Figure 9.

Strand invasion-based methodologies for targeting of G4-forming sequences. (A) Use of PPG–PNA to invade the BCL-2 proto-oncogene and avoid the formation of PNA intramolecular quadruplexes (146). (B) Targeting of pre-miR-92b by blocking the C-rich portion of the pre-miR hairpin (149). (C) Inducing G4 formation in plasmid DNA, using two different probes for a) opening the target dsDNA (triplex-forming PNAs, in green) and b) forming a stable duplex with the C-rich strand (Central-binding PNAs, in red) (150).