title: ATP-dependent formation of a specialized nucleoprotein structure by simian virus 40 (SV40) large tumor antigen at the SV40 replication origin.
abstract: The large tumor antigen (T antigen) specified by simian virus 40 (SV40) is required for viral DNA replication. To carry out its function, T antigen binds to duplex DNA at the origin of replication (oriSV40) and exerts a helicase activity that unwinds the two DNA strands. Previous work has defined two binding sites for T antigen near oriSV40, designated sites I and II; site II is within the 64-base-pair core sequence absolutely required for viral DNA replication. We have used electron microscopy and gel electrophoresis to characterize the interaction of T antigen with the origin region. We have found that effective binding to site II under conditions that support DNA replication requires ATP or a nonhydrolyzable analog. In the absence of ATP, T antigen binds mainly to site I; in the presence of ATP, both sites I and II are occupied, and binding is markedly increased. The ATP-dependent reaction generates a complex multimeric structure for T antigen. We conclude that T antigen forms an ATP-dependent nucleoprotein structure at oriSV40. We suggest that this nucleoprotein complex provides for the precise initiation of SV40 DNA replication.
authors.affiliation: Memorial Sloan-Kettering Cancer Center, Program in Molecular Biology, New York, NY 10021.
authors.forename: F B
authors.initials: FB
authors.lastname: Dean
authors.forename: M
authors.initials: M
authors.lastname: Dodson
authors.forename: H
authors.initials: H
authors.lastname: Echols
authors.forename: J
authors.initials: J
authors.lastname: Hurwitz
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000957:Antigens, Viral, Tumor / Q000378:metabolism*; D001665:Binding Sites; D004261:DNA Replication; D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D008854:Microscopy, Electron; D009698:Nucleoproteins / Q000378:metabolism*; D013539:Simian virus 40 / Q000235:genetics*; D014779:Virus Replication
chemical_list: D000957:Antigens, Viral, Tumor; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D009698:Nucleoproteins; D000255:Adenosine Triphosphate