Double-stranded oligonucleotides

Abstract

Antisense sequences, including duplex RNAi compositions, which possess improved properties over those taught in the prior art are disclosed. The invention provides optimized antisense oligomer compositions and method for making and using the both in in vitro systems and therapeutically. The invention also provides methods of making and using the improved antisense oligomer compositions.

1 . A method for introducing a double-stranded nucleic acid molecule comprising a first strand and a second strand into a eukaryotic cell in vitro, the method comprising contacting the eukaryotic cell with the double-stranded nucleic acid molecule,
 wherein from one to six of the nucleotides at the 5′ terminus of the first strand of the double-stranded nucleic acid molecule are chemically modified at the 2′ positions, wherein said modification is a 2′-O-methyl modification;   wherein from one to six of the nucleotides at the 5′ terminus of the second strand of the double-stranded nucleic acid molecule are chemically modified at the 2′ positions, wherein said modification is a 2′-O-methyl modification;   wherein the double-stranded nucleic acid molecule is between 18 and 30 nucleosides in length; and   wherein the double-stranded nucleic acid molecule is introduced into the eukaryotic cell and participates in RNA interference mediated degradation of RNA which shares sequence complementarity with at least one strand of the double-stranded nucleic acid molecule.   
     
     
         2 . The method of  claim 1 , wherein the double-stranded nucleic acid molecule is between 20 and 30 nucleosides in length. 
     
     
         3 . The method of  claim 1 , wherein the double-stranded nucleic acid molecule is 25 nucleosides in length. 
     
     
         4 . The method of  claim 1 , wherein the double-stranded nucleic acid molecule contains an overhang of at least one nucleoside on at least one end. 
     
     
         5 . The method of  claim 4 , wherein the overhang is a 3′ end overhang. 
     
     
         6 . The method of  claim 4 , wherein the nucleosides of the 3′ end overhang are deoxy T-deoxy T. 
     
     
         7 . The method of  claim 1 , wherein the 2′ chemical modification is on a ribose. 
     
     
         8 . The method of  claim 1 , wherein the double-stranded nucleic acid molecule is RNA. 
     
     
         9 . The method of  claim 1 , wherein the eukaryotic cell is contacted with the double-stranded nucleic molecule in the presence of a transfection reagent. 
     
     
         10 . The method of  claim 9 , wherein the transfection reagent is a cationic lipid. 
     
     
         11 . The method of  claim 1 , wherein the double-stranded nucleic acid molecule is introduced into the eukaryotic cell by electroporation. 
     
     
         12 . The method of  claim 1 , wherein a strand of said double-stranded nucleic acid molecule is complementary to a sequence of an mRNA expressed in said eukaryotic cell. 
     
     
         13 . The method of  claim 12 , wherein said double-stranded nucleic molecule is a double-stranded RNA molecule.