Oligonucleotides comprised of alternating 2′-Deoxy-2′-fluoro-β- -arabinonucleosides and -2′-deoxyribonucleosides (2′F-ANA/DNA ‘Altimers’) induce efficient RNA cleavage mediated by RNase H

Chimeric oligonucleotides comprised of alternating residues of 2′-deoxy-2′-fluoro- -arabinonucleic acid (2′F-ANA) and DNA were synthesized and evaluated for an important antisense property—the ability to elicit ribonuclease H (RNase H) degradation of complementary RNA. Experiments used both human RNase HII and Escherichia coli RNase HI. Mixed backbone oligomers comprising alternating three-nucleotide segments of 2′F-ANA and three-nucleotide segments of DNA were the most efficient at eliciting RNase H degradation of target RNA, and were significantly better than oligonucleotides entirely composed of DNA, suggesting that these mixed backbone oligonucleotides may be potent antisense agents.