Generation of a transgenic model to address regulation and function of the human neurokinin 1 receptor (NK1R)

We have generated mouse transgenic lines using yeast artificial chromosome (YAC) technology which demonstrate expression from the human NK1 receptor (NK1R) locus. We introduced a 380 kb fragment encompassing the human NK1R gene and flanking regions which we hoped would recapitulate the expected endogenous expression of the human gene. To visualise this expression the NK1 locus co-expresses the green fluorescence protein gene (GFP) under the control of an internal ribosome entry site (IRES) sequence. We have generated five mouse lines that express the human NK1 receptor gene with and without the marker gene. All the lines incorporating the marker gene appear to exhibit the same expression pattern in analysis of selected anatomical regions throughout the mouse. The lack of a human specific NK1R antibody determined that we could not distinguish between expression of the transgene and endogenous NK1R. Our analysis has shown transgene expression in brain areas known to express NK1R in human such as the hippocampus and caudate putamen. The majority of these cells were also positive for GFP fluorescence. These transgenic lines may prove a good pre-clinical model as drugs can be addressed against both the human receptor and modulators of its expression in vivo.