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Updated: Jul 7, 2026

Genetic Screen for Identification of Multicopy Suppressors in Schizosaccharomyces pombe
13:22

Genetic Screen for Identification of Multicopy Suppressors in Schizosaccharomyces pombe

Published on: September 13, 2022

Two conserved modules of Schizosaccharomyces pombe Mediator regulate distinct cellular pathways

Tomas Linder1, Nina N Rasmussen, Camilla O Samuelsen

  • 1Division of Metabolic Diseases, Karolinska Institutet, Novum, SE-141 86 Stockholm, Sweden. tlinder@cmp.ucsf.edu

Nucleic Acids Research
|March 4, 2008
PubMed

Insights

The Schizosaccharomyces pombe Mediator complex has distinct head and Cdk8 modules. Functional analysis reveals these modules control different cellular processes, including cell adhesion and separation, with conserved functions across yeast species.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • The Mediator complex is essential for RNA polymerase II transcription across eukaryotes.
  • In Schizosaccharomyces pombe, Mediator comprises a core complex (head and middle domains) and a Cdk8 regulatory subcomplex.
  • Understanding Mediator's functional modularity is key to deciphering gene regulation.

Purpose of the Study:

  • To functionally characterize the Schizosaccharomyces pombe Mediator complex.
  • To elucidate the molecular architecture and functional roles of Mediator submodules.
  • To compare Mediator function between Schizosaccharomyces pombe and Saccharomyces cerevisiae.

Main Methods:

  • Isolation and biochemical analysis of temperature-sensitive (ts) and deletion (Deltamed) alleles of Mediator subunits.
  • Phenotypic analysis of Mediator mutants, including cell flocculation and hyphal growth.
  • Gene expression profiling of Mediator mutants.

Main Results:

  • Identified S. pombe Med20 head subunit and isolated ts alleles of med17+.
  • Biochemical analysis revealed a stepwise molecular architecture of the Mediator head domain.
  • Mediator mutants were classified into two groups: Cdk8 module mutants (flocculation) and head module mutants (hyphal growth due to defective cell separation regulated by Ace2).

Conclusions:

  • The Schizosaccharomyces pombe Mediator exhibits functional modularity, with distinct roles for the Cdk8 and head modules.
  • Head module function is critical for cell separation, while Cdk8 module affects cell adhesion.
  • These functionally distinct modules and their conserved roles are conserved between S. pombe and S. cerevisiae.

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