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Updated: May 3, 2026
Microscopy of Fission Yeast Sexual Lifecycle
Published on: March 9, 2016
Membrane organization and cell fusion during mating in fission yeast requires multipass membrane protein Prm1
M-Ángeles Curto1, Mohammad Reza Sharifmoghadam, Eduardo Calpena
1Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, 37007 Salamanca, Spain.
Abstract:
The involvement of Schizosaccharomyces pombe prm1(+) in cell fusion during mating and its relationship with other genes required for this process have been addressed. S. pombe prm1Δ mutant exhibits an almost complete blockade in cell fusion and an abnormal distribution of the plasma membrane and cell wall in the area of cell-cell interaction. The distribution of cellular envelopes is similar to that described for mutants devoid of the Fig1-related claudin-like Dni proteins; however, prm1(+) and the dni(+) genes act in different subpathways. Time-lapse analyses show that in the wild-type S. pombe strain, the distribution of phosphatidylserine in the cytoplasmic leaflet of the plasma membrane undergoes some modification before an opening is observed in the cross wall at the cell-cell contact region. In the prm1Δ mutant, this membrane modification does not take place, and the cross wall between the mating partners is not extensively degraded; plasma membrane forms invaginations and fingers that sometimes collapse/retract and that are sometimes strengthened by the synthesis of cell-wall material. Neither prm1Δ nor prm1Δ dniΔ zygotes lyse after cell-cell contact in medium containing and lacking calcium. Response to drugs that inhibit lipid synthesis or interfere with lipids is different in wild-type, prm1Δ, and dni1Δ strains, suggesting that membrane structure/organization/dynamics is different in all these strains and that Prm1p and the Dni proteins exert some functions required to guarantee correct membrane organization that are critical for cell fusion.
Insights
The Schizosaccharomyces pombe prm1 gene is crucial for cell fusion during mating. Its absence blocks fusion and alters cell envelope organization, highlighting Prm1p
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Cell fusion is a fundamental biological process essential for reproduction and development in many organisms.
- The fission yeast Schizosaccharomyces pombe serves as a model organism for studying conserved mechanisms of cell fusion.
- Previous studies identified genes involved in S. pombe mating, but the precise roles of some, like prm1(+), remained unclear.
Purpose of the Study:
- To investigate the function of the Schizosaccharomyces pombe prm1(+) gene in the process of cell fusion during mating.
- To elucidate the relationship between prm1(+) and other genes, such as Dni proteins, involved in cell fusion.
- To understand the role of Prm1p in regulating membrane organization and dynamics during cell-cell contact.
Main Methods:
- Construction and phenotypic analysis of S. pombe prm1 deletion mutants (prm1Δ).
- Time-lapse microscopy to observe cell fusion dynamics in wild-type and mutant strains.
- Analysis of plasma membrane and cell wall distribution during mating.
- Assessment of zygote viability and response to calcium and lipid-modulating drugs.
Main Results:
- prm1Δ mutants showed a near-complete blockade in cell fusion with abnormal plasma membrane and cell wall distribution at the contact site.
- Time-lapse analysis revealed that Prm1p is required for proper phosphatidylserine distribution and cross-wall degradation before fusion.
- Mutants exhibited altered membrane dynamics, including invaginations and finger-like projections, and differential responses to lipid synthesis inhibitors.
Conclusions:
- The Schizosaccharomyces pombe prm1(+) gene plays a critical role in regulating membrane organization and dynamics essential for successful cell fusion.
- Prm1p acts in a distinct subpathway from Dni proteins, although both are necessary for proper membrane organization during mating.
- These findings underscore the importance of precise membrane remodeling for cell fusion and identify Prm1p as a key regulator.
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