HPV oncoproteins

Expression of viral tumor promoter genes Enhanced expression of Epstein-Barr early antigen Ohmori et al. [103] Upregulation of HPV oncoproteins by a variety of cytokines Lembo et al. [104]... 

Human papilloma virus (HPV) type 16 oncoprotein E7 Potato virus X in tobacco leaf (complete reading frame) Immunogenic in mice when administered parenterally. Mice protected moderately when challenged with surrogate (C3 cells). 100... 

Fig. 2.17. Degradation of the tumor suppressor protein p53 by the ubiquitin-proteosome system. The oncoprotein E6 of the human papilloma virus (HPV) forms a specific complex with the p53 protein and can thus induce the degradation of p53. The E6-p53 complex is recognized by E6-AP, a E3 enzyme of the ubiquitin pathway, as a target protein, whereby a ubiquitin residue is transferred to a lysine residue of p53. In this process, the E6 protein serves as the recognition element for ubiquitin hgation of p53.

DNA viruses that can trigger tumors are found in the classes of the polyomaviruses, the adenoviruses and the papUloma viruses. The polyoma viruses with the SV40 virus as a well studied representative, adenoma virus and human papUloma virus (HPV) are associated with formation of tumors in humans and have genes coding for proteins with the properties of oncoproteins. The oncoproteins of aU three viruses interfere with the pRb function by Ufting its inhibition of transcription factor E2F. It is assumed that the tumor-promoting activity of the proteins is due, in particular, to this property. 

HPV-16 encodes a set of early gene oncoproteins (E6 and E7) responsible for cellular immortalization. HPV types 16 and 18 E6 and E7 proteins are known to interact strongly with p53 and retinoblastoma (Rb) tumor suppressor gene products, respectively (2). The association of E6 with p53 marks this tumor suppressor for rapid ubiquitin-mediated proteolysis. Reduced levels of p53 prevent the cell from activating cell cycle arrest and/or induction of apoptosis in genetically mutated cells. 

Quantitatively assessing oncoproteins in HPV-transformed cells is useful for evaluating viral activity and the potential effectiveness of antiviral therapy (4). The following describes immunodetection methods for assaying levels of human papillomavirus E6 and E7 protein in total protein cell lysates. This pro-... 

The HeLa cells originally were transformed by the HPV-encoded oncoproteins (that neutralize p53 and Rb cellular mmor suppressor genes). Distinction between self and non-self probably did not exist when ancient chimeric cells were formed, and engulfed bacteria were accepted as self (proteobacteria for the mitochondrion cyanobacteria for the chloroplast). Malignantly transformed cells appear to be impervious, as to the distinction between self and non-self, when it comes to... 

Gyongyosi E, Szalmas A, Ferenezi A, Konya J, Gergely L, Veress G. Effects of human papillomavirus (HPV) t3q>e 16 oncoproteins on the expression of involucrin in human keratinocytes. Virol J. 2012 9 36. doi 10.1186/1743-422X-9-36. 

Szalmas A, Gyongyosi E, Ferenczi A, Laszlo B, Karosi T, Csomor P, Gergely E, Veress G, Konya J. Activation of Scr, F5m and Yes non-receptor t5nosine kinases in keratinocytes expressing human papillomavims (HPV) type 16 E7 oncoprotein. Virol J. 2013 10 79. doi 10.1186/1743-422X-10-79. 

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