Mediator Subunits MED16, MED14, and MED2 Are Required for Activation of ABRE-Dependent Transcription in Arabidopsis

The Mediator complex controls transcription of most eukaryotic genes with individual subunits required for the control particular gene regulons in response to various perturbations. In this study, we reveal roles plant MED16, MED14, and MED2 regulating phytohormone abscisic acid (ABA) determine which cis elements are under their control. Using synthetic promoter reporters established an effective system testing relationships between specific cis- acting motifs protoplasts. Our results demonstrate that full transcriptional activation by ABA promoters containing both ABRE (ABA-responsive element) DRE (drought-responsive element). motif concatamers, showed ABA-responsive but not was dependent on these three subunits. Furthermore, were water loss from leaves played no role ABA-dependent growth inhibition, highlighting specificity functions. identify new subunits, provide a direct demonstration function highlight our experimental approach can be utilized regulators.