title: Levels of bovine papillomavirus RNA and protein expression correlate with variations in the tumorigenic phenotype of hamster cells.
abstract: Three independent cell lines were established from primary cultures of LSH hamster embryo cells infected with bovine papillomavirus type 1 (BPV-1). Although these cell lines differed in their in vitro saturation densities, none was capable of colony formation in soft agar. Interestingly, two cell lines (BPV-HE1 and BPV-HE3) were tumorigenic in nude mice, syngeneic hamsters, and allogeneic hamsters, whereas BPV-HE2 was not. All three cell lines contained similar numbers of the BPV-1 genome (approximately 50 to 200 copies per cell). However, the nontumorigenic BPV-HE2 cell line contained very low levels of BPV-specific RNA and only small amounts of the BPV-1 E5 transforming protein. The efficiency and rate of tumor formation by BPV-HE1 and BPV-HE3 correlated directly with the apparent amount of viral E5 protein. This analysis suggests that there is a threshold level of BPV protein synthesis required for tumorigenicity, there is a continuum of tumorigenic phenotypes which may depend upon the level of BPV protein expression, and BPV-transformed hamster cells can withstand allogeneic transplantation.
mesh_terms: D000818:Animals; D000952:Antigens, Polyomavirus Transforming; D000957:Antigens, Viral, Tumor / Q000032:analysis / Q000096:biosynthesis*; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D006224:Cricetinae; D004279:DNA, Viral / Q000032:analysis; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000209:etiology; D009856:Oncogene Proteins, Viral / Q000032:analysis / Q000096:biosynthesis*; D027383:Papillomaviridae / Q000235:genetics / Q000472:pathogenicity*; D010641:Phenotype; D012367:RNA, Viral / Q000032:analysis / Q000096:biosynthesis*
chemical_list: D000952:Antigens, Polyomavirus Transforming; D000957:Antigens, Viral, Tumor; D004279:DNA, Viral; D009856:Oncogene Proteins, Viral; D012367:RNA, Viral