1
|
Patil SS, Panchal V, Røstbø T, Romanyuk S, Hollås H, Brenk R, Grindheim AK, Vedeler A. RNA-binding is an ancient trait of the Annexin family. Front Cell Dev Biol 2023; 11:1161588. [PMID: 37397259 PMCID: PMC10311354 DOI: 10.3389/fcell.2023.1161588] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 05/25/2023] [Indexed: 07/04/2023] Open
Abstract
Introduction: The regulation of intracellular functions in mammalian cells involves close coordination of cellular processes. During recent years it has become evident that the sorting, trafficking and distribution of transport vesicles and mRNA granules/complexes are closely coordinated to ensure effective simultaneous handling of all components required for a specific function, thereby minimizing the use of cellular energy. Identification of proteins acting at the crossroads of such coordinated transport events will ultimately provide mechanistic details of the processes. Annexins are multifunctional proteins involved in a variety of cellular processes associated with Ca2+-regulation and lipid binding, linked to the operation of both the endocytic and exocytic pathways. Furthermore, certain Annexins have been implicated in the regulation of mRNA transport and translation. Since Annexin A2 binds specific mRNAs via its core structure and is also present in mRNP complexes, we speculated whether direct association with RNA could be a common property of the mammalian Annexin family sharing a highly similar core structure. Methods and results: Therefore, we performed spot blot and UV-crosslinking experiments to assess the mRNA binding abilities of the different Annexins, using annexin A2 and c-myc 3'UTRs as well as c-myc 5'UTR as baits. We supplemented the data with immunoblot detection of selected Annexins in mRNP complexes derived from the neuroendocrine rat PC12 cells. Furthermore, biolayer interferometry was used to determine the KD of selected Annexin-RNA interactions, which indicated distinct affinities. Amongst these Annexins, Annexin A13 and the core structures of Annexin A7, Annexin A11 bind c-myc 3'UTR with KDs in the nanomolar range. Of the selected Annexins, only Annexin A2 binds the c-myc 5'UTR indicating some selectivity. Discussion: The oldest members of the mammalian Annexin family share the ability to associate with RNA, suggesting that RNA-binding is an ancient trait of this protein family. Thus, the combined RNA- and lipid-binding properties of the Annexins make them attractive candidates to participate in coordinated long-distance transport of membrane vesicles and mRNAs regulated by Ca2+. The present screening results can thus pave the way for studies of the multifunctional Annexins in a novel cellular context.
Collapse
Affiliation(s)
- Sudarshan S. Patil
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Vipul Panchal
- Biorecognition Unit, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Trude Røstbø
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Sofya Romanyuk
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Hanne Hollås
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Ruth Brenk
- Biorecognition Unit, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Ann Kari Grindheim
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Anni Vedeler
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| |
Collapse
|
2
|
Grindheim AK, Patil SS, Nebigil CG, Désaubry L, Vedeler A. The flavagline FL3 interferes with the association of Annexin A2 with the eIF4F initiation complex and transiently stimulates the translation of annexin A2 mRNA. Front Cell Dev Biol 2023; 11:1094941. [PMID: 37250892 PMCID: PMC10214161 DOI: 10.3389/fcell.2023.1094941] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 04/28/2023] [Indexed: 05/31/2023] Open
Abstract
Introduction: Annexin A2 (AnxA2) plays a critical role in cell transformation, immune response, and resistance to cancer therapy. Besides functioning as a calcium- and lipidbinding protein, AnxA2 also acts as an mRNA-binding protein, for instance, by interacting with regulatory regions of specific cytoskeleton-associated mRNAs. Methods and Results: Nanomolar concentrations of FL3, an inhibitor of the translation factor eIF4A, transiently increases the expression of AnxA2 in PC12 cells and stimulates shortterm transcription/translation of anxA2 mRNA in the rabbit reticulocyte lysate. AnxA2 regulates the translation of its cognate mRNA by a feed-back mechanism, which can partly be relieved by FL3. Results obtained using the holdup chromatographic retention assay results suggest that AnxA2 interacts transiently with eIF4E (possibly eIF4G) and PABP in an RNA-independent manner while cap pulldown experiments indicate a more stable RNA-dependent interaction. Short-term (2 h) treatment of PC12 cells with FL3 increases the amount of eIF4A in cap pulldown complexes of total lysates, but not of the cytoskeletal fraction. AnxA2 is only present in cap analogue-purified initiation complexes from the cytoskeletal fraction and not total lysates confirming that AnxA2 binds to a specific subpopulation of mRNAs. Discussion: Thus, AnxA2 interacts with PABP1 and subunits of the initiation complex eIF4F, explaining its inhibitory effect on translation by preventing the formation of the full eIF4F complex. This interaction appears to be modulated by FL3. These novel findings shed light on the regulation of translation by AnxA2 and contribute to a better understanding of the mechanism of action of eIF4A inhibitors.
Collapse
Affiliation(s)
- Ann Kari Grindheim
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Sudarshan S. Patil
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Canan G. Nebigil
- Regenerative Nanomedicine Laboratory (UMR1260), Faculty of Medicine, FMTS, INSERM-University of Strasbourg, Strasbourg, France
| | - Laurent Désaubry
- Regenerative Nanomedicine Laboratory (UMR1260), Faculty of Medicine, FMTS, INSERM-University of Strasbourg, Strasbourg, France
| | - Anni Vedeler
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| |
Collapse
|
3
|
Strand E, Hollås H, Sakya SA, Romanyuk S, Saraste MEV, Grindheim AK, Patil SS, Vedeler A. Annexin A2 binds the internal ribosomal entry site of c- myc mRNA and regulates its translation. RNA Biol 2021; 18:337-354. [PMID: 34346292 PMCID: PMC8677036 DOI: 10.1080/15476286.2021.1947648] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The expression and localization of the oncoprotein c-Myc is highly regulated at the level of transcription, mRNA transport, translation, as well as stability of the protein. We previously showed that Annexin A2 (AnxA2) binds to a specific localization element in the 3'untranslated region (UTR) of c-myc mRNA and is involved in its localization to the perinuclear region. In the present study, we demonstrate that AnxA2 binds in a Ca2+-dependent manner to the internal ribosomal entry site (IRES) containing two pseudo-knots in the 5´UTR of the c-myc mRNA. Here, we employ an in vitro rabbit reticulocyte lysate system with chimeric c-myc reporter mRNAs to demonstrate that binding of AnxA2 to the c-myc IRES modulates the expression of c-Myc. Notably, we show that low levels of AnxA2 appear to increase, while high levels of AnxA2 inhibits translation of the chimeric mRNA. However, when both the AnxA2-binding site and the ribosomal docking site in the c-myc IRES are deleted, AnxA2 has no effect on the translation of the reporter mRNA. Forskolin-treatment of PC12 cells results in upregulation of Ser25 phosphorylated AnxA2 expression while c-Myc expression is down-regulated. The effect of forskolin on c-Myc expression and the level of Ser25 phosphorylated AnxA2 was abolished in the presence of EGTA. These findings indicate that AnxA2 regulates both the transport and subsequent translation of the c-myc mRNA, possibly by silencing the mRNA during its transport. They also suggest that AnxA2 act as a switch to turn off the c-myc IRES activity in the presence of calcium.Abbreviations: AnxA2, Annexin A2; β2--µglob, β2-microglobulin; cpm, counts per minute; hnRNP, heterogenous nuclear ribonucleoprotein; IRES, internal ribosomal entry site; ITAF, IRES trans-acting factor; MM, multiple myeloma; PABP, poly(A)-binding protein; PCBP, poly(rC) binding protein; PSF, PTB-associated splicing factor; PTB, polypyrimidine tract binding protein; RRL, rabbit reticulocyte lysate; UTR, untranslated region; YB, Y-box binding protein.
Collapse
Affiliation(s)
- Elin Strand
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Department of Immunology and Transfusion Medicine, Haukeland University Hospital, Bergen, Norway
| | - Hanne Hollås
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Siri Aastedatter Sakya
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Department of Pharmacology, Institute of Clinical Medicine, University of Oslo, Norway
| | - Sofya Romanyuk
- Department of Biomedicine, University of Bergen, Bergen, Norway.,City Hospital №40, St. Petersburg, Russia
| | - Mikko E V Saraste
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Quality Control Unit, Thermo Fisher Scientific - Life Technologies, Lillestrøm, Norway
| | | | | | - Anni Vedeler
- Department of Biomedicine, University of Bergen, Bergen, Norway
| |
Collapse
|
4
|
The neural ELAVL protein HuB enhances endogenous proto-oncogene activation. Biochem Biophys Res Commun 2019; 517:330-337. [PMID: 31358321 DOI: 10.1016/j.bbrc.2019.07.089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 07/23/2019] [Indexed: 02/06/2023]
Abstract
The cytoplasmic distribution of the HuR/ELAVL1 (embryonic lethal abnormal vision 1) protein is recognized as an important prognostic factor of malignant tumors. However, the previous study suggests that exogenous over-expression of HuR is not sufficient for nuclear export. Conversely, the predominantly cytosolic distribution of neuron-specific human ELAV members, including HuB/ELAVL2, HuC/ELAVL3, and HuD/ELAVL4, has been reported. In the present study, we demonstrated the expression of HuB in several types of cancer cells, but expression of HuC and HuD was not observed. In addition, our results indicated that HuR and HuB formed a complex in the cytosolic fraction of cancer cells via the RRM3 region. Ectopic expression of HuB was capable of initiating the cytosolic translocation of HuR from the nucleus to the cytosol. Furthermore, HuB-transduced cancer cells displayed significant nuclear export of HuR, with quantitative PCR experiments revealing the simultaneous upregulation of HIF-1α, c-Fos, c-MYC, and Ets2 basal mRNA expression. Phorbol 12-myristate 13-acetate (PMA)-stimulated HuB-transduced cells demonstrated significantly enhanced activation of endogenous c-Fos and CREB dependent cascades. Finally, co-transfection of HuB with the E1 region of type 5 human adenovirus significantly enhanced E1 transformation activities but that of HuR with the E1 region did not. Collectively, our findings suggest that the neural Hu family protein HuB plays a major role in the activation of memory-related proto-oncogenes.
Collapse
|
5
|
O’Leary CA, Andrews RJ, Tompkins VS, Chen JL, Childs-Disney JL, Disney MD, Moss WN. RNA structural analysis of the MYC mRNA reveals conserved motifs that affect gene expression. PLoS One 2019; 14:e0213758. [PMID: 31206539 PMCID: PMC6576772 DOI: 10.1371/journal.pone.0213758] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/30/2019] [Indexed: 12/15/2022] Open
Abstract
The MYC gene encodes a human transcription factor and proto-oncogene that is dysregulated in over half of all known cancers. To better understand potential post-transcriptional regulatory features affecting MYC expression, we analyzed secondary structures in the MYC mRNA using a program that is optimized for finding small locally-folded motifs with a high propensity for function. This was accomplished by calculating folding metrics across the MYC sequence using a sliding analysis window and generating unique consensus base pairing models weighted by their lower-than-random predicted folding energy. A series of 30 motifs were identified, primarily in the 5' and 3' untranslated regions, which show evidence of structural conservation and compensating mutations across vertebrate MYC homologs. This analysis was able to recapitulate known elements found within an internal ribosomal entry site, as well as discover a novel element in the 3' UTR that is unusually stable and conserved. This novel motif was shown to affect MYC expression, potentially via the modulation of miRNA target accessibility or other trans-regulatory factors. In addition to providing basic insights into mechanisms that regulate MYC expression, this study provides numerous, potentially druggable RNA targets for the MYC gene, which is considered “undruggable” at the protein level.
Collapse
Affiliation(s)
- Collin A. O’Leary
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, United States of America
| | - Ryan J. Andrews
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, United States of America
| | - Van S. Tompkins
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, United States of America
| | - Jonathan L. Chen
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, United States of America
| | | | - Matthew D. Disney
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, United States of America
| | - Walter N. Moss
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, United States of America
- * E-mail:
| |
Collapse
|
6
|
Santos-Valencia JC, Cancio-Lonches C, Trujillo-Uscanga A, Alvarado-Hernández B, Lagunes-Guillén A, Gutiérrez-Escolano AL. Annexin A2 associates to feline calicivirus RNA in the replication complexes from infected cells and participates in an efficient viral replication. Virus Res 2018; 261:1-8. [PMID: 30543874 DOI: 10.1016/j.virusres.2018.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 12/07/2018] [Accepted: 12/08/2018] [Indexed: 01/27/2023]
Abstract
Cellular proteins have been identified to participate in calicivirus replication in association with viral proteins and/or viral RNAs. By mass spectrometry from pull-down assays, we identified several cellular proteins bound to the feline calicivirus (FCV) genomic RNA; among them the lipid raft-associated scaffold protein Annexin (Anx) A2. AnxA2 colocalizes with FCV NS6/7 protein and with the dsRNA in infected cells; moreover, it was found associated with the viral RNA in the membrane fraction corresponding to the replication complexes (RCs), suggesting its role during FCV replication. AnxA2-knockdown from CrFK cells prior to infection with FCV caused a delay in the cytopathic effect, a strong reduction of viral non-structural proteins and dsRNA production, and a decrease of FCV yield in both cell-associated and supernatant fractions. Taken together, these results indicate that AnxA2 associates to the genomic RNA of FCV and is required for an efficient FCV replication.
Collapse
Affiliation(s)
- Juan Carlos Santos-Valencia
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | - Clotilde Cancio-Lonches
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | - Adrian Trujillo-Uscanga
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | - Beatriz Alvarado-Hernández
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | - Anel Lagunes-Guillén
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | - Ana Lorena Gutiérrez-Escolano
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico.
| |
Collapse
|
7
|
Wegener M, Müller-McNicoll M. Nuclear retention of mRNAs - quality control, gene regulation and human disease. Semin Cell Dev Biol 2017; 79:131-142. [PMID: 29102717 DOI: 10.1016/j.semcdb.2017.11.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 12/21/2022]
Abstract
Nuclear retention of incompletely spliced or mature mRNAs emerges as a novel, previously underappreciated layer of gene regulation, which enables the cell to rapidly respond to stress, viral infection, differentiation cues or changing environmental conditions. Focusing on mammalian cells, we discuss recent insights into the mechanisms and functions of nuclear retention, describe retention-promoting features in protein-coding transcripts and propose mechanisms for their regulated release into the cytoplasm. Moreover, we discuss examples of how aberrant nuclear retention of mRNAs may lead to human diseases.
Collapse
Affiliation(s)
- Marius Wegener
- RNA Regulation Group, Cluster of Excellence 'Macromolecular Complexes', Goethe University Frankfurt, Institute of Cell Biology and Neuroscience, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany
| | - Michaela Müller-McNicoll
- RNA Regulation Group, Cluster of Excellence 'Macromolecular Complexes', Goethe University Frankfurt, Institute of Cell Biology and Neuroscience, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany.
| |
Collapse
|
8
|
Bargi-Souza P, Goulart-Silva F, Nunes MT. Novel aspects of T 3 actions on GH and TSH synthesis and secretion: physiological implications. J Mol Endocrinol 2017; 59:R167-R178. [PMID: 28951438 DOI: 10.1530/jme-17-0068] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 09/26/2017] [Indexed: 12/27/2022]
Abstract
Thyroid hormones (THs) classically regulate the gene expression by transcriptional mechanisms. In pituitary, the encoding genes for growth hormone (GH) and thyroid-stimulating hormone (TSH) are examples of genes regulated by triiodothyronine (T3) in a positive and negative way, respectively. Recent studies have shown a rapid adjustment of GH and TSH synthesis/secretion induced by T3 posttranscriptional actions. In somatotrophs, T3 promotes an increase in Gh mRNA content, poly(A) tail length and binding to the ribosome, associated with a rearrangement of actin cytoskeleton. In thyrotrophs, T3 reduces Tshb mRNA content, poly(A) tail length and its association with the ribosome. In parallel, it promotes a redistribution of TSH secretory granules to more distal regions of the cell periphery, indicating a rapid effect of T3 inhibition of TSH secretion. T3 was shown to affect the content of tubulin and the polymerization of actin and tubulin cytoskeletons in the whole anterior pituitary gland, and to increase intracellular alpha (CGA) content. This review summarizes genomic and non-genomic/posttranscriptional actions of TH on the regulation of several steps of GH and TSH synthesis and secretion. These distinct mechanisms induced by T3 can occur simultaneously, even though non-genomic effects are promptly elicited and precede the genomic actions, coexisting in a functional network within the cells.
Collapse
Affiliation(s)
| | | | - M T Nunes
- Department of Physiology and Biophysics of the Institute of Biomedical SciencesUniversity of São Paulo, São Paulo, SP, Brazil
| |
Collapse
|
9
|
Aukrust I, Rosenberg LA, Ankerud MM, Bertelsen V, Hollås H, Saraste J, Grindheim AK, Vedeler A. Post-translational modifications of Annexin A2 are linked to its association with perinuclear nonpolysomal mRNP complexes. FEBS Open Bio 2017; 7:160-173. [PMID: 28174683 PMCID: PMC5292671 DOI: 10.1002/2211-5463.12173] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/03/2016] [Accepted: 11/23/2016] [Indexed: 01/20/2023] Open
Abstract
Various post‐translational modifications (PTMs) regulate the localisation and function of the multifunctional protein Annexin A2 (AnxA2). In addition to its various tasks as a cytoskeletal‐ and membrane‐associated protein, AnxA2 can function as a trans‐acting protein binding to cis‐acting sequences of specific mRNAs. In the present study, we have examined the role of Ser25 phosphorylation in subcellular localisation of AnxA2 and its interaction with mRNP complexes. Subcellular fractionation and confocal microscopy of rat neuroendocrine PC12 cells showed that Ser25‐phosphorylated AnxA2 (pSer25AnxA2) is absent from the nucleus and mainly localised to the perinuclear region, evidently associating with both membranes and cytoskeletal elements. Perinuclear targeting of AnxA2 was abolished by inhibition of protein kinase C activity, which resulted in cortical enrichment of the protein. Although oligo(dT)‐affinity purification of mRNAs revealed that pSer25AnxA2 associates with nonpolysomal, translationally inactive mRNP complexes, it displayed only partial overlap with a marker of P‐bodies. The phosphorylated protein is present as high‐molecular‐mass forms, indicating that it contains additional covalent PTMs, apparently triggered by its Ser25 phosphorylation. The subcellular distributions of these forms clearly differ from the main form of AnxA2 and are also distinct from that of Tyr23‐phosphorylated AnxA2. Immunoprecipitation verified that these high‐molecular‐mass forms are due to ubiquitination and/or sumoylation. Moreover, these results indicate that Ser25 phosphorylation and ubiquitin/SUMO1 conjugation of AnxA2 promote its association with nonpolysomal mRNAs, providing evidence of a possible mechanism to sequester a subpopulation of mRNAs in a translationally inactive and transport competent form at a distinct subcellular localisation.
Collapse
Affiliation(s)
- Ingvild Aukrust
- Department of Biomedicine University of Bergen Norway; Present address: Centre for Medical Genetics and Molecular Medicine Haukeland University Hospital Bergen Norway
| | | | | | - Vibeke Bertelsen
- Department of Biomedicine University of Bergen Norway; Present address: Department of Pathology Oslo University Hospital University of Oslo Oslo Norway
| | - Hanne Hollås
- Department of Biomedicine University of Bergen Norway
| | - Jaakko Saraste
- Department of Biomedicine University of Bergen Norway; Molecular Imaging Centre (MIC) University of Bergen Norway
| | - Ann Kari Grindheim
- Department of Biomedicine University of Bergen Norway; Molecular Imaging Centre (MIC) University of Bergen Norway
| | - Anni Vedeler
- Department of Biomedicine University of Bergen Norway
| |
Collapse
|
10
|
Kannaiah S, Amster-Choder O. Protein targeting via mRNA in bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1457-65. [PMID: 24263243 DOI: 10.1016/j.bbamcr.2013.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 11/09/2013] [Accepted: 11/11/2013] [Indexed: 01/10/2023]
Abstract
Proteins of all living organisms must reach their subcellular destination to sustain the cell structure and function. The proteins are transported to one of the cellular compartments, inserted into the membrane, or secreted across the membrane to the extracellular milieu. Cells have developed various mechanisms to transport proteins across membranes, among them localized translation. Evidence for targeting of Messenger RNA for the sake of translation of their respective protein products at specific subcellular sites in many eukaryotic model organisms have been accumulating in recent years. Cis-acting RNA localizing elements, termed RNA zip-codes, which are embedded within the mRNA sequence, are recognized by RNA-binding proteins, which in turn interact with motor proteins, thus coordinating the intracellular transport of the mRNA transcripts. Despite the rareness of conventional organelles, first and foremost a nucleus, pieces of evidence for mRNA localization to specific subcellular domains, where their protein products function, have also been obtained for prokaryotes. Although the underlying mechanisms for transcript localization in bacteria are yet to be unraveled, it is now obvious that intracellular localization of mRNA is a common mechanism to spatially localize proteins in both eukaryotes and prokaryotes. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
Collapse
Affiliation(s)
- Shanmugapriya Kannaiah
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University - Faculty of Medicine, P.O.Box 12272, Jerusalem 91120, Israel
| | - Orna Amster-Choder
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University - Faculty of Medicine, P.O.Box 12272, Jerusalem 91120, Israel.
| |
Collapse
|
11
|
The role of translation initiation regulation in haematopoiesis. Comp Funct Genomics 2012; 2012:576540. [PMID: 22649283 PMCID: PMC3357504 DOI: 10.1155/2012/576540] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 02/25/2012] [Indexed: 02/06/2023] Open
Abstract
Organisation of RNAs into functional subgroups that are translated in response to extrinsic and intrinsic factors underlines a relatively unexplored gene expression modulation that drives cell fate in the same manner as regulation of the transcriptome by transcription factors. Recent studies on the molecular mechanisms of inflammatory responses and haematological disorders indicate clearly that the regulation of mRNA translation at the level of translation initiation, mRNA stability, and protein isoform synthesis is implicated in the tight regulation of gene expression. This paper outlines how these posttranscriptional control mechanisms, including control at the level of translation initiation factors and the role of RNA binding proteins, affect hematopoiesis. The clinical relevance of these mechanisms in haematological disorders indicates clearly the potential therapeutic implications and the need of molecular tools that allow measurement at the level of translational control. Although the importance of miRNAs in translation control is well recognised and studied extensively, this paper will exclude detailed account of this level of control.
Collapse
|
12
|
Manojlovic Z, Stefanovic B. A novel role of RNA helicase A in regulation of translation of type I collagen mRNAs. RNA (NEW YORK, N.Y.) 2012; 18:321-34. [PMID: 22190748 PMCID: PMC3264918 DOI: 10.1261/rna.030288.111] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 11/04/2011] [Indexed: 05/30/2023]
Abstract
Type I collagen is composed of two α1(I) polypeptides and one α2(I) polypeptide and is the most abundant protein in the human body. Expression of type I collagen is primarily controlled at the level of mRNA stability and translation. Coordinated translation of α(I) and α2(I) mRNAs is necessary for efficient folding of the corresponding peptides into the collagen heterotrimer. In the 5' untranslated region (5' UTR), collagen mRNAs have a unique 5' stem-loop structure (5' SL). La ribonucleoprotein domain family member 6 (LARP6) is the protein that binds 5' SL with high affinity and specificity and coordinates their translation. Here we show that RNA helicase A (RHA) is tethered to the 5' SL of collagen mRNAs by interaction with the C-terminal domain of LARP6. In vivo, collagen mRNAs immunoprecipitate with RHA in an LARP6-dependent manner. Knockdown of RHA prevents formation of polysomes on collagen mRNAs and dramatically reduces synthesis of collagen protein, without affecting the level of the mRNAs. A reporter mRNA with collagen 5' SL is translated three times more efficiently in the presence of RHA than the same reporter without the 5' SL, indicating that the 5' SL is the cis-acting element conferring the regulation. During activation of quiescent cells into collagen-producing cells, expression of RHA is highly up-regulated. We postulate that RHA is recruited to the 5' UTR of collagen mRNAs by LARP6 to facilitate their translation. Thus, RHA has been discovered as a critical factor for synthesis of the most abundant protein in the human body.
Collapse
Affiliation(s)
- Zarko Manojlovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
| | - Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
| |
Collapse
|
13
|
Cheneval D, Kastelic T, Fuerst P, Parker CN. A Review of Methods to Monitor the Modulation of mRNA Stability. ACTA ACUST UNITED AC 2010; 15:609-22. [DOI: 10.1177/1087057110365897] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Posttranscriptional regulation of gene expression is an elaborate and intricate process, constituting an important mechanism for the control of protein expression. During its existence, mRNA is escorted by proteins and other RNAs, which control the maturation, transportation, localization, translational efficiency, and ultimately its degradation. Without changes at the transcription level, mRNA steady-state levels can vary dramatically by just small changes in mRNA stability. By influencing the metabolism of specific mRNAs, the abundance of specific mRNAs can be controlled in organisms from bacteria to mammals. In eukaryotic cells, the control of mRNA stability is exerted through specific cis-acting elements (sequence-specific control elements) and trans-acting factors (mRNA binding proteins and some miRNAs). mRNA stability appears to be a key regulator in controlling the expression of many proteins. Dysregulation of mRNA stability has been associated with human diseases, including cancer, inflammatory disease, and Alzheimer’s. These observations suggest that modulating the stability of specific mRNAs may represent a viable strategy for pharmaceutical intervention. The literature already describes several compounds that influence mRNA stability. Measuring mRNA stability by conventional methods is labor intensive and time-consuming. However, several systems have been described that can be used to screen for modulators of mRNA levels in a high-throughput format. Thus, these assay systems offer a novel approach for screening targets that at present appear to be poorly “drugable.” This review describes the utility of mRNA stability as a novel approach to drug discovery, focusing on assay methods and tool compounds available to monitor mRNA stability. The authors describe mRNA stability assays and issues related to this approach.
Collapse
Affiliation(s)
| | | | - Peter Fuerst
- Novartis Pharma AG, Novartis Institute for BioMedical Research, Center for Proteomic Chemistry, Basel, Switzerland
| | - Christian N. Parker
- Novartis Pharma AG, Novartis Institute for BioMedical Research, Center for Proteomic Chemistry, Basel, Switzerland
| |
Collapse
|
14
|
Dierssen JWF, van Puijenbroek M, Dezentjé DA, Fleuren GJ, Cornelisse CJ, van Wezel T, Offringa R, Morreau H. Frequent mutations in the 3'-untranslated region of IFNGR1 lack functional impairment in microsatellite-unstable colorectal tumours. Eur J Hum Genet 2008; 16:1235-9. [PMID: 18414508 DOI: 10.1038/ejhg.2008.81] [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: 01/03/2023] Open
Abstract
Microsatellite repeats are frequently found to be mutated in microsatellite-instable colorectal tumours. This suggests that these mutations are important events during tumour development. We have observed frequent mutations in microsatellite-instable (MSI-H) tumours and cell lines of a conserved A14 repeat within the 3'-untranslated region of the interferon-gamma receptor 1 gene (IFNGR1). The repeat was mutated in 59% (41 of 70) of colon carcinomas and in all four MSI-H colon cancer cell lines tested. In-vitro analysis of these cell lines did not show a decreased responsiveness to standard IFNgamma concentrations when compared to microsatellite-stable colon cancer cell lines. A functional consequence of the frequently found microsatellite instability in IFNGR1 is therefore not evident.
Collapse
|
15
|
Hau HH, Walsh RJ, Ogilvie RL, Williams DA, Reilly CS, Bohjanen PR. Tristetraprolin recruits functional mRNA decay complexes to ARE sequences. J Cell Biochem 2007; 100:1477-92. [PMID: 17133347 DOI: 10.1002/jcb.21130] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
AU-rich elements (AREs) in the 3' untranslated region (UTR) of numerous mammalian transcripts function as instability elements that promote rapid mRNA degradation. Tristetraprolin (TTP) is an ARE-binding protein that promotes rapid mRNA decay through mechanisms that are poorly understood. A 31 nucleotide ARE sequences from the TNF-alpha 3' UTR promoted TTP-dependent mRNA decay when it was inserted into the 3' UTR of a beta-globin reporter transcript, indicating that this short sequence was sufficient for TTP function. We used a gel shift assay to identify a TTP-containing complex in cytoplasmic extracts from TTP-transfected HeLa cells that bound specifically to short ARE sequences. This TTP-containing complex also contained the 5'-3' exonuclease Xrn1 and the exosome component PM-scl75 because it was super-shifted with anti-Xrn1 or anti-PMscl75 antibodies. RNA affinity purification verified that these proteins associated specifically with ARE sequences in a TTP-dependent manner. Using a competition binding assay, we found that the TTP-containing complex bound with high affinity to short ARE sequences from GM-CSF, IL-3, TNF-alpha, IL-2, and c-fos, but did not bind to a U-rich sequence from c-myc, a 22 nucleotide poly U sequence or a mutated GM-CSF control sequence. High affinity binding by the TTP-containing complex correlated with TTP-dependent deadenylation and decay of capped, polyadenylated transcripts in a cell-free mRNA decay assay, suggesting that the TTP-containing complex was functional. These data support a model whereby TTP functions to enhance mRNA decay by recruiting components of the cellular mRNA decay machinery to the transcript.
Collapse
Affiliation(s)
- Heidi H Hau
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | | | | | | | | | | |
Collapse
|
16
|
Du TG, Schmid M, Jansen RP. Why cells move messages: the biological functions of mRNA localization. Semin Cell Dev Biol 2007; 18:171-7. [PMID: 17398125 DOI: 10.1016/j.semcdb.2007.01.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
RNA localization is a widespread mechanism that allows cells to spatially control protein function by determining their sites of synthesis. In embryos, localized mRNAs are involved in morphogen gradient formation or the asymmetric distribution of cell fate determinants. In somatic cell types, mRNA localization contributes to local assembly of protein complexes or facilitates protein targeting to organelles. Long-distance transport of specific mRNAs in plants allows coordination of developmental processes between different plant organs. In this review, we will discuss the biological significance of different patterns of mRNA localization.
Collapse
Affiliation(s)
- Tung-Gia Du
- Department of Chemistry and Biochemistry, Gene Center, Ludwig-Maximilians-University Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | | | | |
Collapse
|
17
|
Hollås H, Aukrust I, Grimmer S, Strand E, Flatmark T, Vedeler A. Annexin A2 recognises a specific region in the 3'-UTR of its cognate messenger RNA. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1325-34. [PMID: 17045350 DOI: 10.1016/j.bbamcr.2006.08.043] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 08/17/2006] [Accepted: 08/26/2006] [Indexed: 12/28/2022]
Abstract
Annexin A2 is a multifunctional Ca(2+)- and lipid-binding protein. We previously showed that a distinct pool of cellular Annexin A2 associates with mRNP complexes or polysomes associated with the cytoskeleton. Here we report in vitro and in vivo experiments showing that Annexin A2 present in this subset of mRNP complexes interacts with its cognate mRNA and c-myc mRNA, but not with beta(2)-microglobulin mRNA translated on membrane-bound polysomes. The protein recognises sequence elements within the untranslated regions, but not within the coding region, of its cognate mRNA. Alignment of the Annexin A2-binding 3'-untranslated regions of annexin A2 mRNA from several species reveals a five nucleotide consensus sequence 5'-AA(C/G)(A/U)G. The Annexin A2-interacting region of the 3'-untranslated region can be mapped to a sequence of about 100 nucleotides containing two repeats of the consensus sequence. The binding elements appear to involve both single and double stranded regions, indicating that a specific higher order mRNA structure is required for binding to Annexin A2. We suggest that this type of interaction is representative for a group of mRNAs translated on cytoskeleton-bound polysomes.
Collapse
Affiliation(s)
- Hanne Hollås
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway
| | | | | | | | | | | |
Collapse
|
18
|
Russo A, Russo G, Cuccurese M, Garbi C, Pietropaolo C. The 3'-untranslated region directs ribosomal protein-encoding mRNAs to specific cytoplasmic regions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:833-43. [PMID: 16839621 DOI: 10.1016/j.bbamcr.2006.05.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 04/21/2006] [Accepted: 05/10/2006] [Indexed: 11/30/2022]
Abstract
mRNA localization is a conserved post-transcriptional process crucial for a variety of systems. We have analyzed the subcellular distribution of mRNAs encoding human cytosolic and mitochondrial ribosomal proteins. Biochemical fractionation experiments showed that the transcripts for cytosolic ribosomal proteins associate preferentially with the cytoskeleton via actin microfilaments. Transfection in HeLa cells of a GFP reporter construct containing the cytosolic ribosomal protein L4 3'-UTR showed that the 3'-UTR is necessary for the association of the transcript to the cytoskeleton. Using confocal analysis we demonstrate that the chimeric transcript is specifically associated with the perinuclear cytoskeleton. We also show that mRNA for mitochondrial ribosomal protein S12 is asymmetrically distributed in the cytoplasm. In fact, this transcript was localized mainly in the proximity of mitochondria, and the localization was 3'-UTR-dependent. In summary, ribosomal protein mRNAs constitute a new class of localized transcripts that share a common localization mechanism.
Collapse
Affiliation(s)
- Annapina Russo
- Dipartimento di Biochimica e Biotecnologie Mediche, Università Federico II, Via Sergio Pansini 5, Napoli 80131, Italy
| | | | | | | | | |
Collapse
|
19
|
Chabanon H, Mickleburgh I, Burtle B, Pedder C, Hesketh J. An AU-rich stem-loop structure is a critical feature of the perinuclear localization signal of c-myc mRNA. Biochem J 2006; 392:475-83. [PMID: 16042622 PMCID: PMC1316286 DOI: 10.1042/bj20050812] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In eukaryotic cells, several mRNAs including those of c-myc and c-fos are localized to the perinuclear cytoplasm and associated with the cytoskeleton. The localization element of c-myc mRNA is present within its 3'UTR (3'-untranslated region) but the precise nature of this signal has remained unidentified. Chemical/enzymatic cleavage with RNases (ribonucleases) and lead have identified single-stranded and double-stranded regions in RNA transcripts of nucleotides 194-280 of the c-myc 3'UTR. Combined with computer predicted structure these results indicate that this region folds so that part of it forms a stem-loop structure. A mutation, that has been previously shown to prevent localization, leads to a different secondary RNA structure in this region as indicated by altered cleavage patterns. Competitive gel-retardation assays, using labelled transcripts corresponding to nucleotides 205-280 of c-myc 3'UTR, and fibroblast extracts revealed that the stem-loop region was sufficient for RNA-protein complex formation. In situ hybridization studies in cells transfected with reporter constructs, in which all or parts of the region corresponding to this stem-loop were linked to beta-globin, indicated that this region was sufficient for localization and that deletion of the nucleotides corresponding to the proposed upper-stem or terminal loop prevented localization. Our hypothesis is that an AU-rich stem-loop structure within nt 222-267 in the c-myc 3'UTR forms the perinuclear localization signal. Bioinformatic analysis suggests that this signal shares features with 3'UTRs of other localized mRNAs and that these features may represent a conserved form of signal in mRNA localization mechanisms.
Collapse
Affiliation(s)
- Hervé Chabanon
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle-upon-Tyne NE2 4HH, U.K
| | - Ian Mickleburgh
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle-upon-Tyne NE2 4HH, U.K
| | - Brian Burtle
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle-upon-Tyne NE2 4HH, U.K
| | - Christopher Pedder
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle-upon-Tyne NE2 4HH, U.K
| | - John Hesketh
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle-upon-Tyne NE2 4HH, U.K
- To whom correspondence should be addressed (email )
| |
Collapse
|
20
|
Nury D, Chabanon H, Levadoux-Martin M, Hesketh J. An eleven nucleotide section of the 3'-untranslated region is required for perinuclear localization of rat metallothionein-1 mRNA. Biochem J 2005; 387:419-28. [PMID: 15537387 PMCID: PMC1134970 DOI: 10.1042/bj20040630] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Localization of mRNAs provides a novel mechanism for synthesis of proteins close to their site of function. MT1 (metallothionein-1) is a small, metal-binding protein that is largely cytoplasmic but which can be found in the nucleus. The localization of rat MT1 requires the perinuclear localization of its mRNA by a mechanism dependent on the 3'-UTR (3'-untranslated region). The present study investigates the nature of this mRNA localization signal using Chinese-hamster ovary cells transfected with gene constructs in which either MT1 or the globin coding region is linked to different sequences from the MT1 3'-UTR. Deletion, mutagenesis and antisense oligonucleotide approaches indicate that nt 45-76 of the 3'-UTR, in particular nt 66-76, are required for the localization of either MT1 mRNA or chimaeric transcripts in which a beta-globin coding region is linked to sequences from the MT1 3'-UTR. This section of the 3'-UTR contains a CACC repeat. Two mutations that are predicted to alter the secondary structure of this region also impair localization. Our hypothesis is that the perinuclear localization signal in MT1 mRNA is formed by a combination of the CACC repeat and its structural context.
Collapse
Affiliation(s)
- David Nury
- School of Cell and Molecular Biosciences, Faculty of Medicine, University of Newcastle, Newcastle upon Tyne NE1 7RU, U.K
| | - Hervé Chabanon
- School of Cell and Molecular Biosciences, Faculty of Medicine, University of Newcastle, Newcastle upon Tyne NE1 7RU, U.K
| | - Marilyne Levadoux-Martin
- School of Cell and Molecular Biosciences, Faculty of Medicine, University of Newcastle, Newcastle upon Tyne NE1 7RU, U.K
| | - John Hesketh
- School of Cell and Molecular Biosciences, Faculty of Medicine, University of Newcastle, Newcastle upon Tyne NE1 7RU, U.K
- To whom correspondence should be addressed (email )
| |
Collapse
|
21
|
Czaplinski K, Köcher T, Schelder M, Segref A, Wilm M, Mattaj IW. Identification of 40LoVe, a Xenopus hnRNP D family protein involved in localizing a TGF-beta-related mRNA during oogenesis. Dev Cell 2005; 8:505-15. [PMID: 15809033 DOI: 10.1016/j.devcel.2005.01.012] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2004] [Revised: 01/13/2005] [Accepted: 01/19/2005] [Indexed: 01/10/2023]
Abstract
Asymmetric distribution of cellular components underlies many biological processes, and the localization of mRNAs within domains of the cytoplasm is one important mechanism of establishing and maintaining cellular asymmetry. mRNA localization often involves assembly of large ribonucleoproteins (RNPs) in the cytoplasm. Using an RNA affinity chromatography approach, we investigated localization RNP formation on the vegetal localization element (VLE) of the mRNA encoding Vg1, a Xenopus TGF-beta family member. We identified 40LoVe, an hnRNP D family protein, as a specific VLE binding protein from Xenopus oocytes. Interaction of 40LoVe with the VLE strictly correlates with the ability of the RNA to localize, and antibodies against 40LoVe inhibit vegetal localization in vivo in oocytes. Our results associate an hnRNP D protein with mRNA localization and have implications for several functions mediated by this important protein family.
Collapse
Affiliation(s)
- Kevin Czaplinski
- EMBL Gene Expression Programme, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | | | | | | | | | | |
Collapse
|
22
|
Reddy KK, Oitomen FM, Patel GP, Bag J. Perinuclear localization of slow troponin C m RNA in muscle cells is controlled by a cis-element located at its 3' untranslated region. RNA (NEW YORK, N.Y.) 2005; 11:294-307. [PMID: 15701732 PMCID: PMC1370719 DOI: 10.1261/rna.5460105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2003] [Accepted: 12/07/2004] [Indexed: 05/24/2023]
Abstract
The process of mRNA localization within a specific cytoplasmic region is an integral aspect of the regulation of gene expression. Furthermore, colocalization of mRNAs and their respective translation products may facilitate the proper assembly of multi-subunit complexes like the thick and thin filaments of muscle. This postulate was tested by investigating the cytoplasmic localization of three mRNAs-the alpha-actin, slow troponin C (sTnC), and slow troponin I (sTnI), which encode different poly-peptide partners of the thin filament. Using in situ hybridization we showed that all three thin filament mRNAs are localized in the perinuclear cytoplasm of cultured C2C12 muscle cells. Their localization differs from that of the nonmuscle beta-actin mRNA, which is localized in the peripheral region of both proliferating nondifferentiated myoblasts and the differentiated myocytes. Analysis of the localization signal of the sTnC mRNA showed that a 40-nucleotide-long region of the sTnC mRNA 3' UTR is sufficient to confer the perinuclear localization on a heterologous reporter beta-Gal mRNA. This localization signal showed tissue specificity and worked only in the differentiated myocytes, but not in the proliferating myoblasts or in HeLa cells. The predicted secondary structure of the localization signal suggests the presence of multiple stem and loop structures in this region of the 3' UTR. Mutations within the stem region of the localization signal, which abolish the base pairing in this region, significantly reduced its perinuclear mRNA localization activity. Using UV-induced photo-cross-linking of RNA and proteins we found that a myotube-specific 42-kDa polypeptide binds to the localization signal.
Collapse
Affiliation(s)
- Kishore K Reddy
- Department of Molecular Biology and Genetics, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | | | | | | |
Collapse
|
23
|
Mickleburgh I, Burtle B, Hollås H, Campbell G, Chrzanowska-Lightowlers Z, Vedeler A, Hesketh J. Annexin A2 binds to the localization signal in the 3' untranslated region of c-myc mRNA. FEBS J 2005; 272:413-21. [PMID: 15654879 DOI: 10.1111/j.1742-4658.2004.04481.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Messenger RNA trafficking, which provides a mechanism for local protein synthesis, is dependent on cis-acting sequences in the 3' untranslated regions (3'UTRs) of the mRNAs concerned acting together with trans-acting proteins. The C-MYC transcription factor is a proto-oncogene product involved in cell proliferation, differentiation and apoptosis. Localization of c-myc mRNA to the perinuclear cytoplasm and its association with the cytoskeleton is determined by a signal in the 3'UTR. Here we show the specific binding of a trans-acting factor to the perinuclear localization element in the 3'UTR of c-myc mRNA and identify this protein as annexin A2. Gel retardation and UV cross-linking experiments showed that proteins in fibroblast extracts formed complexes with the region of c-myc 3'UTR implicated in localization; a protein of approximately 36 kDa exhibited specific, Ca(2+)-dependent binding. Binding was reduced by introduction of a mutation that abrogates localization. Using RNA-affinity columns followed by gel electrophoresis and mass spectrometry this protein was identified as annexin A2. The RNA-protein complex formed by cell extracts was further retarded by anti-(annexin A2). Purified annexin A2 bound to the same region of the c-myc 3'UTR but binding was reduced by introduction of a mutation, as with cell extracts. It is proposed that binding of annexin A2 to the localization signal in the c-myc mRNA leads to association with the cytoskeleton and perinuclear localization. The data indicate a novel functional role for the RNA-binding properties of annexin A2 in perinuclear localization of mRNA and the association with the cytoskeleton.
Collapse
Affiliation(s)
- Ian Mickleburgh
- School of Cell and Molecular Biosciences, University of Newcastle, Newcastle-upon-Tyne NE1 7RU, UK
| | | | | | | | | | | | | |
Collapse
|
24
|
Rackham O, Brown CM. Visualization of RNA-protein interactions in living cells: FMRP and IMP1 interact on mRNAs. EMBO J 2004; 23:3346-55. [PMID: 15282548 PMCID: PMC514514 DOI: 10.1038/sj.emboj.7600341] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2003] [Accepted: 07/01/2004] [Indexed: 11/09/2022] Open
Abstract
Protein expression depends significantly on the stability, translation efficiency and localization of mRNA. These qualities are largely dictated by the RNA-binding proteins associated with an mRNA. Here, we report a method to visualize and localize RNA-protein interactions in living mammalian cells. Using this method, we found that the fragile X mental retardation protein (FMRP) isoform 18 and the human zipcode-binding protein 1 ortholog IMP1, an RNA transport factor, were present on common mRNAs. These interactions occurred predominantly in the cytoplasm, in granular structures. In addition, FMRP and IMP1 interacted independently of RNA. Tethering of FMRP to an mRNA caused IMP1 to be recruited to the same mRNA and resulted in granule formation. The intimate association of FMRP and IMP1 suggests a link between mRNA transport and translational repression in mammalian cells.
Collapse
Affiliation(s)
- Oliver Rackham
- Biochemistry Department, University of Otago, Dunedin, New Zealand
| | - Chris M Brown
- Biochemistry Department, University of Otago, Dunedin, New Zealand
| |
Collapse
|
25
|
|
26
|
Hesketh JE, Villette S. Intracellular trafficking of micronutrients: from gene regulation to nutrient requirements. Proc Nutr Soc 2002; 61:405-14. [PMID: 12691169 DOI: 10.1079/pns2002176] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The intracellular distribution of micronutrients, as well as their uptake, is important for cell function. In some cases the distribution of micronutrients or their related proteins is determined by gene expression mechanisms. The 3' untranslated region (3'UTR) of metallothionein-1 mRNA determines localisation of the mRNA, and in turn intracellular trafficking of the protein product. Using transfected cells we have evidence for the trafficking of metallothionein-1 into the nucleus and for its involvement in protection from oxidative stress and DNA damage. When nutritional supply of Se is limited, selenoprotein expression is altered, but not all selenoproteins are affected equally; the available Se is prioritised for synthesis of particular selenoproteins. The prioritisation involves differences in mRNA translation and stability due to 3'UTR sequences. Potentially, genetic variation in these regulatory mechanisms may affect nutrient requirements. Genetic polymorphisms in the 3'UTR from two selenoprotein genes have been observed; one polymorphism affects selenoprotein synthesis. These examples illustrate how molecular approaches can contribute at several levels to an increased understanding of nutrient metabolism and requirements. First, they provide the tools to investigate regulatory features in genes and their products. Second, understanding these processes can provide model systems to investigate nutrient metabolism at the cellular level. Third, once key features have been identified, the availability of human genome sequence information and single nucleotide polymorphism databases present possibilities to define the extent of genetic variation in genes of nutritional relevance. Ultimately, the functionality of any variations can be defined and subgroups of the population with subtly different nutrient requirements identified.
Collapse
Affiliation(s)
- John E Hesketh
- Department of Biological and Nutritional Sciences, University of Newcastle, Newcastle-upon-Tyne NE1 7RU, UK.
| | | |
Collapse
|
27
|
Palfi A, Kortvely E, Fekete E, Kovacs B, Varszegi S, Gulya K. Differential calmodulin gene expression in the rodent brain. Life Sci 2002; 70:2829-55. [PMID: 12269397 DOI: 10.1016/s0024-3205(02)01544-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Apparently redundant members of the calmodulin (CaM) gene family encode for the same amino acid sequence. CaM, a ubiquitous cytoplasmic calcium ion receptor, regulates the function of a variety of target molecules even in a single cell. Maintenance of the fidelity of the active CaM-target interactions in different compartments of the cell requires a rather complex control of the total cellular CaM pool comprising multiple levels of regulatory circuits. Among these mechanisms, it has long been proposed that a multigene family maximizes the regulatory potentials at the level of the gene expression. CaM genes are expressed at a particularly profound level in the mammalian central nervous system (CNS), especially in the highly polarized neurons. Thus, in the search for clear evidence of the suggested differential expression of the CaM genes, much of the research has been focused on the elements of the CNS. This review aims to give a comprehensive survey on the current understanding of this field at the level of the regulation of CaM mRNA transcription and distribution in the rodent brain. The results indicate that the CaM genes are indeed expressed in a gene-specific manner in the developing and adult brain under physiological conditions. To establish local CaM pools in distant intracellular compartments (dendrites and glial processes), local protein synthesis from differentially targeted mRNAs is also employed. Moreover, the CaM genes are controlled in a unique, gene-specific fashion when responding to certain external stimuli. Additionally, putative regulatory elements have been identified on the CaM genes and mRNAs.
Collapse
Affiliation(s)
- Arpad Palfi
- Department of Zoology and Cell Biology, University of Szeged, Hungary
| | | | | | | | | | | |
Collapse
|
28
|
Stebbings H. Cytoskeleton-dependent transport and localization of mRNA. INTERNATIONAL REVIEW OF CYTOLOGY 2002; 211:1-31. [PMID: 11597002 DOI: 10.1016/s0074-7696(01)11016-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Messenger RNAs are localized in both somatic and germ cells as a means of focusing the translation of proteins at specific cellular sites. The signals for this lie within the mRNA, and these are recognized by proteins in the cell. The latter appear to be attached via linker proteins to the transport machinery for localization. In some instances it is a myosin motor which translocates along actin microfilaments, and in others kinesin or dynein motors appear to be responsible for driving the movement of mRNA along microtubule substrates. The way that cytoskeleton-based mRNA translocation is regulated is speculated upon.
Collapse
Affiliation(s)
- H Stebbings
- School of Biological Sciences, Washington Singer Laboratories, University of Exeter, United Kingdom
| |
Collapse
|
29
|
Jasmin BJ, Angus LM, Bélanger G, Chakkalakal JV, Gramolini AO, Lunde JA, Stocksley MA, Thompson J. Multiple regulatory events controlling the expression and localization of utrophin in skeletal muscle fibers: insights into a therapeutic strategy for Duchenne muscular dystrophy. JOURNAL OF PHYSIOLOGY, PARIS 2002; 96:31-42. [PMID: 11755781 DOI: 10.1016/s0928-4257(01)00078-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Duchenne muscular dystrophy (DMD) is the most prevalent inherited muscle disease and results from mutations/deletions in the X-linked dystrophin gene. Although several approaches have been envisaged to counteract the effects of this progressive disease, there is currently no cure available. One strategy consists in utilizing a protein normally expressed in DMD muscle which, once expressed at appropriate levels and at the correct subcellular location, could compensate for the lack of dystrophin. A candidate for such a role is the dystrophin-related protein now referred to as utrophin. In contrast to dystrophin, which is expressed along the length of healthy muscle fibers, utrophin accumulates at the neuromuscular junction in both normal and DMD fibers. Several years ago, we began a series of experiments to determine the mechanisms responsible for the expression of utrophin at the neuromuscular synapse. Initially, we showed that utrophin transcripts accumulate preferentially within the postsynaptic sarcoplasm. To determine whether selective transcription of the utrophin gene accounts for this synaptic accumulation of utrophin mRNAs, we injected several utrophin promoter-reporter constructs directly into mouse muscle and demonstrated the preferential synaptic expression of the reporter gene. These results suggested that local transcriptional activation of the utrophin gene is responsible for the accumulation of utrophin mRNAs at the neuromuscular junction. In these studies, we also demonstrated that an N-box motif contained within the utrophin promoter plays a critical role in directing the synapse-specific expression of the utrophin gene. Additionally, our studies have shown that the ets-factors GABP alpha and beta are part of a protein complex that can bind to the N-box motif to transactivate the gene in muscle cells in culture and in vivo. In these experiments, we also noted that the nerve-derived trophic factors agrin and ARIA/heregulin regulate expression of utrophin via the activation of GABP alpha and beta which in turn, transactivate the utrophin gene via the N-box motif. Although these studies demonstrate that transcriptional activation can regulate utrophin mRNA levels, it is possible that additional mechanisms are also involved. In particular, the association of mRNAs with cytoskeletal elements and RNA-binding proteins may contribute to the accumulation of utrophin transcripts within the postsynaptic sarcoplasm. In recent studies, we have begun to examine this and we have now identified specific regions within the 3' untranslated region that are necessary for targeting and stabilizing utrophin mRNAs in skeletal muscle cells. A series of in vivo studies have also led us to conclude that post-transcriptional mechanisms are indeed important in regulating the abundance of utrophin transcripts in muscle. Together, these studies should lead to the identification of cis- and trans-acting elements regulating transcription of the utrophin gene as well as the stability and targeting of its mRNA in muscle cells. The results should therefore, identify specific targets that may become important in designing specific pharmacological interventions directed at increasing the expression of utrophin into extrasynaptic regions of DMD muscle fibers. In addition, these findings will contribute to our basic understanding of the cellular and molecular events involved in the formation, maintenance and plasticity of the neuromuscular synapse.
Collapse
Affiliation(s)
- Bernard J Jasmin
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, and Ottawa Health Research Institute, Ottawa, Ontario, Canada K1H 8M5.
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Raghavan A, Robison RL, McNabb J, Miller CR, Williams DA, Bohjanen PR. HuA and tristetraprolin are induced following T cell activation and display distinct but overlapping RNA binding specificities. J Biol Chem 2001; 276:47958-65. [PMID: 11602610 DOI: 10.1074/jbc.m109511200] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AU-rich elements found in the 3'-untranslated regions of cytokine and proto-oncogene transcripts regulate mRNA degradation and function as binding sites for the mRNA-stabilizing protein HuA and the mRNA-destabilizing protein tristetraprolin. Experiments were performed to evaluate the expression of HuA and tristetraprolin in purified human T lymphocytes and to evaluate the ability of these proteins to recognize specific AU-rich sequences. HuA is a predominantly nuclear protein that can also be found in the cytoplasm of resting T lymphocytes. Within 1 h after stimulation of T lymphocytes with anti-T cell receptor antibodies or a combination of a phorbol myristate acetate and ionomycin, an increase in cytoplasmic HuA RNA-binding activity was observed. Although absent in resting cells, cytoplasmic tristetraprolin protein was detected 3-6 h following activation. HuA recognized specific AU-rich sequences found in c-jun or c-myc mRNA that were poorly recognized by tristetraprolin. In contrast, tristetraprolin recognized an AU-rich sequence in interleukin-2 mRNA that was poorly recognized by HuA. Both HuA and tristetraprolin, however, recognized AU-rich sequences from c-fos, interleukin-3, tumor necrosis factor-alpha, and granulocyte/macrophage colony-stimulating factor mRNA. HuA may transiently stabilize a subset of AU-rich element-containing transcripts following T lymphocyte activation, and tristetraprolin may subsequently mediate their degradation.
Collapse
Affiliation(s)
- A Raghavan
- Department of Microbiology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | | | | | | | | | | |
Collapse
|
31
|
Gramolini AO, Bélanger G, Jasmin BJ. Distinct regions in the 3' untranslated region are responsible for targeting and stabilizing utrophin transcripts in skeletal muscle cells. J Cell Biol 2001; 154:1173-83. [PMID: 11551978 PMCID: PMC2150820 DOI: 10.1083/jcb.200101108] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, we have sought to determine whether utrophin transcripts are targeted to a distinct subcellular compartment in skeletal muscle cells, and have examined the role of the 3' untranslated region (UTR) in regulating the stability and localization of utrophin transcripts. Our results show that utrophin transcripts associate preferentially with cytoskeleton-bound polysomes via actin microfilaments. Because this association is not evident in myoblasts, our findings also indicate that the localization of utrophin transcripts with cytoskeleton-bound polysomes is under developmental influences. Transfection of LacZ reporter constructs containing the utrophin 3'UTR showed that this region is critical for targeting chimeric mRNAs to cytoskeleton-bound polysomes and controlling transcript stability. Deletion studies resulted in the identification of distinct regions within the 3'UTR responsible for targeting and stabilizing utrophin mRNAs. Together, these results illustrate the contribution of posttranscriptional events in the regulation of utrophin in skeletal muscle. Accordingly, these findings provide novel targets, in addition to transcriptional events, for which pharmacological interventions may be envisaged to ultimately increase the endogenous levels of utrophin in skeletal muscle fibers from Duchenne muscular dystrophy (DMD) patients.
Collapse
Affiliation(s)
- A O Gramolini
- Department of Cellular and Molecular Medicine, Faculty of Medicine, and Center for Neuromuscular Disease, University of Ottawa, Canada
| | | | | |
Collapse
|
32
|
Bermano G, Shepherd RK, Zehner ZE, Hesketh JE. Perinuclear mRNA localisation by vimentin 3'-untranslated region requires a 100 nucleotide sequence and intermediate filaments. FEBS Lett 2001; 497:77-81. [PMID: 11377416 DOI: 10.1016/s0014-5793(01)02438-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The role of the vimentin 3'-untranslated region (3'-UTR) in mRNA localisation was studied in cells transfected with a reporter sequence linked to subregions of the 3'-UTR. In situ hybridisation showed that nucleotides 37-137, including a previously identified protein-binding domain, were sufficient to localise transcripts to perinuclear cytoplasm. Transfection of two SW13 cell lines that do and do not express vimentin showed that perinuclear localisation due to either the vimentin or c-myc 3'-UTR requires intermediate filaments. The data suggest that both a specific protein-binding region of the vimentin 3'-UTR and intermediate filaments themselves are required to determine the site of vimentin synthesis.
Collapse
Affiliation(s)
- G Bermano
- Intrecellular Targeting Group, Rowett Research Institute Aberdeen, UK
| | | | | | | |
Collapse
|
33
|
Dalgleish G, Veyrune JL, Blanchard JM, Hesketh J. mRNA localization by a 145-nucleotide region of the c-fos 3'--untranslated region. Links to translation but not stability. J Biol Chem 2001; 276:13593-9. [PMID: 11139568 DOI: 10.1074/jbc.m001141200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The presence of a localization signal in the 3'-untranslated region of c-fos mRNA was investigated by in situ hybridization and cell fractionation techniques. Cells were transfected with chimeric gene constructs in which the beta-globin coding region was used as a reporter and linked to either its own 3'-untranslated region, the c-fos 3'-untranslated region, or the c-fos 3'-untranslated region containing different deletions. Replacement of the endogenous beta-globin 3'-untranslated region by that from c-fos caused a redistribution of the transcripts so that they were recovered in cytoskeletal-bound polysomes and seen localized in the perinuclear cytoplasm. Deletion of the AU-rich instability region did not affect transcript localization, but removal of a distinct 145-nucleotide region of the 3'-untranslated region abolished it. The prevention of transcript translation by desferrioxamine led to a marked loss of transcript localization, independent of mRNA instability. The data show that the 3'-untranslated region of c-fos mRNA, as c-myc, contains a localization signal, which targets the mRNA to the perinuclear cytoskeleton. We propose that this is important to ensure efficient nuclear import of these key regulatory proteins. mRNA localization by the fos 3'-untranslated region is independent of mRNA instability, and the two are determined by different regulatory elements.
Collapse
Affiliation(s)
- G Dalgleish
- Rowett Research Institute, Bucksburn, Aberdeen, AB21 9SB Scotland, United Kingdom
| | | | | | | |
Collapse
|
34
|
Brennan CM, Gallouzi IE, Steitz JA. Protein ligands to HuR modulate its interaction with target mRNAs in vivo. J Cell Biol 2000; 151:1-14. [PMID: 11018049 PMCID: PMC2189805 DOI: 10.1083/jcb.151.1.1] [Citation(s) in RCA: 302] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2000] [Accepted: 08/15/2000] [Indexed: 02/08/2023] Open
Abstract
AU-rich elements (AREs) present in the 3' untranslated regions of many protooncogene, cytokine, and lymphokine messages target them for rapid degradation. HuR, a ubiquitously expressed member of the ELAV (embryonic lethal abnormal vision) family of RNA binding proteins, selectively binds AREs and stabilizes ARE-containing mRNAs in transiently transfected cells. Here, we identify four mammalian proteins that bind regions of HuR known to be essential for its ability to shuttle between the nucleus and the cytoplasm and to stabilize mRNA: SETalpha, SETbeta, pp32, and acidic protein rich in leucine (APRIL). Three have been reported to be protein phosphatase 2A inhibitors. All four ligands contain long, acidic COOH-terminal tails, while pp32 and APRIL share a second motif: rev-like leucine-rich repeats in their NH(2)-terminal regions. We show that pp32 and APRIL are nucleocytoplasmic shuttling proteins that interact with the nuclear export factor CRM1 (chromosomal region maintenance protein 1). The inhibition of CRM1 by leptomycin B leads to the nuclear retention of pp32 and APRIL, their increased association with HuR, and an increase in HuR's association with nuclear poly(A)+ RNA. Furthermore, transcripts from the ARE-containing c-fos gene are selectively retained in the nucleus, while the cytoplasmic distribution of total poly(A)+ RNA is not altered. These data provide evidence that interaction of its ligands with HuR modulate HuR's ability to bind its target mRNAs in vivo and suggest that CRM1 is instrumental in the export of at least some cellular mRNAs under certain conditions. We discuss the possible role of these ligands upstream of HuR in pathways that govern the stability of ARE-containing mRNAs.
Collapse
Affiliation(s)
- C M Brennan
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06536, USA
| | | | | |
Collapse
|
35
|
Koishi K, Dalzell KG, McLennan IS. The expression and structure of TGF-beta2 transcripts in rat muscles. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1492:311-9. [PMID: 10899565 DOI: 10.1016/s0304-419x(00)00012-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The transforming growth factor-beta2 (TGF-beta2) transcripts expressed in various tissues of rat were characterised by RT-PCR and the nucleotide sequence of the cDNAs determined. A transcript with an 84-nucleotide insert in the latency-associated peptide region, the long form, was found. The long form of TGF-beta2 was detected in the aorta, primary bronchus, uterus, heart, skeletal muscle, sciatic nerve and spinal cord but not in the intestine. The 3' untranslated region of TGF-beta2 contained several putative AU-rich elements and multiple polyadenylation sites, indicating post-transcriptional regulation of TGF-beta2 synthesis. The levels of TGF-beta2 transcripts were estimated using semi-quantitative RT-PCR. They were down-regulated during muscle development and up-regulated after denervation. The long form constituted approximately 6% of the total TGF-beta2 messages in skeletal muscle.
Collapse
Affiliation(s)
- K Koishi
- Department of Anatomy and Structural Biology, School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
| | | | | |
Collapse
|
36
|
Levadoux M, Mahon C, Beattie JH, Wallace HM, Hesketh JE. Nuclear import of metallothionein requires its mRNA to be associated with the perinuclear cytoskeleton. J Biol Chem 1999; 274:34961-6. [PMID: 10574972 DOI: 10.1074/jbc.274.49.34961] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The influence of mRNA localization on metallothionein-1 protein distribution was studied by immunocytochemistry. We used Chinese hamster ovary cells that had been transfected with either a native metallothionein-1 gene construct or metallothionein-1 5'-untranslated region and coding sequences linked to the 3'-untranslated region from glutathione peroxidase. The change in the 3'-untranslated region caused the delocalization of the mRNA with a loss of the perinuclear localization and association with the cytoskeleton. Clones were selected which expressed similar levels of metallothionein-1 protein, as assessed by radioimmunoassay. The results showed that loss of metallothionein-1 mRNA localization was associated with a loss of metallothionein-1 protein localization, most notably with a lack of metallothionein-1 protein in the nucleus of synchronized cells which were beginning to synthesize DNA. This indicates that the association of metallothionein-1 mRNA with the cytoskeleton around the nucleus is essential for efficient shuttling of the protein into the nucleus during the G(1) to S phase transition. This is the first demonstration of a physiological role for perinuclear mRNA localization and we propose that such localization may be important for a wide range of nuclear proteins, including those that shuttle between nucleus and cytoplasm in a cell cycle dependent manner.
Collapse
Affiliation(s)
- M Levadoux
- Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, United Kingdom
| | | | | | | | | |
Collapse
|
37
|
Dalgleish GD, Veyrune JL, Accornero N, Blanchard JM, Hesketh JE. Localisation of a reporter transcript by the c-myc 3'-UTR is linked to translation. Nucleic Acids Res 1999; 27:4363-8. [PMID: 10536143 PMCID: PMC148717 DOI: 10.1093/nar/27.22.4363] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The 3'-untranslated region of c-myc mRNA contains a perinuclear localisation signal which is sufficient to target beta-globin coding sequences. The link between perinuclear mRNA localisation and translation has been investigated using cells transfected with chimeric gene constructs in which globin reporter sequences were linked to the c-myc 3'-untranslated region and the iron-responsive element from ferritin mRNA. Iron supplementation of the medium promoted translation of the chimeric mRNA as assessed by its presence in polysomes; in situ hybridisation showed that the mRNA was localised around the nucleus. Treatment with the iron chelator desferrioxamine for 16 h prevented both translation and mRNA localisation. In controls where the expressed mRNA lacked the iron-responsive element desferrioxamine had no effect upon localisation. In contrast, arrest of on-going global translation by puromycin treatment had no effect on mRNA localisation. The data suggest that if initiation of translation of a mRNA containing the c-myc localisation signal is prevented in some way then localisation does not occur, whereas once the mRNA has been localised further translation is not required to maintain mRNA localisation.
Collapse
Affiliation(s)
- G D Dalgleish
- Intracellular Targeting Group, Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK
| | | | | | | | | |
Collapse
|
38
|
Mittaz L, Rossier C, Heino M, Peterson P, Krohn KJ, Gos A, Morris MA, Kudoh J, Shimizu N, Antonarakis SE, Scott HS. Isolation and characterization of the mouse Aire gene. Biochem Biophys Res Commun 1999; 255:483-90. [PMID: 10049735 DOI: 10.1006/bbrc.1999.0223] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disorder characterized by Addison's disease and/or hypoparathyroidism and/or chronic mucocutaneous candidiasis. Patients may also have other clinical symptoms both within and outside the endocrine system, mainly as a result of autoimmunity against organ-specific autoantigens. The gene for APECED has recently been identified and termed AIRE (for AutoImmune REgulator). APECED is a model of organ-specific autoimmunity and isolation and characterization of the homologous mouse gene, Aire, will provide tools for dissection of the mechanisms underlying this human disorder and defining molecular pathways involved in organ-specific autoimmunity. We have isolated and completely sequenced the mouse Aire gene which is split into 14 exons over 13 kb and encodes a predicted protein of 552 amino acids. The predicted mouse and human AIRE proteins are 71% identical and contain motifs suggestive of a transcriptional regulator. Additional conserved motifs are emerging in the AIRE/Aire proteins including a nuclear localization signal, an "ASS" domain, and a "SAND" domain. The human and mouse AIRE promoters have conserved sites for several thymus-specific transcription factors and others important in hematopoesis, consistent with its expression in rare cells of the thymus medulla, lymph nodes, and fetal liver. We have mapped mouse Aire to mouse chromosome 10 by FISH, to the same region as Pwp2 and Pfkl, confirming synteny to the corresponding region of human chromosome 21.
Collapse
Affiliation(s)
- L Mittaz
- Division of Medical Genetics, University of Geneva, Medical School, Switzerland
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Martone ME, Pollock JA, Ellisman MH. Subcellular localization of mRNA in neuronal cells. Contributions of high-resolution in situ hybridization techniques. Mol Neurobiol 1998; 18:227-46. [PMID: 10206470 DOI: 10.1007/bf02741301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The development of technologies for high-resolution nucleic acid localization in cells and tissues has contributed significantly to our understanding of transcriptional and translational regulation in eukaryotic cells. These methods include nonisotopic in situ hybridization methods for light and electron microscopy, and fluorescent tagging for the study of nucleic acid behavior in living cells. In situ hybridization to detect messenger RNA has led to the discovery that individual transcripts may be selectively targeted to particular subcellular domains. In the nervous system, certain species of mRNA have been localized in distal processes in nerve cells and glia. Direct visualization of mRNA and its interactions with subcellular features, such as synaptic specializations, cytoskeletal elements, and nuclear pores, have been achieved. Of particular interest is the presence of mRNA and ribosomes in dendrites, beneath synaptic contacts, suggesting the possibility of synaptic regulation of protein synthesis. The following article will describe the application of high-resolution in situ hybridization and live imaging techniques to the study of mRNA targeting in neurons.
Collapse
Affiliation(s)
- M E Martone
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California, San Diego, La Jolla 92093-0608, USA
| | | | | |
Collapse
|
40
|
Voeltz GK, Steitz JA. AUUUA sequences direct mRNA deadenylation uncoupled from decay during Xenopus early development. Mol Cell Biol 1998; 18:7537-45. [PMID: 9819439 PMCID: PMC109334 DOI: 10.1128/mcb.18.12.7537] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/1998] [Accepted: 08/23/1998] [Indexed: 11/20/2022] Open
Abstract
To study the regulation of AUUUA-mediated RNA deadenylation and destabilization during Xenopus early development, we microinjected chimeric mRNAs containing Xenopus or mammalian 3' untranslated region (3'-UTR) sequences into Xenopus oocytes, mature eggs, or fertilized embryos. We found that the AU-rich elements (ARE) of Xenopus c-myc II and the human granulocyte-macrophage colony-stimulating factor gene (GMCSF) both direct deadenylation of chimeric mRNAs in an AUUUA-dependent manner. In the case of the Xenopus c-myc II ARE, mutation of a single AUUUA within an absolutely conserved 11-nucleotide region in c-myc 3'-UTRs prevents ARE-mediated deadenylation. AUUUA-specific deadenylation appears to be developmentally regulated: low deadenylation activity is observed in the oocyte, whereas rapid deadenylation occurs following egg activation or fertilization. Deadenylation results in the accumulation of stable deadenylated RNAs that become degraded only following mid-blastula transition. We conclude that ARE-mediated mRNA deadenylation can be uncoupled from ARE-mediated mRNA decay and that AUUUAs directly signal deadenylation during Xenopus early development.
Collapse
Affiliation(s)
- G K Voeltz
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06536, USA
| | | |
Collapse
|
41
|
Regulatory signals in messenger RNA: determinants of nutrient–gene interaction and metabolic compartmentation. Br J Nutr 1998. [DOI: 10.1017/s0007114598001378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Nutrition has marked influences on gene expression and an understanding of the interaction between nutrients and gene expression is important in order to provide a basis for determining the nutritional requirements on an individual basis. The effects of nutrition can be exerted at many stages between transcription of the genetic sequence and production of a functional protein. This review focuses on the role of post-transcriptional control, particularly mRNA stability, translation and localization, in the interactions of nutrients with gene expression. The effects of both macronutrients and micronutrients on regulation of gene expression by post-transcriptional mechanisms are presented and the post-transcriptional regulation of specific genes of nutritional relevance (glucose transporters, transferrin, selenoenzymes, metallothionein, lipoproteins) is described in detail. The function of the regulatory signals in the untranslated regions of the mRNA is highlighted in relation to control of mRNA stability, translation and localization and the importance of these mRNA regions to regulation by nutrients is illustrated by reference to specific examples. The localization of mRNA by signals in the untranslated regions and its function in the spatial organization of protein synthesis is described; the potential of such mechanisms to play a key part in nutrient channelling and metabolic compartmentation is discussed. It is concluded that nutrients can influence gene expression through control of the regulatory signals in these untranslated regions and that the post-transcriptional regulation of gene expression by these mechanisms may influence nutritional requirements. It is emphasized that in studies of nutritional control of gene expression it is important not to focus only on regulation through gene promoters but also to consider the possibility of post-transcriptional control.
Collapse
|
42
|
Frenette J, Tidball JG. Mechanical loading regulates expression of talin and its mRNA, which are concentrated at myotendinous junctions. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:C818-25. [PMID: 9730966 DOI: 10.1152/ajpcell.1998.275.3.c818] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The hypothesis that mechanical loading regulates talin expression in developing and adult muscle was tested using in vitro and in vivo models. Talin was selected for study because it is a key structural link between the cytoskeleton and cell membrane. In the in vitro model, C2C12 myotubes were subjected to cyclic strains for 48 h. In the in vivo model, rat hindlimb muscles were unloaded for 10 days, then reloaded for 2 days. Cyclic loading of myotubes resulted in significant increases in the quantity of talin (68%) and its 190-kDa proteolytic fragment (70%), as well as talin mRNA (180%), relative to unloaded myotube cultures. Similarly, talin concentration and its mRNA increased by 68 and 136%, respectively, in soleus muscles reloaded for 2 days relative to ambulatory controls. Immunohistochemistry and in situ RT-PCR showed that talin and its mRNA are concentrated and colocalized at myotendinous junctions. Thus these findings indicate that increased mechanical loading promotes talin synthesis, which occurs principally at myotendinous junctions, according to talin mRNA distribution.
Collapse
Affiliation(s)
- J Frenette
- Department of Physiological Science, University of California, Los Angeles, California 90095-1524, USA
| | | |
Collapse
|
43
|
Gallouzi IE, Parker F, Chebli K, Maurier F, Labourier E, Barlat I, Capony JP, Tocque B, Tazi J. A novel phosphorylation-dependent RNase activity of GAP-SH3 binding protein: a potential link between signal transduction and RNA stability. Mol Cell Biol 1998; 18:3956-65. [PMID: 9632780 PMCID: PMC108980 DOI: 10.1128/mcb.18.7.3956] [Citation(s) in RCA: 169] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A potential p120 GTPase-activating protein (RasGAP) effector, G3BP (RasGAP Src homology 3 [SH3] binding protein), was previously identified based on its ability to bind the SH3 domain of RasGAP. Here we show that G3BP colocalizes and physically interacts with RasGAP at the plasma membrane of serum-stimulated but not quiescent Chinese hamster lung fibroblasts. In quiescent cells, G3BP was hyperphosphorylated on serine residues, and this modification was essential for its activity. Indeed, G3BP harbors a phosphorylation-dependent RNase activity which specifically cleaves the 3'-untranslated region of human c-myc mRNA. The endoribonuclease activity of G3BP can initiate mRNA degradation and therefore represents a link between a RasGAP-mediated signaling pathway and RNA turnover.
Collapse
Affiliation(s)
- I E Gallouzi
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, Université Montpellier II, F34293 Montpellier Cedex 5, France
| | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Schuurs TA, Dalstra HJ, Scheer JM, Wessels JG. Positioning of nuclei in the secondary Mycelium of Schizophyllum commune in relation to differential gene expression. Fungal Genet Biol 1998; 23:150-61. [PMID: 9578628 DOI: 10.1006/fgbi.1997.1028] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this paper we propose a novel type of gene regulation in the MATA|l4 MATB|l4 heterokaryon of Schizophyllum commune by means of differential positioning of the nuclei. It was found that binucleate hyphae with juxtaposed nuclei secrete SC4 hydrophobin (abundant during fruit-body formation), while SC3 (abundant during aerial hyphae formation in both mono- and dikaryons) appeared to be absent. Certain growth conditions disrupted the binucleate state in that the compatible nuclei became separated at a considerable distance. Under these conditions SC4 was not secreted while SC3 was secreted to a high degree. Disruption of the binucleate state was earlier observed in developing aerial hyphae which secrete SC3. Apparently, when the nuclei are in close proximity the dikaryon-expressed genes are switched on by interaction of the products of the MATA and MATB mating-type genes, while SC3 is suppressed by interacting products of the MATB genes, as occurs in the common MATA heterokaryon (MATA= MATB|l4). Growth conditions that lead to disruption of the binucleate state apparently result in abolishment of interaction between the MATB mating-type genes. Under these conditions, dikaryon-specific mRNAs do not accumulate in the MATA|l4 MATB|l4 heterokaryon, while SC3 mRNA becomes highly abundant.
Collapse
Affiliation(s)
- T A Schuurs
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, Haren, 9751 NN, The Netherlands
| | | | | | | |
Collapse
|
45
|
Mahon P, Partridge K, Beattie JH, Glover LA, Hesketh JE. The 3' untranslated region plays a role in the targeting of metallothionein-I mRNA to the perinuclear cytoplasm and cytoskeletal-bound polysomes. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1358:153-62. [PMID: 9332451 DOI: 10.1016/s0167-4889(97)00058-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The mechanism of localisation of metallothionein-I (MT-I) mRNA was studied in transfected cells by in situ hybridisation and cell fractionation. Hepatoma cells were transfected with the 5'-untranslated region and coding region of the beta-globin gene alone or linked to either the beta-globin 3'-untranslated region (3'-UTR) or the MT-I 3'-UTR. The wild-type beta-globin mRNA and the beta-globin mRNA lacking its native 3'-UTR were present in free and cytoskeletal-bound polysomes to a similar extent and showed no localisation. Chimaeric globin-metallothionein transcripts were significantly enriched in cytoskeletal-bound polysomes and were localised in the perinuclear cytoplasm. Chimaeric globin-metallothionein and wild-type globin transcripts were of similar stability. Chinese Hamster Ovary cells were transfected with constructs in which the MT-I 5'-untranslated region and coding sequences were linked to either the endogenous 3'-UTR or the glutathione peroxidase 3'-UTR. Wild-type MT-I transcripts were localised in the perinuclear cytoplasm but the chimaeric MT-I-glutathione peroxidase transcripts showed no distinct localisation. The results indicate that the 3'-UTR of MT-I mRNA contains a localisation signal which promotes both the association of the mRNA with the cytoskeleton and its perinuclear localisation.
Collapse
Affiliation(s)
- P Mahon
- Intracellular Targeting Group, Rowett Research Institute, Bucksburn, Aberdeen, UK
| | | | | | | | | |
Collapse
|
46
|
Wiseman JW, Glover LA, Hesketh JE. Evidence for a localisation signal in the 3'-untranslated region from vimentin messenger RNA. Int J Biochem Cell Biol 1997; 29:1013-20. [PMID: 9375381 DOI: 10.1016/s1357-2725(97)00034-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
There is increasing evidence that some mRNAs are localised in eukaryotic somatic cells, but it is unclear what proportion of mRNAs are localised and whether this sorting involves 3'-untranslated sequences. The presence of a localisation signal within the 3'-untranslated region of vimentin mRNA was investigated by studying mRNA distribution in fibroblasts transfected with beta-globin and hybrid globin-vimentin gene constructs. In cells transfected with constructs containing either a fragment of the rabbit beta-globin gene containing both coding sequences and 3'untranslated region or the beta-globin coding sequences alone in situ hybridisation showed that beta-globin mRNA was distributed throughout the cytoplasm without any evident localisation. In contrast, in cells transfected with globin coding sequences linked to the vimentin 3'-untranslated region there was a strong perinuclear localisation of the hybrid mRNA. The results show that loss of its endogenous 3'-untranslated region does not affect distribution of beta-globin mRNA whereas the vimentin 3'-untranslated region causes an altered localisation of beta-globin mRNA. We conclude that the vimentin 3'-untranslated region contains a localisation signal which can direct reporter sequences to the perinuclear cytoplasm.
Collapse
Affiliation(s)
- J W Wiseman
- Department of Molecular and Cell Biology, Institute of Medical Sciences, Foresterhill, Aberdeen, U.K
| | | | | |
Collapse
|
47
|
Veyrune JL, Hesketh J, Blanchard JM. 3' untranslated regions of c-myc and c-fos mRNAs: multifunctional elements regulating mRNA translation, degradation and subcellular localization. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 1997; 18:35-63. [PMID: 8994260 DOI: 10.1007/978-3-642-60471-3_3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- J L Veyrune
- Institut de Génétique Moléculaire de Montpellier, CNRS, UMR 5535, Montpellier, France
| | | | | |
Collapse
|