| Abstract: | Experimental studies of the effects of antisense oligonucleotides on translation of mRNAs in cell-free systems are reviewed. Oligonucleotides complementary to the leader sequences or to the sequence overlapping the initiating codon region of mRNAs inhibit translation of the messengers. In the presence of ribonuclease H, oligodeoxyribonucleotides and their phosphorothioate analogs complementary either to the mentioned mRNA regions or to the mRNA coding sequence suppress the translation due to the RNAs cleavage. This inhibition-enhancing mechanism does not operate in the case of the oligonucleotide analogs--oligonucleoside methylphosphonates and oligonucleotides built of the alpha-nucleosides, since the complexes formed by RNA and these analogs are not substrates of the ribonuclease H. The translation inhibition efficiency is determined by the oligonucleotides lengths and by the availability of the complementary sequence in the mRNA structure. The oligonucleotides inhibitory power can be improved by the coupling to the oligonucleotides of the intercalating groups and the reactive groups. |
