Figure 1.

Outline of the comprehensive two-hybrid analysis. We cloned almost all yeast ORFs individually as a DNA-binding domain fusion (bait) in a MATa strain and as an activation domain fusion (prey) in a MATα strain, and subsequently divided them into pools, each containing 96 clones. These bait and prey clone pools were systematically mated with each other, and the diploid cells formed were selected for the simultaneous activation of three reporter genes (ADE2, HIS3, andURA3) followed by sequence tagging to obtain ISTs.