Chloroquine inhibits cell fusion during sexual development in Dictyostelium discoideum

1987 ◽  
Vol 33 (12) ◽  
pp. 1125-1129 ◽  
Author(s):  
Jiji Rivera ◽  
Danton H. O'Day
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Cell Morphology ◽  
Sexual Development ◽  
Protease Activity ◽  
Current Knowledge ◽  
Dependent Manner ◽  
Receptor Recycling ◽  
Sexual Cell ◽  
Dose Dependent

Chloroquine inhibits sexual cell fusion and macrocyst formation in heterothallic Dictyostelium discoideum in a dose-dependent manner. As judged by cell morphology, the effect of chloroquine is not due to nonspecific toxicity, and normal macrocyst development ensues upon the removal of the drug. The mode of action of chloroquine on both receptor recycling and protease activity is discussed in terms of current knowledge of sexual cell fusion in D. discoideum.

The role of intracellular Ca2+ during early sexual development in Dictyostelium discoideum: effects of LaCl3, LaCl3, Ins(1,4,5)P3, TMB-8, chlortetracycline and A23187 on cell fusion

1988 ◽  
Vol 90 (3) ◽  
pp. 465-473 ◽  
Author(s):  
MICHAEL A. LYDAN ◽  
DANTON H. O'DAY
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Calcium Release ◽  
Cytosolic Calcium ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Dose Dependent ◽  
Extracellular Environment ◽  
Internal Calcium

The agents LaCl3, Ins(1,4,5)P3, TMB-8, chlortetracycline (CTC) and A23187 were used to study the requirement for internal calcium mobilization during gamete cell fusion in Dictyostelium discoideum. The inhibition of the influx of calcium (LaCl3) prevented cell fusion in a dose-dependent manner. At the intracellular level, Ins(1,4,5)P3, an endogenous regulator of calcium release from intracellular stores, stimulated cell fusion within one hour following its addition. Treatment with agents that prevent the release of calcium from intracellular stores (TMB-8, CTC) also inhibited cell fusion in a dose-dependent manner. However, the non-specific augmentation of cytosolic calcium levels through the use of the ionophore A23187 inhibited cell fusion, and the amount inhibition was directly related to the drug concentration. Studies on cell morphology and growth plus results from reversibility experiments involving the ability to form macrocysts reveal that these effects are not due to non-specific drug toxicity. In total, these results suggest that the mobilization of calcium both from the extracellular environment and from intracellular stores important and is probably regulated during gamete cell fusion in D. discoideum.

Zygote giant cell differentiation in Dictyostelium discoideum: biochemical markers of specific stages of sexual development

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1200-1208 ◽  
Author(s):  
Darren D. Browning ◽  
Keith E. Lewis ◽  
Danton H. O'Day
Keyword(s):  
Alkaline Phosphatase ◽  
Cell Differentiation ◽  
Giant Cell ◽  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Sexual Development ◽  
Giant Cells ◽  
Second Phase ◽  
Developmental Phase ◽  
Calcium Dependent

Sexual development in Dictyostelium discoideum has many unique features making it an attractive eukaryotic model system for the study of biomembrane fusion and intercellular communication. The work presented here provides primary biochemical evidence for two distinct phases during early sexual development that appear to be defined by calcium-dependent gamete cell fusion. In addition, we introduce a novel procedure for the enrichment of zygote giant cells and use this method to define certain wheat-germ agglutinin binding glycoproteins which are specifically located in zygote giant cells and others which are markers for surrounding amoebae in the second phase of development. In addition, a G protein which is present in high amounts early in development is unique to giant cells in the second phase, suggesting a role in phagocytosis. Finally, alkaline phosphatase activity was found to mark the first phase of sexual development, suggesting a role in cell fusion. This contrasts with the patterns of α-mannosidase and β-glucosidase activity that increase late in the second developmental phase, where they likely function in endocyte digestion during the cytophagic period. The developmental significance of these findings is discussed.Key words: zygote giant cell differentiation, Ca2+, glycoproteins, GTP-binding proteins, alkaline phosphatase, glycosidase, cell fusion.

Antisense RNA inactivation of gp138 gene expression results in repression of sexual cell fusion in Dictyostelium discoideum

1993 ◽  
Vol 106 (3) ◽  
pp. 785-788
Author(s):  
H. Fang ◽  
K. Aiba ◽  
M. Higa ◽  
H. Urushihara ◽  
K. Yanagisawa
Keyword(s):  
Gene Expression ◽  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Antisense Rna ◽  
Transformed Cells ◽  
Fusion Activity ◽  
Sexual Cell ◽  
Genes Encoding

A glycoprotein, gp138, is implicated in the sexual cell fusion of Dictyostelium discoideum. We previously cloned and sequenced the two genes encoding the gp138 protein, GP138A and GP138B (Fang et al. (1993) Dev. Biol. 156, 201–208). Here, we have constructed a vector producing antisense RNA for the gp138 genes and have transformed the vector into Dictyostelium cells. The transformed cells showed a reduction in the amounts of gp138 mRNA and protein and their sexual cell fusion activity was considerably repressed.

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