Ammonia hypersensitivity of slugger mutants of D. discoideum

1994 ◽  
Vol 107 (2) ◽  
pp. 701-708 ◽  
Author(s):  
K. Gee ◽  
F. Russell ◽  
J.D. Gross
Keyword(s):  
Dictyostelium Discoideum ◽  
Wild Type ◽  
Weak Base ◽  
Stages Of Development ◽  
Ammonia Inhibition ◽  
Complementation Groups ◽  
Tip Formation

The weak base ammonia inhibits aggregation and culmination of wild-type amoebae of Dictyostelium discoideum. Here we have examined its effect on a series of ‘slugger’ mutants previously assigned to 10 complementation groups, and so-called because they remain as slugs for extended periods. We show that the mutants accumulate normal levels of ammonia and hence may be abnormally susceptible to the ammonia they produce. In agreement with this we find that representatives of the slugger complementation groups are hypersensitive to ammonia inhibition at three clearly recognisable morphological stages of development: aggregation, tip formation and culmination. This finding suggests that a common ammonia-sensitive process underlies each of these developmental events.

NEW LOCI IN DICTYOSTELIUM DISCOIDEUM DETERMINING PIGMENT FORMATION AND GROWTH ON BACILLUS SUBTILIS

Genetics ◽  
1980 ◽  
Vol 96 (1) ◽  
pp. 115-123
Author(s):  
James H Morrissey ◽  
Steven Wheeler ◽  
William F Loomis
Keyword(s):  
Bacillus Subtilis ◽  
Dictyostelium Discoideum ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Linkage Groups ◽  
New Mutation ◽  
Pigment Formation ◽  
Complementation Groups ◽  
First Time

ABSTRACT Seventeen independently isolated pigmentless (white) mutations in Dictyostelium discoideum are all recessive and fall into three complementation groups identifying two new whi loci in addition to the previously characterized whiA locus. whiB and whiC map to linkage groups III and IV, respectively. In addition, it was discovered that our laboratory stock of NC4, the wild-type strain from which these mutants were derived, has spontaneously lost the ability to grow on Bacillus subtilis. This new mutation, bsgB500, maps to linkage group VII and is not allelic to bsgA. bsgB500 is the first spontaneously derived mutation in D. discoideum that can be used to select heterozygous diploids, and for the first time allows genetic analysis to be routinely performed on strains derived from an unmutagenized background.

scholarly journals Non-chemotactic Dictyostelium discoideum mutants with altered cGMP signal transduction.

1993 ◽  
Vol 123 (6) ◽  
pp. 1453-1462 ◽  
Author(s):  
H Kuwayama ◽  
S Ishida ◽  
P J Van Haastert
Keyword(s):  
Folic Acid ◽  
Dictyostelium Discoideum ◽  
Guanylyl Cyclase ◽  
Wild Type ◽  
Dose Dependency ◽  
Common Pathway ◽  
Surface Receptors ◽  
Complementation Groups ◽  
Mutant Cells ◽  
Guanylyl Cyclase Activity

Folic acid and cAMP are chemoattractants in Dictyostelium discoideum, which bind to different surface receptors. The signal is transduced from the receptors via different G proteins into a common pathway which includes guanylyl cyclase and acto-myosin. To investigate this common pathway, ten mutants which do not react chemotactically to both cAMP and folic acid were isolated with a simple new chemotactic assay. Genetic analysis shows that one of these mutants (KI-10) was dominant; the other nine mutants were recessive, and comprise nine complementation groups. In wild-type cells, the chemoattractants activate adenylyl cyclase, phospholipase C, and guanylyl cyclase in a transient manner. In mutant cells the formation of cAMP and IP3 were generally normal, whereas the cGMP response was altered in most of the ten mutants. Particularly, mutant KI-8 has strongly reduced basal guanylyl cyclase activity; the enzyme is present in mutant KI-10, but can not be activated by cAMP or folic acid. The cGMP response of five other mutants is altered in either magnitude, dose dependency, or kinetics. These observations suggest that the second messenger cGMP plays a key role in chemotaxis in Dictyostelium.

Investigation of a potential role for aldose reductase AlrA in tetrahydropteridine synthesis in Dictyostelium discoideum Ax2

Pteridines ◽  
2017 ◽  
Vol 28 (2) ◽  
pp. 97-103
Author(s):  
Hye-Lim Kim ◽  
Hyun-Chul Ryu ◽  
Young Shik Park
Keyword(s):  
Dictyostelium Discoideum ◽  
Aldose Reductase ◽  
Potential Role ◽  
Amino Acid Residues ◽  
Wild Type ◽  
High Sequence Identity ◽  
Physiological Conditions ◽  
Antioxidant Function ◽  
Cellular Extract ◽  
Sr Gene

AbstractDictyostelium discoideum Ax2 is well-known for the synthesis of d-threo-tetrahydrobiopterin (DH4) with a smaller amount of l-erythro-tetrahydrobiopterin (BH4). DH4 synthesis from 6-pyruvoyltetrahydropterin (PPH4) is catalyzed by aldose reductase (AR)-like protein and sepiapterin reductase (SR) via an intermediate 1′-oxo-2′-d-hydroxypropyl tetrahydropterin, which is non-enzymatically oxidized to d-sepiapterin in the absence of SR. However, l-sepiapterin was a dominant product in the reaction of a cellular extract of spr− disrupted in the SR gene. In order to investigate its potential role in tetrahydropteridine synthesis, the enzyme catalyzing l-sepiapterin synthesis from PPH4 was purified from spr−. Via mass spectrometry, the protein was identified to be encoded by alrA. AlrA consists of 297 amino acid residues sharing a high sequence identity with human AR. However, in the co-incubation assay, DH4 synthesis was not detected and, furthermore, the recombinant AlrA was observed to suppress BH4 synthesis by SR, which was known to prefer 1′-oxo-2′-d-hydroxypropyl tetrahydropterin to PPH4. Although intracellular DH4 level in alrA− was decreased to 60% of the wild type, it is presumed to result from the antioxidant function of DH4. Therefore, despite the structural and catalytic identities with human AR, AlrA seems to be involved in neither BH4, nor DH4 synthesis under normal physiological conditions.

scholarly journals A Putative Ariadne-Like Ubiquitin Ligase Is Required for Dictyostelium discoideum Development

2006 ◽  
Vol 5 (10) ◽  
pp. 1820-1825 ◽  
Author(s):  
Nathaniel Whitney ◽  
Lacey J. Pearson ◽  
Ryan Lunsford ◽  
Lisa McGill ◽  
Richard H. Gomer ◽  
...  
Keyword(s):  
Dictyostelium Discoideum ◽  
Ubiquitin Ligase ◽  
Fruiting Bodies ◽  
Wild Type ◽  
Cell Numbers

ABSTRACT The Dictyostelium rbrA gene encodes a putative Ariadne ubiquitin ligase. rbrA − cells form defective slugs that cannot phototax. Prestalk cell numbers are reduced in rbrA − slugs, and these prestalk cells do not localize to the tip of slugs. Chimeric slugs containing wild-type cells could phototax and form fruiting bodies.

scholarly journals Functional Promiscuity of Gene Regulation by Serpentine Receptors in Dictyostelium discoideum

1998 ◽  
Vol 18 (10) ◽  
pp. 5744-5749 ◽  
Author(s):  
Irene Verkerke-Van Wijk ◽  
Ji-Yun Kim ◽  
Raymond Brandt ◽  
Peter N. Devreotes ◽  
Pauline Schaap
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Dictyostelium Discoideum ◽  
Developmental Regulation ◽  
Mutant Cell ◽  
Gene Induction ◽  
Specific Gene ◽  
Wild Type ◽  
Animal Development ◽  
Camp Stimulation

ABSTRACT Serpentine receptors such as smoothened and frizzled play important roles in cell fate determination during animal development. InDictyostelium discoideum, four serpentine cyclic AMP (cAMP) receptors (cARs) regulate expression of multiple classes of developmental genes. To understand their function, it is essential to know whether each cAR is coupled to a specific gene regulatory pathway or whether specificity results from the different developmental regulation of individual cARs. To distinguish between these possibilities, we measured gene induction in car1 car3 double mutant cell lines that express equal levels of either cAR1, cAR2, or cAR3 under a constitutive promoter. We found that all cARs efficiently mediate both aggregative gene induction by cAMP pulses and induction of postaggregative and prespore genes by persistent cAMP stimulation. Two exceptions to this functional promiscuity were observed. (i) Only cAR1 can mediate adenosine inhibition of cAMP-induced prespore gene expression, a phenomenon that was found earlier in wild-type cells. cAR1’s mediation of adenosine inhibition suggests that cAR1 normally mediates prespore gene induction. (ii) Only cAR2 allows entry into the prestalk pathway. Prestalk gene expression is induced by differentiation-inducing factor (DIF) but only after cells have been prestimulated with cAMP. We found that DIF-induced prestalk gene expression is 10 times higher in constitutive cAR2 expressors than in constitutive cAR1 or cAR3 expressors (which still have endogenous cAR2), suggesting that cAR2 mediates induction of DIF competence. Since in wild-type slugs cAR2 is expressed only in anterior cells, this could explain the so far puzzling observations that prestalk cells differentiate at the anterior region but that DIF levels are actually higher at the posterior region. After the initial induction of DIF competence, cAMP becomes a repressor of prestalk gene expression. This function can again be mediated by cAR1, cAR2, and cAR3.

Multiple regulatory genes control expression of a gene family during development of Dictyostelium discoideum

1986 ◽  
Vol 6 (12) ◽  
pp. 4353-4361
Author(s):  
S Alexander ◽  
A M Cibulsky ◽  
S D Cuneo
Keyword(s):  
Gene Family ◽  
Dictyostelium Discoideum ◽  
Regulatory Genes ◽  
Developmental Expression ◽  
Developmentally Regulated ◽  
Suppressor Activity ◽  
Normal Expression ◽  
Mutant Strains ◽  
Complementation Groups ◽  
In Trans

Mutant strains of Dictyostelium discoideum carrying dis mutations fail to transcribe specifically the family of developmentally regulated discoidin lectin genes during morphogenesis. The phenotypes of these mutants strongly suggested that the mutations reside in regulatory genes. Using these mutant strains, we showed that multiple regulatory genes are required for the expression of the lectin structural genes and that these regulatory genes (the dis+ alleles) act in trans to regulate this gene family. These regulatory genes fall into two complementation groups (disA and disB) and map to linkage groups II and III, respectively. A further regulatory locus was defined by the identification of an unlinked supressor gene, drsA (discoidin restoring), which is epistatic to disB, but not disA, and results in the restoration of lectin expression in cells carrying the disB mutation. Mutant cells carrying the drsA allele express the discoidin lectin gene family during growth and development, in contrast to wild-type cells which express it only during development. Therefore, the suppressor activity of the drsA allele appears to function by making the expression of the discoidin lectins constitutive and no longer strictly developmentally regulated. The data indicate that normal expression of the discoidin lectins is dependent on the sequential action of the disB+, drsA+, and disA+ gene products. Thus, we described an interacting network of regulatory genes which in turn controls the developmental expression of a family of genes during the morphogenesis of D. discoideum.

scholarly journals Migration and bidirectional phototaxis in Dictyostelium discoideum slugs lacking the actin cross-linking 120 kDa gelation factor.

1997 ◽  
Vol 200 (24) ◽  
pp. 3213-3220 ◽  
Author(s):  
E Wallraff ◽  
H G Wallraff
Keyword(s):  
Dictyostelium Discoideum ◽  
Incident Light ◽  
Actin Binding ◽  
Cross Linking ◽  
Alternative Possibility ◽  
Wild Type ◽  
Oblique Angle ◽  
Mutant Strains ◽  
Cross Linker ◽  
Actin Capping

Three mutant strains of Dictyostelium discoideum, lacking different actin-binding proteins, were tested for behavioural deficits in the multicellular pseudoplasmodium (slug) stage. Two strains, defective in the production of either -actinin (an actin cross-linker) or severin (an actin capping and severing protein), did not show changes in slug behaviour. Slugs of the mutant lacking another actin cross-linker, the 120 kDa gelation factor (ABP-120), however, migrated shorter distances in darkness as well as in horizontally directed light. More remarkably, they migrated at an angle of approximately 45 degrees to the left or right of the incident light, whereas wild-type slugs migrated on fairly straight paths towards the light. We discuss the hypothesis that this bidirectional oblique-angle phototaxis is due to changes in the optical properties of the pseudoplasmodia. Normally, in wild-type slugs, a lens effect causes stronger stimulation on the side distal to the incident light. We propose that in the mutant the lens quality is reduced, so that at small angles between the slug axis and the rays of light the proximal side is stimulated more intensely. As a result, the intended symmetrical stimulation is achieved at a certain angle to the left or right of the incident light. We assume that the absence of ABP-120 alters the shape of the lens and/or enhances internal light scattering via degradation of intercellular coherence; however, intracellular attenuation of light remains an additional or alternative possibility.

scholarly journals Continuous in vivo infusion of interferon-gamma (IFN-γ) enhances engraftment of syngeneic wild-type cells in Fanca–/– and Fancg–/– mice

Blood ◽  
2006 ◽  
Vol 108 (13) ◽  
pp. 4283-4287 ◽  
Author(s):  
Yue Si ◽  
Samantha Ciccone ◽  
Feng-Chun Yang ◽  
Jin Yuan ◽  
Daisy Zeng ◽  
...  
Keyword(s):  
Stem Cells ◽  
Interferon Gamma ◽  
Cancer Susceptibility ◽  
Genetic Disorder ◽  
Wild Type ◽  
Regulatory Cytokine ◽  
Complementation Groups ◽  
Ifn Γ

Abstract Fanconi anemia (FA) is a heterogeneous genetic disorder characterized by bone marrow (BM) failure and cancer susceptibility. Identification of the cDNAs of FA complementation types allows the potential of using gene transfer technology to introduce functional cDNAs as transgenes into autologous stem cells and provide a cure for the BM failure in FA patients. However, strategies to enhance the mobilization, transduction, and engraftment of exogenous stem cells are required to optimize efficacy prior to widespread clinical use. Hypersensitivity of Fancc–/– cells to interferon-gamma (IFN-γ), a nongenotoxic immune-regulatory cytokine, enhances engraftment of syngeneic wild-type (WT) cells in Fancc–/– mice. However, whether this phenotype is of broad relevance in other FA complementation groups is unresolved. Here we show that primitive and mature myeloid progenitors in Fanca–/– and Fancg–/– mice are hypersensitive to IFN-γ and that in vivo infusion of IFN-γ at clinically relevant concentrations was sufficient to allow consistent long-term engraftment of isogenic WT repopulating stem cells. Given that FANCA, FANCC, and FANCG complementation groups account for more than 90% of all FA patients, these data provide evidence that IFN-γ conditioning may be a useful nongenotoxic strategy for myelopreparation in FA patients.

The stabilization of morphological field size during slime mold morphogenesis

Development ◽  
1978 ◽  
Vol 44 (1) ◽  
pp. 45-51
Author(s):  
Michael Peacock ◽  
David R. Soll
Keyword(s):  
Dictyostelium Discoideum ◽  
Aggregate Size ◽  
Slime Mold ◽  
Field Size ◽  
Cellular Slime Mold ◽  
Slime Mold Dictyostelium Discoideum ◽  
Cellular Slime ◽  
The Relationship ◽  
Tip Formation

The relationship between aggregate size and morphological field size has been investigated in the cellular slime mold Dictyostelium discoideum. Evidence is presented that aggregate size and field size exhibit different temperature sensitivities and that an aggregate can be induced to separate into several morphological fields by a decrease in temperature. In addition, evidence is presented that field size is stabilized at a point in time just prior to tip formation.

Action of a slowly hydrolysable cyclic AMP analogue on developing cells of Dictyostelium discoideum

1979 ◽  
Vol 35 (1) ◽  
pp. 321-338
Author(s):  
C. Rossier ◽  
G. Gerisch ◽  
D. Malchow
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Type Strain ◽  
Wild Type Strain ◽  
Agar Plate ◽  
Cell Aggregation ◽  
Fruiting Bodies ◽  
Wild Type ◽  
Camp Analogue ◽  
Order Of Magnitude

Adenosine 3′,5′-cyclic phosphorothioate (cAMP-S) is a cyclic AMP (cAMP) analogue which is only slowly hydrolysed by phosphodiesterases of Dictyostelium discoideum. The affinity of cAMP-S to cAMP receptors at the cell surface is only one order of magnitude lower than that of cAMP. cAMP-S can replace cAMP as a stimulant with respect to all receptor-mediated responses tested, including chemotaxis and the induction of cAMP pulses. cAMP-S does not affect growth of D. discoideum but it blocks cell aggregation at a uniform concentration of 5 × 10(−7) M in agar plate cultures of strain NC-4 as well as its axenically growing derivative, Ax-2. Another wild-type strain of D. discoideum, v-12, is able to aggregate on agar plates supplemented with 1 mM cAMP-S. The development of Polysphondylium pallidum and P. violaceum is also highly cAMP-S resistant. In Ax-2 both differentiation from the growth phase to the aggregation-competent stage and chemotaxis are cAMP-S sensitive, whereas in v-12 only chemotaxis is inhibited. v-12 can still form streams of cohering cells and fruiting bodies when chemotaxis is inhibited by cAMP-S. Whereas cAMP induces differentiation into stalk cells at concentrations of 10(−3) or 10(−4) M, cAMP-S has the same effect in strain v-12 at the much lower concentration of 10(−6) M.

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