The transgene contains 9.0 kb of upstream sequence from the rat tyrosine hydroxylase gene that drives dopamine neuron-specific expression of the mouse gene with a silent point mutation at position 1077 (c.1077C->G). This mutation forms a restriction enzyme site and allows for the insertion of 39 nucleotides that produces a duplication of amino acids 353 to 365. An IRES-EGFP and polyadenylation sequence follow the altered mouse gene. Four of six lines have higher EGFP expression than wild-type mice. Lines 1, 2, 3 and 4 contain 181, 227, 141, 97, 42 and 6 copies of the transgene, respectively.