PrP-like gene

Abstract

The present invention provides nucleic acids encoding the Doppel (“Dpl”) protein, Dpl peptides, and assays utilizing the Dpl nucleic acids and/or peptides. In related aspects the invention features expression vectors and host cells comprising nucleic acids that encode a human Dpl polypeptide. The present invention also relates to antibodies that bind specifically to a human Dpl polypeptide, methods for producing human Dpl polypeptides, methods for identifying cells expressing Dpl, methods for using the Dpl gene and the Dpl polypeptide to alter cellular function and prion infectivity in culture or in vivo, and identification of individuals at risk for prion disorders by detecting alteration in Dpl coding and regulatory sequences and Dpl expression levels.

What is claimed is:  
     
         1 . An isolated human doppel (Dpl) polypeptide.  
     
     
         2 . The human Dpl polypeptide of    claim 1   , comprising an amino acid sequence of SEQ ID NO:2.  
     
     
         3 . An isolated nucleic acid sequence or complement thereof comprising a nucleic acid sequence encoding a human Dpl polypeptide of    claim 1   .  
     
     
         4 . An isolated nucleic acid sequence of    claim 3    comprising a nucleic acid sequence of SEQ ID NO:1.  
     
     
         5 . A recombinant expression vector comprising the nucleic acid sequence of    claim 3   .  
     
     
         6 . An isolated recombinant host cell containing the nucleic acid sequence of    claim 1   .  
     
     
         7 . A transgenic animal, comprising 
 a genome wherein at least one allele of an endogenous Dpl gene is altered.    
     
     
         8 . The transgenic animal of    claim 7   , wherein the alteration results in enhanced expression from the Dpl gene.  
     
     
         9 . The transgenic animal of    claim 7   , wherein the animal further comprises 
 a genome wherein at least one endogenous PrP allele is ablated.    
     
     
         10 . The transgenic animal of    claim 9   , wherein said genome having operatively inserted therein an exogenous PrP gene from a genetically diverse species.  
     
     
         11 . A method for producing the human Dpl polypeptide of    claim 1   , the method comprising the steps of: 
 (a) culturing a recombinant host cell containing a human Dpl polypeptide-encoding nucleic acid sequence under conditions suitable for the expression of the polypeptide; and    (b) recovering the polypeptide from the host cell culture.    
     
     
         12 . An isolated antibody that specifically binds a human Dpl polypeptide of    claim 1   .  
     
     
         13 . The isolated antibody of    claim 12   , wherein the antibody recognizes an epitope defined by SEQ ID NO:3.  
     
     
         14 . A method for identifying a nucleic acid homologous to the nucleic acid of    claim 3   , the method comprising the steps of: 
 contacting a nucleic acid probe with a test nucleic acid, the probe comprising at least 15 contiguous nucleotides of a nucleic acid sequence encoding a human Dpl polypeptide; and    detecting hybridization of the probe with the test nucleic acid;    wherein detection of hybridization of the probe to the test nucleic acid indicates that the nucleic acid shares sequence homology with the human Dpl polypeptide-encoding nucleic acid.    
     
     
         15 . A method for facilitating the detection of prion infectivity, the method comprising the step of: 
 obtaining sample tissue from an animal to be tested;    inoculating the transgenic animal of    claim 7    with the sample; and    observing the transgenic animal for symptoms of prion disease.    
     
     
         16 . The method of    claim 15   , wherein the test animal is selected from the group consisting of human, cow, sheep, pig, horse, cat, dog, turkey or chicken, and the transgenic animal is selected from the group consisting of: mice, rats, rabbits, hamsters and guinea pigs.  
     
     
         17 . A method for identifying a biologically active agent that modulates human doppel (Dpl) activity, the method comprising: 
 combining a candidate agent with any one of: 
 (a) a mammalian Dpl polypeptide;  
 (b) a cell comprising a nucleic acid encoding a mammalian Dpl polypeptide;  
 (c) a cell comprising a nucleic acid encoding a mammalian Dpl promoter sequence operably linked to a nucleic acid encoding a report gene; or  
 (d) a non-human transgenic animal model comprising one of:(i) an exogenous and stably transmitted human Dpl gene sequence; or (iii) a mammalian Dpl promoter sequence operably linked to a reporter gene; and  
   determining the effect of said agent on Dpl activity.    
     
     
         18 . A method for detecting in a subject a predisposition to a neurodegenerative disorder associated with a defect in doppel (Dpl) activity, the method comprising: 
 analyzing the genomic DNA or mRNA of an individual for the presence of at least one predisposing alteration in a genomic Dpl sequence;    wherein the presence of the altered genomic Dpl sequence is indicative of an increased susceptibility to a defect in neuronal outgrowth or degeneration.    
     
     
         19 . The method of    claim 17   , wherein the alteration is in a Dpl promoter sequence.  
     
     
         20 . The method of    claim 17   , wherein the alteration is in a genomic sequence encoding a Dpl polypeptide.  
     
     
         21 . An isolated Dpl nucleic acid, wherein said nucleic acid is comprised in part of codons from a Dpl gene of a genetically diverse species.  
     
     
         22 . A transgenic, hybrid, non-human mammal having a genome comprised of an ablated endogenous Dpl gene.  
     
     
         23 . The transgenic animal of    claim 22   , wherein the genome further comprises an exogenous Dpl gene selected from the group consisting of a Dpl gene from a genetically diverse species and an artificial gene comprised in part of codons from a Dpl gene of a genetically diverse species, the hybrid mammal being characterized by being susceptible to infection which generally only infects a genetically diverse test animal.  
     
     
         24 . The hybrid mammal of    claim 23   , wherein the hybrid mammal belongs to a genus selected from the group consisting of Mus, Rattus, Oryctolagus and Mesocricetus and the test animal is selected from the group consisting of Bos, Ovis, Sus and Homo.  
     
     
         25 . A method of diagnosis of neurodegenerative disease, comprising the steps of 
 obtaining a sample from a mammal suspected of having a neurodegenerative disorder; and    detecting the presence of one or more conformations of Dpl protein in the sample.    
     
     
         26 . The method of    claim 25   , wherein the neurodegenerative disease is associated with Purkinje cell degeneration.