1
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Ocharán-Mercado A, Loaeza-Loaeza J, Castro-Coronel Y, Acosta-Saavedra LC, Hernández-Kelly LC, Hernández-Sotelo D, Ortega A. RNA-Binding Proteins: A Role in Neurotoxicity? Neurotox Res 2023; 41:681-697. [PMID: 37776476 PMCID: PMC10682104 DOI: 10.1007/s12640-023-00669-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 03/15/2023] [Accepted: 09/19/2023] [Indexed: 10/02/2023]
Abstract
Despite sustained efforts to treat neurodegenerative diseases, little is known at the molecular level to understand and generate novel therapeutic approaches for these malignancies. Therefore, it is not surprising that neurogenerative diseases are among the leading causes of death in the aged population. Neurons require sophisticated cellular mechanisms to maintain proper protein homeostasis. These cells are generally sensitive to loss of gene expression control at the post-transcriptional level. Post-translational control responds to signals that can arise from intracellular processes or environmental factors that can be regulated through RNA-binding proteins. These proteins recognize RNA through one or more RNA-binding domains and form ribonucleoproteins that are critically involved in the regulation of post-transcriptional processes from splicing to the regulation of association of the translation machinery allowing a relatively rapid and precise modulation of the transcriptome. Neurotoxicity is the result of the biological, chemical, or physical interaction of agents with an adverse effect on the structure and function of the central nervous system. The disruption of the proper levels or function of RBPs in neurons and glial cells triggers neurotoxic events that are linked to neurodegenerative diseases such as spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), fragile X syndrome (FXS), and frontotemporal dementia (FTD) among many others. The connection between RBPs and neurodegenerative diseases opens a new landscape for potentially novel therapeutic targets for the intervention of these neurodegenerative pathologies. In this contribution, a summary of the recent findings of the molecular mechanisms involved in the plausible role of RBPs in RNA processing in neurodegenerative disease is discussed.
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Affiliation(s)
- Andrea Ocharán-Mercado
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México
| | - Jaqueline Loaeza-Loaeza
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México
| | - Yaneth Castro-Coronel
- Laboratorio de Epigenética del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas 88, Chilpancingo, Guerrero, 39086, México
| | - Leonor C Acosta-Saavedra
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México
| | - Luisa C Hernández-Kelly
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México
| | - Daniel Hernández-Sotelo
- Laboratorio de Epigenética del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas 88, Chilpancingo, Guerrero, 39086, México
| | - Arturo Ortega
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México.
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2
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Chen X, Wu J, Li Z, Han J, Xia P, Shen Y, Ma J, Liu X, Zhang J, Yu P. Advances in The Study of RNA-binding Proteins in Diabetic Complications. Mol Metab 2022; 62:101515. [PMID: 35597446 PMCID: PMC9168169 DOI: 10.1016/j.molmet.2022.101515] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/21/2022] [Accepted: 05/12/2022] [Indexed: 12/18/2022] Open
Abstract
Background It has been reported that diabetes mellitus affects 435 million people globally as a primary health care problem. Despite many therapies available, many diabetes remains uncontrolled, giving rise to irreversible diabetic complications that pose significant risks to patients’ wellbeing and survival. Scope of Review In recent years, as much effort is put into elucidating the posttranscriptional gene regulation network of diabetes and diabetic complications; RNA binding proteins (RBPs) are found to be vital. RBPs regulate gene expression through various post-transcriptional mechanisms, including alternative splicing, RNA export, messenger RNA translation, RNA degradation, and RNA stabilization. Major Conclusions Here, we summarized recent studies on the roles and mechanisms of RBPs in mediating abnormal gene expression in diabetes and its complications. Moreover, we discussed the potential and theoretical basis of RBPs to treat diabetes and its complications. • Mechanisms of action of RBPs involved in diabetic complications are summarized and elucidated. • We discuss the theoretical basis and potential of RBPs for the treatment of diabetes and its complications. • We summarize the possible effective drugs for diabetes based on RBPs promoting the development of future therapeutic drugs.
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Affiliation(s)
- Xinyue Chen
- The Second Clinical Medical College of Nanchang University, the Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jiaqiang Wu
- The Second Clinical Medical College of Nanchang University, the Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Zhangwang Li
- The Second Clinical Medical College of Nanchang University, the Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jiashu Han
- Department of Thoracic Surgery, Peking Union Medical College Hospital, Beijing 100730, China
| | - Panpan Xia
- Department of Metabolism and Endocrinology, the Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Yunfeng Shen
- Department of Metabolism and Endocrinology, the Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jianyong Ma
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, USA
| | - Xiao Liu
- Department of Cardiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jing Zhang
- The Second Clinical Medical College of Nanchang University, the Second Affiliated Hospital of Nanchang University, Nanchang, China; Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Jiangxi, Nanchang 330006, China.
| | - Peng Yu
- The Second Clinical Medical College of Nanchang University, the Second Affiliated Hospital of Nanchang University, Nanchang, China; Department of Metabolism and Endocrinology, the Second Affiliated Hospital of Nanchang University, Nanchang, China.
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3
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Accurate identification of circRNA landscape and complexity reveals their pivotal roles in human oligodendroglia differentiation. Genome Biol 2022; 23:48. [PMID: 35130952 PMCID: PMC8819885 DOI: 10.1186/s13059-022-02621-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 01/26/2022] [Indexed: 01/22/2023] Open
Abstract
Background Circular RNAs (circRNAs), a novel class of poorly conserved non-coding RNAs that regulate gene expression, are highly enriched in the human brain. Despite increasing discoveries of circRNA function in human neurons, the circRNA landscape and function in developing human oligodendroglia, the myelinating cells that govern neuronal conductance, remains unexplored. Meanwhile, improved experimental and computational tools for the accurate identification of circRNAs are needed. Results We adopt a published experimental approach for circRNA enrichment and develop CARP (CircRNA identification using A-tailing RNase R approach and Pseudo-reference alignment), a comprehensive 21-module computational framework for accurate circRNA identification and quantification. Using CARP, we identify developmentally programmed human oligodendroglia circRNA landscapes in the HOG oligodendroglioma cell line, distinct from neuronal circRNA landscapes. Numerous circRNAs display oligodendroglia-specific regulation upon differentiation, among which a subclass is regulated independently from their parental mRNAs. We find that circRNA flanking introns often contain cis-regulatory elements for RNA editing and are predicted to bind differentiation-regulated splicing factors. In addition, we discover novel oligodendroglia-specific circRNAs that are predicted to sponge microRNAs, which co-operatively promote oligodendroglia development. Furthermore, we identify circRNA clusters derived from differentiation-regulated alternative circularization events within the same gene, each containing a common circular exon, achieving additive sponging effects that promote human oligodendroglia differentiation. Conclusions Our results reveal dynamic regulation of human oligodendroglia circRNA landscapes during early differentiation and suggest critical roles of the circRNA-miRNA-mRNA axis in advancing human oligodendroglia development. Supplementary Information The online version contains supplementary material available at 10.1186/s13059-022-02621-1.
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4
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Neumann DP, Goodall GJ, Gregory PA. The Quaking RNA-binding proteins as regulators of cell differentiation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1724. [PMID: 35298877 PMCID: PMC9786888 DOI: 10.1002/wrna.1724] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 12/30/2022]
Abstract
The RNA-binding protein Quaking (QKI) has emerged as a potent regulator of cellular differentiation in developmental and pathological processes. The QKI gene is itself alternatively spliced to produce three major isoforms, QKI-5, QKI-6, and QKI-7, that possess very distinct functions. Here, we highlight roles of the different QKI isoforms in neuronal, vascular, muscle, and monocyte cell differentiation, and during epithelial-mesenchymal transition in cancer progression. QKI isoforms control cell differentiation through regulating alternative splicing, mRNA stability and translation, with activities in gene transcription now also becoming evident. These diverse functions of the QKI isoforms contribute to their broad influences on RNA metabolism and cellular differentiation. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Processing > Splicing Regulation/Alternative Splicing RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Daniel P. Neumann
- Centre for Cancer BiologyUniversity of South Australia and SA PathologyAdelaideSouth Australia
| | - Gregory J. Goodall
- Centre for Cancer BiologyUniversity of South Australia and SA PathologyAdelaideSouth Australia,Faculty of Health and Medical SciencesThe University of AdelaideAdelaideSouth Australia
| | - Philip A. Gregory
- Centre for Cancer BiologyUniversity of South Australia and SA PathologyAdelaideSouth Australia,Faculty of Health and Medical SciencesThe University of AdelaideAdelaideSouth Australia
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5
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Liu R, Li H, Deng J, Wu Q, Liao C, Xiao Q, Chang Q. QKI 6 ameliorates CIRI through promoting synthesis of triglyceride in neuron and inhibiting neuronal apoptosis associated with SIRT1-PPARγ-PGC-1α axis. Brain Behav 2021; 11:e2271. [PMID: 34227244 PMCID: PMC8413718 DOI: 10.1002/brb3.2271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/17/2021] [Accepted: 06/17/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The stroke induced by ischemia of brain remains high incidence and death rate. The study wanted to confirm the effects of Quaking 6 (QKI 6) on the protection role in neurons of rat model of cerebral ischemia/reperfusion injury (CIRI). MATERIAL AND METHODS The rat model with CIRI induced by middle cerebral artery occlusion was well established and rat neurons were isolated to characterize the effects of QKI 6 mediated by sirtuin 1 (SIRT1) on synthesis of triglyceride in neuron and neuronal apoptosis via activation of SIRT1-peroxisome proliferater-activated receptor (PPAR)γ- peroxisome proliferator-activated receptor coactivator (PGC)-1α signaling pathway. RESULTS The expression levels of SIRT1 or QKI 6, and acetylation level of QKI 6 were decreased in neurons of rat model with CIRI. QKI 6 deacetylated and mediated by SIRT1 that contributed to suppressing the progression of neuronal apoptosis in rat through promoting synthesis of triglyceride in vivo and in vitro via SIRT1-PPARγ-PGC-1α signaling pathway, then inhibiting CIRI. CONCLUSIONS Our results demonstrated SIRT1 deacetylates QKI 6, the RNA-binding protein, that affects significantly the synthesis of triglyceride in neurons of CIRI rat model. Moreover, it activated transcription factor peroxisome proliferator-activated receptorγ coactivator-1α (PGC-1α) through post-transcriptional regulation of the expression of PPARγ, and further enhanced synthesis of triglyceride, thereby restrained the progression of neural apoptosis and CIRI.
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Affiliation(s)
- Rui Liu
- Department of Rehabilitation, Tangdu Hospital, Fourth Military Medical University, Xi'an, PR China
| | - Hongzeng Li
- Department of Gerontology, Tangdu Hospital, Fourth Military Medical University, Xi'an, PR China
| | - Jingyuan Deng
- Department of Encephalology, the First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, PR China
| | - Qunqiang Wu
- Department of Rehabilitation, Tangdu Hospital, Fourth Military Medical University, Xi'an, PR China
| | - Chunhua Liao
- Department of Rehabilitation, Tangdu Hospital, Fourth Military Medical University, Xi'an, PR China
| | - Qun Xiao
- Department of Rehabilitation, Tangdu Hospital, Fourth Military Medical University, Xi'an, PR China
| | - Qi Chang
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an, PR China.,Department of Orthopaedics, The 150th Central Hospital of Chinese People's Liberation Army, Luoyang, PR China
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6
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Ng SS, Park JE, Meng W, Chen CP, Kalaria RN, McCarthy NE, Sze SK. Pulsed SILAM Reveals In Vivo Dynamics of Murine Brain Protein Translation. ACS OMEGA 2020; 5:13528-13540. [PMID: 32566817 PMCID: PMC7301365 DOI: 10.1021/acsomega.9b04439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/08/2020] [Indexed: 06/11/2023]
Abstract
Identification of proteins that are synthesized de novo in response to specific microenvironmental cues is critical for understanding molecular mechanisms that underpin vital physiological processes and pathologies. Here, we report that a brief period of SILAM (Stable Isotope Labeling of Mammals) diet enables the determination of biological functions corresponding to actively translating proteins in the mouse brain. Our results demonstrate that the synapse, dendrite, and myelin sheath are highly active neuronal structures that display rapid protein synthesis, producing key mediators of chemical signaling as well as nutrient sensing, lipid metabolism, and amyloid precursor protein processing/stability. Together, these findings confirm that protein metabolic activity varies significantly between brain functional units in vivo. Our data indicate that pulsed SILAM approaches can unravel complex protein expression dynamics in the murine brain and identify active synthetic pathways and associated functions that are likely impaired in neurodegenerative diseases.
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Affiliation(s)
- Ser Sue Ng
- School
of Biological Sciences, Nanyang Technological
University, 60 Nanyang Drive, 637551 Singapore
| | - Jung Eun Park
- School
of Biological Sciences, Nanyang Technological
University, 60 Nanyang Drive, 637551 Singapore
| | - Wei Meng
- School
of Biological Sciences, Nanyang Technological
University, 60 Nanyang Drive, 637551 Singapore
| | - Christopher P. Chen
- Memory,
Aging and Cognition Centre, National University
Health System, 1E Kent
Ridge Road, 119228 Singapore
- Department
of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Blk MD3, 16 Medical Drive, 117600 Singapore
| | - Raj N. Kalaria
- Institute
of Neuroscience, Campus for Ageing and Vitality, Newcastle University, Newcastle
upon Tyne NE4 5PL, U.K.
| | - Neil E. McCarthy
- Centre
for Immunobiology, The Blizard Institute, Bart’s and The London
School of Medicine and Dentistry, Queen
Mary University of London, 4 Newark St, London E1
2AT, U.K.
| | - Siu Kwan Sze
- School
of Biological Sciences, Nanyang Technological
University, 60 Nanyang Drive, 637551 Singapore
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7
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Lavon I, Leykin I, Charbit H, Binyamin O, Brill L, Ovadia H, Vaknin-Dembinsky A. QKI-V5 is downregulated in CNS inflammatory demyelinating diseases. Mult Scler Relat Disord 2019; 39:101881. [PMID: 31835207 DOI: 10.1016/j.msard.2019.101881] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/25/2019] [Accepted: 11/30/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND Neuromyelitis-optica (NMO) and multiple-sclerosis (MS) are inflammatory- demyelinating-diseases of the central-nervous-system (CNS). In a previous study, we identified 17 miRNAs that were significantly upregulated in the peripheral blood of patients with NMO, relative to healthy controls (HCs). Target gene analysis have demonstrated that QKI is targeted by 70% of the upregulated miRNAs. QKI gene encodes for a RNA-binding-protein that plays a central role in myelination. QKI variants 5, 6, 7 (QKI-V5, QKI-V6, QKI-V7) are generated via alternative splicing. Given the role played by QKI in myelination we aimed to study the expression levels of QKI variants in the circulation of patients with NMO and MS and in the circulation and brain tissue of mice-model to CNS-inflammatory-demyelinating-disease. METHODS RNA and protein expression levels of QKI variants QKI-V5, QKI-V6 and QKI-V7 were determined in the blood of patients with NMO (n = 23) or MS (n = 13). The effect of sera from patients on the expression of QKI in normal peripheral-blood-mononuclear-cells (PBMCs) or glial cells was explored. The mog-experimental-autoimmune-encephalomyelitis (EAE) mouse model was used to study the correlation between the changes in the expression levels of QKI in the blood to those in the brain. RESULTS RNA and protein expression of QKI-V5 was decreased in the peripheral blood of patients with NMO and multiple-sclerosis. Incubation of normal peripheral-blood-mononuclear-cells or glial cells with sera of patients significantly reduced the expression of QKI-V5. The blood and brain of EAE mice exhibited a corresponding decrease in QKI-V5 expression. CONCLUSION The downregulation in the expression of QKI-V5 in the blood of patients with CNS-inflammatory-demyelinating-diseases and in the brain and blood of EAE mice is likely caused by a circulating factor and might promote re-myelination by regulation of myelin-associated genes. Key words: QKI variants, Multiple sclerosis (MS), Neuromyelitis optica (NMO), Astrocytes, Demyelination.
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Affiliation(s)
- Iris Lavon
- Department of Neurology, the Agnes-Ginges Center for Neurogenetics, Hadassah- Medical Center, Hebrew University, Jerusalem, Israel; Leslie and Michael Center for Neuro-oncology, Hadassah-Medical Center, Jerusalem, Israel.
| | - Ina Leykin
- Department of Neurology, the Agnes-Ginges Center for Neurogenetics, Hadassah- Medical Center, Hebrew University, Jerusalem, Israel; Leslie and Michael Center for Neuro-oncology, Hadassah-Medical Center, Jerusalem, Israel
| | - Hanna Charbit
- Department of Neurology, the Agnes-Ginges Center for Neurogenetics, Hadassah- Medical Center, Hebrew University, Jerusalem, Israel; Leslie and Michael Center for Neuro-oncology, Hadassah-Medical Center, Jerusalem, Israel
| | - Orli Binyamin
- Department of Neurology, the Agnes-Ginges Center for Neurogenetics, Hadassah- Medical Center, Hebrew University, Jerusalem, Israel
| | - Livnat Brill
- Department of Neurology, the Agnes-Ginges Center for Neurogenetics, Hadassah- Medical Center, Hebrew University, Jerusalem, Israel
| | - Haim Ovadia
- Department of Neurology, the Agnes-Ginges Center for Neurogenetics, Hadassah- Medical Center, Hebrew University, Jerusalem, Israel
| | - Adi Vaknin-Dembinsky
- Department of Neurology, the Agnes-Ginges Center for Neurogenetics, Hadassah- Medical Center, Hebrew University, Jerusalem, Israel
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8
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Ramanathan M, Majzoub K, Rao DS, Neela PH, Zarnegar BJ, Mondal S, Roth JG, Gai H, Kovalski JR, Siprashvili Z, Palmer TD, Carette JE, Khavari PA. RNA-protein interaction detection in living cells. Nat Methods 2018; 15:207-212. [PMID: 29400715 DOI: 10.1038/nmeth.4601] [Citation(s) in RCA: 206] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 12/19/2017] [Indexed: 12/30/2022]
Abstract
RNA-protein interactions play numerous roles in cellular function and disease. Here we describe RNA-protein interaction detection (RaPID), which uses proximity-dependent protein labeling, based on the BirA* biotin ligase, to rapidly identify the proteins that bind RNA sequences of interest in living cells. RaPID displays utility in multiple applications, including in evaluating protein binding to mutant RNA motifs in human genetic disorders, in uncovering potential post-transcriptional networks in breast cancer, and in discovering essential host proteins that interact with Zika virus RNA. To improve the BirA*-labeling component of RaPID, moreover, a new mutant BirA* was engineered from Bacillus subtilis, termed BASU, that enables >1,000-fold faster kinetics and >30-fold increased signal-to-noise ratio over the prior standard Escherichia coli BirA*, thereby enabling direct study of RNA-protein interactions in living cells on a timescale as short as 1 min.
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Affiliation(s)
- Muthukumar Ramanathan
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Karim Majzoub
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Deepti S Rao
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Poornima H Neela
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Brian J Zarnegar
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Smarajit Mondal
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Julien G Roth
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA
| | - Hui Gai
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA
| | - Joanna R Kovalski
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Zurab Siprashvili
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Theo D Palmer
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA
| | - Jan E Carette
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Paul A Khavari
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California, USA.,Veterans Affairs Palo Alto Healthcare System, Palo Alto, California, USA
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9
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Levene M, Enguita FJ, Bax BE. Discovery profiling and bioinformatics analysis of serum microRNA in Mitochondrial NeuroGastroIntestinal Encephalomyopathy (MNGIE). NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2018; 37:618-629. [PMID: 30587073 DOI: 10.1080/15257770.2018.1492138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare and fatal inherited metabolic disorder due to mutations in the nuclear TYMP gene and leads to a deficiency in the enzyme thymidine phosphorylase. This results in an accumulation of the deoxynucleosides, thymidine and deoxyuridine in the cellular and extracellular compartments, ultimately leading to mitochondrial failure. The understanding of the precise molecular mechanisms that underlie the disease pathology is limited, being hampered by the rarity of the disorder. Expression profiling of serum based mircoRNAs and subsequent bioinformatical analyses provide an approach to facilitate the identity of dysregulated genes and signalling pathways potentially involved in the pathogenesis of MNGIE.
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Affiliation(s)
- Michelle Levene
- a Cell Biology and Genetics Research Centre , St George's University of London, Molecular and Cell Sciences Institute , London , United Kingdom
| | - Francisco J Enguita
- b Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa , Lisboa , Portugal
| | - Bridget E Bax
- a Cell Biology and Genetics Research Centre , St George's University of London, Molecular and Cell Sciences Institute , London , United Kingdom
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10
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Hayakawa-Yano Y, Suyama S, Nogami M, Yugami M, Koya I, Furukawa T, Zhou L, Abe M, Sakimura K, Takebayashi H, Nakanishi A, Okano H, Yano M. An RNA-binding protein, Qki5, regulates embryonic neural stem cells through pre-mRNA processing in cell adhesion signaling. Genes Dev 2017; 31:1910-1925. [PMID: 29021239 PMCID: PMC5693031 DOI: 10.1101/gad.300822.117] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 09/14/2017] [Indexed: 01/07/2023]
Abstract
Cell type-specific transcriptomes are enabled by the action of multiple regulators, which are frequently expressed within restricted tissue regions. In the present study, we identify one such regulator, Quaking 5 (Qki5), as an RNA-binding protein (RNABP) that is expressed in early embryonic neural stem cells and subsequently down-regulated during neurogenesis. mRNA sequencing analysis in neural stem cell culture indicates that Qki proteins play supporting roles in the neural stem cell transcriptome and various forms of mRNA processing that may result from regionally restricted expression and subcellular localization. Also, our in utero electroporation gain-of-function study suggests that the nuclear-type Qki isoform Qki5 supports the neural stem cell state. We next performed in vivo transcriptome-wide protein-RNA interaction mapping to search for direct targets of Qki5 and elucidate how Qki5 regulates neural stem cell function. Combined with our transcriptome analysis, this mapping analysis yielded a bona fide map of Qki5-RNA interaction at single-nucleotide resolution, the identification of 892 Qki5 direct target genes, and an accurate Qki5-dependent alternative splicing rule in the developing brain. Last, our target gene list provides the first compelling evidence that Qki5 is associated with specific biological events; namely, cell-cell adhesion. This prediction was confirmed by histological analysis of mice in which Qki proteins were genetically ablated, which revealed disruption of the apical surface of the lateral wall in the developing brain. These data collectively indicate that Qki5 regulates communication between neural stem cells by mediating numerous RNA processing events and suggest new links between splicing regulation and neural stem cell states.
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Affiliation(s)
- Yoshika Hayakawa-Yano
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Satoshi Suyama
- Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Masahiro Nogami
- Shonan Incubation Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan.,Integrated Technology Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan
| | - Masato Yugami
- Shonan Incubation Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan.,Integrated Technology Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan
| | - Ikuko Koya
- Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Takako Furukawa
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Li Zhou
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8585, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8585, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8585, Japan
| | - Hirohide Takebayashi
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Atsushi Nakanishi
- Shonan Incubation Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan.,Integrated Technology Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Masato Yano
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan.,Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
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11
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Fagg WS, Liu N, Fair JH, Shiue L, Katzman S, Donohue JP, Ares M. Autogenous cross-regulation of Quaking mRNA processing and translation balances Quaking functions in splicing and translation. Genes Dev 2017; 31:1894-1909. [PMID: 29021242 PMCID: PMC5695090 DOI: 10.1101/gad.302059.117] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 09/11/2017] [Indexed: 12/18/2022]
Abstract
Quaking protein isoforms arise from a single Quaking gene and bind the same RNA motif to regulate splicing, translation, decay, and localization of a large set of RNAs. However, the mechanisms by which Quaking expression is controlled to ensure that appropriate amounts of each isoform are available for such disparate gene expression processes are unknown. Here we explore how levels of two isoforms, nuclear Quaking-5 (Qk5) and cytoplasmic Qk6, are regulated in mouse myoblasts. We found that Qk5 and Qk6 proteins have distinct functions in splicing and translation, respectively, enforced through differential subcellular localization. We show that Qk5 and Qk6 regulate distinct target mRNAs in the cell and act in distinct ways on their own and each other's transcripts to create a network of autoregulatory and cross-regulatory feedback controls. Morpholino-mediated inhibition of Qk translation confirms that Qk5 controls Qk RNA levels by promoting accumulation and alternative splicing of Qk RNA, whereas Qk6 promotes its own translation while repressing Qk5. This Qk isoform cross-regulatory network responds to additional cell type and developmental controls to generate a spectrum of Qk5/Qk6 ratios, where they likely contribute to the wide range of functions of Quaking in development and cancer.
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Affiliation(s)
- W Samuel Fagg
- Sinsheimer Laboratories, Department of Molecular, Cell, and Developmental Biology, Center for Molecular Biology of RNA, University of California at Santa Cruz. Santa Cruz, California 95064, USA.,Department of Surgery, Transplant Division, Shriners Hospital for Children, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Naiyou Liu
- Department of Surgery, Transplant Division, Shriners Hospital for Children, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Jeffrey Haskell Fair
- Department of Surgery, Transplant Division, Shriners Hospital for Children, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Lily Shiue
- Sinsheimer Laboratories, Department of Molecular, Cell, and Developmental Biology, Center for Molecular Biology of RNA, University of California at Santa Cruz. Santa Cruz, California 95064, USA
| | - Sol Katzman
- Sinsheimer Laboratories, Department of Molecular, Cell, and Developmental Biology, Center for Molecular Biology of RNA, University of California at Santa Cruz. Santa Cruz, California 95064, USA
| | - John Paul Donohue
- Sinsheimer Laboratories, Department of Molecular, Cell, and Developmental Biology, Center for Molecular Biology of RNA, University of California at Santa Cruz. Santa Cruz, California 95064, USA
| | - Manuel Ares
- Sinsheimer Laboratories, Department of Molecular, Cell, and Developmental Biology, Center for Molecular Biology of RNA, University of California at Santa Cruz. Santa Cruz, California 95064, USA
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12
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Shu P, Fu H, Zhao X, Wu C, Ruan X, Zeng Y, Liu W, Wang M, Hou L, Chen P, Yin B, Yuan J, Qiang B, Peng X. MicroRNA-214 modulates neural progenitor cell differentiation by targeting Quaking during cerebral cortex development. Sci Rep 2017; 7:8014. [PMID: 28808337 PMCID: PMC5556025 DOI: 10.1038/s41598-017-08450-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/10/2017] [Indexed: 01/30/2023] Open
Abstract
The accurate generation of an appropriate number of different neuronal and glial subtypes is fundamental to normal brain functions and requires tightly orchestrated spatial and temporal developmental programmes to maintain the balance between the proliferation and the differentiation of neural progenitor cells. However, the molecular mechanism governing this process has not been fully elucidated. Here, we found that miR-214-3p was highly expressed in neural progenitor cells and dynamically regulated during neocortical development. Moreover, our in vivo and in vitro studies showed that miR-214 inhibited self-renewal of neural progenitor cells and promoted neurogenesis. In addition, after target screening, we identified miR-214 targets including Quaking (Qki) by binding the 3'- untranslated region (3'-UTR) of the Qki mRNA, which was specifically expressed in the progenitor cells of the proliferative ventricular zone as 3 Qki isoforms. Furthermore, overexpression and knockdown of Qki showed that the different isoforms of Qki had different functions in the regulation of neural progenitor cells differentiation. Moreover, overexpression of Qki could counteract the function of miR-214 in neurogenesis. Our results revealed that miR-214 maintains the balance between neural progenitor/stem cell proliferation and differentiation together with Quaking, its target gene.
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Affiliation(s)
- Pengcheng Shu
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Hongye Fu
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Xiangyu Zhao
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Chao Wu
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Xiangbin Ruan
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Yi Zeng
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Wei Liu
- Department of Anatomy and Histology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Ming Wang
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Lin Hou
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Pan Chen
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Bin Yin
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Jiangang Yuan
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Boqin Qiang
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Xiaozhong Peng
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China.
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13
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Transcriptome profiling of mouse brains with qkI-deficient oligodendrocytes reveals major alternative splicing defects including self-splicing. Sci Rep 2017; 7:7554. [PMID: 28790308 PMCID: PMC5548867 DOI: 10.1038/s41598-017-06211-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 06/08/2017] [Indexed: 12/31/2022] Open
Abstract
The qkI gene encodes a family of RNA binding proteins alternatively spliced at its 3′ end, giving rise to three major spliced isoforms: QKI-5, QKI-6 and QKI-7. Their expression is tightly regulated during brain development with nuclear QKI-5 being the most abundant during embryogenesis followed by QKI-6 and QKI-7 that peak during myelination. Previously, we generated a mouse conditional qkI allele where exon 2 is excised using Olig2-Cre resulting in QKI-deficient oligodendrocytes (OLs). These mice have dysmyelination and die at the third post-natal week. Herein, we performed a transcriptomic analysis of P14 mouse brains of QKI-proficient (QKIFL/FL;-) and QKI-deficient (QKIFL/FL;Olig2-Cre) OLs. QKI deficiency results in major global changes of gene expression and RNA processing with >1,800 differentially expressed genes with the top categories being axon ensheathment and myelination. Specific downregulated genes included major myelin proteins, suggesting that the QKI proteins are key regulators of RNA metabolism in OLs. We also identify 810 alternatively spliced genes including known QKI targets, MBP and Nfasc. Interestingly, we observe in QKIFL/FL;Olig2-Cre a switch in exon 2-deficient qkI mRNAs favoring the expression of the qkI-5 rather than the qkI-6 and qkI-7. These findings define QKI as regulators of alternative splicing in OLs including self-splicing.
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14
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Thangaraj MP, Furber KL, Gan JK, Ji S, Sobchishin L, Doucette JR, Nazarali AJ. RNA-binding Protein Quaking Stabilizes Sirt2 mRNA during Oligodendroglial Differentiation. J Biol Chem 2017; 292:5166-5182. [PMID: 28188285 DOI: 10.1074/jbc.m117.775544] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Indexed: 11/06/2022] Open
Abstract
Myelination is controlled by timely expression of genes involved in the differentiation of oligodendrocyte precursor cells (OPCs) into myelinating oligodendrocytes (OLs). Sirtuin 2 (SIRT2), a NAD+-dependent deacetylase, plays a critical role in OL differentiation by promoting both arborization and downstream expression of myelin-specific genes. However, the mechanisms involved in regulating SIRT2 expression during OL development are largely unknown. The RNA-binding protein quaking (QKI) plays an important role in myelination by post-transcriptionally regulating the expression of several myelin specific genes. In quaking viable (qkv/qkv ) mutant mice, SIRT2 protein is severely reduced; however, it is not known whether these genes interact to regulate OL differentiation. Here, we report for the first time that QKI directly binds to Sirt2 mRNA via a common quaking response element (QRE) located in the 3' untranslated region (UTR) to control SIRT2 expression in OL lineage cells. This interaction is associated with increased stability and longer half-lives of Sirt2.1 and Sirt2.2 transcripts leading to increased accumulation of Sirt2 transcripts. Consistent with this, overexpression of qkI promoted the expression of Sirt2 mRNA and protein. However, overexpression of the nuclear isoform qkI-5 promoted the expression of Sirt2 mRNA, but not SIRT2 protein, and delayed OL differentiation. These results suggest that the balance in the subcellular distribution and temporal expression of QKI isoforms control the availability of Sirt2 mRNA for translation. Collectively, our study demonstrates that QKI directly plays a crucial role in the post-transcriptional regulation and expression of Sirt2 to facilitate OL differentiation.
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Affiliation(s)
- Merlin P Thangaraj
- From the Laboratory of Molecular Cell Biology, College of Pharmacy and Nutrition and.,the Neuroscience Research Cluster, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Kendra L Furber
- From the Laboratory of Molecular Cell Biology, College of Pharmacy and Nutrition and.,the Neuroscience Research Cluster, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Jotham K Gan
- From the Laboratory of Molecular Cell Biology, College of Pharmacy and Nutrition and.,the Neuroscience Research Cluster, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Shaoping Ji
- From the Laboratory of Molecular Cell Biology, College of Pharmacy and Nutrition and.,the Neuroscience Research Cluster, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.,the Department of Biochemistry and Molecular Biology, Medical School, Henan University, Kaifeng 475004, China
| | - Larhonda Sobchishin
- From the Laboratory of Molecular Cell Biology, College of Pharmacy and Nutrition and.,the Neuroscience Research Cluster, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - J Ronald Doucette
- the Neuroscience Research Cluster, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.,Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.,the Cameco Multiple Sclerosis Neuroscience Research Center, City Hospital, Saskatoon, Saskatchewan S7K 0M7, Canada, and
| | - Adil J Nazarali
- From the Laboratory of Molecular Cell Biology, College of Pharmacy and Nutrition and .,the Neuroscience Research Cluster, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.,the Cameco Multiple Sclerosis Neuroscience Research Center, City Hospital, Saskatoon, Saskatchewan S7K 0M7, Canada, and
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15
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Radomska KJ, Sager J, Farnsworth B, Tellgren-Roth Å, Tuveri G, Peuckert C, Kettunen P, Jazin E, Emilsson LS. Characterization and Expression of the Zebrafish qki Paralogs. PLoS One 2016; 11:e0146155. [PMID: 26727370 PMCID: PMC4699748 DOI: 10.1371/journal.pone.0146155] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 12/13/2015] [Indexed: 11/21/2022] Open
Abstract
Quaking (QKI) is an RNA-binding protein involved in post-transcriptional mRNA processing. This gene is found to be associated with several human neurological disorders. Early expression of QKI proteins in the developing mouse neuroepithelium, together with neural tube defects in Qk mouse mutants, suggest the functional requirement of Qk for the establishment of the nervous system. As a knockout of Qk is embryonic lethal in mice, other model systems like the zebrafish could serve as a tool to study the developmental functions of qki. In the present study we sought to characterize the evolutionary relationship and spatiotemporal expression of qkia, qki2, and qkib; zebrafish homologs of human QKI. We found that qkia is an ancestral paralog of the single tetrapod Qk gene that was likely lost during the fin-to-limb transition. Conversely, qkib and qki2 are orthologs, emerging at the root of the vertebrate and teleost lineage, respectively. Both qki2 and qkib, but not qkia, were expressed in the progenitor domains of the central nervous system, similar to expression of the single gene in mice. Despite having partially overlapping expression domains, each gene has a unique expression pattern, suggesting that these genes have undergone subfunctionalization following duplication. Therefore, we suggest the zebrafish could be used to study the separate functions of qki genes during embryonic development.
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Affiliation(s)
- Katarzyna J. Radomska
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Jonathan Sager
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Bryn Farnsworth
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Åsa Tellgren-Roth
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Giulia Tuveri
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Christiane Peuckert
- Department of Neuroscience, Uppsala Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Petronella Kettunen
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Neuropathology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Elena Jazin
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Lina S. Emilsson
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- * E-mail:
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16
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Becherel OJ, Sun J, Yeo AJ, Nayler S, Fogel BL, Gao F, Coppola G, Criscuolo C, De Michele G, Wolvetang E, Lavin MF. A new model to study neurodegeneration in ataxia oculomotor apraxia type 2. Hum Mol Genet 2015; 24:5759-74. [PMID: 26231220 PMCID: PMC4581605 DOI: 10.1093/hmg/ddv296] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 06/12/2015] [Accepted: 07/20/2015] [Indexed: 12/18/2022] Open
Abstract
Ataxia oculomotor apraxia type 2 (AOA2) is a rare autosomal recessive cerebellar ataxia. Recent evidence suggests that the protein defective in this syndrome, senataxin (SETX), functions in RNA processing to protect the integrity of the genome. To date, only patient-derived lymphoblastoid cells, fibroblasts and SETX knockdown cells were available to investigate AOA2. Recent disruption of the Setx gene in mice did not lead to neurobehavioral defects or neurodegeneration, making it difficult to study the etiology of AOA2. To develop a more relevant neuronal model to study neurodegeneration in AOA2, we derived neural progenitors from a patient with AOA2 and a control by induced pluripotent stem cell (iPSC) reprogramming of fibroblasts. AOA2 iPSC and neural progenitors exhibit increased levels of oxidative damage, DNA double-strand breaks, increased DNA damage-induced cell death and R-loop accumulation. Genome-wide expression and weighted gene co-expression network analysis in these neural progenitors identified both previously reported and novel affected genes and cellular pathways associated with senataxin dysfunction and the pathophysiology of AOA2, providing further insight into the role of senataxin in regulating gene expression on a genome-wide scale. These data show that iPSCs can be generated from patients with the autosomal recessive ataxia, AOA2, differentiated into neurons, and that both cell types recapitulate the AOA2 cellular phenotype. This represents a novel and appropriate model system to investigate neurodegeneration in this syndrome.
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Affiliation(s)
- Olivier J Becherel
- UQ Centre for Clinical Research (UQCCR), School of Chemistry and Molecular Biosciences and
| | - Jane Sun
- Australian Institute for Bioengineering and Nanotechnology
| | - Abrey J Yeo
- UQ Centre for Clinical Research (UQCCR), School of Medicine, The University of Queensland, Brisbane, QLD 4029, Australia
| | - Sam Nayler
- Australian Institute for Bioengineering and Nanotechnology
| | | | - Fuying Gao
- Department of Psychiatry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA and
| | - Giovanni Coppola
- Department of Neurology and Department of Psychiatry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA and
| | - Chiara Criscuolo
- Department of Neuroscience and Reproductive and Odontostomatological Sciences, Federico II University, Napoli, Italy
| | - Giuseppe De Michele
- Department of Neuroscience and Reproductive and Odontostomatological Sciences, Federico II University, Napoli, Italy
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17
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RNA-binding proteins in neurological diseases. SCIENCE CHINA-LIFE SCIENCES 2014; 57:432-44. [DOI: 10.1007/s11427-014-4647-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 02/25/2014] [Indexed: 12/12/2022]
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18
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Preparation and characterizations of polyclonal antibodies against STAR protein QKI7b. Appl Biochem Biotechnol 2013; 169:2273-80. [PMID: 23440637 DOI: 10.1007/s12010-012-0081-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 12/27/2012] [Indexed: 01/05/2023]
Abstract
Quaking (QKI) proteins are important regulators of RNA metabolism and cellular signal transduction. Recent studies have shown that isoforms of QKI proteins, which include QKI5/6/7/7b in human cells, play important roles in the development of neurological diseases and human cancers. In comparison with QKI5/6/7, however, there are little data on QKI7b due to lack of specific antibodies. Here, we reported the preparation and initial characterizations of polyclonal antibodies against human QKI7b. Utilizing a chemically synthesized C-terminal peptide fragment of human QKI7b, we raised two preparations of rabbit antiserum. We found that these antibodies were able to recognize human QKI7b, but not QKI5/6/7. Our immunofluorescence staining showed that in LO2 hepatocytes, QKI7b localizes predominantly in the perinuclear cytoplasm and less abundantly in the nucleus. In clinical samples, we showed that like QKI5/6/7 proteins, QKI7b protein was also significantly downregulated in most human colorectal cancer tissues. These antibodies, therefore, might be useful in future functional studies of QKI7b.
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19
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Radomska KJ, Halvardson J, Reinius B, Lindholm Carlström E, Emilsson L, Feuk L, Jazin E. RNA-binding protein QKI regulates Glial fibrillary acidic protein expression in human astrocytes. Hum Mol Genet 2013; 22:1373-82. [PMID: 23321059 DOI: 10.1093/hmg/dds553] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Linkage, association and expression studies previously pointed to the human QKI, KH domain containing, RNA-binding (QKI) as a candidate gene for schizophrenia. Functional studies of the mouse orthologue Qk focused mainly on its role in oligodendrocyte development and myelination, while its function in astroglia remained unexplored. Here, we show that QKI is highly expressed in human primary astrocytes and that its splice forms encode proteins targeting different subcellular localizations. Uncovering the role of QKI in astrocytes is of interest in light of growing evidence implicating astrocyte dysfunction in the pathogenesis of several disorders of the central nervous system. We selectively silenced QKI splice variants in human primary astrocytes and used RNA sequencing to identify differential expression and splice variant composition at the genome-wide level. We found that an mRNA expression of Glial fibrillary acidic protein (GFAP), encoding a major component of astrocyte intermediate filaments, was down-regulated after QKI7 splice variant silencing. Moreover, we identified a potential QKI-binding site within the 3' untranslated region of human GFAP. This sequence was not conserved between mice and humans, raising the possibility that GFAP is a target for QKI in humans but not rodents. Haloperidol treatment of primary astrocytes resulted in coordinated increases in QKI7 and GFAP expression. Taken together, our results provide the first link between QKI and GFAP, two genes with alterations previously observed independently in schizophrenic patients. Our findings for QKI, together with its well-known role in myelination, suggest that QKI is a hub regulator of glia function in humans.
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Affiliation(s)
- Katarzyna J Radomska
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala,Sweden
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20
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Loss of p53 in quaking viable mice leads to Purkinje cell defects and reduced survival. Sci Rep 2011; 1:84. [PMID: 22355603 PMCID: PMC3239166 DOI: 10.1038/srep00084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 08/18/2011] [Indexed: 11/08/2022] Open
Abstract
The qk(v) mutation is a one megabase deletion resulting in abnormal expression of the qkI gene. qk(v) mice exhibit hypomyelination of the central nervous system and display rapid tremors and seizures as adults. The qkI locus on 6q26-27 has also been implicated as a candidate tumor suppressor gene as the qkI locus maps to a region of genetic instability in Glioblastoma Multiforme (GBM), an aggressive brain tumor of astrocytic lineage. As GBM frequently harbors mutations affecting p53, we crossbred qk(v) and p53 mutant mice to examine whether qk(v) mice on a p53(-/-) background have an increased incidence of GBM. qk(v) (/v); p53(-/-) mice had a reduced survival rate compared to p53(-/-) littermates, and the cause of death of the majority of the mice remains unknown. In addition, immunohistochemistry revealed Purkinje cell degeneration in the cerebellum. These results suggest that p53 and qkI are genetically linked for neuronal maintenance and survival.
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21
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Sánchez-Quiles V, Mora MI, Segura V, Greco A, Epstein AL, Foschini MG, Dayon L, Sanchez JC, Prieto J, Corrales FJ, Santamaría E. HSV-1 Cgal+ infection promotes quaking RNA binding protein production and induces nuclear-cytoplasmic shuttling of quaking I-5 isoform in human hepatoma cells. Mol Cell Proteomics 2011; 10:M111.009126. [PMID: 21467216 DOI: 10.1074/mcp.m111.009126] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Herpesvirus type 1 (HSV-1) based oncolytic vectors arise as a promising therapeutic alternative for neoplastic diseases including hepatocellular carcinoma. However, the mechanisms mediating the host cell response to such treatments are not completely known. It is well established that HSV-1 infection induces functional and structural alterations in the nucleus of the host cell. In the present work, we have used gel-based and shotgun proteomic strategies to elucidate the signaling pathways impaired in the nucleus of human hepatoma cells (Huh7) upon HSV-1 Cgal(+) infection. Both approaches allowed the identification of differential proteins suggesting impairment of cell functions involved in many aspects of host-virus interaction such as transcription regulation, mRNA processing, and mRNA splicing. Based on our proteomic data and additional functional studies, cellular protein quaking content (QKI) increases 4 hours postinfection (hpi), when viral immediate-early genes such as ICP4 and ICP27 could be also detected. Depletion of QKI expression by small interfering RNA results in reduction of viral immediate-early protein levels, subsequent decrease in early and late viral protein content, and a reduction in the viral yield indicating that QKI directly interferes with viral replication. In particular, HSV-1 Cgal(+) induces a transient increase in quaking I-5 isoform (QKI-5) levels, in parallel with an enhancement of p27(Kip1) protein content. Moreover, immunofluorescence microscopy showed an early nuclear redistribution of QKI-5, shuttling from the nucleus to the cytosol and colocalizing with nectin-1 in cell to cell contact regions at 16-24 hpi. This evidence sheds new light on mechanisms mediating hepatoma cell response to HSV-1 vectors highlighting QKI as a central molecular mediator.
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Affiliation(s)
- Virginia Sánchez-Quiles
- Division of Hepatology and Gene Therapy, Centre for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
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24
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Justice MJ, Hirschi KK. The role of quaking in mammalian embryonic development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 693:82-92. [PMID: 21189687 DOI: 10.1007/978-1-4419-7005-3_6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Functional studies of the mouse quaking gene (Qk) have focused on its role in the postnatal central nervous system during myelination. However, the death of the majority of homozygous mouse quaking alleles revealed that quaking has a critical role in embryonic development prior to the start of myelination. Surprisingly, the lethal alleles revealed that quaking has a function in embryonic blood vessel formation and remodeling. Further studies ofthe extraembryonic yolk sac showed that Qk regulates visceral endoderm differentiated function at the cellular level, including the local synthesis of retinoic acid (RA), which then exerts paracrine control of endothelial cells within adjacent mesoderm. Endoderm-derived RA regulates proliferation of endothelial cells and extracellular matrix (ECM) production, which in a reciprocal manner, modulates visceral endoderm survival and function. Although exogenous RA can rescue endothelial cell growth control and ECM production in mutants carrying a lethal mutation, which lack functional Qk, neither visceral endoderm function nor vascular remodeling is restored. Thus, Qk also regulates cell autonomous functions of visceral endoderm that are critical for vascular remodeling. Interestingly, quaking is highly expressed during normal cardiac development, particularly in the outflow tract, suggesting potentially unique functions in the developing heart. Together, the work on Qk in mammalian embryos reveals an essential, yet under appreciated, role in cardiovascular development. This suggests that certain functions may remain conserved in the early embryo throughout the evolution of nonvertebrate and vertebrate organisms and that additional roles for quaking remain to be discovered.
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Affiliation(s)
- Monica J Justice
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza MS227, R804, Houston, Texas 77030, USA.
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25
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Bockbrader K, Feng Y. Essential function, sophisticated regulation and pathological impact of the selective RNA-binding protein QKI in CNS myelin development. FUTURE NEUROLOGY 2008; 3:655-668. [PMID: 19727426 DOI: 10.2217/14796708.3.6.655] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The selective RNA-binding protein QKI play a key role in advancing oligodendrocyte-dependent myelination, which is essential for the function and development of the CNS. The emerging evidence that QKI abnormalities are associated with schizophrenia and may underlie myelin impairment in this devastating disease has greatly increased interest in understanding the function of QKI. Despite the discovery of the biochemical basis for QKI-RNA interaction, a comprehensive model is currently missing regarding how QKI regulates its mRNA ligands to promote normal myelinogenesis and how deficiency of the QKI pathway is involved in the pathogenesis of human diseases that affect CNS myelin. In this review, we will focus on the role of QKI in regulating distinct mRNA targets at critical developmental steps to promote oligodendrocyte differentiation and myelin formation. In addition, we will discuss molecular mechanisms that control QKI expression and activity during normal myelinogenesis as well as the pathological impact of QKI deficiency in dysmyelination mutant animals and in human myelin disorders.
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Affiliation(s)
- Katrina Bockbrader
- Department of Pharmacology, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA, Tel.: +1 404 727 0351, ,
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26
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Dobson NR, Zhou YX, Flint NC, Armstrong RC. Musashi1 RNA-binding protein regulates oligodendrocyte lineage cell differentiation and survival. Glia 2008; 56:318-30. [PMID: 18098125 PMCID: PMC2663423 DOI: 10.1002/glia.20615] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Expression of Musashi1 (Msi1), an evolutionarily conserved RNA‐binding protein, in neural stem cells of the subventricular zone in the postnatal and adult CNS indicates a potential role in the generation of oligodendrocytes. We now show Msi1 expression in a subset of oligodendrocyte progenitor (OP) cells in white matter areas temporally and spatially associated with oligodendrogenesis in the postnatal CNS. Msi1 function was evaluated by infection of OP cells with retroviral transduction of Msi1 or knockdown of endogenous Msi1. Retroviral expression of Msi1 significantly reduced the proportion of mature oligodendrocytes generated from OP cells in vitro and in vivo during myelination. Msi1 transduction also promoted OP survival, particularly under conditions of challenge from oxidative stress, while Msi1 siRNA knockdown resulted in dramatic OP cell death. Furthermore, in experimental demyelination Msi1 expression was increased among cells associated with lesions, including OP cells, indicating a potential role in the generation of remyelinating oligodendrocytes. © 2007 Wiley‐Liss, Inc.
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Affiliation(s)
- Nicole R Dobson
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
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27
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Chénard CA, Richard S. New implications for the QUAKING RNA binding protein in human disease. J Neurosci Res 2008; 86:233-42. [PMID: 17787018 DOI: 10.1002/jnr.21485] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The use of spontaneously occurring mouse models has proved to be a valuable tool throughout the years to delineate the signals required for nervous system development. This is especially true in the field of myelin biology, with a large number of different models available. The quaking viable mouse models dysmyelination in the nervous system and links the QUAKING RNA binding proteins to myelination and cell fate decisions. In this Mini-Review, we highlight the biological functions attributed to this KH-type RNA binding protein and the recent achievements linking it to human disorders.
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Affiliation(s)
- Carol Anne Chénard
- Terry Fox Molecular Oncology Group, Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research and Department of Oncology, McGill University, Montréal, Québec, Canada
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Lauriat TL, Shiue L, Haroutunian V, Verbitsky M, Ares M, Ospina L, McInnes LA. Developmental expression profile ofquaking, a candidate gene for schizophrenia, and its target genes in human prefrontal cortex and hippocampus shows regional specificity. J Neurosci Res 2008; 86:785-96. [DOI: 10.1002/jnr.21534] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Chen Y, Tian D, Ku L, Osterhout DJ, Feng Y. The selective RNA-binding protein quaking I (QKI) is necessary and sufficient for promoting oligodendroglia differentiation. J Biol Chem 2007; 282:23553-60. [PMID: 17575274 DOI: 10.1074/jbc.m702045200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Quaking I (QKI) is a selective RNA-binding protein essential for myelination of the central nervous system. Three QKI isoforms with distinct C termini and subcellular localization, namely QKI-5, QKI-6, and QKI-7, are expressed in oligodendroglia progenitor cells (OPCs) prior to the initiation of myelin formation and implicated in promoting oligodendrocyte lineage development. However, the functional requirement for each QKI isoform and the mechanisms by which QKI isoforms govern OPC development still remain elusive. We report here that exogenous expression of each QKI isoform is sufficient to enhance differentiation of OPCs with different efficiency, which is abolished by a point mutation that abrogates the RNA binding activity of QKI. Reciprocally, small interfering RNA-mediated QKI knockdown blocks OPC differentiation, which can be partly rescued by QKI-5 and QKI-6 but not by QKI-7, indicating the differential requirement of QKI isoform function in advancing OPC differentiation. Furthermore, we found that abrogation of OPC differentiation, as a result of QKI deficiency, is not due to altered proliferation capacity or cell cycle progression. These results indicate that QKI isoforms are necessary and sufficient for promoting OPC development, which must involve direct influence of QKI on differentiation/maturation of OPCs independent of cell cycle exit, likely via regulating the expression of the target mRNAs of QKI that support OPC differentiation.
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Affiliation(s)
- Yuntao Chen
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Zhao L, Ku L, Chen Y, Xia M, LoPresti P, Feng Y. QKI binds MAP1B mRNA and enhances MAP1B expression during oligodendrocyte development. Mol Biol Cell 2006; 17:4179-86. [PMID: 16855020 PMCID: PMC1635361 DOI: 10.1091/mbc.e06-04-0355] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Microtubule-associated protein 1B (MAP1B) is essential for neural development. Besides the abundant expression in neurons, MAP1B recently was found in myelinating oligodendroglia. Moreover, MAP1B deficiency causes delayed myelin development, suggesting the functional importance of MAP1B in oligodendroglia. However, molecular mechanisms that control MAP1B expression in oligodendroglia remain elusive. We report here that MAP1B mRNA is markedly up-regulated in the oligodendroglia cell line CG4 upon induced differentiation, leading to elevated MAP1B protein production. A coordinated regulation of homeoprotein transcription factors was observed during CG4 cell differentiation, which recapitulates the regulation in neurons that promotes MAP1B transcription. Hence, transcriptional regulation of MAP1B appears to be a common mechanism in both neurons and oligodendroglia. In addition, we found posttranscriptional regulation of MAP1B mRNA by the selective RNA-binding protein QKI in oligodendroglia. The 3'UTR of MAP1B mRNA interacts with QKI, and oligodendroglia-specific QKI-deficiency in the quakingviable mutant mice resulted in reduced MAP1B mRNA expression. Moreover, RNAi-mediated QKI-knockdown caused destabilization of the MAP1B mRNA in CG4 cells. Furthermore, forced expression of exogenous QKI was sufficient for promoting MAP1B expression. Because QKI is absent in neurons, QKI-dependent stabilization of MAP1B mRNA provides a novel mechanism for advancing MAP1B expression specifically in oligodendroglia during brain development.
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Affiliation(s)
- Lixia Zhao
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | - Li Ku
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | - Yuntao Chen
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | - Mingjing Xia
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | | | - Yue Feng
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
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31
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Dapper JD, Justice MJ. Defining the breakpoints of the quaking(viable) mouse mutation reveals a duplication from a Parkin intron. Mov Disord 2006; 20:1369-74. [PMID: 16001410 DOI: 10.1002/mds.20595] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The quakingviable (qkv) mutant mouse shows a recessive neurological phenotype that includes central nervous system (CNS) dysmyelination, seizures, and tremor associated with voluntary movement. The molecular defect of qkv has been previously reported to be a spontaneous approximately 1 megabase (Mb) deletion in the proximal region of mouse chromosome 17 that occurred in the DBA mouse strain more than four decades ago. The mutation has recently been shown to affect three genes in the region: Quaking (qk), Parkin-coregulated gene (Pacrg), and Parkin. Here we determine the exact deletion breakpoints and demonstrate that the mutation is not just comprised of a approximately 1.1 Mb deletion, but also harbors a small 163 bp duplication fragment between the deletion breakpoints. Although the distal deletion breakpoint is within the fifth intron of the mouse Parkin gene, the duplicated sequence is derived from the sixth Parkin intron and shows positive transcriptional activity on a reporter gene in vitro. This complexity provides insight into a well-studied neurological mutant and may have a role in affecting the phenotype observed.
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Affiliation(s)
- Jason D Dapper
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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32
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Urano Y, Iiduka M, Sugiyama A, Akiyama H, Uzawa K, Matsumoto G, Kawasaki Y, Tashiro F. Involvement of the mouse Prp19 gene in neuronal/astroglial cell fate decisions. J Biol Chem 2005; 281:7498-514. [PMID: 16352598 DOI: 10.1074/jbc.m510881200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molecular mechanisms involved in neuronal/astroglial cell fate decisions during the development of the mammalian central nervous system are poorly understood. Here, we report that PRP19beta, a splice variant of mouse PRP19alpha corresponding to the yeast PRP19 protein, can function as a neuron-astroglial switch during the retinoic acid-primed neural differentiation of P19 cells. The beta-variant possesses an additional 19 amino acid residues in-frame in the N-terminal region of the alpha-variant. The forced expression of the alpha-variant RNA caused the down-regulation of oct-3/4 and nanog mRNA expression during the 12-48 h of the late-early stages of neural differentiation and was sufficient to convert P19 cells into neurons (but not glial cells) when the cells were cultured in aggregated form without retinoic acid. In contrast, the forced expression of the beta-variant RNA suppressed neuronal differentiation and conversely stimulated astroglial cell differentiation in retinoic acid-primed P19 cells. Based on yeast two-hybrid screening, cyclophilin A was identified as a specific binding partner of the beta-variant. Luciferase reporter assay mediated by the oct-3/4 promoter revealed that cyclophilin A could act as a transcriptional activator and that its activity was suppressed by the beta-variant, suggesting that cyclophilin A takes part in the induction of oct-3/4 gene expression, which might lead to neuroectodermal otx2 expression within 12 h of the immediate-early stages of retinoic acid-primed neural differentiation. These results show that the alpha-variant gene plays a pivotal role in neural differentiation and that the beta-variant participates in neuronal/astroglial cell fate decisions.
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MESH Headings
- Alternative Splicing
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Carrier Proteins/physiology
- Cell Differentiation
- Cell Line
- Cell Lineage
- Cells, Cultured
- Chromatin Immunoprecipitation
- Chromatography, Gel
- Cloning, Molecular
- Cyclophilin A/chemistry
- DNA Primers/chemistry
- DNA Repair Enzymes
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Down-Regulation
- Genetic Vectors
- Green Fluorescent Proteins/metabolism
- Immunoprecipitation
- Luciferases/metabolism
- Mice
- Mice, Inbred ICR
- Models, Biological
- Molecular Sequence Data
- Neuroglia/metabolism
- Neurons/metabolism
- Nuclear Proteins
- Oligonucleotides/chemistry
- Promoter Regions, Genetic
- Protein Binding
- Protein Structure, Tertiary
- RNA/chemistry
- RNA/metabolism
- RNA Splicing Factors
- RNA, Messenger/metabolism
- Rats
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Spliceosomes/metabolism
- Time Factors
- Tissue Distribution
- Two-Hybrid System Techniques
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Affiliation(s)
- Yumiko Urano
- Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Yamazaki, Noda-shi, Chiba 270-8510, Japan
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Noveroske JK, Hardy R, Dapper JD, Vogel H, Justice MJ. A new ENU-induced allele of mouse quaking causes severe CNS dysmyelination. Mamm Genome 2005; 16:672-82. [PMID: 16245024 DOI: 10.1007/s00335-005-0035-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Accepted: 06/01/2005] [Indexed: 11/24/2022]
Abstract
The mutant allelic series of the mouse quaking gene consists of the spontaneous quaking(viable) (qk(v)) allele, which is homozygous viable with a dysmyelination phenotype, and four ENU-induced alleles (qk(kt 1), qk(k2), qk(kt3/4), and qk(l-1)), which are homozygous embryonic lethal. Here we report the isolation of qk(e5), the first ENU-induced viable allele of quaking. Unlike qk(v)/qk(v), qk(e5)/qk(e5) animals have early-onset seizures, severe ataxia, and a dramatically reduced lifespan. Ultrastructural analysis of qk(e5)/qk(e5) brains reveals severe dysmyelination when compared with both wild-type and qk(v)/qk(v) brains. In addition, Calbindin detection in young adult qk(e5)/qk(e5) mice reveals Purkinje cell axonal swellings indicative of neurodegeneration , which is not seen in young adult qk(v)/qk(v) mice. Although the molecular defect in the qk(e5) allele is not evident by sequencing, protein expression studies show that qk(e5)/qk(e5) postnatal oligodendrocytes lack the QKI-6 and QKI-7 isoforms and have reduced QKI-5 levels. The oligodendrocyte developmental markers PDGF alpha R, NG 2, O4, CNP, and MBP are also present in the qk(e5)/qk(e5) postnatal brain although CNP and MBP levels are considerably reduced. Because the qk(v) allele is a large deletion that affects the expression of three genes, the new neurologic qk(e5) allele is an important addition to this allelic series.
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Affiliation(s)
- Janice K Noveroske
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, S413, Houston, Texas 77030, USA
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Lakiza O, Frater L, Yoo Y, Villavicencio E, Walterhouse D, Goodwin EB, Iannaccone P. STAR proteins quaking-6 and GLD-1 regulate translation of the homologues GLI1 and tra-1 through a conserved RNA 3'UTR-based mechanism. Dev Biol 2005; 287:98-110. [PMID: 16198329 DOI: 10.1016/j.ydbio.2005.08.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Revised: 08/23/2005] [Accepted: 08/24/2005] [Indexed: 01/13/2023]
Abstract
The binding of the STAR protein GLD-1 to an element in the tra-2 3' untranslated region (3'UTR), called the TGE (tra GLI element), represses tra-2 translation, allowing for hermaphrodite spermatogenesis in Caenorhabditis elegans. GLD-1 is a member of the STAR family that includes the mammalian quaking (Qk) proteins. Here, we show that the 3'UTR of the nematode homologue of GLI1, called tra-1, also contains a TGE, through which translation is regulated by GLD-1. We find that GLD-1 activity is required for proper TRA-1 protein expression in hermaphrodites. RNA gel shift assays show that GLD-1 binds the predicted sites. Using reporter transgenes, we show that the human GLI1 (hGLI1) 3'UTR controls translation in the mouse embryo. We demonstrate that the addition of the mouse QK isoform-6 (QKI-6) protein to a mammalian cell line that lacks QKI-6 can confer regulation on reporter and GLI1 mRNAs in a TGE-specific manner, and reduction of QKI-6 activity with siRNA disrupts translational control. Further, siRNA knockdown of QKI-6 increases the activity of a reporter transgene that monitors the transcriptional activity of mouse Gli1 (mGli1) and increases mouse Gli1 protein. We show by immunoprecipitation that QKI-6 antibody specifically co-purifies TGE-containing mRNAs in ribonucleoproteins. Thus, we find that the mouse QKI-6 protein acts through the mGli1 and hGLI1 RNAs to repress translation. Our results suggest that STAR family-dependent translational control of GLI mRNAs is ancient, and that it existed before the division of nematodes and mammals.
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Affiliation(s)
- Olga Lakiza
- Department of Pediatrics, Northwestern University Feinberg School of Medicine and Children's Memorial Research Center, Chicago, IL 60614, USA
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35
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Galarneau A, Richard S. Target RNA motif and target mRNAs of the Quaking STAR protein. Nat Struct Mol Biol 2005; 12:691-8. [PMID: 16041388 DOI: 10.1038/nsmb963] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Accepted: 06/20/2005] [Indexed: 11/08/2022]
Abstract
Quaking viable (Qk(v)) mice have developmental defects that result in their characteristic tremor. The quaking (Qk) locus expresses alternatively spliced RNA-binding proteins belonging to the STAR family. To characterize the RNA binding specificity of the QKI proteins, we selected for RNA species that bound QKI from random pools of RNAs and defined the QKI response element (QRE) as a bipartite consensus sequence NACUAAY-N(1-20)-UAAY. A bioinformatic analysis using the QRE identified the three known RNA targets of QKI and 1,430 new putative mRNA targets, of which 23 were validated in vivo. A large proportion of the mRNAs are implicated in development and cell differentiation, as predicted from the phenotype of the Qk(v) mice. In addition, 24% are implicated in cell growth and/or maintenance, suggesting a role for QKI in cancer.
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Affiliation(s)
- André Galarneau
- Terry Fox Molecular Oncology Group, Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Department of Oncology, McGill University, Montréal, Québec, Canada, H3T 1E2
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36
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Larocque D, Galarneau A, Liu HN, Scott M, Almazan G, Richard S. Protection of p27Kip1 mRNA by quaking RNA binding proteins promotes oligodendrocyte differentiation. Nat Neurosci 2004; 8:27-33. [PMID: 15568022 DOI: 10.1038/nn1359] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Accepted: 09/16/2004] [Indexed: 11/09/2022]
Abstract
The quaking (Qk) locus expresses a family of RNA binding proteins, and the expression of several alternatively spliced isoforms coincides with the development of oligodendrocytes and the onset of myelination. Quaking viable (Qk(v)) mice harboring an autosomal recessive mutation in this locus have uncompacted myelin in the central nervous system owing to the inability of oligodendrocytes to properly mature. Here we show that the expression of two QKI isoforms, absent from oligodendrocytes of Qk(v) mice, induces cell cycle arrest of primary rat oligodendrocyte progenitor cells and differentiation into oligodendrocytes. Injection of retroviruses expressing QKI into the telencephalon of mouse embryos induced differentiation and migration of multipotential neural progenitor cells into mature oligodendrocytes localized in the corpus callosum. The mRNA encoding the cyclin-dependent kinase (CDK)-inhibitor p27(Kip1) was bound and stabilized by QKI, leading to an increased accumulation of p27(Kip1) protein in oligodendrocytes. Our findings demonstrate that QKI is upstream of p27(Kip1) during oligodendrocyte differentiation.
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Affiliation(s)
- Daniel Larocque
- Terry Fox Molecular Oncology Group and the Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
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37
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Ryder SP, Williamson JR. Specificity of the STAR/GSG domain protein Qk1: implications for the regulation of myelination. RNA (NEW YORK, N.Y.) 2004; 10:1449-58. [PMID: 15273320 PMCID: PMC1370631 DOI: 10.1261/rna.7780504] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Inadequate formation and maintenance of myelin is the basis for several neurodegenerative disorders, including leukodystrophy and multiple sclerosis. In mice, oligodendrocyte differentiation and subsequent formation of myelin requires the Quaking gene. Mutation of this gene leads to embryonic lethality or to a trembling phenotype characteristic of dysmyelination. Quaking encodes Qk1, a member of the highly conserved STAR/GSG family of RNA-binding proteins that function as master developmental regulators in higher eukaryotes. Qk1 has been implicated in the regulation of alternative splicing, stability, and translation control of mRNAs that code for myelin structural components in glial cells. We have used quantitative gel mobility shift and fluorescence polarization assays to define the nucleotide sequence specificity of the Qk1 STAR/GSG domain, and to probe the interaction between Qk1 and the 3'-untranslated region (UTR) of myelin basic protein (MBP) mRNA. The results show that Qk1 recognizes a hexanucleotide consensus element that is similar although not identical to the specificity determinant recognized by the Caenorhabditis elegans STAR/GSG protein GLD-1. Several consensus sites are present in the 3'-UTR of MBP mRNA. The highest affinity site is located within the RNA localization region, suggesting a possible role for Qk1 in restricting MBP mRNA to the myelin compartment.
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Affiliation(s)
- Sean P Ryder
- Department of Molecular Biology, The Scripps Research Institute, Mail Stop MB-33, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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38
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Le Saux F, Besson MJ, Maurin Y. Abnormal postnatal ontogeny of the locus coeruleus in the epileptic mutant mouse quaking. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2002; 136:197-205. [PMID: 12101037 DOI: 10.1016/s0165-3806(02)00386-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The tonic-clonic convulsions of the quaking mutant mice have been shown to be associated with the hyperplasia of the nucleus locus coeruleus, the origin of most brain noradrenergic neurons. In the present study, the postnatal ontogeny of the locus coeruleus has been studied by tyrosine hydroxylase immunolabeling in the mutant mice quaking and their controls at postnatal days 1, 30 and 90. In the control mice, the number of immunoreactive neuronal cell bodies increased significantly in the rostral half of the locus coeruleus between birth and postnatal day 30, while it decreased significantly in the caudal half between birth and adulthood. Thus, during postnatal maturation, the distribution of locus coeruleus neurons was shifted in the rostral direction. In the quaking mutant mice, while the increase of immunolabeling between birth and postnatal day 30 was observed in the rostral half of the locus coeruleus, no diminution could be found in the caudal half between birth and adulthood. As a result, the rostral shift of tyrosine hydroxylase immunoreactivity was not observed. Consequently, in adult mice, the caudal part of the mutants locus coeruleus appeared to contain significantly more neurons than the corresponding region in the controls. These results indicate that the hyperplasia of the locus coeruleus of the quaking mice that we had previously reported results from an alteration of the postnatal maturation of this nucleus. This developmental abnormality might be a primary determinant of the inherited epilepsy of the quaking mutant mice.
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Affiliation(s)
- Françoise Le Saux
- INSERM U 495 Hôpital de la Salpêtrière, 47 Bld de l'Hopital, 75651 Paris Cedex 13, France
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39
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Perrone-Bizzozero N, Bolognani F. Role of HuD and other RNA-binding proteins in neural development and plasticity. J Neurosci Res 2002; 68:121-6. [PMID: 11948657 DOI: 10.1002/jnr.10175] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Transcription factors have traditionally been viewed as the main determinants of gene expression. Yet, in recent years it has become apparent that RNA-binding proteins also play a critical role in determining the levels of expression of a large number of genes. Once mRNAs are transcribed, RNA-binding proteins can control all subsequent steps in their function, from alternative splicing and translation to mRNA transport and stability. In the nervous system, a large number of genes are regulated post-transcriptionally via the interaction of their mRNAs with specific RNA-binding proteins. This type of regulation is particularly important in the control of the temporal and spatial pattern of gene expression during neural development. This review will discuss the function of the embryonic lethal abnormal vision (ELAV)/Hu family of nervous system-specific RNA-binding proteins, with a special emphasis on HuD, a member of this family that controls GAP-43 mRNA stability and expression. In addition, we will present recent findings on other neural RNA-binding proteins: the ribonucleoprotein K homology (KH)-domain proteins, Fragile X mental retardation protein (FMRP), quakinguiable protein (QKI), and Nova-1. Together with the ELAV/Hu family, these proteins are essential for proper neural development and in some cases for plasticity in the mature brain. The biological significance of these proteins is evident not only by their evolutionary conservation but also by the magnitude of problems arising from autoimmune reactions against them or from mutations affecting their expression or function.
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Affiliation(s)
- Nora Perrone-Bizzozero
- Department of Neurosciences, University of New Mexico School of Medicine, 915 Camino de Salud NE, BMSB Rm. 145, Albuquerque, NM 87131-5223, USA.
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40
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Noveroske JK, Lai L, Gaussin V, Northrop JL, Nakamura H, Hirschi KK, Justice MJ. Quaking is essential for blood vessel development. Genesis 2002; 32:218-30. [PMID: 11892011 DOI: 10.1002/gene.10060] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
For nearly 40 years functional studies of the mouse quaking gene (qkI) have focused on its role in the postnatal central nervous system during myelination. However, the homozygous lethality of a number of ENU-induced alleles reveals that quaking has a critical role in embryonic development prior to the start of myelination. In this article, we show that quaking has a previously unsuspected and essential role in blood vessel development. Interestingly, we found that quaking, a nonsecreted protein, is expressed in the yolk sac endoderm, adjacent to the mesodermal site of developing blood islands, where the differentiation of blood and endothelial cells first occurs. Antibodies against PE-CAM-1, TIE-2 and SM-alpha-actin reveal that embryos homozygous for the qk(k2) allele have defective yolk sac vascular remodeling and abnormal vessels in the embryo proper at midgestation, coinciding with the timing of embryonic death. However, these mutants exhibit normal expression of Nkx2.5 and alpha-sarcomeric actin, indicating that cardiac muscle differentiation was normal. Further, they had normal embryonic heart rates in culture, suggesting that cardiac function was not compromised at this stage of embryonic development. Together, these results suggest that quaking plays an essential role in vascular development and that the blood vessel defects are the cause of embryonic death.
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Affiliation(s)
- Janice K Noveroske
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
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41
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Levers TE, Edgar JM, Price DJ. The fates of cells generated at the end of neurogenesis in developing mouse cortex. JOURNAL OF NEUROBIOLOGY 2001; 48:265-77. [PMID: 11500840 DOI: 10.1002/neu.1056] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Most cerebral cortical neurons are generated between embryonic days 11 and 17 (E11-17) in the mouse. Radial glial cells also proliferate during this time; they can give rise to neurons and many later transform into astrocytes. It is thought that most glial cells comprising the mature cortex, including additional astrocytes, are generated after neurogenesis is complete. Little is known about the cellular events that occur during the transition from the phase dominated by neurogenesis to that of gliogenesis. We labeled cells generated on E18 and E19 and the day of birth (P0) with bromodeoxyuridine and followed their fates over the following 20 days. Our results showed that, on E18-P0, cells divide throughout the ventricular zone, subventricular zone, intermediate zone, and to a lesser extent, the developing cortical plate, whereas neuronal precursors generated prior to E18 divide in the ventricular zone. Our results indicated that 30-40% of cells dividing on E18 give rise to neurons that migrate to the most superficial part of the cortex. The rest of the cells dividing on E18 and 76-94% of cells generated on E19 and P0 express the QKI RNA-binding protein, indicating that they either remain as multipotential progenitors or develop into glial cells. Nine to fifteen percent of cells generated on E18-P0 become glial fibrillary acidic protein-positive astrocytes. Many E19 and P0 labeled cells disappear between 2 and 20 days postlabeling, probably because they continue to divide. We conclude that the population of cells produced at the end of cortical neurogenesis is heterogeneous and comprises postmitotic neurons, glia (including astrocytes), and possibly multipotential progenitors.
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Affiliation(s)
- T E Levers
- Genes and Development Group, University of Edinburgh Medical School, United Kingdom
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42
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Abstract
We have examined the gene expression of two radial glia intermediate filament proteins, transitin and vimentin, in the developing chick CNS. Despite global similarities in their mRNA distributions, marked regional differences are observed. Most notably, we show that transitin mRNA is localized along radial glial processes and is localized to radial glia endfeet, whereas vimentin mRNA is not localized in radial glia. Localization of transitin mRNA is best shown in the diencephalic radial glia, as well as cerebellar Bergmann glia. In addition, in the early embryonic optic tectum, telencephalon, and retina, transitin mRNA is highly localized to radial glia endfeet, which is suggestive of its transport in these cells. These in vivo demonstrations of transitin mRNA localization are confirmed by in situ hybridization analysis of cultured chick brain radial glia, which demonstrates the presence of granular staining for transitin mRNA in glial processes. Transitin mRNA distribution in developing muscle also shows a highly regulated expression pattern, especially along the Z-lines of myofibrils. As further support for the transport and localization of transitin mRNA in radial glia and muscle, we have identified a consensus RNA transport signal in transitin mRNA that is absent from vimentin. These data suggest that the local regulation of transitin protein synthesis may contribute to its function as an intermediate filament protein in radial glia.
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Affiliation(s)
- J A Lee
- Neurobiotechnology Center and Department of Neuroscience, The Ohio State University, Columbus, Ohio 43210, USA
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43
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Wu J, Zhou L, Tonissen K, Tee R, Artzt K. The quaking I-5 protein (QKI-5) has a novel nuclear localization signal and shuttles between the nucleus and the cytoplasm. J Biol Chem 1999; 274:29202-10. [PMID: 10506177 DOI: 10.1074/jbc.274.41.29202] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mouse quaking (qk) gene is essential in both myelination and early embryogenesis. Its product, QKI, is an RNA-binding protein belonging to a growing protein family called STAR (signal transduction and activator of RNA). All members have an approximately 200-amino acid STAR domain, which contains a single extended heteronuclear ribonucleoprotein K homologue domain flanked by two domains called QUA1 and QUA2. We found that QKI isoforms could associate with each other, while one of the lethal mutations qkI(kt4) with a single amino acid change in QUA1 domain, leads to a loss of QKI self-interaction. This suggests that the QUA1 domain is responsible for QKI dimerization. Three QKI isoforms have different carboxyl termini and different subcellular localization. Here, using GFP fusion protein, we identified a 7-amino acid novel nuclear localization sequence in the carboxyl terminus of QKI-5, which is conserved in a subclass of STAR proteins containing SAM68 and ETLE/T-STAR. Thus, we name this motif STAR-NLS. In addition, the effects of active transcription, RNA-binding and self-interaction on QKI-5 localization were analyzed. Furthermore, using an interspecies heterokaryon assay, we found that QKI-5, but not another STAR protein ETLE, shuttles between the nucleus and the cytoplasm, which suggests that QKI-5 functions in both cell compartments.
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Affiliation(s)
- J Wu
- Institute for Cellular and Molecular Biology, Department of Microbiology, University of Texas, Austin, Texas 78712-1064, USA
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44
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Rogister B, Ben-Hur T, Dubois-Dalcq M. From neural stem cells to myelinating oligodendrocytes. Mol Cell Neurosci 1999; 14:287-300. [PMID: 10588385 DOI: 10.1006/mcne.1999.0790] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The potential to generate oligodendrocytes progenitors (OP) from neural stem cells (NSCs) exists throughout the developing CNS. Yet, in the embryonic spinal cord, the oligodendrocyte phenotype is induced by sonic hedgehog in a restricted anterior region. In addition, neuregulins are emerging as potent regulators of early and late OP development. The ability to isolate and grow NSCs as well as glial-restricted progenitors has revealed that FGF2 and thyroid hormone favor an oligodendrocyte fate. Analysis of genetically modified mice showed that PDGF controls the migration and production of oligodendrocytes in vivo. Interplay between mitogens, thyroid hormone, and neurotransmitters may maintain the undifferentiated stage or result in OP growth arrest. Notch signaling by axons inhibits oligodendrocyte differentiation until neuronal signals--linked to electrical activity-trigger initiation of myelination. To repair myelin in adult CNS, multipotential neural precursors, rather than slowly cycling OP, appear the cells of choice to rapidly generate myelin-forming cells.
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Affiliation(s)
- B Rogister
- Department of Human Physiology, University of Liège, Belgium
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45
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Casaccia-Bonnefil P, Hardy RJ, Teng KK, Levine JM, Koff A, Chao MV. Loss of p27Kip1 function results in increased proliferative capacity of oligodendrocyte progenitors but unaltered timing of differentiation. Development 1999; 126:4027-37. [PMID: 10457012 DOI: 10.1242/dev.126.18.4027] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In many tissues, progenitor cells permanently withdraw from the cell cycle prior to commitment towards a differentiated phenotype. In the oligodendrocyte lineage a counting mechanism has been proposed, linking the number of cell divisions to growth arrest and differentiation. A direct prediction of this model is that an increase in the number of cell divisions would result in a delayed onset of differentiation. Since the cell cycle inhibitor p27Kip1 is an essential component of the machinery leading to oligodendrocyte progenitor growth arrest, we examined the temporal relationship between cell cycle withdrawal and expression of late differentiation markers in vivo, in mice carrying a targeted deletion in the p27Kip1 gene. Using bromodeoxyuridine to label proliferating cells, quaking (QKI) to identify embryonic glial progenitors, NG2 to identify neonatal oligodendrocyte progenitors, and myelin basic protein to label differentiated oligodendrocytes, we found an increased number of proliferating QKI- and NG2-positive cells in germinal zones of p27Kip1(−/−) mice at the peak of gliogenesis. However, no delay was observed in these mice in the appearance of the late differentiation marker myelin basic protein in the developing corpus callosum and cerebellum. Significantly, a decrease in cyclin E levels was observed in the brain of p27Kip1 null mice coincident with oligodendrocyte growth arrest. We conclude that two distinct modalities of growth arrest occur in the oligodendrocyte lineage: a p27Kip1-dependent mechanism of growth arrest affecting proliferation in early phases of gliogenesis, and a p27Kip1-independent event leading to withdrawal from the cell cycle and differentiation.
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Affiliation(s)
- P Casaccia-Bonnefil
- Molecular Neurobiology, Skirball Institute for Biomolecular Medicine at NYU Medical Center, New York, NY 10016, USA. . nyu.edu
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Wulf P, Suter U. Embryonic expression of epithelial membrane protein 1 in early neurons. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1999; 116:169-80. [PMID: 10521561 DOI: 10.1016/s0165-3806(99)00092-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Epithelial membrane protein 1 (EMP1) is a member of the peripheral myelin protein 22 (PMP22) family. This family is best known for the crucial contribution of PMP22 to the development and maintenance of the peripheral nervous system (PNS). PMP22 is widely expressed, with highest levels in myelinating Schwann cells, and mutations affecting the PMP22 gene lead to PNS-restricted neuropathies. We have investigated the spatio-temporal distribution of EMP1 and compared it to that of PMP22. We found that EMP1 and PMP22 mRNA are most conspicuously expressed in the prenatal mouse brain during neurogenesis. In the developing forebrain, we localized EMP1 mRNA and protein to the first set of neurons that are generated and leave the ventricular zone to form the preplate. Later in development, EMP1 was found in derivatives of the preplate, the marginal zone and the subplate. Reduced expression was observed in the newly generated cortical plate neurons. In other parts of the developing CNS and PNS, EMP1 was also detected in early neurons and along the initial fiber tracts. Furthermore, EMP1 was highly expressed by immature neurons in embryonal dorsal root ganglia-explant cultures and in neuroectodermal differentiated P19 cells. While PMP22 functions mainly in Schwann cell growth and differentiation, the spatio-temporal localization of EMP1 suggests a role in neuronal differentiation and neurite outgrowth.
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Affiliation(s)
- P Wulf
- Institute of Cell Biology, Department of Biology, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093, Zürich, Switzerland
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