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Isolation and Characterization of Dictyostelium Mutants Defective in Sexual Cell Fusion
Author(s) -
Urushihara Hideko,
Aiba Kazuhiro,
Yanagisawa Kaichiro
Publication year - 1991
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1991.00517.x
Subject(s) - dictyostelium discoideum , heterothallic , cell fusion , homothallism , mutant , biology , slime mold , mating type , cell , mutation , microbiology and biotechnology , sexual reproduction , fusion mechanism , genetics , gene , lipid bilayer fusion , virus
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.