show Abstracthide AbstractExtensive analysis if the means by which ERK affects transcription via enhancer regulation in mouse embryonic stem cells. This study combines analysis of mRNA, and nascent RNA dynamics and correlates this with changes in transcription factor, co-factor, and RNAPII binding and activity. Overall design: Mouse embryonic stem cells, stably expressing a cRAF-ErT2 expression cassette, were treated with 4OHT to activate ERK signalling via cRAF-ErT2 for either 2hrs, 8hrs, or 8hrs followed by a subsequent 2hr treatement with the MEK inhibitor PD0325901.