Establish a recombinant yeast detection system to study the effect of MIP on transactivation function of hMafF in US2-driven gene transcription.

The human gene MafF (hMafF) is a member of bZip transcription factor Maf family, but it alone cannot activate its target genes. In 2006, a novel hMafF interacting protein (MIP) was identified. Transient transfection assay in Hela cells suggested that co-expression of MIP and hMafF could activate US2-driven transcription. In this work, we constructed a series of plasmids and transformed YM4271 yeast strain to establish a recombinant yeast detection system. In this system, MIP's expression level could be regulated using glucose incubation or galactose-induced incubation. The expression level of reporter gene LacZ in obtained recombinant yeast strains was measured using quantitative liquid assay. By comparing and analyzing the beta-galactosidase activities of different yeast strains or the same yeast strain in different culture media, the effect of MIP on transactivation driven by nUS2-hMafF was finally determined. Only in the presence of both MIP and hMafF could the nUS2-pLacZi reporter in yeast genome be activated. More importantly, this work established a novel recombinant yeast detection system, which may serve as a powerful tool to study the regulatory mechanisms of transcription complex in the future.