The transgene comprises a cDNA encoding full length human atrophin 1 containing a 26 residue polyglutamine tract, encoded by 26 CAG repeats, inserted into an expression cassette containing the promoter, 5' intronic and 5' and 3' untranslated region sequences of the mouse prion protein gene. This transgenic line carries more than ten copies of the construct. Northern blot analysis shows similar levels of expression of human atrophin 1 and native prion protein mRNA in the brain, where presence of the human protein is confirmed by immunoblot analysis. (J:70362)