1
|
Siu CH, Sriskanthadevan S, Wang J, Hou L, Chen G, Xu X, Thomson A, Yang C. Regulation of spatiotemporal expression of cell-cell adhesion molecules during development of Dictyostelium discoideum. Dev Growth Differ 2011; 53:518-27. [DOI: 10.1111/j.1440-169x.2011.01267.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
2
|
Beshay U, Friehs K, Flaschel E. Growth of myxamoebae of the cellular slime mold Dictyostelium discoideum in suspension and immobilized form on living bacteria. Process Biochem 2008. [DOI: 10.1016/j.procbio.2008.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
3
|
Salger K, Wetterauer B. Aberrant folate response and premature development in a mutant of Dictyostelium discoideum. Differentiation 2008. [DOI: 10.1111/j.1432-0436.2000.660406.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
4
|
Zhukovskaya NV, Fukuzawa M, Yamada Y, Araki T, Williams JG. The Dictyostelium bZIP transcription factor DimB regulates prestalk-specific gene expression. Development 2006; 133:439-48. [PMID: 16396914 DOI: 10.1242/dev.02190] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ecmA gene is specifically expressed in prestalk cells and its transcription is induced by the chlorinated hexaphenone DIF-1. We have purified a novel bZIP transcription factor, DimB, by affinity chromatography on two spatially separated ecmA promoter fragments. Mutagenesis of the cap-site proximal DimB-binding site (the -510 site) greatly decreases ecmA expression in the pstO cells, which comprise the rear half of the prestalk zone, and also in the Anterior-Like Cells, which lie scattered throughout the prespore region. However, DimB is not essential for normal expression of the ecmA gene, instead it spatially limits its expression; ecmA is relatively highly expressed in the subset of prestalk cells that coats the prestalk zone, but in slugs of a DimB-null strain, ecmA is highly expressed throughout the prestalk zone. Because the -510 site is required for correct ecmA expression, we posit a separate activator protein that competes with DimB for binding to the -510 site. DimB rapidly accumulates in the nucleus when cells are exposed to DIF-1, and ChIP analysis shows that, in the presence of extracellular cAMP, DIF-1 causes DimB to associate with the ecmA promoter in vivo. Thus, DIF-1 regulates DimB activity to generate a gradient of ecmA expression in the prestalk zone of the slug.
Collapse
|
5
|
Maeda Y. Regulation of growth and differentiation in Dictyostelium. INTERNATIONAL REVIEW OF CYTOLOGY 2005; 244:287-332. [PMID: 16157183 DOI: 10.1016/s0074-7696(05)44007-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In general, growth and differentiation are mutually exclusive, but they are cooperatively regulated during the course of development. Thus, the process of a cell's transition from growth to differentiation is of general importance not only for the development of organisms but also for the initiation of malignant transformation, in which this process is reversed. The cellular slime mold Dictyostelium, a wonderful model organism, grows and multiplies as long as nutrients are supplied, and its differentiation is triggered by starvation. A strict checkpoint (growth/differentiation transition or GDT point), from which cells start differentiating in response to starvation, has been specified in the cell cycle of D. discoideum Ax-2 cells. Accordingly, integration of GDT point-specific events with starvation-induced events is needed to understand the mechanism regulating GDTs. A variety of intercellular and intracellular signals are involved positively or negatively in the initiation of differentiation, making a series of cross-talks. As was expected from the presence of GDT points, the cell's positioning in cell masses and subsequent cell-type choices occur depending on the cell's phase in the cell cycle at the onset of starvation. Since novel and somewhat unexpected multiple functions of mitochondria in cell movement, differentiation, and pattern formation have been well realized in Dictyostelium cells, they are reviewed in this article.
Collapse
Affiliation(s)
- Yasuo Maeda
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan
| |
Collapse
|
6
|
Zhukovskaya NV, Fukuzawa M, Tsujioka M, Jermyn KA, Kawata T, Abe T, Zvelebil M, Williams JG. Dd-STATb, a Dictyostelium STAT protein with a highly aberrant SH2 domain, functions as a regulator of gene expression during growth and early development. Development 2004; 131:447-58. [PMID: 14701681 DOI: 10.1242/dev.00927] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Dictyostelium, the only known non-metazoan organism to employ SH2 domain:phosphotyrosine signaling, possesses STATs (signal transducers and activators of transcription) and protein kinases with orthodox SH2 domains. Here, however, we describe a novel Dictyostelium STAT containing a remarkably divergent SH2 domain. Dd-STATb displays a 15 amino acid insertion in its SH2 domain and the conserved and essential arginine residue, which interacts with phosphotyrosine in all other known SH2 domains, is substituted by leucine. Despite these abnormalities, Dd-STATb is biologically functional. It has a subtle role in growth, so that Dd-STATb-null cells are gradually lost from the population when they are co-cultured with parental cells, and microarray analysis identified several genes that are either underexpressed or overexpressed in the Dd-STATb null strain. The best characterised of these,discoidin 1, is a marker of the growth-development transition and it is overexpressed during growth and early development of Dd-STATb null cells. Dimerisation of STAT proteins occurs by mutual SH2 domain:phosphotyrosine interactions and dimerisation triggers STAT nuclear accumulation. Despite its aberrant SH2 domain, the Dd-STATb protein sediments at the size expected for a homodimer and it is constitutively enriched in the nucleus. Moreover, these properties are retained when the predicted site of tyrosine phosphorylation is substituted by phenylalanine. These observations suggest a non-canonical mode of activation of Dd-STATb that does not rely on orthodox SH2 domain:phosphotyrosine interactions.
Collapse
Affiliation(s)
- Natasha V Zhukovskaya
- School of Life Sciences, University of Dundee, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, UK
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Stephan M, Beshay U, Friehs K, Flaschel E. Influence of medium composition on growth behaviour of Dictyostelium discoideum for cultivation on axenic media. Process Biochem 2003. [DOI: 10.1016/s0032-9592(03)00085-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
8
|
Beshay U, Friehs K, Azzam AEM, Flaschel E. Cultivation of Dictyostelium discoideum in immobilized form by colonization of porous supports. Process Biochem 2003. [DOI: 10.1016/s0032-9592(03)00042-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
9
|
Takaoka N, Fukuzawa M, Kato A, Saito T, Ochiai H. Element analysis of the Polysphondylium pallidum gp64 promoter. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1574:304-10. [PMID: 11997096 DOI: 10.1016/s0167-4781(02)00227-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
gp64 mRNA in Polysphondylium pallidum is expressed extensively during vegetative growth, and begins to rapidly decrease at the onset of development. To examine this unique regulation, 5' deletion analysis of the gp64 promoter was undertaken, and two growth-phase activated elements have been found: a food-dependent, upstream regulatory region (FUR, -222 to -170) and a vegetatively activated, downstream region (VAD, -110 to -63). Here we concentrate our analysis on an A1 and A2 sequences in the FUR region: A1 consists of a GATTTTTTTA sequence called a corresponding sequence and A2 consists of the direct repeat TTTGTTGTG. The cells carrying a combined construct of A1 and A2 acted synergistically in a reporter activity. A point mutation analysis in A1 indicates that a G residue is required for the activation of A1. From analyses of promoter regulation in a liquid or a solid medium, the promoter activity of the cells fed on bacteria in A-medium (axenic medium for Polysphondylium) or grown in A-medium alone was only one fourth of that of the cells fed on bacteria. By the gel retardation, we detected a protein bound to the A1 sequence.
Collapse
Affiliation(s)
- Naohisa Takaoka
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, 060-0810, Sapporo, Japan
| | | | | | | | | |
Collapse
|
10
|
Zeng C, Anjard C, Primpke G, Wetterauer B, Wille S, Nellen W. Interaction of gdt1 and protein kinase A (PKA) in the growth-differentiation-transition in Dictyostelium. Differentiation 2001; 67:25-32. [PMID: 11270120 DOI: 10.1046/j.1432-0436.2001.067001025.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The gdt1 gene is a negative regulator of the growth-differentiation-transition (GDT) in Dictyostelium. gdt1- cells express the GDT marker discoidin earlier and at higher levels and prematurely enter the differentiation pathway. Protein kinase A is a positive regulator of the GDT and is required for multicellular development. Disruption of the PKA catalytic subunit or overexpression of a constitutively active mutant of the regulatory subunit results in cells which do not form multicellular aggregates and which show strongly reduced levels of discoidin. We have created PKA-/gdt1- double mutants and show that these display high levels of discoidin expression but no aggregation, suggesting that gdt1 may be a downstream target of PKA in a branched signaling cascade initiating differentiation. Data obtained with the PKA inhibitor H89 support these result: in wild type cells H89 inhibits discoidin expression while in gdt1- mutants there is no obvious effect. However, since PKA-/gdt1- cells display less discoidin expression than the single gdt1 mutant, we propose that PKA and gdt1 are in two parallel interacting pathways. To get insight into the mechanism how PKA may block gdt1, we have tested two putative PKA phosphorylation sites in the protein and found that one of them is efficiently phosphorylated by PKA in vitro. A model for the interplay between PKA and gdt1 during the growth-differentiation-transition is discussed.
Collapse
Affiliation(s)
- C Zeng
- Department of Genetics, Kassel University, Heinrich-Plett-Str. 40 D-34132 Kassel, Germany
| | | | | | | | | | | |
Collapse
|
11
|
Wilkins A, Chubb JR, Insall RH. A novel Dictyostelium RasGEF is required for normal endocytosis, cell motility and multicellular development. Curr Biol 2000; 10:1427-37. [PMID: 11102804 DOI: 10.1016/s0960-9822(00)00797-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Dictyostelium possesses a surprisingly large number of Ras proteins and little is known about their activators, the guanine nucleotide exchange factors (GEFs). It is also unclear, in Dictyostelium or in higher eukaryotes, whether Ras pathways are linear, with each Ras controlled by its own GEF, or networked, with multiple GEFs acting on multiple Ras proteins. RESULTS We have identified the Dictyostelium gene that encodes RasGEFB, a protein with homology to known RasGEFs such as the Son-of-sevenless (Sos) protein. Dictyostelium cells in which the gene for RasGEFB was disrupted moved unusually rapidly, but lost the ability to perform macropinocytosis and therefore to grow in liquid medium. Crowns, the sites of macropinocytosis, were replaced by polarised lamellipodia. Mutant cells were also profoundly defective in early development, although they eventually formed tiny but normally proportioned fruiting bodies. This defect correlated with loss of discoidin Igamma mRNA, a starvation-induced gene, although other genes required for development were expressed normally or even precociously. RasGEFB was able to rescue a Saccharomyces CDC25 mutant, indicating that it is a genuine GEF for Ras proteins. CONCLUSIONS RasGEFB appears to be the principal activator of the RasS protein, which regulates macropinocytosis and cell speed, but it also appears to regulate one or more other Ras proteins.
Collapse
Affiliation(s)
- A Wilkins
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, WC1E 6BT, London, UK
| | | | | |
Collapse
|
12
|
Ortiz D, del Carmen Dominguez-Robles M, Villegas-Sepúlveda N, Meza I. Actin induction during PMA and cAMP-dependent signal pathway activation in Entamoeba histolytica trophozoites. Cell Microbiol 2000; 2:391-400. [PMID: 11207595 DOI: 10.1046/j.1462-5822.2000.00060.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Activation of PKC or cAMP-dependent signalling pathways in Entamoeba histolytica triggers the phosphorylation of proteins involved in actin rearrangements necessary for adhesion and locomotion. Analogous motifs to SRE and CRE sequences--known to respond to PMA and cAMP--were identified within the 5' regulatory region (5'RR) of one of the parasite actin genes. These sequences could be involved in the actin transcriptional upregulation reported during signalling. To test this hypothesis, a plasmid containing the 5'RR of the actin gene fused to the bacterial neomycin gene (neo) was used for stable transfection. Expression of neo and endogenous actin was measured after stimulation of transfected amoebae by PMA and dcAMP. It was found that both compounds induced neo and actin expression and showed a co-operative effect in the induction of neo. Induction by PMA or dcAMP failed if the directing amoebic 5'RR lacked SRE and CRE motifs. Transfection of amoebae with plasmid constructs, containing either progressive deletions of the actin 5'RR or site-directed mutations of the SRE and CRE-like motifs, corroborated that these sequences and a co-ordinated participation of PKC- and PKA-activated transcription factors are responsible for the increments in neo and actin mRNAs. In vivo, these PMA and cAMP-response elements could play an important role in regulating actin expression and organization in signalling processes activated during tissue invasion.
Collapse
Affiliation(s)
- D Ortiz
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México, DF, Mexico
| | | | | | | |
Collapse
|
13
|
Palmieri SJ, Nebl T, Pope RK, Seastone DJ, Lee E, Hinchcliffe EH, Sluder G, Knecht D, Cardelli J, Luna EJ. Mutant Rac1B expression in Dictyostelium: effects on morphology, growth, endocytosis, development, and the actin cytoskeleton. CELL MOTILITY AND THE CYTOSKELETON 2000; 46:285-304. [PMID: 10962483 DOI: 10.1002/1097-0169(200008)46:4<285::aid-cm6>3.0.co;2-n] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Rac1 is a small G-protein in the Ras superfamily that has been implicated in the control of cell growth, adhesion, and the actin-based cytoskeleton. To investigate the role of Rac1 during motile processes, we have established Dictyostelium cell lines that conditionally overexpress epitope-tagged Dictyostelium discoideum wild-type Rac1B (DdRac1B) or a mutant DdRac1B protein. Expression of endogenous levels of myc- or GFP-tagged wild-type DdRac1B had minimal effect on cellular morphologies and behaviors. By contrast, expression of a constitutively active mutant (G12-->V or Q61-->L) or a dominant negative mutant (T17-->N) generated amoebae with characteristic cellular defects. The morphological appearance of actin-containing structures, intracellular levels of F-actin, and cellular responses to chemoattractant closely paralleled the amount of active DdRac1B, indicating a role in upregulating actin cytoskeletal activities. Expression of any of the three mutants inhibited cell growth and cytokinesis, and delayed multicellular development, suggesting that DdRac1B plays important regulatory role(s) during these processes. No significant effects were observed on binding or internalization of latex beads in suspension or on intracellular membrane trafficking. Cells expressing DdRac1B-G12V exhibited defects in fluid-phase endocytosis and the longest developmental delays; DdRac1B-Q61L produced the strongest cytokinesis defect; and DdRac1B-T17N generated intermediate phenotypes. These conditionally expressed DdRac1B proteins should facilitate the identification and characterization of the Rac1 signaling pathway in an organism that is amenable to both biochemical and molecular genetic manipulations.
Collapse
Affiliation(s)
- S J Palmieri
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Primpke G, Iassonidou V, Nellen W, Wetterauer B. Role of cAMP-dependent protein kinase during growth and early development of Dictyostelium discoideum. Dev Biol 2000; 221:101-11. [PMID: 10772794 DOI: 10.1006/dbio.2000.9662] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
cAMP-dependent protein kinase (PKA) is an essential regulator of gene expression and cell differentiation during multicellular development of Dictyostelium discoideum. Here we show that PKA activity also regulates gene expression during the growth phase and at the transition from growth to development. Overexpression of PKA leads to overexpression of the discoidinIgamma promoter, while expression of the discoidinIgamma promoter is reduced when PKA activity is reduced, either by expression of a dominant negative mutant of the regulatory subunit or by disruption of the gene for the catalytic subunit (PKA-C). The discoidin phenotype of PKA-C null cells is cell autonomous. In particular, normal secretion of discoidin-inducing factors was demonstrated. In addition, PKA-C null cells are able to respond to media conditioned by PSF and CMF. We conclude that PKA is a major activator of discoidin expression. However, it is not required for production or transduction of the inducing extracellular signals. Therefore, PKA-dependent and PKA-independent pathways regulate the expression of the discoidin genes.
Collapse
Affiliation(s)
- G Primpke
- Zoologisches Institut, LMU München, Luisenstrasse 14, Munich, 80333, Germany
| | | | | | | |
Collapse
|
15
|
Zeng C, Anjard C, Riemann K, Konzok A, Nellen W. gdt1, a new signal transduction component for negative regulation of the growth-differentiation transition in Dictyostelium discoideum. Mol Biol Cell 2000; 11:1631-43. [PMID: 10793140 PMCID: PMC14872 DOI: 10.1091/mbc.11.5.1631] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Discoidin I expression was used as a marker to screen for mutants affected in the growth-differentiation transition (GDT) of Dictyostelium. By REMI mutagenesis we have isolated mutant 2-9, an overexpressor of discoidin I. It displays normal morphogenesis but shows premature entry into the developmental cycle. The disrupted gene was denominated gdt1. The mutant phenotype was reconstructed by disruptions in different parts of the gene, suggesting that all had a complete loss of function. gdt1 was expressed in growing cells; the levels of protein and mRNA appear to increase with cell density and rapidly decrease with the onset of development. gdt1 encodes a 175-kDa protein with four putative transmembrane domains. In the C terminus, the derived amino acid sequence displays some similarity to the catalytic domain of protein kinases. Mixing experiments demonstrate that the gdt1(-) phenotype is cell autonomous. Prestarvation factor is secreted at wild-type levels. The response to folate, a negative regulator of discoidin expression, was not impaired in gdt1 mutants. Cells that lack the G protein alpha2 display a loss of discoidin expression and do not aggregate. gdt1(-)/Galpha2(-) double mutants show no aggregation but strong discoidin expression. This suggests that gdt1 is a negative regulator of the GDT downstream of or in a parallel pathway to Galpha2.
Collapse
Affiliation(s)
- C Zeng
- Department of Genetics, Kassel University, 34132 Kassel, Germany
| | | | | | | | | |
Collapse
|
16
|
Abstract
Starving Dictyostelium amoebae use cAMP as a chemoattractant to gather into aggregates, as a hormone-like signal to induce cell differentiation, and as an intracellular messenger to control stalk- and spore cell maturation and germination of spores. In this chapter we describe the respective roles of the three adenylyl cyclases ACA, ACB and ACG in controlling cAMP signaling during development and we discuss how cAMP signals are processed by the cells to trigger the large repertoire of gene regulatory events that is under control of this signal molecule.
Collapse
Affiliation(s)
- M Meima
- Department of Biochemistry, University of Dundee, Dow Street, Dundee, Scotland, DD1 5EH, UK
| | | |
Collapse
|
17
|
Bonfils C, Gaudet P, Tsang A. Identification of cis-regulating elements and trans-acting factors regulating the expression of the gene encoding the small subunit of ribonucleotide reductase in Dictyostelium discoideum. J Biol Chem 1999; 274:20384-90. [PMID: 10400662 DOI: 10.1074/jbc.274.29.20384] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have examined the promoter of rnrB, the gene encoding the small subunit of ribonucleotide reductase of Dictyostelium discoideum, using lacZ as a reporter gene. Deletion analysis showed that expression of this gene in vegetative cells involves an A/T-rich element, whereas its expression in prespore cells during development requires a region encompassing two G/C-rich elements, designated box A and box B. Removal of boxes A and B results in very low level of activity. When either box A or box B is deleted, prestalk cells adjacent to the prespore zone also express beta-galactosidase. The behavior of these cis-regulatory elements implies that the mechanism regulating the prespore-specific expression of rnrB is different from that regulating other known prespore genes. We have used electrophoretic mobility shift assays to identify factors that interact with box A and box B. Box A interacts with a factor that is found in the nuclear fraction. While box B interacts with a factor that is present in the cytosolic fraction throughout growth and development, its presence in the nuclear fraction is developmentally regulated. Results from competition assays suggest that both box A and box B interact with transcriptional activators that have not been characterized previously.
Collapse
Affiliation(s)
- C Bonfils
- Department of Biology, Concordia University, Montreal, Quebec H3G 1M8, Canada
| | | | | |
Collapse
|
18
|
Yang C, Brar SK, Desbarats L, Siu CH. Synthesis of the Ca(2+)-dependent cell adhesion molecule DdCAD-1 is regulated by multiple factors during Dictyostelium development. Differentiation 1997; 61:275-84. [PMID: 9342838 DOI: 10.1046/j.1432-0436.1997.6150275.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In Dictyostelium discoideum, the cadA gene encodes the cell adhesion molecule DdCAD-1, a protein of M(r) 24,000, which mediates Ca(2+)-dependent cell-cell adhesion during development. We have examined the effects of cAMP, cell-cell contact, and growth conditions on cadA expression. cadA has a unique pattern of expression, which appears to be a combination of the expression patterns of early genes and aggregation-stage genes. Expression of the cadA gene in bacterially grown cells is activated at the beginning of the developmental cycle, followed by a period of rapid DdCAD-1 accumulation. The mRNA level reaches its maximum at 9 h of development and then declines to the basal level at approximately 18 h, while the protein level remains constant after reaching its maximum at 12 h. Pulse-chase experiments have demonstrated that DdCAD-1 has a significantly longer half-life than the average cellular protein. Transcription of the cadA gene is stimulated by exogenous cAMP pulses, leading to a 3- to 5-fold increase in the transcription rate. In the fgdA mutant, which lacks a functional G alpha 2, cAMP fails to enhance cadA expression, suggesting that cAMP stimulates cadA transcription via a G protein-dependent pathway. However, inhibition of cell-cell contact has no effect on the synthesis of DdCAD-1. Growth conditions also have a major influence on cadA expression. Axenically grown cells produce a high level of cadA transcripts during vegetative growth. The mRNA level shows a steady decrease during development and is reduced to the basal level by 12 h. In contrast, the level of DdCAD-1 remains relatively high throughout development, suggesting that axenic growth affects the accumulation of cadA mRNA but not the stability of the protein. These results indicate that multiple mechanisms are involved to maintain a high level of DdCAD-1 during development.
Collapse
Affiliation(s)
- C Yang
- Banting and Best Department of Medical Research, University of Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
19
|
Rutherford CL, Selmin O, Peters-Weigel S. Temporal regulation of the Dictyostelium glycogen phosphorylase 2 gene. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1351:111-25. [PMID: 9116024 DOI: 10.1016/s0167-4781(96)00182-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The product of the glycogen phosphorylase-2 gene in Dictyostelium functions to provide the glucose units that are used to construct the structural components of the terminal stage of development. In this report, we link a 1233 bp upstream gp2 fragment to a luciferase reporter gene in order to study the sequences that are involved in the temporal expression of the gene. Various deletions of the promoter-luciferase fusion were then transformed into Dictyostelium cells. All deletion constructs, from -1216 to -486 nucleotides from the translational start codon, showed the same temporal pattern of expression as the authentic gp2 gene, as well as similar luciferase activities. Removal of an additional 37 nucleotides resulted in nearly 100-fold decrease in activity, yet retained the normal temporal expression of luciferase. Analysis of DNA binding proteins with the gel shift assay revealed a stage-dependent pattern of proteins that bound to the gp2 promoter. A similar pattern of temporal expression of the binding proteins was observed with either the full-length probe or with oligonucleotide probes that contained sequences that were identified as putative regulatory sites. Likewise, the full-length and oligonucleotide probes demonstrated identical binding patterns during several steps of purification of the DNA binding proteins. SDS-PAGE and Southwestern blot analysis of a DNA-affinity purified fraction, identified a 23 kDa peptide as the binding protein.
Collapse
Affiliation(s)
- C L Rutherford
- Biology Department, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
| | | | | |
Collapse
|
20
|
Kumimoto H, Yoshida H, Okamoto K. Expression of Dictyostelium early gene, dutA, is independent of cAMP pulses but dependent on protein kinase A. FEMS Microbiol Lett 1996. [DOI: 10.1111/j.1574-6968.1996.tb08324.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
21
|
Clarke M, Gomer RH. PSF and CMF, autocrine factors that regulate gene expression during growth and early development of Dictyostelium. EXPERIENTIA 1995; 51:1124-34. [PMID: 8536800 DOI: 10.1007/bf01944730] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Throughout growth and development, Dictyostelium cells secrete autocrine factors that accumulate in proportion to cell density. At sufficient concentration, these factors cause changes in gene expression. Vegetative Dictyostelium cells continuously secrete prestarvation factor (PSF). The bacteria upon which the cells feed inhibit their response to PSF, allowing the cells to monitor their own density in relation to that of their food supply. At high PSF/bacteria ratios, which occur during late exponential growth, PSF induces the expression of several genes whose products are needed for cell aggregation. When the food supply has been depleted, PSF production declines, and a second density-sensing pathway is activated. Starving cells secrete conditioned medium factor (CMF), a glycoprotein of Mr 80 kDa that is essential for the development of differentiated cell types. Antisense mutagenesis has shown that cells lacking CMF cannot aggregate, and preliminary data suggest that CMF regulates cAMP signal transduction. Calculations indicate that a mechanism of simultaneously secreting and recognizing a signal molecule, as used by Dictyostelium to monitor cell density, could also be used to determine the total number of cells in a tissue.
Collapse
Affiliation(s)
- M Clarke
- Oklahoma Medical Research Foundation, Program in Molecular and Cell Biology, Oklahoma City 73104, USA
| | | |
Collapse
|
22
|
Wetterauer BW, Salger K, Carballo-Metzner C, MacWilliams HK. Cell-density-dependent repression of discoidin in Dictyostelium discoideum. Differentiation 1995; 59:289-97. [PMID: 8882814 DOI: 10.1046/j.1432-0436.1996.5950289.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
When Dictyostelium discoideum cells are grown on bacteria, their natural food source, the discoidin genes are induced by cell-density-sensing factors before the food supply is exhausted [11, 18], and expression increases continuously thereafter. This regulation pattern is changed when cells are grown in axenic medium: the discoidins are induced at a considerably lower cell density and are no longer expressed in stationary phase [13]. We have investigated this phenomenon further and show that repression begins when cells are still in exponential growth. It occurs at the level of transcription and involves an element of the discoidin I gamma promoter for which no function has previously been described. Since the effect of high cell density can be mimicked by conditioned medium, it appears that the repression is due to an extracellular signal. This signal is neither ammonia, nor folate, nor cAMP, the known repressors of discoidin expression.
Collapse
Affiliation(s)
- B W Wetterauer
- Zoologisches Institut der Ludwig-Maximilians-Universität, München, Germany
| | | | | | | |
Collapse
|
23
|
Voith G, Dingermann T. Expression of the human muscarinic receptor gene m2 in Dictyostelium discoideum. BIO/TECHNOLOGY (NATURE PUBLISHING COMPANY) 1995; 13:1225-9. [PMID: 9636297 DOI: 10.1038/nbt1195-1225] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have expressed a functional human muscarinic M2 receptor, under the control of the homologous discoidin I gamma promoter, in the cellular slime mold Dictyostelium discoideum. The use of a contact site A leader peptide ensured insertion of the newly synthesized receptor protein into the plasma membrane. Due to the characteristics of the discoidin I gamma promoter, the M2 receptor is expressed during late growth and early development. The heterologously expressed M2 receptors show binding characteristics similar to authentic receptors. Membranes as well as whole cells can be used in ligand binding assays.
Collapse
Affiliation(s)
- G Voith
- Institut für Pharmazeutische Biologie, Johann Wolfgang Goethe Universität, Frankfurt, Germany
| | | |
Collapse
|
24
|
Reymond CD, Beghdadi-Rais C, Roggero M, Duarte EA, Desponds C, Bernard M, Groux D, Matile H, Bron C, Corradin G. Anchoring of an immunogenic Plasmodium falciparum circumsporozoite protein on the surface of Dictyostelium discoideum. J Biol Chem 1995; 270:12941-7. [PMID: 7759554 DOI: 10.1074/jbc.270.21.12941] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The circumsporozoite protein (CSP), a major antigen of Plasmodium falciparum, was expressed in the slime mold Dictyostelium discoideum. Fusion of the parasite protein to a leader peptide derived from Dictyostelium contact site A was essential for expression. The natural parasite surface antigen, however, was not detected at the slime mold cell surface as expected but retained intracellularly. Removal of the last 23 amino acids resulted in secretion of CSP, suggesting that the C-terminal segment of the CSP, rather than an ectoplasmic domain, was responsible for retention. Cell surface expression was obtained when the CSP C-terminal segment was replaced by the D. discoideum contact site A glycosyl phosphatidylinositol anchor signal sequence. Mice were immunized with Dictyostelium cells harboring CSP at their surface. The raised antibodies recognized two different regions of the CSP. Anti-sporozoite titers of these sera were equivalent to anti-peptide titers detected by enzyme-linked immunosorbent assay. Thus, cell surface targeting of antigens can be obtained in Dictyostelium, generating sporozoite-like cells having potentials for vaccination, diagnostic tests, or basic studies involving parasite cell surface proteins.
Collapse
Affiliation(s)
- C D Reymond
- Institute of Histology and Embryology, University of Lausanne, Switzerland
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Blusch J, Alexander S, Nellen W. Multiple signal transduction pathways regulate discoidin I gene expression in Dictyostelium discoideum. Differentiation 1995; 58:253-60. [PMID: 7641976 DOI: 10.1046/j.1432-0436.1995.5840253.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The expression of the discoidin I genes in Dictyostelium discoideum is regulated by the concerted action of the extracellular factors cyclic adenosine monophosphate (cAMP), folate, prestarvation factor (PSF) and conditioned media factor (CMF). However, the pathways by which these signals are transduced and the interactions between the pathways have been unexplored so far. We have analysed wild-type and mutant cells with defined lesions in signal transduction to elucidate these regulatory processes, and shown that different pathways are used for the down-regulation and induction of these genes. The cAMP receptor cARI is required for the cAMP-mediated down-regulation of discoidin I gene expression but not for the induction of discoidin I expression during development. Surprisingly, induction of the discoidin I genes requires G alpha 2, the G-protein subunit which is generally believed to couple to cARI, to control the expression of cAMP-inducible genes. Thus, our data suggest that G alpha 2 interacts with different receptors to regulate gene expression in early development. Furthermore, the analysis shows that discoidin induction in bacterially grown cells occurs in two sequential steps. The first is a low basal induction which occurs in late log-phase growth prior to starvation. PSF can induce the basal level, and the induction is independent of G alpha 2. The developmental induction following starvation is much stronger, dependent on G alpha 2 and probably signaled by CMF, which is secreted at that time.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J Blusch
- Max-Planck-Institut für Biochemie, Abteilung Zellbiologie, Martinsried, Germany
| | | | | |
Collapse
|
26
|
Bäuerle A, Mutzel R. Nucleotide sequence of the gene for ribosomal protein S17 from Dictyostelium discoideum. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1260:223-6. [PMID: 7841201 DOI: 10.1016/0167-4781(94)00218-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The nucleotide sequence of the gene for the Dictyostelium homologue of eukaryotic ribosomal protein S17 has been assembled from cDNA and genomic DNA clones. The predicted primary structure of the S17 protein displays a similar level of sequence identity with its counterparts from higher eukaryotes (53%) as other Dictyostelium ribosomal proteins. Although Dictyostelium genes usually are organized in a rather simple manner, the rps17 gene harbors two introns. One of them, located immediately 3' from the ATG initiator codon, appears to be ubiquitously conserved in eukaryotic rps17 genes.
Collapse
Affiliation(s)
- A Bäuerle
- Fakultät für Biologie, Universität Konstanz, Germany
| | | |
Collapse
|
27
|
Blusch JH, Nellen W. Folate responsiveness during growth and development of Dictyostelium: separate but related pathways control chemotaxis and gene regulation. Mol Microbiol 1994; 11:331-5. [PMID: 8170395 DOI: 10.1111/j.1365-2958.1994.tb00313.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Folate-controlled gene expression and chemotaxis have been examined in Dictyostelium wild-type and mutant strains. We show that regulation of the discoidin genes is sensitive to folate in growing cells as well as in suspension development. The signal is transferred via the N10-methylfolate-sensitive folate receptor sites, which also appear to confer the chemotactic response. The strain HG5145 has previously been isolated as a mutant that does not display chemotactic movement towards folate. Nevertheless, these cells are fully functional in folate-mediated downregulation of discoidin I expression. The strain ga 93 has been isolated as an overproducer mutant of the cyclic nucleotide phosphodiesterase inhibitor. Simultaneously, these cells fail to downregulate discoidin I in response to folate but are fully functional in folate chemotaxis. Therefore we conclude that the pathways for chemotaxis and for gene regulation diverge downstream of a common receptor type.
Collapse
Affiliation(s)
- J H Blusch
- Max-Planck-Institut für Biochemie, Martinsried, Germany
| | | |
Collapse
|
28
|
Sadiq M, Hildebrandt M, Maniak M, Nellen W. Developmental regulation of antisense-mediated gene silencing in Dictyostelium. ANTISENSE RESEARCH AND DEVELOPMENT 1994; 4:263-7. [PMID: 7734941 DOI: 10.1089/ard.1994.4.263] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In Dictyostelium, the expression of antisense transcripts has been successfully used to reduce or eliminate gene expression. In most cases this occurs on the level of RNA stability resulting in a loss of both sense and antisense transcript accumulation. We here show that the antisense effect is regulated during the developmental cycle, i.e., in certain developmental stages and under certain developmental conditions, complementary RNAs appear not to interact with each other, resulting in a failure to abolish expression of the gene of interest. We find that this is not only the case with artificially introduced antisense constructs but also with the endogenous, antisense-regulated PSV-A gene. Our data demonstrate that antisense-mediated gene silencing is conferred by a biochemical machinery that is subject to regulation in vivo. The results provide a basis to better understand this machinery and to dissect the components. They may also explain the failure of some antisense experiments in Dictyostelium and possibly in other organisms.
Collapse
Affiliation(s)
- M Sadiq
- Yamouk University, Irbid, Jordan
| | | | | | | |
Collapse
|
29
|
Ken R, Singleton CK. Redundant regulatory elements account for the developmental control of a ribosomal protein gene of Dictyostelium discoideum. Differentiation 1994; 55:97-103. [PMID: 8143933 DOI: 10.1046/j.1432-0436.1994.5520097.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In Dictyostelium discoideum, ribosomal protein genes along with other growth specific genes appear to be coordinately regulated, primarily in response to differences in the translational capacity of developing versus growing cells. In particular, expression of the members of this large class of genes is rapidly and dramatically deactivated when the developmental program is initiated and growth and division cease. In order to understand the mechanisms behind the deactivation event and how it is coupled to the transition from growth to development, we have analyzed the promoter of the V18 gene, a ribosomal protein gene characteristic of this class of growth specific genes. We have delineated three discrete regions involved in the transcription and regulation of the V18 gene. A initiator region which appears to function in a TATA-independent manner was required for transcription and for establishing start site utilization. Two regions upstream of this were defined, both of which were found to independently confer proper developmental regulation.
Collapse
Affiliation(s)
- R Ken
- Department of Molecular Biology, Vanderbilt University, Nashville, TN 37235
| | | |
Collapse
|
30
|
Schatzle J, Bush J, Dharmawardhane S, Firtel R, Gomer R, Cardelli J. Characterization of the signal transduction pathways and cis-acting DNA sequence responsible for the transcriptional induction during growth and development of the lysosomal alpha-mannosidase gene in Dictyostelium discoideum. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)36563-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
31
|
Fukuzawa M, Ochiai H. Spatiotemporal Patterning of discoidin I and II during Development of Dictyostelium discoideum. (cellular slime mold/Dictyostelium discoideum/lectin/discoidin/cell type-specific localization). Dev Growth Differ 1993. [DOI: 10.1111/j.1440-169x.1993.00011.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
32
|
Alexander S, Sydow LM, Wessels D, Soll DR. Discoidin proteins of Dictyostelium are necessary for normal cytoskeletal organization and cellular morphology during aggregation. Differentiation 1992; 51:149-61. [PMID: 1334012 DOI: 10.1111/j.1432-0436.1992.tb00691.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The onset of aggregation of bacterially-grown Dictyostelium discoideum amoebae is accompanied by the accumulation of the discoidin proteins. An immunofluorescent analysis demonstrates that discoidin is distributed throughout the cytoplasm, but is excluded from vesicles and nucleoli. There is no indication of either extracellular or membrane localization. Translocating amoebae of mutants lacking discoidin form more dispersed pseudopodial regions at the cell periphery, possess an abnormally centered microtubule organizing center, are blunt rather than elongate, and lack the tapered posterior uropod characteristic of translocating wild-type cells. However, in spite of the loss of the normal elongate morphology, discoidinless mutants translocate with instantaneous velocities and directional persistence comparable to wild-type cells, and they respond normally to the rapid addition of cAMP. These results demonstrate that the discoidin proteins are cytoplasmic components essential for the maintenance of the elongate cell morphology, cytoskeletal organization and the ability to align with other cells during aggregation. However, the elongate morphology is not a requisite for rapid and persistent single cell translocation.
Collapse
Affiliation(s)
- S Alexander
- Division of Biological Sciences, University of Missouri, Columbia 65211
| | | | | | | |
Collapse
|
33
|
Identification of a unique cAMP-response element in the gene encoding the cell adhesion molecule gp80 in Dictyostelium discoideum. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41825-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
34
|
Anjard C, Pinaud S, Kay RR, Reymond CD. Overexpression of Dd PK2 protein kinase causes rapid development and affects the intracellular cAMP pathway of Dictyostelium discoideum. Development 1992; 115:785-90. [PMID: 1330484 DOI: 10.1242/dev.115.3.785] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Dd PK2 gene codes for a putative protein of 648 amino acids with a C-terminal half sharing high homology with protein kinase A catalytic subunits from other organisms. In order to find out more about the physiological role of the Dd PK2 kinase, its gene, and a version having a frame shift mutation in the middle of the catalytic region, were overexpressed in developing Dictyostelium cells. Both the intact gene (K-) and the frame shift mutant (Kdel-) caused rapid development with spores formed in 16–18 hours compared to the 24 hours required by their parent. This result was confirmed by the pattern of expression of some developmentally regulated genes. Other rapid developing strains (rde) are activated in the cAMP second messenger system. Both K- and Kdel-containing strains have lower cAMP levels than the parental strain during late development, thus resembling rdeC mutants. K-cells (but not Kdel-cells) produced bizarre fruiting bodies with many prostrate forms. The parallel with rde mutants was confirmed by demonstrating that K-cells are able to form spores in submerged monolayer culture. Furthermore, K-cells have about four times more protein kinase A (cAPK) activity than wild-type cells. These results indicate that the N-terminal domain of Dd PK2 is sufficient to influence cAMP levels and to provoke rapid development, whereas kinase activity seems to be required for the sporogenous phenotype. The association between elevated cAPK and Dd PK2 overexpression phenotype further indicates a role for cAPK in the formation of spores.
Collapse
Affiliation(s)
- C Anjard
- Swiss Experimental Cancer Research Institute, ISREC, Epalinges
| | | | | | | |
Collapse
|
35
|
Goldman GH, Geremia RA, Caplan AB, Vila SB, Villarroel R, Van Montagu M, Herrera-Estrella A. Molecular characterization and regulation of the phosphoglycerate kinase gene from Trichoderma viride. Mol Microbiol 1992; 6:1231-42. [PMID: 1588821 DOI: 10.1111/j.1365-2958.1992.tb01562.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have isolated the phosphoglycerate kinase gene (pgk) of Trichoderma viride and characterized its expression. Comparison of genomic and cDNA clones allowed the correct deduction of the intron boundaries and the 3'-end cleavage site of this gene. Primer extension analysis showed that transcription initiated at three start points between -296 and -298 bp upstream of the translational start codon. The promoter sequence contained a number of cis-acting sequences commonly found in eukaryotic promoters. The pgk transcript analysis of T. viride grown on defined carbon sources showed that neither rate nor growth phase greatly affects pgk expression. By contrast, when Trichoderma spp. were grown in the presence of cell walls of a phytopathogenic fungus as carbon source, pgk messenger levels dropped markedly. This suggests that pgk mRNA accumulation is specifically repressed in the simulated mycoparasitic state.
Collapse
Affiliation(s)
- G H Goldman
- Laboratorium voor Genetica, Universiteit Gent, Belgium
| | | | | | | | | | | | | |
Collapse
|
36
|
Hildebrandt M, Nellen W. Differential antisense transcription from the Dictyostelium EB4 gene locus: implications on antisense-mediated regulation of mRNA stability. Cell 1992; 69:197-204. [PMID: 1555240 DOI: 10.1016/0092-8674(92)90130-5] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The 2.2 kb mRNA of the Dictyostelium discoideum prespore gene EB4-PSV is constitutively transcribed during growth and development, but the message is only accumulated when cells form aggregates and establish the prespore-prestalk pattern. Disruption of the pattern by mechanical disaggregation results in a rapid loss of the mRNA, while transcription remains nearly unchanged. In early development and after disaggregation, when the mRNA is unstable, a 1.8 kb antisense transcript originating from the same gene locus is detected. This RNA has apparently no coding capacity and is transcriptionally regulated by a promoter located within the translated region of the gene. Excess transcription of antisense RNA in vegetative cells and after disaggregation suggests its involvement in the control of mRNA stability. In agreement with this assumption, the inhibition of RNA synthesis during disaggregation prevents destabilization of the mRNA. This stability regulation of an endogenous mRNA is reminiscent of the loss of specific mRNAs in cells transformed with antisense constructs.
Collapse
Affiliation(s)
- M Hildebrandt
- Max-Planck-Institut für Biochemie, Martinsried, Germany
| | | |
Collapse
|
37
|
Robbins SM, Williams JG, Spiegelman GB, Weeks G. Cloning and characterization of the Dictyostelium discoideum rasG genomic sequences. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1130:85-9. [PMID: 1339294 DOI: 10.1016/0167-4781(92)90467-e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A Dictyostelium discoideum genomic DNA clone containing the ras-related gene, rasG was isolated using the rasG cDNA as a probe. The genomic clone encompasses the entire coding region of the gene and 1.5 kb of 5' flanking region. The rasG gene contains a single intron as determined by sequence comparison with the cDNA, whereas the highly related rasD gene contains three introns. Primer extension analysis showed that transcription of the rasG gene initiates at multiple sites. Sequence analysis of the 5' flanking region of the gene revealed a stretch of thymine residues upstream from the transcription start sites but there is no evidence for a TATA box sequence.
Collapse
Affiliation(s)
- S M Robbins
- Department of Microbiology, University of British Columbia, Vancouver, Canada
| | | | | | | |
Collapse
|
38
|
Schatzle J, Bush J, Cardelli J. Molecular cloning and characterization of the structural gene coding for the developmentally regulated lysosomal enzyme, alpha-mannosidase, in Dictyostelium discoideum. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50624-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
39
|
Rathi A, Clarke M. Expression of early developmental genes in Dictyostelium discoideum is initiated during exponential growth by an autocrine-dependent mechanism. Mech Dev 1992; 36:173-82. [PMID: 1315152 DOI: 10.1016/0925-4773(92)90068-u] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Throughout growth, Dictyostelium cells continuously produce an autocrine factor, PSF, that accumulates in proportion to cell density. Production of PSF declines rapidly when cells are shifted to starvation conditions, and the properties of PSF are distinct from those of regulatory factors produced by starving cells. During late exponential growth, PSF induces expression of several early developmental genes, including those for proteins important in cAMP signaling and cell aggregation. Examples are the aggregation stage cAMP receptor (cAR1), the aggregation-specific form of cyclic nucleotide phosphodiesterase, and gp24 (contact sites B). Through PSF, growing cells detect environmental conditions (cell number high, food approaching depletion) that are appropriate for production of the gene products needed to initiate aggregation and development.
Collapse
Affiliation(s)
- A Rathi
- Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City 73104
| | | |
Collapse
|
40
|
New nucleotide sequence data on the EMBL File Server. Nucleic Acids Res 1991; 19:1967-70. [PMID: 2030988 PMCID: PMC328160 DOI: 10.1093/nar/19.8.1967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
|
41
|
Maniak M, Nellen W. 3' processing in Dictyostelium: unusual sequence requirements and interaction with a downstream promoter. Mol Microbiol 1991; 5:245-51. [PMID: 2041469 DOI: 10.1111/j.1365-2958.1991.tb02105.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have determined the sequence requirements for 3'-processing in Dictyostelium and find that a single AATAAA site, embedded in an A/T-rich environment is sufficient. A synthetic oligonucleotide containing the additional GT/T-rich element, which is necessary for 3'-processing in higher eukaryotes, is not used in Dictyostelium. On the basis of reports suggesting termination signals (upstream terminators) in Dictyostelium promoters, we investigated possible interactions between processing signals and regulatory elements. Our data suggest that upstream termination enhances transcription from a downstream promoter.
Collapse
Affiliation(s)
- M Maniak
- Abteilung Zellbiologie, Max-Planck-Institut für Biochemie, Martinsried, Germany
| | | |
Collapse
|
42
|
May T, Blusch J, Sachse A, Nellen W. A cis-acting element responsible for early gene induction by extracellular cAMP in Dictyostelium discoideum. Mech Dev 1991; 33:147-55. [PMID: 1851628 DOI: 10.1016/0925-4773(91)90081-g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have analysed the promoter of the Dictyostelium discoideum alpha-L-fucosidase (ALF) gene, and have identified a 58 bp fragment responsible for transcriptional activation mediated by extracellular cAMP. Replacement of regulatory sequences in the cAMP-independent actin 15 promoter by this fragment confers cAMP regulation to the hybrid promoter. A cAMP analog with high affinity to the cell surface cAMP receptor can induce transcription from the endogenous as well as from the hybrid promoter. Gel-shift experiments show that the 58 bp fragment is a target for nuclear DNA-binding proteins, and that a specific complex is formed in response to cAMP stimulation. The major cAMP-dependent DNA.protein complex is formed with a 22 bp subfragment which we have termed DCRE (Dictyostelium cAMP responsive element).
Collapse
Affiliation(s)
- T May
- Max-Planck-Institut für Biochemie, Abt. Zellbiologie, Martinsried, F.R.G
| | | | | | | |
Collapse
|
43
|
Hildebrandt M, Saur U, Nellen W. Structure, expression, and inactivation by gene disruption of the Dictyostelium discoideum prespore gene EB4. DEVELOPMENTAL GENETICS 1991; 12:163-9. [PMID: 2049876 DOI: 10.1002/dvg.1020120125] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We present the nucleotide sequence of the cell type specific prespore gene EB4 which encodes a protein containing a hydrophobic leader sequence and two distinct domains of amino acid repeats. By RNase protection experiments we have determined the genomic organization of the gene which differs substantially from the previously published data. An antibody directed against one of the repeat structures (hexamer repeat) specifically reacts with a developmentally regulated antigen of 58 kd. Gene disruption transformants were obtained by transformation with a genomic DNA fragment. The transformants express a 3' truncated mRNA and do not react with the anti-hexamer antibody. So far, we could not detect any phenotypic aberrations in the transformed cell line.
Collapse
Affiliation(s)
- M Hildebrandt
- Max-Planck-Institut f. Biochemie, Abt. Zellbiologie, Martinsried, Federal Republic of Germany
| | | | | |
Collapse
|