Extended Data Fig. 8

Short pulses of transient activation can suffice to produce a switch in transcriptional states. a, Messenger RNA levels of long-Hoxb in cells bearing the DD-dCas9-VPR construct and either lacking (wild-type, Ezh2 KO) or constitutively expressing (VPR ON, washout) sgRNAs specific to long-Hoxb, after induction for the indicated duration followed or not by 9-day washout. Values are normalized to the Ezh2 KO condition. b, Messenger RNA levels of indicated target genes in cells bearing the DD-dCas9-VPR construct and either lacking (wild-type, Ezh2 KO) or constitutively expressing (VPR OFF, ON, washout) sgRNAs specific to the target gene. Values within each experiment are normalized to the Ezh2 KO condition. Horizontal lines represent mean values. n.d., not detected. c, H3K27me3 levels measured by CUT&RUN over Nr2f1 in cells bearing the DD-dCas9-VPR construct, constitutively expressing sgRNAs specific to Nr2f1, and subjected to the indicated conditions. VPR washout condition follows a 6-day induction. Values within each experiment are normalized to the VPR OFF condition. d, Graphs depicting the levels of transcription (fraction of the maximum level reached for the indicated α, β values), and H3K27me3 levels, predicted at the conclusion of a simulation similar to that conducted for Fig. 3d. A transient pulse of transcriptional activation with α = αmax = 100 was simulated for the indicated number of cell cycles, followed by 20 cell cycles at the indicated α, β values, and levels of transcription and H3K27me3 at 20th cell cycle were plotted.