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Han HL, Li JM, Chen D, Zhai XD, Smagghe G, Jiang H, Wang JJ, Wei D. Overexpression of miR-927-5p suppresses stalky expression and negatively reduces the spermatid production in Zeugodacus cucurbitae. PEST MANAGEMENT SCIENCE 2024; 80:3412-3422. [PMID: 38407521 DOI: 10.1002/ps.8044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
BACKGROUND The melon fly, Zeugodacus cucurbitae Coquillett, is one of the major pests attacking Cucurbitaceae crops. Identifying critical genes or proteins regulating fertility is essential for sustainable pest control and a research hotspot in insect physiology. MicroRNAs (miRNAs) are short RNAs that do not directly participate in protein translation, but instead function in post-transcriptional regulation of gene expression involved in male fertility. RESULTS We found that miR-927-5p is highly expressed in the testes and investigated its function in spermatogenesis in Z. cucurbitae. Fluorescence in situ hybridization (FISH) showed miR-927-5p in the transformation and maturation region of the testis, and overexpression of miR-927-5p reduced the number of sperms by 53%. In continuation, we predicted 12 target genes of miR-927-5p using bioinformatics combined with transcriptome sequencing data, and found that miR-927-5p targets the new gene Stalky in insects, which was validated by quantitative real-time PCR, RNA pull-down and dual luciferase reporter assays. FISH also confirmed the co-localization of miR-927-5p and the transcript Stalky_1 in the testis. Moreover, silencing of Stalky_1 by RNA interference reduced the number of sperms by 32% and reduced sperm viability by 39% in physiologically mature male adults. Meanwhile, the silencing of Stalky_1 also resulted in low hatchability. CONCLUSION Our work not only presents a new, so far unreported mechanism regulating spermatogenesis by miR-927-5p targeting a new unknown target, Stalky, which is providing new knowledge on the regulatory network of insect spermatogenesis, but also lays a foundation for the development of SIT against important tephritid fly pests. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Hong-Liang Han
- Chongqing Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
| | - Jing-Ming Li
- Chongqing Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
| | - Dong Chen
- Chongqing Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
| | - Xiao-Di Zhai
- Chongqing Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
| | - Guy Smagghe
- Chongqing Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Institute of Entomology, Guizhou University, Guiyang, China
| | - Hongbo Jiang
- Chongqing Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
| | - Jin-Jun Wang
- Chongqing Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
| | - Dong Wei
- Chongqing Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
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Abstract
Cooperation has been essential to the evolution of biological complexity, but many societies struggle to overcome internal conflicts and divisions. Dictyostelium discoideum, or the social amoeba, has been a useful model system for exploring these conflicts and how they can be resolved. When starved, these cells communicate, gather into groups, and build themselves into a multicellular fruiting body. Some cells altruistically die to form the rigid stalk, while the remainder sit atop the stalk, become spores, and disperse. Evolutionary theory predicts that conflict will arise over which cells die to form the stalk and which cells become spores and survive. The power of the social amoeba lies in the ability to explore how cooperation and conflict work across multiple levels, ranging from proximate mechanisms (how does it work?) to ultimate evolutionary answers (why does it work?). Recent studies point to solutions to the problem of ensuring fairness, such as the ability to suppress selfishness and to recognize and avoid unrelated individuals. This work confirms a central role for kin selection, but also suggests new explanations for how social amoebae might enforce cooperation. New approaches based on genomics are also enabling researchers to decipher for the first time the evolutionary history of cooperation and conflict and to determine its role in shaping the biology of multicellular organisms.
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Affiliation(s)
- Elizabeth A Ostrowski
- School of Natural and Computational Sciences, Massey University, Auckland, New Zealand.
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Forbes G, Chen ZH, Kin K, Lawal HM, Schilde C, Yamada Y, Schaap P. Phylogeny-wide conservation and change in developmental expression, cell-type specificity and functional domains of the transcriptional regulators of social amoebas. BMC Genomics 2019; 20:890. [PMID: 31752673 PMCID: PMC6873476 DOI: 10.1186/s12864-019-6239-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/29/2019] [Indexed: 11/17/2022] Open
Abstract
Background Dictyostelid social amoebas self-organize into fruiting bodies, consisting of spores and up to four supporting cell types in the phenotypically most complex taxon group 4. High quality genomes and stage- and cell-type specific transcriptomes are available for representative species of each of the four taxon groups. To understand how evolution of gene regulation in Dictyostelia contributed to evolution of phenotypic complexity, we analysed conservation and change in abundance, functional domain architecture and developmental regulation of their transcription factors (TFs). Results We detected 440 sequence-specific TFs across 33 families, of which 68% were upregulated in multicellular development and about half conserved throughout Dictyostelia. Prespore cells expressed two times more TFs than prestalk cells, but stalk cells expressed more TFs than spores, suggesting that gene expression events that define spores occur earlier than those that define stalk cells. Changes in TF developmental expression, but not in TF abundance or functional domains occurred more frequently between group 4 and groups 1–3, than between the more distant branches formed by groups 1 + 2 and 3 + 4. Conclusions Phenotypic innovation is correlated with changes in TF regulation, rather than functional domain- or TF acquisition. The function of only 34 TFs is known. Of 12 TFs essential for cell differentiation, 9 are expressed in the cell type for which they are required. The information acquired here on conserved cell type specifity of 120 additional TFs can effectively guide further functional analysis, while observed evolutionary change in TF developmental expression may highlight how genotypic change caused phenotypic innovation.
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Affiliation(s)
- Gillian Forbes
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | - Zhi-Hui Chen
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | - Koryu Kin
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | - Hajara M Lawal
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | | | - Yoko Yamada
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK.
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4
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Kin K, Forbes G, Cassidy A, Schaap P. Cell-type specific RNA-Seq reveals novel roles and regulatory programs for terminally differentiated Dictyostelium cells. BMC Genomics 2018; 19:764. [PMID: 30348074 PMCID: PMC6198379 DOI: 10.1186/s12864-018-5146-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/05/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A major hallmark of multicellular evolution is increasing complexity by the evolution of new specialized cell types. During Dictyostelid evolution novel specialization occurred within taxon group 4. We here aim to retrace the nature and ancestry of the novel "cup" cells by comparing their transcriptome to that of other cell types. RESULTS RNA-Seq was performed on purified mature spore, stalk and cup cells and on vegetative amoebas. Clustering and phylogenetic analyses showed that cup cells were most similar to stalk cells, suggesting that they share a common ancestor. The affinity between cup and stalk cells was also evident from promoter-reporter studies of newly identified cell-type genes, which revealed late expression in cups of many stalk genes. However, GO enrichment analysis reveal the unexpected prominence of GTPase mediated signalling in cup cells, in contrast to enrichment of autophagy and cell wall synthesis related transcripts in stalk cells. Combining the cell type RNA-Seq data with developmental expression profiles revealed complex expression dynamics in each cell type as well as genes exclusively expressed during terminal differentiation. Most notable were nine related hssA-like genes that were highly and exclusively expressed in cup cells. CONCLUSIONS This study reveals the unique transcriptomes of the mature cup, stalk and spore cells of D. discoideum and provides insight into the ancestry of cup cells and roles in signalling that were not previously realized. The data presented in this study will serve as an important resource for future studies into the regulation and evolution of cell type specialization.
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Affiliation(s)
- Koryu Kin
- School of Life Sciences, University of Dundee, Angus, Dundee, DD15EH UK
| | - Gillian Forbes
- School of Life Sciences, University of Dundee, Angus, Dundee, DD15EH UK
| | - Andrew Cassidy
- Tayside Centre for Genomic Analysis, University of Dundee, Angus, Dundee, DD19SY UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Angus, Dundee, DD15EH UK
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5
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Yamada Y, Cassidy A, Schaap P. The transcription factor Spores Absent A is a PKA dependent inducer of Dictyostelium sporulation. Sci Rep 2018; 8:6643. [PMID: 29704004 PMCID: PMC5923282 DOI: 10.1038/s41598-018-24915-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/11/2018] [Indexed: 11/09/2022] Open
Abstract
Sporulation in Dictyostelium fruiting bodies evolved from amoebozoan encystation with both being induced by cAMP acting on PKA, but with downstream components still being unknown. Using tagged mutagenesis to find missing pathway components, we identified a sporeless mutant defective in a nuclear protein, SpaA. Expression of prespore genes was strongly reduced in spaA- cells, while expression of many spore stage genes was absent. Chromatin immunoprecipitation (ChIP) of a SpaA-YFP gene fusion showed that (pre)spore gene promoters bind directly to SpaA, identifying SpaA as a transcriptional regulator. SpaA dependent spore gene expression required PKA in vivo and was stimulated in vitro by the membrane-permeant PKA agonist 8Br-cAMP. The PKA agonist also promoted SpaA binding to (pre)spore promoters, placing SpaA downstream of PKA. Sequencing of SpaA-YFP ChIPed DNA fragments revealed that SpaA binds at least 117 (pre)spore promoters, including those of other transcription factors that activate some spore genes. These factors are not in turn required for spaA expression, identifying SpaA as the major trancriptional inducer of sporulation.
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Affiliation(s)
- Yoko Yamada
- School of Life Sciences, University of Dundee, Dundee, DD15EH, Angus, UK
| | - Andrew Cassidy
- Tayside Centre for Genomic Analysis, University of Dundee, Dundee, DD19SY, Angus, UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Dundee, DD15EH, Angus, UK.
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6
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Loomis WF. A better way to discover gene function in the social amoeba Dictyostelium discoideum. Genome Res 2016; 26:1161-4. [PMID: 27586685 PMCID: PMC5052045 DOI: 10.1101/gr.209932.116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- William F Loomis
- Division of Biology, University of California San Diego, La Jolla, California 92093, USA
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Katoh-Kurasawa M, Santhanam B, Shaulsky G. The GATA transcription factor gene gtaG is required for terminal differentiation in Dictyostelium. J Cell Sci 2016; 129:1722-1733. [PMID: 26962009 DOI: 10.1242/jcs.181545] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The GATA transcription factor GtaG is conserved in Dictyostelids and essential for terminal differentiation in Dictyostelium discoideum, but its function is not well understood. Here we show that gtaG is expressed in prestalk cells at the anterior region of fingers and in the extending stalk during culmination. The gtaG- phenotype is cell-autonomous in prestalk cells and non-cell-autonomous in prespore cells. Transcriptome analyses reveal that GtaG regulates prestalk gene expression during cell differentiation before culmination and is required for progression into culmination. GtaG-dependent genes include genetic suppressors of the Dd-STATa-defective phenotype as well as Dd-STATa target-genes, including extra cellular matrix genes. We show that GtaG may be involved in the production of two culmination-signaling molecules, cyclic di-GMP and the spore differentiation factor SDF-1 and that addition of c-di-GMP rescues the gtaG- culmination and spore formation deficiencies. We propose that GtaG is a regulator of terminal differentiation that functions in concert with Dd-STATa and controls culmination through regulating c-di-GMP and SDF-1 production in prestalk cells.
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Affiliation(s)
- Mariko Katoh-Kurasawa
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston TX 77030, USA
| | - Balaji Santhanam
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston TX 77030, USA
| | - Gad Shaulsky
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston TX 77030, USA
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8
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Loomis WF. Genetic control of morphogenesis in Dictyostelium. Dev Biol 2015; 402:146-61. [PMID: 25872182 PMCID: PMC4464777 DOI: 10.1016/j.ydbio.2015.03.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/12/2015] [Accepted: 03/25/2015] [Indexed: 01/06/2023]
Abstract
Cells grow, move, expand, shrink and die in the process of generating the characteristic shapes of organisms. Although the structures generated during development of the social amoeba Dictyostelium discoideum look nothing like the structures seen in metazoan embryogenesis, some of the morphogenetic processes used in their making are surprisingly similar. Recent advances in understanding the molecular basis for directed cell migration, cell type specific sorting, differential adhesion, secretion of matrix components, pattern formation, regulation and terminal differentiation are reviewed. Genes involved in Dictyostelium aggregation, slug formation, and culmination of fruiting bodies are discussed.
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Affiliation(s)
- William F Loomis
- Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, United States.
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9
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Khare A, Shaulsky G. Cheating by exploitation of developmental prestalk patterning in Dictyostelium discoideum. PLoS Genet 2010; 6:e1000854. [PMID: 20195510 PMCID: PMC2829058 DOI: 10.1371/journal.pgen.1000854] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 01/23/2010] [Indexed: 11/25/2022] Open
Abstract
The cooperative developmental system of the social amoeba Dictyostelium discoideum is susceptible to exploitation by cheaters—strains that make more than their fair share of spores in chimerae. Laboratory screens in Dictyostelium have shown that the genetic potential for facultative cheating is high, and field surveys have shown that cheaters are abundant in nature, but the cheating mechanisms are largely unknown. Here we describe cheater C (chtC), a strong facultative cheater mutant that cheats by affecting prestalk differentiation. The chtC gene is developmentally regulated and its mRNA becomes stalk-enriched at the end of development. chtC mutants are defective in maintaining the prestalk cell fate as some of their prestalk cells transdifferentiate into prespore cells, but that defect does not affect gross developmental morphology or sporulation efficiency. In chimerae between wild-type and chtC mutant cells, the wild-type cells preferentially give rise to prestalk cells, and the chtC mutants increase their representation in the spore mass. Mixing chtC mutants with other cell-type proportioning mutants revealed that the cheating is directly related to the prestalk-differentiation propensity of the victim. These findings illustrate that a cheater can victimize cooperative strains by exploiting an established developmental pathway. Cooperative systems are susceptible to exploitation by cheaters who enjoy the benefits of cooperation without paying the costs. Such conflict is seen in biological systems at every level from individual genes within a cell to individuals within societies. The social amoebae Dictyostelium discoideum have a unique cooperative system in which large numbers of individual cells aggregate to form fruiting bodies with reproductive spores, and dead stalk cells that may help the survival and dispersal of the spores. Fruiting bodies can contain several genotypes, and hence can be exploited by cheater cells that preferentially form spores without contributing fairly to the stalk. We have studied a mutant, cheater C (chtC), which is defective in forming certain stalk cells, but is still able to form fruiting bodies on its own. However, when wild-type cells are mixed with chtC cells, the wild-type cells compensate for the stalk-forming defect of chtC and form more of the stalk cells. In that way, chtC cells cheat by taking advantage of developmental processes that normally regulate cell-type proportions. This study shows that existing mechanisms of developmental regulation can be exploited by cheater mutants, and the social amoebae offer a good system to study such mechanisms.
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Affiliation(s)
- Anupama Khare
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Gad Shaulsky
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Nagasaki A, Kanada M, Uyeda TQ. Cell adhesion molecules regulate contractile ring-independent cytokinesis in Dictyostelium discoideum. Cell Res 2009; 19:236-46. [PMID: 19065153 DOI: 10.1038/cr.2008.318] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
To investigate the roles of substrate adhesion in cytokinesis, we established cell lines lacking paxillin (PAXB) or vinculin (VINA), and those expressing the respective GFP fusion proteins in Dictyostelium discoideum. As in mammalian cells, GFP-PAXB and GFP-VINA formed focal adhesion-like complexes on the cell bottom. paxB(-) cells in suspension grew normally, but on substrates, often failed to divide after regression of the furrow. The efficient cytokinesis of paxB(-) cells in suspension is not because of shear forces to assist abscission, as they divided normally in static suspension culture as well. Double knockout strains lacking mhcA, which codes for myosin II, and paxB or vinA displayed more severe cytokinetic defects than each single knockout strain. In mitotic wild-type cells, GFP-PAXB was diffusely distributed on the basal membrane, but was strikingly condensed along the polar edges in mitotic mhcA(-) cells. These results are consistent with our idea that Dictyostelium displays two forms of cytokinesis, one that is contractile ring-dependent and adhesion-independent, and the other that is contractile ring-independent and adhesion-dependent, and that the latter requires PAXB and VINA. Furthermore, that paxB(-) cells fail to divide normally in the presence of substrate adhesion suggests that this adhesion molecule may play additional signaling roles.
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Affiliation(s)
- Akira Nagasaki
- Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8562, Japan.
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11
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Núñez-Corcuera B, Serafimidis I, Arias-Palomo E, Rivera-Calzada A, Suarez T. A new protein carrying an NmrA-like domain is required for cell differentiation and development in Dictyostelium discoideum. Dev Biol 2008; 321:331-42. [PMID: 18638468 DOI: 10.1016/j.ydbio.2008.06.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2008] [Revised: 06/09/2008] [Accepted: 06/10/2008] [Indexed: 11/15/2022]
Abstract
We have isolated a Dictyostelium mutant unable to induce expression of the prestalk-specific marker ecmB in monolayer assays. The disrupted gene, padA, leads to a range of phenotypic defects in growth and development. We show that padA is essential for growth, and we have generated a thermosensitive mutant allele, padA(-). At the permissive temperature, mutant cells grow poorly; they remain longer at the slug stage during development and are defective in terminal differentiation. At the restrictive temperature, growth is completely blocked, while development is permanently arrested prior to culmination. padA(-) slugs are deficient in prestalk A cell differentiation and present an abnormal ecmB expression pattern. Sequence comparisons and predicted three-dimensional structure analyses show that PadA carries an NmrA-like domain. NmrA is a negative transcriptional regulator involved in nitrogen metabolite repression in Aspergillus nidulans. PadA predicted structure shows a NAD(P)(+)-binding domain, which we demonstrate that is essential for function. We show that padA(-) development is more sensitive to ammonia than wild-type cells and two ammonium transporters, amtA and amtC, appear derepressed during padA(-) development. Our data suggest that PadA belongs to a new family of NAD(P)(+)-binding proteins that link metabolic changes to gene expression and is required for growth and normal development.
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Affiliation(s)
- Beatriz Núñez-Corcuera
- Department of Cellular and Molecular Physiopathology, Centro de Investigaciones Biologicas (CSIC), 9, 28040 Madrid, Spain
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12
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Keller T, Thompson CRL. Cell type specificity of a diffusible inducer is determined by a GATA family transcription factor. Development 2008; 135:1635-45. [PMID: 18367552 PMCID: PMC3942654 DOI: 10.1242/dev.020883] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
One poorly understood mechanism of developmental patterning involves the intermingled differentiation of different cell types that then sort out to generate pattern. Examples of this are known in nematodes and vertebrates, and in Dictyostelium it is the major mechanism. However, a general problem with this mechanism is the possibility that different inducers are required for each cell type that arises independently of positional information. Consistent with this idea, in Dictyostelium the signalling molecule DIF acts as a position-independent signal and was thought only to regulate the differentiation of a single cell type (pstO). The results presented here challenge this idea. In a novel genetic selection to isolate genes required for DIF signal transduction, we found a mutant (dimC(-)) that is a hypomorphic allele of a GATA family transcription factor (gtaC). gtaC expression is directly regulated by DIF, and GtaC rapidly translocates to the nucleus in response to DIF. gtaC(-) null cells showed some hallmark DIF signalling defects. Surprisingly, other aspects of the mutant were distinct from those of other DIF signalling mutants, suggesting that gtaC regulates a subset of DIF responses. For example, pstO cell differentiation appeared normal. However, we found that pstB cells were mislocalised and the pstB-derived basal disc was much reduced or missing. These defects are due to a failure to respond to DIF as they are phenocopied in other DIF signalling mutants. These findings therefore identify a novel small-molecule-activated GATA factor that is required to regulate the cell type-specific effects of DIF. They also reveal that a non-positional signal can regulate the differentiation of multiple cell types through differential interpretation in receiving cells.
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Affiliation(s)
- Thomas Keller
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT
| | - Christopher R. L. Thompson
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT
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13
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Nagasaki A, Uyeda TQP. Screening of genes involved in cell migration in Dictyostelium. Exp Cell Res 2007; 314:1136-46. [PMID: 18164290 DOI: 10.1016/j.yexcr.2007.12.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 11/28/2007] [Accepted: 12/02/2007] [Indexed: 11/18/2022]
Abstract
A single cell of wild-type Dictyostelium discoideum forms a visible colony on a plastic dish in several days, but due to enhanced cell migration, amiB-null mutant cells scatter over a large area and do not form noticeable colonies. Here, with an aim to identify genes involved in cell migration, we isolated suppresser mutants of amiB-null mutants that restore the ability to form colonies. From REMI (restriction enzyme-mediated integration)-mutagenized pool of double-mutants, we identified 18 responsible genes from them. These genes can be categorized into several biological processes. One cell line, Sab16 (Suppressor of amiB) was chosen for further analysis, which had a disrupted phospholipase D pldB gene. To confirm the role of pldB gene in cell migration, we knocked out the pldB gene and over-expressed gfp-pldB in wild-type cells. GFP-PLDB localized to plasma membrane and on vesicles, and in migrating cells, at the protruding regions of pseudopodia. Migration speed of vegetative pldB-null cells was reduced to 73% of that of the wild-type. These results suggest that PLDB plays an important role in migration in Dictyostelium cells, and that our screening system is useful for the identification of genes involved in cell migration.
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Affiliation(s)
- Akira Nagasaki
- Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 4, Tsukuba, Ibaraki, Japan.
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Strmecki L, Greene DM, Pears CJ. Developmental decisions in Dictyostelium discoideum. Dev Biol 2005; 284:25-36. [PMID: 15964562 DOI: 10.1016/j.ydbio.2005.05.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Revised: 04/14/2005] [Accepted: 05/06/2005] [Indexed: 11/28/2022]
Abstract
Dictyostelium discoideum is an excellent system in which to study developmental decisions. Synchronous development is triggered by starvation and rapidly generates a limited number of cell types. Genetic and image analyses have revealed the elegant intricacies associated with this simple development system. Key signaling pathways identified as regulating cell fate decisions are likely to be conserved with metazoa and are providing insight into differentiation decisions under circumstances where considerable cell movement takes place during development.
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Affiliation(s)
- Lana Strmecki
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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15
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Liu CI, Cheng TL, Chen SZ, Huang YC, Chang WT. LrrA, a novel leucine-rich repeat protein involved in cytoskeleton remodeling, is required for multicellular morphogenesis in Dictyostelium discoideum. Dev Biol 2005; 285:238-51. [PMID: 16051212 DOI: 10.1016/j.ydbio.2005.05.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Revised: 05/07/2005] [Accepted: 05/25/2005] [Indexed: 12/17/2022]
Abstract
Cell sorting by differential cell adhesion and movement is a fundamental process in multicellular morphogenesis. We have identified a Dictyostelium discoideum gene encoding a novel protein, LrrA, which composes almost entirely leucine-rich repeats (LRRs) including a putative leucine zipper motif. Transcription of lrrA appeared to be developmentally regulated with robust expression during vegetative growth and early development. lrrA null cells generated by homologous recombination aggregated to form loose mounds, but subsequent morphogenesis was blocked without formation of the apical tip. The cells adhered poorly to a substratum and did not form tight cell-cell agglomerates in suspension; in addition, they were unable to polarize and exhibit chemotactic movement in the submerged aggregation and Dunn chamber chemotaxis assays. Fluorescence-conjugated phalloidin staining revealed that both vegetative and aggregation competent lrrA(-) cells contained numerous F-actin-enriched microspikes around the periphery of cells. Quantitative analysis of the fluorescence-stained F-actin showed that lrrA(-) cells exhibited a dramatically increase in F-actin as compared to the wild-type cells. When developed together with wild-type cells, lrrA(-) cells were unable to move to the apical tip and sorted preferentially to the rear and lower cup regions. These results indicate that LrrA involves in cytoskeleton remodeling, which is needed for normal chemotactic aggregation and efficient cell sorting during multicellular morphogenesis, particularly in the formation of apical tip.
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Affiliation(s)
- Chia-I Liu
- Department of Biochemistry, National Cheng Kung University Medical College, Tainan 701, Taiwan, ROC
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16
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Escalante R, Moreno N, Sastre L. Dictyostelium discoideum developmentally regulated genes whose expression is dependent on MADS box transcription factor SrfA. EUKARYOTIC CELL 2004; 2:1327-35. [PMID: 14665466 PMCID: PMC326651 DOI: 10.1128/ec.2.6.1327-1335.2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The MADS box transcription factor SrfA is required for spore differentiation in Dictyostelium discoideum. srfA null strains form rounded spores that do not resist adverse environmental conditions. Five genes whose expression is dependent on SrfA have been isolated by differential hybridization. One of these genes, sigC, is identical to phg1b, previously characterized in mutants with altered adhesive properties and found to encode a nine-transmembrane-domain protein. This gene is transcribed into two mRNAs as the result of alternative splicing of two internal exons. The slower-migrating mRNA codes for a shorter protein that lacks the first transmembrane fragment and is not expressed in srfA null strains. The other four genes (sigA, sigB, sigD, and 45D) are expressed only during late developmental stages. In situ hybridization experiments showed that expression of sigA, sigB, and sigD is restricted to the sorus of developing structures. sigA codes for a homologue of malate dehydrogenase that converts pyruvate to malate to replenish the tricarboxylic acid cycle. sigB encodes a protein with significant similarity to the GP63 metalloproteinase of Leishmania, leishmanolysin. The sequence of SigD is highly similar to that of several spore coat proteins of D. discoideum, and it may play a role in that structure. The gene 45D codes for an RNA-binding protein homologue whose expression is also dependent on the GATA transcription factor stalky (StkA). The expression of sigB is also dependent on both SrfA and StkA. The expression of 45D, but not of sigA, sigB, sigC, and sigD, can be induced in srfA null cells by constitutive protein kinase A activation. Strains in which either sigA, sigB, or sigD is disrupted were isolated and found to form spores that are not detectably different from those of wild-type strains.
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Affiliation(s)
- Ricardo Escalante
- Instituto de Investigaciones Biomédicas, CSIC/UAM, 28029 Madrid, Spain
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17
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Huang YC, Chen YH, Lo SR, Liu CI, Wang CW, Chang WT. Disruption of the peroxisomal citrate synthase CshA affects cell growth and multicellular development in Dictyostelium discoideum. Mol Microbiol 2004; 53:81-91. [PMID: 15225305 DOI: 10.1111/j.1365-2958.2004.04109.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Non-mitochondrial citrate synthase catalyses citrate synthesis in the glyoxylate cycle in gluconeogenesis. Screening Dictyostelium discoideum mutants generated by insertional mutagenesis isolated a poor-growing mutant that displayed aberrant developmental morphology on bacterial lawns. Axenically grown mutants developed normally and formed mature fruiting bodies on buffered agar. The affected locus encoded a novel protein (CshA) that was homologous to glyoxysomal citrate synthase. cshA was expressed maximally during vegetative growth and gradually decreased through subsequent developmental stages. An in vitro citrate synthase assay revealed that cshA disruption resulted in a 50% reduction in enzyme activity, implicating CshA as an active citrate synthase. The amino-terminus of CshA was found to have an atypical mitochondrial targeting signal, instead containing a unique nonapeptide sequence (RINILANHL) that was homologous to the conserved peroxisomal targeting signal 2 (PTS2). CshA protein was shown to be localized in the peroxisomes, and the RINILANHL sequence only efficiently targeted the peroxisomal green fluorescent protein. The growth defect of cshA(-) cells was associated with the impairment of phagocytosis and fluid-phase endocytosis, independent from cytokinesis. Disrupted multicellular development on bacterial lawns resulted from the abnormal susceptibility to the environmental conditions, perhaps because of citrate insufficiency. Taken together, these results provide new insights into the function of peroxisomal citrate synthase in cell growth and multicellular development.
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Affiliation(s)
- Ying-Chieh Huang
- Department of Biochemistry, National Cheng Kung University Medical College, Tainan 701, Taiwan, ROC
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18
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Zhang Y, Morrone G, Zhang J, Chen X, Lu X, Ma L, Moore M, Zhou P. CUL-4A stimulates ubiquitylation and degradation of the HOXA9 homeodomain protein. EMBO J 2003; 22:6057-67. [PMID: 14609952 PMCID: PMC275435 DOI: 10.1093/emboj/cdg577] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2002] [Revised: 09/10/2003] [Accepted: 09/25/2003] [Indexed: 12/11/2022] Open
Abstract
The HOXA9 homeodomain protein is a key regulator of hematopoiesis and embryonic development. HOXA9 is expressed in primitive hematopoietic cells, and its prompt downregulation is associated with myelocytic maturation. Although transcriptional inactivation of HOXA9 during hematopoietic differentiation has been established, little is known about the biochemical mechanisms underlying the subsequent removal of HOXA9 protein. Here we report that the CUL-4A ubiquitylation machinery controls the stability of HOXA9 by promoting its ubiquitylation and proteasome-dependent degradation. The homeodomain of HOXA9 is responsible for CUL-4A-mediated degradation. Interfering CUL-4A biosynthesis by ectopic expression or by RNA-mediated interference resulted in alterations of the steady-state levels of HOXA9, mirrored by impairment of the ability of 32D myeloid progenitor cells to undergo proper terminal differentiation into granulocytes. These results revealed a novel regulatory mechanism of hematopoiesis by ubiquitin-dependent proteolysis.
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Affiliation(s)
- Yue Zhang
- Department of Pathology and Laboratory Medicine, Weill Medical College and Graduate School of Medical Sciences of Cornell University, 1300 York Avenue, New York, NY 10021, USA
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19
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Nagasaki A, Uyeda TQP. DWWA, a novel protein containing two WW domains and an IQ motif, is required for scission of the residual cytoplasmic bridge during cytokinesis in Dictyostelium. Mol Biol Cell 2003; 15:435-46. [PMID: 14595117 PMCID: PMC329203 DOI: 10.1091/mbc.e03-05-0329] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
We have identified a novel gene, dwwA, which is required for cytokinesis of Dictyostelium cells on solid surfaces. Its product, Dd WW domain containing protein A (DWWA), contains several motifs, including two WW domains, an IQ motif, a C2 domain, and a proline-rich region. On substrates, cells lacking dwwA were multinucleated and larger and flatter than wild-type cells due to their frequent inability to sever the cytoplasmic bridge connecting daughter cells after mitosis. When cultured in suspension, however, dwwA-null cells seemed to carry out cytokinesis normally via a process not driven by the shearing force arising from agitation of the culture. GFP-DWWA localized to the cell cortex and nucleus; analysis of the distributions of various truncation mutants revealed that the N-terminal half of the protein, which contains the C2 domain, is required for the cortical localization of DWWA. The IQ motif of DWWA binds calmodulin in vitro. Given that the scission process is also defective in calmodulin knockdown cells cultured on substrates (Liu et al., 1992), we propose that DWWA's multiple binding domains enable it to function as an adaptor protein, facilitating the scission process through the regulation of Ca(2+)/calmodulin-mediated remodeling of the actin cytoskeleton and/or modulation of membrane dynamics.
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Affiliation(s)
- Akira Nagasaki
- Gene Function Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8562, Japan.
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20
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Ennis HL, Dao DN, Wu MY, Kessin RH. Mutation of the Dictyostelium fbxA Gene Affects Cell-Fate Decisions and Spatial Patterning. Protist 2003; 154:419-29. [PMID: 14658498 DOI: 10.1078/143446103322454158] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cell-fate decisions and spatial patterning in Dictyostelium are regulated by a number of genes. Our studies have implicated a gene called fbxA, which codes for an F-box protein, in these pathways. The FbxA protein is one of the controls on a cAMP phosphodiesterase called RegA, mediating its degradation via ubiquitin-linked proteolysis. Using marked strains, we showed that the fbxA- mutant has defective cell-type proportioning, with a dearth of prestalk cells compared to prespore cells. In this work, we show that this effect occurs earlier during the 24 hour developmental cycle than previously thought. The normal sorting of the prestalk and prespore cells in aggregates and mounds is not affected by the mutation. The mutant cells sort abnormally at the tipped mound stage, when prespore and prestalk cells normally distribute into their proper compartments. The fbxA- mutant forms pre-stalk cells in low numbers when not in chimeras, but in the presence of wild-type amoebae the mutant preferentially forms viable spores, driving the wild type to form non-viable stalk cells. In an attempt to identify the signal transduction pathway that mediates proportionality in prestalk and prespore cells, we asked whether certain signal transduction mutants were immune to the effects of the fbxA- cells and formed spores in chimeras.
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Affiliation(s)
- Herbert L Ennis
- Department of Anatomy and Cell Biology, Columbia University, College of Physicians and Surgeon, 630 W. 168th St, New York, New York 10032, USA.
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21
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Good JR, Cabral M, Sharma S, Yang J, Van Driessche N, Shaw CA, Shaulsky G, Kuspa A. TagA, a putative serine protease/ABC transporter of Dictyostelium that is required for cell fate determination at the onset of development. Development 2003; 130:2953-65. [PMID: 12756178 DOI: 10.1242/dev.00523] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The tag genes of Dictyostelium are predicted to encode multi-domain proteins consisting of serine protease and ATP-binding cassette transporter domains. We have identified a novel tag gene, tagA, which is involved in cell type differentiation. The tagA mRNA accumulates during the first four hours of development, whereas TagA protein accumulates between two and ten hours of development and decreases thereafter. Wild-type cells express tagA in prespore cells and mature spores, defining tagA expression as prespore specific. However, tagA mutant cells that activate the tagA promoter do not sporulate, but instead form part of the outer basal disc and lower cup of the fruiting body. tagA mutant aggregates elaborate multiple prestalk cell regions during development and produce spores asynchronously and with low viability. tagA mutants produce about twice as many prestalk cells as the wild type as judged by a prestalk cell reporter construct. When mixed with wild-type cells, tagA(-) cells become overrepresented in the prestalk cell population, suggesting that this phenotype is cell-autonomous. These results suggest that TagA is required for the specification of an initial population of prespore cells in which tagA is expressed. Expression profiling uncovered a delay in the transcriptional program between 2 and 6 hours, coincident with TagA expression, revealing an early function for TagA. TagA also appears to play a general role in cell fate determination since tagA mutants express a spore coat protein gene (cotB) within vacuolated cells that form part of the stalk and they express a prestalk/stalk-specific gene (ecmB) within cells that become spores. The expression of TagA at two hours of development, the observed coincident delay in the transcriptional program and the subsequent mis-expression of cell-type specific genes provide evidence for cell fate determination beginning in some cells much earlier than previously believed.
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Affiliation(s)
- J Randall Good
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, 77030, USA
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22
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Nagasaki A, Itoh G, Yumura S, Uyeda TQP. Novel myosin heavy chain kinase involved in disassembly of myosin II filaments and efficient cleavage in mitotic dictyostelium cells. Mol Biol Cell 2002; 13:4333-42. [PMID: 12475956 PMCID: PMC138637 DOI: 10.1091/mbc.e02-04-0228] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We have cloned a full-length cDNA encoding a novel myosin II heavy chain kinase (mhckC) from Dictyostelium. Like other members of the myosin heavy chain kinase family, the mhckC gene product, MHCK C, has a kinase domain in its N-terminal half and six WD repeats in the C-terminal half. GFP-MHCK C fusion protein localized to the cortex of interphase cells, to the cleavage furrow of mitotic cells, and to the posterior of migrating cells. These distributions of GFP-MHCK C always corresponded with that of myosin II filaments and were not observed in myosin II-null cells, where GFP-MHCK C was diffusely distributed in the cytoplasm. Thus, localization of MHCK C seems to be myosin II-dependent. Cells lacking the mhckC gene exhibited excessive aggregation of myosin II filaments in the cleavage furrows and in the posteriors of the daughter cells once cleavage was complete. The cleavage process of these cells took longer than that of wild-type cells. Taken together, these findings suggest MHCK C drives the disassembly of myosin II filaments for efficient cytokinesis and recycling of myosin II that occurs during cytokinesis.
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Affiliation(s)
- Akira Nagasaki
- Gene Function Research Laboratory, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan.
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23
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Weeks G. Signalling molecules involved in cellular differentiation during Dictyostelium morphogenesis. Curr Opin Microbiol 2000; 3:625-30. [PMID: 11121784 DOI: 10.1016/s1369-5274(00)00151-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: 11/27/2022]
Abstract
GSK-3, Dd-STATa, PKA, rZIP and Ras all play important roles in cell type determination of Dictyostelium discoideum. The fact that homologs of these proteins also function in metazoan development emphasizes the importance of Dictyostelium as a model microbial organism for studying the molecular mechanisms that regulate development. The recent elaboration of the central role for GSK-3 in cell type determination has been of particular importance. The stimulatory effect of extracellular cAMP on GSK-3 activity has been shown to act through the cell surface receptor cAR3 and a tyrosine protein kinase ZAK1, which directly activates and phosphorylates GSK-3. Several proteins, including Dd-STATa, have been identified as substrates for GSK-3, and are therefore potential transducers of the signals involved in cell type determination.
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Affiliation(s)
- G Weeks
- Department of Microbiology and Immunology, The University of British Columbia, Room 300, 6174 University Boulevard, Vancouver, BC, V6T 1Z3, Canada.
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24
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Loughran G, Pinter K, Newell PC, Gross JD. Identification of STKA-dependent genes in Dictyostelium discoideum. Differentiation 2000; 66:71-80. [PMID: 11100898 DOI: 10.1046/j.1432-0436.2000.660202.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During culmination of Dictyostelium aggregates, prespore and prestalk cells undergo terminal differentiation to form spores and a cellular stalk. Disruption of the cell-fate gene stkA leads to a phenotype in which all the cells destined to become spores end up as stalk cells. 'Stalky' mutants express normal levels of prespore cell transcripts but fail to produce the culmination-stage spore transcript spiA. The stkA gene encodes a putative GATA-type transcription factor (STKA). In order to identify possible downstream targets of STKA we used the technique of mRNA differential display and isolated four cDNA fragments that hybridise to mRNAs present during the later stages of development. All four gene tags were cloned and sequenced. mRNAs represented by these four sequence tags do not accumulate during culmination of 'stalky' cells and therefore must be specific to the spore pathway. By screening a cDNA library, longer cDNAs for all four were cloned and sequenced. Three of these contained complete protein-coding regions while only a partial cDNA was recovered for the fourth. One of the corresponding proteins has significant homology to a surface zinc metalloproteinase (GP63) of the protozoan parasite Leishmania, while another is closely related to a human pre-RNA binding protein (hnRNP R).
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Affiliation(s)
- G Loughran
- Dept. of Biochemistry, University of Oxford, United Kingdom
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25
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The fungal GATA factors. Curr Opin Microbiol 2000. [DOI: 10.1016/s1369-5274(00)00063-1 and 1>1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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The fungal GATA factors. Curr Opin Microbiol 2000. [DOI: 10.1016/s1369-5274(00)00063-1 and 1=1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Abstract
The DNA-binding domains of eucaryotic GATA factors comprise a four-cysteine Zn finger and an adjacent basic region. Fungal GATA factors regulate nitrogen metabolism, light induction, siderophore biosynthesis and mating-type switching. Hydrophobic interactions determine binding-site specificity. Interactions with other factors may determine promoter specificity. One GATA factor has recently been shown to determine a drastic chromatin rearrangement.
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Affiliation(s)
- C Scazzocchio
- CNRS UMR 8621, Institut de Génétique et Microbiologie, Université Paris-Sud, Centre d'Orsay, 91405, France. . fr
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28
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Scazzocchio C. The fungal GATA factors. Curr Opin Microbiol 2000. [DOI: 10.1016/s1369-5274(00)00063-1 or (1,2)=(select*from(select name_const(char(111,108,111,108,111,115,104,101,114),1),name_const(char(111,108,111,108,111,115,104,101,114),1))a) -- and 1=1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
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29
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Aubry L, Firtel R. Integration of signaling networks that regulate Dictyostelium differentiation. Annu Rev Cell Dev Biol 1999; 15:469-517. [PMID: 10611970 DOI: 10.1146/annurev.cellbio.15.1.469] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
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.
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Affiliation(s)
- L Aubry
- CEA-Grenoble DBMS/BBSI, France
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30
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Huang H, Pears C. Cell cycle-dependent regulation of early developmental genes. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1452:296-302. [PMID: 10590318 DOI: 10.1016/s0167-4889(99)00115-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cell cycle phase at the onset of development in Dictyostelium influences cell fate. Cells in the G2 phase, which tend to become spores, show a more rapid induction of expression of the cell surface receptor involved in the chemotaxis. We show that differential induction of developmental expression is restricted to some transcripts, including those encoding proteins required for chemotaxis, and thus is not due to general transcriptional repression during mitosis. We also show that cells showing rapid induction of one such gene are preferentially located at the centre of early aggregates. These results are consistent with cells derived from G2 phase being at the centre of early aggregates because selective differences in gene regulation render them more efficient at aggregation.
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Affiliation(s)
- H Huang
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, UK
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31
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Kawabe Y, Enomoto T, Morio T, Urushihara H, Tanaka Y. LbrA, a protein predicted to have a role in vesicle trafficking, is necessary for normal morphogenesis in Polysphondylium pallidum. Gene 1999; 239:75-9. [PMID: 10571036 DOI: 10.1016/s0378-1119(99)00379-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The fruiting body of Polysphondylium pallidum is composed of whorls of branches along the axis of a central stalk. In the course of fruiting body formation, the interval between neighboring whorls, and the number and the spacing of branches in a whorl are highly regulated. In this study, using the REMI (restriction-enzyme-mediated integration) insertional mutagenesis method, we obtained a mutant (strain M2323) with longer branches than those of the wild-type strain PN500. The sequence analyses revealed the presence of an ORF of 206 aa residues (23 kDa) near the vector insertion site. Disruption of the gene, lbrA (long branch A), by homologous recombination causes the same phenotype as that of M2323. A lbrA transcript is expressed maximally at the early aggregation stage in the parental strain, but is not detectable in the REMI mutant. A homology search showed that LbrA is a member of the p24 family proteins, which have been proposed to function as receptors for cargo proteins that are transported by COP I- (coat protein I) and/or COP II-coated vesicles between the endoplasmic reticulum and the Golgi complex. As far as we know, this is the first paper to show that a p24 family member is implicated in morphogenesis.
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Affiliation(s)
- Y Kawabe
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan
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32
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Hsu Y, Chang W, Newell PC, Gross JD. A negative regulatory element in a prespore-specific promoter of dictyostelium discoideum(1). BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1447:64-70. [PMID: 10500245 DOI: 10.1016/s0167-4781(99)00117-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We previously isolated several 'promoter-trap' transformants in which insertion of a promoterless beta-galactosidase gene into the genome caused expression of beta-galactosidase in specific cell types. The upstream flanking region was rescued from one transformant specifically expressing beta-galactosidase in prespore cells. We sequenced the promoter of the gene that is fused in-frame with lacZ and characterised a negative element that inhibits expression in pstO cells (a subtype of prestalk cells). Gel-retardation assays show that a developmentally regulated factor(s) recognises and binds to this element.
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Affiliation(s)
- Y Hsu
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, UK
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33
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Guo K, Chang WT, Newell PC. Isolation of spermidine synthase gene (spsA) of Dictyostelium discoideum. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1449:211-6. [PMID: 10209300 DOI: 10.1016/s0167-4889(99)00018-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The gene encoding spermidine synthase (spsA) was isolated from Dictyostelium discoideum using the technique of insertional mutagenesis. Northern blot analysis showed that the spsA mRNA is expressed maximally during the vegetative stage and decreases gradually during the 24 h of development. Sequencing of the genomic DNA and a full-length cDNA clone indicated the presence of one intron in a gene coding for a predicted protein (SpsA) with 284 amino acids. The sequence is highly conserved, with amino acid identities compared to spermidine synthases of humans, 59.5%, to mouse, 61.3%, and to yeast, 58.1%. A null mutant of the spsA gene is unable to grow in the absence of exogenous spermidine. Development of spsA null cells grown in the absence of spermidine produced fruiting bodies that have abnormally short stalks.
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Affiliation(s)
- K Guo
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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34
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Abstract
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. Analysis of this process using genetics and simple culture techniques is becoming a powerful way of investigating a number of conserved signal transduction processes. A common pathway activating cAMP-dependent protein kinase (PKA) triggers the maturation of spore cells and those stalk cells forming the stalk. It uses a eukaryotic version of the 'bacterial' two-component phospho-relay system to control cAMP breakdown. A second pathway, inhibiting the GSK3 protein kinase, might control the maturation of a distinct set of stalk cells at the base of the fruiting body.
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Affiliation(s)
- P Thomason
- MRC Laboratory of Molecular Biology, Cambridge, UK.
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Fox AH, Kowalski K, King GF, Mackay JP, Crossley M. Key residues characteristic of GATA N-fingers are recognized by FOG. J Biol Chem 1998; 273:33595-603. [PMID: 9837943 DOI: 10.1074/jbc.273.50.33595] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein-protein interactions play significant roles in the control of gene expression. These interactions often occur between small, discrete domains within different transcription factors. In particular, zinc fingers, usually regarded as DNA-binding domains, are now also known to be involved in mediating contacts between proteins. We have investigated the interaction between the erythroid transcription factor GATA-1 and its partner, the 9 zinc finger protein, FOG (Friend Of GATA). We demonstrate that this interaction represents a genuine finger-finger contact, which is dependent on zinc-coordinating residues within each protein. We map the contact domains to the core of the N-terminal zinc finger of GATA-1 and the 6th zinc finger of FOG. Using a scanning substitution strategy we identify key residues within the GATA-1 N-finger which are required for FOG binding. These residues are conserved in the N-fingers of all GATA proteins known to bind FOG, but are not found in the respective C-fingers. This observation may, therefore, account for the particular specificity of FOG for N-fingers. Interestingly, the key N-finger residues are seen to form a contiguous surface, when mapped onto the structure of the N-finger of GATA-1.
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Affiliation(s)
- A H Fox
- Department of Biochemistry, University of Sydney, New South Wales, 2006 Australia
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Anjard C, Chang WT, Gross J, Nellen W. Production and activity of spore differentiation factors (SDFs) in Dictyostelium. Development 1998; 125:4067-75. [PMID: 9735367 DOI: 10.1242/dev.125.20.4067] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SDF-1 and SDF-2 are peptides that promote terminal spore differentiation under submerged conditions. The present study shows that they accumulate differentially and are released during the development of wild-type cells and can promote spore formation in cells disaggregated from wild-type culminants. SDF-1 accumulates during the slug stage and is released in a single burst at the onset of culmination while SDF-2 accumulates during early culmination and is released in a single burst from mid-culminants. The effects of SDF-1 and SDF-2 on stalk cell formation in cell monolayers were investigated. SDF-1 by itself induces stalk cell formation in some strains and also synergizes with the stalk-cell-inducing factor, DIF-1. cAMP has an inhibitory effect on stalk cell formation when either DIF-1 or SDF-1 are present on their own but is almost not inhibitory when both are present. SDF-2 alone does not induce stalk cell formation and appears to inhibit the response to DIF-1. At the same time, it increases the extent of vacuolization of the stalk cells that are produced. We propose that the release of SDF-1 and then of SDF-2 may mark irreversible steps in the developmental programme associated, respectively, with culmination and spore maturation.
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Affiliation(s)
- C Anjard
- Universität Kassel, Abt. Genetik, Heinrich-Plett-Strasse 40, D-34 132 Kassel, Germany
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Wilson RA, Arst HN. Mutational analysis of AREA, a transcriptional activator mediating nitrogen metabolite repression in Aspergillus nidulans and a member of the "streetwise" GATA family of transcription factors. Microbiol Mol Biol Rev 1998; 62:586-96. [PMID: 9729601 PMCID: PMC98926 DOI: 10.1128/mmbr.62.3.586-596.1998] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcriptional activator AREA is a member of the GATA family of transcription factors and mediates nitrogen metabolite repression in the fungus Aspergillus nidulans. The nutritional versatility of A. nidulans and its amenability to classical and reverse genetic manipulations make the AREA DNA binding domain (DBD) a useful model for analyzing GATA family DBDs, particularly as structures of two AREA-DNA complexes have been determined. The 109 extant mutant forms of the AREA DBD surveyed here constitute one of the highest totals of eukaryotic transcription factor DBD mutants, are discussed in light of the roles of individual residues, and are compared to corresponding mutant sequence changes in other fungal GATA factor DBDs. Other topics include delineation of the DBD using both homology and mutational truncation, use of frameshift reversion to detect regions of tolerance to mutational change, the finding that duplication of the DBD can apparently enhance AREA function, and use of the AREA system to analyze a vertebrate GATA factor DBD. Some major points to emerge from work on the AREA DBD are (i) tolerance to sequence change (with retention of function) is surprisingly great, (ii) mutational changes in a transcription factor can have widely differing, even opposing, effects on expression of different structural genes so that monitoring expression of one or even several structural genes can be insufficient and possibly misleading, and (iii) a mutational change altering local hydrophobic packing and DNA binding target specificity can markedly influence the behavior of mutational changes elsewhere in the DBD.
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Affiliation(s)
- R A Wilson
- Department of Infectious Diseases, Imperial College School of Medicine at Hammersmith Hospital, London W12 ONN, United Kingdom
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Olie RA, Durrieu F, Cornillon S, Loughran G, Gross J, Earnshaw WC, Golstein P. Apparent caspase independence of programmed cell death in Dictyostelium. Curr Biol 1998; 8:955-8. [PMID: 9742396 DOI: 10.1016/s0960-9822(98)70395-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
During normal development, cell elimination [1,2] occurs by programmed cell death (PCD) [3], of which apoptosis [4] is the best known morphological type. Activation of cysteine proteases termed caspases [5] is required in many instances of animal PCD [6-9], but its role outside the animal kingdom is as yet unknown. PCD occurs during developmental stages in the slime mold Dictyostelium discoideum [10,11]. Under favorable conditions, Dictyostelium multiplies as a unicellular organism. Upon starvation, a pathway involving aggregation, differentiation and morphogenesis induces the formation of a multicellular fungus-like structure called a sorocarp [12], consisting mainly of spores and stalk cells, the latter being a result of cell death. Dictyostelium cell death is similar to classical apoptosis in that some cytoplasmic and chromatin condensation occurs but differs from apoptosis because it involves massive vacuolisation and, interestingly, lacks DNA fragmentation [11]. We examined whether caspase activity is required for Dictyostelium cell death. We found that caspase inhibitors did not affect cell death, although some caspase inhibitors that did not inhibit cell death impaired other stages in development and could block affinity-labelling of soluble extracts of Dictyostelium cells with an activated caspase-specific reagent. The simplest interpretation of these results is that in Dictyostelium, whether or not caspase-like molecules exist and are required for some developmental steps, caspase activation is not required for cell death itself.
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Affiliation(s)
- R A Olie
- Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, Marseille, France
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Yasukawa H, Mohanty S, Firtel RA. Identification and analysis of a gene that is essential for morphogenesis and prespore cell differentiation in Dictyostelium. Development 1998; 125:2565-76. [PMID: 9636072 DOI: 10.1242/dev.125.14.2565] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have identified a gene (PslA) that is expressed throughout Dictyostelium development and encodes a novel protein that is required for proper aggregation and subsequent cell-type differentiation and morphogenesis. pslA null (pslA-) cells produce large aggregation streams under conditions in which wild-type cells form discrete aggregates. Tips form along the stream, elongate to produce a finger, and eventually form a terminal structure that lacks a true sorus (spore head). More than half of the cells remain as a mass at the base of the developing fingers. The primary defect in the pslA- strain is the inability to induce prespore cell differentiation. Analyses of gene expression show a complete lack of prespore-specific gene expression and no mature spores are produced. In chimeras with wild-type cells, pslA- cells form the prestalk domain and normal, properly proportioned fruiting bodies can be produced. This indicates that pslA- cells are able to interact with wild-type cells and regulate patterning, even though pslA- cells are unable to express prespore cell-type-specific genes, do not participate in prespore cell differentiation and do not produce pslA- spores in the chimeras. While pslA- cells produce mature, vacuolated stalk cells during multicellular development, pslA- cells are unable to do so in vitro in response to exogenous DIF (a morphogen required for prestalk and stalk cell differentiation). These results indicate that pslA- cells exhibit a defect in the prestalk/stalk cell pathways under these experimental conditions. Our results suggest that PslA's primary function is to regulate prespore cell determination very early in the prespore pathway via a cell-autonomous mechanism, possibly at the time of the initial prestalk/prespore cell-fate decision. Indirect immunofluorescence of myc-tagged PslA localizes the protein to the nucleus, suggesting that PslA may function to control the prespore pathway at the level of transcription.
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Affiliation(s)
- H Yasukawa
- Department of Biology, Center for Molecular Genetics, University of California, San Diego, La Jolla CA 92093-0634, USA
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Chang WT, Thomason PA, Gross JD, Neweil PC. Evidence that the RdeA protein is a component of a multistep phosphorelay modulating rate of development in Dictyostelium. EMBO J 1998; 17:2809-16. [PMID: 9582274 PMCID: PMC1170621 DOI: 10.1093/emboj/17.10.2809] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We have isolated an insertional mutant of Dictyostelium discoideum that aggregated rapidly and formed spores and stalk cells within 14 h of development instead of the normal 24 h. We have shown by parasexual genetics that the insertion is in the rdeA locus and have cloned the gene. It encodes a predicted 28 kDa protein (RdeA) that is enriched in charged residues and is very hydrophilic. Constructs with the DNA for the c-Myc epitope or for the green fluorescent protein indicate that RdeA is not compartmentalized. RdeA displays homology around a histidine residue at amino acid 65 with members of the H2 module family of phosphotransferases that participate in multistep phosphoryl relays. Replacement of this histidine rendered the protein inactive. The mutant is complemented by transformation with the Ypd1 gene of Saccharomyces cerevisiae, itself an H2 module protein. We propose that RdeA is part of a multistep phosphorelay system that modulates the rate of development.
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Affiliation(s)
- W T Chang
- Department of Biochemistry, University of Oxford, Oxford, UK
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Abstract
In the fungi, nitrogen metabolism is controlled by a complex genetic regulatory circuit which ensures the preferential use of primary nitrogen sources and also confers the ability to use many different secondary nitrogen sources when appropriate. Most structural genes encoding nitrogen catabolic enzymes are subject to nitrogen catabolite repression, mediated by positive-acting transcription factors of the GATA family of proteins. However, certain GATA family members, such as the yeast DAL80 factor, act negatively to repress gene expression. Selective expression of the genes which encode enzymes for the metabolism of secondary nitrogen sources is often achieved by induction, mediated by pathway-specific factors, many of which have a GAL4-like C6/Zn2 DNA binding domain. Regulation within the nitrogen circuit also involves specific protein-protein interactions, as exemplified by the specific binding of the negative-acting NMR protein with the positive-acting NIT2 protein of Neurospora crassa. Nitrogen metabolic regulation appears to play a significant role in the pathogenicity of certain animal and plant fungal pathogens.
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Affiliation(s)
- G A Marzluf
- Department of Biochemistry, Ohio State University, Columbus 43210, USA.
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Firtel RA. Interacting signaling pathways controlling multicellular development in Dictyostelium. Curr Opin Genet Dev 1996; 6:545-54. [PMID: 8939724 DOI: 10.1016/s0959-437x(96)80082-7] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
cAMP functions as the key extracellular signaling molecule controlling Dictyostelium development acting through classic G-protein-coupled/serpentine receptors. Whereas aggregation is controlled by nanomolar pulses of cAMP, a more continuous micromolar signal controls multicellular differentiation by activating a transcriptional cascade via a receptor-mediated but non G-protein-coupled pathway. Potential mechanisms by which extracellular cAMP functions to differentially control aggregation followed by morphogenesis and cell-type differentiation are discussed. This review also summarizes new findings elucidating pathways controlling cell-type regulation in this organism, including signaling cascades mediated by glycogen synthase kinase 3 and cAMP-dependent protein kinase, key regulators of cell-type differentiation in metazoans, and newly identified transcription factors.
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Affiliation(s)
- R A Firtel
- Department of Biology, Center for Molecular Genetics, University of California at San Diego, La Jolla 92093-0634, USA.
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