Complex of polysaccharide and double-stranded rna and method of inhibiting expression of a target gene in a cell

Abstract

An object of the present invention is to provide novel double-stranded RNA having an RNA interference effect, in which the cellular uptake and the resistance to enzymatic degradation are improved, without reducing the RNA interference effect. The cellular uptake and the resistance to enzymatic degradation of a complex of a polysaccharide having a β-1,3-glucan skeleton and double-stranded RNA can be significantly improved while maintaining the RNA interference effect, by fulfilling the following conditions (i) to (iii): (i) the double-stranded RNA has a sense strand consisting of a base sequence complementary to a target sequence in a target gene and an antisense strand containing a base sequence complementary to the sense strand, and the double-stranded RNA can inhibit expression of the target gene; (ii) the double-stranded RNA has a single-stranded polydeoxyadenine bound directly or via a linker to the end of at least one of the sense strand and the antisense strand; and (iii) the polysaccharide and the single-stranded polydeoxyadenine form a complex.

1 - 12 . (canceled) 
     
     
         13 . A method of inhibiting expression of a target gene in a cell, comprising:
 a step of introducing a polysaccharide having a β-1,3-glucan skeleton/double-stranded RNA complex into a cell;   wherein said polysaccharide is schizophyllan;   wherein the polysaccharide/double-stranded RNA complex contains double-stranded RNA having a sense strand RNA consisting of a base sequence complementary to a target sequence in a target gene and an antisense strand RNA containing a base sequence complementary to the sense strand RNA, and capable of inhibiting expression of the target gene, the sense strand RNA consisting of 21 ribonucleotides; the antisense strand RNA consisting of 21 ribonucleotides;   wherein the double-stranded RNA has a single-stranded polydeoxyadenine bound directly or via a linker to at least one end of the sense strand and antisense strand; and   wherein the polysaccharide and the single-stranded polydeoxyadenine from a complex.   
     
     
         14 . The method of inhibiting expression of a target gene in a cell as defined in  claim 13 , wherein the single-stranded polydeoxyadenine and two polysaccharides form a triple helical structure. 
     
     
         15 . The method of inhibiting expression of a target gene in a cell as defined in  claim 13 , wherein the single-stranded polydeoxyadenine consists of 20 to 100 deoxyadenines as disclosed in SEQ ID NO: 13. 
     
     
         16 . The method of inhibiting expression of a target gene in a cell as defined in  claim 13 , the single-stranded polydeoxyadenine is bound directly or via a linker to the 5′ and/or 3′ end of the sense strand RNA or antisense strand RNA. 
     
     
         17 . The method of inhibiting expression of a target gene in a cell as defined in  claim 13 , the polysaccharide is a β-1,3-glucan to which a functional molecule is bound. 
     
     
         18 . The method of inhibiting expression of a target gene in a cell as defined in  claim 13 , wherein the target gene of the double-stranded RNA is endogenous to a cell having a receptor that binds to the polysaccharide. 
     
     
         19 . The method of inhibiting expression of a target gene in a cell as defined in  claim 18 , wherein the cell is a cell that expresses Dectin-1 on the membrane surface of the cell.