title: Identification and biochemical analysis of DNA replication-defective large T antigens from SV40-transformed cells.
abstract: Nine commonly studied Simian virus 40 (SV40)-transformed rodent cell lines were screened for tumor (T) antigens defective in SV40 DNA replication using a simple polyethylene glycol-mediated cell fusion assay. Each line contained a functional origin of SV40 DNA replication, as shown by fusion with Cos 1 cells. Fusion with uninfected monkey cells revealed that T antigens from two lines lacked detectable replicative activity, while T antigens from five other lines exhibited only very weak replicative activity. One line, and a tumor cell line derived from it, expressed T antigen with wild-type replication activity. Biochemical analysis of these proteins revealed defects in DNA binding activity and ATPase activity. One line expressed large T antigen defective in both activities. All of the lines contained complexes of T antigen with the cellular protein p53 and all of the T antigens exhibited nucleotide-binding activity. The results indicate that some of these lines may constitute a useful source of new replication-defective T antigens.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000957:Antigens, Viral, Tumor; D001483:Base Sequence; D002459:Cell Fusion; D002460:Cell Line; D002472:Cell Transformation, Viral; D004261:DNA Replication; D004279:DNA, Viral / Q000378:metabolism; D000882:Haplorhini; D011506:Proteins / Q000378:metabolism; D013539:Simian virus 40 / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D014779:Virus Replication
chemical_list: D000957:Antigens, Viral, Tumor; D004279:DNA, Viral; D011506:Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases