Stoichiometry and mechanism of assembly of SV40 T antigen complexes with the viral origin of DNA replication and DNA polymerase alpha-primase

Fluorescent 3'(2')-O-(2,4,6-trinitrophenyl)adenine nucleotide analogues were used as specific probes in the determination of the stoichiometry and mechanism of assembly of the interaction between the large tumor antigen, T, of simian virus 40 and the DNA carrying the origin of viral replication. Results reveal that a double hexamer of the T antigen assembles on the viral origin of replication via successive addition of monomers. Further, T hexamers are able to bind directly to DNA polymerase alpha-primase.