“Hit-and-Run” transcription: de novo transcription initiated by a transient bZIP1 “hit” persists after the “run”

摘要: Dynamic transcriptional regulation is critical for an organism’s response to environmental signals and yet remains elusive capture. Such mediated by master transcription factors (TF) that control large gene regulatory networks. Recently, we described a dynamic mode of TF named “hit-and-run”. This model proposes can interact transiently with set targets, but the these transient targets continues after dissociation from target promoter. However, experimental evidence validating active TF-targets still lacking. Here, show TF-target interactions tracking de novo synthesis RNAs made in nuclear import. To do this, introduced affinity-labeled 4-thiouracil (4tU) nucleobase specifically isolate newly synthesized transcripts following conditional Thus, extended TARGET system (Transient Assay Reporting Genome-wide Effects Transcription factors) include 4tU-labeling this new technology TARGET-tU. Our proof-of-principle example Basic Leucine Zipper 1 (bZIP1), central integrator metabolic signaling plants. Using TARGET-tU, captured mRNAs bZIP1 import at time when no longer detectably bound its target. analysis transcripomics demonstrates may act as catalyst initiate complex (“hit”), which RNA polymerase without being promoter (“run”). findings provide proof supporting “hit-and-run” action. allows catalytically propagate rapid broad responses changes environment. functional read-out produced allowed us capture models genome-wide control.