Figure 1.
Three types of Y1H systems. (A–E) Diploid-mating system. A haploid MATa strain (light blue for MATa mating type) (A) was transformed with a plasmid carrying the transcription factor gene (TF) (B). An antibiotic Aureobasidin A (AbA) selection marker (AbAr) driven by a promoter (Pro) of a secondary cell wall biosynthesis gene was chromosomally integrated into a haploid MATα strain (light green for MATα mating type) (D) at the ura3 locus to yield the MATα_Pro strain (E). The TF-transformed strain (B) was then mated with the MATα_Pro (E) to produce a diploid strain (C). (D–F) Haploid-transformation system. Two-round transformation of a haploid MATα strain (D) were carried out for promoter integration (E) and TF plasmid introduction (F). (D,E, G–J) Meiosis-directed system. MMa and MMα (Magic Marker; in blue and green) were used to replace CAN1 and LYP1, resulting in the Y1HGold-MM strain (can1Δ/lyp1Δ) (G). A TF plasmid was transformed into the Y1HGold-MM strain (H) followed by mating with the MATα_Pro strain (E), resulting in a heterologous diploid strain (CAN1/can1Δ/LYP1/lyp1Δ) (I). This diploid strain then underwent meiosis, and the MATa cells (J) were selected via MMa and MMα.