Unique nascent transcriptomes define naïve, primed and paused embryonic pluripotent states.

Unique transcriptomes define naïve, primed and paused embryonic pluripotent states. Here we perform calibrated transient transcription sequencing (TT-seq) to de novo define and quantify coding and non-coding transcription units (TUs) in different pluripotent states. We observe a global reduction of RNA synthesis, total RNA amount and turnover rates in ground state (2i) and paused pluripotency (mTORi). We demonstrate that elongation speed can be reliably estimated from TT-seq nascent RNA and RNA Polymerase II occupancy levels, and observe a transcriptome-wide attenuation of elongation speeds in these two inhibitor-induced states. Comparing closely related transcriptional states with different elongation speeds, we also discover a relationship between elongation speed and termination read-through distance. Our analysis suggests that steady-state transcriptomes in mouse ESC cells are controlled predominantly on the level of RNA synthesis and signaling pathways governing different pluripotent states directly control key parameters of transcription. TT-seq on mESC pluripotent states: SL, 2i, and mTORi. With both label RNA (LRNA) and fragmented total RNA (FRNA).