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Zhu X, Ricci-Tam C, Hager ER, Sgro AE. Self-cleaving peptides for expression of multiple genes in Dictyostelium discoideum. PLoS One 2023; 18:e0281211. [PMID: 36862626 PMCID: PMC9980757 DOI: 10.1371/journal.pone.0281211] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 01/18/2023] [Indexed: 03/03/2023] Open
Abstract
The social amoeba Dictyostelium discoideum is a model for a wide range of biological processes including chemotaxis, cell-cell communication, phagocytosis, and development. Interrogating these processes with modern genetic tools often requires the expression of multiple transgenes. While it is possible to transfect multiple transcriptional units, the use of separate promoters and terminators for each gene leads to large plasmid sizes and possible interference between units. In many eukaryotic systems this challenge has been addressed through polycistronic expression mediated by 2A viral peptides, permitting efficient, co-regulated gene expression. Here, we screen the most commonly used 2A peptides, porcine teschovirus-1 2A (P2A), Thosea asigna virus 2A (T2A), equine rhinitis A virus 2A (E2A), and foot-and-mouth disease virus 2A (F2A), for activity in D. discoideum and find that all the screened 2A sequences are effective. However, combining the coding sequences of two proteins into a single transcript leads to notable strain-dependent decreases in expression level, suggesting additional factors regulate gene expression in D. discoideum that merit further investigation. Our results show that P2A is the optimal sequence for polycistronic expression in D. discoideum, opening up new possibilities for genetic engineering in this model system.
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Affiliation(s)
- Xinwen Zhu
- Department of Biomedical Engineering, Boston University, Boston, MA, United States of America
- Biological Design Center, Boston University, Boston, MA, United States of America
| | - Chiara Ricci-Tam
- Department of Biomedical Engineering, Boston University, Boston, MA, United States of America
- Biological Design Center, Boston University, Boston, MA, United States of America
| | - Emily R. Hager
- Department of Biomedical Engineering, Boston University, Boston, MA, United States of America
- Biological Design Center, Boston University, Boston, MA, United States of America
| | - Allyson E. Sgro
- Department of Biomedical Engineering, Boston University, Boston, MA, United States of America
- Biological Design Center, Boston University, Boston, MA, United States of America
- * E-mail:
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2
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Transcription and processing of mitochondrial RNA in the human pathogen Acanthamoeba castellanii. Mitochondrion 2015; 23:25-31. [DOI: 10.1016/j.mito.2015.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 05/18/2015] [Accepted: 05/22/2015] [Indexed: 11/21/2022]
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3
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Le P, Fisher PR, Barth C. Transcription of the Dictyostelium discoideum mitochondrial genome occurs from a single initiation site. RNA (NEW YORK, N.Y.) 2009; 15:2321-2330. [PMID: 19861424 PMCID: PMC2779680 DOI: 10.1261/rna.1710309] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 09/18/2009] [Indexed: 05/28/2023]
Abstract
Transcription of the mitochondrial genome in Dictyostelium discoideum gives rise to eight major polycistronic RNA species that can be detected by Northern hybridization. In order to determine whether these transcripts could possibly derive from processing of even larger transcripts, reverse transcriptase polymerase chain reactions (RT-PCRs) were performed in an attempt to amplify the intervening regions between the eight major transcripts. All but one intervening region were successfully reverse transcribed and amplified, indicating that even larger transcripts existed and that the eight major transcripts detected previously may be the products of transcript processing. Southern hybridization analyses of DNA fragments representing the sequences between the eight major transcripts with in vitro capped mitochondrial RNA identified the 5' end of only one of the eight major transcripts as a genuine transcription start site. The ability to initiate transcription from DNA sequences upstream of the identified transcription initiation site was demonstrated in bacterial cells expressing the Dictyostelium mitochondrial RNA polymerase. We conclude that transcription of the Dictyostelium mitochondrial genome is initiated at a single site, generating a large polycistronic transcript that is very efficiently, probably cotranscriptionally processed into mature RNA species. This is the first report on a protist mitochondrial DNA that is, although much larger in size than its metazoan counterparts, transcribed from a single transcription initiation site.
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Affiliation(s)
- Phuong Le
- Department of Microbiology, La Trobe University, Bundoora, Victoria 3086, Australia
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4
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JACOBSON LISAM, BAND RNEAL. Genetic Heterogeneity in a Natural Population ofAcanthamoeba polyphagafrom Soil, an Isoenzyme Analysis1. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1987.tb03138.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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5
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Arasada R, Son H, Ramalingam N, Eichinger L, Schleicher M, Rohlfs M. Characterization of the Ste20-like kinase Krs1 of Dictyostelium discoideum. Eur J Cell Biol 2006; 85:1059-68. [PMID: 16842885 DOI: 10.1016/j.ejcb.2006.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Ste20-like kinases constitute a ubiquitous and expanding group of serine/threonine kinases, homologous to Ste20 in Saccharomyces cerevisiae. The social amoeba Dictyostelium discoideum contains at least 17 members of this kinase family, 13 from the germinal center kinase (GCK) subgroup and 4 p21-activated kinases (PAK). Here, we describe the kinase Krs1 which is encoded by the gene krsA, and phylogenetic analysis groups it into subfamily GCK-II together with human MST2 and MST1 or Hippo from Drosophila melanogaster. Significant similarities are found especially in the catalytic domain and in a short regulatory region (SARAH) which is thought to be important for protein/protein interactions. Northern blot analysis showed a single krsA transcript throughout development with an upregulation at 12h after the onset of starvation. The protein levels as detected with anti-Krs1 polyclonal antibodies revealed a similar pattern. Gel filtration experiments suggested that AX2 wild-type cells harbored multimeric forms of Krs1. In vitro phosphorylation assays with recombinant protein showed that the kinase exhibits autophosphorylation and accepts myelin basic protein and D. discoideum severin as substrates. A series of C-terminal deletions of Krs1 indicated that the regulatory domain in the C-terminal half contains inhibitory elements, and highlighted the importance of two predicted alpha-helices following subdomain XI of the classical catalytic domain. GFP-Krs1-overexpressing wild-type cells showed an enrichment of the kinase in the cortex, and motility of these cells during aggregation was reduced. Krs1 knockout strains exhibited only subtle differences to wild-type cells which suggests a certain redundancy among Ste20-like kinases in D. discoideum.
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Affiliation(s)
- Rajesh Arasada
- Adolf-Butenandt-Institut/Zellbiologie, Ludwig-Maximilians-Universität, Schillerstr. 42, D-80336 München, Germany
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6
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Farbrother P, Wagner C, Na J, Tunggal B, Morio T, Urushihara H, Tanaka Y, Schleicher M, Steinert M, Eichinger L. Dictyostelium transcriptional host cell response upon infection with Legionella. Cell Microbiol 2006; 8:438-56. [PMID: 16469056 DOI: 10.1111/j.1462-5822.2005.00633.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Differential gene expression of Dictyostelium discoideum after infection with Legionella pneumophila was investigated using DNA microarrays. Investigation of a 48 h time course of infection revealed several clusters of co-regulated genes, an enrichment of preferentially up- or downregulated genes in distinct functional categories and also showed that most of the transcriptional changes occurred 24 h after infection. A detailed analysis of the 24 h time point post infection was performed in comparison to three controls, uninfected cells and co-incubation with Legionella hackeliae and L. pneumophilaDeltadotA. One hundred and thirty-one differentially expressed D. discoideum genes were identified as common to all three experiments and are thought to be involved in the pathogenic response. Functional annotation of the differentially regulated genes revealed that apart from triggering a stress response Legionella apparently not only interferes with intracellular vesicle fusion and destination but also profoundly influences and exploits the metabolism of its host. For some of the identified genes, e.g. rtoA involvement in the host response has been demonstrated in a recent study, for others such a role appears plausible. The results provide the basis for a better understanding of the complex host-pathogen interactions and for further studies on the Dictyostelium response to Legionella infection.
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Affiliation(s)
- Patrick Farbrother
- Institut für Biochemie I, Medizinische Fakultät, Universität zu Köln, Joseph-Stelzmann-Str. 52, D-50931 Cologne, Germany
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7
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Kotsifas M, Barth C, de Lozanne A, Lay ST, Fisher PR. Chaperonin 60 and mitochondrial disease in Dictyostelium. J Muscle Res Cell Motil 2003; 23:839-52. [PMID: 12952082 DOI: 10.1023/a:1024444215766] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The single Dictyostelium chaperonin 60 gene, hspA, was cloned, sequenced and characterized. Sequence comparisons and a three-dimensional model for the structure of the encoded protein showed that it exhibits the conserved sequence and structural features expected for its role as the Dictyostelium mitochondrial chaperonin 60. Dictyostelium hspA contains two introns and, unusually for a member of this major heat shock gene family, is not stress-inducible in response to heat, cold or cadmium ions. Although transcription of hspA is down regulated during early Dictyostelium development in response to starvation, the levels of the chaperonin 60 protein remain constant throughout the life cycle. Consistent with the essential role of chaperonin 60 in mitochondrial biogenesis, we were unable to isolate mutants in which the hspA gene had been disrupted. However, transformants were isolated that exhibited differing levels of antisense inhibition of chaperonin 60 expression, depending upon the number of copies of the antisense-expressing plasmid in the genome. Orientation in phototaxis (and thermotaxis) was severely impaired in all antisense transformants, while growth and morphogenesis were markedly defective only in transformants with higher levels of antisense inhibition. This pattern of phenotypes is similar to that reported previously to result from targeted disruption of the mitochondrial large subunit rRNA gene in a subpopulation of mitochondria. This suggests that, regardless of the nature of the underlying genetic defect, mitochondrial deficiency impairs signal transduction more sensitively than other cellular activities.
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Affiliation(s)
- Martha Kotsifas
- Department of Microbiology, La Trobe University, Victoria 3086, Australia
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8
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9
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Westphal M, Müller-Taubenberger A, Noegel A, Gerisch G. Transcript regulation and carboxyterminal extension of ubiquitin inDictyostelium discoideum. FEBS Lett 2001. [DOI: 10.1016/0014-5793(86)81090-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Janssen KP, Rost R, Eichinger L, Schleicher M. Characterization of CD36/LIMPII homologues in Dictyostelium discoideum. J Biol Chem 2001; 276:38899-910. [PMID: 11489884 DOI: 10.1074/jbc.m103384200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The CD36/LIMPII family is ubiquitously expressed in higher eukaryotes and consists of integral membrane proteins that have in part been characterized as cell adhesion receptors, scavenger receptors, or fatty acid transporters. However, no physiological role has been defined so far for the members of this family that localize specifically to vesicular compartments rather than to the cell surface, namely lysosomal integral membrane protein type II (LIMPII) from mammals and LmpA from the amoeba Dictyostelium discoideum. LmpA, the first described CD36/LIMPII homologue from lower eukaryotes, has initially been identified as a suppressor of the profilin-minus phenotype. We report the discovery and initial characterization of two new CD36/LIMPII-related proteins, both of which share several features with LmpA: (i) their size is considerably larger than that of the CD36/LIMPII proteins from higher eukaryotes; (ii) they show the characteristic "hairpin" topology of this protein family; (iii) they are heavily N-glycosylated; and (iv) they localize to vesicular structures of putative endolysosomal origin. However, they show intriguing differences in their developmental regulation and exhibit different sorting signals of the di-leucine or tyrosine-type in their carboxyl-terminal tail domains. These features make them promising candidates as a paradigm for the study of the function and evolution of the as yet poorly understood CD36/LIMPII proteins.
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MESH Headings
- Amino Acid Sequence
- Amino Acids/chemistry
- Animals
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Blotting, Western
- CD36 Antigens/chemistry
- CD36 Antigens/genetics
- Cloning, Molecular
- Dictyostelium/chemistry
- Gene Expression Regulation, Developmental
- Glycosylation
- Leucine/chemistry
- Microscopy, Fluorescence
- Molecular Sequence Data
- Phenotype
- Phylogeny
- Protein Binding
- Protein Structure, Tertiary
- Protozoan Proteins
- Receptors, Immunologic
- Receptors, Lipoprotein/chemistry
- Receptors, Lipoprotein/genetics
- Receptors, Scavenger
- Subcellular Fractions
- Time Factors
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Affiliation(s)
- K P Janssen
- Institut für Zellbiologie, Ludwig-Maximilians-Universität, 80336 München, Germany.
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11
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Affiliation(s)
- J E Hughes
- Department of Biology, Utah State University, Logan 84322-5305, USA
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12
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Becker M, Matzner M, Gerisch G. Drainin required for membrane fusion of the contractile vacuole in Dictyostelium is the prototype of a protein family also represented in man. EMBO J 1999; 18:3305-16. [PMID: 10369671 PMCID: PMC1171411 DOI: 10.1093/emboj/18.12.3305] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The contractile vacuole expels water by forming a channel with the plasma membrane and thus enables cells to survive in a hypo-osmotic environment. Here we characterize drainin, a Dictyostelium protein involved in this process, as the first member of a protein family represented in fission yeast, Caenorhabditis elegans and man. Gene replacement in Dictyostelium shows that drainin acts at a checkpoint of channel formation between the contractile vacuole and the plasma membrane. A green fluorescent protein fusion of drainin localizes specifically to the contractile vacuole and rescues its periodic discharge in drainin-null cells. Drainin is a peripheral membrane protein, requiring a short hydrophobic stretch in its C-terminal region for localization and function. We suggest that drainin acts in a signaling cascade that couples a volume-sensing device in the vacuolar membrane to the membrane fusion machinery.
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Affiliation(s)
- M Becker
- Max-Planck-Institut für Biochemie, D-82152 Martinsried, Germany
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13
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Shammat IM, Welker DL. Mechanism of action of the Rep protein from the Dictyostelium Ddp2 plasmid family. Plasmid 1999; 41:248-59. [PMID: 10366530 DOI: 10.1006/plas.1999.1399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The two-hybrid system was used to show that the Rep proteins from three members of the Dictyostelium discoideum Ddp2 plasmid family, Ddp2, Ddp5, and Ddp6, form homomultimers but not heteromultimers when expressed in yeast cells. The results with deletion mutations suggest that multiple regions of the Rep proteins are involved in the multimerization. Electrophoretic mobility shift assays with heterologously expressed and purified Ddp2 Rep protein showed that it is a DNA binding protein. The nucleosomal organization of Ddp2 and Ddp6 in their inverted repeat and promoter regions was investigated. Analysis of mutants derived from the Ddp6 plasmid revealed that its Rep protein is required for nucleosome positioning (i.e., phasing) to occur in the promoter region. On the other hand, nucleosome positioning in the inverted repeat regions of both plasmids is not dependent on Rep protein but on either a feature of the DNA sequence or the binding of cellular factors, perhaps the Dictyostelium origin recognition complex. Rep protein is likely involved in transcription regulation and control of DNA replication, specifically amplification of plasmid at low copy numbers. The formation of homomultimers may be required for their regulatory activity.
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Affiliation(s)
- I M Shammat
- Department of Physiology, Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75235-9040, USA.
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14
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Karakesisoglou I, Janssen KP, Eichinger L, Noegel AA, Schleicher M. Identification of a suppressor of the Dictyostelium profilin-minus phenotype as a CD36/LIMP-II homologue. J Biophys Biochem Cytol 1999; 145:167-81. [PMID: 10189376 PMCID: PMC2148220 DOI: 10.1083/jcb.145.1.167] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Profilin is an ubiquitous G-actin binding protein in eukaryotic cells. Lack of both profilin isoforms in Dictyostelium discoideum resulted in impaired cytokinesis and an arrest in development. A restriction enzyme-mediated integration approach was applied to profilin-minus cells to identify suppressor mutants for the developmental phenotype. A mutant with wild-type-like development and restored cytokinesis was isolated. The gene affected was found to code for an integral membrane glycoprotein of a predicted size of 88 kD containing two transmembrane domains, one at the NH2 terminus and the other at the COOH terminus. It is homologous to mammalian CD36/LIMP-II and represents the first member of this family in D. discoideum, therefore the name DdLIMP is proposed. Targeted disruption of the lmpA gene in the profilin-minus background also rescued the mutant phenotype. Immunofluorescence revealed a localization in vesicles and ringlike structures on the cell surface. Partially purified DdLIMP bound specifically to PIP2 in sedimentation and gel filtration assays. A direct interaction between DdLIMP and profilin could not be detected, and it is unclear how far upstream in a regulatory cascade DdLIMP might be positioned. However, the PIP2 binding of DdLIMP points towards a function via the phosphatidylinositol pathway, a major regulator of profilin.
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Affiliation(s)
- I Karakesisoglou
- A.-Butenandt-Institut für Zellbiologie, Ludwig-Maximilians-Universität, 80336 München, Germany
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15
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Eichinger L, Bähler M, Dietz M, Eckerskorn C, Schleicher M. Characterization and cloning of a Dictyostelium Ste20-like protein kinase that phosphorylates the actin-binding protein severin. J Biol Chem 1998; 273:12952-9. [PMID: 9582328 DOI: 10.1074/jbc.273.21.12952] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
After receiving an external stimulus Dictyostelium amoebae are able to rearrange their actin cytoskeleton within seconds, and phosphorylation is a prime candidate for quick modification of cytoskeletal components. We isolated a kinase from cytosolic extracts that specifically phosphorylated severin, a Ca2+-dependent F-actin fragmenting protein. In gel filtration chromatography severin kinase eluted with a molecular mass of about 300 kDa and contained a 62-kDa component whose autophosphorylation caused a mobility shift in SDS-polyacrylamide gel electrophoresis and stimulated phosphorylation of severin. Severin kinase activity could be specifically precipitated with antibodies raised against the 62-kDa polypeptide. Phosphorylation of severin was strongly reduced in the presence of Ca2+, indicating additional regulation at the substrate level. Peptide sequencing and cloning of the cDNA demonstrated that the 62-kDa protein belongs to the Ste20p- or p21-activated protein kinase family. It is most closely related to the germinal center kinase subfamily with its N-terminal positioned catalytic domain followed by a presumptive regulatory domain at the C terminus. The presence of a Ste20-like severin kinase in Dictyostelium suggests a direct signal transduction from the plasma membrane to the cytoskeleton by phosphorylation of actin-binding proteins.
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Affiliation(s)
- L Eichinger
- Adolf-Butenandt-Institut/Zellbiologie, Ludwig-Maximilians-Universität, Schillerstrasse 42, 80336 München, Germany
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16
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Rieben WK, Gonzales CM, Gonzales ST, Pilkington KJ, Kiyosawa H, Hughes JE, Welker DL. Dictyostelium discoideum nuclear plasmid Ddp5 is a chimera related to the Ddp1 and Ddp2 plasmid families. Genetics 1998; 148:1117-25. [PMID: 9539429 PMCID: PMC1460040 DOI: 10.1093/genetics/148.3.1117] [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: 02/07/2023] Open
Abstract
The 14,955-bp Dictyostelium discoideum nuclear plasmid Ddp5 contains six transcribed open reading frames. One of these is related to the rep gene of the Ddp2 plasmid, and the other five are related to genes present on the Ddp1 plasmid. The absence of a homolog of the Ddp1 G1 gene, coupled with the presence of the Ddp2 rep gene homolog and of a 1.6-kb inverted repeat analogous to the inverted repeats on members of the Ddp2 plasmid family, suggests that Ddp5 uses Ddp2-like replication and copy number control mechanisms and that it should be assigned to the Ddp2 plasmid family. Ddp5 carries genes homologous to the D1/D3 and D2 genes of the Ddp1 plasmid as well as the Ddp1 G2/G3/D4, G5/D6, and G6/G4/D5 genes. The products of the Ddp5 G2-like, G5-like, and G6-like genes are likely to be transcription factors regulating the expression of themselves and of the other Ddp5 genes. The D1-like and D2-like genes may confer a selective advantage to plasmid-bearing cells, because they can be deleted from plasmid-based shuttle vectors with no apparent effect on vector maintenance. Updated sequence information for the Ddp1 G5/D6, D1/D3, and D2 genes as well as the Dmp1 and Dmp2 G5-like genes is presented. The locations of introns in the G5-like and D1-like genes of Ddp5 and in the homologous genes of the Ddp1, Dmp1, and Dmp2 plasmids were identified. These introns all have GU at the 5' intron border and AG at the 3' intron border, are short (59 to 71 nucleotides), and are AT-rich. A conserved HHCC domain was identified in the G5 proteins; this is a putative zinc binding domain and may be involved in protein-DNA interaction.
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Affiliation(s)
- W K Rieben
- Biology Department, Utah State University, Logan 84322-5305, USA
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17
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Shimada T, Sasaki N, Ohkura R, Sutoh K. Alanine scanning mutagenesis of the switch I region in the ATPase site of Dictyostelium discoideum myosin II. Biochemistry 1997; 36:14037-43. [PMID: 9369475 DOI: 10.1021/bi971837i] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In order to determine the functional roles of the conserved sequence (NXNSSRFG) of the "switch I" loop (residues 233-240 in Dictyostelium myosin II), alanine scanning mutagenesis was performed on Dictyostelium myosin II. N233A and S237A mutant myosins did not bind a fluorescent analog of ADP, mant-deoxyADP, at the low concentration range (micromolar and had low level of ATPase activities. They were nonmotile when examined by the in vitro motility assay. Dictyostelium cells expressing these myosins showed worse phenotypes than that of myosin-null cells. In contrast to these mutant myosins, R238A myosin tightly bound mant-deoxyADP. However, the mutant had a defect in the ATP hydrolysis step and exhibited the lowest ATPase activities among the mutants examined here. The R238A myosin was nonmotile. R238C or R238H mutations, which mimic the Usher syndrome mutations, generated myosins with similar functional defects to those of the R238A mutation. Cells expressing the R238A myosin exhibited the phenotype similar to that of the myosin-null cells. N235A, S236A, F239A, and G240A myosins retained moderate levels of ATPase activities and could drive sliding of actin filaments at various speeds. Phenotypes of cells expressing them were very similar to that of the wild-type cells. Taken together, these results suggest that side chains of N233 and S237 may play essential roles in holding a nucleotide in the ATPase pocket and that R238 may play crucial roles in the ATP hydrolysis step, while those of the other residues in the switch I loop are not essential for the process.
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Affiliation(s)
- T Shimada
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Tokyo 153, Japan
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18
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Matthews GD, Goodwin TJ, Butler MI, Berryman TA, Poulter RT. pCal, a highly unusual Ty1/copia retrotransposon from the pathogenic yeast Candida albicans. J Bacteriol 1997; 179:7118-28. [PMID: 9371461 PMCID: PMC179655 DOI: 10.1128/jb.179.22.7118-7128.1997] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Retrotransposons are mobile genetic elements. They can transpose via the reverse transcription of mRNA into double-stranded DNA (dsDNA) followed by the insertion of this dsDNA into new sites within the host genome. The unintegrated, linear, dsDNA form of retrotransposons is usually very rare. We report here the isolation of a retrotransposon from Candida albicans which is unusual in this respect. This element, which we have named pCal, was first identified as a distinct band when uncut C. albicans DNA was examined on an agarose gel. Sequence analysis of the cloned element revealed that it is a retrotransposon belonging to the Ty1/copia group. It is estimated that pCal produces 50 to 100 free, linear, dsDNA copies of itself per cell. This is a much higher level of expression than even that of the system in which Ty1 is expressed behind the highly active GAL1 promoter on a high-copy-number plasmid (about 10 copies per cell). Another unusual feature of pCal is that its Pol enzymes are likely to be expressed via the pseudoknot-assisted suppression of an upstream, in-phase stop codon, as has been shown for Moloney murine leukemia virus.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Candida albicans/genetics
- Chromosome Mapping
- Cloning, Molecular
- Codon, Terminator
- DNA Transposable Elements/genetics
- DNA, Fungal/analysis
- DNA, Fungal/genetics
- DNA, Fungal/isolation & purification
- Endopeptidases/genetics
- Gene Expression Regulation, Fungal
- Gene Products, pol/genetics
- Gene Products, pol/metabolism
- Integrases/genetics
- Molecular Sequence Data
- Molecular Structure
- Open Reading Frames
- Phylogeny
- Plasmids
- Promoter Regions, Genetic
- RNA-Directed DNA Polymerase/genetics
- Retroelements
- Ribonucleases/genetics
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
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Affiliation(s)
- G D Matthews
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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Niewöhner J, Weber I, Maniak M, Müller-Taubenberger A, Gerisch G. Talin-null cells of Dictyostelium are strongly defective in adhesion to particle and substrate surfaces and slightly impaired in cytokinesis. J Biophys Biochem Cytol 1997; 138:349-61. [PMID: 9230077 PMCID: PMC2138202 DOI: 10.1083/jcb.138.2.349] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Dictyostelium discoideum contains a full-length homologue of talin, a protein implicated in linkage of the actin system to sites of cell-to-substrate adhesion in fibroblasts and neuronal growth cones. Gene replacement eliminated the talin homologue in Dictyostelium and led to defects in phagocytosis and cell-to-substrate interaction of moving cells, two processes dependent on a continuous cross talk between the cell surface and underlying cytoskeleton. The uptake rate of yeast particles was reduced, and only bacteria devoid of the carbohydrate moiety of cell surface lipopolysaccharides were adhesive enough to be recruited by talin-null cells in suspension and phagocytosed. Cell-to-cell adhesion of undeveloped cells was strongly impaired in the absence of talin, in contrast with the cohesion of aggregating cells mediated by the phospholipid-anchored contact site A glycoprotein, which proved to be less talin dependent. The mutant cells were still capable of moving and responding to a chemoattractant, although they attached only loosely to a substrate via small areas of their surface. With their high proportion of binucleated cells, the talin-null mutants revealed interactions of the mitotic apparatus with the cell cortex that were not obvious in mononucleated cells.
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Affiliation(s)
- J Niewöhner
- Max-Planck-Institut für Biochemie, D-82152 Martinsried, Germany
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20
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Stoeckelhuber M, Noegel AA, Eckerskorn C, Köhler J, Rieger D, Schleicher M. Structure/function studies on the pH-dependent actin-binding protein hisactophilin in Dictyostelium mutants. J Cell Sci 1996; 109 ( Pt 7):1825-35. [PMID: 8832405 DOI: 10.1242/jcs.109.7.1825] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our previous studies have shown that the actin-binding protein hisactophilin from Dictyostelium discoideum is a candidate for organizing the actin cytoskeleton at the plasma membrane in a pH-dependent manner. To further characterize this interaction we isolated hisactophilin overexpression (hisII+) and hisactophilin minus (his-) mutants. D. discoideum contains two hisactophilin isoforms; both genes are independently transcribed and carry a short intron at the same position of the coding region. The deduced amino acid sequence of hisactophilin II showed a characteristic high content of 35 histidine residues out of a total 118 amino acids. After transformation of Dictyostelium AX2 wild-type cells with a genomic fragment designed to inactivate the hisactophilin I gene we obtained hisactophilin II overexpressing mutants (hisII+). Multiple integration of the vector led to strong overexpression of hisactophilin II which even outnumbered the actin concentration by a factor of two. Hisactophilin II protein showed the same biochemical properties as hisactophilin I during purification and in its pH-dependent binding to F-actin; as shown by mass spectrometry the hisactophilin II fraction was almost completely myristoylated despite of this high overexpression. The inactivation of both hisactophilin genes was achieved by gene replacement with a vector construct encompassing parts of gene I and gene II connected by a geneticin cassette. The properties of the hisII+ and his- cells with regard to growth in shaking culture and on Klebsiella plates, development, chemotaxis and morphology were not affected under normal conditions. However, the hisII+ transformants revealed a significant difference to wild-type cells and his- cells when the cytoplasmic pH was lowered by diethylstilbestrol (DES), a proton pump inhibitor. HisII+ cells were more resistant to the acidification; in contrast to AX2 wild-type cells and his- cells they did not form plasma membrane protrusions, showed an increase in F-actin content, and contained large clusters of F-actin. Lowering the internal pH caused an accumulation of hisactophilin below the plasma membrane. The fact that cells deficient in hisactophilin again lose resistance to acidification is in good agreement with the hypothesis that hisactophilin functions as a pH sensor at the plasma membrane by reversibly connecting the membrane with the actin cortical network upon local changes of the proton concentration.
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Affiliation(s)
- M Stoeckelhuber
- Adolf-Butenandt-Institut/Zellbiologie, Ludwig-Maximilians-Universität, München, Germany
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21
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André B, Noegel AA, Schleicher M. Dictyostelium discoideum contains a family of calmodulin-related EF-hand proteins that are developmentally regulated. FEBS Lett 1996; 382:198-202. [PMID: 8612752 DOI: 10.1016/0014-5793(96)00176-7] [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: 01/31/2023]
Abstract
A full-length genomic DNA fragment that codes for a novel EF-hand protein Dictyostelium discoideum was cloned and sequenced. The protein is composed of 168 amino acids and contains four consensus sequences that are typical for (Ca2+)-binding EF-hand domains. The protein sequence exhibits only minor similarities to other calmodulin-type proteins from Dictyostelium. The genomic DNA harbors two short introns; their positions suggest that the gene is unrelated to the EF-hand proteins from the calmodulin group. Northern blot analysis showed that the mRNA level was significantly increased during development. Polyclonal antibodies raised against the recombinant protein recognized in Western blots a protein of about 20 kDa. Like the mRNA, also the protein was more abundant in developing cells. Overlay experiments with 45Ca2+ indicated that the EF-hands in fact have (Ca2+)-binding activity. The recent description of CBP1, another calmodulin-type Dictyostelium protein that is upregulated during development [Coukell et al. (1995) FEBS Lett. 362, 342-346], suggests that D. discoideum contains a family of EF-hand proteins that have specific functions during distinct steps of development. We therefore designate the protein described in this report as CBP2.
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Affiliation(s)
- B André
- Adolf-Butenandt-Institut/Zellbiologie, München, Germany
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22
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Williams KL, Emslie KR, Slade MB. Recombinant glycoprotein production in the slime mould Dictyostelium discoideum. Curr Opin Biotechnol 1995; 6:538-42. [PMID: 7579665 DOI: 10.1016/0958-1669(95)80089-1] [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: 01/26/2023]
Abstract
Dictyostelium discoideum is a well known amoeboid organism, with unicellular and multicellular life-cycle stages, that is used for studying cell and developmental biology. With advances in gene-disruption technology and transformation of this organism, many homologous proteins have been expressed either to complement defective proteins or to study basic cell biology. Now, D. discoideum is being used to express heterologous proteins that are difficult to study in other systems, and its unique cell biology is being exploited to facilitate a wide range of protein modifications. In the past year, substantial progress has been made in expressing correctly folded forms of malarial circumsporozoite antigen and rotavirus surface glycoprotein VP7. Exciting developments have also been made in expressing human muscarinic receptors.
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23
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Yin Y, Williamson BD, Rutherford CL. An autonomously propagating luciferase-encoding vector for Dictyostelium discoideum. Gene 1994; 150:293-8. [PMID: 7821794 DOI: 10.1016/0378-1119(94)90440-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have constructed a luc reporter vector for Dictyostelium discoideum using a 626-bp fragment from the nuclear-associated plasmid Ddp2. The ori from Ddp2 is localized within this fragment and was used to provide an autonomous replication sequence for the reporter vector. This reporter vector was stably retained in D. discoideum AX3K cells without alteration. The vector molecule was also found to exist in relatively low copy number compared to other Dictyostelium vectors in the transformed cells. We demonstrated the utility of this vector as a reporter vector with glycogen synthase promoter/luc fusions of varying sizes.
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Affiliation(s)
- Y Yin
- Department of Biology, Molecular and Cellular Biology Program, Virginia Tech, Blacksburg 24061
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24
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Plasmid maintenance functions encoded on Dictyostelium discoideum nuclear plasmid Ddp1. Mol Cell Biol 1994. [PMID: 8065344 DOI: 10.1128/mcb.14.9.6117] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
All of the plasmid-carried genes expressed during vegetative growth are essential for long-term maintenance of plasmid Ddp1 in the nucleus of Dictyostelium discoideum. Deletion of Ddp1 genes expressed only during development had no detectable effect on plasmid maintenance. Deletion of vegetatively expressed genes, either singly or in pairs, resulted in (i) a rapid loss of plasmid from cells grown in the absence of selection for plasmid retention, (ii) variation in the proportion of monomer to multimer forms of the plasmid molecules, and/or (iii) abnormalities in plasmid copy number. At least two plasmid-encoded gene products influence patterns of expression of plasmid genes.
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25
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Hughes JE, Kiyosawa H, Welker DL. Plasmid maintenance functions encoded on Dictyostelium discoideum nuclear plasmid Ddp1. Mol Cell Biol 1994; 14:6117-24. [PMID: 8065344 PMCID: PMC359138 DOI: 10.1128/mcb.14.9.6117-6124.1994] [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: 01/28/2023] Open
Abstract
All of the plasmid-carried genes expressed during vegetative growth are essential for long-term maintenance of plasmid Ddp1 in the nucleus of Dictyostelium discoideum. Deletion of Ddp1 genes expressed only during development had no detectable effect on plasmid maintenance. Deletion of vegetatively expressed genes, either singly or in pairs, resulted in (i) a rapid loss of plasmid from cells grown in the absence of selection for plasmid retention, (ii) variation in the proportion of monomer to multimer forms of the plasmid molecules, and/or (iii) abnormalities in plasmid copy number. At least two plasmid-encoded gene products influence patterns of expression of plasmid genes.
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Affiliation(s)
- J E Hughes
- Department of Biology, Utah State University, Logan 84322-5500
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26
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Hughes JE, Podgorski GJ, Welker DL. Selection of Dictyostelium discoideum transformants and analysis of vector maintenance using live bacteria resistant to G418. Plasmid 1992; 28:46-60. [PMID: 1518912 DOI: 10.1016/0147-619x(92)90035-9] [Citation(s) in RCA: 26] [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
A protocol that allows the rapid isolation and growth of large numbers of independent G418-resistant Dictyostelium discoideum transformant colonies on the surface of agar media with live bacteria was developed. Transformants grown under these conditions form normal fruiting bodies. Discovery that aggregation of nontransformants was inhibited at a nonselective level of G418 (25 to 35 micrograms/ml) led to the development of a vector maintenance assay. Using this assay we examined the stability of recombinant plasmids derived from the D. discoideum native plasmids Ddp1 and Ddp2. We conclude that the origin of replication of plasmid Ddp1 does not alone confer stable maintenance and thus, Ddp1 must bear additional sequences required for its own maintenance. Analysis of the maintenance of vectors derived from Ddp2 showed that autonomously replicating shuttle vectors that contained bacterial plasmid DNA and from which one element of the Ddp2 inverted repeat was removed were much less stable than vectors that contained a complete inverted repeat or that did not carry a bacterial plasmid. Sequences between the 3' end of the rep gene and the inverted repeat appear to play a role in plasmid maintenance. An intact rep gene and one copy of the inverted repeat element were required for extrachromosomal replication. Maintenance of extrachromosomal vectors was found to be strain dependent. Four traits distinguishing integrating vectors from those capable of autonomous replication were identified.
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Affiliation(s)
- J E Hughes
- Biology Department, Utah State University, Logan 84322-5500
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27
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Abstract
Dgp1, a circular 4.4-kb plasmid found in the nuclei of Dictyostelium giganteum strain DG61, is a member of the same plasmid family as plasmids Ddp2 and pDG1. Dgp1 has sequence similarity to a conserved region of the Ddp2 and pDG1 open reading frames. As with Ddp2 and pDG1, a single large RNA is transcribed from Dgp1. This 3.3-kb transcript is present at about 350 copies per vegetative cell. The transcript abundance decreased about 10-fold in early aggregation and continued at this lower level until late culmination when it returned to the level seen in vegetative cells. Dgp1 has a repeat of several hundred base pairs in a location, relative to the transcribed region, similar to the inverted repeats found in Ddp2 and pDG1. Dgp1 cannot be maintained as a plasmid in Dictyostelium discoideum AX4 cells, suggesting that Dgp1 carries species-specific maintenance elements.
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Affiliation(s)
- Y Yin
- Department of Biology, Utah State University, Logan 84322-5500
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28
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Powell JA, Galindo J, Firtel RA. A negative transcriptional control region of a developmentally-regulated gene co-localizes with the origin of replication of an endogenous plasmid in Dictyostelium. Nucleic Acids Res 1992; 20:2795-802. [PMID: 1319575 PMCID: PMC336924 DOI: 10.1093/nar/20.11.2795] [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: 12/26/2022] Open
Abstract
The endogenous nuclear plasmid Ddp1 from the wild-type Dictyostelium discoideum strain NC4 has been cloned, its origin of replication has been localized, and plasmid-encoded genes have been mapped that are preferentially expressed during growth or development. Here we present an analysis of the regulation of the Ddp1-encoded gene d5, which, in wild-type cells, is expressed only during the multicellular stages of development. In this study, we show that sequences 3' to the d5 coding region are required to suppress constitutive expression of d5 from aberrant transcriptional start sites and that this regulatory region acts at a distance and in an orientation-independent manner. The cis-acting negative regulatory element(s) necessary for repression of aberrant d5 expression is either very tightly linked or identical to sequences required for extrachromosomal replication, such that all 3' deletions that cause constitutive d5 expression result in the integration of the plasmid into the D. discoideum genome. Placing d5 (without the 3' regions containing the Ddp1 origin) on an extrachromosomal vector based on another endogenous plasmid (Ddp2) did not restore proper transcriptional regulation, suggesting that an extrachromosomal environment alone is not sufficient to confer proper transcriptional regulation to d5.
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Affiliation(s)
- J A Powell
- Department of Biology, University of California, San Diego, La Jolla 92093-0634
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29
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Chang AC, Hall RM, Williams KL. Bleomycin resistance as a selectable marker for transformation of the eukaryote, Dictyostelium discoideum. Gene X 1991; 107:165-70. [PMID: 1720754 DOI: 10.1016/0378-1119(91)90312-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
An expression cassette was constructed, which has the bacterial bleomycin (Bm) resistance-encoding gene (ble) fused to the Dictyostelium discoideum actin-6 promoter, with a segment of 3'-flanking DNA from the actin-8-encoding gene placed downstream from the ble gene to serve as a transcription terminator. Plasmid pMUW161, which contains this cassette and the D. discoideum plasmid Ddp2 origin of DNA replication, transformed D. discoideum with high efficiency under Bm selection. Hence, this construct is useful as a dominant selectable marker for D. discoideum.
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Affiliation(s)
- A C Chang
- School of Biological Sciences, Macquarie University, Sydney, N.S.W., Australia
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30
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Purification and cDNA-derived sequence of adenylosuccinate synthetase from Dictyostelium discoideum. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52269-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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31
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Fechheimer M, Murdock D, Carney M, Glover CV. Isolation and sequencing of cDNA clones encoding the Dictyostelium discoideum 30,000-dalton actin-bundling protein. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)49930-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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32
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Egelhoff TT, Titus MA, Manstein DJ, Ruppel KM, Spudich JA. Molecular genetic tools for study of the cytoskeleton in Dictyostelium. Methods Enzymol 1991; 196:319-34. [PMID: 2034127 DOI: 10.1016/0076-6879(91)96029-q] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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33
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Slade MB, Chang AC, Williams KL. The sequence and organization of Ddp2, a high-copy-number nuclear plasmid of Dictyostelium discoideum. Plasmid 1990; 24:195-207. [PMID: 2077544 DOI: 10.1016/0147-619x(90)90003-u] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The complete nucleotide sequence of the plasmid Ddp2 found in the nucleus of the simple eukaryote Dictyostelium discoideum is reported. This 5852-bp plasmid contains a 2661-bp open reading frame (ORF), named the "Rep gene," and 501-bp imperfect inverted repeats. A 1762-bp section of Ddp2, which includes one of the 501-bp repeat sequences, could be deleted without abolishing extrachromosomal replication. Deletion of the second 501-bp repeat, or interruption of the Rep gene, removed the ability to replicate extrachromosomally. We suggest that Ddp2 encodes a protein, "REP," that positively regulates replication initiation, a regulatory mechanism different from that of the yeast 2 mu plasmid which also possesses inverted repeat sequences. Ddp2 has a structure similar to that of plasmid pDG1, found in an unidentified isolate of Dictyostelium, with a similar sized ORF and inverted repeats. A common evolutionary origin is suggested by considerable sequence homology between the ORFs of pDG1 and Ddp2.
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Affiliation(s)
- M B Slade
- School of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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34
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Chang AC, Slade MB, Williams KL. Identification of the origin of replication of the eukaryote Dictyostelium discoideum nuclear plasmid Ddp2. Plasmid 1990; 24:208-17. [PMID: 2077545 DOI: 10.1016/0147-619x(90)90004-v] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ddp2 is a 5.8-kb, high-copy-number, nuclear plasmid found in the eukaryote Dictyostelium discoideum. We have identified two functional domains, a large open reading frame (Rep gene) and a 626-bp fragment containing an origin of replication (ori). The ori, when cloned into a shuttle vector, confers stable extrachromosomal replication in D. discoideum, provided that the Rep gene, which acts in trans, is integrated into the host genome. Ddp2 carries a 501-bp imperfect inverted repeat, and part of the ori overlaps with one of these repeats. The ori sequence contains two direct repeats of 49 bp comprising two 10-bp "TGTCATGACA" palindromes separated by a poly(T.A) sequence. Deletion of either 49-bp repeat abolished extrachromosomal replication.
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Affiliation(s)
- A C Chang
- School of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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35
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Brink M, Gerisch G, Isenberg G, Noegel AA, Segall JE, Wallraff E, Schleicher M. A Dictyostelium mutant lacking an F-actin cross-linking protein, the 120-kD gelation factor. J Cell Biol 1990; 111:1477-89. [PMID: 1698791 PMCID: PMC2116242 DOI: 10.1083/jcb.111.4.1477] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Actin-binding proteins are known to regulate in vitro the assembly of actin into supramolecular structures, but evidence for their activities in living nonmuscle cells is scarce. Amebae of Dictyostelium discoideum are nonmuscle cells in which mutants defective in several actin-binding proteins have been described. Here we characterize a mutant deficient in the 120-kD gelation factor, one of the most abundant F-actin cross-linking proteins of D. discoideum cells. No F-actin cross-linking activity attributable to the 120-kD protein was detected in mutant cell extracts, and antibodies recognizing different epitopes on the polypeptide showed the entire protein was lacking. Under the conditions used, elimination of the gelation factor did not substantially alter growth, shape, motility, or chemotactic orientation of the cells towards a cAMP source. Aggregates of the mutant developed into fruiting bodies consisting of normally differentiated spores and stalk cells. In cytoskeleton preparations a dense network of actin filaments as typical of the cell cortex, and bundles as they extend along the axis of filopods, were recognized. A significant alteration found was an enhanced accumulation of actin in cytoskeletons of the mutant when cells were stimulated with cyclic AMP. Our results indicate that control of cell shape and motility does not require the fine-tuned interactions of all proteins that have been identified as actin-binding proteins by in vitro assays.
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Affiliation(s)
- M Brink
- Max-Planck-Institut für Biochemie, Martinsried, Federal Republic of Germany
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36
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The extrachromosomal replication of Dictyostelium plasmid Ddp2 requires a cis-acting element and a plasmid-encoded trans-acting factor. Mol Cell Biol 1990. [PMID: 2192261 DOI: 10.1128/mcb.10.7.3727] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dictyostelium discoideum plasmid Ddp2 from the wild strain WS380B is a 5.8-kilobase (kb) supercoiled circle with a copy number of 300 per haploid genome. We previously described the construction of an extrachromosomally replicating transformation vector pnDeI carrying 4.7 kb of Ddp2 sequences (B. Leiting, and A. Noegel, Plasmid 20:241-248, 1988). In order to reduce the sequences required for extrachromosomal maintenance in D. discoideum, we characterized Ddp2 by sequence analysis, by deletion experiments, by transcription mapping, by electrophoretic mobility shift assays, and by expression of its single open reading frame in Escherichia coli. Two elements were involved in replication of Ddp2: a cis-acting sequence located on a 592-base-pair (bp) fragment that consisted of 220 bp of essential and 372 bp of auxiliary sequences, and a 2.7-kb open reading frame which most likely encodes a trans-acting factor. The cis- and trans-acting elements did not overlap and were shown to act independently from the location of the sequences encoding the trans-acting factor.
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37
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Leiting B, Lindner IJ, Noegel AA. The extrachromosomal replication of Dictyostelium plasmid Ddp2 requires a cis-acting element and a plasmid-encoded trans-acting factor. Mol Cell Biol 1990; 10:3727-36. [PMID: 2192261 PMCID: PMC360823 DOI: 10.1128/mcb.10.7.3727-3736.1990] [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: 12/30/2022] Open
Abstract
Dictyostelium discoideum plasmid Ddp2 from the wild strain WS380B is a 5.8-kilobase (kb) supercoiled circle with a copy number of 300 per haploid genome. We previously described the construction of an extrachromosomally replicating transformation vector pnDeI carrying 4.7 kb of Ddp2 sequences (B. Leiting, and A. Noegel, Plasmid 20:241-248, 1988). In order to reduce the sequences required for extrachromosomal maintenance in D. discoideum, we characterized Ddp2 by sequence analysis, by deletion experiments, by transcription mapping, by electrophoretic mobility shift assays, and by expression of its single open reading frame in Escherichia coli. Two elements were involved in replication of Ddp2: a cis-acting sequence located on a 592-base-pair (bp) fragment that consisted of 220 bp of essential and 372 bp of auxiliary sequences, and a 2.7-kb open reading frame which most likely encodes a trans-acting factor. The cis- and trans-acting elements did not overlap and were shown to act independently from the location of the sequences encoding the trans-acting factor.
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Affiliation(s)
- B Leiting
- Abteilung Zellbiologie, Max-Planck-Institut fuer Biochemie, Martinsried bei Muenchen, Federal Republic of Germany
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38
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Noegel AA, Gerisch G, Lottspeich F, Schleicher M. A protein with homology to the C-terminal repeat sequence of Octopus rhodopsin and synaptophysin is a member of a multigene family in Dictyostelium discoideum. FEBS Lett 1990; 266:118-22. [PMID: 2114316 DOI: 10.1016/0014-5793(90)81521-o] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Monoclonal antibodies were raised against a protein with a molecular mass of 24 kDa that has been described as a membrane-associated, actin binding protein from Dictyostelium discoideum [( 1985) J. Cell Biol. 100, 727-735]. Using these monoclonal antibodies we isolated from a lambda gt11 expression library cDNA clones coding for this protein. The cDNA deduced amino acid sequence revealed the presence of an unusual carboxy-terminus which has homologies to the C-termini of Octopus rhodopsin and synaptophysin. This part of the protein sequence contains 5 direct repeats with the motif GYP (P)Q(P). Southern and Northern blots showed that this sequence is present in a series of Dictyostelium genes transcribed in all stages of development.
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Affiliation(s)
- A A Noegel
- Max-Planck-Institut für Biochemie, Martinsried, FRG
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39
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Gurniak CB, Bang AG, Noegel AA. Transcript and sequence analysis of a 5.1 kb contiguous fragment of Dictyostelium discoideum plasmid Ddp1 that contains the origin of replication and codes for several transcripts. Curr Genet 1990; 17:321-5. [PMID: 2340592 DOI: 10.1007/bf00314879] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The sequence of a 5.1 kb contiguous fragment of the Dictyostelium plasmid Ddp1 is presented. This fragment contains three long open reading frames which correspond to the developmentally regulated and cAMP-inducible transcript d-5, the growth phase specific transcript g-1 and the three overlapping transcripts g-2, g-3 and d-4. The transcripts that originate from Ddp1 resemble chromosomally-encoded ones: they are products of RNA polymerase II, are polyadenylated and accumulate at different time points during Dictyostelium development. The presented nucleotide sequence encompasses a 2,033 bp HindIII fragment that had previously been shown to carry all the information necessary for extrachromosomal replication. None of the identified genes is completely contained within this HindIII fragment.
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Affiliation(s)
- C B Gurniak
- Max-Planck-Institut für Biochemie, Martinsried, Federal Republic of Germany
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Wiesmüller L, Noegel AA, Bârzu O, Gerisch G, Schleicher M. cDNA-derived sequence of UMP-CMP kinase from Dictyostelium discoideum and expression of the enzyme in Escherichia coli. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39331-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Hughes JE, Welker DL. Copy number control and compatibility of nuclear plasmids in Dictyostelium discoideum. Plasmid 1989; 22:215-23. [PMID: 2633208 DOI: 10.1016/0147-619x(89)90004-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Copy number of the endogenous nuclear plasmids of Dictyostelium discoideum is a plasmid-specific trait. Copy number is stable over time, is constant relative to ploidy level, is independent of host cell genetic background, and is independent of the presence of a second unrelated plasmid in the same nucleus. Unrelated plasmids are compatible with one another within a single nucleus. Pairwise combinations of Ddp1, Ddp2, and Ddp5 were stably maintained over many generations in the absence of selection. In contrast, one of the D. discoideum plasmids (Ddp2) was incompatible with a recombinant plasmid derived from it (p7d2). In the absence of selection for retention of p7d2, transformants contain either one or the other but not both plasmids. The plasmids are stably maintained in host cells with differing genetic backgrounds, although plasmid-free colonies were detected at a frequency of about 1-2% in populations of some strains after 50 generations growth following a previous cloning.
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Affiliation(s)
- J E Hughes
- Department of Biology, Utah State University, Logan 84322-5500
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Abstract
We have constructed an expression cartridge which has the bacterial hygromycin resistance gene (hph) fused to the Dictyostelium discoideum actin 15 promoter, with a segment of 3'-flanking DNA from the actin 15 locus placed downstream of the hph gene to serve as a transcription terminator. The plasmid pDE109, which contained this cartridge and a Dictyostelium origin of replication, transformed D. discoideum with high efficiency under hygromycin selection. The availability of this selectable marker circumvents the previous limitation of having G418 resistance as the only selectable marker for this organism; secondary transformation can now be used to introduce DNA into previously transformed cell lines.
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Noegel AA, Rapp S, Lottspeich F, Schleicher M, Stewart M. The Dictyostelium gelation factor shares a putative actin binding site with alpha-actinins and dystrophin and also has a rod domain containing six 100-residue motifs that appear to have a cross-beta conformation. J Cell Biol 1989; 109:607-18. [PMID: 2668299 PMCID: PMC2115711 DOI: 10.1083/jcb.109.2.607] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The 120-kD gelation factor and alpha-actinin are among the most abundant F-actin cross-linking proteins in Dictyostelium discoideum. Both molecules are homodimers and have extended rod-like configurations that are respectively approximately 35 and 40 nm long. Here we report the complete cDNA sequence of the 120-kD gelation factor which codes for a protein of 857 amino acids. Its calculated molecular mass is 92.2 kD which is considerably smaller than suggested by its mobility in SDS-PAGE. Analysis of the sequence shows a region that is highly homologous to D. discoideum alpha-actinin, chicken fibroblast alpha-actinin, and human dystrophin. This conserved domain probably represents an actin binding site that is connected to the rod-forming part of the molecule via a highly charged stretch of amino acids. Whereas the sequence of alpha-actinin (Noegel, A., W. Witke, and M. Schleicher. 1987. FEBS [Fed. Eur. Biochem. Soc.] Lett. 221:391-396) suggests that the extended rod domain of the molecule is based on four spectrin-like repeats with high alpha-helix potential, the rod domain of the 120-kD gelation factor is constructed from six 100-residue repeats that have a high content of glycine and proline residues and which, in contrast to alpha-actinin, do not appear to have a high alpha-helical content. These repeats show a distinctive pattern of regions that have high beta-sheet potential alternating with short zones rich in residues with a high potential for turns. This observation suggests that each 100-residue motif has a cross-beta conformation with approximately nine sheets arranged perpendicular to the long axis of the molecule. In the high beta-potential zones every second residue is often hydrophobic. In a cross-beta structure, this pattern would result in one side of the domain having a surface rich in hydrophobic side chains which could account for the dimerization of the 120-kD gelation factor subunits.
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Affiliation(s)
- A A Noegel
- Max-Planck-Institut, Martinsried, Federal Republic of Germany
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Egelhoff TT, Brown SS, Manstein DJ, Spudich JA. Hygromycin resistance as a selectable marker in Dictyostelium discoideum. Mol Cell Biol 1989; 9:1965-8. [PMID: 2546056 PMCID: PMC362988 DOI: 10.1128/mcb.9.5.1965-1968.1989] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have constructed an expression cartridge which has the bacterial hygromycin resistance gene (hph) fused to the Dictyostelium discoideum actin 15 promoter, with a segment of 3'-flanking DNA from the actin 15 locus placed downstream of the hph gene to serve as a transcription terminator. The plasmid pDE109, which contained this cartridge and a Dictyostelium origin of replication, transformed D. discoideum with high efficiency under hygromycin selection. The availability of this selectable marker circumvents the previous limitation of having G418 resistance as the only selectable marker for this organism; secondary transformation can now be used to introduce DNA into previously transformed cell lines.
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Affiliation(s)
- T T Egelhoff
- Department of Cell Biology, Stanford University School of Medicine, California 94305
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Sandholzer U, Centea-Intemann M, Noegel AA, Lottspeich F. cDNA and derived amino acid sequence of the hypusine containing protein from Dictyostelium discoideum. FEBS Lett 1989; 246:94-100. [PMID: 2540042 DOI: 10.1016/0014-5793(89)80260-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The eukaryotic translation initiation factor eIF-4D is the only protein known to contain the unusual amino acid hypusine, a posttranslationally modified lysine. For the production of monoclonal antibodies the hypusine-containing protein (HP) was isolated from Dictyostelium discoideum. Using these monoclonal antibodies, a full-length cDNA clone was isolated from a lambda gt11 library. The D. discoideum HP consists of 169 amino acids and has a molecular mass of 18.3 kDa. It is encoded by a single gene. Tryptic and cyanogen bromide peptides were prepared from the purified protein and sequenced. The hypusine residue is located at amino acid position 65 of the HP. The corresponding mRNA of approx. 0.6 kb is present throughout the life cycle of D. discoideum.
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André E, Brink M, Gerisch G, Isenberg G, Noegel A, Schleicher M, Segall JE, Wallraff E. A Dictyostelium mutant deficient in severin, an F-actin fragmenting protein, shows normal motility and chemotaxis. J Cell Biol 1989; 108:985-95. [PMID: 2537840 PMCID: PMC2115376 DOI: 10.1083/jcb.108.3.985] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A severin deficient mutant of Dictyostelium discoideum has been isolated by the use of colony immunoblotting after chemical mutagenesis. In homogenates of wild-type cells, severin is easily detected as a very active F-actin fragmenting protein. Tests for severin in the mutant, HG1132, included viscometry for the assay of F-actin fragmentation in fractions from DEAE-cellulose columns, labeling of blots with monoclonal and polyclonal antibodies, and immunofluorescent-labeling of cryosections. Severin could not be detected in the mutant using these methods. The mutation in HG1132 is recessive and has been mapped to linkage group VII. The mutant failed to produce the normal severin mRNA, but small amounts of a transcript that was approximately 100 bases larger than the wild-type mRNA were detected in the mutant throughout all stages of development. On the DNA level a new Mbo II restriction site was found in the mutant within the coding region of the severin gene. The severin deficient mutant cells grew at an approximately normal rate, aggregated and formed fruiting bodies with viable spores. By the use of an image processing system, speed of cell movement, turning rates, and precision of chemotactic orientation in a stable gradient of cyclic AMP were quantitated, and no significant differences between wild-type and mutant cells were found. Thus, under the culture conditions used, severin proved to be neither essential for growth of D. discoideum nor for any cell function that is important for aggregation or later development.
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Affiliation(s)
- E André
- Max-Planck-Institute für Biochemie und Psychiatrie, Martinsried bei München, Federal Republic of Germany
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Orii H, Tanaka Y, Yanagisawa K. Sequence organization and gene expression of pGD1, a plasmid found in a wild isolate of Dictyostelium. Nucleic Acids Res 1989; 17:1395-408. [PMID: 2537957 PMCID: PMC331811 DOI: 10.1093/nar/17.4.1395] [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: 01/01/2023] Open
Abstract
We have determined the complete nucleotide sequence of pDG1, a plasmid found in a wild isolate of Dictyostelium. The 4439-bp long pDG1 contains only one, 2718-bases-long, open reading frame (ORF) and nearly perfect inverted repeats of 551 bp and 552 bp. Northern-blot analysis showed that only one 2.7-kb poly (A)+ RNA transcript was expressed at a maximum level, 2 h (early aggregation stage) after the onset of development. The expression of this transcript was suppressed by the addition of cAMP. In the upstream region of the ORF, there are several putative consensus sequences, e.g. (1) TGACTTAGAA-AAATT which is a putative site for cleavage by topoisomerase I, and (2) TGACGACA which may be a cAMP-responsive element, found in several genes that are regulated by cAMP at the level of transcription. A possible mechanism of the partitioning of pDG1 into daughter cells is discussed.
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Affiliation(s)
- H Orii
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan
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Hurley DL, Skantar AM, Deering RA, Skantarz AM. Nuclear DNA synthesis is blocked by UV irradiation in Dictyostelium discoideum. Mutat Res 1989; 217:25-32. [PMID: 2911264 DOI: 10.1016/0921-8777(89)90032-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have used a thymidine auxotroph of the simple eukaryote, Dictyostelium discoideum and alkaline sucrose gradients of isolated nuclei to study alterations in DNA synthesis following irradiation of replicating haploid cells with 254 nm UV light. Three responses were characterized using pulse-chase protocols: (1) Lags in DNA synthesis as measured by the amount of label incorporated were 4, 9, and 20 h after 10, 50, and 200 J/m2. (2) The DNA synthesized during a 15-min pulse immediately after irradiation was of lower single strand molecular weight: 7, 3.5, and 3 x 10(6) dalton after 0, 50, and 200 J/m2. (3) The time required for maturation of the nascent DNA to full-sized single strands of about 2 x 10(8) dalton was 45-50 min for unirradiated cells, 3 h after 10 J/m2, and 20 h after 200 J/m2. The DNA of the irradiated cells did not mature uniformly during these delays; instead, a period of no increase in size was followed by a rapid, nearly control rate of maturation. We conclude: (a) at least some UV lesions block elongation of replicons; (b) the elongation of the replicons and their subsequent joining to yield mature high molecular weight DNA occurs after most of the lesions are repaired; (c) the timing of the different aspects of recovery suggest that initiation of replication is also inhibited.
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Affiliation(s)
- D L Hurley
- Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802
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