Assembly of T-Antigen Double Hexamers on the Simian Virus 40 Core Origin Requires Only a Subset of the Available Binding Sites
AUTOR(ES)
Joo, Woo S.
FONTE
American Society for Microbiology
RESUMO
Initiation of simian virus 40 (SV40) DNA replication is dependent upon the assembly of two T-antigen (T-ag) hexamers on the SV40 core origin. To further define the oligomerization mechanism, the pentanucleotide requirements for T-ag assembly were investigated. Here, we demonstrate that individual pentanucleotides support hexamer formation, while particular pairs of pentanucleotides suffice for the assembly of T-ag double hexamers. Related studies demonstrate that T-ag double hexamers formed on “active pairs” of pentanucleotides catalyze a set of previously described structural distortions within the core origin. For the four-pentanucleotide-containing wild-type SV40 core origin, footprinting experiments indicate that T-ag double hexamers prefer to bind to pentanucleotides 1 and 3. Collectively, these experiments demonstrate that only two of the four pentanucleotides in the core origin are necessary for T-ag assembly and the induction of structural changes in the core origin. Since all four pentanucleotides in the wild-type origin are necessary for extensive DNA unwinding, we concluded that the second pair of pentanucleotides is required at a step subsequent to the initial assembly process.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=110647Documentos Relacionados
- Large T-Antigen Double Hexamers Imaged at the Simian Virus 40 Origin of Replication
- Cooperative assembly of simian virus 40 T-antigen hexamers on functional halves of the replication origin.
- Dimerization of simian virus 40 T-antigen hexamers activates T-antigen DNA helicase activity.
- The Simian Virus 40 Core Origin Contains Two Separate Sequence Modules That Support T-Antigen Double-Hexamer Assembly
- Sequence Requirements for the Assembly of Simian Virus 40 T Antigen and the T-Antigen Origin Binding Domain on the Viral Core Origin of Replication