In order to enhance the nuclear uptake of triple-helix forming oligonucleotides (TFOs), a triglycylcholesterol group was attached to the 3' end. The peptide unit was introduced as a "labile" linker with the aim of releasing the oligonucleotide from the endosomes by the action of peptidases after crossing the cell membrane. Cholesteryl-CPG (8) and -TentaGel (9) supports containing 2-[N-(glycylglycylglycyl)amino]propane-1,3-diol (GAP-3) linker were prepared and used for automated oligonucleotide synthesis. The synthesis, characterization, and stability of these compounds are described.