Nav2 channel gene-deficient non-human animals

Abstract

An object of the present invention is to provide a null mutant non-human animal showing salt intake behavior similar to that of wild-type animals under water-sufficient conditions and showing much more intakes of hypertonic saline compared with wild-type animals under water- and salt-depleted conditions, for example, an Na v 2 gene-deficient non-human animal, which is useful as a model animal of excessive salt intake experiments. The object will be attained by following process: mouse genomic libraries are screened with rat NaG cDNA as a probe, then Na v 2 gene of genomic DNA is isolated, and a targeting vector is constructed by inserting marker gene such as neo gene into the exon of Na v 2. After thus constructed targeting vector is induced to ES cells, homologously recombined ES cells are selected, then germ line chimeric mice are constructed with this ES cells strain, and they are hybridized with the wild-type mice and heterozygous mutant mice are obtained. By intercrossing of thus obtained heterozygous mutant mice, Na v 2 knockout mice are constructed.

What is claimed is:  
     
         1 . A null mutant non-human animal characterized in showing salt intake behavior similar to that of wild-type animals under water-sufficient conditions and showing much more intakes of hypertonic saline compared with wild-type animals under water- and salt-depleted conditions.  
     
     
         2 . The null mutant non-human animal according to  claim 1 , wherein the function of Na v 2 gene is deficient on its chromosome.  
     
     
         3 . The null mutant non-human animal according to  claim 2 , wherein the non-human animal is a rodent.  
     
     
         4 . The null mutant non-human animal according to  claim 3 , wherein the rodent is a mouse.  
     
     
         5 . A gene that codes for a protein acting as a sensor of extracellular sodium ion level.  
     
     
         6 . The gene according to  claim 5 , wherein the protein is comprised of amino acid sequence shown in Seq. ID No. 3, or is comprised of amino acid sequence where one or a few amino acids are deficient, substituted, or added, in amino acid sequence shown in Seq. ID No. 3.  
     
     
         7 . The gene according to  claim 5 , which is comprised of DNA that contains a base sequence shown in Seq. ID No. 2 or its complimentary sequence, and a part or whole of those sequences.  
     
     
         8 . The gene according to  claim 5 , which is comprised of DNA being hybridized under stringent conditions with DNA that contains a base sequence shown in Seq. ID No. 2 or its complimentary sequence, and a part of or whole of those sequences.  
     
     
         9 . A protein acting as a sensor of extracellular sodium ion level.  
     
     
         10 . The protein according to  claim 9 , which is comprised of amino acid sequence shown in Seq. ID No. 3.  
     
     
         11 . The protein according to  claim 9 , which is comprised of amino acid sequence where one or a few amino acids are deficient, substituted, or added, in amino acid sequence shown in Seq. ID No. 3.  
     
     
         12 . A fusion protein created by combining a protein acting as a sensor of extracellular sodium ion level and a marker protein and/or a peptide tag.  
     
     
         13 . The fusion protein according to  claim 12 , wherein the protein acting as a sensor of extracellular sodium ion level is the protein according to claims  10  or  11 .  
     
     
         14 . An antibody which specifically combines with a protein acting as a sensor of extracellular sodium ion level.  
     
     
         15 . The antibody according to  claim 14 , wherein the protein acting as a sensor of extracellular sodium ion level is the protein according to claims  10  or  11 .  
     
     
         16 . The antibody according to claims  14  or  15 , wherein the antibody is a monoclonal antibody.  
     
     
         17 . A host cell which contains an expression system that can express a protein acting as a sensor of extracellular sodium ion level.  
     
     
         18 . The host cell according to  claim 17 , wherein the protein acting as a sensor of extracellular sodium ion level is the protein according to claims  10  or  11 .  
     
     
         19 . A transgenic non-human animal which excessively expresses a protein acting as a sensor of extracellular sodium ion level.  
     
     
         20 . The transgenic non-human animal according to  claim 19 , wherein the protein acting as a sensor of extracellular sodium ion level is the protein according to claims  10  or  11 .  
     
     
         21 . The transgenic non-human animal according to claims  19  or  20 , wherein the non-human animal is a mouse or a rat.  
     
     
         22 . A method of screening a material that promotes or suppresses the function or the expression of a protein acting as a sensor of extracellular sodium ion level characterized in using a cell that expresses a protein acting as a sensor of extracellular sodium ion level, and a subject material.  
     
     
         23 . The method of screening a material that promotes or suppresses the function or the expression of a protein acting as a sensor of extracellular sodium ion level according to  claim 22 , wherein the cell that expresses a protein acting as a sensor of extracellular sodium ion level is the host cell according to claims  17  or  18 .  
     
     
         24 . A method of screening a material that promotes or suppresses the function or the expression of a protein acting as a sensor of extracellular sodium ion level characterized in using the non-human animal according to any one of  claims 1  to  4  or the non-human animal according to any one of  claims 19  to  21 , and a subject material.  
     
     
         25 . A material that promotes or suppresses the function or the expression of a protein acting as a sensor of extracellular sodium ion level characterized in being available through the screening method according to any one of  claims 22  to  24 .  
     
     
         26 . A medical compound used for curing patients who need promotion of the function or enhancement of the expression of a protein acting as a sensor of extracellular sodium ion level, and containing the protein according to any one of  claims 9  to  11  or the material that promotes the function or the expression of a protein acting as a sensor of extracellular sodium ion level according to  claim 25  as its effective components.  
     
     
         27 . A medical compound used for curing patients who need suppression of the function or the expression of a protein acting as a sensor of extracellular sodium ion level, and containing the protein according to any one of  claims 9  to  11  or the material that suppresses the function or the expression of a protein acting as a sensor of extracellular sodium ion level according to  claim 25  as its effective components.