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Wakasugi K, Yokosawa T. Non-canonical functions of human cytoplasmic tyrosyl-, tryptophanyl- and other aminoacyl-tRNA synthetases. Enzymes 2020; 48:207-242. [PMID: 33837705 DOI: 10.1016/bs.enz.2020.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Aminoacyl-tRNA synthetases catalyze the aminoacylation of their cognate tRNAs. Here we review the accumulated knowledge of non-canonical functions of human cytoplasmic aminoacyl-tRNA synthetases, especially tyrosyl- (TyrRS) and tryptophanyl-tRNA synthetase (TrpRS). Human TyrRS and TrpRS have an extra domain. Two distinct cytokines, i.e., the core catalytic "mini TyrRS" and the extra C-domain, are generated from human TyrRS by proteolytic cleavage. Moreover, the core catalytic domains of human TyrRS and TrpRS function as angiogenic and angiostatic factors, respectively, whereas the full-length forms are inactive for this function. It is also known that many synthetases change their localization in response to a specific signal and subsequently exhibit alternative functions. Furthermore, some synthetases function as sensors for amino acids by changing their protein interactions in an amino acid-dependent manner. Further studies will be necessary to elucidate regulatory mechanisms of non-canonical functions of aminoacyl-tRNA synthetases in particular, by analyzing the effect of their post-translational modifications.
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Affiliation(s)
- Keisuke Wakasugi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Takumi Yokosawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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Mini tryptophanyl-tRNA synthetase is required for a synthetic phenotype in vascular smooth muscle cells induced by IFN-γ-mediated β2-adrenoceptor signaling. Cytokine 2020; 127:154940. [DOI: 10.1016/j.cyto.2019.154940] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 01/10/2023]
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Wang Q, Liu D, Song P, Zou MH. Tryptophan-kynurenine pathway is dysregulated in inflammation, and immune activation. Front Biosci (Landmark Ed) 2015; 20:1116-43. [PMID: 25961549 DOI: 10.2741/4363] [Citation(s) in RCA: 228] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The kynurenine (Kyn) pathway is the major route for tryptophan (Trp) metabolism, and it contributes to several fundamental biological processes. Trp is constitutively oxidized by tryptophan 2, 3-dioxygenase in liver cells. In other cell types, it is catalyzed by an alternative inducible indoleamine-pyrrole 2, 3-dioxygenase (IDO) under certain pathophysiological conditions, which consequently increases the formation of Kyn metabolites. IDO is up-regulated in response to inflammatory conditions as a novel marker of immune activation in early atherosclerosis. Besides, IDO and the IDO-related pathway are important mediators of the immunoinflammatory responses in advanced atherosclerosis. In particular, Kyn, 3-hydroxykynurenine, and quinolinic acid are positively associated with inflammation, oxidative stress (SOX), endothelial dysfunction, and carotid artery intima-media thickness values in end-stage renal disease patients. Moreover, IDO is a potential novel contributor to vessel relaxation and metabolism in systemic infections, which is also activated in acute severe heart attacks. The Kyn pathway plays a key role in the increased prevalence of cardiovascular disease by regulating inflammation, SOX, and immune activation.
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Affiliation(s)
| | | | | | - Ming-Hui Zou
- Division of Molecular Medicine, Department of Medicine, and Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA,
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Miyanokoshi M, Tanaka T, Tamai M, Tagawa YI, Wakasugi K. Expression of the rodent-specific alternative splice variant of tryptophanyl-tRNA synthetase in murine tissues and cells. Sci Rep 2013; 3:3477. [PMID: 24327169 PMCID: PMC3858792 DOI: 10.1038/srep03477] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/26/2013] [Indexed: 11/30/2022] Open
Abstract
Tryptophanyl-tRNA synthetase (TrpRS) catalyzes the aminoacylation of tRNATrp. mRNA of a rodent-specific alternative splice variant of TrpRS (SV-TrpRS), which results in the inclusion of an additional hexapeptide at the C-terminus of full-length TrpRS (FL-TrpRS), has been identified in murine embryonic stem (ES) cells. In the present study, we evaluated the expression of mouse TrpRS mRNA by real-time reverse transcription PCR. We show that SV-TrpRS and FL-TrpRS mRNAs are highly expressed in murine ES cells, embryo, spleen, lung, liver and uterus, and that the relative expression of SV-TrpRS compared to FL-TrpRS is significantly less in the brain. Moreover, we found that interferon-γ increases the expression of TrpRS in a mouse cell line. These results provide the first evidence for tissue-specific expression and alternative splicing of mouse TrpRS.
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Affiliation(s)
- Miki Miyanokoshi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
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Wakasugi K. An Exposed Cysteine Residue of Human Angiostatic Mini Tryptophanyl-tRNA Synthetase. Biochemistry 2010; 49:3156-60. [DOI: 10.1021/bi1000239] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Keisuke Wakasugi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan, and PRESTO, Japan Science and Technology (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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Guo M, Schimmel P, Yang XL. Functional expansion of human tRNA synthetases achieved by structural inventions. FEBS Lett 2009; 584:434-42. [PMID: 19932696 DOI: 10.1016/j.febslet.2009.11.064] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 11/17/2009] [Accepted: 11/17/2009] [Indexed: 02/06/2023]
Abstract
Known as an essential component of the translational apparatus, the aminoacyl-tRNA synthetase family catalyzes the first step reaction in protein synthesis, that is, to specifically attach each amino acid to its cognate tRNA. While preserving this essential role, tRNA synthetases developed other roles during evolution. Human tRNA synthetases, in particular, have diverse functions in different pathways involving angiogenesis, inflammation and apoptosis. The functional diversity is further illustrated in the association with various diseases through genetic mutations that do not affect aminoacylation or protein synthesis. Here we review the accumulated knowledge on how human tRNA synthetases used structural inventions to achieve functional expansions.
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Affiliation(s)
- Min Guo
- The Skaggs Institute for Chemical Biology, Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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The life in science. Mol Biol 2008. [DOI: 10.1134/s0026893308050026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ignatenko NA, Yerushalmi HF, Watts GS, Futscher BW, Stringer DE, Marton LJ, Gerner EW. Pharmacogenomics of the polyamine analog 3,8,13,18-tetraaza-10,11-[(E)-1,2-cyclopropyl]eicosane tetrahydrochloride, CGC-11093, in the colon adenocarcinoma cell line HCT1161. Technol Cancer Res Treat 2007; 5:553-64. [PMID: 17121431 DOI: 10.1177/153303460600500602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Polyamine analogs are known to inhibit tumorigenesis at least in part by mimicking some of the regulatory roles of natural polyamines. To begin the identification of those signaling pathways that are involved in differential cellular responses to the synthetic conformationally restricted polyamine analog CGC-11093, we conducted gene expression profiling, proteomic, and genome-wide DNA methylation and histone acetylation analyses of the HCT116 colon adenocarcinoma cell line after treatment with this analog. Gene expression analysis was performed using Affymetrix GeneChip human genome U133 Plus 2.0 arrays. Changes in protein expression were evaluated using 2D polyacrylamide gels followed by LCMS/MS. DNA methylation was measured using 6,800 element CpG island microarrays. Treatment of cells with CGC-11093 at concentrations ranging from 0.1 to 10 microM caused inhibition of cell growth and metabolic activity, but only minimally affected cell viability. Gene expression analysis showed concentration-dependent effects of CGC-11093 on the DNA/RNA binding transcription factor, cell cycle, signaling, transport, cytoskeletal/structural, and serine protease genes. Functional gene analysis revealed distinct expression patterns related to inhibition of cell cycle control, TGF beta signaling, proteasome and RNA polymerase pathways, upregulation of the aminoacyl-tRNA synthesis pathway, and perturbations in the MAPK and Wnt signaling pathways. Microarray results were validated for selected genes with real time RT PCR. Proteomics analysis showed correlative changes in the expression of proteins involved in the regulation of proteasome function (proteasome subunit Y) and tRNA synthesis. CGC-11093 treatment did not produce any detectable changes in DNA methylation or histone acetylation in cells. This study validates specific target pathways for a specific conformationally restricted polyamine analog and suggests the utility of combined gene and DNA methylation microarrays along with proteomic analyses as a useful approach to the evaluation of the mechanisms of action of anticancer drugs.
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Affiliation(s)
- Natalia A Ignatenko
- Department of Cell Biology and Anatomy, Arizona Cancer Center, The University of Arizona, 1515 N. Campbell Avenue, Tucson, Arizona 85724, USA.
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Boasso A, Herbeuval JP, Hardy AW, Anderson SA, Dolan MJ, Fuchs D, Shearer GM. HIV inhibits CD4+ T-cell proliferation by inducing indoleamine 2,3-dioxygenase in plasmacytoid dendritic cells. Blood 2006; 109:3351-9. [PMID: 17158233 PMCID: PMC1852248 DOI: 10.1182/blood-2006-07-034785] [Citation(s) in RCA: 231] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Infection with the human immunodeficiency virus type-1 (HIV) results in acute and progressive numeric loss of CD4(+) T-helper cells and functional impairment of T-cell responses. The mechanistic basis of the functional impairment of the surviving cells is not clear. Indoleamine 2,3-dioxygenase (IDO) is an immunosuppressive enzyme that inhibits T-cell proliferation by catabolizing the essential amino acid tryptophan (Trp) into the kynurenine (kyn) pathway. Here, we show that IDO mRNA expression is elevated in peripheral blood mononuclear cells (PBMCs) from HIV(+) patients compared with uninfected healthy controls (HCs), and that in vitro inhibition of IDO with the competitive blocker 1-methyl tryptophan (1-mT) results in increased CD4(+) T-cell proliferative response in PBMCs from HIV-infected patients. We developed an in vitro model in which exposure of PBMCs from HCs to either infectious or noninfectious, R5- or X4-tropic HIV induced IDO in plasmacytoid dendritic cells (pDCs). HIV-induced IDO was not inhibited by blocking antibodies against interferon type I or type II, which, however, induced IDO in pDCs when added to PBMC cultures. Blockade of gp120/CD4 interactions with anti-CD4 Ab inhibited HIV-mediated IDO induction. Thus, induction of IDO in pDCs by HIV may contribute to the T-cell functional impairment observed in HIV/AIDS by a non-interferon-dependent mechanism.
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Affiliation(s)
- Adriano Boasso
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD 20815, USA.
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Zhu L, Ji F, Wang Y, Zhang Y, Liu Q, Zhang JZ, Matsushima K, Cao Q, Zhang Y. Synovial Autoreactive T Cells in Rheumatoid Arthritis Resist IDO-Mediated Inhibition. THE JOURNAL OF IMMUNOLOGY 2006; 177:8226-33. [PMID: 17114500 DOI: 10.4049/jimmunol.177.11.8226] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A hallmark of T cell-mediated autoimmunity is the persistence of autoreactive T cells. However, it remains to elucidate the manner in which synovial T cells are sustained in patients with rheumatoid arthritis (RA). We found that dendritic cells (DC) and tissues from the synovial joints of RA patients expressed higher levels of IDO than DC from healthy donors. Interestingly, T cells derived from the joint synovial fluid (SF) of RA patients proliferated in response to either autologous or allogeneic IDO-positive DC, an outcome that was not affected by the addition of IDO inhibitor 1-methyl-D-tryptophan (1-MT). In contrast, addition of 1-MT to the culture stimulated with allogeneic or autologous IDO-positive DC significantly enhanced the proliferation of T cells derived from peripheral blood of healthy donors or from peripheral blood of RA patients. Furthermore, we found that functionally active tryptophanyl-tRNA-synthetase (TTS) was significantly elevated in T cells derived from the SF of RA patients, leading to enhanced storage of tryptophan in T cells and to subsequent resistance to IDO-mediated deprivation of tryptophan. The RA SF enhancement of TTS expression in T cells was blocked by mAb to IFN-gamma and TNF-alpha. These results suggest that the resistance of T cells to IDO-mediated deprivation of tryptophan represents a mechanism by which autoreactive T cells are sustained in vivo in RA patients. Specifically, blocking of the up-regulation of TTS expression in T cells presents an avenue for development of a novel therapeutic approach to treatment of RA.
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Affiliation(s)
- Lingqiao Zhu
- Joint Immunology Laboratory, Institute of Health Sciences and Shanghai Institute of Immunology, Chinese Academy of Sciences and Shanghai Jiao Tong University School of Medicine, 225 South Chongqing Road, Shanghai 200225, China
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Bogdanov AA, Karpov VL. RNA-protein interactions at the initial and terminal stages of protein biosynthesis as investigated by Lev Kisselev (on the occasion of his 70th anniversary). BIOCHEMISTRY (MOSCOW) 2006; 71:915-24. [PMID: 16978156 DOI: 10.1134/s0006297906080141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review highlights studies by Lev L. Kisselev and his colleagues on the initial and terminal stages of protein biosynthesis, which cover the period of the last 45 years (1961-2006). They investigated spatial structure of tRNAs, structure and functions of aminoacyl-tRNA-synthetases of higher organisms, and the final step of protein synthesis, termination of translation. L. Kisselev and his team have made three major contributions to these fields of molecular biology; (i) they proposed the hypothesis on the role of anticodon triplet of tRNA in recognition by cognate aminoacyl-tRNA synthetase, which has been experimentally confirmed and is now included in textbooks; (ii) identified primary structures and functions of two eukaryotic protein factors (eRF1 and eRF3) playing a pivotal role in translation termination; (iii) characterized a structural basis for stop codon recognition by eRF1 within the ribosome and discovered the negative structural elements of eRF1, limiting its recognition of one or two stop-codons.
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Affiliation(s)
- A A Bogdanov
- Lomonosov Moscow State University, Moscow, 119992, Russia.
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Mellor AL, Munn DH. IDO expression by dendritic cells: tolerance and tryptophan catabolism. Nat Rev Immunol 2004; 4:762-74. [PMID: 15459668 DOI: 10.1038/nri1457] [Citation(s) in RCA: 1707] [Impact Index Per Article: 85.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Indoleamine 2,3-dioxygenase (IDO) is an enzyme that degrades the essential amino acid tryptophan. The concept that cells expressing IDO can suppress T-cell responses and promote tolerance is a relatively new paradigm in immunology. Considerable evidence now supports this hypothesis, including studies of mammalian pregnancy, tumour resistance, chronic infections and autoimmune diseases. In this review, we summarize key recent developments and propose a unifying model for the role of IDO in tolerance induction.
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Affiliation(s)
- Andrew L Mellor
- Program in Molecular Immunology, Institute of Molecular Medicine and Genetics, Department of Medicine, Medical College of Georgia, Augusta, Georgia 30912, USA.
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Boasso A, Herbeuval JP, Hardy AW, Winkler C, Shearer GM. Regulation of indoleamine 2,3-dioxygenase and tryptophanyl-tRNA-synthetase by CTLA-4-Fc in human CD4+ T cells. Blood 2004; 105:1574-81. [PMID: 15466932 DOI: 10.1182/blood-2004-06-2089] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Indoleamine-2,3-dioxygenase (IDO) and tryptophanyl-tRNA-synthetase (TTS) are interferon-gamma (IFN-gamma)-inducible enzymes that are responsible for tryptophan degradation and for its use in protein synthesis, respectively. IFN-gamma-induced IDO has immunomodulatory properties in murine and human models. A concomitant increase of TTS has been postulated to protect the IDO-expressing cells from tryptophan catabolism. IDO can be induced in dendritic cells (DCs) by recombinant soluble cytotoxic T lymphocyte antigen-4 (CTLA-4-Fc). We investigated the effects of CTLA-4-Fc on IDO and TTS mRNA expression in human peripheral blood mononuclear cells (PBMCs) and isolated leukocyte subsets. CTLA-4-Fc exposure induced increased IDO and TTS expression in unseparated PBMCs, as well as in monocyte-derived mature DCs. CD4(+) T cells isolated from CTLA-4-Fc-treated PBMCs showed increased IDO and TTS compared with untreated cells. CD8(+) T cells from CTLA-4-Fc-treated PBMCs expressed increased levels of TTS but not IDO. Pretreatment of PBMCs with CTLA-4-Fc inhibited the activation of CD4(+) T cells induced by influenza A virus (Flu) or phytohemagglutinin A (PHA), but had no effect on CD8(+) T cells. This is the first report of IDO and TTS regulation by the CTLA-4-B7 system in human CD4(+) and CD8(+) T cells, and raises the possibility that these 2 tryptophan-modulating enzymes provide an important mechanism for regulating immune responses.
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Affiliation(s)
- Adriano Boasso
- Experimental Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Liu J, Shue E, Ewalt KL, Schimmel P. A new gamma-interferon-inducible promoter and splice variants of an anti-angiogenic human tRNA synthetase. Nucleic Acids Res 2004; 32:719-27. [PMID: 14757836 PMCID: PMC373357 DOI: 10.1093/nar/gkh240] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Two forms of human tryptophanyl-tRNA synthetase (TrpRS) are produced in vivo through alternative mRNA splicing. The two forms, full-length TrpRS and mini TrpRS, are catalytically active, but are distinguished by the striking anti-proliferative and anti-angiogenic activity specific to mini TrpRS. Here we describe two new splice variants of human TrpRS mRNA. Their production was strongly regulated by gamma-interferon (IFN-gamma), an anti-proliferative cytokine known to stimulate the expression of other anti-angiogenic factors. A new IFN-gamma-sensitive promoter was demonstrated to drive production of these splice variants. In human endothelial cells, both the newly discovered and a previously reported promoter were shown to respond specifically to IFN-gamma and not to other cytokines such as tumor necrosis factor-alpha, transforming growth factor-beta, interleukin-4 or erythropoietin. In addition, both promoters were stimulated by the 'downstream' interferon regulatory factor 1 that, in turn, is known to be regulated by the 'upstream' signal transducer and activator of transcription 1alpha subunit. Thus, the tandem promoters provide a dual system to regulate expression and alternative splicing of human TrpRS in vivo.
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Affiliation(s)
- Jianming Liu
- The Skaggs Institute for Chemical Biology and the Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, BCC-379, La Jolla, CA 92037, USA
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Gromov P, Skovgaard GL, Palsdottir H, Gromova I, Østergaard M, Celis JE. Protein profiling of the human epidermis from the elderly reveals up-regulation of a signature of interferon-gamma-induced polypeptides that includes manganese-superoxide dismutase and the p85beta subunit of phosphatidylinositol 3-kinase. Mol Cell Proteomics 2003; 2:70-84. [PMID: 12644569 DOI: 10.1074/mcp.m200051-mcp200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aging of the human skin is a complex process that consists of chronological and extrinsic aging, the latter caused mainly by exposure to ultraviolet radiation (photoaging). Here we present studies in which we have used proteomic profiling technologies and two-dimensional (2D) PAGE database resources to identify proteins whose expression is deregulated in the epidermis of the elderly. Fresh punch biopsies from the forearm of 20 pairs of young and old donors (21-30 and 75-92 years old, respectively) were dissected to yield an epidermal fraction that consisted mainly of differentiated cells. One- to two-mm3 epidermal pieces were labeled with [35S]methionine for 18 h, lysed, and subjected to 2D PAGE (isoelectric focusing and non-equilibrium pH gradient electrophoresis) and phosphorimage autoradiography. Proteins were identified by matching the gels with the master 2D gel image of human keratinocytes (proteomics.cancer.dk). In selected cases 2D PAGE immunoblotting and/or mass spectrometry confirmed the identity. Quantitative analysis of 172 well focused and abundant polypeptides showed that the level of most proteins (148) remains unaffected by the aging process. Twenty-two proteins were consistently deregulated by a factor of 1.5 or more across the 20 sample pairs. Among these we identified a group of six polypeptides (Mx-A, manganese-superoxide dismutase, tryptophanyl-tRNA synthetase, the p85beta subunit of phosphatidylinositol 3-kinase, and proteasomal proteins PA28-alpha and SSP 0107) that is induced by interferon-gamma in primary human keratinocytes and that represents a specific protein signature for the effect of this cytokine. Changes in the expression of the eukaryotic initiation factor 5A, NM23 H2, cyclophilin A, HSP60, annexin I, and plasminogen activator inhibitor 2 were also observed. Two proteins exhibited irregular behavior from individual to individual. Besides arguing for a role of interferon-gamma in the aging process, the biological activities associated with the deregulated proteins support the contention that aging is linked with increased oxidative stress that could lead to apoptosis in vivo.
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Affiliation(s)
- Pavel Gromov
- Department of Medical Biochemistry and Danish Centre for Molecular Gerontology, The University of Aarhus, Ole Worms Allé, build. 170, DK-8000 Aarhus C, Denmark.
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O'Hanlon TP, Miller FW. Genomic organization, transcriptional mapping, and evolutionary implications of the human bi-directional histidyl-tRNA synthetase locus (HARS/HARSL). Biochem Biophys Res Commun 2002; 294:609-14. [PMID: 12056811 DOI: 10.1016/s0006-291x(02)00525-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Histidyl-tRNA synthetase catalyses the covalent ligation of histidine to its cognate tRNA as an early step in protein biosynthesis. In humans, the histidyl-tRNA synthetase gene (HARS) is oriented opposite of a synthetase-like gene (HARSL) that bears striking homology to HARS. In this report, we describe the genomic organization of the HARS/HARSL locus and map multiple transcripts originating from a bi-directional promoter controlling the differential expression of these genes. The HARS and HARSL genes each contain 13 exons with strong structural and sequence homology over exons 3-12. HARS transcripts originate from two distinct promoters; a cluster of short transcripts map 15-65 bp upstream of the HARS ORF while a single, longer transcript (352 bp 5(')-UTR) maps to a distal promoter. Similarly, multiple HARSL transcripts (mapping 10-198 bp upstream of its ORF) are produced by the shared bi-directional promoter. Human and rodent HARS/HARSL loci are homologous and support a model of inverted gene duplication to explain the emergence of HARSL during mammalian evolution.
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Affiliation(s)
- Terrance P O'Hanlon
- Environmental Autoimmunity Group, National Institute of Environmental Health Sciences, National Institutes of Health, Bethesda, MD 20892, USA.
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Seshaiah P, Andrew DJ. WRS-85D: A tryptophanyl-tRNA synthetase expressed to high levels in the developing Drosophila salivary gland. Mol Biol Cell 1999; 10:1595-608. [PMID: 10233165 PMCID: PMC25347 DOI: 10.1091/mbc.10.5.1595] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In a screen for genes expressed in the Drosophila embryonic salivary gland, we identified a tryptophanyl-tRNA synthetase gene that maps to cytological position 85D (WRS-85D). WRS-85D expression is dependent on the homeotic gene Sex combs reduced (Scr). In the absence of Scr function, WRS-85D expression is lost in the salivary gland primordia; conversely, ectopic expression of Scr results in expression of WRS-85D in new locations. Despite the fact that WRS-85D is a housekeeping gene essential for protein synthesis, we detected both WRS-85D mRNA and protein at elevated levels in the developing salivary gland. WRS-85D is required for embryonic survival; embryos lacking the maternal contribution were unrecoverable, whereas larvae lacking the zygotic component died during the third instar larval stage. We showed that recombinant WRS-85D protein specifically charges tRNATrp, and WRS-85D is likely to be the only tryptophanyl-tRNA synthetase gene in Drosophila. We characterized the expression patterns of all 20 aminoacyl-tRNA synthetases and found that of the four aminoacyl-tRNA synthetase genes expressed at elevated levels in the salivary gland primordia, WRS-85D is expressed at the highest level throughout embryogenesis. We also discuss the potential noncanonical activities of tryptophanyl-tRNA synthetase in immune response and regulation of cell growth.
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Affiliation(s)
- P Seshaiah
- Department of Cell Biology and Anatomy, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA
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Wakasugi K, Quinn CL, Tao N, Schimmel P. Genetic code in evolution: switching species-specific aminoacylation with a peptide transplant. EMBO J 1998; 17:297-305. [PMID: 9427763 PMCID: PMC1170380 DOI: 10.1093/emboj/17.1.297] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The genetic code is established in aminoacylation reactions whereby amino acids are joined to tRNAs bearing the anticodons of the genetic code. Paradoxically, while the code is universal there are many examples of species-specific aminoacylations, where a tRNA from one taxonomic domain cannot be acylated by a synthetase from another. Here we consider an example where a human, but not a bacterial, tRNA synthetase charges its cognate eukaryotic tRNA and where the bacterial, but not the human, enzyme charges the cognate bacterial tRNA. While the bacterial enzyme has less than 10% sequence identity with the human enzyme, transplantation of a 39 amino acid peptide from the human into the bacterial enzyme enabled the latter to charge its eukaryotic tRNA counterpart in vitro and in vivo. Conversely, substitution of the corresponding peptide of the bacterial enzyme for that of the human enabled the human enzyme to charge bacterial tRNA. This peptide element discriminates a base pair difference in the respective tRNA acceptor stems. Thus, functionally important co-adaptations of a synthetase to its tRNA act as small modular units that can be moved across taxonomic domains and thereby preserve the universality of the code.
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Affiliation(s)
- K Wakasugi
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Vartanian A, Prudovsky I, Suzuki H, Dal Pra I, Kisselev L. Opposite effects of cell differentiation and apoptosis on Ap3A/Ap4A ratio in human cell cultures. FEBS Lett 1997; 415:160-2. [PMID: 9350987 DOI: 10.1016/s0014-5793(97)01086-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The biological role of diadenosine oligophosphates (DAOP) remains obscure in spite of numerous attempts to solve this enigma. It is known that Ap3A contrary to Ap4A accumulates in human cultured cells treated with interferons (IFNs) alpha or gamma. Since IFNs are considered as antiproliferative regulators, we assumed that different cell status may be associated with varying intracellular levels of DAOP. Promyelocytic human cell line HL60 induced by phorbol ester (TPA) to differentiate to macrophage-like cells in culture exhibits a profound loss of proliferative potential. Here we have shown a 4-5-fold increase in Ap3A concentration in HL60 cells induced by TPA, similar to the effect of IFN, while the Ap4A concentration remained unchanged. On the contrary, in cells undergoing apoptosis induced by VP16, a topoisomerase II inhibitor, the Ap3A concentration considerably decreased, while the Ap4A concentration increased. These findings combined with earlier results suggest an involvement of the Ap3A/Ap4A ratio in signal transduction pathways controlling the cell status.
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Affiliation(s)
- A Vartanian
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow
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21
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Turpaev K, Hartmann R, Kisselev L, Justesen J. Ap3A and Ap4A are primers for oligoadenylate synthesis catalyzed by interferon-inducible 2-5A synthetase. FEBS Lett 1997; 408:177-81. [PMID: 9187362 DOI: 10.1016/s0014-5793(97)00365-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The biological role of Ap3A synthesized in cells by tryptophanyl-tRNA synthetase (WRS) is unknown. Previously we have demonstrated that the cellular level of Ap3A significantly increases after interferon treatment. Here we show that the human 46 kDa 2-5A synthetase efficiently utilizes Ap3A as a primer for oligoadenylate synthesis. The Km for Ap3A is several-fold lower than for Ap4A and 100-fold lower than for ATP. This implies that Ap3A might be a natural primer for the 2'-adenylation reaction catalysed by 2-5A synthetase. Since WRS and 2-5A synthetase are both interferon-inducible proteins, a new link between two interferon-dependent enzymes is established.
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Affiliation(s)
- K Turpaev
- Department of Molecular and Structural Biology, Aarhus University, Denmark
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22
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Lim EH, Corrochano LM, Elgar G, Brenner S. Genomic structure and sequence analysis of the valyl-tRNA synthetase gene of the Japanese pufferfish, Fugu rubripes. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 1997; 7:141-51. [PMID: 9254008 DOI: 10.3109/10425179709034030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The genomic sequence and exon-intron organisation of the valyl-tRNA synthetase gene in the Japanese pufferfish, Fugu rubripes, have been determined. This single-copy Fugu gene spans 8.5 kb, about 2.5 times smaller than that in man (21 kb). It contains 29 exons, with the largest intron being 1008 bp. The predicted polypeptide consists of 1217 amino acids, with a molecular weight of 138 kD and an isoelectric point of 7.27. It shares 40% identity in the overlapping region with its homolog in bacteria, 47% with yeast, and 67% with man. The Fugu gene has an additional N-terminal sequence which shows strong similarity to elongation factory-1gamma, a feature it shares only with the human sequence, but not with any other lower eukaryote or prokaryote studied so far. This N-terminal segment is encoded in the first six exons, suggesting their capture by a translocation through introns. Indeed, the acquisition of extra domains to perform related functions in RNA splicing and translation of polypeptides has already been observed in other aminoacyl-tRNA synthetases. Two cDNA sequences of human valyl-tRNA synthetase have been published, with discrepancies between them. Aided by comparisons with the Fugu gene, three of these discrepancies have been resolved, involving the elucidation of the sequence and positions of two introns. This compact vertebrate genome has demonstrated its value as a tool for the analysis of genes at the genomic level.
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Affiliation(s)
- E H Lim
- Department of Medicine, Addenbrookes Hospital, Cambridge, United Kingdom.
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23
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Lazard M, Agou F, Cavarelli J, Latreille MT, Moras D, Mirande M. Genomic organization of the rat aspartyl-tRNA synthetase gene family: a single active gene and several retropseudogenes. Gene 1996; 180:197-205. [PMID: 8973367 DOI: 10.1016/s0378-1119(96)00455-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The genomic organization of the gene encoding rat aspartyl-tRNA synthetase (AspRS), a class II aminoacyl-tRNA synthetase (aaRS), was determined. A single active gene and several pseudogenes were isolated from a rat genomic DNA library and characterized. The active DRS1 gene encoding the rat AspRS spans approximately 60 kb and is divided into 16 exons. Exons 8-16, encoding the nt-binding domain of the synthetase, are clustered in the 3'-region of the gene, whereas exons 3, 4, and 5, encoding the anticodon-binding domain are separated by large introns (up to 15 kb) containing LINE sequences. One of the pseudogenes, psi DRS1, has a nt sequence 93% identical to that of the complete cDNA sequence of rat AspRS but several stop codons interrupt the coding sequence, thus identifying psi DRS1 to an inactive processed pseudogene. Two repetitive elements from the LINE family are inserted into psi DRS1. Calculation of nt substitution rates suggests that psi DRS1 sequences arose approximately 27 Myr ago. The other pseudogene, psi DRS2, should be more ancient. Taken together, these results clearly demonstrate that the AspRS gene family is composed of only one active gene. The availability of the gene structure of AspRS could help to clarify molecular evolution of class II aaRS.
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Affiliation(s)
- M Lazard
- Laboratoire d'Enzymologie, CNRS, Gif sur Yvette, France
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24
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Shen T, Anderson SL, Rubin BY. Use of alternative polyadenylation sites in the synthesis of mRNAs encoding the interferon-induced tryptophanyl tRNA synthetase. Gene 1996; 179:225-9. [PMID: 8972904 DOI: 10.1016/s0378-1119(96)00361-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The interferon-mediated induction of the gene encoding the human tryptophanyl tRNA synthetase (WRS) results in the production of two mRNA species differing in size by approximately 800 base pairs (bp). Two distinctly sized cDNAs differing by approximately 800 bp were isolated from a cDNA library generated from mRNA prepared from IFN-gamma-treated cells. Northern blot analysis using cDNA probes recognizing different regions of the WRS mRNA reveals distinctly sized mRNAs differing in the length of their 3' untranslated regions. Differential display analysis using oligo dT primers demonstrates that the different sized WRS mRNAs result from alternative polyadenylation of this transcript.
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Affiliation(s)
- T Shen
- Department of Biological Sciences, Fordham University, Bronx, NY 10458, USA
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25
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Turpaev KT, Zakhariev VM, Sokolova IV, Narovlyansky AN, Amchenkova AM, Justesen J, Frolova LY. Alternative processing of the tryptophanyl-tRNA synthetase mRNA from interferon-treated human cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 240:732-7. [PMID: 8856077 DOI: 10.1111/j.1432-1033.1996.0732h.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have analysed the structure of mRNA isoforms of the human gene encoding tryptophanyl-tRNA synthetase (Trp-tRNA synthetase) expressed in the epithelial CaOv cells and MT-4 lymphocytes. The Trp-tRNA synthetase gene is induced by interferon-gamma in both lines and, in MT-4 lymphocytes, also by interferon-alpha. Four Trp-tRNA synthetase mRNA isoforms have different combinations of the first exons IA, IB and II. Two transcription initiation sites (P1 and P2) were detected 90 bp from each other. Processing of the primary transcript initiated from the P1 start site generates the mRNA isoform where exon IA joins to exon II. The other three isoforms are produced by alternative splicing of the primary transcript produced from the P2 start site. Isoform 2 has a 3'-end fragment of exon IA joined to exon II. Isoform 3 contains exons IA and IB. Isoform 4 contains exon IA and exon III and lacks exon II encoding the N-terminus of the Trp-tRNA synthetase. Therefore, the two primary transcripts of the Trp-tRNA synthetase gene differ only in the 5' flank sequence between P1 and P2, and this fragment regulates their processing. Both interferon-alpha and interferon-gamma induce exon IA-containing and exon IB-containing isoforms of the Trp-tRNA synthetase mRNA.
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Affiliation(s)
- K T Turpaev
- Engelhardt Institute of Molecular Biology, Moscow, Russia
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26
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Konan KV, Taylor MW. Importance of the two interferon-stimulated response element (ISRE) sequences in the regulation of the human indoleamine 2,3-dioxygenase gene. J Biol Chem 1996; 271:19140-5. [PMID: 8702590 DOI: 10.1074/jbc.271.32.19140] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Indoleamine 2,3-dioxygenase (INDO) is the rate-limiting enzyme in the catabolism of the essential amino acid L-tryptophan. It is induced strongly in many cell lines following interferon-gamma treatment. We report the cloning and characterization of the full-length human INDO promoter. This promoter is 1,245 base pairs long and includes two interferon-stimulated response elements (ISRE) separated by an approximately 1-kilobase sequence. The presence of these two ISREs is critical for maximum INDO promoter activity (50-fold induction). When the ISREs are present in two separate fragments cloned upstream of the chloramphenicol acetyltransferase (CAT) reporter vector, the INDO promoter activity drops significantly (7-fold induction). 5' end deletions of the wild type promoter sequence indicate that removal of the ISRE (ISRE1) at position -1126 reduces the induction level to approximately 25-fold. This activity does not change appreciably when the promoter is deleted down to position -241. Furthermore, site-directed mutagenesis of ISRE1 also decreases the promoter activity in a similar way. When ISRE1 is kept intact, deletion of the second ISRE (ISRE2) at position -111 leads to only 11-fold induction of the promoter. A similar result is obtained when substitution mutations are introduced in ISRE2. Deletion of a 748-base pair sequence between the two ISREs only shows a slight decrease in the INDO promoter activity. These data indicate that the two ISRE sequences are required for the full transcriptional induction of the interferon-gamma-inducible human INDO gene. INDO activity is not induced in the hepatic cell line HepG2. An analysis of INDO-CAT activity in this cell line indicated that the lack of INDO activity was at the transcriptional level and could reflect either the presence of a repressor or lack of a transcription factor. This lack of induction could be correlated with a truncated or unstable IRF-1. However, the levels of IRF-2, JAK2, and STAT 91 were similar in both ME180 and HepG2 cells.
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Affiliation(s)
- K V Konan
- Institute for Molecular and Cellular Biology, Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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27
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Brenner S, Corrochano LM. Translocation events in the evolution of aminoacyl-tRNA synthetases. Proc Natl Acad Sci U S A 1996; 93:8485-9. [PMID: 8710896 PMCID: PMC38698 DOI: 10.1073/pnas.93.16.8485] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We have characterized hisS, the gene encoding the histidyl-tRNA synthetase (HisRS) from the tetraodontoid fish Fugu rubripes. The hisS gene is about 3.5 kbp long and contains 13 exons and 12 introns of 172 bp, on average. The Fugu hisS gene encodes a putative protein of 519 amino acids with the three motifs identified as signatures of class 2 aminoacyl-tRNA synthetases. A model for the shifting of intron 8 between Fugu and hamster is proposed based on the successive appearance of a cryptic splicing site followed by an insertion mutation that created a new acceptor site. In addition, sequence comparisons suggest that the hisS gene has undergone a translocation through the first intron. As a result, the Fugu HisRS has an N-terminal sequence markedly different from that in the human and hamster enzymes. We propose that similar events have been responsible for variations at the N-terminal end of other aminoacyl-tRNA synthetases. Our analysis suggests that this involves exchanges through introns of two exons encoding an ancestral 32-amino acid motif.
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Affiliation(s)
- S Brenner
- Department of Medicine, University of Cambridge School of Clinical Medicine, United Kingdom
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28
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Vartanian A, Narovlyansky A, Amchenkova A, Turpaev K, Kisselev L. Interferons induce accumulation of diadenosine triphosphate (Ap3A) in human cultured cells. FEBS Lett 1996; 381:32-4. [PMID: 8641433 DOI: 10.1016/0014-5793(96)00073-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
After incubation of human monocytes J96 and human myeloid leukemia HL60 cells with interferons (IFN) alpha or gamma, the Ap3A concentration considerably increases in parallel with accumulation of tryptophanyl-tRNA synthetase (TrpRS, EC 6.1.1.2). The Ap3A formation in response to IFNs is catalysed by an excessive amount of TrpRS. Although the Ap3A function still remains unknown, its accumulation may imply the Ap3A involvement in the IFN-signalling pathway.
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Affiliation(s)
- A Vartanian
- Engelhardt Institute of Molecular Biology, Russian Academy Sciences, Moscow, Russia
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29
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Affiliation(s)
- D C Yang
- Department of Chemistry, Georgetown University, Washington DC 20057, USA
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30
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Xue H, Wong JT. Interferon induction of human tryptophanyl-tRNA synthetase safeguards the synthesis of tryptophan-rich immune-system proteins: a hypothesis. Gene 1995; 165:335-9. [PMID: 8522205 DOI: 10.1016/0378-1119(95)00550-p] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ever since the discovery that the human tryptophanyl-tRNA synthetase (TrpRS)-encoding gene is induced by interferon (IFN) [J. Fleckner et al., Proc. Natl. Acad. Sci. USA 88 (1991) 11520-11524] and contains IFN-response regulatory elements [Frolova et al., Gene 128 (1993) 237-245], the biological rationale for this induction has remained unresolved. A survey of immune system proteins in this study reveals that the human major histocompatibility complex (MHC) antigens, beta-2-microglobulin (beta MG) and complement factor B, which are known to be induced by IFN, together with immunoglobulins (Ig) are all exceptionally enriched in Trp residues, as compared to human proteins in general. It also reveals the conservation of a sequence motif, CX10-17 WX26-62C, in Ig domains. The conservation of this sequence motif and the utility of Trp residues within antigen-binding sites clearly contribute to the Trp enrichment in Ig. These observations suggest a biological rationale for the induction of TrpRS by IFN in safeguarding Trp incorporation for the IFN-enhanced synthesis of immunological molecules.
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31
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Tolstrup AB, Bejder A, Fleckner J, Justesen J. Transcriptional regulation of the interferon-gamma-inducible tryptophanyl-tRNA synthetase includes alternative splicing. J Biol Chem 1995; 270:397-403. [PMID: 7814400 DOI: 10.1074/jbc.270.1.397] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have investigated the transcriptional control elements of the human interferon (IFN)-gamma-induced tryptophanyl-tRNA synthetase (hWRS) gene and characterized the transcripts. Transcription leads to a series of mRNAs with different combinations of the first exons. The full-length mRNA codes for a 55-kDa protein (hWRS), but a mRNA lacking exon II is present in almost as high amounts as the full-length transcript. This alternatively spliced mRNA is probably translated into a 48-kDa protein starting from Met48 in exon III. The predicted 48-kDa protein corresponds exactly to an IFN-gamma-inducible protein previously detected by two-dimensional gel electrophoresis. By isolation of genomic clones and construction of plasmids containing hWRS promoter fragments fused to the secreted alkaline phosphatase reporter gene we have mapped a promoter region essential for IFN-mediated gene activation. This region contains IFN-stimulated response elements (ISRE) as well as a Y-box and a gamma-activated sequence (GAS) element. IFN-gamma inducibility of hWRS depends on ongoing protein synthesis, suggesting that so far undescribed transcription factors apart from the latent GAS-binding protein p91 contribute to gene activation. This could be interferon-regulatory factor-1, which binds ISRE elements.
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Affiliation(s)
- A B Tolstrup
- Department of Molecular Biology, University of Aarhus, Denmark
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32
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A novel interferon-alpha-regulated, DNA-binding protein participates in the regulation of the IFP53/tryptophanyl-tRNA synthetase gene. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37235-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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33
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Kisselev LL, Wolfson AD. Aminoacyl-tRNA synthetases from higher eukaryotes. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1994; 48:83-142. [PMID: 7938555 DOI: 10.1016/s0079-6603(08)60854-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- L L Kisselev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow
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34
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Kisselev L, Frolova L, Haenni AL. Interferon inducibility of mammalian tryptophanyl-tRNA synthetase: new perspectives. Trends Biochem Sci 1993; 18:263-7. [PMID: 7692626 DOI: 10.1016/0968-0004(93)90178-p] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Mammalian aminoacyl-tRNA synthetases are indispensible components of the cell's protein-synthesizing machinery. Surprisingly, recent experiments have demonstrated that synthesis of tryptophanyl-tRNA synthetase (WRS) is markedly enhanced after incubation of human cells with interferons. Why is this housekeeping enzyme interferon-inducible? Several hypotheses have been suggested. One hypothesis, that premature termination of protein synthesis was involved, was boosted by the discovery that the deduced amino acid sequence of the mammalian peptide chain release factor (RF) closely resembled that of WRS. Further investigation, however, suggests that the DNA encoding RF was wrongly identified and in fact encodes a rabbit WRS subunit. Other hypotheses on the interferon-inducibility of WRS, including the possibility that the protein performs other, regulatory functions in addition to its core enzymic activity, remain to be explored.
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35
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Abstract
Aminoacyl-tRNA synthetases of higher organisms are far less studied compared to their prokaryotic and unicellular eukaryotic counterparts. However, many aminoacyl-tRNA synthetases from multi-cellular organisms exhibit certain features not yet described for the same enzymes of bacteria or yeast. Tryptophanyl-tRNA synthetases (TrpRS) are among the most thoroughly studied mammalian enzymes of this group. TrpRS are Zn(2+)-dependent, dimeric, class I aminoacyl-tRNA synthetases with known amino acid sequence for four different mammalian orders. TrpRS is not associated in a stable multi-synthetase complex, although it exhibits a long N-terminal extension absent from bacterial TrpRS. The human gene encoding TrpRS belongs to the interferon-responsive gene family and TrpRS activity drastically increases after interferon gamma induction. For unknown reasons TrpRS is overproduced in pancreas of Ruminantia. Other data on TrpRS available so far are summarized and briefly discussed here.
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Affiliation(s)
- L L Kisselev
- Engelhardt Institute of Molecular Biology, Moscow, Russia
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