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Wang H, Dong Y, Xu Q, Wang M, Li S, Ji Y. MicroRNA750-3p Targets Processing of Precursor 7 to Suppress Rice Black-Streaked Dwarf Virus Propagation in Vector Laodelphax striatellus. Viruses 2024; 16:97. [PMID: 38257797 PMCID: PMC10820416 DOI: 10.3390/v16010097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/27/2023] [Accepted: 01/04/2024] [Indexed: 01/24/2024] Open
Abstract
MicroRNAs (miRNAs) are non-coding RNAs, which, as members of the RNA interference pathway, play a pivotal role in antiviral infection. Almost 80% of plant viruses are transmitted by insect vectors; however, little is known about the interaction of the miRNAs of insect vectors with plant viruses. Here, we took rice black-streaked dwarf virus (RBSDV), a devastating virus to rice production in eastern Asia, and the small brown planthopper, (SBPH, Laodelphax striatellus) as a model to investigate the role of microRNA750-3p (miR750-3p) in regulating viral transmission. Our results showed that Ls-miR750-3p was downregulated in RBSDV-infected SBPH and predominately expressed in the midgut of SBPH. Injection with miR750-3p agomir significantly reduced viral accumulation, and the injection with the miR750-3p inhibitor, antagomir-750-3p, dramatically promoted the viral accumulation in SBPH, as detected using RT-qPCR and Western blotting. The processing of precursor 7 (POP7), a subunit of RNase P and RNase MRP, was screened, identified, and verified using a dual luciferase reporter assay as one target of miR750-3p. Knockdown of POP7 notably increased RBSDV viral propagation in SBPH and then increased the viral transmission rate by SBPH. Taken together, our data indicate that miR750-3p targets POP7 to suppress RBSDV infection in its insect vector. These results enriched the role of POP7 in modulating virus infection in host insects and shared new insight into the function of miRNAs in plant virus and insect vector interaction.
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Affiliation(s)
| | | | | | | | | | - Yinghua Ji
- Institute of Plant Protection, Key Laboratory of Food Quality and Safety of Jiangsu Province, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
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2
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Huang Y, Zheng Y, Yao L, Qiao F, Hou Y, Hu X, Li D, Shao Z. RNA binding protein POP7 regulates ILF3 mRNA stability and expression to promote breast cancer progression. Cancer Sci 2022; 113:3801-3813. [PMID: 35579257 DOI: 10.1111/cas.15430] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 05/07/2022] [Accepted: 05/12/2022] [Indexed: 11/29/2022] Open
Abstract
RNA Binding Proteins(RBPs)play pivotal roles in breast cancer (BC) development. As a RBP, Processing of precursor 7 (POP7) is one of the subunits of RNase P and RNase MRP, however, its exact function and mechanism in BC remain unknown. Here, we showed that expression of POP7 was frequently increased in breast cancer cells and in primary breast tumors. Up-regulated POP7 significantly promoted BC cell proliferation in vitro and primary tumor growth in vivo. POP7 also increased cell migration, invasion in vitro and lung metastasis in vivo. Through RNA-immunoprecipitation coupled with sequencing (RIP-seq), we found that POP7 bound preferentially to intron regions and POP7-binding peak associated genes were mainly enriched in cancer-related pathways. Further, POP7 regulated Interleukin Enhancer Binding Factor 3 (ILF3) expression through influencing its mRNA stability. Knockdown of ILF3 significantly impaired the increased malignant potential of POP7 over-expressing cells, suggesting that POP7 enhances BC progression through regulating ILF3 expression. Collectively, our findings provide the first evidence for the important role of POP7 and its regulation of ILF3 in promoting breast cancer progression.
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Affiliation(s)
- Yanni Huang
- Department of Breast Surgery, Key Laboratory of Breast Cancer in Shanghai, Fudan University, Shanghai Cancer Center, Fudan University, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yizi Zheng
- Department of Breast Surgery, Key Laboratory of Breast Cancer in Shanghai, Fudan University, Shanghai Cancer Center, Fudan University, Shanghai, China.,Department of Thyroid and Breast Surgery, Shenzhen Second People's Hospital/First Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
| | - Ling Yao
- Department of Breast Surgery, Key Laboratory of Breast Cancer in Shanghai, Fudan University, Shanghai Cancer Center, Fudan University, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Feng Qiao
- Precision Cancer Medicine Center, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Yifeng Hou
- Department of Breast Surgery, Key Laboratory of Breast Cancer in Shanghai, Fudan University, Shanghai Cancer Center, Fudan University, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xin Hu
- Department of Breast Surgery, Key Laboratory of Breast Cancer in Shanghai, Fudan University, Shanghai Cancer Center, Fudan University, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Precision Cancer Medicine Center, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Daqiang Li
- Department of Breast Surgery, Key Laboratory of Breast Cancer in Shanghai, Fudan University, Shanghai Cancer Center, Fudan University, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Zhiming Shao
- Department of Breast Surgery, Key Laboratory of Breast Cancer in Shanghai, Fudan University, Shanghai Cancer Center, Fudan University, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Precision Cancer Medicine Center, Fudan University Shanghai Cancer Center, Shanghai, China
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3
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Shaukat AN, Kaliatsi EG, Skeparnias I, Stathopoulos C. The Dynamic Network of RNP RNase P Subunits. Int J Mol Sci 2021; 22:ijms221910307. [PMID: 34638646 PMCID: PMC8509007 DOI: 10.3390/ijms221910307] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 11/17/2022] Open
Abstract
Ribonuclease P (RNase P) is an important ribonucleoprotein (RNP), responsible for the maturation of the 5′ end of precursor tRNAs (pre-tRNAs). In all organisms, the cleavage activity of a single phosphodiester bond adjacent to the first nucleotide of the acceptor stem is indispensable for cell viability and lies within an essential catalytic RNA subunit. Although RNase P is a ribozyme, its kinetic efficiency in vivo, as well as its structural variability and complexity throughout evolution, requires the presence of one protein subunit in bacteria to several protein partners in archaea and eukaryotes. Moreover, the existence of protein-only RNase P (PRORP) enzymes in several organisms and organelles suggests a more complex evolutionary timeline than previously thought. Recent detailed structures of bacterial, archaeal, human and mitochondrial RNase P complexes suggest that, although apparently dissimilar enzymes, they all recognize pre-tRNAs through conserved interactions. Interestingly, individual protein subunits of the human nuclear and mitochondrial holoenzymes have additional functions and contribute to a dynamic network of elaborate interactions and cellular processes. Herein, we summarize the role of each RNase P subunit with a focus on the human nuclear RNP and its putative role in flawless gene expression in light of recent structural studies.
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4
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Walsh MB, Janzen E, Wingrove E, Hosseinibarkooie S, Muela NR, Davidow L, Dimitriadi M, Norabuena EM, Rubin LL, Wirth B, Hart AC. Genetic modifiers ameliorate endocytic and neuromuscular defects in a model of spinal muscular atrophy. BMC Biol 2020; 18:127. [PMID: 32938453 PMCID: PMC7495824 DOI: 10.1186/s12915-020-00845-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/11/2020] [Indexed: 12/31/2022] Open
Abstract
Background Understanding the genetic modifiers of neurodegenerative diseases can provide insight into the mechanisms underlying these disorders. Here, we examine the relationship between the motor neuron disease spinal muscular atrophy (SMA), which is caused by reduced levels of the survival of motor neuron (SMN) protein, and the actin-bundling protein Plastin 3 (PLS3). Increased PLS3 levels suppress symptoms in a subset of SMA patients and ameliorate defects in SMA disease models, but the functional connection between PLS3 and SMN is poorly understood. Results We provide immunohistochemical and biochemical evidence for large protein complexes localized in vertebrate motor neuron processes that contain PLS3, SMN, and members of the hnRNP F/H family of proteins. Using a Caenorhabditis elegans (C. elegans) SMA model, we determine that overexpression of PLS3 or loss of the C. elegans hnRNP F/H ortholog SYM-2 enhances endocytic function and ameliorates neuromuscular defects caused by decreased SMN-1 levels. Furthermore, either increasing PLS3 or decreasing SYM-2 levels suppresses defects in a C. elegans ALS model. Conclusions We propose that hnRNP F/H act in the same protein complex as PLS3 and SMN and that the function of this complex is critical for endocytic pathways, suggesting that hnRNP F/H proteins could be potential targets for therapy development.
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Affiliation(s)
- Melissa B Walsh
- Department of Neuroscience, Brown University, 185 Meeting Street, Mailbox GL-N, Providence, RI, 02912, USA
| | - Eva Janzen
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute of Genetics, and Center for Rare Disorders, University of Cologne, Cologne, Germany
| | - Emily Wingrove
- Department of Neuroscience, Brown University, 185 Meeting Street, Mailbox GL-N, Providence, RI, 02912, USA
| | - Seyyedmohsen Hosseinibarkooie
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute of Genetics, and Center for Rare Disorders, University of Cologne, Cologne, Germany
| | - Natalia Rodriguez Muela
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Lance Davidow
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Maria Dimitriadi
- Department of Biological and Environmental Sciences, University of Hertfordshire, Hertfordshire, UK
| | - Erika M Norabuena
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Lee L Rubin
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute of Genetics, and Center for Rare Disorders, University of Cologne, Cologne, Germany
| | - Anne C Hart
- Department of Neuroscience, Brown University, 185 Meeting Street, Mailbox GL-N, Providence, RI, 02912, USA.
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5
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D'Ambrosi N, Cozzolino M, Carrì MT. Neuroinflammation in Amyotrophic Lateral Sclerosis: Role of Redox (dys)Regulation. Antioxid Redox Signal 2018; 29:15-36. [PMID: 28895473 DOI: 10.1089/ars.2017.7271] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Amyotrophic lateral sclerosis (ALS) is due to degeneration of upper and lower motor neurons in the anterior horn of the spinal cord and in the motor cortex. Mechanisms leading to motor neuron death are complex and currently the disease is untreatable. Recent Advances: Work in genetic models of ALS indicates that an imbalance in the cross talk that physiologically exists between motor neurons and the surrounding cells is eventually detrimental to motor neurons. In particular, the cascade of events collectively known as neuroinflammation and mainly characterized by a reactive phenotype of astrocytes and microglia, moderate infiltration of peripheral immune cells, and elevated levels of inflammatory mediators has been consistently observed in motor regions of the central nervous system (CNS) in sporadic and familial ALS, constituting a hallmark of the disease. Resident glial cells and infiltrated immune cells are considered among the major producers of reactive species of oxygen and nitrogen in pathological conditions of the CNS, including motor neuron diseases. CRITICAL ISSUES The timing and exact role of oxidative stress-mediated neuroinflammation and damage to motor neurons in ALS are still not fully elucidated. FUTURE DIRECTIONS It is clear that a major challenge in the next future will be to envisage effective strategies to modulate the neuroinflammatory response in the symptomatic stage of disease, to prevent progression of neurodegeneration through the propagation of oxidative damage. Antioxid. Redox Signal. 29, 15-36.
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Affiliation(s)
- Nadia D'Ambrosi
- 1 Department of Biology, University of Rome Tor Vergata , Rome, Italy
| | - Mauro Cozzolino
- 2 Institute of Translational Pharmacology , CNR, Rome, Italy
| | - Maria Teresa Carrì
- 1 Department of Biology, University of Rome Tor Vergata , Rome, Italy .,3 Fondazione Santa Lucia , IRCCS, Rome, Italy
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6
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Poblete-Durán N, Prades-Pérez Y, Vera-Otarola J, Soto-Rifo R, Valiente-Echeverría F. Who Regulates Whom? An Overview of RNA Granules and Viral Infections. Viruses 2016; 8:v8070180. [PMID: 27367717 PMCID: PMC4974515 DOI: 10.3390/v8070180] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/10/2016] [Accepted: 06/21/2016] [Indexed: 12/22/2022] Open
Abstract
After viral infection, host cells respond by mounting an anti-viral stress response in order to create a hostile atmosphere for viral replication, leading to the shut-off of mRNA translation (protein synthesis) and the assembly of RNA granules. Two of these RNA granules have been well characterized in yeast and mammalian cells, stress granules (SGs), which are translationally silent sites of RNA triage and processing bodies (PBs), which are involved in mRNA degradation. This review discusses the role of these RNA granules in the evasion of anti-viral stress responses through virus-induced remodeling of cellular ribonucleoproteins (RNPs).
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Affiliation(s)
- Natalia Poblete-Durán
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
| | - Yara Prades-Pérez
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
| | - Jorge Vera-Otarola
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago 8330024, Chile.
| | - Ricardo Soto-Rifo
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
| | - Fernando Valiente-Echeverría
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
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7
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Onomoto K, Yoneyama M, Fung G, Kato H, Fujita T. Antiviral innate immunity and stress granule responses. Trends Immunol 2014; 35:420-8. [PMID: 25153707 PMCID: PMC7185371 DOI: 10.1016/j.it.2014.07.006] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 07/16/2014] [Accepted: 07/16/2014] [Indexed: 12/13/2022]
Abstract
Viral infection triggers the activation of antiviral innate immune responses in mammalian cells. Viral RNA in the cytoplasm activates signaling pathways that result in the production of interferons (IFNs) and IFN-stimulated genes. Some viral infections have been shown to induce cytoplasmic granular aggregates similar to the dynamic ribonucleoprotein aggregates termed stress granules (SGs), suggesting that these viruses may utilize this stress response for their own benefit. By contrast, some viruses actively inhibit SG formation, suggesting an antiviral function for these structures. We review here the relationship between different viral infections and SG formation. We examine the evidence for antiviral functions for SGs and highlight important areas of inquiry towards understanding cellular stress responses to viral infection.
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Affiliation(s)
- Koji Onomoto
- Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, Chiba 260-8673, Japan
| | - Mitsutoshi Yoneyama
- Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, Chiba 260-8673, Japan
| | - Gabriel Fung
- University of British Columbia (UBC) James Hogg Research Center, Providence Heart and Lung Institute, St. Paul's Hospital and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Hiroki Kato
- Laboratory of Molecular Genetics, Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan; Laboratory of Molecular Cell Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8507, Japan
| | - Takashi Fujita
- Laboratory of Molecular Genetics, Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan; Laboratory of Molecular Cell Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8507, Japan.
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8
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Brose RD, Shin G, McGuinness MC, Schneidereith T, Purvis S, Dong GX, Keefer J, Spencer F, Smith KD. Activation of the stress proteome as a mechanism for small molecule therapeutics. Hum Mol Genet 2012; 21:4237-52. [PMID: 22752410 DOI: 10.1093/hmg/dds247] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Various small molecule pharmacologic agents with different known functions produce similar outcomes in diverse Mendelian and complex disorders, suggesting that they may induce common cellular effects. These molecules include histone deacetylase inhibitors, 4-phenylbutyrate (4PBA) and trichostatin A, and two small molecules without direct histone deacetylase inhibitor activity, hydroxyurea (HU) and sulforaphane. In some cases, the therapeutic effects of histone deacetylase inhibitors have been attributed to an increase in expression of genes related to the disease-causing gene. However, here we show that the pharmacological induction of mitochondrial biogenesis was necessary for the potentially therapeutic effects of 4PBA or HU in two distinct disease models, X-linked adrenoleukodystrophy and sickle cell disease. We hypothesized that a common cellular response to these four molecules is induction of mitochondrial biogenesis and peroxisome proliferation and activation of the stress proteome, or adaptive cell survival response. Treatment of human fibroblasts with these four agents induced mitochondrial and peroxisomal biogenesis as monitored by flow cytometry, immunofluorescence and/or western analyses. In treated normal human fibroblasts, all four agents induced the adaptive cell survival response: heat shock, unfolded protein, autophagic and antioxidant responses and the c-jun N-terminal kinase pathway, at the transcriptional and translational levels. Thus, activation of the evolutionarily conserved stress proteome and mitochondrial biogenesis may be a common cellular response to such small molecule therapy and a common basis of therapeutic action in various diseases. Modulation of this novel therapeutic target could broaden the range of treatable diseases without directly targeting the causative genetic abnormalities.
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Affiliation(s)
- Rebecca Deering Brose
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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9
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Valiente-Echeverría F, Melnychuk L, Mouland AJ. Viral modulation of stress granules. Virus Res 2012; 169:430-7. [PMID: 22705970 PMCID: PMC7114395 DOI: 10.1016/j.virusres.2012.06.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 06/01/2012] [Accepted: 06/04/2012] [Indexed: 12/14/2022]
Abstract
Following viral infection, the host responds by mounting a robust anti-viral response with the aim of creating an unfavorable environment for viral replication. As a countermeasure, viruses have elaborated mechanisms to subvert the host response in order to maintain viral protein synthesis and production. In the last decade, several reports have shown that viruses modulate the assembly of stress granules (SGs), which are translationally silent ribonucleoproteins (RNPs) and sites of RNA triage. This review discusses recent advances in our understanding of the interactions between viruses and the host response and how virus-induced modulations in SG abundance play fundamental roles in dictating the success of viral replication.
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Affiliation(s)
- Fernando Valiente-Echeverría
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
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10
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Zhou J, Zheng X, Shen H. Targeting RNA-splicing for SMA treatment. Mol Cells 2012; 33:223-8. [PMID: 22382684 PMCID: PMC3887702 DOI: 10.1007/s10059-012-0005-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 02/15/2012] [Accepted: 02/15/2012] [Indexed: 10/28/2022] Open
Abstract
The central dogma of DNA-RNA-protein was established more than 40 years ago. However, important biological processes have been identified since the central dogma was developed. For example, methylation is important in the regulation of transcription. In contrast, proteins, are more complex due to modifications such as phosphorylation, glycosylation, ubiquitination, or cleavage. RNA is the mediator between DNA and protein, but it can also be modulated at several levels. Among the most profound discoveries of RNA regulation is RNA splicing. It has been estimated that 80% of pre-mRNA undergo alternative splicing, which exponentially increases biological information flow in cellular processes. However, an increased number of regulated steps inevitably accompanies an increased number of errors. Abnormal splicing is often found in cells, resulting in protein dysfunction that causes disease. Splicing of the survival motor neuron (SMN) gene has been extensively studied during the last two decades. Accumulating knowledge on SMN splicing has led to speculation and search for spinal muscular atrophy (SMA) treatment by stimulating the inclusion of exon 7 into SMN mRNA. This mini-review summaries the latest progress on SMN splicing research as a potential treatment for SMA disease.
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Affiliation(s)
| | - Xuexiu Zheng
- School of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
| | - Haihong Shen
- School of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
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11
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Fallini C, Bassell GJ, Rossoll W. Spinal muscular atrophy: the role of SMN in axonal mRNA regulation. Brain Res 2012; 1462:81-92. [PMID: 22330725 DOI: 10.1016/j.brainres.2012.01.044] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2011] [Accepted: 01/19/2012] [Indexed: 01/15/2023]
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by homozygous mutations or deletions in the survival of motor neuron (SMN1) gene, encoding the ubiquitously expressed SMN protein. SMN associates with different proteins (Gemins 2-8, Unrip) to form a multimeric complex involved in the assembly of small nuclear ribonucleoprotein complexes (snRNPs). Since this activity is essential for the survival of all cell types, it still remains unclear why motor neurons are selectively vulnerable to low levels of SMN protein. Aside from its housekeeping role in the assembly of snRNPs, additional functions of SMN have been proposed. The well-documented localization of SMN in axonal transport granules and its interaction with numerous mRNA-binding proteins not involved in splicing regulation suggest a role in axonal RNA metabolism. This review will focus on the neuropathological and experimental evidence supporting a role for SMN in regulating the assembly, localization, or stability of axonal messenger ribonucleoprotein complexes (mRNPs). Furthermore, how defects in this non-canonical SMN function may contribute to the motor neuron pathology observed in SMA will be discussed. This article is part of a Special Issue entitled RNA-Binding Proteins.
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Affiliation(s)
- Claudia Fallini
- Department of Cell Biology, School of Medicine, Emory University School of Medicine, Atlanta 30322, USA
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12
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Buckingham M, Liu JL. U bodies respond to nutrient stress in Drosophila. Exp Cell Res 2011; 317:2835-44. [DOI: 10.1016/j.yexcr.2011.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 09/01/2011] [Accepted: 09/04/2011] [Indexed: 10/17/2022]
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13
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Zou T, Yang X, Pan D, Huang J, Sahin M, Zhou J. SMN deficiency reduces cellular ability to form stress granules, sensitizing cells to stress. Cell Mol Neurobiol 2011; 31:541-50. [PMID: 21234798 PMCID: PMC11498399 DOI: 10.1007/s10571-011-9647-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 01/04/2011] [Indexed: 10/18/2022]
Abstract
Spinal Muscular Atrophy (SMA) is a neurodegenerative disease that is caused by deletion of the SMN (Survival of Motor Neuron) gene. The SMN protein is essential for cell survival and co-localized with TIA-1/R and G3BP, two characteristic markers of stress granules (SGs). To further study the SMN function in stress granules and in response to stress, we generated stable cell lines with SMN knockdown. Our data indicate that suppression of SMN drastically reduces cellular ability to form stress granules in response to stress treatment. In addition, we show that SMN deficiency sensitizes cells to sodium arsenite and H(2)O(2), two well-known stress inducers, leading to cell death at a much lower concentration of inducers in SMN knockdown cells than in control cells. Interestingly, the cell death is correlated with formation of stress granules, suggesting that involvement of SMN in formation of stress granules may play an important role in cell survival. Furthermore, rescue of SGs formation by overexpression of G3BP can reverse the defective formation of stress granules and results in partial abrogation of cell death against SMN deficiency. We deduce that modulation of stress response may be useful for potential SMN treatment.
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Affiliation(s)
- Tie Zou
- Department of Medicine, Program in Neuroscience, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605 USA
| | - Xianming Yang
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19th Qixiu Road, Nantong, JiangSu 226007 People’s Republic of China
| | - Danmin Pan
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19th Qixiu Road, Nantong, JiangSu 226007 People’s Republic of China
| | - Jia Huang
- Department of Neurology, Children’s Hospital, Boston, MA 02115 USA
| | - Mustafa Sahin
- Department of Neurology, Children’s Hospital, Boston, MA 02115 USA
| | - Jianhua Zhou
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19th Qixiu Road, Nantong, JiangSu 226007 People’s Republic of China
- Department of Medicine, Program in Neuroscience, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605 USA
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14
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Coady TH, Lorson CL. SMN in spinal muscular atrophy and snRNP biogenesis. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:546-64. [PMID: 21957043 DOI: 10.1002/wrna.76] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ribonucleoprotein (RNP) complexes function in nearly every facet of cellular activity. The spliceosome is an essential RNP that accurately identifies introns and catalytically removes the intervening sequences, providing exquisite control of spatial, temporal, and developmental gene expressions. U-snRNPs are the building blocks for the spliceosome. A significant amount of insight into the molecular assembly of these essential particles has recently come from a seemingly unexpected area of research: neurodegeneration. Survival motor neuron (SMN) performs an essential role in the maturation of snRNPs, while the homozygous loss of SMN1 results in the development of spinal muscular atrophy (SMA), a devastating neurodegenerative disease. In this review, the function of SMN is examined within the context of snRNP biogenesis and evidence is examined which suggests that the SMN functional defects in snRNP biogenesis may account for the motor neuron pathology observed in SMA.
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Affiliation(s)
- Tristan H Coady
- Department of Veterinary Pathobiology, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
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15
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Thomas MG, Loschi M, Desbats MA, Boccaccio GL. RNA granules: the good, the bad and the ugly. Cell Signal 2011; 23:324-34. [PMID: 20813183 PMCID: PMC3001194 DOI: 10.1016/j.cellsig.2010.08.011] [Citation(s) in RCA: 204] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 08/20/2010] [Indexed: 12/13/2022]
Abstract
Processing bodies (PBs) and Stress Granules (SGs) are the founding members of a new class of RNA granules, known as mRNA silencing foci, as they harbour transcripts circumstantially excluded from the translationally active pool. PBs and SGs are able to release mRNAs thus allowing their translation. PBs are constitutive, but respond to stimuli that affect mRNA translation and decay, whereas SGs are specifically induced upon cellular stress, which triggers a global translational silencing by several pathways, including phosphorylation of the key translation initiation factor eIF2alpha, and tRNA cleavage among others. PBs and SGs with different compositions may coexist in a single cell. These macromolecular aggregates are highly conserved through evolution, from unicellular organisms to vertebrate neurons. Their dynamics is regulated by several signaling pathways, and depends on microfilaments and microtubules, and the cognate molecular motors myosin, dynein, and kinesin. SGs share features with aggresomes and related aggregates of unfolded proteins frequently present in neurodegenerative diseases, and may play a role in the pathology. Virus infections may induce or impair SG formation. Besides being important for mRNA regulation upon stress, SGs modulate the signaling balancing apoptosis and cell survival. Finally, the formation of Nuclear Stress Bodies (nSBs), which share components with SGs, and the assembly of additional cytosolic aggregates containing RNA -the UV granules and the Ire1 foci-, all of them induced by specific cell damage factors, contribute to cell survival.
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Key Words
- atxn2, ataxin-2
- bicd, bicaudal d
- cbp, creb binding protein
- cpeb, cytoplasmic polyadenylation element binding protein
- dhc, dynein heavy chain
- dic, dynein intermediate chain
- fak, focal adhesion kinase
- fus/tls/hnrnp p2, fused in sarcoma
- g3bp, ras-gap sh3 domain binding protein
- gcn2, general control nonderepressible-2
- grb7, growth factor receptor-bound protein 7
- hap, hnrnp a1 interacting protein
- hdac6, histone deacetylase 6
- hri, heme-regulated inhibitor
- hsf, heat shock transcription factor
- khc, kinesin heavy chain
- klc, kinesin light chain
- mln51, metastatic lymph node 51
- nmd, nonsense mediated decay
- nsbs, nuclear stress bodies
- ogfod1, 2–14 oxoglutarate and fe(ii)-dependent oxygenase domain containing 1
- pb, processing body
- perk, pancreatic endoplasmic reticulum eif2alpha kinase
- pkr/eif2ak2, double stranded rna-dependent protein kinase
- pp1, protein phosphatase 1
- prp, prion protein
- rbp, rna binding protein
- rnp, ribonucleoparticle
- sam68, src associated in mitosis 68 kda
- member of star, signal transducer and activator of rna
- sca, spinocerebellar ataxia
- sg, stress granule
- sma, spinal muscular atrophy
- fmrp, fragile x mental retardation protein
- smn, survival of motor neuron
- tdp43, tar dna-binding protein 43
- traf2, tnf receptor associated factor 2
- uvgs, uv rna granules
- processing body
- stress granule
- kinesin
- dynein
- bicaudal d
- aggresome
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Affiliation(s)
- María Gabriela Thomas
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
| | - Mariela Loschi
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
| | - María Andrea Desbats
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
| | - Graciela Lidia Boccaccio
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
- University of Buenos Aires
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16
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Abstract
Motor neurons are large, highly polarised cells with very long axons and a requirement for precise spatial and temporal gene expression. Neurodegenerative disorders characterised by selective motor neuron vulnerability include various forms of amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). A rapid expansion in knowledge on the pathophysiology of motor neuron degeneration has occurred in recent years, largely through the identification of genes leading to familial forms of ALS and SMA. The major emerging theme is that motor neuron degeneration can result from mutation in genes that encode factors important for ribonucleoprotein biogenesis and RNA processing, including splicing regulation, transcript stabilisation, translational repression and localisation of mRNA. Complete understanding of how these pathways interact and elucidation of specialised mechanisms for mRNA targeting and processing in motor neurons are likely to produce new targets for therapy in ALS and related disorders.
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17
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Lai LB, Vioque A, Kirsebom LA, Gopalan V. Unexpected diversity of RNase P, an ancient tRNA processing enzyme: challenges and prospects. FEBS Lett 2009; 584:287-96. [PMID: 19931535 DOI: 10.1016/j.febslet.2009.11.048] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 11/09/2009] [Accepted: 11/13/2009] [Indexed: 12/16/2022]
Abstract
For an enzyme functioning predominantly in a seemingly housekeeping role of 5' tRNA maturation, RNase P displays a remarkable diversity in subunit make-up across the three domains of life. Despite the protein complexity of this ribonucleoprotein enzyme increasing dramatically from bacteria to eukarya, the catalytic function rests with the RNA subunit during evolution. However, the recent demonstration of a protein-only human mitochondrial RNase P has added further intrigue to the compositional variability of this enzyme. In this review, we discuss some possible reasons underlying the structural diversity of the active sites, and use them as thematic bases for elaborating new directions to understand how functional variations might have contributed to the complex evolution of RNase P.
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Affiliation(s)
- Lien B Lai
- Department of Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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18
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Kedersha N, Anderson P. Regulation of translation by stress granules and processing bodies. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 90:155-85. [PMID: 20374741 PMCID: PMC7102815 DOI: 10.1016/s1877-1173(09)90004-7] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Stress necessitates rapid reprogramming of translation in order to facilitate an adaptive response and promote survival. Cytoplasmic stress granules (SGs) and processing bodies (PBs) are dynamic structures that form in response to stress-induced translational arrest. PBs are linked to mRNA silencing and decay, while SGs are more closely linked to translation and the sorting of specific mRNAs for different fates. While they share some components and can interact physically, SGs and PBs are regulated independently, house separate functions, and contain unique markers. SG formation is associated with numerous disease states, and the expanding list of SG-associated proteins integrates SG formation with other processes such as transcription, splicing, and survival. Growing evidence suggests that SG assembly is initiated by translational arrest, and mediates cross talk with many other signaling pathways.
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Affiliation(s)
- Nancy Kedersha
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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19
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Rossoll W, Bassell GJ. Spinal muscular atrophy and a model for survival of motor neuron protein function in axonal ribonucleoprotein complexes. Results Probl Cell Differ 2009; 48:289-326. [PMID: 19343312 PMCID: PMC3718852 DOI: 10.1007/400_2009_4] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease that results from loss of function of the SMN1 gene, encoding the ubiquitously expressed survival of motor neuron (SMN) protein, a protein best known for its housekeeping role in the SMN-Gemin multiprotein complex involved in spliceosomal small nuclear ribonucleoprotein (snRNP) assembly. However, numerous studies reveal that SMN has many interaction partners, including mRNA binding proteins and actin regulators, suggesting its diverse role as a molecular chaperone involved in mRNA metabolism. This review focuses on studies suggesting an important role of SMN in regulating the assembly, localization, or stability of axonal messenger ribonucleoprotein (mRNP) complexes. Various animal models for SMA are discussed, and phenotypes described that indicate a predominant function for SMN in neuronal development and synapse formation. These models have begun to be used to test different therapeutic strategies that have the potential to restore SMN function. Further work to elucidate SMN mechanisms within motor neurons and other cell types involved in neuromuscular circuitry hold promise for the potential treatment of SMA.
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Affiliation(s)
- Wilfried Rossoll
- Departments of Cell Biology and Neurology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA 30322, USA.
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20
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Rotavirus infection induces the phosphorylation of eIF2alpha but prevents the formation of stress granules. J Virol 2007; 82:1496-504. [PMID: 18032499 DOI: 10.1128/jvi.01779-07] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Early during the infection process, rotavirus causes the shutoff of cell protein synthesis, with the nonstructural viral protein NSP3 playing a vital role in the phenomenon. In this work, we have found that the translation initiation factor 2alpha (eIF2alpha) in infected cells becomes phosphorylated early after virus infection and remains in this state throughout the virus replication cycle, leading to a further inhibition of cell protein synthesis. Under these restrictive conditions, however, the viral proteins and some cellular proteins are efficiently translated. The phosphorylation of eIF2alpha was shown to depend on the synthesis of three viral proteins, VP2, NSP2, and NSP5, since in cells in which the expression of any of these three proteins was knocked down by RNA interference, the translation factor was not phosphorylated. The modification of this factor is, however, not needed for the replication of the virus, since mutant cells that produce a nonphosphorylatable eIF2alpha sustained virus replication as efficiently as wild-type cells. In uninfected cells, the phosphorylation of eIF2alpha induces the formation of stress granules, aggregates of stalled translation complexes that prevent the translation of mRNAs. In rotavirus-infected cells, even though eIF2alpha is phosphorylated these granules are not formed, suggesting that the virus prevents the assembly of these structures to allow the translation of its mRNAs. Under these conditions, some of the cellular proteins that form part of these structures were found to change their intracellular localization, with some of them having dramatic changes, like the poly(A) binding protein, which relocates from the cytoplasm to the nucleus in infected cells, a relocation that depends on the viral protein NSP3.
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21
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Kalavrizioti D, Vourekas A, Drainas D. DRpp20 and DRpp40: Two protein subunits involved in Dictyostelium discoideum ribonuclease P holoenzyme assembly. Gene 2007; 400:52-9. [PMID: 17611045 DOI: 10.1016/j.gene.2007.05.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 05/04/2007] [Accepted: 05/25/2007] [Indexed: 11/25/2022]
Abstract
Ribonuclease P is an essential enzyme that matures the 5' ends of all primary tRNA transcripts. RNase P enzymes contain a similar in size RNA subunit which is absolutely required for catalysis. The holoenzyme from Dictyostelium discoideum possesses an essential for activity RNA subunit but the exact protein composition is still under investigation. Bioinformatic analysis of D. discoideum sequencing data returned seven ORFs homologous to previously characterized RNase P protein subunits from human. In the present study, DRpp20 and DRpp40 were cloned and characterized. These proteins apart from the noted similarity possess idiosyncratic regions. Immunobiochemical analysis presented herein indicates their direct involvement in the formation of the ribonucleoprotein complex of D. discoideum RNase P holoenzyme.
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Affiliation(s)
- Dimitra Kalavrizioti
- Department of Biochemistry, School of Medicine, University of Patras, 1 Asklipiou st., Patras 26504, Greece
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22
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Wirth PhD B, Riessland Msc M, Hahnen MBA E. Drug discovery for spinal muscular atrophy. Expert Opin Drug Discov 2007; 2:437-51. [DOI: 10.1517/17460441.2.4.437] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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23
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Jarrous N, Reiner R. Human RNase P: a tRNA-processing enzyme and transcription factor. Nucleic Acids Res 2007; 35:3519-24. [PMID: 17483522 PMCID: PMC1920233 DOI: 10.1093/nar/gkm071] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ribonuclease P (RNase P) has been hitherto well known as a catalytic ribonucleoprotein that processes the 5' leader sequence of precursor tRNA. Recent studies, however, reveal a new role for nuclear forms of RNase P in the transcription of tRNA genes by RNA polymerase (pol) III, thus linking transcription with processing in the regulation of tRNA gene expression. However, RNase P is also essential for the transcription of other small noncoding RNA genes, whose precursor transcripts are not recognized as substrates for this holoenzyme. Accordingly, RNase P can act solely as a transcription factor for pol III, a role that seems to be conserved in eukarya.
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Affiliation(s)
- Nayef Jarrous
- Department of Molecular Biology, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
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24
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Welting TJM, Peters FMA, Hensen SMM, van Doorn NL, Kikkert BJ, Raats JMH, van Venrooij WJ, Pruijn GJM. Heterodimerization regulates RNase MRP/RNase P association, localization, and expression of Rpp20 and Rpp25. RNA (NEW YORK, N.Y.) 2007; 13:65-75. [PMID: 17119099 PMCID: PMC1705748 DOI: 10.1261/rna.237807] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Rpp20 and Rpp25 are subunits of the human RNase MRP and RNase P endoribonucleases belonging to the Alba superfamily of nucleic acid binding proteins. These proteins, which bind very strongly to each other, transiently associate with RNase MRP. Here, we show that the Rpp20-Rpp25 heterodimer is resistant to both high concentrations of salt and a nonionic detergent. The interaction of Rpp20 and Rpp25 with the P3 domain of the RNase MRP RNA appeared to be strongly enhanced by their heterodimerization. Coimmunoprecipitation experiments demonstrated that only a single copy of each of these proteins is associated with the RNase MRP and RNase P particles in HEp-2 cells. Both proteins accumulate in the nucleoli, which in case of Rpp20 is strongly dependent on its interaction with Rpp25. Finally, the results of overexpression and knock-down experiments indicate that their expression levels are codependent. Taken together, these data indicate that the Rpp20-Rpp25 heterodimerization regulates their RNA-binding activity, subcellular localization, and expression, which suggests that their interaction is also crucial for their role in RNase MRP/P function.
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Affiliation(s)
- Tim J M Welting
- Department of Biomolecular Chemistry, Nijmegen Center for Molecular Life Sciences, Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen, The Netherlands
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25
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Tetzlaff JE, Huppenbauer CB, Tanzer L, Alexander TD, Jones KJ. Motoneuron injury and repair: New perspectives on gonadal steroids as neurotherapeutics. J Mol Neurosci 2006; 28:53-64. [PMID: 16632875 DOI: 10.1385/jmn:28:1:53] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 11/30/1999] [Accepted: 06/28/2005] [Indexed: 12/26/2022]
Abstract
In this review, we will summarize recent work from our laboratory on the role of gonadal steroids as neuroprotective agents in motoneuron viability following cell stress. Three motoneuron models will be discussed: developing axotomized hamster facial motoneurons (FMNs); adult axotomized mouse FMNs; and immortalized, cultured mouse spinal motoneurons subjected to heat shock. New work on two relevant motoneuron proteins, the survival of motor neuron protein, and neuritin or candidate plasticity-related gene 15, indicates differential steroid regulation of these two proteins after axotomy. The concept of gonadal steroids as cellular stress correction factors and the implications of this for acute neurological injury situations will be presented as well.
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Affiliation(s)
- Julie E Tetzlaff
- Department of Cell Biology, Neurobiology, and Anatomy, Loyola University of Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
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26
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Abstract
The molecular basis of spinal muscular atrophy (SMA), an autosomal recessive neuromuscular disorder, is the homozygous loss of the survival motor neuron gene 1 (SMN1). A nearly identical copy of the SMN1 gene, called SMN2, modulates the disease severity. The functional difference between both genes is a translationally silent mutation that, however, disrupts an exonic splicing enhancer causing exon 7 skipping in most SMN2 transcripts. Only 10% of SMN2 transcripts encode functional full-length protein identical to SMN1. Transcriptional activation, facilitation of correct SMN2 splicing, or stabilization of the protein are considered as strategies for SMA therapy. Among various drugs, histone deacetylase inhibitors such as valproic acid (VPA) or 4-phenylbutyrate (PBA) have been shown to increase SMN2-derived RNA and protein levels. Recently, in vivo activation of the SMN gene was shown in VPA-treated SMA patients and carriers. Clinical trials are underway to investigate the effect of VPA and PBA on motor function in SMA patients.
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Affiliation(s)
- Brunhilde Wirth
- Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
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27
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Hua Y, Zhou J. Survival motor neuron protein facilitates assembly of stress granules. FEBS Lett 2004; 572:69-74. [PMID: 15304326 DOI: 10.1016/j.febslet.2004.07.010] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 07/02/2004] [Accepted: 07/09/2004] [Indexed: 01/24/2023]
Abstract
The survival motor neuron (SMN) protein forms cytoplasmic granules when overexpressed. We report here that SMN co-localizes with TIA-1/R and G3BP, protein assemblers of stress granules (SGs), and that SMN is co-immunoprecipitated with TIA-1/R, suggesting that SMN granules are SGs. Formation of SMN granules precedes accumulation of TIA-1/R, indicating that SMN serves as a facilitator of SG formation. However, the exon 7 skipping product, SMNDelta7, is largely retained in the nucleus and forms nuclear granules, indicating that exon 7 is critical for SG formation. Our findings reveal a novel SMN function and possible SG involvement in the pathogenesis of spinal muscular atrophy.
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Affiliation(s)
- Yimin Hua
- Department of Medicine and Program in Neuroscience, University of Massachusetts Medical School, 364 Plantation Street, LRB 325, Worcester, MA 01605, USA
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