The targeting construct inserted into the locus a CAG promoter, a loxP-flanked STOP cassette with 3 SV40 polyadenylation sequences and the human alpha-synuclein cDNA, woodchuck hepatitis virus posttrascriptional regulatory element (WPRE), and bGH polyl(A). Expression of the gene can only be achieved by cre-mediated removal of the floxed neo STOP cassette. (J:283567)