Functional analysis of Mediator subunits involved in heat stress response

Mechanism of heat stress response in plants has been studied focusing on the function of transcription factors (TFs). Generally, TFs recruit coactivators, such as Mediator, to assemble the transcriptional machinery. However, despite the close relationship with TFs, it is largely unclear how coactivators are involved in transcriptional regulation under heat stress conditions. We found that mutants of MED14 and MED17 show severe thermo-sensitive phenotype. To reveal the effect of these mutations, we performed RNA-seq analysis with Col, med14, and med17 under normal and heat stress (37°C for 1 h) conditions. This analysis revealed large difference in Mediator-dependency among genes, in particular, between high-dependency of TF genes and low-dependency of HSPs.