Regeneration and neogenesis of retinal photoreceptor cell using otx2 gene

Abstract

The present invention provides a medicine, comprising (a) an Otx2 protein or its partial peptide, or a salt thereof, or (b) a DNA or an RNA encoding an Otx2 protein or its partial peptide. The present medicine is useful as an agent for preventing, treating or suppressing progression of a retinal disease including retinal degeneration. In addition, the present medicine is useful, for example, as an agent for inducing differentiation from a retinal stem cell into a retinal photoreceptor cell, in the transplantation of a cell into the retina of patients suffering from retinal diseases.

1 - 25 . (canceled) 
     
     
         26 . A method for screening a compound having an action of inducing differentiation into a retinal photoreceptor cell, which comprises using, as an index, an expression of, or increase in an expression amount of an Otx2 protein. 
     
     
         27 . The screening method according to  claim 26 , wherein the compound having an action of inducing differentiation into a retinal photoreceptor cell has an action of suppressing differentiation into a bipolar cell, an amacrine cell and a Muller glia cell. 
     
     
         28 . The screening method according to  claim 26 , wherein the Otx2 protein is
 (1) a protein having the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5; or   (2) a protein having   (i) an amino acid sequence in which 1 or 2 amino acid(s) in the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5 is/are deleted,   (ii) an amino acid sequence in which 1 or 2 amino acid(s) is/are added to the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5,   (iii) an amino acid sequence in which 1 or 2 amino acid(s) in the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5 is/are substituted with other amino acid(s), or   (iv) an amino acid sequence as a combination thereof, and having an action of inducing differentiation into a retinal photoreceptor cell, wherein said action is equivalent to that of the protein having the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5.   
     
     
         29 . The screening method according to  claim 26 , wherein the Otx2 protein has the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5. 
     
     
         30 . The screening method according to  claim 26 , wherein a cell having ability of expressing an Otx2 protein is used. 
     
     
         31 . The screening method according to  claim 30 , wherein the cell having ability of expressing an Otx2 protein is a transformant with the DNA having
 (1) a nucleotide sequence of SEQ ID NO: 2, SEQ ID NO: 4 or SEQ ID NO: 6; or   (2) a nucleotide sequence having at least 95% homology with the nucleotide sequence of SEQ ID NO: 2, SEQ ID NO: 4 or SEQ ID NO: 6 and encoding an Otx2 protein having an action of inducing differentiation into a retinal photoreceptor cell, wherein said action is equivalent to that of the protein having the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5.   
     
     
         32 . The screening method according to  claim 30 , wherein the cell having ability of expressing an Otx2 protein is a transformant with the DNA having a nucleotide sequence of SEQ ID NO: 2, SEQ ID NO: 4 or SEQ ID NO: 6. 
     
     
         33 . A method for screening a compound having an action of inducing differentiation into a retinal photoreceptor cell, which comprises (i) a step of a cell having an ability to express an Otx2 protein is cultured in the presence of a test compound; and (ii) a step of detecting expression of the Otx2 protein or measuring an expression amount of the Ox2 protein. 
     
     
         34 . The screening method according to  claim 33 , wherein the compound having an action of inducing differentiation into a retinal photoreceptor cell has an action of suppressing differentiation into a bipolar cell, an amacrine cell and a Muller glia cell. 
     
     
         35 . The screening method according to  claim 33 , wherein the Otx2 protein is
 (1) a protein having the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5; or   (2) a protein having   (i) an amino acid sequence in which 1 or 2 amino acid(s) in the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5 is/are deleted,   (ii) an amino acid sequence in which 1 or 2 amino acid(s) is/are added to the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5,   (iii) an amino acid sequence in which 1 or 2 amino acid(s) in the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5 is/are substituted with other amino acid(s), or   (iv) an amino acid sequence as a combination thereof, and having an action of inducing differentiation into a retinal photoreceptor cell, wherein said action is equivalent to that of the protein having the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5.   
     
     
         36 . The screening method according to  claim 33 , wherein the Otx2 protein has the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5. 
     
     
         37 . The screening method according to  claim 33 , wherein the cell having ability of expressing an Otx2 protein is a transformant with the DNA having
 (1) a nucleotide sequence of SEQ ID NO: 2, SEQ ID NO: 4 or SEQ ID NO: 6; or   (2) a nucleotide sequence having at least 95% homology with the nucleotide sequence of SEQ ID NO: 2, SEQ ID NO: 4 or SEQ ID NO: 6 and encoding an Otx2 protein having an action of inducing differentiation into a retinal photoreceptor cell, wherein said action is equivalent to that of the protein having the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5.   
     
     
         38 . The screening method according to  claim 33 , wherein the cell having ability of expressing an Otx2 protein is a transformant with the DNA having a nucleotide sequence of SEQ ID NO: 2, SEQ ID NO: 4 or SEQ ID NO: 6. 
     
     
         39 . A method for screening a compound having an action of inducing differentiation into a retinal photoreceptor cell, which comprises (i) a step of culturing a cell having an ability to express an Otx2 protein in the presence and absence of a test compound, (ii) a step of measuring an amount of a mRNA encoding the Otx2 protein; and (iii) a step of comparing an amount of expression of the Otx2 mRNA in the presence of the test compound with that in the absence of the test compound. 
     
     
         40 . The screening method according to  claim 39 , wherein the compound having an action of inducing differentiation into a retinal photoreceptor cell has an action of suppressing differentiation into a bipolar cell, an amacrine cell and a Muller glia cell. 
     
     
         41 . The screening method according to  claim 39 , wherein the Otx2 protein is
 (1) a protein having the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5; or   (2) a protein having   (i) an amino acid sequence in which 1 or 2 amino acid(s) in the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5 is/are deleted,   (ii) an amino acid sequence in which 1 or 2 amino acid(s) is/are added to the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5,   (iii) an amino acid sequence in which 1 or 2 amino acid(s) in the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5 is/are substituted with other amino acid(s), or   (iv) an amino acid sequence as a combination thereof, and having an action of inducing differentiation into a retinal photoreceptor cell, wherein said action is equivalent to that of the protein having the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5.   
     
     
         42 . The screening method according to  claim 39 , wherein the Otx2 protein has the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5. 
     
     
         43 . The screening method according to  claim 39 , wherein the cell having ability of expressing an Otx2 protein is a transformant with the DNA having
 (1) a nucleotide sequence of SEQ ID NO: 2, SEQ ID NO: 4 or SEQ ID NO: 6; or   (2) a nucleotide sequence having at least 95% homology with the nucleotide sequence of SEQ ID NO: 2, SEQ ID NO: 4 or SEQ ID NO: 6 and encoding an Otx2 protein having an action of inducing differentiation into a retinal photoreceptor cell, wherein said action is equivalent to that of the protein having the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3 or SEQ ID NO: 5.   
     
     
         44 . The screening method according to  claim 39 , wherein the cell having ability of expressing an Otx2 protein is a transformant with the DNA having a nucleotide sequence of SEQ ID NO: 2, SEQ ID NO: 4 or SEQ ID NO: 6.