title: Complex of simian virus 40 large tumor antigen and 48,000-dalton host tumor antigen.
abstract: Simian virus 40 large tumor antigen (T Ag) can be separated by sucrose gradient sedimentation into a rapidly sedimenting, maximally phosphorylated fraction and a slowly sedimenting, less phosphorylated fraction. The Mr 48,000 host tumor antigen (48,000 HTA, also called nonviral T Ag) is preferentially complexed with the maximally phosphorylated T Ag. Pulse-labeled T Ag sediments as a 5-6S monomer, whereas T Ag radiolabeled for progressively longer periods slowly increases in sedimentation coefficient to give a broad distribution between 5 S and greater than 28 S. Mutation in the viral A locus causes a decrease in T Ag phosphorylation and a marked decrease in 48,000 HTA binding, shifting the sedimentation coefficient of T Ag to the monomer value. The more highly phosphorylated T Ag also has the highest affinity for chromatin.
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000302:isolation & purification*; D000956:Antigens, Viral / Q000302:isolation & purification*; D000957:Antigens, Viral, Tumor; D002499:Centrifugation, Density Gradient; D002843:Chromatin / Q000378:metabolism; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D009154:Mutation; D010766:Phosphorylation; D010768:Phosphoserine / Q000032:analysis; D010769:Phosphothreonine / Q000032:analysis
chemical_list: D000951:Antigens, Neoplasm; D000956:Antigens, Viral; D000957:Antigens, Viral, Tumor; D002843:Chromatin; D010769:Phosphothreonine; D010768:Phosphoserine