INDUCIBLE SYSTEMS AND METHODS FOR CONTROLLING siRNA EXPRESSION

Abstract

An inducible system and methods for controlling expression of siRNA are provided. An inducible system for producing siRNA only in the presence of HIV TAT, and methods for inhibiting HIV-1 gene expression in cells comprising such inducible system also are provided.

1 . An inducible siRNA system for controlling expression of siRNA comprising a promoter operatively associated with an inducible element and an siRNA operably associated with the promoter, wherein siRNA is produced substantially only in the presence of an inducer which is specific for the inducible element. 
     
     
         2 . The inducible siRNA system of  claim 1 , wherein the siRNA is a short hairpin RNA (shRNA). 
     
     
         3 . The inducible siRNA system of  claim 1 , wherein the promoter is a Pol II promoter. 
     
     
         4 . A cell comprising the inducible siRNA system of  claim 1 . 
     
     
         5 . The inducible siRNA system of  claim 1 , wherein the inducible element is an HIV TAR region, the siRNA encodes a sequence capable of inhibiting HIV replication and the inducer is HIV TAT. 
     
     
         6 . The inducible siRNA system of  claim 5 , wherein the siRNA is a short hairpin RNA (shRNA). 
     
     
         7 . The inducible siRNA system of  claim 5 , wherein the promoter is a Pol II promoter. 
     
     
         8 . An HIV infected cell in which siRNA expression is induced, comprising an inducible siRNA system according to  claim 4 . 
     
     
         9 . A method for inhibiting viral replication in an infected cell comprising:
 introducing into the cell the inducible siRNA system of  claim 1  into the cell in an amount sufficient to inhibit viral replication,   wherein the siRNA encodes a comprising a promoter operatively associated with an inducible element and siRNA encodes a sequence capable of inhibiting viral replication and wherein viral replication is inhibited in the cell by siRNA produced substantially only in the presence of an inducer which is specific for the inducible element.   
     
     
         10 . The method of  claim 9 , wherein the siRNA is a short hairpin RNA (shRNA). 
     
     
         11 . The method of  claim 9 , wherein the virus is HIV, the inducible element is the HIV TAR region and the inducer is HIV TAT. 
     
     
         12 . The method of  claim 9 , wherein the promoter is a Pol II promoter. 
     
     
         13 . The method of  claim 9 , wherein the cell further comprises the inducer. 
     
     
         14 . A method for reducing expression of a target gene in a cell comprising:
 introducing the inducible siRNA system of  claim 1  into the cell in an amount sufficient to reduce expression of the target gene,   wherein the siRNA encodes a sequence that is capable of reducing expression of the target gene and wherein target gene expression is reduced in the cell by siRNA produced substantially only in the presence of an inducer which is specific for the inducible element.   
     
     
         15 . The method of  claim 14 , wherein the siRNA is a short hairpin RNA (shRNA). 
     
     
         16 . The method of  claim 14 , wherein the promoter is a Pol II promoter. 
     
     
         17 . The method of  claim 14 , wherein the cell further comprises the inducer.