The E5 oncoprotein of bovine papillomavirus type I is a small, hydrophobic polypeptide localized predominantly in the Golgi complex. E5-mediated transformation is often associated with activation of the PDGF receptor (PDGF-R). However, some E5 mutants fail to induce PDGF-R phosphorylation yet retain transforming activity, suggesting an additional mechanism of action. Since E5 also interacts wit...

The E5 proteins of human papillomaviruses (HPVs) are small hydrophobic proteins that are expressed in the early and late stages of the viral life cycle; however, their role in HPV pathogenesis is not clearly understood. In this study, a split-ubiquitin yeast (Saccharomyces cerevisiae) two-hybrid system was used to identify B-cell-associated protein 31 (Bap31) as a binding partner of HPV E5 prot...

To determine the function of the E5 open reading frame (ORF) of the human papillomaviruses (HPVs), rodent fibroblast cell lines were transfected with the E5 ORF of HPV type 6 (HPV-6) and HPV-16 expressed from an exogenous promoter. Transfected fibroblasts were transformed to colony formation in soft agar, and the transformation frequency was increased by epidermal growth factor (EGF) but not by...

Human papillomavirus (HPV) infection is a prerequisite of developing cervical cancer, approximately half of which are associated with HPV type 16. HPV 16 encodes three oncogenes, E5, E6, and E7, of which E5 is the least studied so far. Its roles in regulating replication and pathogenesis of HPV are not fully understood. Here we utilize high-throughput screening to coordinately investigate the e...

The function of the E5 protein of human papillomaviruses (HPV) is not well characterized, and controversies exist about its role in the viral life cycle. To determine the function of E5 within the life cycle of HPV type 31 (HPV31) we first constructed HPV31 mutant genomes that contained an altered AUG initiation codon or stop codons in E5. Cell lines were established which harbored transfected ...

Bovine papillomaviruses (BPVs) are oncogenic viruses. In cattle, BPV-1/2 is associated with urinary bladder cancer and BPV-4 with upper GI tract cancer. BPV E5 is a small hydrophobic protein localised in the endoplasmic reticulum (ER) and Golgi apparatus (GA). E5 is the major transforming protein of BPVs, capable of inducing cell transformation in cultured mouse fibroblasts and, in cooperation ...

Among high-risk human papillomaviruses (HPV), HPV-16 infection is the most prevalent causative factor for cervical cancer. Beside other mucosal targets, HPV-16 was reported to infect the placenta and to replicate in trophoblastic cells. Since these cells share invasive properties of tumoral cells, they represent an ideal model to investigate several oncogenic processes. In the present work, we ...

We examined expression of the E5 transforming protein of bovine papillomavirus type 1 (BPV-1) in naturally and experimentally infected bovine cells. Bovine conjunctival fibroblasts transformed in vitro by experimental infection with purified BPV-1 virions expressed significantly higher amounts of the 7-kDa E5 protein than BPV-1-transformed murine C127 cells. Indirect immunofluourescence analysi...

Early gene E5 of bovine papillomavirus type 1 encodes a 44-amino-acid protein whose expression can transform immortalized mouse cell lines. We have previously reported that a chemically synthesized E5 peptide functions to induce cellular DNA synthesis upon microinjection into growth-arrested mouse cells. We further defined the two E5 domains essential for the full DNA synthesis induction activi...

We report a highly ordered intercalated hexagonal binary superlattice of hydrophilically functionalized single-walled carbon nanotubes (p-SWNTs) and surfactant (C12 E5 ) cylindrical micelles. When p-SWNTs (with a diameter slightly larger than that of the C12 E5 cylinders) were added to the hexagonally packed C12 E5 cylindrical-micellar system, p-SWNTs positioned themselves in such a way that th...