Specific hybridization arrest of dihydrofolate reductase mRNA in vitro using anti-sense RNA or anti-sense oligonucleotides.

Three anti-sense RNAs and ten synthetic anti-sense oligonucleotides were tested for their ability specifically to arrest translation of human dihydrofolate reductase (DHFR) mRNA in a nuclease-treated rabbit reticulocyte lysate. Quantitative hybrid arrest of DHFR mRNA by anti-sense RNA required that the RNA hybridize to the 5' end of DHFR mRNA. Oligonucleotides of length 11-20, complementary to various sites near the 5' end of DHFR mRNA, also could cause specific inhibition of DHFR mRNA translation. Oligonucleotide length and concentration were shown to be important variables in hybrid arrest of DHFR mRNA. Neither the exact oligonucleotide binding site position near the 5' end of the mRNA nor prehybridization conditions were important variables. The combination of short oligonucleotides with contiguous binding sites was shown to synergize their ability to inhibit specifically DHFR mRNA translation.