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Current Opinion in Microbiology Dec 2002Dictyostelium genome sequencing predicts an unexpectedly large number of genes. Many are absent from yeast but present in animals and presumably support cellular... (Review)
Review
Dictyostelium genome sequencing predicts an unexpectedly large number of genes. Many are absent from yeast but present in animals and presumably support cellular abilities not found in yeast. Prominent amongst these abilities is chemotaxis, where great strides are being made in understanding how cells orient in a gradient and mobilise their cytoskeleton for movement. In multicellular development, a regulatory scheme for proportioning prespore and prestalk-O cells has emerged.
Topics: Animals; Cell Differentiation; Chemotaxis; Dictyostelium; Genome, Protozoan; Signal Transduction; Spores; Technology
PubMed: 12457700
DOI: 10.1016/s1369-5274(02)00375-2 -
Current Opinion in Cell Biology Dec 1992In Dictyostelium development, prestalk cells first differentiate at scattered positions in the aggregate and then sort out, probably by chemotaxis to cAMP. They may... (Review)
Review
In Dictyostelium development, prestalk cells first differentiate at scattered positions in the aggregate and then sort out, probably by chemotaxis to cAMP. They may regulate their proportions by selective depletion of the stalk cell inducer, DIF-1. Once sorted, prestalk cells form a DIF-1 sink, which can produce gradients of DIF-1 and its metabolites in the slug. Global movements of cells in the slug may be regulated by cAMP signals, as in aggregation. Terminal differentiation of stalk and spore cells requires activation of cAMP-dependent protein kinase, possibly brought about by ammonia depletion. Finally, a technique for insertional mutagenesis promises the ready isolation of developmental genes.
Topics: Animals; Antisense Elements (Genetics); Cell Differentiation; Cell Movement; Dictyostelium; Hexanones; Morphogenesis; Mutation; Protein Kinases
PubMed: 1485961
DOI: 10.1016/0955-0674(92)90121-r -
PloS One 2021The phospholipid phosphatidylserine (PS) is a key signaling molecule and binding partner for many intracellular proteins. PS is normally found on the inner surface of...
The phospholipid phosphatidylserine (PS) is a key signaling molecule and binding partner for many intracellular proteins. PS is normally found on the inner surface of the cell membrane, but PS can be flipped to the outer surface in a process called PS exposure. PS exposure is important in many cell functions, yet the mechanisms that control PS exposure have not been extensively studied. Copines (Cpn), found in most eukaryotic organisms, make up a family of calcium-dependent phospholipid binding proteins. In Dictyostelium, which has six copine genes, CpnA strongly binds to PS and translocates from the cytosol to the plasma membrane in response to a rise in calcium. Cells lacking the cpnA gene (cpnA-) have defects in adhesion, chemotaxis, membrane trafficking, and cytokinesis. In this study we used both flow cytometry and fluorescent microscopy to show that cpnA- cells have increased adhesion to beads and bacteria and that the increased adhesion was not due to changes in the actin cytoskeleton or cell surface proteins. We found that cpnA- cells bound higher amounts of Annexin V, a PS binding protein, than parental cells and showed that unlabeled Annexin V reduced the increased cell adhesion property of cpnA- cells. We also found that cpnA- cells were more sensitive to Polybia-MP1, which binds to external PS and induces cell lysis. Overall, this suggests that cpnA- cells have increased PS exposure and this property contributes to the increased cell adhesion of cpnA- cells. We conclude that CpnA has a role in the regulation of plasma membrane lipid composition and may act as a negative regulator of PS exposure.
Topics: Cell Adhesion; Cell Membrane; Dictyostelium; Mutation; Phosphatidylserines; Protozoan Proteins
PubMed: 34043641
DOI: 10.1371/journal.pone.0250710 -
Development, Growth & Differentiation May 2011Dictyostelium discoideum has been very useful for elucidating principles of development over the last 50 years, but a key attribute means there is a lot to be learned... (Review)
Review
Dictyostelium discoideum has been very useful for elucidating principles of development over the last 50 years, but a key attribute means there is a lot to be learned from a very different intellectual tradition: social evolution. Because Dictyostelium arrives at multicellularity by aggregation instead of through a single-cell bottleneck, the multicellular body could be made up of genetically distinct cells. If they are genetically distinct, natural selection will result in conflict over which cells become fertile spores and which become dead stalk cells. Evidence for this conflict includes unequal representation of two genetically different clones in spores of a chimera, the poison-like differentiation inducing factor (DIF) system that appears to involve some cells forcing others to become stalk, and reduced functionality in migrating chimeras. Understanding how selection operates on chimeras of genetically distinct clones is crucial for a comprehensive view of Dictyostelium multicellularity. In nature, Dictyostelium fruiting bodies are often clonal, or nearly so, meaning development will often be very cooperative. Relatedness levels tell us what benefits must be present for sociality to evolve. Therefore it is important to measure relatedness in nature, show that it has an impact on cooperation in the laboratory, and investigate genes that Dictyostelium uses to discriminate between relatives and non-relatives. Clearly, there is a promising future for research at the interface of development and social evolution in this fascinating group.
Topics: Biological Evolution; Dictyostelium; Genes, Protozoan; Selection, Genetic
PubMed: 21585362
DOI: 10.1111/j.1440-169X.2011.01272.x -
Annual Review of Genetics 1982
Review
Topics: Ammonia; Base Sequence; Crosses, Genetic; DNA; Dictyostelium; Genetic Linkage; Mutation; Recombination, Genetic; Transcription, Genetic
PubMed: 6760801
DOI: 10.1146/annurev.ge.16.120182.002125 -
Development (Cambridge, England) Jul 1989During the aggregation phase of their life cycle, Dictyostelium discoideum amoebae communicate with each other by traveling waves of cyclic AMP. These waves are... (Review)
Review
During the aggregation phase of their life cycle, Dictyostelium discoideum amoebae communicate with each other by traveling waves of cyclic AMP. These waves are generated by an interplay between random diffusion of cyclic AMP in the extracellular milieu and the signal-reception/signal/relaying capabilities of individual amoebae. Kinetic properties of the enzymes, transport proteins and cell-surface receptor proteins involved in the cyclic AMP signaling system have been painstakingly worked out over the past fifteen years in many laboratories. Recently Martiel & Goldbeter (1987) incorporated this biochemical information into a unified mathematical model of communication among Dictyostelium amoebae. Numerical simulations of the mathematical model, carried out by Tyson et al. (1989), agree in quantitative detail with experimental observations of cyclic AMP traveling waves in Dictyostelium cultures. Such mathematical modeling and numerical experimentation provide a necessary link between detailed studies of the molecular control mechanism and experimental observations of the intact developmental system.
Topics: Cyclic AMP; Dictyostelium; Receptors, Cyclic AMP; Signal Transduction
PubMed: 2557197
DOI: 10.1242/dev.106.3.421 -
Trends in Genetics : TIG Jan 2001Although the process of sequencing the Dictyostelium genome is not complete, it is already producing surprises, including an unexpectedly large number of Ras- and... (Review)
Review
Although the process of sequencing the Dictyostelium genome is not complete, it is already producing surprises, including an unexpectedly large number of Ras- and Rho-subfamily GTPases. Members of these families control a wide variety of cellular processes in eukaryotes, including proliferation, differentiation, cell motility and cell polarity. Comparison of small GTPases from Dictyostelium with those from higher eukaryotes provides an intriguing view of their cellular and evolutionary roles. In particular, although mammalian Ras proteins interact with several signalling pathways, the Dictyostelium pathways appear more linear, with each Ras apparently performing a specific cellular function.
Topics: Animals; Dictyostelium; GTP Phosphohydrolases
PubMed: 11163921
DOI: 10.1016/s0168-9525(00)02181-8 -
Protist Jun 2002
Review
Topics: Animals; Dictyostelium; Gene Expression Profiling; Gene Expression Regulation, Developmental; Mutation; Oligonucleotide Array Sequence Analysis
PubMed: 12125760
DOI: 10.1078/1434-4610-00087 -
Annual Review of Cell and Developmental... 1999In Dictyostelium amoebae, cell-type differentiation, spatial patterning, and morphogenesis are controlled by a combination of cell-autonomous mechanisms and... (Review)
Review
In Dictyostelium amoebae, cell-type differentiation, spatial patterning, and morphogenesis are controlled by a combination of cell-autonomous mechanisms and intercellular signaling. A chemotactic aggregation of approximately 10(5) cells leads to the formation of a multicellular organism. Cell-type differentiation and cell sorting result in a small number of defined cell types organized along an anteroposterior axis. Finally, a mature fruiting body is created by the terminal differentiation of stalk and spore cells. Analysis of the regulatory program demonstrates a role for several molecules, including GSK-3, signal transducers and activators of transcription (STAT) factors, and cAMP-dependent protein kinase (PKA), that control spatial patterning in metazoans. Unexpectedly, two component systems containing histidine kinases and response regulators also play essential roles in controlling Dictyostelium development. This review focuses on the role of cAMP, which functions intracellularly to mediate the activity of PKA, an essential component in aggregation, cell-type specification, and terminal differentiation. Cytoplasmic cAMP levels are controlled through both the regulated activation of adenylyl cyclases and the degradation by a phosphodiesterase containing a two-component system response regulator. Extracellular cAMP regulates G-protein-dependent and -independent pathways to control aggregation as well as the activity of GSK-3 and the transcription factors GBF and STATa during multicellular development. The integration of these pathways with others regulated by the morphogen DIF-1 to control cell fate decisions are discussed.
Topics: Animals; Dictyostelium; Signal Transduction
PubMed: 10611970
DOI: 10.1146/annurev.cellbio.15.1.469 -
Microbiological Reviews Mar 1996
Review
Topics: Animals; Dictyostelium; Gene Expression Regulation, Developmental
PubMed: 8852898
DOI: 10.1128/mr.60.1.135-150.1996