ANTISENSE SEQUENCE-DIRECTED CROSS-LINKING OF RNA OLIGONUCLEOTIDES BY MITOMYCIN

Conjugates of mitomycin C (MC) and 15-mer oligodeoxyribonucleotides (O DNs) were synthesized in which the 7-amino group of MC was tethered by either a (-CH2-)(6) or a (-CH2-)(12) linker to the 5'-terminal phosph ate of the ODNs. The conjugates were shown to be cross-linked selectiv ely to complementary 18-mer oligoribonucleotides (ORNs). The cross-lin king was dependent on reductive activation of the MC moiety of the con jugates by NADPH-cytochrome c reductase/NADPH. The cross-linked ODN-OR N hybrid duplexes were characterized as such by degeneration by RNase H. Cross-linking efficiencies of the conjugates were 50 and 25% in the case of the (-CH2-)(12) tether and the (-CH2-)(6) tether respectively . The results demonstrate the feasibility of sequence-targeted alkylat ion of RNA by MC via antisense recognition.