Fig. 5. Binding of the WER protein to WBSI in yeast. (A) Schematic diagrams of the reporter genes and the effectors used in this yeast one-hybrid assay. Three tandem repeats of each DNA fragment were inserted upstream of a reporter gene (lacZ) in the vector pLacZi and then yeast reporter strains were made by genomic integration of these reporters. (B) Yeast one-hybrid assay with WBSI as a cis-acting element. AD-WER was expressed in the yeast reporter strains harboring a reporter gene that has the wild-type or one of the mutant derivatives of WBSI in its upstream as shown in A. A ß-galactosidase assay is performed to verify the DNA-protein interaction using CPRG as a substrate.