Figure 2.

Directed yeast two-hybrid assays. Yeast strain AH109 was transformed with bait plasmid pGBKT7 (Vec) or its derivative pGBK-DBP4 or PGBK-ENP2, and prey plasmid pGADT7 (Vec) or its derivatives pGAD-DBP4, pGAD-ENP2, pGAD-BFR2 and pGAD-NOP6. The bait and prey plasmids, respectively, carry TRP1 and LEU2 auxotrophic markers that allow growth on medium lacking tryptophan and leucine (upper panel). Interactions between bait and prey hybrid proteins activate transcription of the HIS3 reporter gene, which is monitored by growth on medium lacking histidine; addition of 2 or 20 mM 3-AT to this medium enhances the stringency of the HIS3 reporter, allowing detection of the strongest two-hybrid interactions (middle and lower panels, respectively).