Immortalization by Full-Length DNA

Stöppler, Melissa Conrad; Straight, Samuel W.; Tsao, Grace; Schlegel, Richard; McCance, Dennis J.

doi:10.1006/viro.1996.0475

Cited by 102 publications

(65 citation statements)

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Section: Resultsmentioning

confidence: 99%

“…S2, available in JGV Online) thus justifying their use in HPV studies. Additionally, for their studies of HPV-16 E5, other authors have used either non-human cells (Straight et al, 1993;Tsao et al, 1996), or cells previously immortalized by other agents such as HPV-16 E6 and E7 oncogenes or SV40 large T oncogene (Stoppler et al, 1996;Tsao et al, 1996;Krawczyk et al, 2008;Regan & Laimins, 2008).Organotypic three-dimensional raft cultures have been particularly useful in unravelling the impact of HPV genes on the fate of keratinocytes (Chow & Broker, 1997).Here, we have studied the effects of E5 on cell proliferation and differentiation in raft cultures of HaCaT keratinocytes. Efforts have been made to present the same areas of each raft culture for ease of comparison.…”

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confidence: 99%

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Effects of human papillomavirus type 16 E5 deletion mutants on epithelial morphology: functional characterization of each transmembrane domain

Barbaresi

Cortese

Quinn

et al. 2009

Journal of General Virology

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Human papillomavirus type 16 (HPV-16) is the cause of cervical cancer. The HPV genome encodes three transforming proteins, E5, E6 and E7. E6 and E7 are the main transforming proteins of HPV, while the role of E5 is still poorly understood. Using three dimensional organotypic raft cultures we show that HaCaT human keratinocytes expressing HPV-16 E5 form a very perturbed epithelium, with simultaneous hyperkeratinization of some cells and defective differentiation of other cells. The basal layer is disturbed and many cells invade the collagen matrix. Many cells among the differentiated layers show characteristics of basal cells: progression through the cell cycle, expression of cytokeratin 14, lack of cytokeratin 1 and production of matrix metalloproteases (MMP). Using deletion mutants which encompass the three hydrophobic domains of E5, we have assigned the ability to promote invasion of the matrix to the first hydrophobic domain, and the capacity to induce MMP9 to the C-terminal four amino acids. We also show that invasion and production of MMP9 can be dissociated, as mutants that are still capable of invasion do not produce MMP9 and vice versa. INTRODUCTIONHuman papillomaviruses (HPVs) infect mucosal and cutaneous epithelia and induce lesions that can persist and progress to cancer; this is particularly so for HPV-16, the major cause of cervical cancer. The HPV genome encodes three transforming proteins, E5, E6 and E7. E6 and E7 are the main transforming proteins of HPV, while the role of E5 is still poorly understood. While E6 and E7 are expressed throughout the course of the disease and are necessary for the maintenance of a transformed phenotype, E5 is expressed during the early stages of infection and its expression is often, but not always, extinguished as the lesion progresses towards malignancy (Cavuslu et al., 1996;Chang et al., 2001;Kell et al., 1994).E5 of HPV-16 is a hydrophobic membrane-associated protein 83 aa long, with three well-defined hydrophobic regions, believed to be transmembrane domains, and short regions at the N and C termini that may extend beyond the lipid bilayer. E5 is localized in the endomembranes of the infected cells, the Golgi apparatus and the endoplasmic reticulum (Suprynowicz et al., 2006). The functions of E5 appear to be multiple. E5 binds to the 16K subunit c (a component of the proton pump vacuolar ATPase) (Conrad et al., 1994) and reduces acidification of the endomembrane compartments (Schapiro et al., 2000;Straight et al., 1995), resulting in the sustained activation of the receptor for epidermal growth factor (EGF-R) (Straight et al., 1993). Likely through the activation of EGF-R, E5 is also responsible for the activation of other kinases, such as MAP kinase and PI3 kinase (Crusius et al., 1997;Kim et al., 2006). The impeded acidification of the Golgi apparatus and other organelles is likely to be 3These authors contributed equally to this work. , 2005, 2006). In transgenic mice, E5 alters the growth and differentiation of stratified epithelia and induces epithelial t...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Effects of human papillomavirus type 16 E5 deletion mutants on epithelial morphology: functional characterization of each transmembrane domain

Barbaresi

Cortese

Quinn

et al. 2009

Journal of General Virology

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“…In addition, the HPV16 E5 protein cooperates with the HPV16 E7 protein in inducing proliferation of primary rodent cells, and acute expression of the HPV16 E5 protein stimulates cellular DNA synthesis in primary human keratinocytes (Bouvard et al, 1994;Faulkner and Banks, 1995;Straight et al, 1993;Venuti et al, 1998). E5 mutations in full-length HPV16 genomic DNA also inhibit immortalization of keratinocytes, but it is not clear if the E5 protein plays a direct role in immortalization (Stoppler et al, 1996). Transforming activity of additional E5 proteins has been demonstrated in various cell types and assays (Ghai et al, 1996;Rho et al, 1996).…”

Section: Hpv E5 Transforming Proteinsmentioning

confidence: 99%

Mechanisms of cell transformation by papillomavirus E5 proteins

2001

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The papillomavirus E5 proteins are short, hydrophobic transforming proteins. The transmembrane E5 protein encoded by bovine papillomavirus transforms cells by activating the platelet-derived growth factor b receptor tyrosine kinase in a ligand-independent fashion. The bovine papillomavirus E5 protein forms a stable complex with the receptor, thereby inducing receptor dimerization and activation, trans-phosphorylation, and recruitment of cellular signaling proteins to the receptor. The E5 proteins of the human papillomaviruses also appear to a ect the activity of growth factor receptors and their signaling pathways. The interaction of papillomavirus E5 proteins with a subunit of the vacuolar ATPase may also contribute to transformation. Further analysis of these unique mechanisms of viral transformation will yield new insight into the regulation of growth factor receptor activity and cellular signal transduction pathways. Oncogene (2001) 20, 7866 ± 7873.

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“…It is able to transform murine fibroblasts and keratinocytes (Valle and Banks, 1995;Chen et al, 1996). E5 also enhances the immortalization potential of E6 and E7, and stimulates the proliferation of human and mouse primary cells in cooperation with E7 (Bouvard et al, 1994;Sto¨ppler et al, 1996). The E5 protein is known to inhibit gapjunctional intercellular communication (Oelze et al, 1995), which may lead to disturbance of normal epithelial maintenance and differentiation.…”

Section: Introductionmentioning

confidence: 99%

Genes involved in cell adhesion, cell motility and mitogenic signaling are altered due to HPV 16 E5 protein expression

et al. 2007

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We investigated the effects of the human papillomavirus type 16 E5 oncogene on cellular gene expression in human epithelial cells using cDNA microarray. In a genome-wide microarray assay, the expression of 179 genes was found to be significantly altered due to E5 expression. The expression of lamin A/C was downregulated at protein level. The expression of protein kinase C-d and phosphoinositide-3-kinase proteins was found to be upregulated. We also observed increased motility of E5-expressing cells. We conclude that the E5 protein affects several cellular pathways involved in cell adhesion, cell motility and mitogenic signaling. These alterations may together lead to inhibition of apoptosis and facilitate the establishment of persistent infection in the epithelium.

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The E5 Gene of HPV-16 Enhances Keratinocyte Immortalization by Full-Length DNA

Cited by 102 publications

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Effects of human papillomavirus type 16 E5 deletion mutants on epithelial morphology: functional characterization of each transmembrane domain

Effects of human papillomavirus type 16 E5 deletion mutants on epithelial morphology: functional characterization of each transmembrane domain

Mechanisms of cell transformation by papillomavirus E5 proteins

Genes involved in cell adhesion, cell motility and mitogenic signaling are altered due to HPV 16 E5 protein expression

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