Fig 1. HEK293 cell-based screening of human ORs for six perfumery raw materials.

A. Primary screening of human ORs using 384-well plates. 378 ORs were expressed in HEK293 cells, and they were stimulated with a single concentration of each odorant. HEK293 cells were co-transfected with each OR, CRE/luc2PpGL4.29, pRL-CMV, and RTP1S. Odorant solutions were diluted in the growth medium without FBS. X-axis lists each of the 378 ORs, and color bars represent OR families. Y-axis indicates the response of cells expressing each OR as fold increase where a signal from stimulated cells was divided by that from non-stimulated cells expressing the same OR (mean values from two screening replicates). B. Verification of dose-dependent responsiveness of cell-expressing candidate ORs using 96-well plates. Each OR was co-transfected with CRE/luc2PpGL4.29, pRL-CMV, and RTP1S. 32 pairs of ORs and their agonists that meet our statistical criteria for dose-dependent responses are shown. The grey-shaded ORs do not fit a sigmoidal curve because their responses were not saturated in the range of concentrations tested due to less sensitivity. Y-axis indicates the fold increase value, and data are shown as mean ± SE from three independent experiments.