PROPERTIES OF NICKED AND CIRCULAR DUMBBELL RNA DNA CHIMERIC OLIGONUCLEOTIDES CONTAINING ANTISENSE PHOSPHODIESTER OLIGODEOXYNUCLEOTIDES/

We have designed a new class of oligonucleotides, 'dumbbell RNA/DNA ch imeric phosphodiester oligonucleotides', consisting of a sense RNA seq uence and its complementary antisense DNA sequence, with two hairpin l oop structures. The reaction of the Nicked (NDRDON) and Circular (CDRN ON) dumbbell DNA/RNA chimeric oligonucleotides with RNase H gave the c orresponding antisense phosphodiester oligodeoxynucleotide together wi th the sense RNA cleavage products. The liberated antisense phosphodie ster oligodeoxynucleotide was bound to the target 45 mer RNA, which ga ve 45 mer RNA cleavage products by treatment with RNase H. The circula r dumbbell RNA/DNA chimeric oligonucleotide showed more nuclease resis tance than the linear antisense phosphodiester oligodeoxynucleotide (a nti-ODN) and the nicked dumbbell RNA/DNA chimeric oligodeoxynucleotide . The circularization, achieved by joining the 3' and the 5' ends of R NA/DNA chimeric oligonucleotides containing two hairpin loop structure s, increases the oligonucleotide uptake into cells, as compared with t he nicked dumbbell RNA/DNA chimeric oligonucleotide and the linear ant isense phosphodiester oligodeoxynucleotides. When the circular dumbbel l RNA/DNA chimeric oligonucleotide is directly delivered into retrovir us infected cells, its antisense phosphodiester oligodeoxynucleotide f unction appears. (C) 1998 Elsevier Science Ltd. All rights reserved.