title: Fluctuation of simian virus 40 (SV40) super T-antigen expression in tumors induced by SV40-transformed mouse mammary epithelial cells.
abstract: Higher-molecular-weight forms of the simian virus 40 (SV40) large tumor antigen (T-Ag), designated super T-Ag, are commonly found in SV40-transformed rodent cells. We examined the potential role of super T-Ag in neoplastic progression by using a series of clonal SV40-transformed mouse mammary epithelial cell lines. We confirmed an association between the presence of super T-Ag and cellular anchorage-independent growth in methylcellulose. However, tumorigenicity in nude mice did not correlate with the expression of super T-Ag. In the tumors that developed in nude mice, super T-Ag expression fluctuated almost randomly. Cell surface iodination showed that super T-Ag molecules were transported to the epithelial cell surface. The biological functions of super T-Ag remain obscure, but it is clear that it is not important for tumorigenicity by SV40-transformed mouse mammary epithelial cells. Super T-Ag may be most important as a marker of genomic rearrangements by the resident viral genes in transformed cells.
mesh_terms: D000818:Animals; D000952:Antigens, Polyomavirus Transforming; D000957:Antigens, Viral, Tumor; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D002999:Clone Cells; D008321:Mammary Glands, Animal; D051379:Mice; D009374:Neoplasms, Experimental / Q000276:immunology* / Q000382:microbiology; D009856:Oncogene Proteins, Viral; D013539:Simian virus 40 / Q000276:immunology*
chemical_list: D000952:Antigens, Polyomavirus Transforming; D000957:Antigens, Viral, Tumor; D009856:Oncogene Proteins, Viral