Fig. 2.

Immediate emergence of a stress-specific repertoire of active regulatory elements. a Schematic representation (upper panel) and a browser shot example (lower panel) of a transcribed distal regulatory element (dTRE) showing the characteristic pattern of short divergent transcription. The strand-specific measurement of Pol II density along the length of the dTRE is indicated with the red (plus strand) and blue (minus strand) boxes. The numbers of dTREs in K562 cells that occur prior to (NHS), upon acute heat shock (HS), or in both conditions are shown. b MA-plot showing dTREs with significantly up- or downregulated Pol II density across the length of the regulatory element. c Density of transcriptionally engaged Pol II at individual up- or downregulated dTREs. The dTREs are sorted by the increasing distance between the Pol II pause sites at the sense and the anti-sense strands, and the signal is centered to the middle coordinate between the pause sites