Insertion of a methylene group into the backbone of an antisense oligonucleotide reveals the importance of deoxyribose recognition by RNase H.

RNase H acts as a key effector in gene knockdown by antisense oligonucleotides (ASOs). Although various chemical modifications have been developed to regulate RNase H-mediated cleavage, precise control is yet to be achieved. In this study, we tried to address the question of whether the interaction of phosphate groups or deoxyriboses is more important in the recognition of DNA/RNA duplex by RNase H.