G1/S transcription factors assemble in increasing numbers of discrete clusters through G1 phase.

Labe Black, Sylvain Tollis, Guo Fu, Jean-Bernard Fiche, Savanna Dorsey, Jing Cheng, Ghada Ghazal, Stephen Notley, Benjamin Crevier, Jeremy Bigness, Marcelo Nollmann, Mike Tyers, Catherine Ann Royer

The Journal of cell biology 2020 Sep 07

filter terms:

In budding yeast, the transcription factors SBF and MBF activate a large program of gene expression in late G1 phase that underlies commitment to cell division, termed Start. SBF/MBF are limiting with respect to target promoters in small G1 phase cells and accumulate as cells grow, raising the questions of how SBF/MBF are dynamically distributed across the G1/S regulon and how this impacts the Start transition. Super-resolution Photo-Activatable Localization Microscopy (PALM) mapping of the static positions of SBF/MBF subunits in fixed cells revealed each transcription factor was organized into discrete clusters containing approximately eight copies regardless of cell size and that the total number of clusters increased as cells grew through G1 phase. Stochastic modeling using reasonable biophysical parameters recapitulated growth-dependent SBF/MBF clustering and predicted TF dynamics that were confirmed in live cell PALM experiments. This spatio-temporal organization of SBF/MBF may help coordinate activation of G1/S regulon and the Start transition. © 2020 Black et al.

Citation

Labe Black, Sylvain Tollis, Guo Fu, Jean-Bernard Fiche, Savanna Dorsey, Jing Cheng, Ghada Ghazal, Stephen Notley, Benjamin Crevier, Jeremy Bigness, Marcelo Nollmann, Mike Tyers, Catherine Ann Royer. G1/S transcription factors assemble in increasing numbers of discrete clusters through G1 phase. The Journal of cell biology. 2020 Sep 07;219(9)