An olfactory receptor protein of rats, I7, was expressed on the surface of human embryonic kidney (HEK)-293 cells. For targeting and detecting the protein, rho-tag import sequence was fused with the I7 protein. The olfactory receptor was expressed on the plasma membrane of HEK-293 cells, and stable cell lines regulated by an inducer were obtained. The expression on the cell surface was confirmed by immunocytochemical and Western blotting methods, and the binding of specific odorant molecules to the olfactory receptor was measured using quartz crystal microbalance (QCM). The results for QCM coated with cells containing the olfactory receptor showed that the expressed protein I7 strongly interacted with octyl aldehyde (octanal), which is an odorant specific to the I7 protein. Several other odorants were tested, and the results showed that I7 interacted differently with them. The QCM response to the serial concentrations of octyl aldehyde showed that the response is dose dependent. All these results indicate that the I7 receptor protein expressed on the surface of the heterologous cell system is sensitive to the specific odorant and can be used for the quantitative measurement of the odorant.
Bibliographical noteFunding Information:
This work was supported by the Korea Science & Engineering Foundation through the Nano-Bioelectronics and Systems Research Center, Seoul National University, Seoul Korea. We thank Randall R. Reed (Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA) for the rho-tag gene, Akihito Yasuoka (Bio-oriented Technology Research Advancement Institution, Saitama, Japan) for the pVL-I7, and Paul A. Hargrave (J. Hillis Miller Health Center, Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA) for the B6-30 cell line.
- HEK-293 cell
- Octyl aldehyde
- Olfactory receptor protein
- Quartz crystal microbalance