| abstract |
A triplex forming oligonucleotide is complementary pursuant to the G/T or A/G recognition motif to a homopurine, or substantially homopurine target sequence in double stranded nucleic acids, and at least one and preferably all of the guanine bases are replaced by their pyrazolo[3,4-d]pyrimidine analog, namely by 6-amino-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one. The oliginucleotides containing the pyrazolo[3,4-d]pyrimidine analog of guanine exhibit a lesser degree of self-association, and lack the nucleophilic nitrogen atom in the 7 position of guanine. The latter feature results in a diminished extent of self-cross-linking in ODNs which also have a covalently attached cross-linking agent. |