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Lee MY, Ojeda-Britez S, Ehrbar D, Samwer A, Begley TJ, Melendez JA. Selenoproteins and the senescence-associated epitranscriptome. Exp Biol Med (Maywood) 2022; 247:2090-2102. [PMID: 36036467 PMCID: PMC9837304 DOI: 10.1177/15353702221116592] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Selenium is a naturally found trace element, which provides multiple benefits including antioxidant, anticancer, and antiaging, as well as boosting immunity. One unique feature of selenium is its incorporation as selenocysteine, a rare 21st amino acid, into selenoproteins. Twenty-five human selenoproteins have been discovered, and a majority of these serve as crucial antioxidant enzymes for redox homeostasis. Unlike other amino acids, incorporation of selenocysteine requires a distinctive UGA stop codon recoding mechanism. Although many studies correlating selenium, selenoproteins, aging, and senescence have been performed, it has not yet been explored if the upstream events regulating selenoprotein synthesis play a role in senescence-associated pathologies. The epitranscriptomic writer alkylation repair homolog 8 (ALKBH8) is critical for selenoprotein production, and its deficiency can significantly decrease levels of selenoproteins that are essential for reactive oxygen species (ROS) detoxification, and increase oxidative stress, one of the major drivers of cellular senescence. Here, we review the potential role of epitranscriptomic marks that govern selenocysteine utilization in regulating the senescence program.
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Affiliation(s)
- May Y Lee
- College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
- The RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Stephen Ojeda-Britez
- College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Dylan Ehrbar
- The RNA Institute, University at Albany, Albany, NY 12222, USA
- Department of Biological Sciences, University at Albany, Albany, NY 12222, USA
- RNA Epitranscriptomics and Proteomics Resource, University at Albany, Albany, NY 12222, USA
| | | | - Thomas J Begley
- The RNA Institute, University at Albany, Albany, NY 12222, USA
- Department of Biological Sciences, University at Albany, Albany, NY 12222, USA
- RNA Epitranscriptomics and Proteomics Resource, University at Albany, Albany, NY 12222, USA
| | - J Andres Melendez
- College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
- The RNA Institute, University at Albany, Albany, NY 12222, USA
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2
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Ghelichkhani F, Gonzalez FA, Kapitonova MA, Schaefer-Ramadan S, Liu J, Cheng R, Rozovsky S. Selenoprotein S: A versatile disordered protein. Arch Biochem Biophys 2022; 731:109427. [PMID: 36241082 PMCID: PMC10026367 DOI: 10.1016/j.abb.2022.109427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/16/2022]
Abstract
Selenoprotein S (selenos) is a small, intrinsically disordered membrane protein that is associated with various cellular functions, such as inflammatory processes, cellular stress response, protein quality control, and signaling pathways. It is primarily known for its contribution to the ER-associated degradation (ERAD) pathway, which governs the extraction of misfolded proteins or misassembled protein complexes from the ER to the cytosol for degradation by the proteasome. However, selenos's other cellular roles in signaling are equally vital, including the control of transcription factors and cytokine levels. Consequently, genetic polymorphisms of selenos are associated with increased risk for diabetes, dyslipidemia, and cardiovascular diseases, while high expression levels correlate with poor prognosis in several cancers. Its inhibitory role in cytokine secretion is also exploited by viruses. Since selenos binds multiple protein complexes, however, its specific contributions to various cellular pathways and diseases have been difficult to establish. Thus, the precise cellular functions of selenos and their interconnectivity have only recently begun to emerge. This review aims to summarize recent insights into the structure, interactome, and cellular roles of selenos.
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Affiliation(s)
- Farid Ghelichkhani
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Fabio A Gonzalez
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Mariia A Kapitonova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | | | - Jun Liu
- Enlaza Therapeutics, 11099 N. Torrey Pines Rd, suite 290, La Jolla, CA, 92037, USA
| | - Rujin Cheng
- NGM Biopharmaceuticals, Inc., 333 Oyster Point Blvd, South San Francisco, CA, 94080, USA
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA.
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3
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Copeland PR, Howard MT. Ribosome Fate during Decoding of UGA-Sec Codons. Int J Mol Sci 2021; 22:ijms222413204. [PMID: 34948001 PMCID: PMC8704476 DOI: 10.3390/ijms222413204] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/29/2021] [Accepted: 12/06/2021] [Indexed: 12/14/2022] Open
Abstract
Decoding of genetic information into polypeptides occurs during translation, generally following the codon assignment rules of the organism's genetic code. However, recoding signals in certain mRNAs can overwrite the normal rules of translation. An exquisite example of this occurs during translation of selenoprotein mRNAs, wherein UGA codons are reassigned to encode for the 21st proteogenic amino acid, selenocysteine. In this review, we will examine what is known about the mechanisms of UGA recoding and discuss the fate of ribosomes that fail to incorporate selenocysteine.
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Affiliation(s)
- Paul R. Copeland
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
- Correspondence: (P.R.C.); (M.T.H.)
| | - Michael T. Howard
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
- Correspondence: (P.R.C.); (M.T.H.)
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4
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Atkins JF, O’Connor KM, Bhatt PR, Loughran G. From Recoding to Peptides for MHC Class I Immune Display: Enriching Viral Expression, Virus Vulnerability and Virus Evasion. Viruses 2021; 13:1251. [PMID: 34199077 PMCID: PMC8310308 DOI: 10.3390/v13071251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/11/2021] [Accepted: 06/19/2021] [Indexed: 01/02/2023] Open
Abstract
Many viruses, especially RNA viruses, utilize programmed ribosomal frameshifting and/or stop codon readthrough in their expression, and in the decoding of a few a UGA is dynamically redefined to specify selenocysteine. This recoding can effectively increase viral coding capacity and generate a set ratio of products with the same N-terminal domain(s) but different C-terminal domains. Recoding can also be regulatory or generate a product with the non-universal 21st directly encoded amino acid. Selection for translation speed in the expression of many viruses at the expense of fidelity creates host immune defensive opportunities. In contrast to host opportunism, certain viruses, including some persistent viruses, utilize recoding or adventitious frameshifting as part of their strategy to evade an immune response or specific drugs. Several instances of recoding in small intensively studied viruses escaped detection for many years and their identification resolved dilemmas. The fundamental importance of ribosome ratcheting is consistent with the initial strong view of invariant triplet decoding which however did not foresee the possibility of transitory anticodon:codon dissociation. Deep level dynamics and structural understanding of recoding is underway, and a high level structure relevant to the frameshifting required for expression of the SARS CoV-2 genome has just been determined.
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Affiliation(s)
- John F. Atkins
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
| | - Kate M. O’Connor
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
| | - Pramod R. Bhatt
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Gary Loughran
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
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Howard MT, Copeland PR. New Directions for Understanding the Codon Redefinition Required for Selenocysteine Incorporation. Biol Trace Elem Res 2019; 192:18-25. [PMID: 31342342 PMCID: PMC6801069 DOI: 10.1007/s12011-019-01827-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/10/2019] [Indexed: 10/26/2022]
Abstract
The fact that selenocysteine (Sec) is delivered to the elongating ribosome by a tRNA that recognizes a UGA stop codon makes it unique and a thorn in the side of what was originally thought to be a universal genetic code. The mechanism by which this redefinition occurs has been slowly coming to light over the past 30 years, but key questions remain. This review seeks to highlight the prominent mechanistic questions that will guide the direction of work in the near future. These questions arise from two major aspects of Sec incorporation: (1) novel functions for the Sec insertion sequence (SECIS) that resides in all selenoprotein mRNAs and (2) the myriad of RNA-binding proteins, both known and yet to be discovered, that act in concert to modify the translation elongation process to allow Sec incorporation.
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Affiliation(s)
- Michael T Howard
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - Paul R Copeland
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, 675 Hoes Ln, Piscataway, NJ, 08854, USA.
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Processive Recoding and Metazoan Evolution of Selenoprotein P: Up to 132 UGAs in Molluscs. J Mol Biol 2019; 431:4381-4407. [PMID: 31442478 DOI: 10.1016/j.jmb.2019.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/05/2019] [Accepted: 08/11/2019] [Indexed: 02/06/2023]
Abstract
Selenoproteins typically contain a single selenocysteine, the 21st amino acid, encoded by a context-redefined UGA. However, human selenoprotein P (SelenoP) has a redox-functioning selenocysteine in its N-terminal domain and nine selenium transporter-functioning selenocysteines in its C-terminal domain. Here we show that diverse SelenoP genes are present across metazoa with highly variable numbers of Sec-UGAs, ranging from a single UGA in certain insects, to 9 in common spider, and up to 132 in bivalve molluscs. SelenoP genes were shaped by a dynamic evolutionary process linked to selenium usage. Gene evolution featured modular expansions of an ancestral multi-Sec domain, which led to particularly Sec-rich SelenoP proteins in many aquatic organisms. We focused on molluscs, and chose Pacific oyster Magallana gigas as experimental model. We show that oyster SelenoP mRNA with 46 UGAs is translated full-length in vivo. Ribosome profiling indicates that selenocysteine specification occurs with ∼5% efficiency at UGA1 and approaches 100% efficiency at distal 3' UGAs. We report genetic elements relevant to its expression, including a leader open reading frame and an RNA structure overlapping the initiation codon that modulates ribosome progression in a selenium-dependent manner. Unlike their mammalian counterparts, the two SECIS elements in oyster SelenoP (3'UTR recoding elements) do not show functional differentiation in vitro. Oysters can increase their tissue selenium level up to 50-fold upon supplementation, which also results in extensive changes in selenoprotein expression.
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Rajput B, Pruitt KD, Murphy TD. RefSeq curation and annotation of stop codon recoding in vertebrates. Nucleic Acids Res 2019; 47:594-606. [PMID: 30535227 PMCID: PMC6344875 DOI: 10.1093/nar/gky1234] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 12/03/2018] [Indexed: 12/23/2022] Open
Abstract
Recoding of stop codons as amino acid-specifying codons is a co-translational event that enables C-terminal extension of a protein. Synthesis of selenoproteins requires recoding of internal UGA stop codons to the 21st non-standard amino acid selenocysteine (Sec) and plays a vital role in human health and disease. Separately, canonical stop codons can be recoded to specify standard amino acids in a process known as stop codon readthrough (SCR), producing extended protein isoforms with potential novel functions. Conventional computational tools cannot distinguish between the dual functionality of stop codons as stop signals and sense codons, resulting in misannotation of selenoprotein gene products and failure to predict SCR. Manual curation is therefore required to correctly represent recoded gene products and their functions. Our goal was to provide accurately curated and annotated datasets of selenoprotein and SCR transcript and protein records to serve as annotation standards and to promote basic and biomedical research. Gene annotations were curated in nine vertebrate model organisms and integrated into NCBI's Reference Sequence (RefSeq) dataset, resulting in 247 selenoprotein genes encoding 322 selenoproteins, and 93 genes exhibiting SCR encoding 94 SCR isoforms.
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Affiliation(s)
- Bhanu Rajput
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 8600 Rockville Pike, Bethesda, MD 20894, USA
| | - Kim D Pruitt
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 8600 Rockville Pike, Bethesda, MD 20894, USA
| | - Terence D Murphy
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 8600 Rockville Pike, Bethesda, MD 20894, USA
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8
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Yim SH, Clish CB, Gladyshev VN. Selenium Deficiency Is Associated with Pro-longevity Mechanisms. Cell Rep 2019; 27:2785-2797.e3. [PMID: 31141699 PMCID: PMC6689410 DOI: 10.1016/j.celrep.2019.05.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 11/21/2018] [Accepted: 04/29/2019] [Indexed: 12/15/2022] Open
Abstract
Selenium (Se) is an essential trace element because of its presence in selenoproteins in the form of selenocysteine residue. Both Se deficiency, which compromises selenoprotein functions, and excess Se, which is toxic, have been associated with altered redox homeostasis and adverse health conditions. Surprisingly, we found that, although Se deficiency led to a drastic decline in selenoprotein expression, mice subjected to this dietary regimen for their entire life had normal lifespans. To understand the molecular mechanisms involved, we performed systemic analyses at the level of metabolome, transcriptome, and microRNA profiling. These analyses revealed that Se deficiency reduced amino acid levels, elevated mononucleotides, altered metabolism, and activated signaling pathways linked to longevity-related nutrient sensing. The data show that the metabolic control associated with nutrient sensing coordinately responds to suppressed selenoprotein functions, resulting in normal lifespan under Se deficiency.
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Affiliation(s)
- Sun Hee Yim
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
| | - Clary B Clish
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Vadim N Gladyshev
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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9
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Shetty SP, Sturts R, Vetick M, Copeland PR. Processive incorporation of multiple selenocysteine residues is driven by a novel feature of the selenocysteine insertion sequence. J Biol Chem 2018; 293:19377-19386. [PMID: 30323062 DOI: 10.1074/jbc.ra118.005211] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/05/2018] [Indexed: 11/06/2022] Open
Abstract
RNA stem loop structures have been frequently shown to regulate essential cellular processes. The selenocysteine insertion sequence (SECIS) element, found in the 3' UTRs of all selenoprotein mRNAs, is an example of such a structure, as it is required for the incorporation of the 21st amino acid, selenocysteine (Sec). Selenoprotein synthesis poses a mechanistic challenge because Sec is incorporated during translation in response to a stop codon (UGA). Although it is known that a SECIS-binding protein (SBP2) is required for Sec insertion, the mechanism of action remains elusive. Additional complexity is present in the synthesis of selenoprotein P (SELENOP), which is the only selenoprotein that contains multiple UGA codons and possesses two SECIS elements in its 3' UTR. Thus, full-length SELENOP synthesis requires processive Sec incorporation. Using zebrafish Selenop, in vitro translation assays, and 75Se labeling in HEK293 cells, we found here that processive Sec incorporation is an intrinsic property of the SECIS elements. Specifically, we identified critical features of SECIS elements that are required for processive Sec incorporation. A screen of the human SECIS elements revealed that most of these elements support processive Sec incorporation in vitro; however, we also found that the processivity of Sec incorporation into Selenop in cells is tightly regulated. We propose a model for processive Sec incorporation that involves differential recruitment of SECIS-binding proteins.
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Affiliation(s)
- Sumangala P Shetty
- From the Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey 08854
| | - Ryan Sturts
- From the Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey 08854
| | - Michael Vetick
- From the Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey 08854
| | - Paul R Copeland
- From the Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey 08854
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Shetty S, Copeland PR. Molecular mechanism of selenoprotein P synthesis. Biochim Biophys Acta Gen Subj 2018; 1862:2506-2510. [PMID: 29656121 DOI: 10.1016/j.bbagen.2018.04.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/06/2018] [Accepted: 04/10/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Selenoprotein synthesis requires the reinterpretation of a UGA stop codon as one that encodes selenocysteine (Sec), a process that requires a set of dedicated translation factors. Among the mammalian selenoproteins, Selenoprotein P (SELENOP) is unique as it contains a selenocysteine-rich domain that requires multiple Sec incorporation events. SCOPE OF REVIEW In this review we elaborate on new data and current models that provide insight into how SELENOP is made. MAJOR CONCLUSIONS SELENOP synthesis requires a specific set of factors and conditions. GENERAL SIGNIFICANCE As the key protein required for proper selenium distribution, SELENOP stands out as a lynchpin selenoprotein that is essential for male fertility, proper neurologic function and selenium metabolism.
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Affiliation(s)
- Sumangala Shetty
- Department of Biochemistry and Molecular Biology, Rutgers - Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, United States
| | - Paul R Copeland
- Department of Biochemistry and Molecular Biology, Rutgers - Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, United States.
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Mariotti M, Shetty S, Baird L, Wu S, Loughran G, Copeland PR, Atkins JF, Howard MT. Multiple RNA structures affect translation initiation and UGA redefinition efficiency during synthesis of selenoprotein P. Nucleic Acids Res 2018; 45:13004-13015. [PMID: 29069514 PMCID: PMC5727441 DOI: 10.1093/nar/gkx982] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/11/2017] [Indexed: 01/03/2023] Open
Abstract
Gene-specific expansion of the genetic code allows for UGA codons to specify the amino acid selenocysteine (Sec). A striking example of UGA redefinition occurs during translation of the mRNA coding for the selenium transport protein, selenoprotein P (SELENOP), which in vertebrates may contain up to 22 in-frame UGA codons. Sec incorporation at the first and downstream UGA codons occurs with variable efficiencies to control synthesis of full-length and truncated SELENOP isoforms. To address how the Selenop mRNA can direct dynamic codon redefinition in different regions of the same mRNA, we undertook a comprehensive search for phylogenetically conserved RNA structures and examined the function of these structures using cell-based assays, in vitro translation systems, and in vivo ribosome profiling of liver tissue from mice carrying genomic deletions of 3′ UTR selenocysteine-insertion-sequences (SECIS1 and SECIS2). The data support a novel RNA structure near the start codon that impacts translation initiation, structures located adjacent to UGA codons, additional coding sequence regions necessary for efficient production of full-length SELENOP, and distinct roles for SECIS1 and SECIS2 at UGA codons. Our results uncover a remarkable diversity of RNA elements conducting multiple occurrences of UGA redefinition to control the synthesis of full-length and truncated SELENOP isoforms.
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Affiliation(s)
- Marco Mariotti
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA USA
| | - Sumangala Shetty
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ USA
| | - Lisa Baird
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - Sen Wu
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Gary Loughran
- Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Paul R Copeland
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ USA
| | - John F Atkins
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA.,Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Michael T Howard
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
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