We performed a similar experiment to determine if deletion of the CLZ domain permitted incorporation of multiple CNGB1 subunits into the heteromeric channels. If there are multiple CNGB1 subunits in the heteromeric channels, then we should observe FRET between CNGB1 subunits when fused to eCFP and eYFP and co-expressed with CNGA1-∆CLZ subunits (Fig. 4a) .