Mice homozygous for this dopamine transporter IRES-cre (DATIREScre) knock-in allele are viable and fertile. Cre recombinase activity is observed as early as embryonic day 15, and co-localizes with endogenous gene expression in adult dopaminergic cell groups (substantia nigra (SN) and ventral tegmental area (VTA), as well as in the retrorubral field). Lesser Cre recombinase activity occurs in adult olfactory bulb glomeruli, mimicking the known lower Slc6a3 (or DAT) expression in this tissue. Although the pattern and intensity of DAT immunostaining in the SN, VTA and striatum do not differ between wild-type and mutant mice, striatum DAT protein levels are moderately reduced (17%) in heterozygotes and significantly reduced (47%) in homozygotes. This diminution in homozygous striatum is associated with significantly increased neuropeptide PDyn (but not D1, D2, or PPE) mRNA levels compared to wild-type, while such an increase is not observed in heterozygotes. When bred with mice containing a loxP-flanked sequence of interest, Cre-mediated recombination will result in deletion of the flanked genome in dopaminergic neurons. As such, these mutant mice may be useful in neurobiological studies to facilitate the analysis of gene function in dopaminergic neurons, such as drug addiction or Parkinson's disease.
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype could vary from that originally described. The strain description will be modified as published results become available.
