title: Reinitiated expression of EJras transgene in targeted epidermal cells of transgenic rabbits by cottontail rabbit papillomavirus infection.
abstract: Transgenic rabbits carrying the EJras oncogene have been established in our laboratory (Am. J. Pathol. 155 (1999) 315). The expression of the ras gene is targeted to the epidermal keratinocytes using the upstream regulatory region (URR) of the cottontail rabbit papillomavirus (CRPV). All of the transgenic rabbits develop keratoacanthomas at multiple sites in the skin at 2-3 days after birth, and the tumors spontaneously regress in 1.5-2 months. With regression of the keratoacanthomas, the rabbits appear normal and EJras expression is undetectable in their skin. To determine if CRPV infection would reinitiate the expression of the EJras transgene and make the rabbits more sensitive to tumorigenesis, the rabbits were infected with CRPV at 2 months of age when the keratoacanthomas had regressed. This study shows that CRPV infection of the transgenic rabbit skin could shorten the latency required for CRPV papilloma initiation, and significantly increase the tumor growth and persistence rate compared with non-transgenic rabbits. Furthermore, EJras expression became detectable in the CRPV induced papillomas in transgenic rabbits, but not in the papillomas of non-transgenic rabbits. These results indicate that CRPV infection is able to reinitiate the expression of the CRPV URR controlled EJras oncogene carried by the transgenic rabbits and that the expression of EJras can enhance the tumorigenesis of CRPV infection.
authors.affiliation: Department of Comparative Medicine, H054, The Pennsylvania State University College of Medicine, P.O. Box 850, Hershey, PA 17033, USA. xxp1@psu.edu
authors.forename: X
authors.initials: X
authors.lastname: Peng
authors.forename: J W
authors.initials: JW
authors.lastname: Griffith
authors.forename: C M
authors.initials: CM
authors.lastname: Lang
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D003043:Cocarcinogenesis; D012777:Cottontail rabbit papillomavirus; D004817:Epidermis / Q000502:physiology*; D005260:Female; D015967:Gene Expression Regulation, Viral / Q000235:genetics; D011905:Genes, ras / Q000235:genetics; D020022:Genetic Predisposition to Disease; D007636:Keratoacanthoma / Q000235:genetics / Q000821:virology; D015513:Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics*; D030361:Papillomavirus Infections / Q000235:genetics* / Q000821:virology; D011817:Rabbits; D012878:Skin Neoplasms / Q000235:genetics* / Q000821:virology*
chemical_list: D015513:Oncogene Proteins; C077183:human oncogene protein EJ-ras