Assay Method Information

Assay Name:  Human TAAR1 assay
Description:  For the construction of expression plasmids the coding sequences of human TAAR 1 were amplified from genomic DNA essentially as described by Lindemann et al.[14]. The Expand High Fidelity PCR System (Roche Diagnostics) was used with 1.5 mM Mg2+ and purified PCR products were cloned into pCR2.1-TOPO cloning vector (Invitrogen) following the instructions of the manufacturer. PCR products were subcloned into the pIRESneo2 vector (BD Clontech, Palo Alto, Calif.), and expression vectors were sequence verified before introduction in cell lines.HEK293 cells (ATCC # CRL-1573) were cultured essentially as described by Lindemann et al. (2005). For the generation of stably transfected cell lines HEK293 cells were transfected with the pIRESneo2 expression plasmids containing the TAAR coding sequences (described above) with Lipofectamine 2000 (Invitrogen) according to the instructions of the manufacturer, and 24 hrs post transfection the culture medium was supplemented with 1 mg/ml G418 (Sigma, Buchs, Switzerland). After a culture period of about 10 d clones were isolated, expanded and tested for responsiveness to trace amines (all compounds purchased from Sigma) with the cAMP Biotrak Enzyme immunoassay (EIA) System (Amersham) following the non-acetylation EIA procedure provided by the manufacturer. Monoclonal cell lines which displayed a stable EC50 for a culture period of 15 passages were used for all subsequent studies.cAMP measurements were performed as described previously (Revel et al., Proc. Natl. Acad. Sci. USA 2011, 108, 8485-8490). In brief, cells that expressed human TAAR1 were plated on 96-well plates (BIOCOAT 6640; Becton Dickinson, Allschwil, Switzerland) and incubated for 20 h at 37° C. Prior to stimulation of the cells with a broad concentration range of agonists for 30 min at 37° C., the cells were washed with PBS and preincubated with PBS that contained 1 mM 3-isobutyl-1-methylxanthine for 10 min at 37° C. and 5% CO2. Stimulation with 0.2% DMSO was set as the basal level, and the effect of 30 μM β-PEA was set as the maximal response. Subsequently, the cells were lysed, and cAMP assays were performed according to the manufacturer's instructions (cAMP kit; Upstate/Millipore, Schaffhausen, Switzerland). Finally, the plates were read with a luminometer (1420 Multilabel counter; PerkinElmer, Schwerzenbach, Switzerland), and the amount of cAMP was calculated. The results were obtained from at least three independent experiments. Experiments were run in duplicate or triplicate. EC50 values are presented as mean ±standard deviation (in μM).
Affinity data for this assay
 

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