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Updated: Jul 27, 2025
Genetic Engineering of Dictyostelium discoideum Cells Based on Selection and Growth on Bacteria
Published on: January 25, 2019
Isolation and Characterization of Dictyostelium Mutants Defective in Sexual Cell Fusion: (Dictyostelium
Hideko Urushihara1, Kazuhiro Aiba1, Kaichiro Yanagisawa1
1University of Tsukuba, Institute of Biological Sciences, Tsukuba, Ibaraki 305, Japan.
Abstract:
Sexual cell fusion in the cellular slime mold Dictyostelium discoideum occurs between cells of opposite (heterothallic system) or same (homothallic system) mating types. It also requires certain environmental conditions such as darkness and abundance of water, and thus offers an interesting model system for analyzing mechanisms of cell recognition and of cellular response to environmental factors. We have been studying the mechanism of sexual cell fusion, using two heterothallic strains, NC4 and HM1 of D. discoideum. Two cell-surface glycoproteins, gp70 and gp138, have been identified as relevant molecules in the cell fusion of these strains. The former is specific to mat a cells (HM1) and the latter, common to both mat a and mat A (NC4). Involvement of cell-surface carbohydrates has also been suggested. However, the fuctions of the above fusion-related molecules are still elusive. In the present study, we isolated fusion-deficient mutants from a mutagenized mat A strain of D. discoideum to set up combined genetic and biochemical analyses. Among the three nonconditional mutants obtained, two were normal in the fruiting-body formation, asexual development, but one was aggregateless (agg- ). Further analysis of these mutants would provide detailed information on the mechanism of sexual cell fusion.
Insights
Researchers studied sexual cell fusion in Dictyostelium discoideum, identifying key cell-surface glycoproteins. They isolated mutants to further investigate the complex mechanisms of cell recognition and fusion.
Area of Science:
- Cell Biology
- Developmental Biology
- Microbiology
Background:
- Sexual cell fusion in Dictyostelium discoideum involves specific mating types and environmental cues.
- Cell-surface glycoproteins gp70 and gp138 are implicated in fusion, but their functions remain unclear.
- Understanding sexual cell fusion provides insights into cell recognition and environmental responses.
Purpose of the Study:
- To investigate the molecular mechanisms underlying sexual cell fusion in Dictyostelium discoideum.
- To identify novel genes and proteins involved in cell fusion through genetic and biochemical analyses.
- To elucidate the roles of cell-surface glycoproteins gp70 and gp138 in the fusion process.
Main Methods:
- Isolation of fusion-deficient mutants from a mutagenized mat A strain of Dictyostelium discoideum.
- Genetic analysis of isolated mutants, including assessment of fruiting-body formation and asexual development.
- Biochemical analyses to characterize the identified mutants and their associated molecules.
Main Results:
- Three nonconditional fusion-deficient mutants were successfully isolated.
- Two mutants exhibited normal fruiting-body formation and asexual development.
- One mutant displayed an aggregateless phenotype, suggesting a role in early developmental stages or cell-cell interactions.
Conclusions:
- The isolated mutants provide valuable tools for dissecting the genetic and molecular pathways of sexual cell fusion.
- Further analysis of these mutants will clarify the functions of previously identified fusion-related molecules.
- This study contributes to a deeper understanding of cell recognition and fusion mechanisms in Dictyostelium discoideum.
