Figure 3
Characterization of quadruplex formation in single-stranded WT, Mut-A and Mut-E DNAs. (A) WT DNA, Mut-A with mutations in tract A, and Mut-E with mutations in tract E were subjected to annealing in the presence of LiCl, KCl or KCl plus PEG200, followed by DMS footprinting; the cleavage bands were resolved on denaturing PAGE gels. The base sequences are listed at the left of each gel. Vertical lines indicate the cleavage of G-tracts, the * symbols indicate protected guanines involved in G4 formation. M indicates a marker derived from DMS footprinting without ions. (B) Single-stranded template WT, Mut-A, Mut-E and Mut DNAs were annealed with 5′-FAM-labelled primers in the presence of LiCl, KCl or KCl plus PEG200. After the Taq polymerase stop assay, the extension products were separated on denaturing PAGE gels containing 7 M urea. P and FL indicate the lanes containing primers and the full-length product, respectively. The stop products were labelled with * and §, respectively. M indicates the synthesized 35-nt and 45-nt oligonucleotides serving as markers. The G-core sequences are listed below the gel and the stop sites are indicated with arrows.
