Highly Efficient Site-Directed RNA Cleavage by Imidazole-Containing Conjugates of Antisense Oligonucleotides

A method has been suggested for the synthesis of conjugates of oligodeoxyribonucleotides with chemical constructs mimicking the ribonuclease A active center for directed fragmentation of RNA. The method is based on sequential addition of a linker group, 9-(methylamino)anthracene, to the 5"- or 3"-terminal phosphate of oligonucleotide, and then an imidazole-containing construct by cycloaddition. The conjugates of oligonucleotides complementary to regions 44–61 (2B–R) and 60–76 (1C–R) of yeast phenylalanine tRNA proved able to cleave tRNA^Phe under physiological conditions preferentially at the sole phosphodiester bond (C63–A64 for 2B–R and C56–G57 for 1C–R, respectively). The half-time of tRNA^Phe hydrolysis in the presence of 2B–R conjugate was 30 min at a 2B–R concentration of 10 M and several minutes at conjugate concentration of 50 M.