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Khomutov MA, Salikhov AI, Mitkevich VA, Tunitskaya VL, Smirnova OA, Korolev SP, Chizhov AO, Gottikh MB, Kochetkov SN, Khomutov AR. C-Methylated Spermidine Derivatives: Convenient Syntheses and Antizyme-Related Effects. Biomolecules 2023; 13:916. [PMID: 37371496 DOI: 10.3390/biom13060916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/25/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023] Open
Abstract
The biogenic polyamines, spermidine (Spd) and spermine (Spm), are present at millimolar concentrations in all eukaryotic cells, where they participate in the regulation of vitally important cellular functions. Polyamine analogs and derivatives are a traditional and important instrument for the investigation of the cellular functions of polyamines, enzymes of their metabolism, and the regulation of the biosynthesis of antizyme-a key downregulator of polyamine homeostasis. Here, we describe convenient gram-scale syntheses of a set of C-methylated analogs of Spd. The biochemical properties of these compounds and the possibility for the regulation of their activity by moving a methyl group along the polyamine backbone and by changing the stereochemistry of the chiral center(s) are discussed.
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Affiliation(s)
- Maxim A Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Arthur I Salikhov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Vladimir A Mitkevich
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Vera L Tunitskaya
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Olga A Smirnova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Sergey P Korolev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Alexander O Chizhov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninskii Prosp. 47, Moscow 119991, Russia
| | - Marina B Gottikh
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Sergey N Kochetkov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
| | - Alex R Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow 119991, Russia
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2
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Rehfeld F, Eitson JL, Ohlson MB, Chang TC, Schoggins JW, Mendell JT. CRISPR screening reveals a dependency on ribosome recycling for efficient SARS-CoV-2 programmed ribosomal frameshifting and viral replication. Cell Rep 2023; 42:112076. [PMID: 36753415 PMCID: PMC9884621 DOI: 10.1016/j.celrep.2023.112076] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 11/21/2022] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
During translation of the genomic RNA of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative virus in the COVID-19 pandemic, host ribosomes undergo programmed ribosomal frameshifting (PRF) at a conserved structural element. Although PRF is essential for coronavirus replication, host factors that regulate this process have not yet been identified. Here we perform genome-wide CRISPR-Cas9 knockout screens to identify regulators of SARS-CoV-2 PRF. These screens reveal that loss of ribosome recycling factors markedly decreases frameshifting efficiency and impairs SARS-CoV-2 viral replication. Mutational studies support a model wherein efficient removal of ribosomal subunits at the ORF1a stop codon is required for frameshifting of trailing ribosomes. This dependency upon ribosome recycling is not observed with other non-pathogenic human betacoronaviruses and is likely due to the unique position of the ORF1a stop codon in the SARS clade of coronaviruses. These findings therefore uncover host factors that support efficient SARS-CoV-2 translation and replication.
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Affiliation(s)
- Frederick Rehfeld
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jennifer L Eitson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Maikke B Ohlson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Tsung-Cheng Chang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - John W Schoggins
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Joshua T Mendell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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3
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Mikl M, Pilpel Y, Segal E. High-throughput interrogation of programmed ribosomal frameshifting in human cells. Nat Commun 2020; 11:3061. [PMID: 32546731 PMCID: PMC7297798 DOI: 10.1038/s41467-020-16961-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/28/2020] [Indexed: 12/30/2022] Open
Abstract
Programmed ribosomal frameshifting (PRF) is the controlled slippage of the translating ribosome to an alternative frame. This process is widely employed by human viruses such as HIV and SARS coronavirus and is critical for their replication. Here, we developed a high-throughput approach to assess the frameshifting potential of a sequence. We designed and tested >12,000 sequences based on 15 viral and human PRF events, allowing us to systematically dissect the rules governing ribosomal frameshifting and discover novel regulatory inputs based on amino acid properties and tRNA availability. We assessed the natural variation in HIV gag-pol frameshifting rates by testing >500 clinical isolates and identified subtype-specific differences and associations between viral load in patients and the optimality of PRF rates. We devised computational models that accurately predict frameshifting potential and frameshifting rates, including subtle differences between HIV isolates. This approach can contribute to the development of antiviral agents targeting PRF.
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Affiliation(s)
- Martin Mikl
- Department of Computer Science and Applied Mathematics, Rehovot, 7610001, Israel.
- Department of Molecular Cell Biology and Weizmann Institute of Science, Rehovot, 7610001, Israel.
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Mount Carmel, Haifa, 31905, Israel.
| | - Yitzhak Pilpel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Eran Segal
- Department of Computer Science and Applied Mathematics, Rehovot, 7610001, Israel.
- Department of Molecular Cell Biology and Weizmann Institute of Science, Rehovot, 7610001, Israel.
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4
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Poidevin L, Unal D, Belda-Palazón B, Ferrando A. Polyamines as Quality Control Metabolites Operating at the Post-Transcriptional Level. PLANTS 2019; 8:plants8040109. [PMID: 31022874 PMCID: PMC6524035 DOI: 10.3390/plants8040109] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 04/17/2019] [Accepted: 04/19/2019] [Indexed: 01/04/2023]
Abstract
Plant polyamines (PAs) have been assigned a large number of physiological functions with unknown molecular mechanisms in many cases. Among the most abundant and studied polyamines, two of them, namely spermidine (Spd) and thermospermine (Tspm), share some molecular functions related to quality control pathways for tightly regulated mRNAs at the level of translation. In this review, we focus on the roles of Tspm and Spd to facilitate the translation of mRNAs containing upstream ORFs (uORFs), premature stop codons, and ribosome stalling sequences that may block translation, thus preventing their degradation by quality control mechanisms such as the nonsense-mediated decay pathway and possible interactions with other mRNA quality surveillance pathways.
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Affiliation(s)
- Laetitia Poidevin
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, 46022 Valencia, Spain.
| | - Dilek Unal
- Biotechnology Application and Research Center, and Department of Molecular Biology, Faculty of Science and Letter, Bilecik Seyh Edebali University, 11230 Bilecik, Turkey.
| | - Borja Belda-Palazón
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, 46022 Valencia, Spain.
| | - Alejandro Ferrando
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, 46022 Valencia, Spain.
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5
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Abstract
The polyamines spermidine, spermine, and their precursor putrescine are organic polycations involved in various cellular processes and are absolutely essential for cellular proliferation. Because of their crucial function in the cell, their intracellular concentration must be maintained at optimal levels. To a large extent, this regulation is achieved through the activity of an autoregulatory loop that involves two proteins, antizyme (Az) and antizyme inhibitor (AzI), that regulate the first enzyme in polyamine biosynthesis, ornithine decarboxylase (ODC), and polyamine uptake activity in response to intracellular polyamine levels. In this Minireview, I will discuss what has been learned about the mechanism of Az expression and its physical interaction with both ODC and AzI in the regulation of polyamines.
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Affiliation(s)
- Chaim Kahana
- From the Department of Molecular Genetics, the Weizmann Institute of Science, Rehovot 76100, Israel
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6
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Abstract
Polyamines are organic polycations that bind to a variety of cellular molecules, including nucleic acids. Within cells, polyamines contribute to both the efficiency and fidelity of protein synthesis. In addition to directly acting on the translation apparatus to stimulate protein synthesis, the polyamine spermidine serves as a precursor for the essential post-translational modification of the eukaryotic translation factor 5A (eIF5A), which is required for synthesis of proteins containing problematic amino acid sequence motifs, including polyproline tracts, and for termination of translation. The impact of polyamines on translation is highlighted by autoregulation of the translation of mRNAs encoding key metabolic and regulatory proteins in the polyamine biosynthesis pathway, including S-adenosylmethionine decarboxylase (AdoMetDC), antizyme (OAZ), and antizyme inhibitor 1 (AZIN1). Here, we highlight the roles of polyamines in general translation and also in the translational regulation of polyamine biosynthesis.
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Affiliation(s)
- Thomas E Dever
- From the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Ivaylo P Ivanov
- From the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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7
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Gevrekci AÖ. The roles of polyamines in microorganisms. World J Microbiol Biotechnol 2017; 33:204. [PMID: 29080149 DOI: 10.1007/s11274-017-2370-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/15/2017] [Indexed: 10/18/2022]
Abstract
Polyamines are small polycations that are well conserved in all the living organisms except Archae, Methanobacteriales and Halobacteriales. The most common polyamines are putrescine, spermidine and spermine, which exist in varying concentrations in different organisms. They are involved in a variety of cellular processes such as gene expression, cell growth, survival, stress response and proliferation. Therefore, diverse regulatory pathways are evolved to ensure strict regulation of polyamine concentration in the cells. Polyamine levels are kept under strict control by biosynthetic pathways as well as cellular uptake driven by specific transporters. Reverse genetic studies in microorganisms showed that deletion of the genes in polyamine metabolic pathways or depletion of polyamines have negative effects on cell survival and proliferation. The protein products of these genes are also used as drug targets against pathogenic protozoa. These altogether confirm the significant roles of polyamines in the cells. This mini-review focuses on the differential concentrations of polyamines and their cellular functions in different microorganisms. This will provide an insight about the diverse evolution of polyamine metabolism and function based on the physiology and the ecological context of the microorganisms.
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Affiliation(s)
- Aslıhan Örs Gevrekci
- Department of Psychology, Faculty of Science and Letters, Başkent University, Ankara, Turkey.
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Dinan AM, Atkins JF, Firth AE. ASXL gain-of-function truncation mutants: defective and dysregulated forms of a natural ribosomal frameshifting product? Biol Direct 2017; 12:24. [PMID: 29037253 PMCID: PMC5644247 DOI: 10.1186/s13062-017-0195-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 10/04/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Programmed ribosomal frameshifting (PRF) is a gene expression mechanism which enables the translation of two N-terminally coincident, C-terminally distinct protein products from a single mRNA. Many viruses utilize PRF to control or regulate gene expression, but very few phylogenetically conserved examples are known in vertebrate genes. Additional sex combs-like (ASXL) genes 1 and 2 encode important epigenetic and transcriptional regulatory proteins that control the expression of homeotic genes during key developmental stages. Here we describe an ~150-codon overlapping ORF (termed TF) in ASXL1 and ASXL2 that, with few exceptions, is conserved throughout vertebrates. RESULTS Conservation of the TF ORF, strong suppression of synonymous site variation in the overlap region, and the completely conserved presence of an EH[N/S]Y motif (a known binding site for Host Cell Factor-1, HCF-1, an epigenetic regulatory factor), all indicate that TF is a protein-coding sequence. A highly conserved UCC_UUU_CGU sequence (identical to the known site of +1 ribosomal frameshifting for influenza virus PA-X expression) occurs at the 5' end of the region of enhanced synonymous site conservation in ASXL1. Similarly, a highly conserved RG_GUC_UCU sequence (identical to a known site of -2 ribosomal frameshifting for arterivirus nsp2TF expression) occurs at the 5' end of the region of enhanced synonymous site conservation in ASXL2. CONCLUSIONS Due to a lack of appropriate splice forms, or initiation sites, the most plausible mechanism for translation of the ASXL1 and 2 TF regions is ribosomal frameshifting, resulting in a transframe fusion of the N-terminal half of ASXL1 or 2 to the TF product, termed ASXL-TF. Truncation or frameshift mutants of ASXL are linked to myeloid malignancies and genetic diseases, such as Bohring-Opitz syndrome, likely at least in part as a result of gain-of-function or dominant-negative effects. Our hypothesis now indicates that these disease-associated mutant forms represent overexpressed defective versions of ASXL-TF. REVIEWERS This article was reviewed by Laurence Hurst and Eugene Koonin.
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Affiliation(s)
- Adam M Dinan
- Department of Pathology, Division of Virology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, T12 YT57, Cork, Ireland.,Department of Human Genetics, University of Utah, Salt Lake City, UT, 84112, USA
| | - Andrew E Firth
- Department of Pathology, Division of Virology, University of Cambridge, Cambridge, CB2 1QP, UK.
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9
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Gevrekci AÖ. Fission Yeast srm1 is Involved in Stress Response and Cell Cycle. Curr Microbiol 2017; 74:725-731. [PMID: 28345120 DOI: 10.1007/s00284-017-1241-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 03/21/2017] [Indexed: 10/19/2022]
Abstract
Polyamines are well-conserved, multifunctional polycations that contribute to a number of processes in the cells such as cell cycle, apoptosis, stress response, and gene expression. Therefore, polyamine levels should be kept under strict regulation by specific polyamine transporters and polyamine synthases. In this study, the aim is to experimentally characterize a predicted spermidine synthase gene srm1, which was identified upon sequence similarity, in fission yeast Schizosaccharomyces pombe. In an attempt to understand the role of this gene in cell cycle and stress response, deletion mutant of srm1 was generated and analyzed in terms of cell cycle regulation and environmental stress response. The results showed that srm1Δ cells had elongated cell size and were sensitive to osmotic stress, while they showed no sensitivity to DNA-damaging agents. To the best of our knowledge, this is the first experimental characterization of srm1 gene and its role in cell cycle progression and stress response.
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Affiliation(s)
- Aslıhan Örs Gevrekci
- Department of Psychology, Faculty of Science and Letters, Başkent University, Ankara, Turkey.
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10
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Atkins JF, Loughran G, Bhatt PR, Firth AE, Baranov PV. Ribosomal frameshifting and transcriptional slippage: From genetic steganography and cryptography to adventitious use. Nucleic Acids Res 2016; 44:7007-78. [PMID: 27436286 PMCID: PMC5009743 DOI: 10.1093/nar/gkw530] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/26/2016] [Indexed: 12/15/2022] Open
Abstract
Genetic decoding is not ‘frozen’ as was earlier thought, but dynamic. One facet of this is frameshifting that often results in synthesis of a C-terminal region encoded by a new frame. Ribosomal frameshifting is utilized for the synthesis of additional products, for regulatory purposes and for translational ‘correction’ of problem or ‘savior’ indels. Utilization for synthesis of additional products occurs prominently in the decoding of mobile chromosomal element and viral genomes. One class of regulatory frameshifting of stable chromosomal genes governs cellular polyamine levels from yeasts to humans. In many cases of productively utilized frameshifting, the proportion of ribosomes that frameshift at a shift-prone site is enhanced by specific nascent peptide or mRNA context features. Such mRNA signals, which can be 5′ or 3′ of the shift site or both, can act by pairing with ribosomal RNA or as stem loops or pseudoknots even with one component being 4 kb 3′ from the shift site. Transcriptional realignment at slippage-prone sequences also generates productively utilized products encoded trans-frame with respect to the genomic sequence. This too can be enhanced by nucleic acid structure. Together with dynamic codon redefinition, frameshifting is one of the forms of recoding that enriches gene expression.
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Affiliation(s)
- John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland School of Microbiology, University College Cork, Cork, Ireland Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Pramod R Bhatt
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
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11
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Wang R, Xiong J, Wang W, Miao W, Liang A. High frequency of +1 programmed ribosomal frameshifting in Euplotes octocarinatus. Sci Rep 2016; 6:21139. [PMID: 26891713 PMCID: PMC4759687 DOI: 10.1038/srep21139] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/18/2016] [Indexed: 01/25/2023] Open
Abstract
Programmed -1 ribosomal frameshifting (-1 PRF) has been identified as a mechanism to regulate the expression of many viral genes and some cellular genes. The slippery site of -1 PRF has been well characterized, whereas the +1 PRF signal and the mechanism involved in +1 PRF remain poorly understood. Previous study confirmed that +1 PRF is required for the synthesis of protein products in several genes of ciliates from the genus Euplotes. To accurately assess the frequency of genes requiring frameshift in Euplotes, the macronuclear genome and transcriptome of Euplotes octocarinatus were analyzed in this study. A total of 3,700 +1 PRF candidate genes were identified from 32,353 transcripts, and the gene products of these putative +1 PRFs were mainly identified as protein kinases. Furthermore, we reported a putative suppressor tRNA of UAA which may provide new insights into the mechanism of +1 PRF in euplotids. For the first time, our transcriptome-wide survey of +1 PRF in E. octocarinatus provided a dataset which serves as a valuable resource for the future understanding of the mechanism underlying +1 PRF.
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Affiliation(s)
- Ruanlin Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | - Jie Xiong
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | - Wei Miao
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Aihua Liang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
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12
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Tong W, Imai A, Tabata R, Shigenobu S, Yamaguchi K, Yamada M, Hasebe M, Sawa S, Motose H, Takahashi T. Polyamine Resistance Is Increased by Mutations in a Nitrate Transporter Gene NRT1.3 (AtNPF6.4) in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2016; 7:834. [PMID: 27379127 PMCID: PMC4904021 DOI: 10.3389/fpls.2016.00834] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/27/2016] [Indexed: 05/19/2023]
Abstract
Polyamines are small basic compounds present in all living organisms and act in a variety of biological processes. However, the mechanism of polyamine sensing, signaling and response in relation to other metabolic pathways remains to be fully addressed in plant cells. As one approach, we isolated Arabidopsis mutants that show increased resistance to spermine in terms of chlorosis. We show here that two of the mutants have a point mutation in a nitrate transporter gene of the NRT1/PTR family (NPF), NRT1.3 (AtNPF6.4). These mutants also exhibit increased resistance to putrescine and spermidine while loss-of-function mutants of the two closest homologs of NRT1.3, root-specific NRT1.1 (AtNPF6.3) and petiole-specific NRT1.4 (AtNPF6.2), were shown to have a normal sensitivity to polyamines. When the GUS reporter gene was expressed under the control of the NRT1.3 promoter, GUS staining was observed in leaf mesophyll cells and stem cortex cells but not in the epidermis, suggesting that NRT1.3 specifically functions in parenchymal tissues. We further found that the aerial part of the mutant seedling has normal levels of polyamines but shows reduced uptake of norspermidine compared with the wild type. These results suggest that polyamine transport or metabolism is associated with nitrate transport in the parenchymal tissue of the shoot.
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Affiliation(s)
- Wurina Tong
- Graduate School of Natural Science and Technology, Okayama UniversityOkayama, Japan
| | - Akihiro Imai
- National Institute for Basic BiologyOkazaki, Japan
| | - Ryo Tabata
- Graduate School of Science and Technology, Kumamoto UniversityKumamoto, Japan
| | | | | | - Masashi Yamada
- National Institute for Basic BiologyOkazaki, Japan
- Department of Biology, Duke UniversityDurham, NC, USA
| | | | - Shinichiro Sawa
- Graduate School of Science and Technology, Kumamoto UniversityKumamoto, Japan
| | - Hiroyasu Motose
- Graduate School of Natural Science and Technology, Okayama UniversityOkayama, Japan
| | - Taku Takahashi
- Graduate School of Natural Science and Technology, Okayama UniversityOkayama, Japan
- *Correspondence: Taku Takahashi,
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13
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Stegehake D, Kurosinski MA, Schürmann S, Daniel J, Lüersen K, Liebau E. Polyamine-independent Expression of Caenorhabditis elegans Antizyme. J Biol Chem 2015; 290:18090-18101. [PMID: 26032421 DOI: 10.1074/jbc.m115.644385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Indexed: 11/06/2022] Open
Abstract
Degradation of ornithine decarboxylase, the rate-limiting enzyme of polyamine biosynthesis, is promoted by the protein antizyme. Expression of antizyme is positively regulated by rising polyamine concentrations that induce a +1 translational frameshift required for production of the full-length protein. Antizyme itself is negatively regulated by the antizyme inhibitor. In our study, the regulation of Caenorhabditis elegans antizyme was investigated, and the antizyme inhibitor was identified. By applying a novel GFP-based method to monitor antizyme frameshifting in vivo, we show that the induction of translational frameshifting also occurs under stressful conditions. Interestingly, during starvation, the initiation of frameshifting was independent of polyamine concentrations. Because frameshifting was also prevalent in a polyamine auxotroph double mutant, a polyamine-independent regulation of antizyme frameshifting is suggested. Polyamine-independent induction of antizyme expression was found to be negatively regulated by the peptide transporter PEPT-1, as well as the target of rapamycin, but not by the daf-2 insulin signaling pathway. Stress-dependent expression of C. elegans antizyme occurred morely slowly than expression in response to increased polyamine levels, pointing to a more general reaction to unfavorable conditions and a diversion away from proliferation and reproduction toward conservation of energy. Interestingly, antizyme expression was found to drastically increase in aging individuals in a postreproductive manner. Although knockdown of antizyme did not affect the lifespan of C. elegans, knockdown of the antizyme inhibitor led to a significant reduction in lifespan. This is most likely caused by an increase in antizyme-mediated degradation of ornithine decarboxylase-1 and a resulting reduction in cellular polyamine levels.
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Affiliation(s)
- Dirk Stegehake
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Marc-André Kurosinski
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Sabine Schürmann
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Jens Daniel
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Kai Lüersen
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany
| | - Eva Liebau
- Department of Molecular Physiology, Institute for Animal Physiology, University of Muenster, 48143 Muenster, Germany.
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14
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Yordanova MM, Wu C, Andreev DE, Sachs MS, Atkins JF. A Nascent Peptide Signal Responsive to Endogenous Levels of Polyamines Acts to Stimulate Regulatory Frameshifting on Antizyme mRNA. J Biol Chem 2015; 290:17863-17878. [PMID: 25998126 PMCID: PMC4505036 DOI: 10.1074/jbc.m115.647065] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Indexed: 01/06/2023] Open
Abstract
The protein antizyme is a negative regulator of cellular polyamine concentrations from yeast to mammals. Synthesis of functional antizyme requires programmed +1 ribosomal frameshifting at the 3′ end of the first of two partially overlapping ORFs. The frameshift is the sensor and effector in an autoregulatory circuit. Except for Saccharomyces cerevisiae antizyme mRNA, the frameshift site alone only supports low levels of frameshifting. The high levels usually observed depend on the presence of cis-acting stimulatory elements located 5′ and 3′ of the frameshift site. Antizyme genes from different evolutionary branches have evolved different stimulatory elements. Prior and new multiple alignments of fungal antizyme mRNA sequences from the Agaricomycetes class of Basidiomycota show a distinct pattern of conservation 5′ of the frameshift site consistent with a function at the amino acid level. As shown here when tested in Schizosaccharomyces pombe and mammalian HEK293T cells, the 5′ part of this conserved sequence acts at the nascent peptide level to stimulate the frameshifting, without involving stalling detectable by toe-printing. However, the peptide is only part of the signal. The 3′ part of the stimulator functions largely independently and acts at least mostly at the nucleotide level. When polyamine levels were varied, the stimulatory effect was seen to be especially responsive in the endogenous polyamine concentration range, and this effect may be more general. A conserved RNA secondary structure 3′ of the frameshift site has weaker stimulatory and polyamine sensitizing effects on frameshifting.
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Affiliation(s)
- Martina M Yordanova
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Cheng Wu
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - Dmitry E Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Matthew S Sachs
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland; Department of Human Genetics, University of Utah, Salt Lake City, Utah 84112-5330.
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Wang QS, Jan E. Switch from cap- to factorless IRES-dependent 0 and +1 frame translation during cellular stress and dicistrovirus infection. PLoS One 2014; 9:e103601. [PMID: 25089704 PMCID: PMC4121135 DOI: 10.1371/journal.pone.0103601] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 07/03/2014] [Indexed: 11/18/2022] Open
Abstract
Internal ribosome entry sites (IRES) are utilized by a subset of cellular and viral mRNAs to initiate translation during cellular stress and virus infection when canonical cap-dependent translation is compromised. The intergenic region (IGR) IRES of the Dicistroviridae uses a streamlined mechanism in which it can directly recruit the ribosome in the absence of initiation factors and initiates translation using a non-AUG codon. A subset of IGR IRESs including that from the honey bee viruses can also direct translation of an overlapping +1 frame gene. In this study, we systematically examined cellular conditions that lead to IGR IRES-mediated 0 and +1 frame translation in Drosophila S2 cells. Towards this, a novel bicistronic reporter that exploits the 2A “stop-go” peptide was developed to allow the detection of IRES-mediated translation in vivo. Both 0 and +1 frame translation by the IGR IRES are stimulated under a number of cellular stresses and in S2 cells infected by cricket paralysis virus, demonstrating a switch from cap-dependent to IRES-dependent translation. The regulation of the IGR IRES mechanism ensures that both 0 frame viral structural proteins and +1 frame ORFx protein are optimally expressed during virus infection.
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Affiliation(s)
- Qing S. Wang
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eric Jan
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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16
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Sadhu MJ, Moresco JJ, Zimmer AD, Yates JR, Rine J. Multiple inputs control sulfur-containing amino acid synthesis in Saccharomyces cerevisiae. Mol Biol Cell 2014; 25:1653-65. [PMID: 24648496 PMCID: PMC4019496 DOI: 10.1091/mbc.e13-12-0755] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Genes in Saccharomyces cerevisiae involved in sulfur-containing amino acid synthesis are transcriptionally induced by either cysteine or S-adenosyl-methionine deficiency, as well as defects in phosphatidylcholine synthesis. Met30p, a regulator of these genes, changes physically in inducing conditions, which may mediate its regulatory activity. In Saccharomyces cerevisiae, transcription of the MET regulon, which encodes the proteins involved in the synthesis of the sulfur-containing amino acids methionine and cysteine, is repressed by the presence of either methionine or cysteine in the environment. This repression is accomplished by ubiquitination of the transcription factor Met4, which is carried out by the SCF(Met30) E3 ubiquitin ligase. Mutants defective in MET regulon repression reveal that loss of Cho2, which is required for the methylation of phosphatidylethanolamine to produce phosphatidylcholine, leads to induction of the MET regulon. This induction is due to reduced cysteine synthesis caused by the Cho2 defects, uncovering an important link between phospholipid synthesis and cysteine synthesis. Antimorphic mutants in S-adenosyl-methionine (SAM) synthetase genes also induce the MET regulon. This effect is due, at least in part, to SAM deficiency controlling the MET regulon independently of SAM's contribution to cysteine synthesis. Finally, the Met30 protein is found in two distinct forms whose relative abundance is controlled by the availability of sulfur-containing amino acids. This modification could be involved in the nutritional control of SCF(Met30) activity toward Met4.
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Affiliation(s)
- Meru J Sadhu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720
| | - James J Moresco
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037
| | - Anjali D Zimmer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - John R Yates
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037
| | - Jasper Rine
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720
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Mutational analysis of the antizyme-binding element reveals critical residues for the function of ornithine decarboxylase. Biochim Biophys Acta Gen Subj 2013; 1830:5157-65. [DOI: 10.1016/j.bbagen.2013.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/04/2013] [Accepted: 07/08/2013] [Indexed: 01/22/2023]
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18
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Chen J, Liu Q, Yang X, Wu X, Zhang D, He A, Zhan X. Characterization and immunolocalization of mutated ornithine decarboxylase antizyme from Angiostrongylus cantonensis. Mol Biochem Parasitol 2013; 190:76-81. [DOI: 10.1016/j.molbiopara.2013.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 06/14/2013] [Accepted: 06/18/2013] [Indexed: 10/26/2022]
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Kurosinski MA, Lüersen K, Ndjonka D, Younis AE, Brattig NW, Liebau E. Filarial parasites possess an antizyme but lack a functional ornithine decarboxylase. Acta Trop 2013; 126:167-76. [PMID: 23474393 DOI: 10.1016/j.actatropica.2013.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 10/27/2022]
Abstract
In eukaryotes, the key player in polyamine metabolism is the ornithine decarboxylase (ODC) that catalyses the first and rate limiting step in cellular polyamine synthesis. The half life of ODC is strictly regulated by the antizyme (AZ), which promotes its degradation. Older reports on the polyamine situation in filarial parasites indicate a lack of ornithine decarboxylation activity and an increased uptake of polyamines. Our in silico analysis of the Brugia malayi genome revealed only an ODC-like protein that lacks essential residues. Consequently, the recombinant protein had no enzymatic ODC activity. Furthermore, only ODC-like genes were found in the available draft genomes of other filarial parasites. In this ODC-free scenario, we set out to investigate the AZ of O. volvulus (OvAZ). The expression of the recombinant protein allowed us to analyse the localization of OvAZ in different O. volvulus stages as well as to identify it as target for the human humoral immune response. Strong immunostaining was observed in the outer zone of the uterine epithelium as well as in the uterus lumen around the periphery of the developing parasite, indicating a potential role of the OvAZ in the control of polyamine levels during embryonic development. By employing a novel in vivo method using Caenorhabditis elegans, we postulate that the OvAZ enters the secretory pathway. Even though the ODCs are absent in filarial parasites, OvAZ has the ability to bind to various ODCs, thereby demonstrating the functionality of the conserved AZ-binding domains. Finally, pull-down assays show an interaction between B. malayi AZ and the B. malayi ODC-like protein, indicating that the B. malayi ODC-like protein might function as an AZI. Taken together, our results suggest that filarial species do not possess the ODC while retaining the ODC-regulatory proteins AZ and AZI. It is tempting to speculate that both proteins are retained for the regulation of polyamine transport systems.
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Abstract
Frameshifting results from two main mechanisms: genomic insertions or deletions (indels) or programmed ribosomal frameshifting. Whereas indels can disrupt normal protein function, programmed ribosomal frameshifting can result in dual-coding genes, each of which can produce multiple functional products. Here, I summarize technical advances that have made it possible to identify programmed ribosomal frameshifting events in a systematic way. The results of these studies suggest that such frameshifting occurs in all genomes, and I will discuss methods that could help characterize the resulting alternative proteomes.
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Affiliation(s)
- Robin Ketteler
- MRC Laboratory for Molecular Cell Biology, Translational Research Resource Centre, University College London London, UK
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Polyamine metabolism in fungi with emphasis on phytopathogenic species. JOURNAL OF AMINO ACIDS 2012; 2012:837932. [PMID: 22957208 PMCID: PMC3432380 DOI: 10.1155/2012/837932] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 06/23/2012] [Indexed: 12/23/2022]
Abstract
Polyamines are essential metabolites present in all living organisms, and this subject has attracted the attention of researchers worldwide interested in defining their mode of action in the variable cell functions in which they are involved, from growth to development and differentiation. Although the mechanism of polyamine synthesis is almost universal, different biological groups show interesting differences in this aspect that require to be further analyzed. For these studies, fungi represent interesting models because of their characteristics and facility of analysis. During the last decades fungi have contributed to the understanding of polyamine metabolism. The use of specific inhibitors and the isolation of mutants have allowed the manipulation of the pathway providing information on its regulation. During host-fungus interaction polyamine metabolism suffers striking changes in response to infection, which requires examination. Additionally the role of polyamine transporter is getting importance because of its role in polyamine regulation. In this paper we analyze the metabolism of polyamines in fungi, and the difference of this process with other biological groups. Of particular importance is the difference of polyamine biosynthesis between fungi and plants, which makes this process an attractive target for the control of phytopathogenic fungi.
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Takano A, Kakehi JI, Takahashi T. Thermospermine is not a minor polyamine in the plant kingdom. PLANT & CELL PHYSIOLOGY 2012; 53:606-16. [PMID: 22366038 DOI: 10.1093/pcp/pcs019] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Thermospermine is a structural isomer of spermine, which is one of the polyamines studied extensively in the past, and is produced from spermidine by the action of thermospermine synthase encoded by a gene named ACAULIS5 (ACL5) in plants. According to recent genome sequencing analyses, ACL5-like genes are widely distributed throughout the plant kingdom. In Arabidopsis, ACL5 is expressed specifically during xylem formation from procambial cells to differentiating xylem vessels. Loss-of-function mutants of ACL5 display overproliferation of xylem vessels along with severe dwarfism, suggesting that thermospermine plays a role in the repression of xylem differentiation. Studies of suppressor mutants of acl5 that recover the wild-type phenotype in the absence of thermospermine suggest that thermospermine acts on the translation of specific mRNAs containing upstream open reading frames (uORFs). Thermospermine is a novel type of plant growth regulator and may also serve in the control of wood biomass production.
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Affiliation(s)
- Ayaka Takano
- Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
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Abstract
This chapter provides an overview of the polyamine field and introduces the 32 other chapters that make up this volume. These chapters provide a wide range of methods, advice, and background relevant to studies of the function of polyamines, the regulation of their content, their role in disease, and the therapeutic potential of drugs targeting polyamine content and function. The methodology provided in this new volume will enable laboratories already working in this area to expand their experimental techniques and facilitate the entry of additional workers into this rapidly expanding field.
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Affiliation(s)
- Anthony E Pegg
- College of Medicine, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, PA, USA
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Takahashi T, Kakehi JI. Polyamines: ubiquitous polycations with unique roles in growth and stress responses. ANNALS OF BOTANY 2010; 105:1-6. [PMID: 19828463 PMCID: PMC2794062 DOI: 10.1093/aob/mcp259] [Citation(s) in RCA: 254] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 08/18/2009] [Accepted: 09/14/2009] [Indexed: 05/18/2023]
Abstract
BACKGROUND Polyamines are small polycationic molecules found ubiquitously in all organisms and function in a wide variety of biological processes. In the past decade, molecular and genetic studies using mutants and transgenic plants with an altered activity of enzymes involved in polyamine biosynthesis have contributed much to a better understanding of the biological functions of polyamines in plants. POSSIBLE ROLES Spermidine is essential for survival of Arabidopsis embryos. One of the reasons may lie in the fact that spermidine serves as a substrate for the lysine hypusine post-translational modification of the eukaryotic translation initiation factor 5A, which is essential in all eukaryotic cells. Spermine is not essential but plays a role in stress responses, probably through the modulation of cation channel activities, and as a source of hydrogen peroxide during pathogen infection. Thermospermine, an isomer of spermine, is involved in stem elongation, possibly by acting on the regulation of upstream open reading frame-mediated translation. CONCLUSIONS The mechanisms of action of polyamines differ greatly from those of plant hormones. There remain numerous unanswered questions regarding polyamines in plants, such as transport systems and polyamine-responsive genes. Further studies on the action of polyamines will undoubtedly provide a new understanding of plant growth regulation and stress responses.
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Affiliation(s)
- Taku Takahashi
- Graduate School of Natural Science and Technology, Okayama University, 700-8530 Okayama, Japan.
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25
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Ivanov IP, Matsufuji S. Autoregulatory Frameshifting in Antizyme Gene Expression Governs Polyamine Levels from Yeast to Mammals. RECODING: EXPANSION OF DECODING RULES ENRICHES GENE EXPRESSION 2010. [DOI: 10.1007/978-0-387-89382-2_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Drummond DA, Wilke CO. The evolutionary consequences of erroneous protein synthesis. Nat Rev Genet 2009; 10:715-24. [PMID: 19763154 DOI: 10.1038/nrg2662] [Citation(s) in RCA: 360] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Errors in protein synthesis disrupt cellular fitness, cause disease phenotypes and shape gene and genome evolution. Experimental and theoretical results on this topic have accumulated rapidly in disparate fields, such as neurobiology, protein biosynthesis and degradation and molecular evolution, but with limited communication among disciplines. Here, we review studies of error frequencies, the cellular and organismal consequences of errors and the attendant long-range evolutionary responses to errors. We emphasize major areas in which little is known, such as the failure rates of protein folding, in addition to areas in which technological innovations may enable imminent gains, such as the elucidation of translational missense error frequencies. Evolutionary responses to errors fall into two broad categories: adaptations that minimize errors and their attendant costs and adaptations that exploit errors for the organism's benefit.
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Affiliation(s)
- D Allan Drummond
- FAS Center for Systems Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
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ZHANG H, WU XY, LIU DW, WU ZF, WANG C, CHEN YS, LI JQ. Antizyme 1 Gene is Associated with Loin Muscle Area and Marbling in Landrace × Lantang F2 Resource Population. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/s1671-2927(08)60292-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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28
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Kusano T, Berberich T, Tateda C, Takahashi Y. Polyamines: essential factors for growth and survival. PLANTA 2008; 228:367-81. [PMID: 18594857 DOI: 10.1007/s00425-008-0772-7] [Citation(s) in RCA: 463] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Accepted: 06/10/2008] [Indexed: 05/18/2023]
Abstract
Polyamines are low molecular weight, aliphatic polycations found in the cells of all living organisms. Due to their positive charges, polyamines bind to macromolecules such as DNA, RNA, and proteins. They are involved in diverse processes, including regulation of gene expression, translation, cell proliferation, modulation of cell signalling, and membrane stabilization. They also modulate the activities of certain sets of ion channels. Because of these multifaceted functions, the homeostasis of polyamines is crucial and is ensured through regulation of biosynthesis, catabolism, and transport. Through isolation of the genes involved in plant polyamine biosynthesis and loss-of-function experiments on the corresponding genes, their essentiality for growth is reconfirmed. Polyamines are also involved in stress responses and diseases in plants, indicating their importance for plant survival. This review summarizes the recent advances in polyamine research in the field of plant science compared with the knowledge obtained in microorganisms and animal systems.
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Affiliation(s)
- T Kusano
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Karahira, Aoba, Sendai, Miyagi, 980-8577, Japan.
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Affiliation(s)
- Michael Hampsey
- Department of Biochemistry, Division of Nucleic Acid Enzymology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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30
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Miao XP, Li JS, Li HY, Zeng SP, Zhao Y, Zeng JZ. Expression of ornithine decarboxylase in precancerous and cancerous gastric lesions. World J Gastroenterol 2007; 13:2867-71. [PMID: 17569126 PMCID: PMC4395642 DOI: 10.3748/wjg.v13.i20.2867] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 02/05/2007] [Accepted: 02/14/2007] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the expression of ornithine decarboxylase (ODC) in precancerous and cancerous gastric lesions. METHODS We studied the expression of ODC in gastric mucosa from patients with chronic superficial gastritis (CSG, n=32), chronic atrophic gastritis [CAG, n=43; 15 with and 28 without intestinal metaplasia (IM)], gastric dysplasia (DYS, n=11) and gastric cancer (GC, n=48) tissues using immunohistochemical staining. All 134 biopsy specimens of gastric mucosa were collected by gastroscopy. METHODS The positive rate of ODC expression was 34.4%, 42.9%, 73.3%, 81.8% and 91.7% in cases with CSG, CAG without IM, CAG with IM, DYS and GC, respectively (P<0.01), The positive rate of ODC expression increased in the order of CSG < CAG (without IM) < CAG (with IM) < DYS and finally, GC. In addition, ODC positive immunostaining rate was lower in well-differentiated GC than in poorly-differentiated GC (P<0.05). CONCLUSION The expression of ODC is positively correlated with the degree of malignity of gastric mucosa and development of gastric lesions. This finding indicates that ODC may be used as a good biomarker in the screening and diagnosis of precancerous lesions.
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Affiliation(s)
- Xin-Pu Miao
- Department of Gastroenterology, West China Hospital of Sichuan University, 17 Renmin Avenue, Chengdu 610041, Sichuan Province, China.
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31
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Ivanov IP, Atkins JF. Ribosomal frameshifting in decoding antizyme mRNAs from yeast and protists to humans: close to 300 cases reveal remarkable diversity despite underlying conservation. Nucleic Acids Res 2007; 35:1842-58. [PMID: 17332016 PMCID: PMC1874602 DOI: 10.1093/nar/gkm035] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The protein antizyme is a negative regulator of intracellular polyamine levels. Ribosomes synthesizing antizyme start in one ORF and at the codon 5′ adjacent to its stop codon, shift +1 to a second and partially overlapping ORF which encodes most of the protein. The ribosomal frameshifting is a sensor and effector of an autoregulatory circuit which is conserved in animals, fungi and protists. Stimulatory signals encoded 5′ and 3′ of the shift site act to program the frameshifting. Despite overall conservation, many individual branches have evolved specific features surrounding the frameshift site. Among these are RNA pseudoknots, RNA stem-loops, conserved primary RNA sequences, nascent peptide sequences and branch-specific ‘shifty’ codons.
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Affiliation(s)
- Ivaylo P. Ivanov
- Biosciences Institute, University College Cork, Cork, Ireland and Department of Human Genetics, University of Utah, Salt Lake City, UT 84112-5330, USA
- *Correspondence may be addressed to either author at +1-353 21 490 1313+1-353 23 55147 and
| | - John F. Atkins
- Biosciences Institute, University College Cork, Cork, Ireland and Department of Human Genetics, University of Utah, Salt Lake City, UT 84112-5330, USA
- *Correspondence may be addressed to either author at +1-353 21 490 1313+1-353 23 55147 and
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32
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Slootweg EJ, Keller HJHG, Hink MA, Borst JW, Bakker J, Schots A. Fluorescent T7 display phages obtained by translational frameshift. Nucleic Acids Res 2006; 34:e137. [PMID: 17040895 PMCID: PMC1635266 DOI: 10.1093/nar/gkl600] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lytic phages form a powerful platform for the display of large cDNA libraries and offer the possibility to screen for interactions with almost any substrate. To visualize these interactions directly by fluorescence microscopy, we constructed fluorescent T7 phages by exploiting the flexibility of phages to incorporate modified versions of its capsid protein. By applying translational frameshift sequences, helper plasmids were constructed that expressed a fixed ratio of both wild-type capsid protein (gp10) and capsid protein fused to enhanced yellow fluorescent protein (EYFP). The frameshift sequences were inserted between the 3′ end of the capsid gene and the sequence encoding EYFP. Fluorescent fusion proteins are only formed when the ribosome makes a −1 shift in reading frame during translation. Using standard fluorescence microscopy, we could sensitively monitor the enrichment of specific binders in a cDNA library displayed on fluorescent T7 phages. The perspectives of fluorescent display phages in the fast emerging field of single molecule detection and sorting technologies are discussed.
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Affiliation(s)
- Erik J Slootweg
- Laboratory of Molecular Recognition and Antibody Technology, Wageningen University Binnenhaven 5, 6709 PD, Wageningen, The Netherlands.
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33
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Beswick TC, Willert EK, Phillips MA. Mechanisms of allosteric regulation of Trypanosoma cruzi S-adenosylmethionine decarboxylase. Biochemistry 2006; 45:7797-807. [PMID: 16784231 DOI: 10.1021/bi0603975] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
S-Adenosylmethionine decarboxylase (AdoMetDC) is a pyruvoyl-dependent enzyme that catalyzes an essential step in polyamine biosynthesis. The polyamines are required for cell growth, and the biosynthetic enzymes are targets for antiproliferative drugs. The function of AdoMetDC is regulated by the polyamine-precursor putrescine in a species-specific manner. AdoMetDC from the protozoal parasite Trypanosoma cruzi requires putrescine for maximal enzyme activity, but not for processing to generate the pyruvoyl cofactor. The putrescine-binding site is distant from the active site, suggesting a mechanism of allosteric regulation. To probe the structural basis by which putrescine stimulates T. cruzi AdoMetDC we generated mutations in both the putrescine-binding site and the enzyme active site. The catalytic efficiency of the mutant enzymes, and the binding of the diamidine inhibitors, CGP 48664A and CGP 40215, were analyzed. Putrescine stimulates the k(cat)/K(m) for wild-type T. cruzi AdoMetDC by 27-fold, and it stimulates the binding of both inhibitors (IC(50)s decrease 10-20-fold with putrescine). Unexpectedly CGP 48664A activated the T. cruzi enzyme at low concentrations (0.1-10 microM), while at higher concentrations (>100 microM), or in the presence of putrescine, inhibition was observed. Analysis of the mutant data suggests that this inhibitor binds both the putrescine-binding site and the active site, providing evidence that the putrescine-binding site of the T. cruzi enzyme has broad ligand specificity. Mutagenesis of the active site identified residues that are important for putrescine stimulation of activity (F7 and T245), while none of the active site mutations altered the apparent putrescine-binding constant. Mutations of residues in the putrescine-binding site that resulted in reduced (S111R) and enhanced (F285H) catalytic efficiency were both identified. These data provide evidence for coupling between residues in the putrescine-binding site and the active site, consistent with a mechanism of allosteric regulation.
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Affiliation(s)
- Tracy Clyne Beswick
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Boulevard, Dallas, Texas 75390-9041, USA
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Farabaugh PJ, Kramer E, Vallabhaneni H, Raman A. Evolution of +1 programmed frameshifting signals and frameshift-regulating tRNAs in the order Saccharomycetales. J Mol Evol 2006; 63:545-61. [PMID: 16838213 DOI: 10.1007/s00239-005-0311-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Accepted: 03/21/2006] [Indexed: 11/27/2022]
Abstract
Programmed translational frameshifting is a ubiquitous but rare mechanism of gene expression in which mRNA sequences cause the translational machinery to shift reading frames with extreme efficiency, up to at least 50%. The mRNA sequences responsible are deceptively simple; the sequence CUU-AGG-C causes about 40% frameshifting when inserted into an mRNA in the yeast Saccharomyces cerevisiae. The high efficiency of this site depends on a set of S. cerevisiae tRNA isoacceptors that perturb the mechanism of translation to cause the programmed translational error. The simplicity of the system might suggest that it could evolve frequently and perhaps be lost as easily. We have investigated the history of programmed +1 frameshifting in fungi. We find that frameshifting has persisted in two structural genes in budding yeasts, ABP140 and EST3 for about 150 million years. Further, the tRNAs that stimulate the event are equally old. Species that diverged from the lineage earlier both do not employ frameshifting and have a different complement of tRNAs predicted to be inimical to frameshifting. The stability of the coevolution of protein coding genes and tRNAs suggests that frameshifting has been selected for during the divergence of these species.
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Affiliation(s)
- Philip J Farabaugh
- Department of Biological Sciences and Program in Molecular and Cell Biology, University of Maryland Baltimore County, Baltimore, Maryland 21250, USA.
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Kim SN, Choi JH, Park MW, Jeong SJ, Han KS, Kim HJ. Identification of the +1 ribosomal frameshifting site of LRV1-4 by mutational analysis. Arch Pharm Res 2006; 28:956-62. [PMID: 16178423 DOI: 10.1007/bf02973883] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Leishmania virus (LRV)1-4 has been reported to produce a fusion of ORF2 and ORF3 via a programmed +1 frameshift in the region where ORF2 and ORF3 overlap (Lee et al., 1996). However, the exact frameshift site has not been identified. In this study, we compared the frameshift efficiency of a 259bp (nt. 2565-2823), frameshift region of LRV1-4, and the 71bp (nt. 2605-2678) sub-region where ORF2 and ORF3 overlap. We then predicted the frameshift site using a new computer program (Pseudoviewer), and finally identified the specific region associated with the mechanism of the LRV1-4's +1 frameshift by means of a mutational analysis based on the predicted structure of LRV1-4 RNA. The predicted structure was confirmed by biochemical analysis. In order to measure the frameshift efficiency, constructs that generate luciferase without a frameshift or with a +1 frameshift, were generated and in vitro transcription/translation analysis was performed. Measurements of the luciferase activity generated, showed that the frameshift efficiency was about 1% for both the 259bp (LRV1-4 259FS) and 71bp region (LRV1-4 71FS). Luciferase activity was strongly reduced in a mutant (LRV1-4 NH: nt. 2635-2670) with the entire hairpin deleted and in a mutant (LRV1-4 NUS: nt. 2644-2659) with the upper stem of the hairpin deleted. These results indicate that the frameshift site in LRV1-4's is in the 71bp region where ORF2 and ORF3 overlap, and that nt. 2644-2659 (the upward hairpin stem) play a key role in generating the +1 frameshift.
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Affiliation(s)
- Se Na Kim
- College of Pharmacy, Chung Ang University, 221 Huksuk-Dong, Dongjak-Ku, Seoul 156-756, Korea
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Rodríguez-Caso C, Montañez R, Cascante M, Sánchez-Jiménez F, Medina MA. Mathematical modeling of polyamine metabolism in mammals. J Biol Chem 2006; 281:21799-21812. [PMID: 16709566 DOI: 10.1074/jbc.m602756200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Polyamines are considered as essential compounds in living cells, since they are involved in cell proliferation, transcription, and translation processes. Furthermore, polyamine homeostasis is necessary to cell survival, and its deregulation is involved in relevant processes, such as cancer and neurodegenerative disorders. Great efforts have been made to elucidate the nature of polyamine homeostasis, giving rise to relevant information concerning the behavior of the different components of polyamine metabolism, and a great amount of information has been generated. However, a complex regulation at transcriptional, translational, and metabolic levels as well as the strong relationship between polyamines and essential cell processes make it difficult to discriminate the role of polyamine regulation itself from the whole cell response when an experimental approach is given in vivo. To overcome this limitation, a bottom-up approach to model mathematically metabolic pathways could allow us to elucidate the systemic behavior from individual kinetic and molecular properties. In this paper, we propose a mathematical model of polyamine metabolism from kinetic constants and both metabolite and enzyme levels extracted from bibliographic sources. This model captures the tendencies observed in transgenic mice for the so-called key enzymes of polyamine metabolism, ornithine decarboxylase, S-adenosylmethionine decarboxylase and spermine spermidine N-acetyl transferase. Furthermore, the model shows a relevant role of S-adenosylmethionine and acetyl-CoA availability in polyamine homeostasis, which are not usually considered in systemic experimental studies.
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Affiliation(s)
- Carlos Rodríguez-Caso
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Málaga E-29071, Spain
| | - Raúl Montañez
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Málaga E-29071, Spain
| | - Marta Cascante
- Departamento de Bioquímica, Facultad de Química, Universidad de Barcelona, Barcelona E-08028, Spain
| | - Francisca Sánchez-Jiménez
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Málaga E-29071, Spain
| | - Miguel A Medina
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Málaga E-29071, Spain.
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Ivanov IP, Gesteland RF, Atkins JF. Evolutionary specialization of recoding: frameshifting in the expression of S. cerevisiae antizyme mRNA is via an atypical antizyme shift site but is still +1. RNA (NEW YORK, N.Y.) 2006; 12:332-7. [PMID: 16431984 PMCID: PMC1383572 DOI: 10.1261/rna.2245906] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
An autoregulatory translational shift to the +1 frame is required for the expression of ornithine decarboxylase antizyme from fungi to mammals. In most eukaryotes, including all vertebrates and a majority of the studied fungi/yeast, the site on antizyme mRNA where the shift occurs is UCC-UGA. The mechanism of the frameshift on this sequence likely involves nearly universal aspects of the eukaryotic translational machinery. Nevertheless, a mammalian antizyme frameshift cassette yields predominantly -2 frameshift in Saccharomyces cerevisiae, instead of the +1 in mammals. The recently identified endogenous S. cerevisiae antizyme mRNA has an atypical shift site: UGC-GCG-UGA. It is shown here that endogenous S. cerevisiae antizyme frameshifting is +1 rather than -2. We discuss how antizyme frameshifting in budding yeasts exploits peculiarities of their tRNA balance, and relate this to prior studies on Ty frameshifting.
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Abstract
Ornithine decarboxylase (ODC) initiates the polyamine biosynthetic pathway. The amount of ODC is altered in response to many growth factors, oncogenes, and tumor promoters and to changes in polyamine levels. Susceptibility to tumor development is increased in transgenic mice expressing high levels of ODC and is decreased in mice with reduced ODC due to loss of one ODC allele or elevated expression of antizyme, a protein that stimulates ODC degradation. This review describes key factors that contribute to the regulation of ODC levels, which can occur at the levels of transcription, translation, and protein turnover.
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Affiliation(s)
- Anthony E Pegg
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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Hoffman DW, Carroll D, Martinez N, Hackert ML. Solution structure of a conserved domain of antizyme: a protein regulator of polyamines. Biochemistry 2005; 44:11777-85. [PMID: 16128579 DOI: 10.1021/bi051081k] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Antizyme and its isoforms are members of an unusual yet broadly conserved family of proteins, with roles in regulating polyamine levels within cells. Antizyme has the ability to bind and inhibit the enzyme ornithine decarboxylase (ODC), targeting it for degradation at the proteasome; antizyme is also known to affect the transport of polyamines and interact with the antizyme inhibitor protein (AZI), as well as the cell-cycle protein cyclin D1. In the present work, NMR methods were used to determine the solution structure of a stable, folded domain of mammalian antizyme isoform-1 (AZ-1), consisting of amino acid residues 87-227. The protein was found to contain eight beta strands and two alpha helices, with the strands forming a mixed parallel and antiparallel beta sheet. At the level of primary sequence, antizyme is not similar to any protein of known structure, and results show that antizyme exhibits a novel arrangement of its strands and helices. Interestingly, however, the fold of antizyme is similar to that found in a family of acetyl transferases, as well as translation initiation factor IF3, despite a lack of functional relatedness between these proteins. Structural results, combined with amino acid sequence comparisons, were used to identify conserved features among the various homologues of antizyme and their isoforms. Conserved surface residues, including a cluster of acidic amino acids, were found to be located on a single face of antizyme, suggesting this surface is a possible site of interaction with target proteins such as ODC. This structural model provides an essential framework for an improved future understanding of how the different parts of antizyme play their roles in polyamine regulation.
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Affiliation(s)
- David W Hoffman
- Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, USA.
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Chattopadhyay MK, Tabor CW, Tabor H. Studies on the regulation of ornithine decarboxylase in yeast: effect of deletion in the MEU1 gene. Proc Natl Acad Sci U S A 2005; 102:16158-63. [PMID: 16260735 PMCID: PMC1283443 DOI: 10.1073/pnas.0507299102] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Methylthioadenosine is formed during the biosynthesis of spermidine and of spermine and is metabolized by methylthioadenosine phosphorylase, an enzyme missing in several tumor cell lines. In Saccharomyces cerevisiae, this enzyme is coded by the MEU1 gene. We have now studied the effect of the meu1 deletion on polyamine metabolism in yeast. We found that the effects of the meu1Delta mutation mostly depend on the stage of cell growth. As the cell density increases, there is a marked fall in the level of ornithine decarboxylase (ODC) in the MEU1(+) cells, which we show is caused by an antizyme-requiring degradation system. In contrast, there is only a small decrease in the ODC level in the meu1Delta cells. The meu1Delta cells have a higher putrescine and a lower spermidine level than MEU1(+) cells, suggesting that the decreased spermidine level in the meu1Delta cultures is responsible for the greater apparent stability of ODC in the meu1Delta cells. The lower spermidine level in the meu1Delta cells probably results from an inhibition of spermidine synthase by the methylthioadenosine that presumably accumulates in these mutants. In both MEU1(+) and the meu1Delta cultures, the ODC levels were markedly decreased by the addition of spermidine to the media, and thus our results contradict the postulation of Subhi et al. [Subhi, A. L., et al. (2003) J. Biol. Chem. 278, 49868-49873] of a novel regulatory pathway in meu1Delta cells in which ODC is not responsive to spermidine.
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Affiliation(s)
- Manas K Chattopadhyay
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 8, Room 223, Bethesda, MD 20892, USA
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Abstract
The family of antizymes functions as regulators of polyamine homeostasis. They are a class of small, inhibitory proteins, whose expression is regulated by a unique ribosomal frameshift mechanism. They have been shown to inhibit cell proliferation and possess anti-tumor activity. Antizymes bind ornithine decarboxylase (ODC), the key enzyme of polyamine biosynthesis. They inhibit its enzymatic activity and promote the ubiquitin-independent degradation of ODC by the 26S proteasome. In addition, they also negatively regulate polyamine transport. Antizyme-mediated, ubiquitin-independent degradation of ODC is conserved from yeast to man. But recent data suggest that this degradation pathway might not be restricted to ODC alone and could involve newly discovered antizyme binding partners. Interestingly, antizyme proteins have been strictly preserved over a vast evolutionary timeframe. Antizymes consequently represent an important class of proteins that regulate cell growth and metabolism by a diverse set of mechanisms that include protein degradation, inhibition of enzyme activity, small molecule transport and other, potentially not yet discovered properties.
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Affiliation(s)
- Ursula Mangold
- Program in Vascular Biology, Department of Surgery, Children's Hospital, Boston, MA 02115, USA.
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Boeckmann B, Blatter MC, Famiglietti L, Hinz U, Lane L, Roechert B, Bairoch A. Protein variety and functional diversity: Swiss-Prot annotation in its biological context. C R Biol 2005; 328:882-99. [PMID: 16286078 DOI: 10.1016/j.crvi.2005.06.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 06/01/2005] [Accepted: 06/05/2005] [Indexed: 11/25/2022]
Abstract
We all know that the dogma 'one gene, one protein' is obsolete. A functional protein and, likewise, a protein's ultimate function depend not only on the underlying genetic information but also on the ongoing conditions of the cellular system. Frequently the transcript, like the polypeptide, is processed in multiple ways, but only one or a few out of a multitude of possible variants are produced at a time. An overview on processes that can lead to sequence variety and structural diversity in eukaryotes is given. The UniProtKB/Swiss-Prot protein knowledgebase provides a wealth of information regarding protein variety, function and associated disorders. Examples for such annotation are shown and further ones are available at http://www.expasy.org/sprot/tutorial/examples_CRB.
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Affiliation(s)
- Brigitte Boeckmann
- Swiss Institute of Bioinformatics, Centre Médical Universitaire, 1, rue Michel-Servet, 1211 Genève 4, Switzerland.
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Mangold U, Leberer E. Regulation of all members of the antizyme family by antizyme inhibitor. Biochem J 2005; 385:21-8. [PMID: 15355308 PMCID: PMC1134669 DOI: 10.1042/bj20040547] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ODC (ornithine decarboxylase) is the rate-limiting enzyme in polyamine biosynthesis. Polyamines are essential for cellular growth and differentiation but enhanced ODC activity is associated with cell transformation. Post-translationally, ODC is negatively regulated through members of the antizyme family. Antizymes inhibit ODC activity, promote ODC degradation through the 26 S proteasome and regulate polyamine transport. Besides the ubiquitously expressed antizymes 1 and 2, there is the tissue-specific antizyme 3 and an yet uncharacterized antizyme 4. Antizyme 1 has been shown to be negatively regulated through the AZI (antizyme inhibitor) that binds antizyme 1 with higher affinity compared with ODC. In the present study, we show by yeast two- and three-hybrid protein-protein interaction studies that AZI interacts with all members of the antizyme family and is capable of disrupting the interaction between each antizyme and ODC. In a yeast-based ODC complementation assay, we show that human ODC is able to complement fully the function of the yeast homologue of ODC. Co-expression of antizymes resulted in ODC inhibition and cessation of yeast growth. The antizyme-induced growth inhibition could be reversed by addition of putrescine or by the co-expression of AZI. The protein interactions could be confirmed by immunoprecipitation of the human ODC-antizyme 2-AZI complexes. In summary, we conclude that human AZI is capable of acting as a general inhibitor for all members of the antizyme family and that the previously not yet characterized antizyme 4 is capable of binding ODC and inhibiting its enzymic activity similar to the other members of the antizyme family.
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Affiliation(s)
- Ursula Mangold
- Center for Functional Genomics, Aventis Pharma GmbH, 82152 Martinsried, Germany.
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Chabanon H, Aubel C, Larvaron P, Villard C, Carraro V, Brachet P. Ornithine decarboxylase activity is inhibited by the polyamine precursor amino acids at the protein stability level in Caco-2 cells. Biochim Biophys Acta Gen Subj 2005; 1723:74-81. [PMID: 15716048 DOI: 10.1016/j.bbagen.2005.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 01/05/2005] [Accepted: 01/05/2005] [Indexed: 11/29/2022]
Abstract
High concentrations of certain amino acids are known to affect hormonal secretion, immune function, electrolyte balance or metabolic functions. However, there is a lack of knowledge regarding the molecular mechanisms responsible for these effects. We showed that, as well as spermidine transport, the activity of ornithine decarboxylase (ODC), the first and rate-limiting enzyme in polyamine biosynthesis, is decreased in human colon adenocarcinoma cells, Caco-2, following a 4-h supplementation with one of the two polyamine precursor amino acids, L-arginine or L-methionine. Dose-response assays indicated that the inhibitory effect of supplemental L-methionine was stronger than that of supplemental L-arginine. However, it was transient, being even replaced by ODC induction after 8 h, whereas the inhibitory effect of L-arginine lasted for at least 8 h. Unlike L-cysteine, neither L-methionine nor L-arginine could inhibit ODC activity in a crude acellular preparation of the enzyme. The inhibition of ODC activity in cells exposed to L-methionine or L-arginine was due to a decreased abundance of ODC protein without change at the mRNA level and each of these amino acids could counteract ODC induction by a glycine supplement. Contrary to the latter, supplemental L-methionine or L-arginine induced a marked decrease in ODC half-life, concomitantly with an increase in the activity of antizyme, an ODC inhibitory protein. Thus, depending on their nature, amino acids can up- or downregulate ODC activity at the protein stability level.
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Affiliation(s)
- Hervé Chabanon
- Centre de Recherche en Nutrition Humaine d'Auvergne, Institut National de la Recherche Agronomique, Theix, 63122 Saint-Genès Champanelle, France
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Hoyt MA, Zhang M, Coffino P. Probing the ubiquitin/proteasome system with ornithine decarboxylase, a ubiquitin-independent substrate. Methods Enzymol 2005; 398:399-413. [PMID: 16275346 DOI: 10.1016/s0076-6879(05)98033-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ornithine decarboxylase (ODC) is an unusual proteasome substrate-ubiquitin conjugation plays no part in its turnover. It can therefore be used as a probe to distinguish proteasome-mediated actions that do or do not depend on the activity of the ubiquitin system. A 37 residue region of ODC suffices for proteasome interactions, and within this sequence functionally critical residues have been identified. Because no posttranslational modifications are required for substrate preparation, ODC and derived constructs can be readily generated as substrates for either in vitro or in vivo studies. This chapter describes methodologies that allow the use of ODC as a reporter to examine the ubiquitin-proteasome system, both in reconstituted in vitro systems and in living cells.
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Affiliation(s)
- Martin A Hoyt
- Department of Microbiology and Immunology, University of California-San Francisco, San Francisco, CA 94143-0414, USA
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47
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Xu J, Hendrix RW, Duda RL. Conserved translational frameshift in dsDNA bacteriophage tail assembly genes. Mol Cell 2004; 16:11-21. [PMID: 15469818 DOI: 10.1016/j.molcel.2004.09.006] [Citation(s) in RCA: 189] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2004] [Revised: 07/22/2004] [Accepted: 08/10/2004] [Indexed: 11/16/2022]
Abstract
A programmed translational frameshift similar to frameshifts in retroviral gag-pol genes and bacterial insertion elements was found to be strongly conserved in tail assembly genes of dsDNA phages and to be independent of sequence similarities. In bacteriophage lambda, this frameshift controls production of two proteins with overlapping sequences, gpG and gpGT, that are required for tail assembly. We developed bioinformatic approaches to identify analogous -1 frameshifting sites and experimentally confirmed our predictions for five additional phages. Clear evidence was also found for an unusual but analogous -2 frameshift in phage Mu. Frameshifting sites could be identified for most phages with contractile or noncontractile tails whose length is controlled by a tape measure protein. Phages from a broad spectrum of hosts spanning Eubacteria and Archaea appear to conserve this frameshift as a fundamental component of their tail assembly mechanisms, supporting the idea that their tail genes share a common, distant ancestry.
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Affiliation(s)
- Jun Xu
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA
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Koculi E, Lee NK, Thirumalai D, Woodson SA. Folding of the Tetrahymena ribozyme by polyamines: importance of counterion valence and size. J Mol Biol 2004; 341:27-36. [PMID: 15312760 DOI: 10.1016/j.jmb.2004.06.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Revised: 05/28/2004] [Accepted: 06/02/2004] [Indexed: 11/21/2022]
Abstract
Polyamines are abundant metabolites that directly influence gene expression. Although the role of polyamines in DNA condensation is well known, their role in RNA folding is less understood. Non-denaturing gel electrophoresis was used to monitor the equilibrium folding transitions of the Tetrahymena ribozyme in the presence of polyamines. All of the polyamines tested induce near-native structures that readily convert to the native conformation in Mg(2+). The stability of the folded structure increases with the charge of the polyamine and decreases with the size of the polyamine. When the counterion excluded volume becomes large, the transition to the native state does not go to completion even under favorable folding conditions. Brownian dynamics simulations of a model polyelectrolyte suggest that the kinetics of counterion-mediated collapse and the dimensions of the collapsed RNA chains depend on the structure of the counterion. The results are consistent with delocalized condensation of polyamines around the RNA. However, the effective charge of the counterions is lowered by their excluded volume. The stability of the folded RNA is enhanced when the spacing between amino groups matches the distance between adjacent phosphate groups. These results show how changes in intracellular polyamine concentrations could alter RNA folding pathways.
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Affiliation(s)
- Eda Koculi
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
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Newman RM, Mobascher A, Mangold U, Koike C, Diah S, Schmidt M, Finley D, Zetter BR. Antizyme targets cyclin D1 for degradation. A novel mechanism for cell growth repression. J Biol Chem 2004; 279:41504-11. [PMID: 15277517 DOI: 10.1074/jbc.m407349200] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Overproduction of the ornithine decarboxylase (ODC) regulatory protein ODC-antizyme has been shown to correlate with cell growth inhibition in a variety of different cell types. Although the exact mechanism of this growth inhibition is not known, it has been attributed to the effect of antizyme on polyamine metabolism. Antizyme binds directly to ODC, targeting ODC for ubiquitin-independent degradation by the 26 S proteasome. We now show that antizyme induction also leads to degradation of the cell cycle regulatory protein cyclin D1. We demonstrate that antizyme is capable of specific, noncovalent association with cyclin D1 and that this interaction accelerates cyclin D1 degradation in vitro in the presence of only antizyme, cyclin D1, purified 26 S proteasomes, and ATP. In vivo, antizyme up-regulation induced either by the polyamine spermine or by antizyme overexpression causes reduction of intracellular cyclin D1 levels. The antizyme-mediated pathway for cyclin D1 degradation is independent of the previously characterized phosphorylation- and ubiquitination-dependent pathway, because antizyme up-regulation induces the degradation of a cyclin D1 mutant (T286A) that abrogates its ubiquitination. We propose that antizyme-mediated degradation of cyclin D1 by the proteasome may provide an explanation for the repression of cell growth following antizyme up-regulation.
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Affiliation(s)
- Ruchi M Newman
- Program in Vascular Biology and Department of Surgery, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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50
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Ivanov IP, Anderson CB, Gesteland RF, Atkins JF. Identification of a new antizyme mRNA +1 frameshifting stimulatory pseudoknot in a subset of diverse invertebrates and its apparent absence in intermediate species. J Mol Biol 2004; 339:495-504. [PMID: 15147837 PMCID: PMC7125782 DOI: 10.1016/j.jmb.2004.03.082] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Revised: 03/30/2004] [Accepted: 03/31/2004] [Indexed: 10/28/2022]
Abstract
The expression of eukaryotic antizyme genes requires +1 translational frameshifting. The frameshift in decoding most vertebrate antizyme mRNAs is stimulated by an RNA pseudoknot 3' of the frameshift site. Although the frameshifting event itself is conserved in a wide variety of organisms from yeast to mammals, until recently no corresponding 3' RNA pseudoknot was known in invertebrate antizyme mRNAs. A pseudoknot, different in structure and origin from its vertebrate counterparts, is now shown to be encoded by the antizyme genes of distantly related invertebrates. Identification of the 3' frameshifting stimulator in intermediate species or other invertebrates remains unresolved.
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