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Updated: May 9, 2026

Microscopy of Fission Yeast Sexual Lifecycle
07:47

Microscopy of Fission Yeast Sexual Lifecycle

Published on: March 9, 2016

Distal and proximal actions of peptide pheromone M-factor control different conjugation steps in fission yeast

Taisuke Seike1, Taro Nakamura, Chikashi Shimoda

  • 1Department of Biology, Graduate School of Science, Osaka City University, Osaka, Japan. saysay@sci.osaka-cu.ac.jp

Plos One
|July 23, 2013
PubMed

Insights

Mating in yeast requires M-factor pheromone. Low concentrations promote initial cell adhesion via Map4, while proximity-based signaling is crucial for cell fusion.

Area of Science:

  • Cell Biology
  • Microbiology
  • Genetics

Background:

  • Haploid cell conjugation in Schizosaccharomyces pombe relies on P-type (P-cells) and M-type (M-cells) interactions.
  • M-factor, a peptide pheromone produced by M-cells, is recognized by P-cell receptors, mediating mating.
  • M-factor-less mutants exhibit sterility and lack sexual agglutination in liquid culture.

Purpose of the Study:

  • To investigate the distinct roles of M-factor in initiating cell-cell adhesion and facilitating cell fusion during yeast mating.
  • To differentiate between 'distal pheromone action' and 'proximal pheromone action' in Schizosaccharomyces pombe conjugation.

Main Methods:

  • Utilized an M-factor-less mutant of Schizosaccharomyces pombe.
  • Administered exogenous synthetic M-factor to assess recovery of mating phenotypes.
  • Analyzed cell aggregation and conjugation in mixed cultures of wild-type and mutant cells.
  • Observed polarized growth kinetics following cell contact.

Main Results:

  • Exogenous M-factor restored sexual agglutination and Map4 expression in the mutant, indicating initial adhesion.
  • Cell fusion remained defective in the M-factor-less mutant even with exogenous M-factor.
  • M-factor-less cells were incorporated into aggregates formed by wild-type cells, but preferential conjugation occurred with M-factor-secreting M-cells.
  • Polarized growth initiated at the contact interface between opposite mating-type cells.

Conclusions:

  • M-factor acts at low concentrations to induce adhesin expression (Map4), mediating 'distal pheromone action' for initial cell adhesion.
  • Directly secreted M-factor in proximity to adhered P-cells is essential for subsequent cell fusion, representing 'proximal pheromone action'.
  • These findings elucidate a two-step pheromone signaling mechanism crucial for successful yeast mating.

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