1
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Pinello JF, Loidl J, Seltzer ES, Cassidy-Hanley D, Kolbin D, Abdelatif A, Rey FA, An R, Newberger NJ, Bisharyan Y, Papoyan H, Byun H, Aguilar HC, Lai AL, Freed JH, Maugel T, Cole ES, Clark TG. Novel requirements for HAP2/GCS1-mediated gamete fusion in Tetrahymena. iScience 2024; 27:110146. [PMID: 38904066 PMCID: PMC11187246 DOI: 10.1016/j.isci.2024.110146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 04/29/2024] [Accepted: 05/27/2024] [Indexed: 06/22/2024] Open
Abstract
The ancestral gamete fusion protein, HAP2/GCS1, plays an essential role in fertilization in a broad range of taxa. To identify factors that may regulate HAP2/GCS1 activity, we screened mutants of the ciliate Tetrahymena thermophila for behaviors that mimic Δhap2/gcs1 knockout phenotypes in this species. Using this approach, we identified two new genes, GFU1 and GFU2, whose products are necessary for membrane pore formation following mating type recognition and adherence. GFU2 is predicted to be a single-pass transmembrane protein, while GFU1, though lacking obvious transmembrane domains, has the potential to interact directly with membrane phospholipids in the cytoplasm. Like Tetrahymena HAP2/GCS1, expression of GFU1 is required in both cells of a mating pair for efficient fusion to occur. To explain these bilateral requirements, we propose a model that invokes cooperativity between the fusion machinery on apposed membranes of mating cells and accounts for successful fertilization in Tetrahymena's multiple mating type system.
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Affiliation(s)
- Jennifer F. Pinello
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Josef Loidl
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Ethan S. Seltzer
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Donna Cassidy-Hanley
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Daniel Kolbin
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Anhar Abdelatif
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Félix A. Rey
- Unité de Virologie Structurale, Institut Pasteur, 75724 Paris, France
- CNRS UMR 3569, 75724 Paris, France
| | - Rocky An
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Nicole J. Newberger
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Yelena Bisharyan
- Office of Technology Development, Harvard University, Cambridge, MA 02138, USA
| | - Hayk Papoyan
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Haewon Byun
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Hector C. Aguilar
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Alex L. Lai
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, USA
| | - Jack H. Freed
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, USA
| | - Timothy Maugel
- Department of Biology, Laboratory for Biological Ultrastructure, University of Maryland, College Park, MD 20742, USA
| | - Eric S. Cole
- Biology Department, St. Olaf College, Northfield, MN 55057, USA
| | - Theodore G. Clark
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
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2
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Nicot S, Gillard G, Impheng H, Joachimiak E, Urbach S, Mochizuki K, Wloga D, Juge F, Rogowski K. A family of carboxypeptidases catalyzing α- and β-tubulin tail processing and deglutamylation. SCIENCE ADVANCES 2023; 9:eadi7838. [PMID: 37703372 PMCID: PMC10499314 DOI: 10.1126/sciadv.adi7838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/10/2023] [Indexed: 09/15/2023]
Abstract
Tubulin posttranslational modifications represent an important mechanism involved in the regulation of microtubule functions. The most widespread among them are detyrosination, α∆2-tubulin, and polyglutamylation. Here, we describe a family of tubulin-modifying enzymes composed of two closely related proteins, KIAA0895L and KIAA0895, which have tubulin metallocarboxypeptidase activity and thus were termed TMCP1 and TMCP2, respectively. We show that TMCP1 (also known as MATCAP) acts as α-tubulin detyrosinase that also catalyzes α∆2-tubulin. In contrast, TMCP2 preferentially modifies βI-tubulin by removing three amino acids from its C terminus, generating previously unknown βI∆3 modification. We show that βI∆3-tubulin is mostly found on centrioles and mitotic spindles and in cilia. Moreover, we demonstrate that TMCPs also remove posttranslational polyglutamylation and thus act as tubulin deglutamylases. Together, our study describes the identification and comprehensive biochemical analysis of a previously unknown type of tubulin-modifying enzymes involved in the processing of α- and β-tubulin C-terminal tails and deglutamylation.
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Affiliation(s)
- Simon Nicot
- Tubulin Code team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
| | - Ghislain Gillard
- Tubulin Code team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
| | - Hathaichanok Impheng
- Department of Physiology, Faculty of Medical science, Naresuan University, Phitsanulok 65000, Thailand
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Serge Urbach
- Functional Proteomics Platform (FPP), IGF, Université Montpellier, CNRS, INSERM, Montpellier, France
| | - Kazufumi Mochizuki
- Epigenetic Chromatin Regulation team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - François Juge
- Tubulin Code team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
| | - Krzysztof Rogowski
- Tubulin Code team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
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3
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Cole ES, Maier W, Joachimiak E, Jiang YY, Lee C, Collet E, Chmelik C, Romero DP, Chalker D, Alli NK, Ruedlin TM, Ozzello C, Gaertig J. The Tetrahymena bcd1 mutant implicates endosome trafficking in ciliate, cortical pattern formation. Mol Biol Cell 2023; 34:ar82. [PMID: 37163326 PMCID: PMC10398878 DOI: 10.1091/mbc.e22-11-0501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/15/2023] [Accepted: 05/01/2023] [Indexed: 05/11/2023] Open
Abstract
Ciliates, such as Tetrahymena thermophila, evolved complex mechanisms to determine both the location and dimensions of cortical organelles such as the oral apparatus (OA: involved in phagocytosis), cytoproct (Cyp: for eliminating wastes), and contractile vacuole pores (CVPs: involved in water expulsion). Mutations have been recovered in Tetrahymena that affect both the localization of such organelles along anterior-posterior and circumferential body axes and their dimensions. Here we describe BCD1, a ciliate pattern gene that encodes a conserved Beige-BEACH domain-containing protein a with possible protein kinase A (PKA)-anchoring activity. Similar proteins have been implicated in endosome trafficking and are linked to human Chediak-Higashi syndrome and autism. Mutations in the BCD1 gene broaden cortical organelle domains as they assemble during predivision development. The Bcd1 protein localizes to membrane pockets at the base of every cilium that are active in endocytosis. PKA activity has been shown to promote endocytosis in other organisms, so we blocked clathrin-mediated endocytosis (using "dynasore") and inhibited PKA (using H89). In both cases, treatment produced partial phenocopies of the bcd1 pattern mutant. This study supports a model in which the dimensions of diverse cortical organelle assembly-platforms may be determined by regulated balance between constitutive exocytic delivery and PKA-regulated endocytic retrieval of organelle materials and determinants.
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Affiliation(s)
- Eric S. Cole
- Biology Department, St. Olaf College, Northfield, MN 55057
| | - Wolfgang Maier
- Bioinformatics Group, Department of Computer Science, University of Freiburg, 79110 Freiburg, Germany
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Yu-yang Jiang
- Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637
| | - Chinkyu Lee
- Department of Cellular Biology, University of Georgia, Athens, GA 30605
| | - Erik Collet
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Carl Chmelik
- Biology Department, St. Olaf College, Northfield, MN 55057
| | - Daniel P. Romero
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455
| | - Douglas Chalker
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63021
| | - Nurudeen K. Alli
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63021
| | - Tina M. Ruedlin
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63021
| | - Courtney Ozzello
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA 30605
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4
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Tian M, Cai X, Liu Y, Liucong M, Howard-Till R. A practical reference for studying meiosis in the model ciliate Tetrahymena thermophila. MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:595-608. [PMID: 37078080 PMCID: PMC10077211 DOI: 10.1007/s42995-022-00149-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 09/28/2022] [Indexed: 05/03/2023]
Abstract
Meiosis is a critical cell division program that produces haploid gametes for sexual reproduction. Abnormalities in meiosis are often causes of infertility and birth defects (e.g., Down syndrome). Most organisms use a highly specialized zipper-like protein complex, the synaptonemal complex (SC), to guide and stabilize pairing of homologous chromosomes in meiosis. Although the SC is critical for meiosis in many eukaryotes, there are organisms that perform meiosis without a functional SC. However, such SC-less meiosis is poorly characterized. To understand the features of SC-less meiosis and its adaptive significance, the ciliated protozoan Tetrahymena was selected as a model. Meiosis research in Tetrahymena has revealed intriguing aspects of the regulatory programs utilized in its SC-less meiosis, yet additional efforts are needed for obtaining an in-depth comprehension of mechanisms that are associated with the absence of SC. Here, aiming at promoting a wider application of Tetrahymena for meiosis research, we introduce basic concepts and core techniques for studying meiosis in Tetrahymena and then suggest future directions for expanding the current Tetrahymena meiosis research toolbox. These methodologies could be adopted for dissecting meiosis in poorly characterized ciliates that might reveal novel features. Such data will hopefully provide insights into the function of the SC and the evolution of meiosis from a unique perspective. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00149-8.
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Affiliation(s)
- Miao Tian
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
- Institute of Human Genetics, CNRS, University of Montpellier, 34090 Montpellier, France
| | - Xia Cai
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Yujie Liu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Mingmei Liucong
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Rachel Howard-Till
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA USA
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5
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Sanchez Granel ML, Siburu NG, Fricska A, Maldonado LL, Gargiulo LB, Nudel CB, Uttaro AD, Nusblat AD. A novel Tetrahymena thermophila sterol C-22 desaturase belongs to the Fatty Acid Hydroxylase/Desaturase superfamily. J Biol Chem 2022; 298:102397. [PMID: 35988640 PMCID: PMC9485055 DOI: 10.1016/j.jbc.2022.102397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/09/2022] [Accepted: 08/15/2022] [Indexed: 11/27/2022] Open
Abstract
Sterols in eukaryotic cells play important roles in modulating membrane fluidity and in cell signaling and trafficking. During evolution, a combination of gene losses and acquisitions gave rise to an extraordinary diversity of sterols in different organisms. The sterol C-22 desaturase identified in plants and fungi as a cytochrome P-450 monooxygenase evolved from the first eukaryotic cytochrome P450 and was lost in many lineages. Although the ciliate Tetrahymena thermophila desaturates sterols at the C-22 position, no cytochrome P-450 orthologs are present in the genome. Here, we aim to identify the genes responsible for the desaturation as well as their probable origin. We used gene knockout and yeast heterologous expression approaches to identify two putative genes, retrieved from a previous transcriptomic analysis, as sterol C-22 desaturases. Furthermore, we demonstrate using bioinformatics and evolutionary analyses that both genes encode a novel type of sterol C-22 desaturase that belongs to the large fatty acid hydroxylase/desaturase superfamily and the genes originated by genetic duplication prior to functional diversification. These results stress the widespread existence of nonhomologous isofunctional enzymes among different lineages of the tree of life as well as the suitability for the use of T. thermophila as a valuable model to investigate the evolutionary process of large enzyme families.
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Affiliation(s)
- María L Sanchez Granel
- Instituto de Nanobiotecnología (NANOBIOTEC), CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina
| | - Nicolás G Siburu
- Instituto de Biología Molecular y Celular de Rosario, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda s/n, S2000FHQ, Rosario, Argentina
| | - Annamária Fricska
- Instituto de Nanobiotecnología (NANOBIOTEC), CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina
| | - Lucas L Maldonado
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), CONICET, Facultad de Medicina, Universidad de Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina
| | - Laura B Gargiulo
- Instituto de Nanobiotecnología (NANOBIOTEC), CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina
| | - Clara B Nudel
- Instituto de Nanobiotecnología (NANOBIOTEC), CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina
| | - Antonio D Uttaro
- Instituto de Biología Molecular y Celular de Rosario, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda s/n, S2000FHQ, Rosario, Argentina.
| | - Alejandro D Nusblat
- Instituto de Nanobiotecnología (NANOBIOTEC), CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina.
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6
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Zhang J, Tian M, Chen K, Yan G, Xiong J, Miao W. Zfp1, a Cys2His2 zinc finger protein is required for meiosis initiation in Tetrahymena thermophila. Cell Cycle 2022; 21:1422-1433. [PMID: 35293272 PMCID: PMC9345619 DOI: 10.1080/15384101.2022.2053449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Meiosis is an important and highly conserved process that occurs during eukaryotic sexual reproduction. Diverse mechanisms are responsible for meiosis initiation among eukaryotes, and transcription factors have been established to have an important role in many species. However, the specific function of transcription factors in initiating meiosis in ciliates is unknown. Here we show that a putative Cys2His2 zinc finger-containing transcription factor encoded by the ZFP1 gene is specifically expressed during sexual reproduction in Tetrahymena thermophila. Meiosis is not initiated in the cells lacking ZFP1. Transcriptome sequencing analyses reveal that Zfp1 is required for the expression of many meiosis-specific genes. Our results indicate that Zfp1 could be a transcriptional activator required for meiosis initiation in T. thermophila.
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Affiliation(s)
- Jing Zhang
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Miao Tian
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Kai Chen
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Guanxiong Yan
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China.,College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, Shanghai, China
| | - Jie Xiong
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Wei Miao
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China.,State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China.,CAS Center for Excellence in Animal Evolution and Genetics, Kunming, Yunnan, China
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7
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Tian M, Mochizuki K, Loidl J. Arrested crossover precursor structures form stable homologous bonds in a Tetrahymena meiotic mutant. PLoS One 2022; 17:e0263691. [PMID: 35171923 PMCID: PMC8849441 DOI: 10.1371/journal.pone.0263691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/24/2022] [Indexed: 11/18/2022] Open
Abstract
Meiotic DNA double-strand breaks produce reciprocally exchanged DNA strands, which mature into chiasmata that hold homologous chromosomes together as bivalents. These bivalents are subsequently separated in the first meiotic division. In a mutant lacking the newly identified Tetrahymena gene APRO1 (Anaphase promoting 1), meiosis is arrested by the end of prophase. Mature chiasmata are not formed but bivalents are connected via a molecular precursor structure. In-depth analysis of this arrested intermediate structure may help to elucidate the noncanonical molecular recombination pathway in Tetrahymena.
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Affiliation(s)
- Miao Tian
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | | | - Josef Loidl
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
- * E-mail:
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8
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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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9
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Abstract
Piwi-bound small RNAs induce programmed DNA elimination in the ciliated protozoan Tetrahymena. Using the phenomenon called codeletion, this process can be reprogrammed to induce ectopic DNA elimination at basically any given genomic location. Here, we describe the usage of codeletion for genetic studies in Tetrahymena and for investigations of the molecular mechanism of Piwi-directed programmed DNA elimination.
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Affiliation(s)
- Salman Shehzada
- Institute of Human Genetics (IGH), CNRS and University of Montpellier, Montpellier, France
| | - Kazufumi Mochizuki
- Institute of Human Genetics (IGH), CNRS and University of Montpellier, Montpellier, France.
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10
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Composition and function of the C1b/C1f region in the ciliary central apparatus. Sci Rep 2021; 11:11760. [PMID: 34083607 PMCID: PMC8175508 DOI: 10.1038/s41598-021-90996-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/19/2021] [Indexed: 02/04/2023] Open
Abstract
Motile cilia are ultrastructurally complex cell organelles with the ability to actively move. The highly conserved central apparatus of motile 9 × 2 + 2 cilia is composed of two microtubules and several large microtubule-bound projections, including the C1b/C1f supercomplex. The composition and function of C1b/C1f subunits has only recently started to emerge. We show that in the model ciliate Tetrahymena thermophila, C1b/C1f contains several evolutionarily conserved proteins: Spef2A, Cfap69, Cfap246/LRGUK, Adgb/androglobin, and a ciliate-specific protein Tt170/TTHERM_00205170. Deletion of genes encoding either Spef2A or Cfap69 led to a loss of the entire C1b projection and resulted in an abnormal vortex motion of cilia. Loss of either Cfap246 or Adgb caused only minor alterations in ciliary motility. Comparative analyses of wild-type and C1b-deficient mutant ciliomes revealed that the levels of subunits forming the adjacent C2b projection but not C1d projection are greatly reduced, indicating that C1b stabilizes C2b. Moreover, the levels of several IFT and BBS proteins, HSP70, and enzymes that catalyze the final steps of the glycolytic pathway: enolase ENO1 and pyruvate kinase PYK1, are also reduced in the C1b-less mutants.
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11
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Bazan R, Schröfel A, Joachimiak E, Poprzeczko M, Pigino G, Wloga D. Ccdc113/Ccdc96 complex, a novel regulator of ciliary beating that connects radial spoke 3 to dynein g and the nexin link. PLoS Genet 2021; 17:e1009388. [PMID: 33661892 PMCID: PMC7987202 DOI: 10.1371/journal.pgen.1009388] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 03/23/2021] [Accepted: 01/28/2021] [Indexed: 11/19/2022] Open
Abstract
Ciliary beating requires the coordinated activity of numerous axonemal complexes. The protein composition and role of radial spokes (RS), nexin links (N-DRC) and dyneins (ODAs and IDAs) is well established. However, how information is transmitted from the central apparatus to the RS and across other ciliary structures remains unclear. Here, we identify a complex comprising the evolutionarily conserved proteins Ccdc96 and Ccdc113, positioned parallel to N-DRC and forming a connection between RS3, dynein g, and N-DRC. Although Ccdc96 and Ccdc113 can be transported to cilia independently, their stable docking and function requires the presence of both proteins. Deletion of either CCDC113 or CCDC96 alters cilia beating frequency, amplitude and waveform. We propose that the Ccdc113/Ccdc96 complex transmits signals from RS3 and N-DRC to dynein g and thus regulates its activity and the ciliary beat pattern.
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Affiliation(s)
- Rafał Bazan
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Adam Schröfel
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Martyna Poprzeczko
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Human Technopole, Milan, Italy
- * E-mail: (GP); (DW)
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
- * E-mail: (GP); (DW)
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12
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Tian M, Agreiter C, Loidl J. Spatial constraints on chromosomes are instrumental to meiotic pairing. J Cell Sci 2020; 133:jcs253724. [PMID: 33172984 PMCID: PMC7725606 DOI: 10.1242/jcs.253724] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/29/2020] [Indexed: 01/10/2023] Open
Abstract
In most eukaryotes, the meiotic chromosomal bouquet (comprising clustered chromosome ends) provides an ordered chromosome arrangement that facilitates pairing and recombination between homologous chromosomes. In the protist Tetrahymena thermophila, the meiotic prophase nucleus stretches enormously, and chromosomes assume a bouquet-like arrangement in which telomeres and centromeres are attached to opposite poles of the nucleus. We have identified and characterized three meiosis-specific genes [meiotic nuclear elongation 1-3 (MELG1-3)] that control nuclear elongation, and centromere and telomere clustering. The Melg proteins interact with cytoskeletal and telomere-associated proteins, and probably repurpose them for reorganizing the meiotic prophase nucleus. A lack of sequence similarity between the Tetrahymena proteins responsible for telomere clustering and bouquet proteins of other organisms suggests that the Tetrahymena bouquet is analogous, rather than homologous, to the conserved eukaryotic bouquet. We also report that centromere clustering is more important than telomere clustering for homologous pairing. Therefore, we speculate that centromere clustering may have been the primordial mechanism for chromosome pairing in early eukaryotes.
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Affiliation(s)
- Miao Tian
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Christiane Agreiter
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
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13
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Soh AWJ, van Dam TJP, Stemm-Wolf AJ, Pham AT, Morgan GP, O'Toole ET, Pearson CG. Ciliary force-responsive striated fibers promote basal body connections and cortical interactions. J Cell Biol 2020; 219:jcb.201904091. [PMID: 31740506 PMCID: PMC7039215 DOI: 10.1083/jcb.201904091] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 07/15/2019] [Accepted: 10/02/2019] [Indexed: 12/28/2022] Open
Abstract
Multi-ciliary arrays promote fluid flow and cellular motility using the polarized and coordinated beating of hundreds of motile cilia. Tetrahymena basal bodies (BBs) nucleate and position cilia, whereby BB-associated striated fibers (SFs) promote BB anchorage and orientation into ciliary rows. Mutants that shorten SFs cause disoriented BBs. In contrast to the cytotaxis model, we show that disoriented BBs with short SFs can regain normal orientation if SF length is restored. In addition, SFs adopt unique lengths by their shrinkage and growth to establish and maintain BB connections and cortical interactions in a ciliary force-dependent mechanism. Tetrahymena SFs comprise at least eight uniquely localizing proteins belonging to the SF-assemblin family. Loss of different proteins that localize to the SF base disrupts either SF steady-state length or ciliary force-induced SF elongation. Thus, the dynamic regulation of SFs promotes BB connections and cortical interactions to organize ciliary arrays.
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Affiliation(s)
- Adam W J Soh
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO
| | - Teunis J P van Dam
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, Netherlands
| | - Alexander J Stemm-Wolf
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO
| | - Andrew T Pham
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO
| | - Garry P Morgan
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO
| | - Eileen T O'Toole
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO
| | - Chad G Pearson
- Anschutz Medical Campus, Department of Cell and Developmental Biology, University of Colorado, Aurora, CO
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14
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Akematsu T, Sánchez-Fernández R, Kosta F, Holzer E, Loidl J. The Transmembrane Protein Semi1 Positions Gamete Nuclei for Reciprocal Fertilization in Tetrahymena. iScience 2019; 23:100749. [PMID: 31884169 PMCID: PMC6941865 DOI: 10.1016/j.isci.2019.100749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/01/2019] [Accepted: 11/25/2019] [Indexed: 11/01/2022] Open
Abstract
During sexual reproduction in the ciliate, Tetrahymena thermophila, cells of complementary mating type pair ("conjugate") undergo simultaneous meiosis and fertilize each other. In both mating partners only one of the four meiotic products is "selected" to escape autophagy, and this nucleus divides mitotically to produce two pronuclei. The migrating pronucleus of one cell translocates to the mating partner and fuses with its stationary pronucleus and vice versa. Selection of the designated gametic nucleus was thought to depend on its position within the cell because it always attaches to the junction with the partner cell. Here we show that a transmembrane protein, Semi1, is crucial for attachment. Loss of Semi1 causes failure to attach and consequent infertility. However, a nucleus is selected and gives rise to pronuclei regardless of Semi1 expression, indicating that attachment of a nucleus to the junction is not a precondition for selection but follows the selection process.
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Affiliation(s)
- Takahiko Akematsu
- Department of Chromosome Biology, University of Vienna, Dr. Bohr-Gasse 9, Vienna 1030, Austria.
| | | | - Felix Kosta
- Department of Chromosome Biology, University of Vienna, Dr. Bohr-Gasse 9, Vienna 1030, Austria
| | - Elisabeth Holzer
- Department of Chromosome Biology, University of Vienna, Dr. Bohr-Gasse 9, Vienna 1030, Austria
| | - Josef Loidl
- Department of Chromosome Biology, University of Vienna, Dr. Bohr-Gasse 9, Vienna 1030, Austria
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15
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Tian M, Loidl J. A chromatin-associated protein required for inducing and limiting meiotic DNA double-strand break formation. Nucleic Acids Res 2019; 46:11822-11834. [PMID: 30357385 PMCID: PMC6294514 DOI: 10.1093/nar/gky968] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/05/2018] [Indexed: 11/13/2022] Open
Abstract
Programmed DNA double-strand breaks (DSBs) are required for meiotic recombination, but the number is strictly controlled because they are potentially harmful. Here we report a novel protein, Pars11, which is required for Spo11-dependent DSB formation in the protist Tetrahymena. Pars11 localizes to chromatin early in meiotic prophase in a Spo11-independent manner and is removed before the end of prophase. Pars11 removal depends on DSB formation and ATR-dependent phosphorylation. In the absence of the DNA damage sensor kinase ATR, Pars11 is retained on chromatin and excess DSBs are generated. Similar levels of Pars11 persistence and DSB overproduction occur in a non-phosphorylatable pars11 mutant. We conclude that Pars11 supports DSB formation by Spo11 until enough DSBs are formed; thereafter, DSB production stops in response to ATR-dependent degradation of Pars11 or its removal from chromatin. A similar DSB control mechanism involving a Rec114-Tel1/ATM-dependent negative feedback loop regulates DSB formation in budding yeast. However, there is no detectable sequence homology between Pars11 and Rec114, and DSB numbers are more tightly controlled by Pars11 than by Rec114. The discovery of this mechanism for DSB regulation in the evolutionarily distant protist and fungal lineages suggests that it is conserved across eukaryotes.
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Affiliation(s)
- Miao Tian
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
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16
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Xu J, Li X, Song W, Wang W, Gao S. Cyclin Cyc2p is required for micronuclear bouquet formation in Tetrahymena thermophila. SCIENCE CHINA-LIFE SCIENCES 2019; 62:668-680. [PMID: 30820856 DOI: 10.1007/s11427-018-9369-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 11/19/2018] [Indexed: 01/31/2023]
Abstract
Meiotic bouquet formation (known as crescent formation in Tetrahymena thermophila) is indispensable for homologous pairing and recombination, but the regulatory mechanism of bouquet formation remains largely unknown. As a conjugation specific cyclin gene, CYC2 knockout mutants failed to form an elongated crescent structure and aborted meiosis progress in T. thermophila. γ-H2A.X staining revealed fewer micronuclear DNA double-strand breaks (DSBs) in cyc2Δ cells than in wild-type cells. Furthermore, cyc2Δ cells still failed to form a crescent structure even though DSBs were induced by exogenous agents, indicating that a lack of DSBs was not completely responsible for failure to enter the crescent stage. Tubulin staining showed that impaired perinuclear microtubule structure may contribute to the blockage in micronuclear elongation. At the same time, expression of microtubule-associated kinesin genes, KIN11 and KIN141, was significantly downregulated in cyc2Δ cells. Moreover, micronuclear specific accumulation of heterochromatin marker trimethylated H3K23 abnormally increased in the cyc2Δ mutants. Together, these results show that cyclin Cyc2p is required for micronuclear bouquet formation via controlling microtubule-directed nuclear elongation in Tetrahymena.
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Affiliation(s)
- Jing Xu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
- College of Life Science, Shanxi University, Taiyuan, 030006, China
- Key Laboratory of Chemical Biology and Molecular Engineering of the Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Xiaoxiong Li
- Key Laboratory of Chemical Biology and Molecular Engineering of the Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Weibo Song
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of the Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China.
| | - Shan Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China.
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
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17
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Urbanska P, Joachimiak E, Bazan R, Fu G, Poprzeczko M, Fabczak H, Nicastro D, Wloga D. Ciliary proteins Fap43 and Fap44 interact with each other and are essential for proper cilia and flagella beating. Cell Mol Life Sci 2018; 75:4479-4493. [PMID: 29687140 PMCID: PMC6208767 DOI: 10.1007/s00018-018-2819-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/13/2018] [Accepted: 04/13/2018] [Indexed: 11/08/2022]
Abstract
Cilia beating is powered by the inner and outer dynein arms (IDAs and ODAs). These multi-subunit macrocomplexes are arranged in two rows on each outer doublet along the entire cilium length, except its distal end. To generate cilia beating, the activity of ODAs and IDAs must be strictly regulated locally by interactions with the dynein arm-associated structures within each ciliary unit and coordinated globally in time and space between doublets and along the axoneme. Here, we provide evidence of a novel ciliary complex composed of two conserved WD-repeat proteins, Fap43p and Fap44p. This complex is adjacent to another WD-repeat protein, Fap57p, and most likely the two-headed inner dynein arm, IDA I1. Loss of either protein results in altered waveform, beat stroke and reduced swimming speed. The ciliary localization of Fap43p and Fap44p is interdependent in the ciliate Tetrahymena thermophila.
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Affiliation(s)
- Paulina Urbanska
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology PAS, Pasteur 3, 02-093, Warsaw, Poland
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology PAS, Pasteur 3, 02-093, Warsaw, Poland
| | - Rafał Bazan
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology PAS, Pasteur 3, 02-093, Warsaw, Poland
| | - Gang Fu
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, USA
| | - Martyna Poprzeczko
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology PAS, Pasteur 3, 02-093, Warsaw, Poland
| | - Hanna Fabczak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology PAS, Pasteur 3, 02-093, Warsaw, Poland
| | - Daniela Nicastro
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, USA
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology PAS, Pasteur 3, 02-093, Warsaw, Poland.
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18
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Ali EI, Loidl J, Howard-Till RA. A streamlined cohesin apparatus is sufficient for mitosis and meiosis in the protist Tetrahymena. Chromosoma 2018; 127:421-435. [PMID: 29948142 PMCID: PMC6208729 DOI: 10.1007/s00412-018-0673-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/18/2018] [Accepted: 05/28/2018] [Indexed: 02/03/2023]
Abstract
In order to understand its diverse functions, we have studied cohesin in the evolutionarily distant ciliate model organism Tetrahymena thermophila. In this binucleate cell, the heritable germline genome is maintained separately from the transcriptionally active somatic genome. In a previous study, we showed that a minimal cohesin complex in Tetrahymena consisted of homologs of Smc1, Smc3, and Rec8, which are present only in the germline nucleus, where they are needed for normal chromosome segregation as well as meiotic DNA repair. In this study, we confirm that a putative homolog of Scc3 is a member of this complex. In the absence of Scc3, Smc1 and Rec8 fail to localize to germline nuclei, Rec8 is hypo-phosphorylated, and cells show phenotypes similar to depletion of Smc1 and Rec8. We also identify a homolog of Scc2, which in other organisms is part of a heterodimeric complex (Scc2/Scc4) that helps load cohesin onto chromatin. In Tetrahymena, Scc2 interacts with Rec8 and Scc3, and its absence causes defects in mitotic and meiotic divisions. Scc2 is not required for chromosomal association of cohesin, but Rec8 is hypo-phosphorylated in its absence. Moreover, we did not identify a homolog of the cohesin loader Scc4, and no evidence was found of auxiliary factors, such as Eco1, Pds5, or WAPL. We propose that in Tetrahymena, a single, minimal cohesin complex performs all necessary functions for germline mitosis and meiosis, but is dispensable for transcription regulation and chromatin organization of the somatic genome.
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Affiliation(s)
- Emine I Ali
- Department of Chromosome Biology, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Rachel A Howard-Till
- Department of Chromosome Biology, Vienna Biocenter, University of Vienna, Vienna, Austria.
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19
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Affiliation(s)
- María E. Elguero
- Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Clara B. Nudel
- Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alejandro D. Nusblat
- Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
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20
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Noto T, Mochizuki K. Whats, hows and whys of programmed DNA elimination in Tetrahymena. Open Biol 2018; 7:rsob.170172. [PMID: 29021213 PMCID: PMC5666084 DOI: 10.1098/rsob.170172] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/12/2017] [Indexed: 12/20/2022] Open
Abstract
Programmed genome rearrangements in ciliates provide fascinating examples of flexible epigenetic genome regulations and important insights into the interaction between transposable elements (TEs) and host genomes. DNA elimination in Tetrahymena thermophila removes approximately 12 000 internal eliminated sequences (IESs), which correspond to one-third of the genome, when the somatic macronucleus (MAC) differentiates from the germline micronucleus (MIC). More than half of the IESs, many of which show high similarity to TEs, are targeted for elimination in cis by the small RNA-mediated genome comparison of the MIC to the MAC. Other IESs are targeted for elimination in trans by the same small RNAs through repetitive sequences. Furthermore, the small RNA–heterochromatin feedback loop ensures robust DNA elimination. Here, we review an updated picture of the DNA elimination mechanism, discuss the physiological and evolutionary roles of DNA elimination, and outline the key questions that remain unanswered.
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Affiliation(s)
- Tomoko Noto
- Institute of Human Genetics, UMR 9002, CNRS and University of Montpellier, Montpellier, France
| | - Kazufumi Mochizuki
- Institute of Human Genetics, UMR 9002, CNRS and University of Montpellier, Montpellier, France
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21
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Noto T, Mochizuki K. Small RNA-Mediated trans-Nuclear and trans-Element Communications in Tetrahymena DNA Elimination. Curr Biol 2018; 28:1938-1949.e5. [DOI: 10.1016/j.cub.2018.04.071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/17/2018] [Accepted: 04/19/2018] [Indexed: 10/14/2022]
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22
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Akematsu T, Fukuda Y, Garg J, Fillingham JS, Pearlman RE, Loidl J. Post-meiotic DNA double-strand breaks occur in Tetrahymena, and require Topoisomerase II and Spo11. eLife 2017. [PMID: 28621664 PMCID: PMC5482572 DOI: 10.7554/elife.26176] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Based on observations of markers for DNA lesions, such as phosphorylated histone H2AX (γH2AX) and open DNA ends, it has been suggested that post-meiotic DNA double-strand breaks (PM-DSBs) enable chromatin remodeling during animal spermiogenesis. However, the existence of PM-DSBs is unconfirmed, and the mechanism responsible for their formation is unclear. Here, we report the first direct observation of programmed PM-DSBs via the electrophoretic separation of DSB-generated DNA fragments in the ciliate Tetrahymena thermophila. These PM-DSBs are accompanied by switching from a heterochromatic to euchromatic chromatin structure in the haploid pronucleus. Both a topoisomerase II paralog with exclusive pronuclear expression and Spo11 are prerequisites for PM-DSB induction. Reduced PM-DSB induction blocks euchromatin formation, characterized by histone H3K56 acetylation, leading to a failure in gametic nuclei production. We propose that PM-DSBs are responsible for histone replacement during the reprogramming of generative to undifferentiated progeny nuclei. DOI:http://dx.doi.org/10.7554/eLife.26176.001
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Affiliation(s)
- Takahiko Akematsu
- Department of Chromosome Biology, University of Vienna, Vienna, Austria
| | - Yasuhiro Fukuda
- Department of Biodiversity Science, Tohoku University, Oosaki, Japan.,Division of Biological Resource Science, Tohoku University, Oosaki, Japan.,Graduate School of Agricultural Science, Tohoku University, Oosaki, Japan
| | - Jyoti Garg
- Department of Biology, York University, Toronto, Canada
| | | | | | - Josef Loidl
- Department of Chromosome Biology, University of Vienna, Vienna, Austria
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23
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Tetrahymena as a Unicellular Model Eukaryote: Genetic and Genomic Tools. Genetics 2017; 203:649-65. [PMID: 27270699 DOI: 10.1534/genetics.114.169748] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 04/08/2016] [Indexed: 12/12/2022] Open
Abstract
Tetrahymena thermophila is a ciliate model organism whose study has led to important discoveries and insights into both conserved and divergent biological processes. In this review, we describe the tools for the use of Tetrahymena as a model eukaryote, including an overview of its life cycle, orientation to its evolutionary roots, and methodological approaches to forward and reverse genetics. Recent genomic tools have expanded Tetrahymena's utility as a genetic model system. With the unique advantages that Tetrahymena provide, we argue that it will continue to be a model organism of choice.
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24
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Shodhan A, Kataoka K, Mochizuki K, Novatchkova M, Loidl J. A Zip3-like protein plays a role in crossover formation in the SC-less meiosis of the protist Tetrahymena. Mol Biol Cell 2017; 28:825-833. [PMID: 28100637 PMCID: PMC5349789 DOI: 10.1091/mbc.e16-09-0678] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/21/2016] [Accepted: 01/09/2017] [Indexed: 11/11/2022] Open
Abstract
When programmed meiotic DNA double-strand breaks (DSBs) undergo recombinational repair, genetic crossovers (COs) may be formed. A certain level of this is required for the faithful segregation of chromosomes, but the majority of DSBs are processed toward a safer alternative, namely noncrossovers (NCOs), via nonreciprocal DNA exchange. At the crossroads between these two DSB fates is the Msh4-Msh5 (MutSγ) complex, which stabilizes CO-destined recombination intermediates and members of the Zip3/RNF212 family of RING finger proteins, which in turn stabilize MutSγ. These proteins function in the context of the synaptonemal complex (SC) and mainly act on SC-dependent COs. Here we show that in the SC-less ciliate Tetrahymena, Zhp3 (a protein distantly related to Zip3/RNF212), together with MutSγ, is responsible for the majority of COs. This activity of Zhp3 suggests an evolutionarily conserved SC-independent strategy for balancing CO:NCO ratios. Moreover, we report a novel meiosis-specific protein, Sa15, as an interacting partner of Zhp3. Sa15 forms linear structures in meiotic prophase nuclei to which Zhp3 localizes. Sa15 is required for a wild-type level of CO formation. Its linear organization suggests the existence of an underlying chromosomal axis that serves as a scaffold for Zhp3 and other recombination proteins.
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Affiliation(s)
- Anura Shodhan
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
| | - Kensuke Kataoka
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences and
| | - Kazufumi Mochizuki
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences and
| | - Maria Novatchkova
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences and
- Research Institute of Molecular Pathology, 1030 Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
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25
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The key role of CYC2 during meiosis in Tetrahymena thermophila. Protein Cell 2016; 7:236-249. [PMID: 27008457 PMCID: PMC4818844 DOI: 10.1007/s13238-016-0254-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/12/2016] [Indexed: 01/30/2023] Open
Abstract
Meiotic recombination is carried out through a specialized pathway for the formation and repair of DNA double-strand breaks (DSBs) made by the Spo11 protein. The present study shed light on the functional role of cyclin, CYC2, in Tetrahymena thermophila which has transcriptionally high expression level during meiosis process. Knocking out the CYC2 gene results in arrest of meiotic conjugation process at 2.5–3.5 h after conjugation initiation, before the meiosis division starts, and in company with the absence of DSBs. To investigate the underlying mechanism of this phenomenon, a complete transcriptome profile was performed between wild-type strain and CYC2 knock-out strain. Functional analysis of RNA-Seq results identifies related differentially expressed genes (DEGs) including SPO11 and these DEGs are enriched in DNA repair/mismatch repair (MMR) terms in homologous recombination (HR), which indicates that CYC2 could play a crucial role in meiosis by regulating SPO11 and participating in HR.
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