Genetic suppression and replacement

Abstract

A strategy for suppressing specifically or partially specifically an endogenous gene and introducing a replacement gene, said strategy comprising the steps of: 1. providing suppressing nucleic acids or other suppression effectors able to bind to an endogenous gene, gene transcript or gene product to be suppressed and 2. providing genomic DNA or cDNA (complete or partial) encoding a replacement gene wherein the suppressing nucleic acids are unable to bind to equivalent regions in the genomic DNA or cDNA to prevent expression of the replacement gene. The replacement nucleic acids have modifications in one or more third base (wobble) positions such that replacement nucleic acids still code for the wild type or equivalent amino acids.

1 . A strategy for suppressing or partially suppressing an endogenous gene and replacing the suppressed gene with a nucleic acid sequence that differs from the endogenous gene, wherein the suppressing agent comprises at least one suppressor selected from the group consisting of an antisense nucleic acid, a peptide nucleic acid, a nucleic acid capable of forming a triple helix, and a ribozyme targeted to the endogenous gene or gene transcript, wherein the replacement nucleic acid sequence encodes at least part of a gene product and is not suppressed by a suppression agent or is suppressed less efficiently by a suppression agent, and wherein the replacement nucleic acid sequence comprises amino acid codons that encode at least part of the gene product, and have modifications at one or more wobble sites such that replacement nucleic acid still encodes the wild type or equivalent amino acids.  
     
     
         2 . A medicament comprising either one or both of a gene suppressing agent and a nucleic acid encoding at least part of a replacement gene product, for use in a strategy as claimed in  claim 1 .  
     
     
         3 . A strategy for suppressing or partially suppressing an endogenous gene and introducing a replacement gene the strategy comprising the steps of: 
 a. providing a suppression nucleic acid able to recognise, bind or cleave an endogenous gene, gene transcript or gene product to be suppressed; and    b. providing complete or partial genomic DNA or cDNA encoding a replacement gene, wherein the suppression nucleic acid is unable to recognise, bind or cleave or able to recognise, bind or cleave less efficiently, equivalent regions in the genomic DNA or cDNA to prevent suppression of the replacement gene, wherein the coding sequence of the replacement nucleic acid has been altered to prevent or reduce efficiency of suppression and wherein the replacement nucleic acid has modifications in one or more wobble sites such that the replacement nucleic acid still codes for the wild type or equivalent amino acids.    
     
     
         4 . The use of a strategy as claimed in  claim 3  in the preparation of a medicament for the treatment of an autosomal dominant disease caused by an endogenous target gene wherein the disease is caused by different mutations in the same gene in different patients.  
     
     
         5 . The use of: 
 a. a vector containing a suppression effector, the suppression effector able to recognise, bind or cleave a coding sequence of a target endogenous gene; and    b. a vector containing a replacement nucleic acid in the form of genomic DNA, cDNA or RNA, which contains altered wobble sites such that the replacement nucleic acid cannot be recognised, bound or cleaved by the suppression effector or are recognised, bound or cleaved less efficiently by the suppression effector, which suppression effector is targeted towards a coding sequence of the endogenous gene and provides the wild type gene product and wherein the difference between the endogenous gene and the replacement gene enables the expression of the replacement gene;    in the preparation of a medicament for the treatment of an autosomal dominant disease caused by the endogenous gene wherein the disease is caused by different mutations in the same gene in different patients.    
     
     
         6 . A use as claimed in  claim 5  wherein the disease is a polygenic disorder.  
     
     
         7 . A use as claimed in  claim 5  wherein the suppressor and/or replacement gene is administered alone or in a vector chosen from DNA plasmid vectors, RNA or DNA viral vectors.  
     
     
         8 . A use as claimed in  claim 5  wherein the suppressor and/or replacement gene is combined with lipids, polymers or other derivatives.  
     
     
         9 . A use as claimed in  claim 5  wherein the replacement gene is altered from the wild type gene and provides a beneficial effect when compared to the wild type gene.