A cell type-specific effect of calcium on pattern formation and differentiation in dictyostelium discoideum.
Spatial gradients of sequestered and free cellular calcium (Ca2+) exist in the slug of Dictyostelium discoideum (Maeda and Maeda, 1973; Tirlapur et al., 1991; Azhar et al., 1995; Cubitt et al., 1995). When we vary intracellular Ca2+ with the help of calcium buffers and the ionophore Br-A23187, there are striking effects on slug morphology, patterning and cell differentiation. In the presence of a calcium ionophore, high external Ca2+ levels lead to an increase of intracellular sequestered and free Ca2+, the formation of long slugs, a decrease in the fraction of genetically defined prespore cells and 'stalky' fruiting bodies. Conversely, a lowering of external Ca2+ levels results in a decrease of intracellular Ca2+, the formation of short slugs, an increase in the prespore fraction and 'spory' fruiting bodies. We infer that Ca2+ plays a significant morphogenetic role in D. discoideum development, by selectively promoting the prestalk pathway relative to the prespore pathway.
Baskar
R
R
Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore.
Chhabra
P
P
Mascarenhas
P
P
Nanjundiah
V
V
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation; D019070:Cell Lineage; D004396:Coloring Agents / Q000494:pharmacology; D004023:Dictyostelium / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D007700:Kinetics; D014170:Transformation, Genetic
D004396:Coloring Agents; D005456:Fluorescent Dyes; D007476:Ionophores; D000001:Calcimycin; D002118:Calcium