α-DNA VI: Comparative study of α- and β-anomeric oligodeoxyribonucleotides in hybridization to mRNA and in cell free translation inhibition

Abstract

α and ß-anomeric d(G2T12G2) oligodeoxyribonucleotides were compared for their hybridization to rA12 : the observed melting temperatures are 27°C for ß-oligodeoxyribonucleotide/RNA hybrid and 53°C for α-oligodeoxyribonucleotide/RNA. α-oligonucleotides with the four bases, complementary to natural mRNAs, were synthesized for the first time, labeled at their 5′-end with [32P] and used as probes in Northern blot experiments. In spite of these higher affinities for their target RNA's, they were unable to block translation of natural or synthetic mRNA's in rabbit reticulocyte lysate. We have studied the RNase H activity on model rA12:α- or ß-d(G2T12G2) hybrids or on mRNA:α- or ß-oligonucleotides hybrids. Specific hybridization protects RNA strech when using α-oligonucleotides but not ß-oligonucleotides. Thus, our results show the inability of RNase H to degrade RNA in α-oligodeoxyribonucleotides:RNA duplexes. © 1987 IRL Press Limited.