Genetic inhibition by double-stranded RNA

Abstract

A process is provided of introducing an RNA into a living cell to inhibit gene expression of a target gene in that cell. The process may be practiced ex vivo or in vivo. The RNA has a region with double-stranded structure. Inhibition is sequence-specific in that the nucleotide sequences of the duplex region of the RNA and of a portion of the target gene are identical. The present invention is distinguished from prior art interference in gene expression by antisense or triple-strand methods.

1 - 21 . (canceled)  
     
     
         22 . A method to inhibit expression of a target gene comprising: 
 (a) providing an organism containing a target cell, wherein the target cell contains the target gene and the target gene is expressed in the target cell;    (b) contacting a ribonucleic acid (RNA) with the organism, wherein the RNA is comprised of a double-stranded structure with duplexed ribonucleic acid strands and one of the strands is able to duplex with a portion of the target gene; and    (c) introducing the RNA into the target cell, thereby inhibiting expression of the target gene.    
     
     
         23 . The method of  claim 22  in which the organism is an animal.  
     
     
         24 . The method of  claim 22  in which the organism is a plant.  
     
     
         25 . The method of  claim 22  in which the organism is an invertebrate animal.  
     
     
         26 . The method of  claim 22  in which the organism is a nematode.  
     
     
         27 . The method of  claim 26  in which a formulation comprised of the RNA is applied on or adjacent to a plant, and disease associated with nematode infection of the plant is thereby reduced.  
     
     
         28 . The method of  claim 22  in which the identical nucleotide sequence is at least 50 nucleotides in length.  
     
     
         29 . The method of  claim 22  in which the expression of the target gene is inhibited by at least 10%.  
     
     
         30 . The method of  claim 22  in which the RNA is introduced within a body cavity of the organism and outside the target cell.  
     
     
         31 . The method of  claim 22  in which the RNA is introduced by extracellular injection into the organism.  
     
     
         32 . The method of  claim 22  in which the organism is contacted with the RNA by feeding the organism food containing the RNA.  
     
     
         33 . The method of  claim 32  in which a genetically-engineered host transcribing the RNA comprises the food.  
     
     
         34 . The method of  claim 22  in which at least one strand of the RNA is produced by transcription of an expression construct.  
     
     
         35 . The method of  claim 35  in which the organism is a nematode and the expression construct is contained in a plant, and disease associated with nematode infection of the plant is thereby reduced.  
     
     
         36 . A cell containing an expression construct, 
 wherein the expression construct transcribes at least one ribonucleic acid (RNA) and the RNA forms a double-stranded structure with duplexed strands of ribonucleic acid,    whereby said cell contains the double-stranded RNA structure and is able to inhibit expression of a target gene when the RNA is contacted with an organism containing the target gene.    
     
     
         37 . A transgenic animal containing said cell of  claim 36 .  
     
     
         38 . A transgenic plant containing said cell of  claim 36 .  
     
     
         39 . A kit comprising reagents for inhibiting expression of a target gene in a cell, 
 wherein said kit comprises a means for introduction of a ribonucleic acid (RNA) into the cell in an amount sufficient to inhibit expression of the target gene, and    wherein the RNA has a double-stranded structure with an identical nucleotide sequence as compared to a portion of the target gene.