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Updated: Jul 27, 2025

Microscopy of Fission Yeast Sexual Lifecycle
Published on: March 9, 2016
Cell Fusion Promoting Factor Common to Homothallic and Heterothallic Mating Systems in Dictyostelium discoideum
Hideko Urushihara1, Tomoko Saigo1, Kaichiro Yanagisawa1
1Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305, Japan.
Abstract:
Cellular slime mould Dictyostelium discoideum propagates as single haploid cells and under certain environmental conditions enters into a sexual cycle called macrocyst formation. There are homothallic and heterothallic strains reported, the former being able to form macrocysts in clonal cell populations while the latter to do so only in the presence of opposite mating-type strains. Molecular basis for differential mating systems is an intersting subject totally unknown yet. In the present study, sexual cell interactions in AC4, a homothallic strain of D. discoideum, was studied in comparison with the heterothallic mating system. The conditoned medium of AC4 cells was found to promote the sexual cell fusion among themselves. In addition, it also enhanced the cell fusion between heterothallic strains. Furthermore, the conditioned medium obtained from the mated culture of heterothallic strains reported to induce the sexual cell fusion in the heterothallic strains (Saga and Yanagisawa, 1983) was found also to promote the cell fusion in AC4. These results suggest that common regulatory mechanisms operate for sexual cell fusion among different mating systems in D. discoideum.
Insights
Cellular slime mold Dictyostelium discoideum utilizes common regulatory mechanisms for sexual cell fusion. Conditioned media from both homothallic and heterothallic strains promote mating across different systems.
Area of Science:
- Cell Biology
- Genetics
- Mycology
Background:
- Dictyostelium discoideum exists as single haploid cells.
- Sexual reproduction occurs via macrocyst formation under specific conditions.
- Homothallic strains form macrocysts solitarily, while heterothallic strains require opposite mating types.
Purpose of the Study:
- To investigate the molecular basis of differential mating systems in Dictyostelium discoideum.
- To compare sexual cell interactions in the homothallic strain AC4 with heterothallic mating systems.
- To identify common regulatory mechanisms governing sexual cell fusion.
Main Methods:
- Studied sexual cell interactions in the homothallic Dictyostelium discoideum strain AC4.
- Compared interactions with known heterothallic mating systems.
- Analyzed the effects of conditioned media from different strains on cell fusion.
Main Results:
- Conditioned medium from AC4 cells promoted self-fusion and enhanced fusion between heterothallic strains.
- Conditioned medium from mated heterothallic strains also promoted cell fusion in AC4.
- These findings indicate shared regulatory pathways for sexual cell fusion.
Conclusions:
- Common regulatory mechanisms are involved in sexual cell fusion across different mating systems in Dictyostelium discoideum.
- The study provides insights into the molecular basis of mating system differentiation.
- Further research is warranted to elucidate these shared pathways.
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