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Varesi A, Campagnoli LIM, Barbieri A, Rossi L, Ricevuti G, Esposito C, Chirumbolo S, Marchesi N, Pascale A. RNA binding proteins in senescence: A potential common linker for age-related diseases? Ageing Res Rev 2023; 88:101958. [PMID: 37211318 DOI: 10.1016/j.arr.2023.101958] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/09/2023] [Accepted: 05/18/2023] [Indexed: 05/23/2023]
Abstract
Aging represents the major risk factor for the onset and/or progression of various disorders including neurodegenerative diseases, metabolic disorders, and bone-related defects. As the average age of the population is predicted to exponentially increase in the coming years, understanding the molecular mechanisms underlying the development of aging-related diseases and the discovery of new therapeutic approaches remain pivotal. Well-reported hallmarks of aging are cellular senescence, genome instability, autophagy impairment, mitochondria dysfunction, dysbiosis, telomere attrition, metabolic dysregulation, epigenetic alterations, low-grade chronic inflammation, stem cell exhaustion, altered cell-to-cell communication and impaired proteostasis. With few exceptions, however, many of the molecular players implicated within these processes as well as their role in disease development remain largely unknown. RNA binding proteins (RBPs) are known to regulate gene expression by dictating at post-transcriptional level the fate of nascent transcripts. Their activity ranges from directing primary mRNA maturation and trafficking to modulation of transcript stability and/or translation. Accumulating evidence has shown that RBPs are emerging as key regulators of aging and aging-related diseases, with the potential to become new diagnostic and therapeutic tools to prevent or delay aging processes. In this review, we summarize the role of RBPs in promoting cellular senescence and we highlight their dysregulation in the pathogenesis and progression of the main aging-related diseases, with the aim of encouraging further investigations that will help to better disclose this novel and captivating molecular scenario.
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Affiliation(s)
- Angelica Varesi
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy.
| | | | - Annalisa Barbieri
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy
| | - Lorenzo Rossi
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | | | - Ciro Esposito
- Department of Internal Medicine and Therapeutics, University of Pavia, Italy; Nephrology and dialysis unit, ICS S. Maugeri SPA SB Hospital, Pavia, Italy; High School in Geriatrics, University of Pavia, Italy
| | | | - Nicoletta Marchesi
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy
| | - Alessia Pascale
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy.
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2
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Souidi A, Nakamori M, Zmojdzian M, Jagla T, Renaud Y, Jagla K. Deregulations of miR-1 and its target Multiplexin promote dilated cardiomyopathy associated with myotonic dystrophy type 1. EMBO Rep 2023; 24:e56616. [PMID: 36852954 PMCID: PMC10074075 DOI: 10.15252/embr.202256616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/03/2023] [Accepted: 02/14/2023] [Indexed: 03/01/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy in adults. It is caused by the excessive expansion of noncoding CTG repeats, which when transcribed affects the functions of RNA-binding factors with adverse effects on alternative splicing, processing, and stability of a large set of muscular and cardiac transcripts. Among these effects, inefficient processing and down-regulation of muscle- and heart-specific miRNA, miR-1, have been reported in DM1 patients, but the impact of reduced miR-1 on DM1 pathogenesis has been unknown. Here, we use Drosophila DM1 models to explore the role of miR-1 in cardiac dysfunction in DM1. We show that miR-1 down-regulation in the heart leads to dilated cardiomyopathy (DCM), a DM1-associated phenotype. We combined in silico screening for miR-1 targets with transcriptional profiling of DM1 cardiac cells to identify miR-1 target genes with potential roles in DCM. We identify Multiplexin (Mp) as a new cardiac miR-1 target involved in DM1. Mp encodes a collagen protein involved in cardiac tube formation in Drosophila. Mp and its human ortholog Col15A1 are both highly enriched in cardiac cells of DCM-developing DM1 flies and in heart samples from DM1 patients with DCM, respectively. When overexpressed in the heart, Mp induces DCM, whereas its attenuation rescues the DCM phenotype of aged DM1 flies. Reduced levels of miR-1 and consecutive up-regulation of its target Mp/Col15A1 might be critical in DM1-associated DCM.
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Affiliation(s)
- Anissa Souidi
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
| | - Masayuki Nakamori
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Monika Zmojdzian
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
| | - Teresa Jagla
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
| | - Yoan Renaud
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
| | - Krzysztof Jagla
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
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3
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Busa VF, Favorov AV, Fertig EJ, Leung AK. Spatial correlation statistics enable transcriptome-wide characterization of RNA structure binding. CELL REPORTS METHODS 2021; 1:100088. [PMID: 35474897 PMCID: PMC9017189 DOI: 10.1016/j.crmeth.2021.100088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 06/23/2021] [Accepted: 08/30/2021] [Indexed: 11/20/2022]
Abstract
Molecular interactions at identical transcriptomic locations or at proximal but non-overlapping sites can mediate RNA modification and regulation, necessitating tools to uncover these spatial relationships. We present nearBynding, a flexible algorithm and software pipeline that models spatial correlation between transcriptome-wide tracks from diverse data types. nearBynding can process and correlate interval as well as continuous data and incorporate experimentally derived or in silico predicted transcriptomic tracks. nearBynding offers visualization functions for its statistics to identify colocalizations and adjacent features. We demonstrate the application of nearBynding to correlate RNA-binding protein (RBP) binding preferences with other RBPs, RNA structure, or RNA modification. By cross-correlating RBP binding and RNA structure data, we demonstrate that nearBynding recapitulates known RBP binding to structural motifs and provides biological insights into RBP binding preference of G-quadruplexes. nearBynding is available as an R/Bioconductor package and can run on a personal computer, making correlation of transcriptomic features broadly accessible.
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Affiliation(s)
- Veronica F. Busa
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Alexander V. Favorov
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Laboratory of Systems Biology and Computational Genetics, Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Elana J. Fertig
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Biomedical Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, MD 21205, USA
- Department of Applied Mathematics and Statistics, Johns Hopkins University Whiting School of Engineering, Baltimore, MD 21205, USA
| | - Anthony K.L. Leung
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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4
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Cox DC, Guan X, Xia Z, Cooper TA. Increased nuclear but not cytoplasmic activities of CELF1 protein leads to muscle wasting. Hum Mol Genet 2020; 29:1729-1744. [PMID: 32412585 PMCID: PMC7322576 DOI: 10.1093/hmg/ddaa095] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/16/2020] [Accepted: 05/12/2020] [Indexed: 12/19/2022] Open
Abstract
mRNA processing is highly regulated during development through changes in RNA-binding protein (RBP) activities. CUG-BP, Elav-like family member 1 (CELF1, also called CUGBP1) is an RBP, the expression of which decreases in skeletal muscle soon after birth. CELF1 regulates multiple nuclear and cytoplasmic RNA processing events. In the nucleus, CELF1 regulates networks of postnatal alternative splicing (AS) transitions, while in the cytoplasm, CELF1 regulates mRNA stability and translation. Stabilization and misregulation of CELF1 has been implicated in human diseases including myotonic dystrophy type 1, Alzheimer's disease and multiple cancers. To understand the contribution of nuclear and cytoplasmic CELF1 activity to normal and pathogenic skeletal muscle biology, we generated transgenic mice for doxycycline-inducible and skeletal muscle-specific expression of active CELF1 mutants engineered to be localized predominantly to either the nucleus or the cytoplasm. Adult mice expressing nuclear, but not cytoplasmic, CELF1 are characterized by strong histopathological defects, muscle loss within 10 days and changes in AS. In contrast, mice expressing cytoplasmic CELF1 display changes in protein levels of targets known to be regulated at the level of translation by CELF1, with minimal changes in AS. These changes are in the absence of overt histopathological changes or muscle loss. RNA-sequencing revealed extensive gene expression and AS changes in mice overexpressing nuclear and naturally localized CELF1 protein, with affected genes involved in cytoskeleton dynamics, membrane dynamics, RNA processing and zinc ion binding. These results support a stronger role for nuclear CELF1 functions as compared to cytoplasmic CELF1 functions in skeletal muscle wasting.
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Affiliation(s)
- Diana C Cox
- Department of Pathology & Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Department of Biochemistry & Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Xiangnan Guan
- Computational Biology Program, Oregon Health & Science University, Portland, OR 97239 USA
| | - Zheng Xia
- Computational Biology Program, Oregon Health & Science University, Portland, OR 97239 USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239 USA
| | - Thomas A Cooper
- Department of Pathology & Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston TX, 77030 USA
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5
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Abstract
Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are two of the most common liver diseases associated with obesity, type 2 diabetes and metabolic syndrome. The prevalence of these conditions are increasingly rising and presently there is not a pharmacological option available in the market. Elucidation of the mechanism of action and the molecular underpinnings behind liver disease could help to better understand the pathophysiology of these illnesses. In this sense, in the last years modulation of the ghrelin system in preclinical animal models emerge as a promising therapeutic tool. In this review, we compile the latest knowledge of the modulation of ghrelin system and its intracellular pathways that regulates lipid metabolism, hepatic inflammation and liver fibrosis. We also describe novel processes implicated in the regulation of liver disease by ghrelin, such as autophagy or dysregulated circadian rhythms. In conclusion, the information displayed in this review support that the ghrelin system could be an appealing strategy for the treatment of liver disease.
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Affiliation(s)
- Mar Quiñones
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Johan Fernø
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Omar Al-Massadi
- Inserm UMR-S1270, 75005, Paris, France.
- Faculté des Sciences et d'Ingénierie, Sorbonne Université, 75005, Paris, France.
- Institut du Fer a Moulin, Inserm, 17 rue du Fer à Moulin, 75005, Paris, France.
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6
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Emerging Role of C/EBPβ and Epigenetic DNA Methylation in Ageing. Trends Genet 2020; 36:71-80. [DOI: 10.1016/j.tig.2019.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/31/2019] [Accepted: 11/12/2019] [Indexed: 12/11/2022]
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7
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Timchenko L. Correction of RNA-Binding Protein CUGBP1 and GSK3β Signaling as Therapeutic Approach for Congenital and Adult Myotonic Dystrophy Type 1. Int J Mol Sci 2019; 21:ijms21010094. [PMID: 31877772 PMCID: PMC6982105 DOI: 10.3390/ijms21010094] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/13/2019] [Accepted: 12/17/2019] [Indexed: 01/02/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a complex genetic disease affecting many tissues. DM1 is caused by an expansion of CTG repeats in the 3′-UTR of the DMPK gene. The mechanistic studies of DM1 suggested that DMPK mRNA, containing expanded CUG repeats, is a major therapeutic target in DM1. Therefore, the removal of the toxic RNA became a primary focus of the therapeutic development in DM1 during the last decade. However, a cure for this devastating disease has not been found. Whereas the degradation of toxic RNA remains a preferential approach for the reduction of DM1 pathology, other approaches targeting early toxic events downstream of the mutant RNA could be also considered. In this review, we discuss the beneficial role of the restoring of the RNA-binding protein, CUGBP1/CELF1, in the correction of DM1 pathology. It has been recently found that the normalization of CUGBP1 activity with the inhibitors of GSK3 has a positive effect on the reduction of skeletal muscle and CNS pathologies in DM1 mouse models. Surprisingly, the inhibitor of GSK3, tideglusib also reduced the toxic CUG-containing RNA. Thus, the development of the therapeutics, based on the correction of the GSK3β-CUGBP1 pathway, is a promising option for this complex disease.
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Affiliation(s)
- Lubov Timchenko
- Departments of Neurology and Pediatrics, Cincinnati Children's Hospital Medical Center and the University of Cincinnati, Cincinnati, OH 45229, USA
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8
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Reddy K, Jenquin JR, Cleary JD, Berglund JA. Mitigating RNA Toxicity in Myotonic Dystrophy using Small Molecules. Int J Mol Sci 2019; 20:E4017. [PMID: 31426500 PMCID: PMC6720693 DOI: 10.3390/ijms20164017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/13/2019] [Accepted: 08/16/2019] [Indexed: 12/26/2022] Open
Abstract
This review, one in a series on myotonic dystrophy (DM), is focused on the development and potential use of small molecules as therapeutics for DM. The complex mechanisms and pathogenesis of DM are covered in the associated reviews. Here, we examine the various small molecule approaches taken to target the DNA, RNA, and proteins that contribute to disease onset and progression in myotonic dystrophy type 1 (DM1) and 2 (DM2).
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Affiliation(s)
- Kaalak Reddy
- The RNA Institute, University at Albany-SUNY, Albany, NY 12222, USA.
| | - Jana R Jenquin
- Center for NeuroGenetics and Biochemistry & Molecular Biology, University of Florida, Gainesville, FL 32608, USA
| | - John D Cleary
- The RNA Institute, University at Albany-SUNY, Albany, NY 12222, USA
| | - J Andrew Berglund
- The RNA Institute, University at Albany-SUNY, Albany, NY 12222, USA.
- Center for NeuroGenetics and Biochemistry & Molecular Biology, University of Florida, Gainesville, FL 32608, USA.
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9
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Yan JK, Zhang T, Dai LN, Gu BL, Zhu J, Yan WH, Cai W, Wang Y. CELF1/p53 axis: a sustained antiproliferative signal leading to villus atrophy under total parenteral nutrition. FASEB J 2018; 33:3378-3391. [PMID: 30514107 DOI: 10.1096/fj.201801695r] [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] [Indexed: 12/13/2022]
Abstract
Intestinal villus atrophy is a major complication of total parenteral nutrition (TPN). Our previous study revealed that TPN-induced villus atrophy is accompanied by elevated expression of CUGBP, Elav-like family member 1 (CELF1); however, its mechanism of action has not been fully understood. Herein, we report a pivotal role of CELF1/p53 axis, which induces a sustained antiproliferative signal, leading to suppressed proliferation of intestinal epithelial cells (IECs). By using a rat model of TPN, we found synchronous upregulation of CELF1 and p53 in jejunum mucosa, accompanied by a 51% decrease in crypt cell proliferation rate. By using HCT-116 cells as an IEC model in vitro, we found that the expression of CELF1 altered dynamically in parallel to proliferation rate, suggesting a self-adaptive expression pattern in IECs in vitro. Furthermore, ectopic overexpression of CELF1 elicited a significant antiproliferative effect in HCT-116, Caco-2, and IEC-6 cells, whereas knockdown of CELF1 elicited a significant proproliferative effect. Moreover, cell-cycle assay revealed that ectopic overexpression of CELF1 induced sustained G2 arrest and G1 arrest in HCT-116 and IEC-6 cells, respectively, which could be abolished by p53 silencing. Mechanistically, polysomal profiling and nascent protein analysis revealed that regulation of p53 by CELF1 was mediated through accelerating its protein translation in polysomes. Taken together, our findings revealed a sustained suppression of IEC proliferation evoked by CELF1/p53 axis, which may be a potential therapeutic target for the treatment of TPN-induced villus atrophy.-Yan, J.-K., Zhang, T., Dai, L.-N., Gu, B.-L., Zhu, J., Yan, W.-H., Cai, W., Wang, Y. CELF1/p53 axis: a sustained antiproliferative signal leading to villus atrophy under total parenteral nutrition.
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Affiliation(s)
- Jun-Kai Yan
- Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; and.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Tian Zhang
- Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; and
| | - Li-Na Dai
- Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; and
| | - Bei-Lin Gu
- Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; and.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Jie Zhu
- Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; and
| | - Wei-Hui Yan
- Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; and
| | - Wei Cai
- Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; and.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Ying Wang
- Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; and.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai Institute for Pediatric Research, Shanghai, China
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10
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Müller C, Zidek LM, Ackermann T, de Jong T, Liu P, Kliche V, Zaini MA, Kortman G, Harkema L, Verbeek DS, Tuckermann JP, von Maltzahn J, de Bruin A, Guryev V, Wang ZQ, Calkhoven CF. Reduced expression of C/EBPβ-LIP extends health and lifespan in mice. eLife 2018; 7:34985. [PMID: 29708496 PMCID: PMC5986274 DOI: 10.7554/elife.34985] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/27/2018] [Indexed: 02/06/2023] Open
Abstract
Ageing is associated with physical decline and the development of age-related diseases such as metabolic disorders and cancer. Few conditions are known that attenuate the adverse effects of ageing, including calorie restriction (CR) and reduced signalling through the mechanistic target of rapamycin complex 1 (mTORC1) pathway. Synthesis of the metabolic transcription factor C/EBPβ-LIP is stimulated by mTORC1, which critically depends on a short upstream open reading frame (uORF) in the Cebpb-mRNA. Here, we describe that reduced C/EBPβ-LIP expression due to genetic ablation of the uORF delays the development of age-associated phenotypes in mice. Moreover, female C/EBPβΔuORF mice display an extended lifespan. Since LIP levels increase upon aging in wild type mice, our data reveal an important role for C/EBPβ in the aging process and suggest that restriction of LIP expression sustains health and fitness. Thus, therapeutic strategies targeting C/EBPβ-LIP may offer new possibilities to treat age-related diseases and to prolong healthspan. The risks of major diseases including type II diabetes, cancer and Alzheimer’s are linked to the biological process of ageing. By finding ways to slow ageing, we can help more people to live longer healthier lives while avoiding these illnesses. Placing some animals on a diet that contains only two-thirds as many calories as they would normally eat can improve their fitness during old age and delay the onset of many age-related problems. It is unrealistic to expect people to control their diet to this extent, yet there may be other ways to bring about the same effects. Calorie restriction affects the activity of many different genes; for example, it causes a gene that produces a protein known as Liver-enriched Inhibitory Protein (LIP for short) to shut down. LIP controls the activity of many genes involved in metabolism, so it could be a key target for drugs to control ageing. Müller, Zidek et al. used mice that are unable to produce LIP to study this protein’s effect on ageing. The life expectancy of female mice lacking LIP increased by up to 20%. These mice were leaner, fitter, more resistant to cancer, had stronger immune systems and controlled their blood sugar levels better than normal mice. Male mice that lacked LIP did not live longer but did experience some ageing-related benefits. Genetic analysis also showed that gene activity particularly of metabolic genes is more robust in old female LIP-deficient mice and thus more similar to young control mice than old control mice. The results presented by Müller, Zidek et al. suggest that targeting the activity of the LIP gene could help to slow the ageing process. It is not yet clear whether shutting off LIP has similar beneficial effects in humans. Further research is also needed to investigate why female mice gain more benefits from a lack of LIP than males do.
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Affiliation(s)
- Christine Müller
- European Research Institute for the Biology of Ageing, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands.,Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Laura M Zidek
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Tobias Ackermann
- European Research Institute for the Biology of Ageing, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands
| | - Tristan de Jong
- European Research Institute for the Biology of Ageing, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands
| | - Peng Liu
- Institute for Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Verena Kliche
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Mohamad Amr Zaini
- European Research Institute for the Biology of Ageing, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands
| | - Gertrud Kortman
- European Research Institute for the Biology of Ageing, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands
| | - Liesbeth Harkema
- Dutch Molecular Pathology Centre, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Dineke S Verbeek
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Jan P Tuckermann
- Institute for Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | | | - Alain de Bruin
- Dutch Molecular Pathology Centre, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.,Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Victor Guryev
- European Research Institute for the Biology of Ageing, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands
| | - Zhao-Qi Wang
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Cornelis F Calkhoven
- European Research Institute for the Biology of Ageing, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands.,Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
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11
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Guillory B, Jawanmardi N, Iakova P, Anderson B, Zang P, Timchenko NA, Garcia JM. Ghrelin deletion protects against age-associated hepatic steatosis by downregulating the C/EBPα-p300/DGAT1 pathway. Aging Cell 2018; 17. [PMID: 29024407 PMCID: PMC5771394 DOI: 10.1111/acel.12688] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2017] [Indexed: 12/13/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. NAFLD usually begins as low‐grade hepatic steatosis which further progresses in an age‐dependent manner to nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma in some patients. Ghrelin is a hormone known to promote adiposity in rodents and humans, but its potential role in hepatic steatosis is unknown. We hypothesized that genetic ghrelin deletion will protect against the development of age‐related hepatic steatosis. To examine this hypothesis, we utilized ghrelin knockout (KO) mice. Although no different in young animals (3 months old), we found that at 20 months of age, ghrelin KO mice have significantly reduced hepatic steatosis compared to aged‐matched wild‐type (WT) mice. Examination of molecular pathways by which deletion of ghrelin reduces steatosis showed that the increase in expression of diacylglycerol O‐acyltransferase‐1 (DGAT1), one of the key enzymes of triglyceride (TG) synthesis, seen with age in WT mice, is not present in KO mice. This was due to the lack of activation of CCAAT/enhancer binding protein‐alpha (C/EBPα) protein and subsequent reduction of C/EBPα‐p300 complexes. These complexes were abundant in livers of old WT mice and were bound to and activated the DGAT1 promoter. However, the C/EBPα‐p300 complexes were not detected on the DGAT1 promoter in livers of old KO mice resulting in lower levels of the enzyme. In conclusion, these studies demonstrate the mechanism by which ghrelin deletion prevents age‐associated hepatic steatosis and suggest that targeting this pathway may offer therapeutic benefit for NAFLD.
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Affiliation(s)
- Bobby Guillory
- Department of Medicine; Baylor College of Medicine; Division of Endocrinology; Diabetes and Metabolism, MCL; Center for Translational Research in Inflammatory Diseases; Michael E. DeBakey Veterans Affairs Medical Center; Houston TX 77030 USA
- Huffington Center on Aging; Baylor College of Medicine; Houston TX 77030 USA
| | - Nicole Jawanmardi
- Huffington Center on Aging; Baylor College of Medicine; Houston TX 77030 USA
- Department of Pathology and Immunology; Baylor College of Medicine; Houston TX 77030 USA
| | - Polina Iakova
- Huffington Center on Aging; Baylor College of Medicine; Houston TX 77030 USA
- Department of Pathology and Immunology; Baylor College of Medicine; Houston TX 77030 USA
| | - Barbara Anderson
- GRECC; VA Puget Sound Health Care System; University of Washington; Seattle WA 98108 USA
| | - Pu Zang
- GRECC; VA Puget Sound Health Care System; University of Washington; Seattle WA 98108 USA
- Department of Endocrinology; Nanjing Jinling Hospital; Nanjing 210002 China
| | - Nikolai A. Timchenko
- Huffington Center on Aging; Baylor College of Medicine; Houston TX 77030 USA
- Department of Pathology and Immunology; Baylor College of Medicine; Houston TX 77030 USA
- Cincinnati Children's Hospital Medical Center; Cincinnati OH 45229 USA
| | - Jose M. Garcia
- Department of Medicine; Baylor College of Medicine; Division of Endocrinology; Diabetes and Metabolism, MCL; Center for Translational Research in Inflammatory Diseases; Michael E. DeBakey Veterans Affairs Medical Center; Houston TX 77030 USA
- Huffington Center on Aging; Baylor College of Medicine; Houston TX 77030 USA
- GRECC; VA Puget Sound Health Care System; University of Washington; Seattle WA 98108 USA
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12
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Varricchio L, Falchi M, Dall'Ora M, De Benedittis C, Ruggeri A, Uversky VN, Migliaccio AR. Calreticulin: Challenges Posed by the Intrinsically Disordered Nature of Calreticulin to the Study of Its Function. Front Cell Dev Biol 2017; 5:96. [PMID: 29218307 PMCID: PMC5703715 DOI: 10.3389/fcell.2017.00096] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 10/31/2017] [Indexed: 12/16/2022] Open
Abstract
Calreticulin is a Ca2+-binding chaperone protein, which resides mainly in the endoplasmic reticulum but also found in other cellular compartments including the plasma membrane. In addition to Ca2+, calreticulin binds and regulates almost all proteins and most of the mRNAs deciding their intracellular fate. The potential functions of calreticulin are so numerous that identification of all of them is becoming a nightmare. Still the recent discovery that patients affected by the Philadelphia-negative myeloproliferative disorders essential thrombocytemia or primary myelofibrosis not harboring JAK2 mutations carry instead calreticulin mutations disrupting its C-terminal domain has highlighted the clinical need to gain a deeper understanding of the biological activity of this protein. However, by contrast with other proteins, such as enzymes or transcription factors, the biological functions of which are strictly defined by a stable spatial structure imprinted by their amino acid sequence, calreticulin contains intrinsically disordered regions, the structure of which represents a highly dynamic conformational ensemble characterized by constant changes between several metastable conformations in response to a variety of environmental cues. This article will illustrate the Theory of calreticulin as an intrinsically disordered protein and discuss the Hypothesis that the dynamic conformational changes to which calreticulin may be subjected by environmental cues, by promoting or restricting the exposure of its active sites, may affect its function under normal and pathological conditions.
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Affiliation(s)
- Lilian Varricchio
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Mario Falchi
- National HIV/AIDS Center, Istituto Superiore Sanità, Rome, Italy
| | - Massimiliano Dall'Ora
- Department of Biomedical and Neuromotorial Sciences, Alma Mater University, Bologna, Italy
| | - Caterina De Benedittis
- Department of Biomedical and Neuromotorial Sciences, Alma Mater University, Bologna, Italy
| | - Alessandra Ruggeri
- Department of Biomedical and Neuromotorial Sciences, Alma Mater University, Bologna, Italy
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.,Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Russia
| | - Anna Rita Migliaccio
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Department of Biomedical and Neuromotorial Sciences, Alma Mater University, Bologna, Italy
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13
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Multi-omics Comparative Analysis Reveals Multiple Layers of Host Signaling Pathway Regulation by the Gut Microbiota. mSystems 2017; 2:mSystems00107-17. [PMID: 29085914 PMCID: PMC5655592 DOI: 10.1128/msystems.00107-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 09/29/2017] [Indexed: 02/06/2023] Open
Abstract
Multiple host pathways were affected by its adaptation to the microbiota. We have found significant transcriptome-proteome discordance caused by the microbiota. This discovery leads to the definite conclusion that transcript-level analysis is not sufficient to predict protein levels and their influence on the function of many specific cellular pathways, so only analysis of combinations of the quantitative data determined at different levels will lead to a complete understanding of the complex relationships between the host and the microbiota. Therefore, our results demonstrate the importance of using an integrative approach to study host-microbiota interaction at the molecular level. The bodies of mammals are hosts to vast microbial communities composed of trillions of bacteria from thousands of species, whose effects on health and development have begun to be appreciated only recently. In this investigation, an integrated analysis combining proteomics and transcriptomics was used to quantitatively compare the terminal ilia from conventional and germfree mice. Female and male mice responded similarly to the microbiota, but C57BL/10A mice responded more strongly than BALB/c mice at both the transcriptome and proteome levels. The microbiota primarily caused upregulation of immunological pathways and downregulation of metabolic pathways in the conventional mice. Many of the affected pathways were altered only at either the transcriptome or proteome level. Of the pathways that were affected at both levels, most were affected concordantly. The discordant pathways were not principally involved in the immune system but instead were related to metabolism, oxidative phosphorylation, protein translation, transport, and turnover. To broaden the discovery of affected host pathways, a meta-analysis was performed using intestinal transcriptomics data from previously published studies of germfree versus conventional mice with diverse microbiota populations. Similar transcript-level responses to the microbiota were found, and many additional affected host pathways were discovered. IMPORTANCE Multiple host pathways were affected by its adaptation to the microbiota. We have found significant transcriptome-proteome discordance caused by the microbiota. This discovery leads to the definite conclusion that transcript-level analysis is not sufficient to predict protein levels and their influence on the function of many specific cellular pathways, so only analysis of combinations of the quantitative data determined at different levels will lead to a complete understanding of the complex relationships between the host and the microbiota. Therefore, our results demonstrate the importance of using an integrative approach to study host-microbiota interaction at the molecular level.
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14
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RNA Binding Protein CUGBP1 Inhibits Liver Cancer in a Phosphorylation-Dependent Manner. Mol Cell Biol 2017; 37:MCB.00128-17. [PMID: 28559429 DOI: 10.1128/mcb.00128-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/20/2017] [Indexed: 01/10/2023] Open
Abstract
Despite intensive investigations, mechanisms of liver cancer are not known. Here, we identified an important step of liver cancer, which is the neutralization of tumor suppressor activities of an RNA binding protein, CUGBP1. The translational activity of CUGBP1 is activated by dephosphorylation at Ser302. We generated CUGBP1-S302A knock-in mice and found that the reduction of translational activity of CUGBP1 causes development of a fatty liver phenotype in young S302A mice. Examination of liver cancer in diethylnitrosamine (DEN)-treated CUGBP1-S302A mice showed these mice develop much more severe liver cancer that is associated with elimination of the mutant CUGBP1. Searching for mechanisms of this elimination, we found that the oncoprotein gankyrin (Gank) preferentially binds to and triggers degradation of dephosphorylated CUGBP1 (de-ph-S302-CUGBP1) or S302A mutant CUGBP1. To test the role of Gank in degradation of CUGBP1, we generated mice with liver-specific deletion of Gank. In these mice, the tumor suppressor isoform of CUGBP1 is protected from Gank-mediated degradation. Consistent with reduction of CUGBP1 in animal models, CUGBP1 is reduced in patients with pediatric liver cancer. Thus, this work presents evidence that de-ph-S302-CUGBP1 is a tumor suppressor protein and that the Gank-UPS-mediated reduction of CUGBP1 is a key event in the development of liver cancer.
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15
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Kim C, Kang D, Lee EK, Lee JS. Long Noncoding RNAs and RNA-Binding Proteins in Oxidative Stress, Cellular Senescence, and Age-Related Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:2062384. [PMID: 28811863 PMCID: PMC5547732 DOI: 10.1155/2017/2062384] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/27/2017] [Accepted: 06/06/2017] [Indexed: 12/12/2022]
Abstract
Cellular senescence is a complex biological process that leads to irreversible cell-cycle arrest. Various extrinsic and intrinsic insults are associated with the onset of cellular senescence and frequently accompany genomic or epigenomic alterations. Cellular senescence is believed to contribute to tumor suppression, immune response, and tissue repair as well as aging and age-related diseases. Long noncoding RNAs (lncRNAs) are >200 nucleotides long, poorly conserved, and transcribed in a manner similar to that of mRNAs. They are tightly regulated during various cellular and physiological processes. Although many lncRNAs and their functional roles are still undescribed, the importance of lncRNAs in a variety of biological processes is widely recognized. RNA-binding proteins (RBPs) have a pivotal role in posttranscriptional regulation as well as in mRNA transport, storage, turnover, and translation. RBPs interact with mRNAs, other RBPs, and noncoding RNAs (ncRNAs) including lncRNAs, and they are involved in the regulation of a broad spectrum of cellular processes. Like other cell fate regulators, lncRNAs and RBPs, separately or cooperatively, are implicated in initiation and maintenance of cellular senescence, aging, and age-related diseases. Here, we review the current understanding of both lncRNAs and RBPs and their association with oxidative stress, senescence, and age-related diseases.
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Affiliation(s)
- Chongtae Kim
- Department of Biochemistry, The Catholic University of Korea College of Medicine, Seoul 06591, Republic of Korea
| | - Donghee Kang
- Department of Molecular Medicine and Hypoxia-Related Disease Research Center, Inha University College of Medicine, Incheon 22212, Republic of Korea
| | - Eun Kyung Lee
- Department of Biochemistry, The Catholic University of Korea College of Medicine, Seoul 06591, Republic of Korea
| | - Jae-Seon Lee
- Department of Molecular Medicine and Hypoxia-Related Disease Research Center, Inha University College of Medicine, Incheon 22212, Republic of Korea
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16
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A screening strategy for the discovery of drugs that reduce C/EBPβ-LIP translation with potential calorie restriction mimetic properties. Sci Rep 2017; 7:42603. [PMID: 28198412 PMCID: PMC5309760 DOI: 10.1038/srep42603] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/11/2017] [Indexed: 11/09/2022] Open
Abstract
An important part of the beneficial effects of calorie restriction (CR) on healthspan and lifespan is mediated through regulation of protein synthesis that is under control of the mechanistic target of rapamycin complex 1 (mTORC1). As one of its activities, mTORC1 stimulates translation into the metabolic transcription factor CCAAT/Enhancer Binding Protein β (C/EBPβ) isoform Liver-specific Inhibitory Protein (LIP). Regulation of LIP expression strictly depends on a translation re-initiation event that requires a conserved cis-regulatory upstream open reading frame (uORF) in the C/EBPβ-mRNA. We showed before that suppression of LIP in mice, reflecting reduced mTORC1-signaling at the C/EBPβ level, results in CR-type of metabolic improvements. Hence, we aim to find possibilities to pharmacologically down-regulate LIP in order to induce CR-mimetic effects. We engineered a luciferase-based cellular reporter system that acts as a surrogate for C/EBPβ-mRNA translation, emulating uORF-dependent C/EBPβ-LIP expression under different translational conditions. By using the reporter system in a high-throughput screening (HTS) strategy we identified drugs that reduce LIP. The drug Adefovir Dipivoxil passed all counter assays and increases fatty acid β-oxidation in a hepatoma cell line in a LIP-dependent manner. Therefore, these drugs that suppress translation into LIP potentially exhibit CR-mimetic properties.
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17
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CUG-binding protein 1 regulates HSC activation and liver fibrogenesis. Nat Commun 2016; 7:13498. [PMID: 27853137 PMCID: PMC5118555 DOI: 10.1038/ncomms13498] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 10/07/2016] [Indexed: 12/17/2022] Open
Abstract
Excessive activation of hepatic stellate cells (HSCs) is a key step in liver fibrogenesis. Here we report that CUG-binding protein 1 (CUGBP1) expression is elevated in HSCs and positively correlates with liver fibrosis severity in human liver biopsies. Transforming growth factor-beta (TGF-β) selectively increases CUGBP1 expression in cultured HSCs in a p38 mitogen-activated protein kinase (MAPK)-dependent manner. Knockdown of CUGBP1 inhibits alpha smooth muscle actin (α-SMA) expression and promotes interferon gamma (IFN-γ) production in HSCs in vitro. We further show that CUGBP1 specifically binds to the 3′ untranslated region (UTR) of human IFN-γ mRNA and promotes its decay. In mice, knockdown of CUGBP1 alleviates, whereas its overexpression exacerbates, bile duct ligation (BDL)-induced hepatic fibrosis. Therefore, CUGBP1-mediated IFN-γ mRNA decay is a key event for profibrotic TGF-β-dependent activation of HSCs, and inhibiting CUGBP1 to promote IFN-γ signalling in activated HSCs could be a novel strategy to treat liver fibrosis. Activation of hepatic stellate cells is a critical event in the development of fibrosis, which is driven by TGF-beta and inhibited by IFN-gamma. Here Wu et al. show that the RNA binding protein CUGBP1 is increased by TGF-beta signalling and promotes IFN-gamma mRNA degradation.
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18
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Fang T, Cui M, Sun J, Ge C, Zhao F, Zhang L, Tian H, Zhang L, Chen T, Jiang G, Xie H, Cui Y, Yao M, Li H, Li J. Orosomucoid 2 inhibits tumor metastasis and is upregulated by CCAAT/enhancer binding protein β in hepatocellular carcinomas. Oncotarget 2016; 6:16106-19. [PMID: 25965830 PMCID: PMC4599259 DOI: 10.18632/oncotarget.3867] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 03/31/2015] [Indexed: 12/19/2022] Open
Abstract
Cancer metastasis is a complex process, and the incidence of metastasis is influenced by many biological factors. Orosomucoid 2 (ORM2) is an important glycoprotein that is mainly biosynthesized and secreted by hepatocytes. As an acute-phase protein, ORM2 likely plays important roles in anti-inflammation, immunomodulation and drug delivery. However, little is known regarding the function of ORM2 in hepatocellular carcinoma (HCC). In this study, we determined that ORM2 expression in HCC tissues was negatively associated with intrahepatic metastasis and histological grade. Moreover, the ectopic overexpression of ORM2 decreased HCC cell migration and invasion in vitro and intrahepatic metastasis in vivo, whereas silencing ORM2 expression resulted in increased tumor cell migration and invasion in vitro. The CCAAT/enhancer binding protein β (C/EBPβ) upregulated ORM2 expression, while only the LAP1/2 (C/EBPβ isoforms) possessed transcription-promoting activity on the ORM2 promoter. Subsequently, we found that LAP1 repressed HCC cell migration and invasion via the induction of ORM2 expression. Consistently, the protein expression of C/EBPβ was negatively associated with histological grade and positively correlated with ORM2 protein expression in HCC tissues. Collectively, our findings indicate that ORM2 is a functional downstream target of C/EBPβ and functions as a tumor suppressor in HCC.
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Affiliation(s)
- Tao Fang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Meiling Cui
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Ji Sun
- Shanghai Medical Colloge, Fudan University, Shanghai, China
| | - Chao Ge
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Fangyu Zhao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Lin Zhang
- Shanghai Medical Colloge, Fudan University, Shanghai, China
| | - Hua Tian
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Lixing Zhang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Taoyang Chen
- Qi Dong Liver Cancer Institute, Qi Dong, Jiangsu Province, China
| | - Guoping Jiang
- Department of General Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Haiyang Xie
- Department of General Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Ying Cui
- Cancer Institute of Guangxi, Nanning, China
| | - Ming Yao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hong Li
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jinjun Li
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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19
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Blech-Hermoni Y, Dasgupta T, Coram RJ, Ladd AN. Identification of Targets of CUG-BP, Elav-Like Family Member 1 (CELF1) Regulation in Embryonic Heart Muscle. PLoS One 2016; 11:e0149061. [PMID: 26866591 PMCID: PMC4750973 DOI: 10.1371/journal.pone.0149061] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 12/30/2015] [Indexed: 01/17/2023] Open
Abstract
CUG-BP, Elav-like family member 1 (CELF1) is a highly conserved RNA binding protein that regulates pre-mRNA alternative splicing, polyadenylation, mRNA stability, and translation. In the heart, CELF1 is expressed in the myocardium, where its levels are tightly regulated during development. CELF1 levels peak in the heart during embryogenesis, and aberrant up-regulation of CELF1 in the adult heart has been implicated in cardiac pathogenesis in myotonic dystrophy type 1, as well as in diabetic cardiomyopathy. Either inhibition of CELF activity or over-expression of CELF1 in heart muscle causes cardiomyopathy in transgenic mice. Nonetheless, many of the cardiac targets of CELF1 regulation remain unknown. In this study, to identify cardiac targets of CELF1 we performed cross-linking immunoprecipitation (CLIP) for CELF1 from embryonic day 8 chicken hearts. We identified a previously unannotated exon in MYH7B as a novel target of CELF1-mediated regulation. We demonstrated that knockdown of CELF1 in primary chicken embryonic cardiomyocytes leads to increased inclusion of this exon and decreased MYH7B levels. We also investigated global changes in the transcriptome of primary embryonic cardiomyocytes following CELF1 knockdown in a published RNA-seq dataset. Pathway and network analyses identified strong associations between CELF1 and regulation of cell cycle and translation. Important regulatory proteins, including both RNA binding proteins and a cardiac transcription factor, were affected by loss of CELF1. Together, these data suggest that CELF1 is a key regulator of cardiomyocyte gene expression.
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Affiliation(s)
- Yotam Blech-Hermoni
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Program in Cell Biology, Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Twishasri Dasgupta
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Ryan J. Coram
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Andrea N. Ladd
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Program in Cell Biology, Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- * E-mail:
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20
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Vlasova-St Louis I, Bohjanen PR. Feedback Regulation of Kinase Signaling Pathways by AREs and GREs. Cells 2016; 5:cells5010004. [PMID: 26821046 PMCID: PMC4810089 DOI: 10.3390/cells5010004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 01/20/2016] [Accepted: 01/20/2016] [Indexed: 12/18/2022] Open
Abstract
In response to environmental signals, kinases phosphorylate numerous proteins, including RNA-binding proteins such as the AU-rich element (ARE) binding proteins, and the GU-rich element (GRE) binding proteins. Posttranslational modifications of these proteins lead to a significant changes in the abundance of target mRNAs, and affect gene expression during cellular activation, proliferation, and stress responses. In this review, we summarize the effect of phosphorylation on the function of ARE-binding proteins ZFP36 and ELAVL1 and the GRE-binding protein CELF1. The networks of target mRNAs that these proteins bind and regulate include transcripts encoding kinases and kinase signaling pathways (KSP) components. Thus, kinase signaling pathways are involved in feedback regulation, whereby kinases regulate RNA-binding proteins that subsequently regulate mRNA stability of ARE- or GRE-containing transcripts that encode components of KSP.
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Affiliation(s)
- Irina Vlasova-St Louis
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Paul R Bohjanen
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
- Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis, MN 55455, USA.
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA.
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21
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DJ-1 deficiency alleviates steatosis in cultured hepatocytes. BIOTECHNOL BIOPROC E 2016. [DOI: 10.1007/s12257-015-0689-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Pulido-Salgado M, Vidal-Taboada JM, Saura J. C/EBPβ and C/EBPδ transcription factors: Basic biology and roles in the CNS. Prog Neurobiol 2015; 132:1-33. [PMID: 26143335 DOI: 10.1016/j.pneurobio.2015.06.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 05/08/2015] [Accepted: 06/16/2015] [Indexed: 02/01/2023]
Abstract
CCAAT/enhancer binding protein (C/EBP) β and C/EBPδ are transcription factors of the basic-leucine zipper class which share phylogenetic, structural and functional features. In this review we first describe in depth their basic molecular biology which includes fascinating aspects such as the regulated use of alternative initiation codons in the C/EBPβ mRNA. The physical interactions with multiple transcription factors which greatly opens the number of potentially regulated genes or the presence of at least five different types of post-translational modifications are also remarkable molecular mechanisms that modulate C/EBPβ and C/EBPδ function. In the second part, we review the present knowledge on the localization, expression changes and physiological roles of C/EBPβ and C/EBPδ in neurons, astrocytes and microglia. We conclude that C/EBPβ and C/EBPδ share two unique features related to their role in the CNS: whereas in neurons they participate in memory formation and synaptic plasticity, in glial cells they regulate the pro-inflammatory program. Because of their role in neuroinflammation, C/EBPβ and C/EBPδ in microglia are potential targets for treatment of neurodegenerative disorders. Any strategy to reduce C/EBPβ and C/EBPδ activity in neuroinflammation needs to take into account its potential side-effects in neurons. Therefore, cell-specific treatments will be required for the successful application of this strategy.
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Affiliation(s)
- Marta Pulido-Salgado
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain
| | - Jose M Vidal-Taboada
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain
| | - Josep Saura
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain.
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23
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Falick Michaeli T, Bergman Y, Gielchinsky Y. Rejuvenating effect of pregnancy on the mother. Fertil Steril 2015; 103:1125-8. [PMID: 25813291 DOI: 10.1016/j.fertnstert.2015.02.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 02/23/2015] [Accepted: 02/23/2015] [Indexed: 01/10/2023]
Abstract
Aging is associated with reduced tissue regenerative capacity. In recent years, studies in mice have shown that transfusion of blood from young animals to old ones can reverse some aging effects and increase regenerative potential similar to that seen in young animals. Because pregnancy is a unique biological model of a partially shared blood system, we have speculated that pregnancy would have a rejuvenating effect on the mother. Recent studies support this idea. In this review, we will summarize the current knowledge of the rejuvenating effect of pregnancy on the mother.
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Affiliation(s)
- Tal Falick Michaeli
- Rubin Chair in Medical Science, Department of Developmental Biology and Cancer Research, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Yehudit Bergman
- Rubin Chair in Medical Science, Department of Developmental Biology and Cancer Research, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Yuval Gielchinsky
- Rubin Chair in Medical Science, Department of Developmental Biology and Cancer Research, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel; Department of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
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24
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The kinase MST4 limits inflammatory responses through direct phosphorylation of the adaptor TRAF6. Nat Immunol 2015; 16:246-57. [DOI: 10.1038/ni.3097] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/05/2015] [Indexed: 12/15/2022]
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25
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Zhou Y, Ma H, Fang J, Lian M, Feng L, Wang R. Knockdown of CUG-binding protein 1 induces apoptosis of human laryngeal cancer cells. Cell Biol Int 2014; 38:1408-14. [PMID: 25077823 DOI: 10.1002/cbin.10356] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 05/28/2014] [Indexed: 01/10/2023]
Affiliation(s)
- Yi Zhou
- Department of Otolaryngology; Head and Neck Surgery; Beijing TongRen Hospital; Capital Medical University; Beijing 100730 China
- Department of Otolaryngology; Head and Neck Surgery; The First Affiliated Hospital of Xiamen University; Xiamen 361003 China
| | - Hongzhi Ma
- Department of Otolaryngology; Head and Neck Surgery; Beijing TongRen Hospital; Capital Medical University; Beijing 100730 China
| | - Jugao Fang
- Department of Otolaryngology; Head and Neck Surgery; Beijing TongRen Hospital; Capital Medical University; Beijing 100730 China
| | - Meng Lian
- Department of Otolaryngology; Head and Neck Surgery; Beijing TongRen Hospital; Capital Medical University; Beijing 100730 China
| | - Ling Feng
- Department of Otolaryngology; Head and Neck Surgery; Beijing TongRen Hospital; Capital Medical University; Beijing 100730 China
| | - Ru Wang
- Department of Otolaryngology; Head and Neck Surgery; Beijing TongRen Hospital; Capital Medical University; Beijing 100730 China
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26
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Cardani R, Giagnacovo M, Rossi G, Renna LV, Bugiardini E, Pizzamiglio C, Botta A, Meola G. Progression of muscle histopathology but not of spliceopathy in myotonic dystrophy type 2. Neuromuscul Disord 2014; 24:1042-53. [PMID: 25139674 DOI: 10.1016/j.nmd.2014.06.435] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/07/2014] [Accepted: 06/17/2014] [Indexed: 12/25/2022]
Abstract
Myotonic dystrophy type 2 (DM2) is an autosomal dominant progressive disease involving skeletal and cardiac muscle and brain. It is caused by a tetranucleotide repeat within the first intron of the CNBP gene that leads to an alteration of the alternative splicing of several genes. To understand the molecular mechanisms that play a role in DM2 progression, the evolution of skeletal muscle histopathology and biomolecular findings in successive biopsies have been studied. Biceps brachii biopsies from 5 DM2 patients who underwent two successive biopsies at different years of age have been used. Muscle histopathology has been assessed on sections immunostained with fast or slow myosin. FISH in combination with MBNL1-immunofluorescence has been performed to evaluate ribonuclear inclusion and MBNL1 foci dimensions in myonuclei. Gene and protein expression and alteration of alternative splicing of several genes have been evaluated over time. All DM2 patients examined show a worsening of muscle histopathology and an increase of foci dimensions over time. The progressive worsening of myotonia in DM2 patients may be due to the decrease of CLCN1 mRNA observed in all patients examined. However, a worsening of alternative splicing alterations has not been evidenced over time. The data obtained in this study confirm that DM2 is a slow progression disease since histological and biomolecular alterations observed in skeletal muscle are minimal even after 10-year interval. The data indicate that muscle morphological alterations evolve more rapidly over time than the molecular changes thus indicating that muscle biopsy is a more sensitive tool than biomolecular markers to assess disease progression at muscle level.
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Affiliation(s)
- Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, Milan, Italy
| | - Marzia Giagnacovo
- Department of Biology and Biotechnologies, University of Pavia, Pavia, Italy
| | - Giulia Rossi
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Laura V Renna
- Department of Biosciences, University of Milan, Milan, Italy
| | - Enrico Bugiardini
- Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy
| | - Chiara Pizzamiglio
- Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy
| | - Annalisa Botta
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Giovanni Meola
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, Milan, Italy; Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy.
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Wojciechowska M, Taylor K, Sobczak K, Napierala M, Krzyzosiak WJ. Small molecule kinase inhibitors alleviate different molecular features of myotonic dystrophy type 1. RNA Biol 2014; 11:742-54. [PMID: 24824895 PMCID: PMC4156505 DOI: 10.4161/rna.28799] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Expandable (CTG)n repeats in the 3′ UTR of the DMPK gene are a cause of myotonic dystrophy type 1 (DM1), which leads to a toxic RNA gain-of-function disease. Mutant RNAs with expanded CUG repeats are retained in the nucleus and aggregate in discrete inclusions. These foci sequester splicing factors of the MBNL family and trigger upregulation of the CUGBP family of proteins resulting in the mis-splicing of their target transcripts. To date, many efforts to develop novel therapeutic strategies have been focused on disrupting the toxic nuclear foci and correcting aberrant alternative splicing via targeting mutant CUG repeats RNA; however, no effective treatment for DM1 is currently available. Herein, we present results of culturing of human DM1 myoblasts and fibroblasts with two small-molecule ATP-binding site-specific kinase inhibitors, C16 and C51, which resulted in the alleviation of the dominant-negative effects of CUG repeat expansion. Reversal of the DM1 molecular phenotype includes a reduction of the size and number of foci containing expanded CUG repeat transcripts, decreased steady-state levels of CUGBP1 protein, and consequent improvement of the aberrant alternative splicing of several pre-mRNAs misregulated in DM1.
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Affiliation(s)
- Marzena Wojciechowska
- Department of Molecular Biomedicine; Institute of Bioorganic Chemistry; Polish Academy of Sciences; Noskowskiego; Poznan, Poland
| | - Katarzyna Taylor
- Department of Gene Expression; Institute of Molecular Biology and Biotechnology; Adam Mickiewicz University; Umultowska 89; Poznan, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression; Institute of Molecular Biology and Biotechnology; Adam Mickiewicz University; Umultowska 89; Poznan, Poland
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics and UAB Stem Cell Institute; University of Alabama at Birmingham; Birmingham, AL USA
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine; Institute of Bioorganic Chemistry; Polish Academy of Sciences; Noskowskiego; Poznan, Poland
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Giudice J, Cooper TA. RNA-binding proteins in heart development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 825:389-429. [PMID: 25201112 DOI: 10.1007/978-1-4939-1221-6_11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
RNA-binding proteins (RBPs) are key players of posttranscriptional regulation occurring during normal tissue development. All tissues examined thus far have revealed the importance of RBPs in the regulation of complex networks involved in organ morphogenesis, maturation, and function. They are responsible for controlling tissue-specific gene expression by regulating alternative splicing, mRNA stability, translation, and poly-adenylation. The heart is the first organ form during embryonic development and is also the first to acquire functionality. Numerous remodeling processes take place during late cardiac development since fetal heart first adapts to birth and then undergoes a transition to adult functionality. This physiological remodeling involves transcriptional and posttranscriptional networks that are regulated by RBPs. Disruption of the normal regulatory networks has been shown to cause cardiomyopathy in humans and animal models. Here we review the complexity of late heart development and the current information regarding how RBPs control aspects of postnatal heart development. We also review how activities of RBPs are modulated adding complexity to the regulation of developmental networks.
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Affiliation(s)
- Jimena Giudice
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA,
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Wei C, Jones K, Timchenko NA, Timchenko L. GSK3β is a new therapeutic target for myotonic dystrophy type 1. Rare Dis 2013; 1:e26555. [PMID: 25003008 PMCID: PMC3927489 DOI: 10.4161/rdis.26555] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/16/2013] [Accepted: 09/20/2013] [Indexed: 12/31/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1), an incurable, neuromuscular disease, is caused by the expansion of CTG repeats within the 3′ UTR of DMPK on chromosome 19q. In DM1 patients, mutant DMPK transcripts deregulate RNA metabolism by altering CUG RNA-binding proteins. Several approaches have been proposed for DM1 therapy focused on specific degradation of the mutant CUG repeats or on correction of RNA-binding proteins, affected by CUG repeats. One such protein is CUG RNA-binding protein (CUGBP1). The ability of CUGBP1 to increase or inhibit translation depends on phosphorylation at Ser302, which is mediated by cyclin D3-CDK4. The mutant CUG repeats increase the levels of CUGBP1 protein and inhibit Ser302 phosphorylation, leading to the accumulation of CUGBP1 isoforms that repress translation (i.e., CUGBP1REP). Elevation of CUGBP1REP in DM1 is caused by increased GSK3β kinase, which reduces the cyclin D3-CDK4 pathway and subsequent phosphorylation of CUGBP1 at Ser302. In this review, we discuss our recent discovery showing that correction of GSK3β activity in the DM1 mouse model (i.e., HSALR mice) reduces DM1 muscle pathology. These findings demonstrate that GSK3β is a novel therapeutic target for treating DM1.
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Affiliation(s)
- Christina Wei
- Department of Molecular Physiology and Biophysics; Baylor College of Medicine; Houston, TX USA
| | - Karlie Jones
- Department of Molecular Physiology and Biophysics; Baylor College of Medicine; Houston, TX USA
| | - Nikolai A Timchenko
- Pathology and Immunology; Huffington Center on Aging; Baylor College of Medicine; Houston, TX USA
| | - Lubov Timchenko
- Department of Molecular Physiology and Biophysics; Baylor College of Medicine; Houston, TX USA
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Kim YK, Mandal M, Yadava RS, Paillard L, Mahadevan MS. Evaluating the effects of CELF1 deficiency in a mouse model of RNA toxicity. Hum Mol Genet 2013; 23:293-302. [PMID: 24001600 DOI: 10.1093/hmg/ddt419] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1), the most common form of adult-onset muscular dystrophy, is caused by an expanded (CTG)n repeat in the 3' untranslated region of the DM protein kinase (DMPK) gene. The toxic RNA transcripts produced from the mutant allele alter the function of RNA-binding proteins leading to the functional depletion of muscleblind-like (MBNL) proteins and an increase in steady state levels of CUG-BP1 (CUGBP-ETR-3 like factor 1, CELF1). The role of increased CELF1 in DM1 pathogenesis is well studied using genetically engineered mouse models. Also, as a potential therapeutic strategy, the benefits of increasing MBNL1 expression have recently been reported. However, the effect of reduction of CELF1 is not yet clear. In this study, we generated CELF1 knockout mice, which also carry an inducible toxic RNA transgene to test the effects of CELF1 reduction in RNA toxicity. We found that the absence of CELF1 did not correct splicing defects. It did however mitigate the increase in translational targets of CELF1 (MEF2A and C/EBPβ). Notably, we found that loss of CELF1 prevented deterioration of muscle function by the toxic RNA, and resulted in better muscle histopathology. These data suggest that while reduction of CELF1 may be of limited benefit with respect to DM1-associated spliceopathy, it may be beneficial to the muscular dystrophy associated with RNA toxicity.
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Affiliation(s)
- Yun Kyoung Kim
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
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Molecular mechanisms of muscle atrophy in myotonic dystrophies. Int J Biochem Cell Biol 2013; 45:2280-7. [PMID: 23796888 DOI: 10.1016/j.biocel.2013.06.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 06/11/2013] [Accepted: 06/12/2013] [Indexed: 02/01/2023]
Abstract
Myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2) are multisystemic diseases that primarily affect skeletal muscle, causing myotonia, muscle atrophy, and muscle weakness. DM1 and DM2 pathologies are caused by expansion of CTG and CCTG repeats in non-coding regions of the genes encoding myotonic dystrophy protein kinase (DMPK) and zinc finger protein 9 (ZNF9) respectively. These expansions cause DM pathologies through accumulation of mutant RNAs that alter RNA metabolism in patients' tissues by targeting RNA-binding proteins such as CUG-binding protein 1 (CUGBP1) and Muscle blind-like protein 1 (MBNL1). Despite overwhelming evidence showing the critical role of RNA-binding proteins in DM1 and DM2 pathologies, the downstream pathways by which these RNA-binding proteins cause muscle wasting and muscle weakness are not well understood. This review discusses the molecular pathways by which DM1 and DM2 mutations might cause muscle atrophy and describes progress toward the development of therapeutic interventions for muscle wasting and weakness in DM1 and DM2. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.
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32
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Edwards JM, Long J, de Moor CH, Emsley J, Searle MS. Structural insights into the targeting of mRNA GU-rich elements by the three RRMs of CELF1. Nucleic Acids Res 2013; 41:7153-66. [PMID: 23748565 PMCID: PMC3737555 DOI: 10.1093/nar/gkt470] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The CUG-BP, Elav-like family (CELF) of RNA-binding proteins control gene expression at a number of different levels by regulating pre-mRNA splicing, deadenylation and mRNA stability. We present structural insights into the binding selectivity of CELF member 1 (CELF1) for GU-rich mRNA target sequences of the general form 5'-UGUNxUGUNyUGU and identify a high affinity interaction (Kd ∼ 100 nM for x = 2 and y = 4) with simultaneous binding of all three RNA recognition motifs within a single 15-nt binding element. RNA substrates spin-labelled at either the 3' or 5' terminus result in differential nuclear magnetic resonance paramagnetic relaxation enhancement effects, which are consistent with a non-sequential 2-1-3 arrangement of the three RNA recognition motifs on UGU sites in a 5' to 3' orientation along the RNA target. We further demonstrate that CELF1 binds to dispersed single-stranded UGU sites at the base of an RNA hairpin providing a structural rationale for recognition of CUG expansion repeats and splice site junctions in the regulation of alternative splicing.
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Affiliation(s)
- John M Edwards
- School of Chemistry, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
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33
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Gaya M, Repetto V, Toneatto J, Anesini C, Piwien-Pilipuk G, Moreno S. Antiadipogenic effect of carnosic acid, a natural compound present in Rosmarinus officinalis, is exerted through the C/EBPs and PPARγ pathways at the onset of the differentiation program. Biochim Biophys Acta Gen Subj 2013; 1830:3796-806. [DOI: 10.1016/j.bbagen.2013.03.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 02/21/2013] [Accepted: 03/20/2013] [Indexed: 01/24/2023]
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de Haro M, Al-Ramahi I, Jones KR, Holth JK, Timchenko LT, Botas J. Smaug/SAMD4A restores translational activity of CUGBP1 and suppresses CUG-induced myopathy. PLoS Genet 2013; 9:e1003445. [PMID: 23637619 PMCID: PMC3630084 DOI: 10.1371/journal.pgen.1003445] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 02/27/2013] [Indexed: 11/18/2022] Open
Abstract
We report the identification and characterization of a previously unknown suppressor of myopathy caused by expansion of CUG repeats, the mutation that triggers Myotonic Dystrophy Type 1 (DM1). We screened a collection of genes encoding RNA-binding proteins as candidates to modify DM1 pathogenesis using a well established Drosophila model of the disease. The screen revealed smaug as a powerful modulator of CUG-induced toxicity. Increasing smaug levels prevents muscle wasting and restores muscle function, while reducing its function exacerbates CUG-induced phenotypes. Using human myoblasts, we show physical interactions between human Smaug (SMAUG1/SMAD4A) and CUGBP1. Increased levels of SMAUG1 correct the abnormally high nuclear accumulation of CUGBP1 in myoblasts from DM1 patients. In addition, augmenting SMAUG1 levels leads to a reduction of inactive CUGBP1-eIF2α translational complexes and to a correction of translation of MRG15, a downstream target of CUGBP1. Therefore, Smaug suppresses CUG-mediated muscle wasting at least in part via restoration of translational activity of CUGBP1.
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Affiliation(s)
- Maria de Haro
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
| | - Ismael Al-Ramahi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
| | - Karlie R. Jones
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jerrah K. Holth
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lubov T. Timchenko
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Juan Botas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
- * E-mail:
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Blech-Hermoni Y, Stillwagon SJ, Ladd AN. Diversity and conservation of CELF1 and CELF2 RNA and protein expression patterns during embryonic development. Dev Dyn 2013; 242:767-77. [PMID: 23468433 DOI: 10.1002/dvdy.23959] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/18/2013] [Accepted: 02/20/2013] [Indexed: 01/21/2023] Open
Abstract
INTRODUCTION CUG-BP, Elav-like family member 1 (CELF1) and CELF2 are RNA-binding proteins that regulate several stages of RNA processing, and are broadly expressed in developing and adult tissues. In this study, we investigated the expression patterns of CELF1 and CELF2 transcripts and proteins in different tissues, stages of development, and organisms. RESULTS We found that CELF1 and CELF2 protein levels are regulated independently of transcript levels during heart development, and these proteins exhibit nuclear and cytoplasmic isoforms in the embryonic heart. We found that the subcellular distribution of CELF1 differs between heart, liver, nervous system, and eye, and identified tissue-specific isoforms of both CELF1 and CELF2 in these tissues. CELF1 and CELF2 are largely co-expressed, but are found in mutually exclusive territories in several organs, including the heart and eye. Finally, we show that the expression patterns observed in embryonic chicken were mostly recapitulated in the developing mouse, suggesting that the roles of these proteins in the tissues and cells of the developing embryo are conserved as well. CONCLUSIONS CELF1 and CELF2 may underlie conserved, developmentally regulated, tissue-specific processes in vertebrate embryos. Different tissues likely have unique profiles of nuclear and cytoplasmic CELF1- and CELF2-mediated functions.
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Affiliation(s)
- Y Blech-Hermoni
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
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Jin J, Iakova P, Jiang Y, Lewis K, Sullivan E, Jawanmardi N, Donehower L, Timchenko L, Timchenko NA. Transcriptional and translational regulation of C/EBPβ-HDAC1 protein complexes controls different levels of p53, SIRT1, and PGC1α proteins at the early and late stages of liver cancer. J Biol Chem 2013; 288:14451-14462. [PMID: 23564453 DOI: 10.1074/jbc.m113.460840] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cancer changes biological processes in the liver by altering gene expression at the levels of transcription, translation, and protein modification. The RNA binding protein CUGBP1 is a key regulator of translation of CCAAT enhancer binding protein β and histone deacetylase 1 (HDAC1). These proteins form complexes that are involved in the regulation of liver biology. Here we show a critical role of the translational activation of CCAAT/enhancer binding protein β-HDAC1 complexes in the development of liver cancer mediated by diethylnitrosamine. We found that diethylnitrosamine increases the levels of CUGBP1 and activates CUGBP1 by phosphorylation, leading to the formation of the CUGBP1-eIF2 complex, which is an activator of translation of CUGBP1-dependent mRNAs. The elevation of the CUGBP1-eIF2 complex increases translation of C/EBPβ and HDAC1, resulting in an increase of C/EBPβ-HDAC1 complexes at later stages of liver cancer. We found that C/EBPβ-HDAC1 complexes repress promoters of three key regulators of liver functions: p53, SIRT1, and PGC1α. As the result of this suppression, the p53-, SIRT1-, and PGC1α-dependent downstream pathways are reduced, leading to increased liver proliferation. We also found that the proper regulation of C/EBPβ-HDAC1 complexes is required for the maintenance of biological levels of p53, SIRT1, and PGC1α in quiescent livers and at early stages of liver cancer. Taken together, these studies showed that the development of liver cancer includes a tight regulation of levels of C/EBPβ-HDAC1 complexes on the levels of transcription, translation, and posttranslational modifications.
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Affiliation(s)
- Jingling Jin
- Huffington Center on Aging and Department of Huffington Center on Aging and Departments of Pathology and Immunology, Virology, and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Polina Iakova
- Huffington Center on Aging and Department of Huffington Center on Aging and Departments of Pathology and Immunology, Virology, and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Yanjun Jiang
- Huffington Center on Aging and Department of Huffington Center on Aging and Departments of Pathology and Immunology, Virology, and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Kyle Lewis
- Huffington Center on Aging and Department of Huffington Center on Aging and Departments of Pathology and Immunology, Virology, and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Emily Sullivan
- Huffington Center on Aging and Department of Huffington Center on Aging and Departments of Pathology and Immunology, Virology, and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Nicole Jawanmardi
- Huffington Center on Aging and Department of Huffington Center on Aging and Departments of Pathology and Immunology, Virology, and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Lawrence Donehower
- Huffington Center on Aging and Department of Huffington Center on Aging and Departments of Pathology and Immunology, Virology, and Microbiology, Baylor College of Medicine, Houston, Texas 77030
| | - Lubov Timchenko
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030
| | - Nikolai A Timchenko
- Huffington Center on Aging and Department of Huffington Center on Aging and Departments of Pathology and Immunology, Virology, and Microbiology, Baylor College of Medicine, Houston, Texas 77030.
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Jin J, Iakova P, Breaux M, Sullivan E, Jawanmardi N, Chen D, Jiang Y, Medrano EM, Timchenko NA. Increased expression of enzymes of triglyceride synthesis is essential for the development of hepatic steatosis. Cell Rep 2013; 3:831-43. [PMID: 23499441 DOI: 10.1016/j.celrep.2013.02.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 12/12/2012] [Accepted: 02/06/2013] [Indexed: 12/14/2022] Open
Abstract
Molecular mechanisms underpinning nonalcoholic fatty liver disease (NAFLD) are not well understood. The earliest step of NAFLD is hepatic steatosis, which is one of the main characteristics of aging liver. Here, we present a molecular scenario of age-related liver steatosis. We show that C/EBPα-S193D knockin mice have age-associated epigenetic changes and develop hepatic steatosis at 2 months of age. The underlying mechanism of the hepatic steatosis in old wild-type (WT) mice and in young S193D mice includes increased amounts of tripartite p300-C/EBPα/β complexes that activate promoters of five genes that drive triglyceride synthesis. Knockdown of p300 in old WT mice inhibits hepatic steatosis. Indeed, transgenic mice expressing dominant-negative p300 have fewer C/EBPα/β-p300 complexes and do not develop age-dependent hepatic steatosis. Notably, the p300-C/EBPα/β pathway is activated in the livers of patients with NAFLD. Thus, our results show that p300 and C/EBP proteins are essential participants in hepatic steatosis.
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Affiliation(s)
- Jingling Jin
- Huffington Center on Aging and Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
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Talwar S, Balasubramanian S, Sundaramurthy S, House R, Wilusz CJ, Kuppuswamy D, D'Silva N, Gillespie MB, Hill EG, Palanisamy V. Overexpression of RNA-binding protein CELF1 prevents apoptosis and destabilizes pro-apoptotic mRNAs in oral cancer cells. RNA Biol 2013; 10:277-86. [PMID: 23324604 PMCID: PMC3594286 DOI: 10.4161/rna.23315] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
CELF1 RNA-binding protein, otherwise called CUGBP1, associates and coordinates the degradation of GU-rich element (GRE) containing mRNA’s encoding factors important for cell growth, migration and apoptosis. Although many substrates of CELF1 have been identified, the biological significance of CELF1-mediated mRNA decay remains unclear. As the processes modulated by CELF1 are frequently disrupted in cancer, we investigated the expression and role of CELF1 in oral squamous cancer cells (OSCCs). We determined that CELF1 is reproducibly overexpressed in OSCC tissues and cell lines. Moreover, depletion of CELF1 reduced proliferation and increased apoptosis in OSCCs, but had negligible effect in non-transformed cells. We found that CELF1 associates directly with the 3′UTR of mRNAs encoding the pro-apoptotic factors BAD, BAX and JunD and mediates their rapid decay. Specifically, 3′UTR fragment analysis of JunD revealed that the GRE region is critical for binding with CELF1 and expression of JunD in oral cancer cells. In addition, silencing of CELF1 rendered BAD, BAX and JunD mRNAs stable and increased their protein expression in oral cancer cells. Taken together, these results support a critical role for CELF1 in modulating apoptosis and implicate this RNA-binding protein as a cancer marker and potential therapeutic target.
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Affiliation(s)
- Sudha Talwar
- Department of Craniofacial Biology and Center for Oral Health Research, College of Dental Medicine, Medical University of South Carolina, Charleston, SC, USA
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Jones K, Wei C, Iakova P, Bugiardini E, Schneider-Gold C, Meola G, Woodgett J, Killian J, Timchenko NA, Timchenko LT. GSK3β mediates muscle pathology in myotonic dystrophy. J Clin Invest 2012; 122:4461-72. [PMID: 23160194 DOI: 10.1172/jci64081] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 09/21/2012] [Indexed: 02/01/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a complex neuromuscular disease characterized by skeletal muscle wasting, weakness, and myotonia. DM1 is caused by the accumulation of CUG repeats, which alter the biological activities of RNA-binding proteins, including CUG-binding protein 1 (CUGBP1). CUGBP1 is an important skeletal muscle translational regulator that is activated by cyclin D3-dependent kinase 4 (CDK4). Here we show that mutant CUG repeats suppress Cdk4 signaling by increasing the stability and activity of glycogen synthase kinase 3β (GSK3β). Using a mouse model of DM1 (HSA(LR)), we found that CUG repeats in the 3' untranslated region (UTR) of human skeletal actin increase active GSK3β in skeletal muscle of mice, prior to the development of skeletal muscle weakness. Inhibition of GSK3β in both DM1 cell culture and mouse models corrected cyclin D3 levels and reduced muscle weakness and myotonia in DM1 mice. Our data predict that compounds normalizing GSK3β activity might be beneficial for improvement of muscle function in patients with DM1.
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Affiliation(s)
- Karlie Jones
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA
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Jones K, Timchenko L, Timchenko NA. The role of CUGBP1 in age-dependent changes of liver functions. Ageing Res Rev 2012; 11:442-9. [PMID: 22446383 DOI: 10.1016/j.arr.2012.02.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/09/2012] [Accepted: 02/10/2012] [Indexed: 12/14/2022]
Abstract
Aging liver is characterized by alterations of liver biology and by a reduction of many functions which are important for the maintenance of body homeostasis. The main dysfunctions include appearance of enlarged hepatocytes, impaired liver regeneration after partial hepatectomy (PH), development of hepatic steatosis, reduction of secretion of proteins and alterations in the hepatic sinusoid. RNA binding proteins are involved in the regulation of gene expression in all tissues including regulation of biological processes in the liver. This review is focused on the role of a conserved, multi-functional RNA-binding protein, CUGBP1, in the development of aging phenotype in the liver. CUGBP1 has been identified as a protein which binds to RNA CUG repeats expanded in Myotonic Dystrophy type 1 (DM1). CUGBP1 is highly expressed in the liver and regulates translation of proteins which are critical for maintenance of liver functions. In livers of young mice, CUGBP1 forms complexes with eukaryotic translation initiation factor eIF2 and supports translation of C/EBPβ and HDAC1 proteins, which are involved in liver growth, differentiation and liver cancer. Aging changes several signaling pathways which lead to the elevation of the CUGBP1-eIF2α complex and to an increase of translation of C/EBPβ and HDAC1. These proteins form multi-protein complexes with additional transcription factors and with chromatin remodeling proteins causing epigenetic alterations of gene expression in livers of old mice. It appears that CUGBP1-mediated translational elevation of HDAC1 is one of the key events in the epigenetic changes in livers of old mice, leading to the development of age-associated dysfunctions of the liver. This review will also discuss a possible role of CUGBP1 in liver dysfunction in patients affected with DM1.
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41
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Wang W. Regulatory RNA-binding proteins in senescence. Ageing Res Rev 2012; 11:485-90. [PMID: 22414963 DOI: 10.1016/j.arr.2012.02.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/08/2012] [Accepted: 02/08/2012] [Indexed: 11/18/2022]
Abstract
The expression of senescence-associated genes, which governs the progression and the maintenance of senescence, is regulated at multiple levels. Apart from the transcriptional mechanisms that control cellular senescence, studies over the past decade have revealed that post-transcriptional gene regulation, especially through changes in mRNA turnover and translation, critically influences protein expression patterns in the senescent cell. Among the post-transcriptional regulatory factors, RNA-binding proteins (RBPs) are particularly influential in the establishment of senescence-associated protein profiles. In this review, I discuss the current knowledge of the role of RBPs in cellular senescence and the molecular mechanisms that regulate their function.
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Affiliation(s)
- Wengong Wang
- Department of Biochemistry and Molecular Biology, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, PR China.
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Dey S, Savant S, Teske BF, Hatzoglou M, Calkhoven CF, Wek RC. Transcriptional repression of ATF4 gene by CCAAT/enhancer-binding protein β (C/EBPβ) differentially regulates integrated stress response. J Biol Chem 2012; 287:21936-49. [PMID: 22556424 DOI: 10.1074/jbc.m112.351783] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Different environmental stresses induce the phosphorylation of eIF2 (eIF2∼P), repressing global protein synthesis coincident with preferential translation of ATF4. ATF4 is a transcriptional activator of genes involved in metabolism and nutrient uptake, antioxidation, and regulation of apoptosis. Because ATF4 is a common downstream target that integrates signaling from different eIF2 kinases and their respective stress signals, the eIF2∼P/ATF4 pathway is collectively referred to as the integrated stress response. Although eIF2∼P elicits translational control in response to many different stresses, there are selected stresses, such as exposure to UV irradiation, that do not increase ATF4 expression despite robust eIF2∼P. The rationale for this discordant induction of ATF4 expression and eIF2∼P in response to UV irradiation is that transcription of ATF4 is repressed, and therefore ATF4 mRNA is not available for preferential translation. In this study, we show that C/EBPβ is a transcriptional repressor of ATF4 during UV stress. C/EBPβ binds to critical elements in the ATF4 promoter, resulting in its transcriptional repression. Expression of C/EBPβ increases in response to UV stress, and the liver-enriched inhibitory protein (LIP) isoform of C/EBPβ, but not the liver-enriched activating protein (LAP) version, represses ATF4 transcription. Loss of the liver-enriched inhibitory protein isoform results in increased ATF4 mRNA levels in response to UV irradiation and subsequent recovery of ATF4 translation, leading to enhanced expression of its target genes. Together these results illustrate how eIF2∼P and translational control combined with transcription factors regulated by alternative signaling pathways can direct programs of gene expression that are specifically tailored to each environmental stress.
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Affiliation(s)
- Souvik Dey
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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Beisang D, Rattenbacher B, Vlasova-St Louis IA, Bohjanen PR. Regulation of CUG-binding protein 1 (CUGBP1) binding to target transcripts upon T cell activation. J Biol Chem 2011; 287:950-60. [PMID: 22117072 DOI: 10.1074/jbc.m111.291658] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The RNA-binding protein, CUG-binding protein 1 (CUGBP1), regulates gene expression at the levels of alternative splicing, mRNA degradation, and translation. We used RNA immunoprecipitation followed by microarray analysis to identify the cytoplasmic mRNA targets of CUGBP1 in resting and activated primary human T cells and found that CUGBP1 targets were highly enriched for the presence of GU-rich elements (GREs) in their 3'-untranslated regions. The number of CUGBP1 target transcripts decreased dramatically following T cell activation as a result of activation-dependent phosphorylation of CUGBP1 and decreased ability of CUGBP1 to bind to GRE-containing RNA. A large percentage of CUGBP1 target transcripts exhibited rapid and transient up-regulation, and a smaller percentage exhibited transient down-regulation following T cell activation. Many of the transiently up-regulated CUGBP1 target transcripts encode important regulatory proteins necessary for transition from a quiescent state to a state of cellular activation and proliferation. Overall, our results show that CUGBP1 binding to certain GRE-containing target transcripts decreased following T cell activation through activation-dependent phosphorylation of CUGBP1.
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Affiliation(s)
- Daniel Beisang
- Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis, Minnesota 55455, USA
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44
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Jones K, Jin B, Iakova P, Huichalaf C, Sarkar P, Schneider-Gold C, Schoser B, Meola G, Shyu AB, Timchenko N, Timchenko L. RNA Foci, CUGBP1, and ZNF9 are the primary targets of the mutant CUG and CCUG repeats expanded in myotonic dystrophies type 1 and type 2. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:2475-89. [PMID: 21889481 DOI: 10.1016/j.ajpath.2011.07.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 06/29/2011] [Accepted: 07/11/2011] [Indexed: 01/02/2023]
Abstract
Expansions of noncoding CUG and CCUG repeats in myotonic dystrophies type 1 (DM1) and DM2 cause complex molecular pathology, the features of which include accumulation of RNA aggregates and misregulation of the RNA-binding proteins muscleblind-like 1 (MBNL1) and CUG-binding protein 1 (CUGBP1). CCUG repeats also decrease amounts of the nucleic acid binding protein ZNF9. Using tetracycline (Tet)-regulated monoclonal cell models that express CUG and CCUG repeats, we found that low levels of long CUG and CCUG repeats result in nuclear and cytoplasmic RNA aggregation with a simultaneous increase of CUGBP1 and a reduction of ZNF9. Elevation of CUGBP1 and reduction of ZNF9 were also observed before strong aggregation of the mutant CUG/CCUG repeats. Degradation of CUG and CCUG repeats normalizes ZNF9 and CUGBP1 levels. Comparison of short and long CUG and CCUG RNAs showed that great expression of short repeats form foci and alter CUGBP1 and ZNF9; however, long CUG/CCUG repeats misregulate CUGBP1 and ZNF9 much faster than high levels of the short repeats. These data suggest that correction of DM1 and DM2 might be achieved by complete and efficient degradation of CUG and CCUG repeats or by a simultaneous disruption of CUG/CCUG foci and correction of CUGBP1 and ZNF9.
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Affiliation(s)
- Karlie Jones
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
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Dasgupta T, Ladd AN. The importance of CELF control: molecular and biological roles of the CUG-BP, Elav-like family of RNA-binding proteins. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 3:104-21. [PMID: 22180311 DOI: 10.1002/wrna.107] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
RNA processing is important for generating protein diversity and modulating levels of protein expression. The CUG-BP, Elav-like family (CELF) of RNA-binding proteins regulate several steps of RNA processing in the nucleus and cytoplasm, including pre-mRNA alternative splicing, C to U RNA editing, deadenylation, mRNA decay, and translation. In vivo, CELF proteins have been shown to play roles in gametogenesis and early embryonic development, heart and skeletal muscle function, and neurosynaptic transmission. Dysregulation of CELF-mediated programs has been implicated in the pathogenesis of human diseases affecting the heart, skeletal muscles, and nervous system.
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Affiliation(s)
- Twishasri Dasgupta
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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Hierarchies of transcriptional regulation during liver regeneration. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 97:201-27. [PMID: 21074734 DOI: 10.1016/b978-0-12-385233-5.00007-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The remarkable capacity of the liver to regenerate after severe injury or disease has excited interest for centuries. The goal of harnessing this process in treatment of liver disease, and the appreciation of the parallels between regeneration and tumor development in the liver, remain a major driver for research in this area. Studies of liver regeneration as a model system offer a view of intricate and precisely timed regulatory pathways that drive the process toward completion. Successful regeneration of the liver mass demands a hierarchal and well-controlled balance between proliferative and metabolic functions, which is orchestrated by signaling and regulation of transcription factors. Control and regulation of these cascades of transcriptional activities, necessary for induction, renewal, and cessation of liver growth, are the focus of this chapter.
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Edwards J, Malaurie E, Kondrashov A, Long J, de Moor CH, Searle MS, Emsley J. Sequence determinants for the tandem recognition of UGU and CUG rich RNA elements by the two N--terminal RRMs of CELF1. Nucleic Acids Res 2011; 39:8638-50. [PMID: 21743084 PMCID: PMC3201864 DOI: 10.1093/nar/gkr510] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
CUGBP, Elav-like family member 1 (CELF1) is an RNA binding protein with important roles in the regulation of splicing, mRNA decay and translation. CELF1 contains three RNA recognition motifs (RRMs). We used gel retardation, gel filtration, isothermal titration calorimetry and NMR titration studies to investigate the recognition of RNA by the first two RRMs of CELF1. NMR shows that RRM1 is promiscuous in binding to both UGU and CUG repeat sequences with comparable chemical shift perturbations. In contrast, RRM2 shows greater selectivity for UGUU rather than CUG motifs. A construct (T187) containing both binding domains (RRM1 and RRM2) was systematically studied for interaction with tandem UGU RNA binding sites with different length linker sequences UGU(U)xUGU where x = 1–7. A single U spacer results in interactions only with RRM1, demonstrating both steric constraints in accommodating both RRMs simultaneously at adjacent sites, and also subtle differences in binding affinities between RRMs. However, high affinity co-operative binding (Kd ~ 0.4 µM) is evident for RNA sequences with x = 2–4, but longer spacers (x ≥ 5) lead to a 10-fold reduction in affinity. Our analysis rationalizes the high affinity interaction of T187 with the 11mer GRE consensus regulatory sequence UGUUUGUUUGU and has significant consequences for the prediction of CELF1 binding sites.
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Affiliation(s)
- John Edwards
- School of Chemistry, Centre for Biomolecular Sciences, University Park, Nottingham NG7 2RD, UK
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48
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Salminen A, Ojala J, Kaarniranta K, Haapasalo A, Hiltunen M, Soininen H. Astrocytes in the aging brain express characteristics of senescence-associated secretory phenotype. Eur J Neurosci 2011; 34:3-11. [PMID: 21649759 DOI: 10.1111/j.1460-9568.2011.07738.x] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cellular stress increases progressively with aging in mammalian tissues. Chronic stress triggers several signaling cascades that can induce a condition called cellular senescence. Recent studies have demonstrated that senescent cells express a senescence-associated secretory phenotype (SASP). Emerging evidence indicates that the number of cells expressing biomarkers of cellular senescence increases in tissues with aging, which implies that cellular senescence is an important player in organismal aging. In the brain, the aging process is associated with degenerative changes, e.g. synaptic loss and white matter atrophy, which lead to progressive cognitive impairment. There is substantial evidence for the presence of oxidative, proteotoxic and metabolic stresses in aging brain. A low-level, chronic inflammatory process is also present in brain during aging. Astrocytes demonstrate age-related changes that resemble those of the SASP: (i) increased level of intermediate glial fibrillary acidic protein and vimentin filaments, (ii) increased expression of several cytokines and (iii) increased accumulation of proteotoxic aggregates. In addition, in vitro stress evokes a typical senescent phenotype in cultured astrocytes and, moreover, isolated astrocytes from aged brain display the proinflammatory phenotype. All of these observations indicate that astrocytes are capable of triggering the SASP and the astrocytes in aging brain display typical characteristics of cellular senescence. Bearing in mind the many functions of astrocytes, it is evident that the age-related senescence of astrocytes enhances the decline in functional capacity of the brain. We will review the astroglial changes occurring during aging and emphasize that senescent astrocytes can have an important role in age-related neuroinflammation and neuronal degeneration.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
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49
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Iakova P, Timchenko L, Timchenko NA. Intracellular signaling and hepatocellular carcinoma. Semin Cancer Biol 2010; 21:28-34. [PMID: 20850540 DOI: 10.1016/j.semcancer.2010.09.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 09/05/2010] [Accepted: 09/09/2010] [Indexed: 12/13/2022]
Abstract
Liver cancer is the fifth most common cancer and the third most common cause of cancer related death in the world. The recent development of new techniques for the investigations of global change in the gene expression, signaling pathways and wide genome binding has provided novel information for the mechanisms underlying liver cancer progression. Although these studies identified gene expression signatures in hepatocellular carcinoma, the early steps of the development of hepatocellular carcinomas (HCC) are not well understood. The development of HCC is a multistep process which includes the progressive alterations of gene expression leading to the increased proliferation and to liver cancer. This review summarizes recent progress in the identification of the key steps of the development of HCC with the focus on early events of carcinogenesis and on the role of translational and epigenetic alterations in the development of HCC. Quiescent stage of the liver is supported by several tumor suppressor proteins including p53, Rb and C/EBPα. Studies with chemical models of liver carcinogenesis and with human HCC have shown that the elevation of gankyrin is responsible for the elimination of these three proteins at early steps of carcinogenesis. Later stages of progression of the liver cancer are associated with alterations in many signaling pathways including translation which leads to epigenetic silencing/activation of many genes. Particularly, recent reports suggest a critical role of histone deacetylase 1, HDAC1, in the development of HCC through the interactions with transcription factors such as C/EBP family proteins.
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Affiliation(s)
- Polina Iakova
- Department of Pathology and Immunology and Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States
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50
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Horb LD, Horb ME. BrunoL1 regulates endoderm proliferation through translational enhancement of cyclin A2 mRNA. Dev Biol 2010; 345:156-69. [PMID: 20633547 DOI: 10.1016/j.ydbio.2010.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 06/12/2010] [Accepted: 07/02/2010] [Indexed: 10/19/2022]
Abstract
Developmental control of proliferation relies on tight regulation of protein expression. Although this has been well studied in early embryogenesis, how the cell cycle is regulated during organogenesis is not well understood. Bruno-Like RNA binding proteins bind to consensus sequences in the 3'UTR of specific mRNAs and repress protein translation, but much of this functional information is derived from studies on mainly two members, Drosophila Bruno and vertebrate BrunoL2 (CUGBP1). There are however, six vertebrate and three Drosophila Bruno family members, but less is known about these other family members, and none have been shown to function in the endoderm. We recently identified BrunoL1 as a dorsal pancreas enriched gene, and in this paper we define BrunoL1 function in Xenopus endoderm development. We find that, in contrast to other Bruno-Like proteins, BrunoL1 acts to enhance rather than repress translation. We demonstrate that BrunoL1 regulates proliferation of endoderm cells through translational control of cyclin A2 mRNA. Specifically BrunoL1 enhanced translation of cyclin A2 through binding consensus Bruno Response Elements (BREs) in its 3'UTR. We compared the ability of other Bruno-Like proteins, both vertebrate and invertebrate, to stimulate translation via the cyclin A2 3'UTR and found that only Drosophila Bru-3 had similar activity. In addition, we also found that both BrunoL1 and Bru-3 enhanced translation of mRNAs containing the 3'UTRs of Drosophila oskar or cyclin A, which have been well characterized to mediate repression. Lastly, we show that it is the Linker region of BrunoL1 that is both necessary and sufficient for this activity. These results are the first example of BRE-dependent translational enhancement and are the first demonstration in vertebrates of Bruno-Like proteins regulating translation through BREs.
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Affiliation(s)
- Lori Dawn Horb
- Laboratory of Molecular Organogenesis, Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada
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