title: Association of simian virus 40 T antigen with replicating nucleoprotein complexes of simian virus 40.
abstract: An immunoprecipitation assay was established for simian virus 40 T-antigen-bound nucleoprotein complexes by means of precipitation with sera from hamsters bearing simian virus 40-induced tumors. About 80% of simian virus 40 replicating nucleoprotein complexes in various stages of replication were immunoprecipitated. In contrast, less than 21% of mature nucleoprotein complexes were immunoprecipitated. Pulse-chase experiments showed that T antigen was lost from most of the nucleoprotein complexes concurrently with completion of DNA replication. T antigen induced by dl-940, a mutant with a deletion in the region coding for small T antigen, was also associated with most of the replicating nucleoprotein complexes. Once bound with replicating nucleoprotein complexes at the permissive temperature, thermolabile T antigen induced by tsA900 remained associated with the complexes during elongation of the replicating DNA chain at the restrictive temperature. These results suggest that simian virus 40 T antigen (probably large T antigen) associates with nucleoprotein complexes at or before initiation of DNA replication and that the majority of the T antigen dissociates from the nucleoprotein complexes simultaneously with completion of DNA replication.
mesh_terms: D000951:Antigens, Neoplasm / Q000276:immunology* / Q000378:metabolism; D000956:Antigens, Viral / Q000276:immunology* / Q000378:metabolism; D000957:Antigens, Viral, Tumor; D002499:Centrifugation, Density Gradient; D003852:Deoxyribonucleoproteins / Q000032:analysis* / Q000378:metabolism; D009154:Mutation; D009698:Nucleoproteins / Q000032:analysis*; D011233:Precipitin Tests; D013539:Simian virus 40 / Q000276:immunology*; D013696:Temperature; D014779:Virus Replication
chemical_list: D000951:Antigens, Neoplasm; D000956:Antigens, Viral; D000957:Antigens, Viral, Tumor; D003852:Deoxyribonucleoproteins; D009698:Nucleoproteins