Related Experiment Video
Updated: Jul 26, 2026

Dissection of Enhancer Function Using Multiplex CRISPR-based Enhancer Interference in Cell Lines
Published on: June 2, 2018
The Swi5 activator recruits the Mediator complex to the HO promoter without RNA polymerase II
L T Bhoite1, Y Yu, D J Stillman
1Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
Abstract:
Regulation of HO gene expression in the yeast Saccharomyces cerevisiae is intricately orchestrated by an assortment of gene-specific DNA-binding and non-DNA binding regulators. Binding of the early G1 transcription factor Swi5 to the distal URS1 element of the HO promoter initiates a cascade of events through recruitment of the Swi/Snf and SAGA complexes. In late G1, binding of transcription factor SBF to promoter proximal sequences results in the timely expression of HO. In this work we describe an important additional layer of complexity to the current model by identifying a connection between Swi5 and the Mediator/RNA polymerase II holoenzyme complex. We show that Swi5 recruits Mediator to HO by specific interaction with the Gal11 module of the Mediator complex. Importantly, binding of both the Gal11 and Srb4 mediator components to the upstream region of HO is independent of the SBF factor. Swi/Snf is required for Mediator binding, and genetic suppression experiments suggest that Swi/Snf and Mediator act in the same genetic pathway of HO activation. Experiments examining the kinetics of binding show that Mediator binds to HO promoter elements 1.5 kb upstream of the transcription start site in early G1, but this binding occurs without RNA Pol II. RNA Pol II does not bind to HO until late G1, when HO is actively transcribed, and binding occurs exclusively to the TATA region.
More Related Videos
09:21Saccharomyces cerevisiae Metabolic Labeling with 4-thiouracil and the Quantification of Newly Synthesized mRNA As a Proxy for RNA Polymerase II Activity
Published on: October 22, 2018
10:59Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
Published on: May 13, 2019
Related Concept Videos
RNA Polymerase II Accessory Proteins
Co-activators and Co-repressors
Eukaryotic Transcription Activators
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
Bacterial Transcription
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
RNA Polymerase II Accessory Proteins
Co-activators and Co-repressors