T antigen binds to simian virus 40 DNA at the origin of replication.

作者：Steven I. Reed, J Ferguson, Ronald W. Davis, George Robert Stark · 发表于：Proceedings of the National Academy of Sciences · 年份：1975 · DOI：10.1073/pnas.72.4.1605 · 被引用次数：163 · 研究领域：Bacteriophages and microbial interactions、RNA and protein synthesis mechanisms、Polyomavirus and related diseases

A technique employing ferritin-conjugated antibody has been developed to visualize specific protein-DNA complexes in the electron microscope and has been used to demonstrate the preferential binding of simian virus 40 (SV40) T antigen at or near the origin of replication of SV40 DNA, 0.67 fractional length clockwise from the EcoRI restriction endonuclease cleavage site. urified covalently closed supercoiled circles of SV40DNA were treated with partially purified T antigen and the complex was stabilized by crosslinking with glutaraldehyde. Hamster antiT antigen gamma-globulin, ferritin-labeled goat anti-hamster gamma-globulin, and glutaraldehyde were then added sequentially. The location of the bound ferritin cores was measured with respect to the EcoRI cleavage site and the orientation of the cores relative to the ends of the DNA was determined with respect to the locations of Escherichia coli DNA unwinding protein, which binds to covalently closed supercoiled SV40 DNA at either of two preferred sites, 0.46 or 0.90 fractional length clockwide from the EcoRI cleavage site.