The way we test the system
Clone human OR1A1 and OR1D2 with a rho tag and express them on the membrane of HEK293 cells. Test the sensitivity and specificity of this basic odor biosensors with their cognate odors ethanethiol or lilial.
Construct signaling amplification circuit with CRISPRa systems. Design multiple sgRNAs targeting CREB1, GNAL, RTP1 and RIC8B and evaluate their activation performance in HEK293 cells to pick out the most effective ones.
Introduce the pooled lentiviral CRISPRa-based signaling amplification components into the basic odor biosensors generated in step 1, and evaluate the performance of such 'iSmeller' in contrast to the basic version. We expect that this 'iSmeller' will significantly increase the sensitivity and/or specificity of the odor biosensor.