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Cole E, Gaertig J. Anterior-posterior pattern formation in ciliates. J Eukaryot Microbiol 2022; 69:e12890. [PMID: 35075744 PMCID: PMC9309198 DOI: 10.1111/jeu.12890] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/06/2022] [Accepted: 01/17/2022] [Indexed: 11/29/2022]
Abstract
As single cells, ciliates build, duplicate, and even regenerate complex cortical patterns by largely unknown mechanisms that precisely position organelles along two cell‐wide axes: anterior–posterior and circumferential (left–right). We review our current understanding of intracellular patterning along the anterior–posterior axis in ciliates, with emphasis on how the new pattern emerges during cell division. We focus on the recent progress at the molecular level that has been driven by the discovery of genes whose mutations cause organelle positioning defects in the model ciliate Tetrahymena thermophila. These investigations have revealed a network of highly conserved kinases that are confined to either anterior or posterior domains in the cell cortex. These pattern‐regulating kinases create zones of cortical inhibition that by exclusion determine the precise placement of organelles. We discuss observations and models derived from classical microsurgical experiments in large ciliates (including Stentor) and interpret them in light of recent molecular findings in Tetrahymena. In particular, we address the involvement of intracellular gradients as vehicles for positioning organelles along the anterior‐posterior axis.
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Affiliation(s)
- Eric Cole
- Biology Department, St. Olaf College, Northfield, MN, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
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Jiang YY, Maier W, Chukka UN, Choromanski M, Lee C, Joachimiak E, Wloga D, Yeung W, Kannan N, Frankel J, Gaertig J. Mutual antagonism between Hippo signaling and cyclin E drives intracellular pattern formation. J Cell Biol 2020; 219:e202002077. [PMID: 32642758 PMCID: PMC7480119 DOI: 10.1083/jcb.202002077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/11/2020] [Accepted: 06/04/2020] [Indexed: 11/23/2022] Open
Abstract
Not much is known about how organelles organize into patterns. In ciliates, the cortical pattern is propagated during "tandem duplication," a cell division that remodels the parental cell into two daughter cells. A key step is the formation of the division boundary along the cell's equator. In Tetrahymena thermophila, the cdaA alleles prevent the formation of the division boundary. We find that the CDAA gene encodes a cyclin E that accumulates in the posterior cell half, concurrently with accumulation of CdaI, a Hippo/Mst kinase, in the anterior cell half. The division boundary forms between the margins of expression of CdaI and CdaA, which exclude each other from their own cortical domains. The activities of CdaA and CdaI must be balanced to initiate the division boundary and to position it along the cell's equator. CdaA and CdaI cooperate to position organelles near the new cell ends. Our data point to an intracellular positioning mechanism involving antagonistic Hippo signaling and cyclin E.
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Affiliation(s)
- Yu-Yang Jiang
- Department of Cellular Biology, University of Georgia, Athens, GA
| | - Wolfgang Maier
- Bioinformatics, University of Freiburg, Freiburg, Germany
| | | | | | - Chinkyu Lee
- Department of Cellular Biology, University of Georgia, Athens, GA
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Wayland Yeung
- Institute of Bioinformatics, University of Georgia, Athens, GA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, GA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Joseph Frankel
- Department of Biology, University of Iowa, Iowa City, IA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA
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Jiang YY, Maier W, Baumeister R, Minevich G, Joachimiak E, Ruan Z, Kannan N, Clarke D, Frankel J, Gaertig J. The Hippo Pathway Maintains the Equatorial Division Plane in the Ciliate Tetrahymena. Genetics 2017; 206:873-888. [PMID: 28413159 PMCID: PMC5499192 DOI: 10.1534/genetics.117.200766] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/29/2017] [Indexed: 12/30/2022] Open
Abstract
The mechanisms that govern pattern formation within the cell are poorly understood. Ciliates carry on their surface an elaborate pattern of cortical organelles that are arranged along the anteroposterior and circumferential axes by largely unknown mechanisms. Ciliates divide by tandem duplication: the cortex of the predivision cell is remodeled into two similarly sized and complete daughters. In the conditional cdaI-1 mutant of Tetrahymena thermophila, the division plane migrates from its initially correct equatorial position toward the cell's anterior, resulting in unequal cell division, and defects in nuclear divisions and cytokinesis. We used comparative whole genome sequencing to identify the cause of cdaI-1 as a mutation in a Hippo/Mst kinase. CdaI is a cortical protein with a cell cycle-dependent, highly polarized localization. Early in cell division, CdaI marks the anterior half of the cell, and later concentrates at the posterior end of the emerging anterior daughter. Despite the strong association of CdaI with the new posterior cell end, the cdaI-1 mutation does not affect the patterning of the new posterior cortical organelles. We conclude that, in Tetrahymena, the Hippo pathway maintains an equatorial position of the fission zone, and, by this activity, specifies the relative dimensions of the anterior and posterior daughter cell.
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Affiliation(s)
- Yu-Yang Jiang
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | - Wolfgang Maier
- Bio3/Bioinformatics and Molecular Genetics (Faculty of Biology) and ZMBZ (Faculty of Medicine)
| | - Ralf Baumeister
- Bio3/Bioinformatics and Molecular Genetics (Faculty of Biology) and ZMBZ (Faculty of Medicine)
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, 79104 Germany
| | - Gregory Minevich
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, New York 10032
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Zheng Ruan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Diamond Clarke
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | - Joseph Frankel
- Department of Biology, University of Iowa, Iowa City, Iowa 52242
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
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Wloga D, Frankel J. From Molecules to Morphology: Cellular Organization of Tetrahymena thermophila. Methods Cell Biol 2012; 109:83-140. [DOI: 10.1016/b978-0-12-385967-9.00005-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Abstract
The ciliate Tetrahymena thermophila can be said to undergo a variety of developmental programs. During vegetative growth, cells coordinate a variety of cell-cycle operations including macronuclear DNA synthesis and a-mitotic fission, micronuclear DNA synthesis and mitosis, cytokinesis and an elaborate program of cortical morphogenesis that replicates the cortical organelles. When starved, cells undergo oral replacement, transformation into fast-swimming dispersal forms or, when encountering cells of a complementary mating type, conjugation. Conjugation involves a 12 hour program of meiosis, mitosis, nuclear exchange and karyogamy, and two postzygotic divisions of the fertilization nucleus. This chapter reviews experimental data exploring the developmental dependencies associated with both vegetative and conjugal development.
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Long H, Zufall RA. Diverse modes of reproduction in the marine free-living ciliate Glauconema trihymene. BMC Microbiol 2010; 10:108. [PMID: 20388205 PMCID: PMC2873486 DOI: 10.1186/1471-2180-10-108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 04/13/2010] [Indexed: 11/16/2022] Open
Abstract
Background Most free-living ciliates reproduce by equal fission or budding during vegetative growth. In certain ciliates, reproduction occurs inside the cyst wall, viz. reproductive cysts, but more complex reproductive strategies have generally been thought to be confined to parasitic or symbiotic species, e.g. Radiophrya spp. Results In addition to equal fission, asymmetric binary division and reproductive cysts were discovered in the free-living bacterivorous scuticociliate Glauconema trihymene Thompson, 1966. Asymmetric division is an innate physiological state that can be induced by sufficient food, and the higher the food concentration, the longer the asymmetric division persists. During asymmetric division, nuclear and somatic structures divide with transiently arrested cytokinesis and variable positioning of macronuclei. Phylogenetic analysis, based on the small subunit of ribosomal DNA (SSU rDNA) sequences, showed that the G. trihymene isolate studied here nests with typical scuticociliates and is paraphyletic to both the symbiotic apostome and astome ciliates, some of which also produce progeny by asymmetric division. Conclusions The asymmetric division in G. trihymene has no precedent among undisturbed free-living ciliates. The coexistence of multiple modes of reproduction may represent a previously undescribed reproductive strategy for ciliates living on food patches in coastal waters. This may also be indicative of similar reproductive strategies among other polyphenic ciliates, which have not been intensively studied. Asymmetric division provides a special opportunity for studying ciliates' phenotypic plasticity and may also illuminate the origins of multicellularity.
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Affiliation(s)
- Hongan Long
- Department of Biology and Biochemistry, University of Houston, Houston TX 77204-5001, USA.
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Nested genes CDA12 and CDA13 encode proteins associated with membrane trafficking in the ciliate Tetrahymena thermophila. EUKARYOTIC CELL 2009; 8:899-912. [PMID: 19286988 DOI: 10.1128/ec.00342-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We describe a novel pair of nested genes, CDA12 and CDA13, from Tetrahymena thermophila. Both are implicated in membrane trafficking associated with cell division and conjugation. Green fluorescent protein localization reveals Cda12p decoration of diverse membrane-bound compartments, including mobile, subcortical tubulovesicular compartments; perinuclear vesicles; and candidates for recycling endosomes. Cda13p decorates intracellular foci located adjacent to cortically aligned mitochondria and their neighboring Golgi networks. The expression of antisense CDA12 RNA in transformants produces defects in cytokinesis, macronuclear segregation, and the processing of pinosomes to downstream compartments. Antisense CDA13 RNA expression produces a conjugation phenotype, resulting in the failure of mating pairs to separate, as well as failures in postconjugation cytokinesis and macronuclear fission. This study offers insight into the membrane trafficking events linking endosome and Golgi network activities, cytokinesis, and karyokinesis and the unique membrane-remodeling events that accompany conjugation in the ciliate T. thermophila. We also highlight an unusual aspect of genome organization in Tetrahymena, namely, the existence of nested, antisense genes.
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Kirk KE, Christ C, McGuire JM, Paul AG, Vahedi M, Stuart KR, Cole ES. Abnormal micronuclear telomeres lead to an unusual cell cycle checkpoint and defects in Tetrahymena oral morphogenesis. EUKARYOTIC CELL 2008; 7:1712-23. [PMID: 18469136 PMCID: PMC2568063 DOI: 10.1128/ec.00393-07] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Accepted: 04/16/2008] [Indexed: 11/20/2022]
Abstract
Telomere mutants have been well studied with respect to telomerase and the role of telomere binding proteins, but they have not been used to explore how a downstream morphogenic event is related to the mutated telomeric DNA. We report that alterations at the telomeres can have profound consequences on organellar morphogenesis. Specifically, a telomerase RNA mutation termed ter1-43AA results in the loss of germ line micronuclear telomeres in the binucleate protozoan Tetrahymena thermophila. These cells also display a micronuclear mitotic arrest, characterized by an extreme delay in anaphase with an elongated, condensed chromatin and a mitotic spindle apparatus. This anaphase defect suggests telomere fusions and consequently a spindle rather than a DNA damage checkpoint. Most surprisingly, these mutants exhibit unique, dramatic defects in the formation of the cell's oral apparatus. We suggest that micronuclear telomere loss leads to a "dynamic pause" in the program of cortical development, which may reveal an unusual cell cycle checkpoint.
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Affiliation(s)
- Karen E Kirk
- Department of Biology, Lake Forest College, Lake Forest, Illinois 60045, USA.
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What do genic mutations tell us about the structural patterning of a complex single-celled organism? EUKARYOTIC CELL 2008; 7:1617-39. [PMID: 18658256 DOI: 10.1128/ec.00161-08] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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NG STEPHENF. Interdependence of Cell Cycle Events inTetrahymena thermophila: Formation of Contractile Vacuole Pore and Fission Gap in Ciliary Meridians*. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1979.tb04199.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Williams NE, Tsao CC, Bowen J, Hehman GL, Williams RJ, Frankel J. The actin gene ACT1 is required for phagocytosis, motility, and cell separation of Tetrahymena thermophila. EUKARYOTIC CELL 2006; 5:555-67. [PMID: 16524910 PMCID: PMC1398063 DOI: 10.1128/ec.5.3.555-567.2006] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A previously identified Tetrahymena thermophila actin gene (C. G. Cupples and R. E. Pearlman, Proc. Natl. Acad. Sci. USA 83:5160-5164, 1986), here called ACT1, was disrupted by insertion of a neo3 cassette. Cells in which all expressed copies of this gene were disrupted exhibited intermittent and extremely slow motility and severely curtailed phagocytic uptake. Transformation of these cells with inducible genetic constructs that contained a normal ACT1 gene restored motility. Use of an epitope-tagged construct permitted visualization of Act1p in the isolated axonemes of these rescued cells. In ACT1Delta mutant cells, ultrastructural abnormalities of outer doublet microtubules were present in some of the axonemes. Nonetheless, these cells were still able to assemble cilia after deciliation. The nearly paralyzed ACT1Delta cells completed cleavage furrowing normally, but the presumptive daughter cells often failed to separate from one another and later became reintegrated. Clonal analysis revealed that the cell cycle length of the ACT1Delta cells was approximately double that of wild-type controls. Clones could nonetheless be maintained for up to 15 successive fissions, suggesting that the ACT1 gene is not essential for cell viability or growth. Examination of the cell cortex with monoclonal antibodies revealed that whereas elongation of ciliary rows and formation of oral structures were normal, the ciliary rows of reintegrated daughter cells became laterally displaced and sometimes rejoined indiscriminately across the former division furrow. We conclude that Act1p is required in Tetrahymena thermophila primarily for normal ciliary motility and for phagocytosis and secondarily for the final separation of daughter cells.
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Affiliation(s)
- Norman E Williams
- Department of Biological Sciences, The University of Iowa, 143 Biology Bldg., Iowa City, IA 52242, USA
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Fujiu K, Numata O. Localization of microtubules during macronuclear division in Tetrahymena and possible involvement of macronuclear microtubules in 'amitotic' chromatin distribution. Cell Struct Funct 2004; 24:401-4. [PMID: 15216897 DOI: 10.1247/csf.24.401] [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] [Indexed: 11/11/2022] Open
Abstract
The ciliated protozoa Tetrahymena contains two nuclei, a micronucleus and a macronucleus. In the vegetatively growing cell, the macronucleus divides amitotic while the micronucleus divides by mitosis. It has been indicated that microtubules are involved in macronuclear division and microtubules are observed to exist in the dividing macronucleus. To clarify the localization and the organization of microtubules in the amitotic dividing macronuclei, we used immunofluorescent staining technique. The microtubules were observed in the cytoplasm and macronucleus. The microtubules were organized and dynamically changed their distribution throughout the macronuclear division. We suggest a possibility that these microtubules are involved in 'amitotic' distribution of chromatin throughout the macronuclear division.
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Affiliation(s)
- K Fujiu
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
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Zhang H, Huang X, Tang L, Zhang QJ, Frankel J, Berger JD. A cyclin-dependent protein kinase homologue associated with the basal body domains in the ciliate Tetrahymena thermophila. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1591:119-128. [PMID: 12183062 DOI: 10.1016/s0167-4889(02)00258-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The tight coupling between cell cycle progression and morphogenetic development in the unicellular ciliates presents a unique model system for examination of the roles of Cdks in developmental processes. We here describe the isolation and characterization of the first cyclin-dependent kinase (Cdk) homologue, TtCdk1, from Tetrahymena thermophila. TtCdk1 corresponds to the larger of the two polypeptides recognized by anti-PSTAIRE antibody in a whole cell lysate, which differ from each other in their affinity for yeast p13(suc1) protein. In contrast to the constant protein expression levels of typical eukaryotic Cdks, the TtCdk1 protein level fluctuates periodically over the vegetative cell cycle, reaching a maximum at the end of the cell cycle, correlating with its histone H1 kinase activity. Its association with the membrane-skeletal domains that surround mature, but not nascent, basal bodies in the cell cortex suggests that TtCdk1 plays a role in the regulation of cortical morphogenesis in T. thermophila. A partial TtCDK1 knockout cell line constructed through somatic biolistic transformation resulted in a reduction of the regularity of the rows of basal bodies plus an additional effect on chromatin condensation in both macro- and micronuclei. Unlike the situations in higher eukaryotic cells, no apparent effect on basal body duplication was found upon disruption of the TtCDK1 gene.
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Affiliation(s)
- Hong Zhang
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
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Numata O, Gonda K. Determination of division plane and organization of contractile ring in Tetrahymena. Cell Struct Funct 2001; 26:593-601. [PMID: 11942614 DOI: 10.1247/csf.26.593] [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: 11/11/2022] Open
Abstract
In the molecular mechanism of division plane determination and contractile ring formation, Tetrahymena 85kDa protein (p85) is localized to the presumptive division plane before the formation of the contractile ring. p85 directly interacts with Tetrahymena calmodulin (CaM) in a Ca2+-dependent manner, and p85 and CaM colocalize in the division furrow. A Ca2+/CaM inhibitor N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide HCI (W7) inhibits the direct interaction between p85 and Ca2+/CaM. W7 also inhibits the localization of p85 and CaM to the division plane, and the formation of the contractile ring and division furrow. In addition, p85 binds to G-actin in a Ca2+/CaM dependent manner, but does not bind F-actin. Tetrahymena profilin is localized to division furrow and binds Tetrahymena elongation factor-1alpha (EF-1alpha). EF-1alpha, which induces bundling of Tetrahymena F-actin, is also localized to the division furrow during cytokinesis. The evidence also indicates that Ca2+/CaM inhibits the F-actin-bundling activity of EF-1alpha, and that EF-1alpha and CaM colocalize in the division furrow. In this review, we propose that the Ca2+/CaM signal and its target protein p85 cooperatively regulate the determination of the division plane and the initiation of the contractile ring formation, and that profilin and a Ca2+/CaM-sensitive actin-bundling protein, EF-1alpha, play pivotal roles in regulating the organization of the contractile ring microfilaments.
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Affiliation(s)
- O Numata
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
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Numata O, Gonda K, Watanabe A, Kurasawa Y. Cytokinesis in Tetrahymena: determination of division plane and organization of contractile ring. Microsc Res Tech 2000; 49:127-35. [PMID: 10816251 DOI: 10.1002/(sici)1097-0029(20000415)49:2<127::aid-jemt4>3.0.co;2-k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A protein, Tetrahymena p85, is localized to the presumptive division plane before the formation of the contractile ring. p85 directly interacts with Tetrahymena calmodulin (CaM) in a Ca(2+)-dependent manner, and p85 and CaM colocalize in the division furrow. A Ca(2+)/CaM inhibitor N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide HCl (W7) inhibits the direct interaction between p85 and Ca(2+)/CaM. W7 also inhibits the localization of p85 and CaM to the division plane, and the formation of the contractile ring and division furrow. Tetrahymena fimbrin and elongation factor-1a (EF-1alpha), which induce bundling of Tetrahymena F-actin, are also localized to the division furrow during cytokinesis. The Tetrahymena fimbrin has two actin-binding domains, but lacks the EF-hand Ca(2+)-binding motif, suggesting that Tetrahymena fimbrin probably cross-links actin filaments in a Ca(2+)- insensitive manner during cytokinesis. The evidence also indicates that Ca(2+)/CaM inhibits the F-actin-bundling activity of EF-1alpha; and EF-1alpha and CaM colocalize in the division furrow. In this review, we propose that the Ca(2+)/CaM signal and its target protein p85 cooperatively regulate the determination of the division plane, and that a Ca(2+)-insensitive actin-bundling protein, Tetrahymena fimbrin, and a Ca(2+)/CaM-sensitive actin-bundling protein, EF-1alpha, play pivotal roles in regulating the organization of the contractile ring microfilaments.
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Affiliation(s)
- O Numata
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
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16
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Gonda K, Katoh M, Hanyu K, Watanabe Y, Numata O. Ca(2+)/calmodulin and p85 cooperatively regulate an initiation of cytokinesis in Tetrahymena. J Cell Sci 1999; 112 ( Pt 21):3619-26. [PMID: 10523498 DOI: 10.1242/jcs.112.21.3619] [Citation(s) in RCA: 25] [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
Tetrahymena p85 differs in mobility in two-dimensional SDS-polyacrylamide gel electrophoresis between wild-type and temperature-sensitive cell-division-arrest mutant cdaA1 cell extracts, and is localized to the presumptive division plane before the formation of the division furrow. The p85 contained three identical sequences which show homology to the calmodulin binding site of Ca(2+)/calmodulin dependent protein kinase Type II in Saccharomyces cerevisiae. We found the p85 directly interacts with Tetrahymena calmodulin in a Ca(2+)-dependent manner, using a co-sedimentation assay. We next examined the localization of p85 and calmodulin during cytokinesis using indirect immunofluorescence. The results showed that both proteins colocalize in the division furrow. This is the first observation that calmodulin is localized in the division furrow. Moreover, the direct interaction between p85 and Ca(2+)/calmodulin was inhibited by Ca(2+)/calmodulin inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide HCl. When the cells were treated with the drug just before the beginning of cytokinesis, the drug also inhibited the localization of p85 and calmodulin to the division plane, and the formation of the contractile ring and division furrow. Therefore, we propose that the Ca(2+)/calmodulin signal and its target protein p85 cooperatively regulate an initiation of cytokinesis and may be also concerned with the progression of cytokinesis in Tetrahymena.
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Affiliation(s)
- K Gonda
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
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Gonda K, Nishibori K, Ohba H, Watanabe A, Numata O. Molecular cloning of the gene for p85 that regulates the initiation of cytokinesis in Tetrahymena. Biochem Biophys Res Commun 1999; 264:112-8. [PMID: 10527850 DOI: 10.1006/bbrc.1999.1354] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tetrahymena p85 is localized to the presumptive division plane before division furrow formation; its molecular weight in SDS-polyacrylamide gel electrophoresis differs in wild-type and temperature-sensitive cell-division-arrest mutant cdaA1 cells. At the restrictive temperature, p85 localization and division furrow formation are not observed in cdaA1 cells. In this study, we purified p85 and cloned a wild-type p85 cDNA. The deduced amino acid sequence of p85 was composed mainly of two kinds of repeat sequences. One of these contained regions homologous to a calmodulin-binding site and a part of actin, and the other contained a region homologous to a part of a cdc2 kinase homologue. Moreover, we cloned a cDNA encoding the cdaA1 p85. There was no difference in the predicted amino acid sequences of wild-type and cdaA1 p85, suggesting that the difference in molecular weight between p85 in wild-type and mutant cells is caused by a disorder of posttranslational-modification mechanisms of p85 in the cdaA1 cell.
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Affiliation(s)
- K Gonda
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
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18
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Affiliation(s)
- J Frankel
- Department of Biological Sciences, University of Iowa, Iowa City 52242, USA
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Numata O, Suzuki H, Ohba H, Watanabe Y. The mutant gene product of a Tetrahymena cell-division-arrest mutant cdaA is localized in the accessory structure of specialized basal body close to the division furrow. Zoolog Sci 1995; 12:133-5. [PMID: 7795488 DOI: 10.2108/zsj.12.133] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A division arrest mutant, cdaA, of Tetrahymena thermophila is known to have a temperature sensitive-defect in the determination of the division plane, and its gene product had been shown to be a protein designated as p85 (Mr = 85,000; pI = 4.7). Here the localization of p85 was shown to be the accessary structure of specialized basal body close to the division furrow by immunoelectron microscopy using anti-p85 antiserum.
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Affiliation(s)
- O Numata
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan
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Romero DP, Blackburn EH. Circular rDNA replicons persist in Tetrahymena thermophila transformants synthesizing GGGGTC telomeric repeats. J Eukaryot Microbiol 1995; 42:32-43. [PMID: 7537144 DOI: 10.1111/j.1550-7408.1995.tb01537.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Site-directed mutagenesis of the telomerase RNA from Tetrahymena thermophila was used previously to demonstrate the templating function of a sequence within this RNA; this sequence specifies the sequence of telomeric DNA in vivo. The possible functional importance of a phylogenetically conserved nucleotide outside the telomerase RNA template region was investigated by a similar experimental approach. The telomerase RNA gene was altered by site-directed mutagenesis, cloned in a circular selectable transformation vector consisting of an rRNA gene carrying a selectable drug resistance marker, and introduced into macronuclei of vegetatively dividing Tetrahymena thermophila by microinjection. Changing an invariant A to U at position 16 of the telomerase RNA (A16U) had no effect detectable by phenotype on telomerase function in vivo. However these experiments showed that a telomerase template alteration that dictates the synthesis of the mutant telomeric DNA sequence GGGGTC leads to a profound change in the population of rDNA replicons. The addition of GGGGTC mutant repeats leads to selective pressure for the loss of high copy linear rDNA, and the rRNA genes are maintained in the form of the circular rDNA replicons introduced during transformation.
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Affiliation(s)
- D P Romero
- Department of Pharmacology, School of Medicine, University of Minnesota, Minneapolis 55455
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Ohba H, Hirono M, Edamatsu M, Watanabe Y. Timing of formation ofTetrahymena contractile ring microfilaments investigated by inhibition with skeletal muscle actin. ACTA ACUST UNITED AC 1992. [DOI: 10.1002/dvg.1020130306] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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22
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Kaczanowska J, Buzanska L, Frontczak M. The influence of fission line expression on the number and positioning of oral primordia in the cdaA1 mutant of Tetrahymena thermophila. DEVELOPMENTAL GENETICS 1992; 13:216-22. [PMID: 1499162 DOI: 10.1002/dvg.1020130307] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
During cytokinesis, furrowing creates new boundaries for daughter cells. Following a shift to a restrictive temperature, cells of the temperature-sensitive cell-division-arrest (cdaA1) mutant of Tetrahymena thermophila complete development of the oral apparatus for the prospective posterior daughter cell before becoming arrested in cytokinesis. When maintained under weak restrictive conditions (35 degrees C), some of the chains were arrested prior to the start of fission line formation (D-shaped chains), whereas others manifested rudimentary unilateral furrowing on the ventral side (B-shaped chains). In their second cell cycle following the temperature shift, the D-shaped chains usually formed only one oral primordium, at a position highly correlated with the length of the entire chain. The B-shaped chains always produced two separate oral primordia, located at irregular positions anterior and posterior to the division furrow, often close to the posterior oral apparatus produced during the first cycle. These results suggest that the formation of the fission line sets a reference boundary to assess the number of oral primordia and influence their position, that appear during subsequent morphogenetic episodes. They also indicate that, during cell division cycles, pre-existing oral apparatuses do not strongly inhibit the formation of new oral apparatuses in their close vicinity.
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Abstract
Telomeres are specialized chromatin domains located at the ends of chromosomes. They are involved in chromosome replication, stability and localization in the nucleus. In addition to these functions, recent work suggests that telomeres are involved in such superficially diverse cellular phenomena as ageing, cancer, nuclear architecture and nuclear/cellular division.
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Affiliation(s)
- E R Henderson
- Department of Zoology and Genetics, Iowa State University, Ames 50011
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Watanabe Y, Ohba H, Hirono M, Yasuda T. Analysis of furrow formation and furrowing during cell division in Tetrahymena using cell-division-arrest mutants. Ann N Y Acad Sci 1990; 582:166-78. [PMID: 2192593 DOI: 10.1111/j.1749-6632.1990.tb21677.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Y Watanabe
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan
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Yu GL, Bradley JD, Attardi LD, Blackburn EH. In vivo alteration of telomere sequences and senescence caused by mutated Tetrahymena telomerase RNAs. Nature 1990; 344:126-32. [PMID: 1689810 DOI: 10.1038/344126a0] [Citation(s) in RCA: 457] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mutating the CAACCCCAA sequence in the RNA component of telomerase causes the synthesis in vivo of new telomere sequences corresponding to the mutated RNA sequence, demonstrating that the telomerase contains the template for telomere synthesis. These mutations also lead to nuclear and cell division defects, and senescence, establishing an essential role for telomerase in vivo.
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Affiliation(s)
- G L Yu
- Department of Molecular and Cell Biology, University of California, Berkeley
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Bużańska L, Gregory DW, Wheatley DN. Protrusion formation in the cell division-arrested mutantTetrahymena thermophila cdaA1: Some rules governing cytoskeletal growth. ACTA ACUST UNITED AC 1989. [DOI: 10.1002/jez.1402510105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hjelm KK. Is non-genic inheritance involved in carcinogenesis? A cytotactic model of transformation. J Theor Biol 1986; 119:89-101. [PMID: 3713226 DOI: 10.1016/s0022-5193(86)80053-4] [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: 01/07/2023]
Abstract
There is convincing evidence that the patterns formed by microtubules and by other fibres and organelles in ciliates are partly determined by non-genic inherited information, the so-called cytotactic information. There is also some evidence that this exists in metazoan cells and is perhaps involved in neoplastic transformation. On this background a cytotactic model of transformation which allows new interpretation of several characteristics of cancer cells has been developed. It proposes (a) that most cells contain cytotactic information, (b) that mechanisms to repair modifications of this information exist, and (c) that transformation may result when the cytotactic information is modified beyond repair. The model further proposes that (d) the modified cytotactic information is unevenly distributed between daughter cells at the following divisions so that cells with abnormal patterns, increasing pleomorphy and malignancy, and possibly altered gene functions are formed. The cytotactic transformation is proposed to take place in one or in two steps and to be inducible not only by many usual carcinogens but also by for example aborted cell divisions. A cytotactic interpretation of cancers induced by asbestos and of certain other observations is attempted.
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Kaczanowski A, Gaertig J, Kubiak J. Effect of the antitubulin drug nocodazole on meiosis and postmeiotic development in Tetrahymena thermophila. Induction of achiasmatic meiosis. Exp Cell Res 1985; 158:244-56. [PMID: 3996478 DOI: 10.1016/0014-4827(85)90447-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Nocodazole (ND), a potent antitubulin drug, can be used to dissect the steps of meiosis in Tetrahymena, presumably by interfering with the assembly of microtubules. Its effects depend upon the time during conjugation at which the drug is applied. When applied prior to the elongation of the micronucleus into the characteristic 'crescent' configuration, no crescent is formed and the chromosomes of prepachytene and pachytene condense into spherical nuclei. If ND is applied after micronuclear elongation has begun, but before it is fully elongated, the chromosomes fail to synapse and appear in metaphase I as unpaired monovalents. In contrast, the metaphase I chromosomes appear as bivalents when ND is applied later, during or after the crescent has reached its maximum elongation. Still later, application of ND inhibits chromosome movements during anaphase and telophase of either meiotic division, but does not prevent separation of kinetochores. In some of the blocked restitutive nuclei an additional round of chromosome replication occurs, corresponding to the third pregamic division in normal conjugation. The hyperploid micronuclei produced by such treatment may be useful in certain genetic manipulations and in studying the regulation of nuclear DNA content.
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Mayo KA, Orias E. Lack of expression of micronuclear genes determining two different enzymatic activities in Tetrahymena thermophila. Differentiation 1985. [DOI: 10.1111/j.1432-0436.1985.tb00828.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Frankel J, Nelsen EM, Martel E. Development of the ciliature of Tetrahymena thermophila. II. Spatial subdivision prior to cytokinesis. Dev Biol 1981; 88:39-54. [PMID: 7286447 DOI: 10.1016/0012-1606(81)90217-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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31
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Roberts CT, Morse DE. Galactokinase-deficient mutants of Tetrahymena thermophila: selection and characterization. MOLECULAR & GENERAL GENETICS : MGG 1980; 180:129-34. [PMID: 6934362 DOI: 10.1007/bf00267361] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We have isolated a series of mutants of Tetrahymena thermophila which are resistant to inhibition of growth by the galactose analog, 2-deoxygalactose. These mutants were obtained after mutagenesis with nitrosoguanidine and the induction of cytogamy to permit the recovery of recessive mutations induced in the germline micronucleus. Resistance to 2-deoxygalactose is correlated with a decreased rate of growth in galactose minimal medium and greatly reduced levels of galactokinase. The resistant phenotype of the mutants is apparently due to the galactokinase deficiency, which prevents the accumulation of toxic phosphorylated metabolites of 2-deoxygalactose. Genetic analyses reveal that the 2-deoxygalactose resistance alleles segregate as single Mendelian loci. The galactokinase-deficient strains described here represent the first mutants in this organism for which the biochemical basis of the mutant phenotype is known. These mutants, as well as others isolated similarly, should be of value in the elucidation of the mechanisms governing galactokinase gene regulation and in improving techniques of selection for other recessive mutations in Tetrahymena.
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Yasuda T, Numata O, Ohnishi K, Watanabe Y. A contractile ring and cortical changes found in the dividing Tetrahymena pyriformis. Exp Cell Res 1980; 128:407-17. [PMID: 6773789 DOI: 10.1016/0014-4827(80)90076-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Aufderheide KJ, Frankel J, Williams NE. Formation and positioning of surface-related structures in protozoa. Microbiol Rev 1980; 44:252-302. [PMID: 6770243 PMCID: PMC373179 DOI: 10.1128/mr.44.2.252-302.1980] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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34
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Hamilton EP, Suhr-Jessen PB. Autoradiographic evidence for self-fertilization in Tetrahymena thermophila. Exp Cell Res 1980; 126:391-6. [PMID: 7363953 DOI: 10.1016/0014-4827(80)90278-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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35
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Cleffmann G, Frankel J. The DNA replication schedule is not affected in a division blocked mutant of Tetrahymena thermophila. Exp Cell Res 1978; 117:191-4. [PMID: 720404 DOI: 10.1016/0014-4827(78)90441-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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