Skip to main content
. Author manuscript; available in PMC: 2016 Jul 8.
Published in final edited form as: Oncogene. 2015 Nov 23;35(25):3217–3226. doi: 10.1038/onc.2015.424

Figure 3. Chemical modifications of oligonucleotide backbones.

Figure 3

Phosphorothioate-modified oligonucleotides (PTO) are formed by creating phosphorothioate bonds through the substitution of a sulfur atom for a non-bridging oxygen in the phosphate backbone. Peptide nucleic acids (PNAs) are DNA analogues with backbones consisting of N-(2-aminoethyl)-glycine units linked by peptide bonds. The addition of a positively charged guanidinium group to the PNA backbone (GPNA) facilitates oligomer uptake across cell membranes.