PT  - JOURNAL ARTICLE
AU  - Vu Q. Nguyen
AU  - Anand Ranjan
AU  - Sheng Liu
AU  - Xiaona Tang
AU  - Yick Hin Ling
AU  - Jan Wisniewski
AU  - Gaku Mizuguchi
AU  - Kai Yu Li
AU  - Vivian Jou
AU  - Qinsi Zheng
AU  - Luke D. Lavis
AU  - Timothée Lionnet
AU  - Carl Wu
TI  - Spatio-Temporal Coordination of Transcription Preinitiation Complex Assembly in Live Cells
AID  - 10.1101/2020.12.30.424853
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.12.30.424853
4099  - http://biorxiv.org/content/early/2020/12/30/2020.12.30.424853.short
4100  - http://biorxiv.org/content/early/2020/12/30/2020.12.30.424853.full
AB  - Transcription initiation by RNA polymerase II (Pol II) requires preinitiation complex (PIC) assembly at gene promoters. In the dynamic nucleus where thousands of promoters are broadly distributed in chromatin, it is unclear how ten individual components converge on any target to establish the PIC. Here, we use live-cell, single-molecule tracking in S. cerevisiae to document subdiffusive, constrained exploration of the nucleoplasm by PIC components and Mediator’s key functions in guiding this process. On chromatin, TBP, Mediator, and Pol II instruct assembly of a short-lived PIC, which occurs infrequently but efficiently at an average promoter where initiation-coupled disassembly may occur within a few seconds. Moreover, PIC exclusion by nucleosome encroachment underscores regulated promoter accessibility by chromatin remodeling. Thus, coordinated nuclear exploration and recruitment to accessible targets underlies dynamic PIC establishment in yeast. Collectively, our study provides a global spatio-temporal model for transcription initiation in live cells.Competing Interest StatementT.L. holds intellectual property rights related to Janelia Fluor dyes used in this publication. L.D.L. and Q.Z. are listed as inventors on patents and patent applications whose value might be affected by publication. The remaining authors declare no competing interests.