Peptide nucleic acids: Cellular delivery and recognition of DNA and RNA targets

Peptide nucleic acids (PNAs) can be conveniently delivered into cells in complex with DNA and cationic lipid. This advance enables researchers to test the hypothesis that PNAs offer advantages for recognition of DNA or RNA targets within cells. In this review, I describe the intracellular delivery of PNAs as DNA-PNA-cationic lipid complexes and discuss recognition of three classes of nucleic acid target: duplex DNA, single-stranded mRNA, and the ribonucleoprotein telomerase. These targets differ dramatically in their potential for base-paired structure, offering distinct challenges for hybridization by PNAs. It is apparent that PNAs can exert sequence-specific effects within cells, and their full potential has only begun to be explored.