Murine dopamine transporter proximal promoter sequences do not direct lacZ transgene expression to ventral midbrain

Dopamine is an important neurotransmitter involved in a variety of central nervous system functions including locomotion, cognition and emotions. The dopamine transporter is uniquely expressed on dopamine neurons, where it's uptake of dopamine constitutes the primary mechanism for terminating dopamine neurotransmission. Although dopamine transporter (DAT1) sequences have been isolated from several organisms, little is known about the genomic regulatory elements required for expression. This work describes transgenic analysis of a series of murine DAT1 promoter fusions to the lacZ reporter gene to localize putative promoter elements. Despite lacZ expression from these constructs in cultured cells, no expression was observed in any dopaminergic loci from either adult or embryonic mouse brains, for any of the four constructs described. Thus, the murine DAT gene sequences sufficient for activating expression are not located within 2.8 kb 5 to the transcription start site, or within the first eight kb of transcribed sequences.