Cell biology and genetics unit, zoological laboratory, university of leiden, kaiserstraat 63, 2311 gp leiden, the netherlands summary the differentiation inducing factor, dif, was previously shown to induce stalk cell differentiation in dictyostelium discoideum cells incubated as submerged monolayers. Involvement of a cellsurface glycoprotein in the cell. Developmentally regulated, carbohydratebinding protein in dictyostelium discoideum. By inducing the differentiation of isolated cells we hope to identify these signals. Saran s, nakao h, tasaka m, iida h, tsuji fi, nanjundiah v. On induction of cell differentiation by cyclic amp pulses. In dictyostelium amoebae, cell type differentiation, spatial patterning, and morphogenesis are controlled by a combination of cell autonomous mechanisms and intercellular signaling. Diffusible signal molecules controlling cell differentiation. We have identified genes that are expressed preferentially in either prestalk or prespore cells in dictyostelium. Its life cycle begins as spore released from a mature fruiting body sorocarp and then this sorocarp the spore hatches under warm and moist conditions to give rise. Pdf effects of polyunsaturated fatty acids on the growth.
Apr 01, 1979 most cells of strain v12 m2, when plated at high density with cyclic amp, differentiate into prespore 0301468 17900007s 01. When readers of this journal think about dictyostelium rarely, if at all, i suspectthey may conjure up dim memories either of college laboratory demonstrations involving cell aggregation and camp or of watching the cells develop into tiny fruiting bodies made of spores and stalks. Get a printable copy pdf file of the complete article 1. Analysis of this process using genetics and simple culture techniques is becoming a powerful way of investigating a number of conserved signal transduction processes.
During the first few hours of starvation, dictyostelium discoideum amoebae excrete a macromolecule, probably a glycoprotein, which stimulates cell differentiation to aggregation competence. Separation and properties of prestalk and prespore cells of dictyostelium discoideum. Yeasts and several invertebrate or vertebrate model systems are widely known for their contributions to our. These results suggest that cell differentiation could be brought about in normal development by the localized action of camp and dif1. A differentiation stimulating factor induces cell sensitivity to 3. Asf is able to bridge the initial block of differentiation in the latter mutant, such that developmen to t proceeds up. Several hours after the end of the growth phase, single cells of dictyostelium discoideum aggregate into a multicellular organism. Mar 01, 1982 the motion of cells in the aggregation phase of dictyostelium discoideum development is complex. Initial differentiation into randomly dis persed cells prestalk and prespore cells is clearly distinguishable in the aggregate. Regulation of cell differentiation and pattern formation in. Analysis of cell cycle progression during the development.
Pattern formation occurs in clumps of dictyostelium cells embedded in agar under a 100%. Integration of signaling networks that regulate dictyostelium. Postaggregation dictyostelium discoideum cells contain 3000 mrna species that are absent from preaggregation cells. Devreotes, 1 and pauline schaap 23 department of biological chemistry, the johns hopkins university school of medicine, baltimore, maryland 21287 usa. Dictyostelium is a genus of single and multicelled eukaryotic, phagotrophic bacterivores. Spalten, a protein containing gaproteinlike and pp2c. Periodic cell aggregation in suspensions of dictyostelium. Differentiation of these cells from uncommitted amoebae. Dictyostelium cellular slime mouldsocial amoebamyxamoeba solitary haploid amoeba. Pdf changes of plasma membrane proteins during prespore. Pdf inhibition of aggregation and differentiation of. The distribution of prestalk and prespore cells in mhc a. Firtel1 department of biology, center for molecular genetics, university of california, san diego ucsd. Regulation of dictyostelium discoideum mrnas specific.
Cell aggregation and differentiation in dictyostelium007 slideshare. In contrast, pulses applied at intervals of 2 min did not induce cell differentiation. Aggregation patterns and mechanisms of dictyostelium cells have been used as a model for these studies. Novel functions of ribosomal protein s6 in growth and. As aberrant fruiting bodies were made by ampka2 cells, we were interested in elucidating the role of ampka in regulat ing celltype differentiation figure 7. Combinatorial cellspecific regulation of gsk3 directs. Cell differentiation in dictyostelium discoideum sciencedirect. The aggregation patterns are formed through selforganization. On induction of cell differentiation by cyclic amp pulses in. Development of an autophagic system in differentiating cells.
Pulse chase experiments indicate a close correlation between cell cycle phase at the onset of development and differentiation fate. When a food source is available, dictyostelium cells exist as free. Materials and methods dictyostelium culture, development and differentiation dictyostelium wildtype and mutant cells were grown, developed on. Abstract in dictyostelium amoebae, cell type differentiation, spatial patterning, and morphogenesis are controlled by a combination of cell autonomous mechanisms and intercellular signaling. Cytoplasmic ph of dictyostelium discoideum amebae during. Get a printable copy pdf file of the complete article 6. Beug h, katz fe, gerisch g 1973 dynamics of antigenic membrane sites relating to cell aggregation in dictyostelium discoideum. Spalten, a protein containing gaproteinlike and pp2c domains, is essential for cell type differentiation in dictyostelium laurence aubry and richard a.
Ribosomalproteins ofthis organism are similar to those ofother higher eukaryotic cells 9 andthe system offers advantages notpossible inmosteukaryotes58. Cell differentiation in dictyostelium under submerged conditions. Aggregation in dictyostelium discoideum sciencedirect. Kay ct al cell differentiation in dictyostelium discoideum 5b9 culminotion i presstow, i stalk p cell i cni c fig. During dictyostelium development, cell communication coordinates the differentiation of 100,000 cells. No aggregation was observed after adding 480 units of partially purified inhibitor per plate along a line in front of the growth zone of aggr 504. The differentiation of autonomous cells starts roughly h 7 after the removal of food and saturates withi h. Pdf cell differentiation in dictyostelium under submerged conditions. Cell type differentiation and cell sorting result in a small. Pdf a celladhesion pathway regulates intercellular. Cytoplasmic ph of dictyostelium discoideum amebae during early development. Though they are protista and in no way fungal, they traditionally are known as slime molds. Ithasashortgenerationtime8hr, the cells develop synchronously and, within. Exogenous camp in the absence of sustained cell contact is sufficient to induce prestalkspecific gene expression.
When the cells starve, they aggregate to develop into a multicellular structure with only two main cell. Nevertheless prestalk cells can be clearly differentiated from aggregation. Control of cell differentiation by mitochondria, typically. Analysis of cell cycle progression during the development of. Chapter 6 cell aggregation and differentiation in dictyostelium. Combinatorial control of cell differentiation by camp and dif. The motion of cells in the aggregation phase of dictyostelium discoideum development is complex. Chemotactic signals induce cell differentiation in dictyostelium discoideum. Chemotactic signals induce cell differentiation in. Cell aggregation and differentiation in dictyostelium007 1. Nutrient depletion triggers the differentiation of dictyostelium cells through the transcriptional inactivation of some growth.
Receptors mediating cell aggregation in dictyostelium. We recorded cell behavior by time lapse microcinematography and extracted cell motion data from the film with our galatea computer system. Regulated protein degradation controls pka function and. The simple eukaryote dictyostelium discoideum is an excellent model system for studying questions such as cell type differentiation. Freeliving cells of dictyostelium discoideum aggregate to form a slugshaped cell mass and differentiate into prestalk and prespore cells. Adenylate cyclase activity oscillations as signals for. When cell contact and aggregate formation was prevented, differentiation never occurred within the single cells. Although cell differentiation can occur in the absence of cell contact, regulated cell cell adhesion is an important component of dictyostelium morphogenesis, and a third adhesion molecule, gp150, is required for multicellular development past the aggregation stage. Becomes multicellular when nutrition starvation occurs. Adenylate cyclase activity oscillations as signals for cell. The role of calcium in aggregation and development of. Regulated protein degradation controls pka function and cell.
In the heterothallic sexual cycle, amoebae aggregate in response to camp and sex pheromones, and two cells of opposite mating types fuse, and then begin consuming the other attracted cells. Because many eukaryotic signaling pathways have homologues in dictyostelium aubry and firtel, 1999, we examined the relationship between cell adhesion and communication in this model system. On the bases of genetic, serological, and physiological evidence, it has been suggested that two distinct cohesive systems operate. Cyclic amp is an inhibitor of stalk cell differentiation in dictyost. This unusual simplicity of control of their differentiation is, i think, the most interesting feature of the founder cells in this species. Repeated pulses of cyclic amp, applied at intervals of 5 min, efficiently induced differentiation in cells of agip 53, a morphogenetic mutant of dictyostelium discoideum, strain ax2. Pdf the level of sequestered calcium in vegetative amoebae. Extracellular camp is sufficient to restore developmental. During the last stage of dictyostelium development a motile, cylindrical slug transforms into an immotile, stalked fruiting body and the constituent cells change from amoebae to either refractile spores or vacuolated stalk cells. Dictyostelium, cell type differentiation, gene expression, psla summary identi. Specific cell cell contacts are essential for induction of gene expression during differentiation of dictyostelium discoideum february 1982 proceedings of the national academy of sciences 791. We show that the synthesis and stability of these regulated mrna sequences are affected by both cell cell contact and camp. Aggregation and cell surface receptors in cellular slime.
Pdf hitherto it has not been possible to obtain spore and stalk cell. Signal propagation during aggregation in the slime mould dictyostelium discoideum. Insigrid juselius symposium on cell interactions in cell differentiation,helsinki, academic press, in press. Mar 17, 2015 cell aggregation and differentiation in dictyostelium007 1. A differentiation stimulating factor induces cell sensitivity. Nutrient depletion triggers the differentiation of dictyostelium cells through the transcriptional inactivation of some growthphase genes, as well as through the transcriptional activation of essential genes required for the aggregation of the cells. Development of an autophagic system in differentiating. Cell aggregation and differentiation in dictyostelium. These features of development make dictyostelium an ideal organism to. Introduction during embryonic development, new cell types are created by the differentiation of uncommitted precursor.
Dictyostelium discoideum, dif1, camp, adenosine, ammonia, cell differentiation. Results indicate that activation of gsk3 by zak1 is required for cell polarization and migration. Cell aggregation and differentiation in dictyostelium007. Identification of two cell subpopulations before the aggregation stage ruth furukawa, john e. This led to the hypothesis that increased fluidity of the plasma membrane was responsible for the impaired cell cell interaction during differentiation 5.
Inhibition of aggregation and differentiation of dictyostelium discoideum by antibodies against adenosine 3. Initial cell type choice in dictyostelium eukaryotic cell. Many different signals can provoke the opening of calcium channels in the plasma. Pka is an important regulator of dictyostelium development. Prespore and prestalk cells in dictyostelium discoideum aggregates can be separated by density gradient centrifugation. Developmental decisions in dictyostelium discoideum. Pdf specific cellcell contacts are essential for induction. Studies of early stages of differentiation of the cellular slime mould. Pdf integration of signaling networks that regulate. As well as acting as a chemotactic factor1 cyclic amp stimulates cells of dictyostelium discoideum to differentiate after the end of growth into aggregation competent cells. Cell differentiation during the interphase between growth and aggregation is expressed in cell surface changes which include the following markers. To analyze this phenomenon the hydrolysis of cyclic amp between the pulses as well as the effect of the pulses on the. Interrelation of cell adhesion and differentiation in dictyostelium discoideum gunther gerisch maxplanckinstitut fur biochemie, d8033 martinsried, west germany introduction during the development of dictyostelium discoideum single cells aggregate to form a multicellular organism.
However, when starved, dictyostelium amoebae aggregate into a multicellular slug and finally form a fruiting body, whose spores germinate into amoebae, completing the cycle. Ammonia depletion and dif trigger stalk cell differentiation. Cells in sphase and early g2 differentiate preferentially into prestalk cells. The differentiation programme of dictyostelium discoideum is initiated by starvation. The differentiation of prespore cells is characterized. Much remains to be understood about how a group of cells break symmetry and differentiate into distinct cell types.
They are present in most terrestrial ecosystems as a normal and often abundant component of the soil microflora, and play an important role in the maintenance of balanced bacterial populations in soils. Amp, the chemoattractant in aggregation, and dif1, a novel chlorinated phenyl alkanone, which acts as a specific inducer of stalk cell differentiation. Combinatorial control of cell differentiation by camp and. Aggregation deficient mutants of dictyostelium 435 not identical with asf, although both are released from the cells at an early stage of differentiation. The dictyostelium cell cycle and its relationship to differentiation. Pdf the level of sequestered calcium in vegetative. The migrating slug contains three types of precursor cell. Autophagic vacuoles first appeared during formation of loose aggregates, coupled with the defecation of food vacuoles. The formation of the cell aggregate marks the beginning of the developmental phase in which cells differentiate into prestalk or prespore cells 8. Remarkably, transcripts of six of seven cdna clones, previously. However, a more detailed analysis of the effects of polyunsaturated fatty acids on growlth and differentiation 243 differentiation and aggregation of pufa supplemented cells has failed to.
Pka activity is controlled through regulation of the intracellular camp concentration. Changes in an autophagic system during differentiation of cells ofdictyostelium discoideum, nc4 were studied under light and electron microscopes, and it was demonstrated cytochemically that acid phosphatase was almost exclusively localized in food and autophagic vacuoles. Differentiation of mature stalk cells and spores occurs after about. Most cells of strain v12 m2, when plated at high density with cyclic amp, differentiate into prespore 0301468 17900007s 01. This chapter discusses experiments on the control of cell differentiation and pattern formation in a simple multicellular system. The individual amoebae composing of dictyostelium aggregate can differentiate into either stalk or spore cells according, it is believed, to the extracellular signals they receive. Biochemical markers indicate that these asfdonor mutants are blocked at a later step o celf l differentiation than an asfrequiring mutant. Combinatorial cellspecific regulation of gsk3 directs cell. Heterothallic mating has been best studied in dictyostelium discoideum and homothallic mating has been best studied in dictyostelium mucoroides strain dm7. Modeling the model organism dictyostelium discoideum. Eur j cell biol membrane proton pump inhibition and stalk cell differentia 58. Dictyostelium discoideum is a species of soildwelling amoeba belonging to the phylum amoebozoa, infraphylum mycetozoa. Gerischdynamics of antigenic membrane sites relating to cell aggregation in dictyostelium discoideum.
680 924 1586 519 481 1572 297 1251 535 1207 954 432 1119 1369 565 1110 1562 1067 362 1295 16 307 521 650 1454 18 101 841