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Xiong W, Wei W, He M, Hu B, Men J, Tu J, Miao W. Construction of Tetrahymena strains with highly active arsenic methyltransferase genes for arsenic detoxification in aquatic environments. Ecotoxicol Environ Saf 2024; 275:116258. [PMID: 38547732 DOI: 10.1016/j.ecoenv.2024.116258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/26/2024] [Accepted: 03/22/2024] [Indexed: 04/12/2024]
Abstract
Biomethylation is an effective means of arsenic detoxification by organisms living in aquatic environments. Ciliated protozoa (including Tetrahymena species) play an important role in the biochemical cycles of aquatic ecosystems and have a potential application in arsenic biotransformation. This study compared arsenic tolerance, accumulation, methylation, and efflux in 11 Tetrahymena species. Nineteen arsenite (As(III)) S-adenosylmethionine (SAM) methyltransferase (arsM) genes, of which 12 are new discoveries, were identified, and protein sequences were studied. We then constructed recombinant cell lines based on the Tetrahymena thermophila (T. thermophila) wild-type SB210 strain and expressed each of the 19 arsM genes under the control of the metal-responsive the MTT1 promoter. In the presence of Cd2+ and As(V), expression of the arsM genes in the recombinant cell lines was much higher than in the donor species. Evaluation of the recombinant cell line identified one with ultra-high arsenic methylation enzyme activity, significantly higher arsenic methylation capacity and much faster methylation rate than other reported arsenic methylated organisms, which methylated 89% of arsenic within 6.5 h. It also had an excellent capacity for the arsenic detoxification of lake water containing As(V), 56% of arsenic was methylated at 250 μg/L As(V) in 48 h. This study has made a significant contribution to our knowledge on arsenic metabolism in protozoa and demonstrates the great potential to use Tetrahymena species in the arsenic biotransformation of aquatic environments.
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Affiliation(s)
- Wenjun Xiong
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Wei
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Man He
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Bin Hu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Jun Men
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Jiawei Tu
- School of Resource and Environmental Science, Wuhan University, Wuhan 430072, China.
| | - Wei Miao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key laboratory of Lake and Watershed Science for Water Security, Chinese Academy of Sciences, Nanjing 210008, China.
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Iwaï H, Beyer HM, Johansson JEM, Li M, Wlodawer A. The three-dimensional structure of the Vint domain from Tetrahymena thermophila suggests a ligand-regulated cleavage mechanism by the HINT fold. FEBS Lett 2024; 598:864-874. [PMID: 38351630 DOI: 10.1002/1873-3468.14817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 12/13/2023] [Accepted: 01/03/2024] [Indexed: 04/23/2024]
Abstract
Vint proteins have been identified in unicellular metazoans as a novel hedgehog-related gene family, merging the von Willebrand factor type A domain and the Hedgehog/INTein (HINT) domains. We present the first three-dimensional structure of the Vint domain from Tetrahymena thermophila corresponding to the auto-processing domain of hedgehog proteins, shedding light on the unique features, including an adduct recognition region (ARR). Our results suggest a potential binding between the ARR and sulfated glycosaminoglycans like heparin sulfate. Moreover, we uncover a possible regulatory role of the ARR in the auto-processing by Vint domains, expanding our understanding of the HINT domain evolution and their use in biotechnological applications. Vint domains might have played a crucial role in the transition from unicellular to multicellular organisms.
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Affiliation(s)
- Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, Finland
| | - Hannes M Beyer
- Institute of Biotechnology, University of Helsinki, Finland
| | | | - Mi Li
- Center for Structural Biology, National Cancer Institute, Frederick, MD, USA
- Basic Science Program, Frederick National Laboratory for Cancer Research, MD, USA
| | - Alexander Wlodawer
- Center for Structural Biology, National Cancer Institute, Frederick, MD, USA
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Wang L, Yang S, Xue Y, Bo T, Xu J, Wang W. Mismatch Repair Protein Msh6 Tt Is Necessary for Nuclear Division and Gametogenesis in Tetrahymena thermophila. Int J Mol Sci 2023; 24:17619. [PMID: 38139447 PMCID: PMC10743813 DOI: 10.3390/ijms242417619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/15/2023] [Accepted: 12/16/2023] [Indexed: 12/24/2023] Open
Abstract
DNA mismatch repair (MMR) improves replication accuracy by up to three orders of magnitude. The MutS protein in E. coli or its eukaryotic homolog, the MutSα (Msh2-Msh6) complex, recognizes base mismatches and initiates the mismatch repair mechanism. Msh6 is an essential protein for assembling the heterodimeric complex. However, the function of the Msh6 subunit remains elusive. Tetrahymena undergoes multiple DNA replication and nuclear division processes, including mitosis, amitosis, and meiosis. Here, we found that Msh6Tt localized in the macronucleus (MAC) and the micronucleus (MIC) during the vegetative growth stage and starvation. During the conjugation stage, Msh6Tt only localized in MICs and newly developing MACs. MSH6Tt knockout led to aberrant nuclear division during vegetative growth. The MSH6TtKO mutants were resistant to treatment with the DNA alkylating agent methyl methanesulfonate (MMS) compared to wild type cells. MSH6Tt knockout affected micronuclear meiosis and gametogenesis during the conjugation stage. Furthermore, Msh6Tt interacted with Msh2Tt and MMR-independent factors. Downregulation of MSH2Tt expression affected the stability of Msh6Tt. In addition, MSH6Tt knockout led to the upregulated expression of several MSH6Tt homologs at different developmental stages. Msh6Tt is involved in macronuclear amitosis, micronuclear mitosis, micronuclear meiosis, and gametogenesis in Tetrahymena.
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Affiliation(s)
- Lin Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (L.W.); (S.Y.); (Y.X.); (T.B.)
| | - Sitong Yang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (L.W.); (S.Y.); (Y.X.); (T.B.)
| | - Yuhuan Xue
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (L.W.); (S.Y.); (Y.X.); (T.B.)
| | - Tao Bo
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (L.W.); (S.Y.); (Y.X.); (T.B.)
- Shanxi Key Laboratory of Biotechnology, Taiyuan 030006, China
| | - Jing Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (L.W.); (S.Y.); (Y.X.); (T.B.)
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (L.W.); (S.Y.); (Y.X.); (T.B.)
- Shanxi Key Laboratory of Biotechnology, Taiyuan 030006, China
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Hao H, Ren C, Lian Y, Zhao M, Bo T, Xu J, Wang W. Independent and Complementary Functions of Caf1b and Hir1 for Chromatin Assembly in Tetrahymena thermophila. Cells 2023; 12:2828. [PMID: 38132148 PMCID: PMC10741905 DOI: 10.3390/cells12242828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/09/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023] Open
Abstract
Histones and DNA associate to form the nucleosomes of eukaryotic chromatin. Chromatin assembly factor 1 (CAF-1) complex and histone regulatory protein A (HIRA) complex mediate replication-couple (RC) and replication-independent (RI) nucleosome assembly, respectively. CHAF1B and HIRA share a similar domain but play different roles in nucleosome assembly by binding to the different interactors. At present, there is limited understanding for the similarities and differences in their respective functions. Tetrahymena thermophila contains transcriptionally active polyploid macronuclei (MAC) and transcriptionally silent diploid micronuclei (MIC). Here, the distribution patterns of Caf1b and Hir1 exhibited both similarities and distinctions. Both proteins localized to the MAC and MIC during growth, and to the MIC during conjugation. However, Hir1 exhibited additional signaling on parental MAC and new MAC during sexual reproduction and displayed a punctate signal on developing anlagen. Caf1b and Hir1 only co-localized in the MIC with Pcna1 during conjugation. Knockdown of CAF1B impeded cellular growth and arrested sexual reproductive development. Loss of HIR1 led to MIC chromosome defects and aborted sexual development. Co-interference of CAF1B and HIR1 led to a more severe phenotype. Moreover, CAF1B knockdown led to the up-regulation of HIR1 expression, while knockdown of HIR1 also led to an increase in CAF1B expression. Furthermore, Caf1b and Hir1 interacted with different interactors. These results showed that CAF-1 and Hir1 have independent and complementary functions for chromatin assembly in T. thermophila.
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Affiliation(s)
- Huijuan Hao
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (H.H.); (C.R.); (Y.L.); (M.Z.); (T.B.)
| | - Chenhui Ren
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (H.H.); (C.R.); (Y.L.); (M.Z.); (T.B.)
| | - Yinjie Lian
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (H.H.); (C.R.); (Y.L.); (M.Z.); (T.B.)
| | - Min Zhao
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (H.H.); (C.R.); (Y.L.); (M.Z.); (T.B.)
| | - Tao Bo
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (H.H.); (C.R.); (Y.L.); (M.Z.); (T.B.)
| | - Jing Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (H.H.); (C.R.); (Y.L.); (M.Z.); (T.B.)
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China; (H.H.); (C.R.); (Y.L.); (M.Z.); (T.B.)
- Shanxi Key Laboratory of Biotechnology, Taiyuan 030006, China
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Legal T, Parra M, Tong M, Black CS, Joachimiak E, Valente-Paterno M, Lechtreck K, Gaertig J, Bui KH. CEP104/FAP256 and associated cap complex maintain stability of the ciliary tip. J Cell Biol 2023; 222:e202301129. [PMID: 37756660 PMCID: PMC10522465 DOI: 10.1083/jcb.202301129] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/13/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023] Open
Abstract
Cilia are essential organelles that protrude from the cell body. Cilia are made of a microtubule-based structure called the axoneme. In most types of cilia, the ciliary tip is distinct from the rest of the cilium. Here, we used cryo-electron tomography and subtomogram averaging to obtain the structure of the ciliary tip of the ciliate Tetrahymena thermophila. We show that the microtubules at the tip are highly crosslinked with each other and stabilized by luminal proteins, plugs, and cap proteins at the plus ends. In the tip region, the central pair lacks typical projections and twists significantly. By analyzing cells lacking a ciliary tip-enriched protein CEP104/FAP256 by cryo-electron tomography and proteomics, we discovered candidates for the central pair cap complex and explained the potential functions of CEP104/FAP256. These data provide new insights into the function of the ciliary tip and the mechanisms of ciliary assembly and length regulation.
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Affiliation(s)
- Thibault Legal
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Mireya Parra
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Maxwell Tong
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Corbin S. Black
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Melissa Valente-Paterno
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
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Üstüntanır Dede AF, Arslanyolu M. Recombinant production of hormonally active human insulin from pre-proinsulin by Tetrahymena thermophila. Enzyme Microb Technol 2023; 170:110303. [PMID: 37562115 DOI: 10.1016/j.enzmictec.2023.110303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/12/2023]
Abstract
Alternative cell factories, such as the unicellular ciliate eukaryotic Tetrahymena thermophila, may be required for the production of protein therapeutics that are challenging to produce in conventional expression systems. T. thermophila (Tt) can secrete proteins with the post-translational modifications necessary for their function in humans. In this study, we tested if T. thermophila could process the human pre-proinsulin to produce hormonally active human insulin (hINS) with correct modifications. Flask and bioreactor culture of T. thermophila were used to produce the recombinant Tt-hINS either with or without an affinity tag from a codon-adapted pre-proinsulin sequence. Our results indicate that T. thermophila can produce a 6 kDa Tt-hINS monomer with the appropriate disulfide bonds after removal of the human insulin signal sequence or endogenous phospholipase A signal sequence, and the C-peptide of the human insulin. Additionally, Tt-hINS can form 12 kDa dimeric, 24 kDa tetrameric, and 36 kDa hexameric complexes. Tt-hINS-sfGFP fusion protein was localized to the vesicles within the cytoplasm and was secreted extracellularly. Assessing the affinity-purified Tt-hINS activity using the in vivo T. thermophila extracellular glucose drop assay, we observed that Tt-hINS induced a significant reduction (approximately 21 %) in extracellular glucose levels, indicative of its functional insulin activity. Our results demonstrate that T. thermophila is a promising candidate for the pharmaceutical and biotechnology industries as a host organism for the production of human protein drugs.
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Affiliation(s)
- Ayça Fulya Üstüntanır Dede
- Department of Biology, Institute of Graduate Programs, Eskisehir Technical University, Yunus Emre Campus, Eskisehir 26470, Turkey,.
| | - Muhittin Arslanyolu
- Department of Biology, Faculty of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskisehir 26470, Turkey.
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Cui J, Zhang L, Zhang Z, Luo X, Liu Y, Li C, Huang W, Zou L, Yu X, Xiao F. A precise and efficient circular RNA synthesis system based on a ribozyme derived from Tetrahymena thermophila. Nucleic Acids Res 2023; 51:e78. [PMID: 37378451 PMCID: PMC10415121 DOI: 10.1093/nar/gkad554] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 05/17/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
Classic strategies for circular RNA (circRNA) preparation always introduce large numbers of linear transcripts or extra nucleotides to the circularized product. In this study, we aimed to develop an efficient system for circRNA preparation based on a self-splicing ribozyme derived from an optimized Tetrahymena thermophila group Ⅰ intron. The target RNA sequence was inserted downstream of the ribozyme and a complementary antisense region was added upstream of the ribozyme to assist cyclization. Then, we compared the circularization efficiency of ribozyme or flanking intronic complementary sequence (ICS)-mediated methods through the DNMT1, CDR1as, FOXO3, and HIPK3 genes and found that the efficiency of our system was remarkably higher than that of flanking ICS-mediated method. Consequently, the circularized products mediated by ribozyme are not introduced with additional nucleotides. Meanwhile, the overexpressed circFOXO3 maintained its biological functions in regulating cell proliferation, migration, and apoptosis. Finally, a ribozyme-based circular mRNA expression system was demonstrated with a split green fluorescent protein (GFP) using an optimized Coxsackievirus B3 (CVB3) internal ribosome entry site (IRES) sequence, and this system achieved successful translation of circularized mRNA. Therefore, this novel, convenient, and rapid engineering RNA circularization system can be applied for the functional study and large-scale preparation of circular RNA in the future.
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Affiliation(s)
- Jingyi Cui
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, PR China
- Graduate School of Peking Union Medical College, Beijing 100730, PR China
- Clinical Biobank, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, PR China
| | - Lanxin Zhang
- Clinical Biobank, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, PR China
| | - Zaifeng Zhang
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, PR China
- Graduate School of Peking Union Medical College, Beijing 100730, PR China
| | - Xuanmei Luo
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, PR China
| | - Ye Liu
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, PR China
| | - Chang Li
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, PR China
| | - Wei Huang
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, PR China
| | - Lihui Zou
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, PR China
| | - Xue Yu
- Department of Cardiology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, PR China
| | - Fei Xiao
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, PR China
- Graduate School of Peking Union Medical College, Beijing 100730, PR China
- Clinical Biobank, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, PR China
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Kubo S, Black CS, Joachimiak E, Yang SK, Legal T, Peri K, Khalifa AAZ, Ghanaeian A, McCafferty CL, Valente-Paterno M, De Bellis C, Huynh PM, Fan Z, Marcotte EM, Wloga D, Bui KH. Native doublet microtubules from Tetrahymena thermophila reveal the importance of outer junction proteins. Nat Commun 2023; 14:2168. [PMID: 37061538 PMCID: PMC10105768 DOI: 10.1038/s41467-023-37868-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 04/03/2023] [Indexed: 04/17/2023] Open
Abstract
Cilia are ubiquitous eukaryotic organelles responsible for cellular motility and sensory functions. The ciliary axoneme is a microtubule-based cytoskeleton consisting of two central singlets and nine outer doublet microtubules. Cryo-electron microscopy-based studies have revealed a complex network inside the lumen of both tubules composed of microtubule-inner proteins (MIPs). However, the functions of most MIPs remain unknown. Here, we present single-particle cryo-EM-based analyses of the Tetrahymena thermophila native doublet microtubule and identify 42 MIPs. These data shed light on the evolutionarily conserved and diversified roles of MIPs. In addition, we identified MIPs potentially responsible for the assembly and stability of the doublet outer junction. Knockout of the evolutionarily conserved outer junction component CFAP77 moderately diminishes Tetrahymena swimming speed and beat frequency, indicating the important role of CFAP77 and outer junction stability in cilia beating generation and/or regulation.
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Affiliation(s)
- Shintaroh Kubo
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Corbin S Black
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Shun Kai Yang
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Thibault Legal
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Katya Peri
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Ahmad Abdelzaher Zaki Khalifa
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Avrin Ghanaeian
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Caitlyn L McCafferty
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, 78712, USA
| | - Melissa Valente-Paterno
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Chelsea De Bellis
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Phuong M Huynh
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Zhe Fan
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, 78712, USA
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland.
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada.
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada.
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9
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Manan A, Roytrakul S, Charoenlappanit S, Poolpak T, Ounjai P, Kruatrachue M, Yang KM, Pokethitiyook P. Glyphosate metabolism in Tetrahymena thermophila: A shotgun proteomic analysis approach. Environ Toxicol 2023; 38:867-882. [PMID: 36602419 DOI: 10.1002/tox.23735] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 11/11/2022] [Accepted: 12/24/2022] [Indexed: 06/17/2023]
Abstract
Glyphosate is one of the most widely used herbicides in the world. However, because of its overuse and resistance to degradation, high levels of glyphosate residues in the environment are reported. Therefore, this study aimed to investigate the effects of glyphosate on proteomic aspects of Tetrahymena thermophila and their uses as bioindicators of freshwater ecosystem. First, an acute toxicity test was performed to determine the median inhibition concentration (IC50 ). The toxicity test results showed that glyphosate inhibited the growth (proliferation) of T. thermophila. The 96 h-IC50 value of glyphosate was 171 mg L-1 . No visible changes in aggregation behavior and cell morphology were observed under glyphosate exposure. In addition, the effects of low and high dose glyphosate concentrations (77.5 mg L-1 , 171 mg L-1 ) on the proteomic changes of T. thermophila was investigated using a label-free shotgun proteomic approach. A total of 3191 proteins were identified, 2791 proteins were expressed in the control, 2651 proteins were expressed in 77.5 mg L-1 glyphosates, and 3012 proteins were expressed in 171 mg L-1 glyphosates. Under glyphosate exposure at both low and high dose glyphosate, 400 unique proteins were upregulated. The majority of these proteins was classified as proteins associated with oxidative stress response and intracellular transport indicating the shifts in the internal metabolism. Proteomics revealed that the glyphosate metabolism by T. thermophila is a multi-step process involving several enzymes, which can be divided into four phases, including modification (phase I), conjugation (phase II), transport (phase III), and degradation (phase IV). The accumulation of various biochemical reactions contributes to overall glyphosate resistance. With the proteomics approach, we have found that T. thermophila was equipped with glyphosate detoxification and degradation mechanisms.
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Affiliation(s)
- Abdul Manan
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok, Thailand
- Department of Aquaculture, Faculty of Fisheries and Marine, Universitas Airlangga, Surabaya, Indonesia
| | - Sittiruk Roytrakul
- Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Sawanya Charoenlappanit
- Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Toemthip Poolpak
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok, Thailand
| | - Puey Ounjai
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok, Thailand
| | - Maleeya Kruatrachue
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok, Thailand
| | - Kwang Mo Yang
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok, Thailand
| | - Prayad Pokethitiyook
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok, Thailand
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10
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Üstüntanır Dede AF, Arslanyolu M. The in vivo Tetrahymena thermophila extracellular glucose drop assay for characterization of mammalian insulin activity. Eur J Protistol 2021; 79:125803. [PMID: 34044354 DOI: 10.1016/j.ejop.2021.125803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/22/2021] [Accepted: 05/04/2021] [Indexed: 11/17/2022]
Abstract
Insulin activity is generally determined by an in vivo rabbit blood glucose drop assay in research and industriel laboratories. The humane experimental techniques imply the use of alternative invertebrate organisms in place of animals, known as replacement rule of the 3Rs. In this study, we report an alternative in vivo extracellular glucose drop assay using unicellular invertebrate Tetrahymena thermophila to replace the use of rabbit and mouse. This assay has four major steps; growing cells, starving cells, treatment of cells and measurement of glucose drop. In this assay, 0.2 mg/ml of human, porcine and bovine insulins dropped extracellular glucose level to 16%, 14% and 12%, respectively in ten minutes. In addition, mammalian insulins respectively increased the cell area about 19%, 15%, and 16% at 6th hour with statistically significant effect on the cell growth, but not in the cell viability. The results showed that the in vivo Tetrahymena thermophila extracellular glucose drop assay could be used as an alternative assay to replace the mouse or the rabbit insulin blood glucose drop assay.
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Affiliation(s)
- Ayça Fulya Üstüntanır Dede
- Department of Biology, Graduate School of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskisehir 26470, Turkey.
| | - Muhittin Arslanyolu
- Department of Biology, Faculty of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskisehir, Turkey.
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11
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Hernández J, Gabrielli M, Costa J, Uttaro AD. Phagocytic and pinocytic uptake of cholesterol in Tetrahymena thermophila impact differently on gene regulation for sterol homeostasis. Sci Rep 2021; 11:9067. [PMID: 33907281 PMCID: PMC8079401 DOI: 10.1038/s41598-021-88737-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 04/15/2021] [Indexed: 01/02/2023] Open
Abstract
The ciliate Tetrahymena thermophila can either synthesize tetrahymanol or when available, assimilate and modify sterols from its diet. This metabolic shift is mainly driven by transcriptional regulation of genes for tetrahymanol synthesis (TS) and sterol bioconversion (SB). The mechanistic details of sterol uptake, intracellular trafficking and the associated gene expression changes are unknown. By following cholesterol incorporation over time in a conditional phagocytosis-deficient mutant, we found that although phagocytosis is the main sterol intake route, a secondary endocytic pathway exists. Different expression patterns for TS and SB genes were associated with these entry mechanisms. Squalene synthase was down-regulated by a massive cholesterol intake only attainable by phagocytosis-proficient cells, whereas C22-sterol desaturase required ten times less cholesterol and was up-regulated in both wild-type and mutant cells. These patterns are suggestive of at least two different signaling pathways. Sterol trafficking beyond phagosomes and esterification was impaired by the NPC1 inhibitor U18666A. NPC1 is a protein that mediates cholesterol export from late endosomes/lysosomes in mammalian cells. U18666A also produced a delay in the transcriptional response to cholesterol, suggesting that the regulatory signals are triggered between lysosomes and the endoplasmic reticulum. These findings could hint at partial conservation of sterol homeostasis between eukaryote lineages.
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Affiliation(s)
- Josefina Hernández
- Instituto de Biología Molecular y Celular de Rosario, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2000FHQ, Ocampo y Esmeralda, Rosario, Argentina
| | - Matías Gabrielli
- Instituto de Biología Molecular y Celular de Rosario, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2000FHQ, Ocampo y Esmeralda, Rosario, Argentina
| | - Joaquín Costa
- Instituto de Biología Molecular y Celular de Rosario, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2000FHQ, Ocampo y Esmeralda, Rosario, Argentina
| | - Antonio D Uttaro
- Instituto de Biología Molecular y Celular de Rosario, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2000FHQ, Ocampo y Esmeralda, Rosario, Argentina.
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12
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Nabeel-Shah S, Garg J, Kougnassoukou Tchara PE, Pearlman RE, Lambert JP, Fillingham J. Functional proteomics protocol for the identification of interaction partners in Tetrahymena thermophila. STAR Protoc 2021; 2:100362. [PMID: 33786459 PMCID: PMC7988224 DOI: 10.1016/j.xpro.2021.100362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
We describe an optimized protocol for one-step affinity purification of FZZ-tagged proteins followed by mass spectrometry analysis for the identification of protein-protein interactions in the ciliate protozoan Tetrahymena thermophila. The FZZ epitope tag contains 2 protein A moieties (ZZ) and a 3xFLAG separated by a TEV cleavage site, which can also be employed in tandem affinity purification. This protocol is versatile and is suitable to use for other common epitope tags and can be adapted for other ciliates. For complete details on the use and execution of this protocol, please refer to Garg et al. (2019).
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Affiliation(s)
- Syed Nabeel-Shah
- Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jyoti Garg
- Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - Pata-Eting Kougnassoukou Tchara
- Department of Molecular Medicine, Cancer Research Center, Big Data Research Center, Université Laval, Quebec City, QC, Canada
- CHU de Québec Research Center, CHUL, 2705 Laurier Boulevard, Quebec City, QC, G1V 4G2, Canada
| | - Ronald E. Pearlman
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - Jean-Philippe Lambert
- Department of Molecular Medicine, Cancer Research Center, Big Data Research Center, Université Laval, Quebec City, QC, Canada
- CHU de Québec Research Center, CHUL, 2705 Laurier Boulevard, Quebec City, QC, G1V 4G2, Canada
| | - Jeffrey Fillingham
- Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Hao H, Dang Y, Chen S, Sun Q, Kong R, Cheng S, Liu C. Effects of triphenyl phosphate on ciliate protozoa Tetrahymena thermophila following acute exposure and sub-chronic exposure. Ecotoxicol Environ Saf 2020; 200:110757. [PMID: 32454264 DOI: 10.1016/j.ecoenv.2020.110757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/05/2020] [Accepted: 05/09/2020] [Indexed: 06/11/2023]
Abstract
Triphenyl phosphate (TPHP) is one of the most widely used organophosphate flame retardants (OPFRs) and is frequently detected in a variety of environmental media. Previous studies reported that TPHP had toxic effects on vertebrates, but little toxic information was available in lower trophic aquatic organisms which were more sensitive to the exposure of many toxic substances. In this study, protozoa Tetrahymena thermophila (T. thermophila) were exposed to 0, 0.01, 0.17 or 2.35 mg/L TPHP for 5 days to study the effects of sub-chronic exposure on theoretical population, cell viability, cell size and number of cilia. Additionally, the effects of TPHP on gene transcription were assessed by transcriptome sequencing technique (RNA-Seq). Cell viability and number of cilia were significantly reduced in all TPHP exposure groups compared with the control. In addition, exposure to 0.17 or 2.35 mg/L TPHP significantly reduced the theoretical population, circumference and body width, and there was a significant decrease in body length in the 2.35 mg/L exposure group. Comparative transcriptome sequencing identified a total of 4105 up- and 4487 down-regulated genes after exposure to 2.35 mg/L TPHP for 5 days compared with the control. KEGG analysis showed that dysfunction of pathways associated with ribosome, spliceosome, phagosome, proteasome and protein processing in endoplasmic reticulum in this study might be responsible for the toxicity of T. thermophila caused by TPHP. In general, the results indicated that TPHP had an adverse effect on the protozoa T. thermophila.
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Affiliation(s)
- Hui Hao
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yao Dang
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, 510655, China
| | - Sheng Chen
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qian Sun
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ren Kong
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shiyang Cheng
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Chunsheng Liu
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China.
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15
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Abstract
Recognition of self and nonself is important for outcrossing organisms, and different mating types establish the barrier against self-mating. In the unicellular ciliate T. thermophila, mating type determination requires complex DNA rearrangements at a single mat locus during conjugation to produce a type-specific gene pair (MTA and MTB) for 1 of 7 possible mating types. Surprisingly, we found that decreased expression of the DNA breakage-repair protein Ku80 at late stages of conjugation generated persistent selfing phenotype in the progeny. DNA analysis revealed multiple mating-type gene pairs as well as a variety of mis-paired, unusually arranged mating-type genes in these selfers that resemble some proposed rearrangement intermediates. They are found also in normal cells during conjugation and are lost after 10 fissions but are retained in Ku mutants. Silencing of TKU80 or TKU70-2 immediately after conjugation also generated selfing phenotype, revealing a hidden DNA rearrangement process beyond conjugation. Mating reactions between the mutant and normal cells suggest a 2-component system for self–nonself-recognition through MTA and MTB genes. In the unicellular ciliate Tetrahymena thermophila, mating type determination requires complex DNA rearrangements to produce a type-specific MAT gene pair for each of seven possible mating types. This study shows that DNA recombination produces a large number of unusual MAT gene pairs, but through a KU-dependent process only one normal pair is retained in a mature cell; retention of unusual gene pairs leads to self-mating and suggests a system for self/non-self recognition.
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Affiliation(s)
- I-Ting Lin
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan
| | - Meng-Chao Yao
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan
- * E-mail:
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16
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Song K, Shang Z, Fu X, Lou X, Grigorieff N, Nicastro D. In situ structure determination at nanometer resolution using TYGRESS. Nat Methods 2020; 17:201-208. [PMID: 31768058 PMCID: PMC7004880 DOI: 10.1038/s41592-019-0651-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/20/2019] [Accepted: 10/11/2019] [Indexed: 02/06/2023]
Abstract
The resolution of subtomogram averages calculated from cryo-electron tomograms (cryo-ET) of crowded cellular environments is often limited owing to signal loss in, and misalignment of, the subtomograms. By contrast, single-particle cryo-electron microscopy (SP-cryo-EM) routinely reaches near-atomic resolution of isolated complexes. We report a method called 'tomography-guided 3D reconstruction of subcellular structures' (TYGRESS) that is a hybrid of cryo-ET and SP-cryo-EM, and is able to achieve close-to-nanometer resolution of complexes inside crowded cellular environments. TYGRESS combines the advantages of SP-cryo-EM (images with good signal-to-noise ratio and contrast, as well as minimal radiation damage) and subtomogram averaging (three-dimensional alignment of macromolecules in a complex sample). Using TYGRESS, we determined the structure of the intact ciliary axoneme with up to resolution of 12 Å. These results reveal many structural details that were not visible by cryo-ET alone. TYGRESS is generally applicable to cellular complexes that are amenable to subtomogram averaging.
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Affiliation(s)
- Kangkang Song
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Cryo-EM Core Facility, University of Massachusetts Medical School, Worcester, MA, USA
| | - Zhiguo Shang
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaofeng Fu
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Biological Science Imaging Resource, Florida State University, Tallahassee, FL, USA
| | - Xiaochu Lou
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Nikolaus Grigorieff
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Daniela Nicastro
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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17
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Khalifa AAZ, Ichikawa M, Dai D, Kubo S, Black CS, Peri K, McAlear TS, Veyron S, Yang SK, Vargas J, Bechstedt S, Trempe JF, Bui KH. The inner junction complex of the cilia is an interaction hub that involves tubulin post-translational modifications. eLife 2020; 9:e52760. [PMID: 31951202 PMCID: PMC6994238 DOI: 10.7554/elife.52760] [Citation(s) in RCA: 173] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/16/2020] [Indexed: 12/11/2022] Open
Abstract
Microtubules are cytoskeletal structures involved in stability, transport and organization in the cell. The building blocks, the α- and β-tubulin heterodimers, form protofilaments that associate laterally into the hollow microtubule. Microtubule also exists as highly stable doublet microtubules in the cilia where stability is needed for ciliary beating and function. The doublet microtubule maintains its stability through interactions at its inner and outer junctions where its A- and B-tubules meet. Here, using cryo-electron microscopy, bioinformatics and mass spectrometry of the doublets of Chlamydomonas reinhardtii and Tetrahymena thermophila, we identified two new inner junction proteins, FAP276 and FAP106, and an inner junction-associated protein, FAP126, thus presenting the complete answer to the inner junction identity and localization. Our structural study of the doublets shows that the inner junction serves as an interaction hub that involves tubulin post-translational modifications. These interactions contribute to the stability of the doublet and hence, normal ciliary motility.
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Affiliation(s)
- Ahmad Abdelzaher Zaki Khalifa
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | | | - Daniel Dai
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Shintaroh Kubo
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
- Department of Biophysics, Graduate School of ScienceKyoto UniversityKyotoJapan
| | - Corbin Steven Black
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Katya Peri
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
| | - Thomas S McAlear
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Simon Veyron
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
- Department of Pharmacology & TherapeuticsMcGill UniversityMontréalCanada
| | - Shun Kai Yang
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Javier Vargas
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Susanne Bechstedt
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Jean-François Trempe
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
- Department of Pharmacology & TherapeuticsMcGill UniversityMontréalCanada
| | - Khanh Huy Bui
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
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18
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Abstract
The failure of mRNA translation machinery to recognize a stop codon as a termination signal and subsequent translation of the 3' untranslated region (UTR) is referred to as stop codon readthrough, the frequency of which is related to the length, composition, and structure of mRNA sequences downstream of end-of-gene stop codons. Secondary in-frame stop codons within a few positions downstream of the primary stop codons, so-called tandem stop codons (TSCs), serve as backup termination signals, which limit the effects of readthrough: polypeptide product degradation, mislocalization, and aggregation. In this study, ciliate species with UAA and UAG stop codons reassigned to code for glutamine are found to possess statistical excesses of TSCs at the beginning of their 3' UTRs. The overrepresentation of TSCs in these species is greater than that observed in standard code organisms. Though the overall numbers of TSCs are lower in most species with alternative stop codons because they use fewer than three unique stop codons, the relatively great overrepresentation of TSCs in alternative-code ciliate species suggests that there exist stronger selective pressures to maintain TSCs in these organisms compared to standard code organisms.
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Affiliation(s)
- Ira Fleming
- Department of Molecular Biology, Pomona College, Claremont, CA, United States of America
| | - Andre R. O. Cavalcanti
- Department of Molecular Biology, Pomona College, Claremont, CA, United States of America
- * E-mail:
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19
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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. Sci China Life Sci 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] [What about the content of this article? (0)] [Affiliation(s)] [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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20
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Ye Q, Zhang C, Wang Z, Feng Y, Zhou A, Xie S, Xiang Q, Song E, Zou J. Induction of oxidative stress, apoptosis and DNA damage by koumine in Tetrahymena thermophila. PLoS One 2019; 14:e0212231. [PMID: 30753239 PMCID: PMC6372211 DOI: 10.1371/journal.pone.0212231] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/29/2019] [Indexed: 01/13/2023] Open
Abstract
Koumine is a component of the Chinese medicinal herb Gelsemium elegans and is toxic to vertebrates. We used the ciliate Tetrahymena thermophila as a model to evaluate the toxic effects of this indole alkaloid in eukaryotic microorganisms. Koumine inhibited T. thermophila growth and viability in a dose-dependent manner. Moreover, this drug produced oxidative stress in T. thermophila cells and expressions of antioxidant enzymes were significantly elevated at high koumine levels (p < 0.05). Koumine also caused significant levels of apoptosis (p < 0.05) and induced DNA damage in a dose-dependent manner. Mitophagic vacuoles were present in cells indicating induction of autophagy by this drug. Expression of ATG7, MTT2/4, CYP1 and HSP70 as well as the MAP kinase pathway gene MPK1 and MPK3 were significantly altered after exposed to koumine. This study represents a preliminary toxicological evaluation of koumine in the single celled eukaryote T. thermophila.
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Affiliation(s)
- Qiao Ye
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Chaonan Zhang
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zhenlu Wang
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yongyong Feng
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Aiguo Zhou
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Shaolin Xie
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Qiong Xiang
- Department of Traditional Chinese Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Enfeng Song
- Department of Traditional Chinese Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Jixing Zou
- Healthy Aquaculture Laboratory, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- * E-mail:
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21
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Mancini A, Eyassu F, Conway M, Occhipinti A, Liò P, Angione C, Pucciarelli S. CiliateGEM: an open-project and a tool for predictions of ciliate metabolic variations and experimental condition design. BMC Bioinformatics 2018; 19:442. [PMID: 30497359 PMCID: PMC6266953 DOI: 10.1186/s12859-018-2422-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The study of cell metabolism is becoming central in several fields such as biotechnology, evolution/adaptation and human disease investigations. Here we present CiliateGEM, the first metabolic network reconstruction draft of the freshwater ciliate Tetrahymena thermophila. We also provide the tools and resources to simulate different growth conditions and to predict metabolic variations. CiliateGEM can be extended to other ciliates in order to set up a meta-model, i.e. a metabolic network reconstruction valid for all ciliates. Ciliates are complex unicellular eukaryotes of presumably monophyletic origin, with a phylogenetic position that is equal from plants and animals. These cells represent a new concept of unicellular system with a high degree of species, population biodiversity and cell complexity. Ciliates perform in a single cell all the functions of a pluricellular organism, including locomotion, feeding, digestion, and sexual processes. RESULTS After generating the model, we performed an in-silico simulation with the presence and absence of glucose. The lack of this nutrient caused a 32.1% reduction rate in biomass synthesis. Despite the glucose starvation, the growth did not stop due to the use of alternative carbon sources such as amino acids. CONCLUSIONS The future models obtained from CiliateGEM may represent a new approach to describe the metabolism of ciliates. This tool will be a useful resource for the ciliate research community in order to extend these species as model organisms in different research fields. An improved understanding of ciliate metabolism could be relevant to elucidate the basis of biological phenomena like genotype-phenotype relationships, population genetics, and cilia-related disease mechanisms.
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Affiliation(s)
- Alessio Mancini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
- Computer Laboratory, University of Cambridge, Cambridge, UK
| | - Filmon Eyassu
- Department of Computer Science and Information Systems, Teesside University, Middlesbrough, UK
| | - Maxwell Conway
- Computer Laboratory, University of Cambridge, Cambridge, UK
| | | | - Pietro Liò
- Computer Laboratory, University of Cambridge, Cambridge, UK
| | - Claudio Angione
- Department of Computer Science and Information Systems, Teesside University, Middlesbrough, UK
| | - Sandra Pucciarelli
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
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22
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Luo GZ, Hao Z, Luo L, Shen M, Sparvoli D, Zheng Y, Zhang Z, Weng X, Chen K, Cui Q, Turkewitz AP, He C. N 6-methyldeoxyadenosine directs nucleosome positioning in Tetrahymena DNA. Genome Biol 2018; 19:200. [PMID: 30454035 PMCID: PMC6245762 DOI: 10.1186/s13059-018-1573-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 10/22/2018] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND N6-methyldeoxyadenosine (6mA or m6dA) was shown more than 40 years ago in simple eukaryotes. Recent studies revealed the presence of 6mA in more prevalent eukaryotes, even in vertebrates. However, functional characterizations have been limited. RESULTS We use Tetrahymena thermophila as a model organism to examine the effects of 6mA on nucleosome positioning. Independent methods reveal the enrichment of 6mA near and after transcription start sites with a periodic pattern and anti-correlation relationship with the positions of nucleosomes. The distribution pattern can be recapitulated by in vitro nucleosome assembly on native Tetrahymena genomic DNA but not on DNA without 6mA. Model DNA containing artificially installed 6mA resists nucleosome assembling compared to unmodified DNA in vitro. Computational simulation indicates that 6mA increases dsDNA rigidity, which disfavors nucleosome wrapping. Knockout of a potential 6mA methyltransferase leads to a transcriptome-wide change of gene expression. CONCLUSIONS These findings uncover a mechanism by which DNA 6mA assists to shape the nucleosome positioning and potentially affects gene expression.
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Affiliation(s)
- Guan-Zheng Luo
- The State Key Laboratory of Biocontrol, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510060, China.
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
- Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
| | - Ziyang Hao
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
| | - Liangzhi Luo
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
- Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang, 550025, China
| | - Mingren Shen
- Graduate Program in Biophysics, Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, 1101 Univ. Ave., Madison, WI, 53706, USA
| | - Daniela Sparvoli
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 920 East 58th Street, Chicago, IL, 60637, USA
| | - Yuqing Zheng
- Graduate Program in Biophysics, Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, 1101 Univ. Ave., Madison, WI, 53706, USA
| | - Zijie Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
| | - Xiaocheng Weng
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
| | - Kai Chen
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
| | - Qiang Cui
- Graduate Program in Biophysics, Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, 1101 Univ. Ave., Madison, WI, 53706, USA
| | - Aaron P Turkewitz
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 920 East 58th Street, Chicago, IL, 60637, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
- Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
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23
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Jiang J, Wang Y, Sušac L, Chan H, Basu R, Zhou ZH, Feigon J. Structure of Telomerase with Telomeric DNA. Cell 2018; 173:1179-1190.e13. [PMID: 29775593 PMCID: PMC5995583 DOI: 10.1016/j.cell.2018.04.038] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/22/2018] [Accepted: 04/26/2018] [Indexed: 01/05/2023]
Abstract
Telomerase is an RNA-protein complex (RNP) that extends telomeric DNA at the 3' ends of chromosomes using its telomerase reverse transcriptase (TERT) and integral template-containing telomerase RNA (TER). Its activity is a critical determinant of human health, affecting aging, cancer, and stem cell renewal. Lack of atomic models of telomerase, particularly one with DNA bound, has limited our mechanistic understanding of telomeric DNA repeat synthesis. We report the 4.8 Å resolution cryoelectron microscopy structure of active Tetrahymena telomerase bound to telomeric DNA. The catalytic core is an intricately interlocked structure of TERT and TER, including a previously structurally uncharacterized TERT domain that interacts with the TEN domain to physically enclose TER and regulate activity. This complete structure of a telomerase catalytic core and its interactions with telomeric DNA from the template to telomere-interacting p50-TEB complex provides unanticipated insights into telomerase assembly and catalytic cycle and a new paradigm for a reverse transcriptase RNP.
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Affiliation(s)
- Jiansen Jiang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yaqiang Wang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lukas Sušac
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Henry Chan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ritwika Basu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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Abstract
Eukaryotic nucleocytoplasm is believed to be descended from ancient Archaea that respired on elemental sulfur. If so, a vestige of sulfur reduction might persist in modern eukaryotic cells. That was tested in Tetrahymena thermophila, chosen as a model organism. When oxygenated, the cells consumed H2S rapidly, but when made anoxic they produced H2S mostly by amino acid catabolism. That could be inhibited by adding aminooxyacetic acid, and then H2S production from elemental sulfur became more evident. Anoxic cell lysates produced H2S when provided with sulfur and NADH, but not with either substrate alone. When lysates were fractionated by centrifugation, NADH-dependent H2S production was 83% in the soluble fraction. When intact cells that had just previously oxidized H2S were shifted to anoxia, the cells produced H2S evidently by re-using the oxidized sulfur. After aerobic H2S oxidation was stopped, the oxidation product remained available for H2S production for about 10 min. The observed H2S production is consistent with an evolutionary relationship of nucleocytoplasm to sulfur-reducing Archaea. Mitochondria often are the cellular site of H2S oxidation, suggesting that eukaryotic cells might have evolved from an ancient symbiosis that was based upon sulfur exchange.
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Affiliation(s)
- Dennis G Searcy
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
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25
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Juganson K, Mortimer M, Ivask A, Pucciarelli S, Miceli C, Orupõld K, Kahru A. Mechanisms of toxic action of silver nanoparticles in the protozoan Tetrahymena thermophila: From gene expression to phenotypic events. Environ Pollut 2017; 225:481-489. [PMID: 28318795 DOI: 10.1016/j.envpol.2017.03.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/05/2017] [Accepted: 03/06/2017] [Indexed: 06/06/2023]
Abstract
Silver nanoparticles (AgNPs) are highly toxic to aquatic organisms, however, there is no consensus whether the toxicity is caused solely by released Ag-ions or also by reactive oxygen species (ROS). Here, the effects of protein-coated AgNPs (14.6 nm, Collargol) were studied on viability, oxidative stress and gene expression levels in wild type strains (CU427 and CU428) of ciliate Tetrahymena thermophila. Viability-based 24 h EC50 values of AgNPs were relatively high and significantly different for the two strains: ∼100 mg/L and ∼75 mg/L for CU427 and CU428, respectively. Similarly, the expression profiles of oxidative stress (OS) related genes in the two strains were different. However, even though some OS related genes were overexpressed in AgNP-exposed ciliates, intracellular ROS level was not elevated, possibly due to efficient cellular antioxidant defence mechanisms. Compared to OS related genes, metallothionein genes were upregulated at a considerably higher level (36 versus 5000-fold) suggesting that Ag-ion mediated toxicity mechanism prevailed over OS related pathway. Also, comparison between Ag-ions released from AgNPs at EC50 concentration and the respective EC50 values of AgNO3 indicated that Ag-ions played a major role in the toxicity of AgNPs in T. thermophila. The study highlights the importance of combining physiological assays with gene expression analysis in elucidating the mechanisms of action of NPs to reveal subtle cellular responses that may not be detectable in bioassays. In addition, our data filled the gaps on the toxicity of AgNPs for environmentally relevant and abundant organisms. The parallel study of two wild type strains allowed us to draw conclusions on strain to strain variability in susceptibility to AgNPs.
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Affiliation(s)
- Katre Juganson
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia; Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
| | - Monika Mortimer
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| | - Angela Ivask
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| | - Sandra Pucciarelli
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III da Varano, 62032 Camerino, Italy
| | - Cristina Miceli
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III da Varano, 62032 Camerino, Italy
| | - Kaja Orupõld
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 5, 51014 Tartu, Estonia
| | - Anne Kahru
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia; Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia
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26
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De Luca BM, Nudel CB, Gonzalez RH, Nusblat AD. Introducing the concept of biocatalysis in the classroom: The conversion of cholesterol to provitamin D 3. Biochem Mol Biol Educ 2017; 45:105-114. [PMID: 27666582 DOI: 10.1002/bmb.20995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 06/28/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
Biocatalysis is a fundamental concept in biotechnology. The topic integrates knowledge of several disciplines; therefore, it was included in the course "design and optimization of biological systems" which is offered in the biochemistry curricula. We selected the ciliate tetrahymena as an example of a eukaryotic system with potential for the biotransformation of sterol metabolites of industrial interest; in particular, we focused on the conversion of cholesterol to provitamin D3. The students work with wild type and recombinant strains and learn how sterol pathways could be modified to obtain diverse sterol moieties. During the course the students identify and measure the concentration of sterols. They also search for related genes by bioinformatic analysis. Additionally, the students compare biotransformation rates, growing the ciliate in plate and in a bioreactor. Finally, they use fluorescence microscopy to localize an enzyme involved in biotransformation. The last day each team makes an oral presentation, explaining the results obtained and responds to a series of key questions posed by the teachers, which determine the final mark. In our experience, this course enables undergraduate students to become acquainted with the principles of biocatalysis as well as with standard and modern techniques, through a simple and robust laboratory exercise, using a biological system for the conversion of valuable pharmaceutical moieties. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(2):105-114, 2017.
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Affiliation(s)
- Belén M De Luca
- Cátedra de Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, Argentina, C1113AAD
| | - Clara B Nudel
- Cátedra de Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, Argentina, C1113AAD
| | - Rodrigo H Gonzalez
- Cátedra de Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, Argentina, C1113AAD
| | - Alejandro D Nusblat
- Cátedra de Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, Argentina, C1113AAD
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27
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Edamatsu M. Establishment of a mutation system in Tetrahymena outer arm dynein and P-loop functions of the alpha heavy chain (Dyh3p). Biochem Biophys Res Commun 2017; 483:24-31. [PMID: 28069381 DOI: 10.1016/j.bbrc.2017.01.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 01/05/2017] [Indexed: 11/17/2022]
Abstract
Axonemal dyneins are large AAA+ type motor proteins that exhibit unique motor properties during ciliary beating. This study established a mutation system for Tetrahymena outer arm dynein and characterized four nucleotide-binding loops (P-loops; P1-P4) in the alpha heavy chain (Dyh3p). Macronuclear transformation of the mutant DYH3 genes in DYH3-knockout (KO-DYH3) cells enabled P-loop mutations that abolish the ability of nucleotide binding to be stably maintained in the polyploid genome. This mutation system revealed that the P3 and P4 mutant dyneins rescued lethality in macronuclear KO-DYH3 cells and exhibited normal ciliary localization. Intriguingly, however, an in vitro motility assay showed that the P3 mutation abolished the motor activity of Dyh3p, whereas the P4 mutation did not affect the gliding velocity or gliding index of Dyh3p. In contrast, no P1 or P2 mutant cells were isolated from the KO-DYH3 cells, which suggests that nucleotide binding at the P1 and P2 sites is required for the intracellular function of Dyh3p. This mutation system will be useful for further molecular studies of diverse axonemal dyneins and ciliary motility.
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Affiliation(s)
- Masaki Edamatsu
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-0041, Japan.
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28
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Abstract
The intra-S phase checkpoint kinase of metazoa and yeast, ATR/MEC1, protects chromosomes from DNA damage and replication stress by phosphorylating subunits of the replicative helicase, MCM2-7. Here we describe an unprecedented ATR-dependent pathway in Tetrahymena thermophila in which the essential pre-replicative complex proteins, Orc1p, Orc2p and Mcm6p are degraded in hydroxyurea-treated S phase cells. Chromosomes undergo global changes during HU-arrest, including phosphorylation of histone H2A.X, deacetylation of histone H3, and an apparent diminution in DNA content that can be blocked by the deacetylase inhibitor sodium butyrate. Most remarkably, the cell cycle rapidly resumes upon hydroxyurea removal, and the entire genome is replicated prior to replenishment of ORC and MCMs. While stalled replication forks are elongated under these conditions, DNA fiber imaging revealed that most replicating molecules are produced by new initiation events. Furthermore, the sole origin in the ribosomal DNA minichromosome is inactive and replication appears to initiate near the rRNA promoter. The collective data raise the possibility that replication initiation occurs by an ORC-independent mechanism during the recovery from HU-induced replication stress. DNA damage and replication stress activate cell cycle checkpoint responses that protect the integrity of eukaryotic chromosomes. A well-conserved response involves the reversible phosphorylation of the replicative helicase, MCM2-7, which together with the origin recognition complex (ORC) dictates when and where replication initiates in chromosomes. The central role of ORC and MCMs in DNA replication is illustrated by the fact that small changes in abundance of these pre-replicative complex (pre-RC) components are poorly tolerated from yeast to humans. Here we describe an unprecedented replication stress checkpoint response in the early branching eukaryote, Tetrahymena thermophila, that is triggered by the depletion of dNTP pools with hydroxyurea (HU). Instead of transiently phosphorylating MCM subunits, ORC and MCM proteins are physically degraded in HU-treated Tetrahymena. Unexpectedly, upon HU removal the genome is completely and effortlessly replicated prior to replenishment of ORC and MCM components. Using DNA fiber imaging and 2D gel electrophoresis, we show that ORC-dependent mechanisms are bypassed during the recovery phase to produce bidirectional replication forks throughout the genome. Our findings suggest that Tetrahymena enlists an alternative mechanism for replication initiation, and that the underlying process can operate on a genome-wide scale.
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Affiliation(s)
- Pamela Y. Sandoval
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, United States of America
| | - Po-Hsuen Lee
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Xiangzhou Meng
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Geoffrey M. Kapler
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, United States of America
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
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29
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Robinson R. Wait and capture: unwinding the strategy of a DEAD-box helicase. PLoS Biol 2014; 12:e1001982. [PMID: 25350371 PMCID: PMC4211674 DOI: 10.1371/journal.pbio.1001982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Richard Robinson
- Freelance Science Writer, Sherborn, Massachusetts, United States of America
- * E-mail:
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30
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Ponsuwanna P, Kümpornsin K, Chookajorn T. Genome-wide prediction of the polymorphic Ser gene family in Tetrahymena thermophila based on motif analysis. PLoS One 2014; 9:e105201. [PMID: 25133747 PMCID: PMC4136848 DOI: 10.1371/journal.pone.0105201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 07/21/2014] [Indexed: 11/18/2022] Open
Abstract
Even though antigenic variation is employed among parasitic protozoa for host immune evasion, Tetrahymena thermophila, a free-living ciliate, can also change its surface protein antigens. These cysteine-rich glycosylphosphatidylinositol (GPI)-linked surface proteins are encoded by a family of polymorphic Ser genes. Despite the availability of T. thermophila genome, a comprehensive analysis of the Ser family is limited by its high degree of polymorphism. In order to overcome this problem, a new approach was adopted by searching for Ser candidates with common motif sequences, namely length-specific repetitive cysteine pattern and GPI anchor site. The candidate genes were phylogenetically compared with the previously identified Ser genes and classified into subtypes. Ser candidates were often found to be located as tandem arrays of the same subtypes on several chromosomal scaffolds. Certain Ser candidates located in the same chromosomal arrays were transcriptionally expressed at specific T. thermophila developmental stages. These Ser candidates selected by the motif analysis approach can form the foundation for a systematic identification of the entire Ser gene family, which will contribute to the understanding of their function and the basis of T. thermophila antigenic variation.
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Affiliation(s)
- Patrath Ponsuwanna
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Krittikorn Kümpornsin
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Thanat Chookajorn
- Center of Excellence in Malaria, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- * E-mail:
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Dittrich-Domergue F, Joubès J, Moreau P, Lessire R, Stymne S, Domergue F. The bifunctional protein TtFARAT from Tetrahymena thermophila catalyzes the formation of both precursors required to initiate ether lipid biosynthesis. J Biol Chem 2014; 289:21984-94. [PMID: 24917677 PMCID: PMC4139215 DOI: 10.1074/jbc.m114.579318] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 06/03/2014] [Indexed: 11/06/2022] Open
Abstract
The biosynthesis of ether lipids and wax esters requires as precursors fatty alcohols, which are synthesized by fatty acyl reductases (FARs). The presence of ether glycerolipids as well as branched wax esters has been reported in several free-living ciliate protozoa. In the genome of Tetrahymena thermophila, the only ORF sharing similarities with FARs is fused to an acyltransferase-like domain, whereas, in most other organisms, FARs are monofunctional proteins of similar size and domain structure. Here, we used heterologous expression in plant and yeast to functionally characterize the activities catalyzed by this protozoan protein. Transient expression in tobacco epidermis of a truncated form fused to the green fluorescence protein followed by confocal microscopy analysis suggested peroxisomal localization. In vivo approaches conducted in yeast indicated that the N-terminal FAR-like domain produced both 16:0 and 18:0 fatty alcohols, whereas the C-terminal acyltransferase-like domain was able to rescue the lethal phenotype of the yeast double mutant gat1Δ gat2Δ. Using in vitro approaches, we further demonstrated that this domain is a dihydroxyacetone phosphate acyltransferase that uses preferentially 16:0-coenzyme A as an acyl donor. Finally, coexpression in yeast with the alkyl-dihydroxyacetone phosphate synthase from T. thermophila resulted the detection of various glycerolipids with an ether bond, indicating reconstitution of the ether lipid biosynthetic pathway. Together, these results demonstrate that this FAR-like protein is peroxisomal and bifunctional, providing both substrates required by alkyl-dihydroxyacetone phosphate synthase to initiate ether lipid biosynthesis.
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Affiliation(s)
- Franziska Dittrich-Domergue
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
| | - Jérôme Joubès
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
| | - Patrick Moreau
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
| | - René Lessire
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
| | - Sten Stymne
- the Department of Plant Breeding, Swedish University of Agricultural Sciences, P.O.B. 101, 23053 Alnarp, Sweden
| | - Frédéric Domergue
- From the Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, the Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, UMR 5200, 33000 Bordeaux, France, and
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Mortimer M, Gogos A, Bartolomé N, Kahru A, Bucheli TD, Slaveykova VI. Potential of hyperspectral imaging microscopy for semi-quantitative analysis of nanoparticle uptake by protozoa. Environ Sci Technol 2014; 48:8760-8767. [PMID: 25000358 DOI: 10.1021/es500898j] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Hyperspectral imaging with enhanced darkfield microscopy (HSI-M) possesses unique advantages in its simplicity and non-invasiveness. In consideration of the urgent need for profound knowledge on the behavior and effects of engineered nanoparticles (NPs), here, we determined the capability of HSI-M for examining cellular uptake of different metal-based NPs, including nanosized metals (silver and gold, both citrate stabilized), metal oxides (copper oxide and titanium dioxide), and CdSe/ZnS core/shell quantum dots at subtoxic concentrations. Specifically, we demonstrated that HSI-M can be used to detect and semi-quantify these NPs in the ciliated protozoan Tetrahymena thermophila as a model aquatic organism. Detection and semi-quantification were achieved on the basis of spectral libraries for the NPs suspended in extracellular substances secreted by this single-celled organism, accounting for matrix effects. HSI-M was able to differentiate between NP types, provided that spectral profiles were significantly different from each other. This difference, in turn, depended upon NP type, size, agglomeration status, and position relative to the focal plane. As an exception among the NPs analyzed in this study, titanium dioxide NPs showed spectral similarities compared to cell material of unexposed control cells, leading to false positives. High biological variability resulted in highly variable uptake of NPs in cells of the same sample as well as between different exposures. We therefore encourage the development of techniques able to reduce the currently long analysis times that still hamper the acquisition of statistically strong data sets. Overall, this study demonstrates the potential and challenges of HSI-M in monitoring cellular uptake of synthetic NPs.
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Affiliation(s)
- Monika Mortimer
- Environmental Biogeochemistry and Ecotoxicology, Institute F.-A. Forel, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva , 10 route de Suisse, 1290 Versoix, Switzerland
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Mortimer M, Kahru A, Slaveykova VI. Uptake, localization and clearance of quantum dots in ciliated protozoa Tetrahymena thermophila. Environ Pollut 2014; 190:58-64. [PMID: 24727587 DOI: 10.1016/j.envpol.2014.03.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 03/13/2014] [Accepted: 03/19/2014] [Indexed: 06/03/2023]
Abstract
Protozoa as phagocytizing cells have been shown to integrate engineered nanoparticles (NPs), while the mechanism, dynamics and extent of such uptake are unclear. Here our fluorescence microscopy data showed that CdSe/ZnS quantum dots (QDs) with primary size of 12 nm were readily phagocytized into the food vacuoles of Tetrahymena thermophila in a time- and dose-dependent manner. Twenty hours after the exposure to QDs in sublethal concentration the clearance of the QDs from the cells was incomplete suggesting that phagocytosis of QDs into food vacuoles was not the only pathway of uptake by T. thermophila. This was further proven by the results that the inhibition of phagocytosis did not block the internalization of QDs into protozoans. This study provides a new insight into uptake and cellular trafficking of subtoxic concentrations of nanoparticles that may, due to prolonged retention times in the cells, pose risks by potentially becoming available to higher trophic levels.
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Affiliation(s)
- Monika Mortimer
- Environmental Biogeochemistry and Ecotoxicology, Institute F.-A. Forel, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva, 10 route de Suisse, 1290 Versoix, Switzerland; Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia.
| | - Anne Kahru
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| | - Vera I Slaveykova
- Environmental Biogeochemistry and Ecotoxicology, Institute F.-A. Forel, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva, 10 route de Suisse, 1290 Versoix, Switzerland.
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Yang WW, Wang Y, Huang B, Wang NX, Wei ZB, Luo J, Miao AJ, Yang LY. TiO2 nanoparticles act as a carrier of Cd bioaccumulation in the ciliate Tetrahymena thermophila. Environ Sci Technol 2014; 48:7568-7575. [PMID: 24912115 DOI: 10.1021/es500694t] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
When nanoparticles can enter a unicellular organism directly, how may they affect the bioaccumulation and toxicity of other pollutants already present in the environment? To answer this question, we conducted experiments with a protozoan Tetrahymena thermophila. The well-dispersed polyacrylate-coated TiO2 nanoparticles (PAA-TiO2-NPs) were used as a representative nanomaterial, and Cd as a conventional pollutant. We found that PAA-TiO2-NPs could get into Tetrahymena cells directly. Such internalization was first induced by low concentrations of Cd, but later suppressed when Cd concentrations were higher than 1 μg/L. Considering its significant adsorption on PAA-TiO2-NPs, Cd could be taken up by T. thermophila in the form of free ion or metal-nanoparticle complexes. The latter route accounted for 46.3% of Cd internalization. During the 5 h depuration period, 4.34-22.1% of Cd was excreted out, which was independent of the concentrations of intracellular Cd and PAA-TiO2-NPs. On the other hand, both free and intracellular Cd concentrations only partly predicted its toxicity at different levels of PAA-TiO2-NPs. This may have resulted from PAA-TiO2-NPs' synergistic effects and the distinct subcellular distribution of Cd taken up via the two routes above. Overall, we should pay attention to the carrier effects of nanoparticles when assessing their environmental risks.
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Affiliation(s)
- Wei-Wan Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing, Jiangsu Province 210046, China
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Feng L, Fu C, Yuan D, Miao W. A P450 gene associated with robust resistance to DDT in ciliated protozoan, Tetrahymena thermophila by efficient degradation. Aquat Toxicol 2014; 149:126-132. [PMID: 24607688 DOI: 10.1016/j.aquatox.2014.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 02/05/2014] [Accepted: 02/06/2014] [Indexed: 06/03/2023]
Abstract
Analysis of metabolic mechanisms of dichlorodiphenyltrichloroethane (DDT) accumulation and degradation in microorganisms, which could be used to reduce its hazard to higher organisms at the higher in the food chain, have not been investigated. Robust resistance to DDT (grows well in 256 mg/L DDT) and a surprising ability to degrade DDT (more than 70% DDT within 4h) were found in the ciliated protozoan Tetrahymena thermophila. A P450 gene (CYP5013C2) was found to respond specifically to DDT treatment. In the presence of 256 mg/L DDT, cells with overexpressing CYP5013C2 (p450-OE) grew faster and degraded DDT more efficiently than wild-type (WT) cells, while cells with CYP5013C2 partially knocked down (p450-KD) grew slower and exhibited reduced ability to degrade DDT compared to WT cells. Both dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) were detected in cells after exposure to DDT, and the concentration of DDD in the p450-OE strain gradually decreased from 0.5 to 4h. Thus, we argue that this P450 gene (CYP5013C2), by efficiently degrading DDT to DDD, is associated with robust resistance to DDT in Tetrahymena, and that a strain overexpressing this gene has the potential to serve as bioreactor that degrades environmental DDT.
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Affiliation(s)
- Lifang Feng
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China.
| | - Chengjie Fu
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Dongxia Yuan
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Wei Miao
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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Abstract
Ribosomes are large and highly charged macromolecular complexes consisting of RNA and proteins. Here, we address the electrostatic and nonpolar properties of ribosomal proteins that are important for ribosome assembly and interaction with other cellular components and may influence protein folding on the ribosome. We examined 50 S ribosomal subunits from 10 species and found a clear distinction between the net charge of ribosomal proteins from halophilic and non-halophilic organisms. We found that ∼67% ribosomal proteins from halophiles are negatively charged, whereas only up to ∼15% of ribosomal proteins from non-halophiles share this property. Conversely, hydrophobicity tends to be lower for ribosomal proteins from halophiles than for the corresponding proteins from non-halophiles. Importantly, the surface electrostatic potential of ribosomal proteins from all organisms, especially halophiles, has distinct positive and negative regions across all the examined species. Positively and negatively charged residues of ribosomal proteins tend to be clustered in buried and solvent-exposed regions, respectively. Hence, the majority of ribosomal proteins is characterized by a significant degree of intramolecular charge segregation, regardless of the organism of origin. This key property enables the ribosome to accommodate proteins within its complex scaffold regardless of their overall net charge.
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Affiliation(s)
- Daria V Fedyukina
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Theodore S Jennaro
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Silvia Cavagnero
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706.
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Schlatterer JC, Martin JS, Laederach A, Brenowitz M. Mapping the kinetic barriers of a Large RNA molecule's folding landscape. PLoS One 2014; 9:e85041. [PMID: 24586236 PMCID: PMC3934814 DOI: 10.1371/journal.pone.0085041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 11/23/2013] [Indexed: 11/19/2022] Open
Abstract
The folding of linear polymers into discrete three-dimensional structures is often required for biological function. The formation of long-lived intermediates is a hallmark of the folding of large RNA molecules due to the ruggedness of their energy landscapes. The precise thermodynamic nature of the barriers (whether enthalpic or entropic) that leads to intermediate formation is still poorly characterized in large structured RNA molecules. A classic approach to analyzing kinetic barriers are temperature dependent studies analyzed with Eyring's transition state theory. We applied Eyring's theory to time-resolved hydroxyl radical (•OH) footprinting kinetics progress curves collected at eight temperature from 21.5 °C to 51 °C to characterize the thermodynamic nature of folding intermediate formation for the Mg(2+)-mediated folding of the Tetrahymena thermophila group I ribozyme. A common kinetic model configuration describes this RNA folding reaction over the entire temperature range studied consisting of primary (fast) transitions to misfolded intermediates followed by much slower secondary transitions, consistent with previous studies. Eyring analysis reveals that the primary transitions are moderate in magnitude and primarily enthalpic in nature. In contrast, the secondary transitions are daunting in magnitude and entropic in nature. The entropic character of the secondary transitions is consistent with structural rearrangement of the intermediate species to the final folded form. This segregation of kinetic control reveals distinctly different molecular mechanisms during the two stages of RNA folding and documents the importance of entropic barriers to defining rugged RNA folding landscapes.
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Affiliation(s)
- Jörg C. Schlatterer
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Joshua S. Martin
- National Evolutionary Synthesis Center, Durham, North Carolina, United States of America
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Alain Laederach
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Michael Brenowitz
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
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Amaro F, Turkewitz AP, Martín-González A, Gutiérrez JC. Functional GFP-metallothionein fusion protein from Tetrahymena thermophila: a potential whole-cell biosensor for monitoring heavy metal pollution and a cell model to study metallothionein overproduction effects. Biometals 2014; 27:195-205. [PMID: 24430977 PMCID: PMC4707044 DOI: 10.1007/s10534-014-9704-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 12/31/2013] [Indexed: 11/26/2022]
Abstract
The significance of metal(oid)s as environmental pollutants has made them a priority in ecotoxicology, with the aim of minimizing exposure to animals or humans. Therefore, it is necessary to develop sensitive and inexpensive methods that can efficiently detect and monitor these pollutants in the environment. Conventional analytical techniques suffer from the disadvantages of high cost and complexity. Alternatively, prokaryotic or eukaryotic whole-cell biosensors (WCB) are one of the newest molecular tools employed in environmental monitoring that use the cell as an integrated reporter incorporating a reporter gene fused to a heavy metal responsive promoter. In the present paper, we report results from expressing, in the ciliate Tetrahymena thermophila, constructs consisting of the reporter gfp gene fused to the complete MTT1 or MTT5 protein coding regions under the transcriptional control of the MTT1 metallothionein promoter, which plays a critical role in heavy metal stress in this ciliate. When exposed to Cd(2+), such cells overexpress both the GFP reporter transgene and the linked metallothionein gene. We report that, for the GFPMTT5 strain, this metallothionein overexpression results in marked resistance to cadmium toxicity (24 h LC50 ~15 μM of Cd(2+)), compared to wild type cells (24 h LC50 ~1.73 μM of Cd(2+)). These results provide the first experimental evidence that ciliate metallothioneins, like in other organisms, function to protect the cell against toxic metal ions. Because these strains may have novel advantages as WCBs, we have compared their properties to those of other previously reported Tetrahymena WCBs.
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Affiliation(s)
- Francisco Amaro
- Departamento de Microbiología-III, Facultad de Biología, C/. José Antonio Novais 12, Universidad Complutense (UCM), 28040 Madrid, Spain
| | - Aaron P. Turkewitz
- Department of Molecular Genetics and Cell Biology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL. 60637, USA
| | - Ana Martín-González
- Departamento de Microbiología-III, Facultad de Biología, C/. José Antonio Novais 12, Universidad Complutense (UCM), 28040 Madrid, Spain
| | - Juan Carlos Gutiérrez
- Departamento de Microbiología-III, Facultad de Biología, C/. José Antonio Novais 12, Universidad Complutense (UCM), 28040 Madrid, Spain
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Cowan GJM, Bockau U, Eleni-Muus J, Aldag I, Samuel K, Creasey AM, Hartmann MWW, Cavanagh DR. A novel malaria vaccine candidate antigen expressed in Tetrahymena thermophila. PLoS One 2014; 9:e87198. [PMID: 24489871 PMCID: PMC3906136 DOI: 10.1371/journal.pone.0087198] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 12/20/2013] [Indexed: 01/15/2023] Open
Abstract
Development of effective malaria vaccines is hampered by the problem of producing correctly folded Plasmodium proteins for use as vaccine components. We have investigated the use of a novel ciliate expression system, Tetrahymena thermophila, as a P. falciparum vaccine antigen platform. A synthetic vaccine antigen composed of N-terminal and C-terminal regions of merozoite surface protein-1 (MSP-1) was expressed in Tetrahymena thermophila. The recombinant antigen was secreted into the culture medium and purified by monoclonal antibody (mAb) affinity chromatography. The vaccine was immunogenic in MF1 mice, eliciting high antibody titers against both N- and C-terminal components. Sera from immunized animals reacted strongly with P. falciparum parasites from three antigenically different strains by immunofluorescence assays, confirming that the antibodies produced are able to recognize parasite antigens in their native form. Epitope mapping of serum reactivity with a peptide library derived from all three MSP-1 Block 2 serotypes confirmed that the MSP-1 Block 2 hybrid component of the vaccine had effectively targeted all three serotypes of this polymorphic region of MSP-1. This study has successfully demonstrated the use of Tetrahymena thermophila as a recombinant protein expression platform for the production of malaria vaccine antigens.
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Affiliation(s)
- Graeme J. M. Cowan
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | | | - Kay Samuel
- Cell Therapy Group, Scottish National Blood Transfusion Service, Edinburgh, United Kingdom
| | - Alison M. Creasey
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | | | - David R. Cavanagh
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Mielke RE, Priester JH, Werlin RA, Gelb J, Horst AM, Orias E, Holden PA. Differential growth of and nanoscale TiO₂ accumulation in Tetrahymena thermophila by direct feeding versus trophic transfer from Pseudomonas aeruginosa. Appl Environ Microbiol 2013; 79:5616-24. [PMID: 23851096 PMCID: PMC3754167 DOI: 10.1128/aem.01680-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/03/2013] [Indexed: 11/20/2022] Open
Abstract
Nanoscale titanium dioxide (TiO2) is increasingly used in consumer goods and is entering waste streams, thereby exposing and potentially affecting environmental microbes. Protozoans could either take up TiO2 directly from water and sediments or acquire TiO2 during bactivory (ingestion of bacteria) of TiO2-encrusted bacteria. Here, the route of exposure of the ciliated protozoan Tetrahymena thermophila to TiO2 was varied and the growth of, and uptake and accumulation of TiO2 by, T. thermophila were measured. While TiO2 did not affect T. thermophila swimming or cellular morphology, direct TiO2 exposure in rich growth medium resulted in a lower population yield. When TiO2 exposure was by bactivory of Pseudomonas aeruginosa, the T. thermophila population yield and growth rate were lower than those that occurred during the bactivory of non-TiO2-encrusted bacteria. Regardless of the feeding mode, T. thermophila cells internalized TiO2 into their food vacuoles. Biomagnification of TiO2 was not observed; this was attributed to the observation that TiO2 appeared to be unable to cross the food vacuole membrane and enter the cytoplasm. Nevertheless, our findings imply that TiO2 could be transferred into higher trophic levels within food webs and that the food web could be affected by the decreased growth rate and yield of organisms near the base of the web.
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Affiliation(s)
- Randall E. Mielke
- Bren School of Environmental Science and Management, Earth Research Institute, and UC Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, California, USA
- Jet Propulsion Laboratory, California Institute of Technology—NASA, Planetary Science, Pasadena, California, USA
| | - John H. Priester
- Bren School of Environmental Science and Management, Earth Research Institute, and UC Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, California, USA
| | - Rebecca A. Werlin
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California, USA
| | - Jeff Gelb
- Xradia Corporation, Pleasanton, California, USA
| | - Allison M. Horst
- Bren School of Environmental Science and Management, Earth Research Institute, and UC Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, California, USA
| | - Eduardo Orias
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California, USA
| | - Patricia A. Holden
- Bren School of Environmental Science and Management, Earth Research Institute, and UC Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, California, USA
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Nakano T, Ohki I, Yokota A, Ashida H. MtnBD is a multifunctional fusion enzyme in the methionine salvage pathway of Tetrahymena thermophila. PLoS One 2013; 8:e67385. [PMID: 23840871 PMCID: PMC3698126 DOI: 10.1371/journal.pone.0067385] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 05/17/2013] [Indexed: 11/19/2022] Open
Abstract
To recycle reduced sulfur to methionine in the methionine salvage pathway (MSP), 5-methylthioribulose-1-phosphate is converted to 2-keto-4-methylthiobutyrate, the methionine precursor, by four steps; dehydratase, enolase, phosphatase, and dioxygenase reactions (catalyzed by MtnB, MtnW, MtnX and MtnD, respectively, in Bacillus subtilis). It has been proposed that the MtnBD fusion enzyme in Tetrahymena thermophila catalyzes four sequential reactions from the dehydratase to dioxygenase steps, based on the results of molecular biological analyses of mutant yeast strains with knocked-out MSP genes, suggesting that new catalytic function can be acquired by fusion of enzymes. This result raises the question of how the MtnBD fusion enzyme can catalyze four very different reactions, especially since there are no homologous domains for enolase and phosphatase (MtnW and MtnX, respectively, in B. subtilis) in the peptide. Here, we tried to identify the domains responsible for catalyzing the four reactions using recombinant proteins of full-length MtnBD and each domain alone. UV-visible and ¹H-NMR spectral analyses of reaction products revealed that the MtnB domain catalyzes dehydration and enolization and the MtnD domain catalyzes dioxygenation. Contrary to a previous report, conversion of 5-methylthioribulose-1-phosphate to 2-keto-4-methylthiobutyrate was dependent on addition of an exogenous phosphatase from B. subtilis. This was observed for both the MtnB domain and full-length MtnBD, suggesting that MtnBD does not catalyze the phosphatase reaction. Our results suggest that the MtnB domain of T. thermophila MtnBD acquired the new function to catalyze both the dehydratase and enolase reactions through evolutionary gene mutations, rather than fusion of MSP genes.
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Affiliation(s)
- Toshihiro Nakano
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, Nara, Japan
| | - Izuru Ohki
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, Nara, Japan
| | - Akiho Yokota
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, Nara, Japan
| | - Hiroki Ashida
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, Nara, Japan
- Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Kawaguchi, Saitama, Japan
- * E-mail:
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Abstract
The ciliate Tetrahymena thermophila is an excellent model system for the discovery and functional studies of ciliary proteins. The power of the model is based on the ease with which cilia can be purified in large quantities for fractionation and proteomic identification, and the ability to knock out any gene by homologous DNA recombination. Here, we include methods used by our laboratories for isolation and fractionation of cilia, in vivo tagging and localization of ciliary proteins, and the evaluation of ciliary mutants.
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Affiliation(s)
- Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA 30605, USA
| | - Dorota Wloga
- Nencki Institute of Experimental Biology, Polish Academy of Science, 02-093 Warsaw, Poland
| | | | - Mayukh Guha
- Department of Cellular Biology, University of Georgia, Athens, GA 30605, USA
| | - William Dentler
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
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Xu J, Tian H, Wang W, Liang A. The zinc finger protein Zfr1p is localized specifically to conjugation junction and required for sexual development in Tetrahymena thermophila. PLoS One 2012; 7:e52799. [PMID: 23251712 PMCID: PMC3519685 DOI: 10.1371/journal.pone.0052799] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 11/21/2012] [Indexed: 11/19/2022] Open
Abstract
Conjugation in Tetrahymena thermophila involves a developmental program consisting of three prezygotic nuclear divisions, pronuclear exchange and fusion, and postzygotic and exconjugant stages. The conjugation junction structure appears during the initiation of conjugation development, and disappears during the exconjugant stage. Many structural and functional proteins are involved in the establishment and maintenance of the junction structure in T. thermophila. In the present study, a zinc finger protein-encoding gene ZFR1 was found to be expressed specifically during conjugation and to localize specifically to the conjugation junction region. Truncated Zfr1p localized at the plasma membrane in ordered arrays and decorated Golgi apparatus located adjacent to basal body. The N-terminal zinc finger and C-terminal hydrophobic domains of Zfr1p were found to be required for its specific conjugation junction localization. Conjugation development of ZFR1 somatic knockout cells was aborted at the pronuclear exchange and fusion conjugation stages. Furthermore, Zfr1p was found to be important for conjugation junction stability during the prezygotic nuclear division stage. Taken together, our data reveal that Zfr1p is required for the stability and integrity of the conjugation junction structure and essential for the sexual life cycle of the Tetrahymena cell.
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Affiliation(s)
- Jing Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Huaru Tian
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Aihua Liang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
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Bayless BA, Giddings TH, Winey M, Pearson CG. Bld10/Cep135 stabilizes basal bodies to resist cilia-generated forces. Mol Biol Cell 2012; 23:4820-32. [PMID: 23115304 PMCID: PMC3521689 DOI: 10.1091/mbc.e12-08-0577] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 10/18/2012] [Accepted: 10/23/2012] [Indexed: 12/03/2022] Open
Abstract
Basal bodies nucleate, anchor, and organize cilia. As the anchor for motile cilia, basal bodies must be resistant to the forces directed toward the cell as a consequence of ciliary beating. The molecules and generalized mechanisms that contribute to the maintenance of basal bodies remain to be discovered. Bld10/Cep135 is a basal body outer cartwheel domain protein that has established roles in the assembly of nascent basal bodies. We find that Bld10 protein first incorporates stably at basal bodies early during new assembly. Bld10 protein continues to accumulate at basal bodies after assembly, and we hypothesize that the full complement of Bld10 is required to stabilize basal bodies. We identify a novel mechanism for Bld10/Cep135 in basal body maintenance so that basal bodies can withstand the forces produced by motile cilia. Bld10 stabilizes basal bodies by promoting the stability of the A- and C-tubules of the basal body triplet microtubules and by properly positioning the triplet microtubule blades. The forces generated by ciliary beating promote basal body disassembly in bld10Δ cells. Thus Bld10/Cep135 acts to maintain the structural integrity of basal bodies against the forces of ciliary beating in addition to its separable role in basal body assembly.
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Affiliation(s)
- Brian A. Bayless
- Department of Cell and Developmental Biology, University of Colorado Denver–Anshutz Medical Campus, Aurora, CO 80045-2537
| | - Thomas H. Giddings
- Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309-0347
| | - Mark Winey
- Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309-0347
| | - Chad G. Pearson
- Department of Cell and Developmental Biology, University of Colorado Denver–Anshutz Medical Campus, Aurora, CO 80045-2537
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Abstract
Two types dopamine receptor present in the cell membrane of vertebrates. But in this study D1 receptor was identified in the invertebrate ciliates protozoan, Tetrahymena thermophila by use of fluorescent ligands. D1 specific agonist SKF-38393 binds specifically to Tetrahymena. The specific binding of SKF-38393 was encountered by equimolar addition of D1 antagonist thus showed no binding of ligands. In addition, it was also proved that the D1 specific agonist did not cross bind with the D2 type receptor due to the equimolar addition of D2 selective antagonist spiperone. Interestingly this study also showed that the dopamine receptor present in the endoplasmic reticulum and endosomes of Tetrahymena as well as cell membrane which was revealed by laser scanning microscope. Therefore, this evidence supports the existence of a D1 receptor in the ciliate protozoan.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/analogs & derivatives
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/metabolism
- Benzazepines/metabolism
- Dopamine Agonists/metabolism
- Dopamine Antagonists/metabolism
- Fluorescent Dyes/metabolism
- Ligands
- Microscopy, Confocal
- Microscopy, Fluorescence
- Protozoan Proteins/metabolism
- Receptors, Dopamine D1/metabolism
- Rhodamines/metabolism
- Spiperone/analogs & derivatives
- Spiperone/metabolism
- Tetrahymena thermophila/metabolism
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Affiliation(s)
- Asad Ud-Daula
- Helmholtz Zentrum Miinchen, German Research Center for Environmental Health, Institute of Ecological Chemistry, Ingolstiidter Landstrasse 1, D-85764 Neuherberg, Germany
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Lin YC, Perevedentseva E, Tsai LW, Wu KT, Cheng CL. Nanodiamond for intracellular imaging in the microorganisms in vivo. J Biophotonics 2012; 5:838-847. [PMID: 22815227 DOI: 10.1002/jbio.201200088] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 06/18/2012] [Accepted: 06/19/2012] [Indexed: 06/01/2023]
Abstract
Nanodiamond (ND) has great potential for bio labeling and drug delivery. In this work, the biocompatibility and bio labeling of ND are demonstrated via the interaction with cells and microorganisms, protists microorganisms Paramecium caudatum and Tetrahymena thermophile, in vitro and in vivo. We found the microorganism's living functions are not significantly affected by ND. The NDs were found entering the food vacuoles and later excreted by the microorganisms. The 5 nm ND was found more toxic compared to 100 nm ND, presumably due to the surface disordered carbons. Our results demonstrated nanodiamond can be used in bio imaging and matter delivery.
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Affiliation(s)
- Yu-Chung Lin
- Department of Physics, National Dong Hwa University, Hualien, Taiwan
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Talsky KB, Collins K. Strand-asymmetric endogenous Tetrahymena small RNA production requires a previously uncharacterized uridylyltransferase protein partner. RNA 2012; 18:1553-1562. [PMID: 22706992 PMCID: PMC3404375 DOI: 10.1261/rna.033530.112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 05/22/2012] [Indexed: 06/01/2023]
Abstract
Many eukaryotes initiate pathways of Argonaute-bound small RNA (sRNA) production with a step that specifically targets sets of aberrant and/or otherwise deleterious transcripts for recognition by an RNA-dependent RNA polymerase complex (RDRC). The biogenesis of 23- to 24-nt sRNAs in growing Tetrahymena occurs by physical and functional coupling of the growth-expressed Dicer, Dcr2, with one of three RDRCs each containing the single genome-encoded RNA-dependent RNA polymerase, Rdr1. Tetrahymena RDRCs contain an active uridylyltransferase, either Rdn1 or Rdn2, and Rdn1 RDRCs also contain the Rdf1 and Rdf2 proteins. Although Rdn2 is nonessential and RDRC-specific, Rdn1 is genetically essential and interacts with a non-RDRC protein of 124 kDa. Here we characterize this 124-kDa protein, designated RNA silencing protein 1 (Rsp1), using endogenous locus tagging, affinity purification, and functional assays, as well as gene-knockout studies. We find that Rsp1 associates with Rdn1-Rdf1 or Rdn1-Rdf2 subcomplexes as an alternative to Rdr1, creating Rsp1 complexes (RSPCs) that are physically separate from RDRCs. The uridylyltransferase activity of Rdn1 is greatly reduced in RSPCs compared with RDRCs, suggesting enzyme regulation by the alternative partners. Surprisingly, despite the loss of all known RDRC-generated classes of endogenous sRNAs, RSP1 gene knockout was tolerated in growing cells. A minority class of Dcr2-dependent sRNAs persists in cells lacking Rsp1 with increased size heterogeneity. These findings bring new insights about the essential and nonessential functions of RNA silencing in Tetrahymena, about mechanisms of endogenous small interfering RNA production, and about the roles of cellular uridylyltransferases.
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Affiliation(s)
- Kristin Benjamin Talsky
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3200, USA.
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Rajapakse K, Drobne D, Valant J, Vodovnik M, Levart A, Marinsek-Logar R. Acclimation of Tetrahymena thermophila to bulk and nano-TiO2 particles by changes in membrane fatty acids saturation. J Hazard Mater 2012; 221-222:199-205. [PMID: 22551634 DOI: 10.1016/j.jhazmat.2012.04.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 03/31/2012] [Accepted: 04/13/2012] [Indexed: 05/31/2023]
Abstract
We provide experimental evidence that changes in the membrane fatty acid profile of Tetrahymena thermophila incubated with nano- or bulk TiO(2) particle are not accompanied by ROS generation or lipid peroxidation. Consequently these changes are interpreted as acclimation to unfavorable conditions and not as toxic effects. T. thermophila cells were exposed to TiO(2) particles at different concentrations for 24h at 32°C. Treatment of cultures with nano- and bulk TiO(2) particles resulted in changes of membrane fatty acid profile, indicating increased membrane rigidity, but no lipid peroxidation or ROS generation was detected. There were no differences in membrane composition when T. thermophila was exposed to nanosized or bulk-TiO(2) particles. We also observed reversible filling of food vacuoles, but this was different in case of nano- or bulk TiO(2) exposure. Our results suggest that interactions of particles and cell membranes are independent of oxidative stress.
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Affiliation(s)
- K Rajapakse
- Department of Animal Sciences, University of Ljubljana, Groblje 3, SI-1230 Domzale, Slovenia.
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Song X, Bowen J, Miao W, Liu Y, Gorovsky MA. The nonhistone, N-terminal tail of an essential, chimeric H2A variant regulates mitotic H3-S10 dephosphorylation. Genes Dev 2012; 26:615-29. [PMID: 22426537 PMCID: PMC3315122 DOI: 10.1101/gad.182683.111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Accepted: 02/06/2012] [Indexed: 12/21/2022]
Abstract
H2A.Y is an essential, divergent Tetrahymena thermophila histone variant. It has a long nonhistone N terminus that contains leucine-rich repeats (LRR) and an LRR cap domain with similarity to Sds22p, a regulator of yeast protein phosphatase 1 (PP1) activity in the nucleus. In growing cells, H2A.Y is incorporated into micronuclei only during S phase, which occurs immediately after micronuclear mitosis. Depletion of H2A.Y causes prolonged retention of mitosis-associated histone H3-S10 phosphorylation and mitotic abnormalities that mimic S10E mutation. In cells where H2A.Y is depleted, an inducible chimeric gene, in which the H2A.Y N terminus is attached to H2A.X, is shown to regulate micronuclear H3-S10 phosphorylation. H2A.Y can also be specifically coimmunoprecipitated with a Tetrahymena PP1 ortholog (Ppo1p). Taken together, these results argue that the N terminus of H2A.Y functions to regulate H3-S10 dephosphorylation. This striking in vivo case of "cross-talk" between a H2A variant and a specific post-translational modification of another histone demonstrates a novel function for a histone variant.
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Affiliation(s)
- Xiaoyuan Song
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
| | - Josephine Bowen
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
| | - Wei Miao
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
| | - Yifan Liu
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
| | - Martin A. Gorovsky
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
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Lu XY, Xiong J, Yuan DX, Miao W. [Alternative splicing of an ATP-binding cassette transporter ABCC10 in Tetrahymena thermophila]. Dongwuxue Yanjiu 2011; 32:605-610. [PMID: 22184018 DOI: 10.3724/sp.j.1141.2011.06605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
ATP-binding cassette transporters (ABCT) could generate multiple transcripts through alternative splicing (AS) in mammalian. Some AS introduced PTC (premature terminal codon)-containing isoforms of ABCT couple with NMD (nonsense-mediated mRNA decay) to regulate relevant functions. However, there are no similar reports in lower organisms. This paper focuses on the unicellular protozoa Tetrahymena thermophila, based on the RNA-seq data of Tetrahymena thermophila, identified two alternative splicing variants of gene ABCC10 (SV1 and SV2). The SV2 contained an intron retention event at the fifth intron, and this 49 bp intron resulted in shift-frame and introduced PTC. Then, a knock-down Tetrahymena strain of gene UPF1 which is a key factor of NMD was constructed, and the expression levels of SV2 were performed using a real-time quantitative PCR. The results showed the expression levels of SV2 were up-regulated significantly in knock-down strain, indicating that SV2 was targeted by NMD, which is consistent to the mechanism which the AS introduced PTC-containing isoforms of ABCC proteins can be targeted by NMD in mammalian. Thus, we infer that this mechanism is highly evolutionary conserved in eukaryotes and was already functional in the last eukaryotic common ancestor.
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Affiliation(s)
- Xing-Yi Lu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, the Chinese Academy of Science, Wuhan 430072, China
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