Figure 6.

Taq polymerase stop assay on control G4-forming templates devoid of the PNA complementary sequence. (A) LTR-III+IV, b-raf, bcl-2 and c-myc templates were amplified by Taq polymerase at 60°C in the absence (lanes 5, 9, 13 and 17) and presence of 1 × 10⁻¹ M KCl, alone (lanes 6, 10, 14 and 18) or with 4 × 10⁻⁷ M of NDI-PNA 6 (lanes 7, 11, 15 and 19) or NDI 6 (lanes 8, 12, 16 and 20). A template (non-G4 cnt) made of a scrambled sequence unable to fold into G4 was also used as internal control (lanes 1–4). Lane P: unreacted labeled primer. Lane M: ladder of markers obtained by the Maxam and Gilbert sequencing carried out on the amplified strand complementary to the template strand. Vertical bars indicate G4-specific Taq polymerase stop sites. * indicates the stop site corresponding to the binding of the PNA moiety to its complementary sequence on the LTR-III+IV template. (B) Quantification of lanes 5–8 shown in panel A. Quantification of stop bands corresponding to LTR-III, LTR-IV G4s and of the full-length amplification product (FL) is shown. (C) Quantification of lanes 9–12 shown in panel A. Quantification of stop bands corresponding to b-raf G4 and of the full-length amplification product (FL) is shown. (D) Quantification of lanes 13–16 shown in panel A. Quantification of stop bands corresponding to bcl-2 G4 and of the full-length amplification product (FL) is shown. (E) Quantification of lanes 17–20 shown in panel A. Quantification of stop bands corresponding to c-myc G4 and of the full-length amplification product (FL) is shown.