Rap1p⋅DNA⋅Gcr1p ternary complex formation requires DNA-binding sites for both Rap1p and Gcr1p. (A) DNA sequence of oligonucleotide probes, N, +5, and ΔG, used in this study. Rap1p- and Gcr1p-binding sites are shown in boldface type. (B) In vitro DNA-binding reactions were carried out under standard conditions as described in the text. Preparations of Rap1p and Gcr1p were allowed to react with the radiolabeled probe DNAs either separately or together as indicated on the figure. Nucleoprotein complexes (Rap1p⋅DNA⋅Gcr1p, Rap1p⋅DNA, Gcr1p⋅DNA) were resolved from free DNA by nondenaturing polyacrylamide gel electrophoresis and were revealed by autoradiography of the dried gel. Lanes 1–4 utilized oligonucleotide N, a probe with native spacing between Rap1p- and Gcr1p-binding sites; lanes 5–8 utilized oligonucleotide +5, a probe with out-of-phase spacing between Rap1p- and Gcr1p-binding sites; and lanes 9–12 utilized oligonucleotide ΔG, a probe with a Rap1p-binding site but not a Gcr1p-binding site.