1. What is the role of mediator? Is it in prokaryotes or eukaryotes. 2. (TRUE OR FALSE) DNA- binding proteins that regulate initiation of gene transcription must partially open the DNA double helix in order to recognize the specific sequence they bind. Solution Mediators are multisubunit complexes present in eukaryotes, whose major role is to regulate or initiate transcription process. This is also called coactivator. The mediator complexes make interactions with transciption factors and RNA polymerase 2 and transfer signals in between..