The transgene construct has the optimized phiC31 sequence (phiC31*) downstream of the 9 kb fragment of the rat tyrosine hydroxylase (Th) promoter. A 0.75 kb downstream fragment of the mouse Th gene including the endogenous polyadenylation sequence was included after the phiC31 sequence. Only 1 founder was obtained. In offspring from crosses with R26attR lacz reporter mice, beta-galactosidase activity was observed in brain areas including the olfactory bulb, hypothalamus, midbrain, hindbrain and posterior hindbrain. Dopaminergic cell populations such as those in the substantia nigra, hypothalamus, and periglomerular region of the olfactory bulb and noradrenergic cells of the locus coeruleus showed staining. Some areas not expected to show Th activity such ans the accessory olfactory bulb stained, potentially due to ectopic Th promoter activity.