Related Experiment Video

Updated: Jul 20, 2026

ACT1-CUP1 Assays Determine the Substrate-Specific Sensitivities of Spliceosomal Mutants in Budding Yeast
07:31

ACT1-CUP1 Assays Determine the Substrate-Specific Sensitivities of Spliceosomal Mutants in Budding Yeast

Published on: June 30, 2022

The classical srb4-138 mutant allele causes dissociation of yeast Mediator

Tomas Linder1, Xuefeng Zhu, Vera Baraznenok

  • 1Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Novum, SE-141 86 Stockholm, Sweden. tomas.linder@ki.se <tomas.linder@ki.se>

Biochemical and Biophysical Research Communications
|September 12, 2006
PubMed

Insights

The Mediator complex

Area of Science:

  • Molecular Biology
  • Biochemistry
  • Genetics

Background:

  • The Mediator complex is crucial for RNA polymerase II transcription.
  • Med17 subunit is essential for Mediator function and cell viability in yeast.
  • The srb4-138 mutant reveals the importance of Mediator but its molecular basis is unclear.

Purpose of the Study:

  • To investigate the molecular mechanism underlying the srb4-138 mutation's effect on the Mediator complex.
  • To understand how Mediator complex integrity affects RNA polymerase II transcription.

Main Methods:

  • Biochemical characterization of the Mediator complex from srb4-138 mutant cells.
  • Analysis of Mediator complex subunit interactions and promoter association.

Main Results:

  • The Mediator complex dissociates at the head/middle domain boundary in srb4-138 mutants, even at permissive temperatures.
  • Both head and middle domains can independently bind RNA polymerase.
  • At non-permissive temperatures, the head domain detaches from the promoter.

Conclusions:

  • The srb4-138 mutation destabilizes the Mediator complex, leading to transcription defects.
  • Mediator complex integrity is essential for stable promoter association and transcription initiation.
  • Dissociation of Mediator sub-complexes disrupts RNA polymerase II-dependent transcription.

More Related Videos

A Deep-sequencing-assisted, Spontaneous Suppressor Screen in the Fission Yeast Schizosaccharomyces pombe07:55

A Deep-sequencing-assisted, Spontaneous Suppressor Screen in the Fission Yeast Schizosaccharomyces pombe

Published on: March 7, 2019

Gene-targeted Random Mutagenesis to Select Heterochromatin-destabilizing Proteasome Mutants in Fission Yeast07:18

Gene-targeted Random Mutagenesis to Select Heterochromatin-destabilizing Proteasome Mutants in Fission Yeast

Published on: May 15, 2018

Related Concept Videos

Yeast Signaling01:28

Yeast Signaling

Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...
Conservative Site-specific Recombination and Phase Variation02:53

Conservative Site-specific Recombination and Phase Variation

Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...