Y2H random library screen. The bait construct (DBD fusion protein) and the prey library (AD fusions with a cDNA or random genomic library) in haploid yeast strains are mixed in a 1:1 ratio. The mating culture is plated on a YEPAD agar plate. After incubation of mating plates for 6 h at 30°C, the diploid cells are transferred to –LTH plates (with or without 3-AT) for selection. The interacting preys are then identified by PCR amplification and sequencing of the vector inserts.