The role of diffusible molecules in regulating the cellular differentiation of Dictyostelium discoideum

Development ◽  
1988 ◽  
Vol 103 (1) ◽  
pp. 1-16 ◽  
Author(s):  
J.G. Williams
Keyword(s):  
Developmental Biology ◽  
Cell Differentiation ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Cellular Differentiation ◽  
Prespore Cell ◽  
Additional Role ◽  
Acting In Concert ◽  
Morphogenetic Fields

A central problem in developmental biology is to understand how morphogenetic fields are created and how they act to direct regionalized cellular differentiation. This goal is being pursued in organisms as diverse as moulds, worms, flies, frogs and mice. Each organism has evolved its own solution to the challenge of multicellularity but there appear to be common underlying principles and, once pattern formation is fully understood in any system, some general truths seem certain to be revealed. As a non-obligate metazoan, Dictyostelium discoideum has proven a particularly tractable system in which to identify and characterize cellular morphogens. Cyclic AMP and ammonia stimulate prespore cell differentiation and ammonia plays an additional role in repressing terminal cellular differentiation. Differentiation Inducing Factor (DIF) acts to direct prestalk cell differentiation and adenosine may play a synergistic role in repressing prespore cell differentiation. This review summarizes the evidence for these interactions and describes a number of models which show how this small repertoire of diffusible molecules, acting in concert, may direct the formation of a differentiated structure.

Ammonia depletion and DIF trigger stalk cell intact Dictyostelium discoideum slugs

Development ◽  
1989 ◽  
Vol 105 (3) ◽  
pp. 569-574 ◽  
Author(s):  
M. Wang ◽  
P. Schaap
Keyword(s):  
Cell Differentiation ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Stalk Cell

The differentiation-inducing factor, DIF, was induce stalk cell differentiation in Dictyostelium incubated as submerged monolayers. We investigated the regulates the differentiation of stalk cells in the was found that in migrating or submerged slugs DIF cell differentiation, which is most likely due to the antagonist. Cyclic AMP and ammonia were earlier antagonists in vitro. We show here that ammonia, but an antagonist for DIF-induced stalk cell can induce stalk cell differentiation when ammonia are enzymically depleted. However, depletion of cAMP increase the efficacy of DIF. We propose that the cell differentiation during early culmination may be drop in ammonia levels inside the organism.

Periodic stimuli are more successful than randomly spaced ones for inducing development in Dictyostelium discoideum

1988 ◽  
Vol 8 (6) ◽  
pp. 571-577 ◽  
Author(s):  
Vidyanand Nanjundiah
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Vegetative State ◽  
Terminal Differentiation ◽  
Cellular Slime Mold ◽  
Slime Mold Dictyostelium Discoideum ◽  
Cellular Slime ◽  
Per Se ◽  
Stimulation Of

Aggregation in the cellular slime mold Dictyostelium discoideum is due to chemotaxis. The chemoattractant, cyclic AMP, is synthesised and released periodically by the cells. Externally applied periodic pulses of cyclic AMP can also induce differentiation in this organism. The present work examines the role of periodicity per se in cyclic AMP-mediated stimulation of cell differentiation. For this purpose we use Agip53, a Dictyostelium mutant which does not develop beyond the vegetative state but can be made to aggregate and differentiate by reiterated applications of cyclic AMP. Importantly, Agip53 cells do not make or release any cyclic AMP themselves even in response to an increase in extracellular cyclic AMP. A comparison of the relative efficiencies of periodic and aperiodic stimulation shows that whereas the two patterns of stimulation are equally effective in inducing the formation of EDTA-stable cell contacts, periodic stimuli are significantly superior for inducing terminal differentiation. This suggests that there must be molecular pathways which can only function when stimulation occurs at regular intervals.

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