RT Journal Article
SR Electronic
T1 Altered Mediator dynamics during heat shock in budding yeast
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.08.25.267088
DO 10.1101/2020.08.25.267088
A1 Debasish Sarkar
A1 Z. Iris Zhu
A1 Emily Paul
A1 David Landsman
A1 Randall H. Morse
YR 2020
UL http://biorxiv.org/content/early/2020/08/26/2020.08.25.267088.abstract
AB The Mediator complex is central to transcription by RNA polymerase II (Pol II) in eukaryotes. In yeast, Mediator is recruited by activators via its tail module and then facilitates assembly of the pre-initiation complex (PIC), including Pol II, setting the stage for productive transcription. Mediator occupies proximal promoter regions only transiently prior to Pol II escape; interruption of the transcription cycle by inactivation or depletion of Kin28 inhibits Pol II escape and stabilizes Mediator occupancy at promoters. However, whether Mediator occupancy and dynamics differ for gene cohorts induced by stress or alternative growth conditions has not been examined on a genome-wide scale. Here we investigate Mediator occupancy following heat shock or CdCl2 induction, with or without depletion of Kin28. We find that Pol II occupancy exhibits similar dependence on Mediator under normal and heat shock conditions; however, Mediator occupancy does not increase upon Kin28 depletion at most genes active during heat shock, indicating altered dynamics. Furthermore, Mediator occupancy persists at genes repressed by heat shock or CdCl2 induction and exhibits peaks upstream of the proximal promoter whether or not Kin28 is depleted, suggesting that Mediator is recruited by activators but is unable to engage PIC components at these repressed targets. Finally, we show a reduced dependence on PIC components for Mediator occupancy at promoters after heat shock, further supporting an altered dynamics or stronger engagement with activators under these conditions.Competing Interest StatementThe authors have declared no competing interest.