Fig. 1.

Schematic depicting chemical complementation. For selection, yeast strain PJ69-4A has the ADE2 gene under the control of a Gal4 response element (Gal4 RE). This strain is transformed with a plasmid expressing ACTR:GAD (B.A., E. I. Chang, L.J.S., and D.F.D., unpublished data). Plasmids created through homologous recombination in PJ69-4A express a variant, GBD:RXR. In media lacking Ade, yeast will grow only in the presence of a ligand that causes the RXR LBD to associate with ACTR and activate transcription of ADE2. For clarity, only one ACTR:GAD is depicted.