| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
In a previous investigation, we developed a highly reproducible carcinogenesis model by combining DMBA application with physical wounding of the hamster lingual mucosa. Histologically, these lesions showed pathognomonic changes indicative of papillomavirus infection, such as koilocytosis of dysplastic cells, and the nuclei of some dysplastic or cancerous cells were positive for papillomavirus genus-specific antigen (GSA). Furthermore, viral particles resembling papillomavirus, whose 0size was 50-55 nm in diameter, have been detected in the nuclei of these cells.
Using this animal model, we demonstrated the presence of a novel hamster papillomavirus by the molecular cloning and sequencing of this viral genome. The genome was confirmed by complete sequence analysis to be a novel papillomavirus which we designated the hamster oral papillomavirus (HOPV). Moreover, we detected HOPV in the nuclei of dysplastic and malignant lesions in hamster lingual epithelium using in situ hybridization. Computer-assisted phylogenetic analysis of HOPV showed a differing homology with other papillomaviruses in different regions of the genomes. The complete nucleotide sequence of this viral genome consists of 7647bp with a G+C content of 46.6%. This size is similar to that of MnPV (7687bp). This genome has open reading frames (ORFs) on one strand showing the usual order : ORFs E6, E7, E1, E2, L2 and L1. ORF E2 contains the small ORF E4. ORF E5 is missing. These cloned genomes are different from those of other rodent papillomaviruses, such as MmPV and MnPV, and also from previously sequenced animal and human papillomavirus genomes.
Therefore, HOPV infection seems to be a good model for the study on mucosal carcinogenesis associated with papillomavirus and for studies on vaccine prophylaxis and the prevention or treatment of malignant conversion.
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