MaV203 competent yeast cells are designed for use in the ProQuest™ Dual Mix System (Figure 1). Saccharomyces cerevisiae strain MaV203 contains deletions in the endogenous GAL4 and GAL80 genes for use in GAL4-based Dual hybrid system. This strain also has leu2 and trp1 mutations and can be used in ProQuest™ bait and prey vector screening. MaV203 contains threeGAL4-inducible reporters that provide four phenotypes to more easily identify true interactors (Fig. 2). MaV203 competent cells have the following properties:

• Transformation (250 μl cells) efficiency yields >1 x 10⁶ colonies
• Control DNA pMAB12 is used to confirm transformation Efficiency and preparation of selection media
• Prequalified PEG/lithium acetate maximizes transformant numbers
• Competent cells formatted with vector DNA already included