title: Malignant transformation of rat cells by the polyomavirus middle T gene.
abstract: To gain an insight into the molecular mechanism of cooperation between the polyomavirus middle T gene and cellular genes in the tumorigenic process, we have examined various properties of rat cell lines transformed by middle T alone. Middle T transformants display a phenotype ranging from nontumorigenic (flat) to fully transformed (tumorigenic) and the phenotype of a given cell line correlates very well with its cellular level of middle T antigen. Highly transformed, tumorigenic variants arise spontaneously in the flat cells during their growth with a mutation rate of 2.2 X 10(-5) per cell per generation. These variants contain elevated levels of both middle T antigen and middle T transcripts, suggesting that fully transformed cells arise as a consequence of an efficient mode of viral gene expression.
mesh_terms: D000818:Animals; D000952:Antigens, Polyomavirus Transforming; D000957:Antigens, Viral, Tumor / Q000096:biosynthesis / Q000235:genetics*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D005814:Genes, Viral; D009154:Mutation; D009856:Oncogene Proteins, Viral / Q000096:biosynthesis / Q000235:genetics*; D010641:Phenotype; D011120:Polyomavirus / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D051381:Rats; D014158:Transcription, Genetic
chemical_list: D000952:Antigens, Polyomavirus Transforming; D000957:Antigens, Viral, Tumor; D009856:Oncogene Proteins, Viral