FIG. 2.

ES cells express DREAADs after Cre-mediated removal of STOP. Colonies from R26-LSL-hM4Di-DREADD-expressing ES cells were fluorescent only when transformed with CMV-Cre (A, B), while non-Cre transfected cells showed no fluorescence (C, D). To visualize membrane localization of DREADDs at the single cell level, Cre recombinase transformed ES cells were plated directly on gelatinized coverslips at low density; cells plated under these conditions show a flat, fibroblast-like morphology. Cells were fixed 2 days later, and treated with primary and secondary antibodies to HA. Confocal microscopy allowed visualizing, separately, cytoplasm and membrane of the same cells. Citrine (green) localizes to the cytoplasm (E), while HA (red) is fused to DREADDs and localizes to the cell membrane (F).