Functional expression of Rho-mOREG using a CNG-based assay. (A) HEK293 cells transiently transfected with Rho-mOREG and CNG were assayed for increases in intracellular calcium in response to 100 uM eugenol. Images contain ~2000 confluent cells and represent responses at the indicated times following odorant stimulation. Scale bar is 300 um. Responses were observed in ~10% of total cells or ~20% of transfected cells (~50% transfection efficiency). (B) Quantitation of cells expressing vector only (a), Rho-mOREG only (b), CNG only (c), Rho-mOREG and CNG (d and e) following stimulation with 100 uM eugenol (a-d) or 100 uM heptanal plus 100 uM octanal (e). * p < 0.001 compared to cells expressing vector only (a).