1
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Finger DS, Williams AE, Holt VV, Ables ET. Novel roles for RNA binding proteins squid, hephaesteus, and Hrb27C in Drosophila oogenesis. Dev Dyn 2023; 252:415-428. [PMID: 36308715 PMCID: PMC9991940 DOI: 10.1002/dvdy.550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 09/30/2022] [Accepted: 10/16/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Reproductive capacity in many organisms is maintained by germline stem cells (GSCs). A complex regulatory network influences stem cell fate, including intrinsic factors, local signals, and hormonal and nutritional cues. Posttranscriptional regulatory mechanisms ensure proper cell fate transitions, promoting germ cell differentiation to oocytes. As essential RNA binding proteins with constitutive functions in RNA metabolism, heterogeneous nuclear ribonucleoproteins (hnRNPs) have been implicated in GSC function and axis specification during oocyte development. HnRNPs support biogenesis, localization, maturation, and translation of nascent transcripts. Whether and individual hnRNPs specifically regulate GSC function has yet to be explored. RESULTS We demonstrate that hnRNPs are expressed in distinct patterns in the Drosophila germarium. We show that three hnRNPs, squid, hephaestus, and Hrb27C are cell-autonomously required in GSCs for their maintenance. Although these hnRNPs do not impact adhesion of GSCs to adjacent cap cells, squid and hephaestus (but not Hrb27C) are necessary for proper bone morphogenetic protein signaling in GSCs. Moreover, Hrb27C promotes proper GSC proliferation, whereas hephaestus promotes cyst division. CONCLUSIONS We find that hnRNPs are independently and intrinsically required in GSCs for their maintenance in adults. Our results support the model that hnRNPs play unique roles in stem cells essential for their self-renewal and proliferation.
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Affiliation(s)
- Danielle S. Finger
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Anna E. Williams
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Vivian V. Holt
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Elizabeth T. Ables
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
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2
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Torres-Méndez A, Pop S, Bonnal S, Almudi I, Avola A, Roberts RJV, Paolantoni C, Alcaina-Caro A, Martín-Anduaga A, Haussmann IU, Morin V, Casares F, Soller M, Kadener S, Roignant JY, Prieto-Godino L, Irimia M. Parallel evolution of a splicing program controlling neuronal excitability in flies and mammals. SCIENCE ADVANCES 2022; 8:eabk0445. [PMID: 35089784 PMCID: PMC8797185 DOI: 10.1126/sciadv.abk0445] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 12/08/2021] [Indexed: 05/08/2023]
Abstract
Alternative splicing increases neuronal transcriptomic complexity throughout animal phylogeny. To delve into the mechanisms controlling the assembly and evolution of this regulatory layer, we characterized the neuronal microexon program in Drosophila and compared it with that of mammals. In nonvertebrate bilaterians, this splicing program is restricted to neurons by the posttranscriptional processing of the enhancer of microexons (eMIC) domain in Srrm234. In Drosophila, this processing is dependent on regulation by Elav/Fne. eMIC deficiency or misexpression leads to widespread neurological alterations largely emerging from impaired neuronal activity, as revealed by a combination of neuronal imaging experiments and cell type-specific rescues. These defects are associated with the genome-wide skipping of short neural exons, which are strongly enriched in ion channels. We found no overlap of eMIC-regulated exons between flies and mice, illustrating how ancient posttranscriptional programs can evolve independently in different phyla to affect distinct cellular modules while maintaining cell-type specificity.
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Affiliation(s)
- Antonio Torres-Méndez
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
- Francis Crick Institute, London, UK
| | | | - Sophie Bonnal
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - Isabel Almudi
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
- Department of Genetics, Microbiology and Statistics and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain
| | | | | | - Chiara Paolantoni
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Ana Alcaina-Caro
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
| | | | - Irmgard U. Haussmann
- Department of Life Science, School of Health Sciences, Birmingham City University, Birmingham B5 3TN, UK
| | - Violeta Morin
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Fernando Casares
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | | - Jean-Yves Roignant
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Staudingerweg 5, 55128 Mainz, Germany
| | | | - Manuel Irimia
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain
- ICREA, Barcelona, Spain
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3
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Dionne O, Corbin F. An "Omic" Overview of Fragile X Syndrome. BIOLOGY 2021; 10:433. [PMID: 34068266 PMCID: PMC8153138 DOI: 10.3390/biology10050433] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/01/2021] [Accepted: 05/08/2021] [Indexed: 01/16/2023]
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder associated with a wide range of cognitive, behavioral and medical problems. It arises from the silencing of the fragile X mental retardation 1 (FMR1) gene and, consequently, in the absence of its encoded protein, FMRP (fragile X mental retardation protein). FMRP is a ubiquitously expressed and multifunctional RNA-binding protein, primarily considered as a translational regulator. Pre-clinical studies of the past two decades have therefore focused on this function to relate FMRP's absence to the molecular mechanisms underlying FXS physiopathology. Based on these data, successful pharmacological strategies were developed to rescue fragile X phenotype in animal models. Unfortunately, these results did not translate into humans as clinical trials using same therapeutic approaches did not reach the expected outcomes. These failures highlight the need to put into perspective the different functions of FMRP in order to get a more comprehensive understanding of FXS pathophysiology. This work presents a review of FMRP's involvement on noteworthy molecular mechanisms that may ultimately contribute to various biochemical alterations composing the fragile X phenotype.
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Affiliation(s)
- Olivier Dionne
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke and Centre de Recherche du CHUS, CIUSSS de l’Estrie-CHUS, Sherbrooke, QC J1H 5H4, Canada;
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4
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Sternburg EL, Karginov FV. Global Approaches in Studying RNA-Binding Protein Interaction Networks. Trends Biochem Sci 2020; 45:593-603. [DOI: 10.1016/j.tibs.2020.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/28/2020] [Accepted: 03/09/2020] [Indexed: 12/24/2022]
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5
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Lang B, Armaos A, Tartaglia GG. RNAct: Protein-RNA interaction predictions for model organisms with supporting experimental data. Nucleic Acids Res 2020; 47:D601-D606. [PMID: 30445601 PMCID: PMC6324028 DOI: 10.1093/nar/gky967] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 10/11/2018] [Indexed: 01/15/2023] Open
Abstract
Protein-RNA interactions are implicated in a number of physiological roles as well as diseases, with molecular mechanisms ranging from defects in RNA splicing, localization and translation to the formation of aggregates. Currently, ∼1400 human proteins have experimental evidence of RNA-binding activity. However, only ∼250 of these proteins currently have experimental data on their target RNAs from various sequencing-based methods such as eCLIP. To bridge this gap, we used an established, computationally expensive protein-RNA interaction prediction method, catRAPID, to populate a large database, RNAct. RNAct allows easy lookup of known and predicted interactions and enables global views of the human, mouse and yeast protein-RNA interactomes, expanding them in a genome-wide manner far beyond experimental data (http://rnact.crg.eu).
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Affiliation(s)
- Benjamin Lang
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
| | - Alexandros Armaos
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
| | - Gian G Tartaglia
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), 23 Passeig Lluís Companys, Barcelona 08010, Spain.,Universitat Pompeu Fabra (UPF), Department of Experimental and Health Sciences, Barcelona 08003, Spain.,Department of Biology 'Charles Darwin', Sapienza University of Rome, P.le A. Moro 5, Rome 00185, Italy
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6
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Samuels TJ, Arava Y, Järvelin AI, Robertson F, Lee JY, Yang L, Yang CP, Lee T, Ish-Horowicz D, Davis I. Neuronal upregulation of Prospero protein is driven by alternative mRNA polyadenylation and Syncrip-mediated mRNA stabilisation. Biol Open 2020; 9:bio049684. [PMID: 32205310 PMCID: PMC7225087 DOI: 10.1242/bio.049684] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
During Drosophila and vertebrate brain development, the conserved transcription factor Prospero/Prox1 is an important regulator of the transition between proliferation and differentiation. Prospero level is low in neural stem cells and their immediate progeny, but is upregulated in larval neurons and it is unknown how this process is controlled. Here, we use single molecule fluorescent in situ hybridisation to show that larval neurons selectively transcribe a long prospero mRNA isoform containing a 15 kb 3' untranslated region, which is bound in the brain by the conserved RNA-binding protein Syncrip/hnRNPQ. Syncrip binding increases the stability of the long prospero mRNA isoform, which allows an upregulation of Prospero protein production. Adult flies selectively lacking the long prospero isoform show abnormal behaviour that could result from impaired locomotor or neurological activity. Our findings highlight a regulatory strategy involving alternative polyadenylation followed by differential post-transcriptional regulation.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Tamsin J Samuels
- Department of Biochemistry, The University of Oxford, Oxford, OX1 3QU, UK
| | - Yoav Arava
- Department of Biochemistry, The University of Oxford, Oxford, OX1 3QU, UK
- Department of Biology Technion, Haifa, 32000, Israel
| | - Aino I Järvelin
- Department of Biochemistry, The University of Oxford, Oxford, OX1 3QU, UK
| | | | - Jeffrey Y Lee
- Department of Biochemistry, The University of Oxford, Oxford, OX1 3QU, UK
| | - Lu Yang
- Department of Biochemistry, The University of Oxford, Oxford, OX1 3QU, UK
| | - Ching-Po Yang
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA, 20147 USA
| | - Tzumin Lee
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA, 20147 USA
| | - David Ish-Horowicz
- Department of Biochemistry, The University of Oxford, Oxford, OX1 3QU, UK
- MRC Laboratory for Molecular Cell Biology, University College, London, WC1E 6BT UK
| | - Ilan Davis
- Department of Biochemistry, The University of Oxford, Oxford, OX1 3QU, UK
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7
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UPF1 regulates the malignant biological behaviors of glioblastoma cells via enhancing the stability of Linc-00313. Cell Death Dis 2019; 10:629. [PMID: 31427569 PMCID: PMC6700115 DOI: 10.1038/s41419-019-1845-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/08/2019] [Accepted: 07/24/2019] [Indexed: 12/18/2022]
Abstract
There is growing evidence that the long non-coding RNAs(lncRNAs) play an important role in the biological behaviors of glioblastoma cells. In this study, we elucidated the function and possible effect and molecular mechanisms of lncRNA-Linc-00313 on the biological behaviors of glioblastoma cells as well as UPF1 function as a RNA-binding protein to enhance its stability. Here, we used qRT-PCR and western blot to measure the expression, cell Transfection to disrupt the expression of genes, cell viability analysis, quantization of apoptosis, cell migration, and invasion assays, Reporter vectors construction and luciferase assays to investigate the malignant biological behaviors of cells, human lncRNA microarrays, RNA-Immunoprecipitation, dual-luciferase gene reporter assay, half-life assay and chromatin immunoprecipitation to verify the binding sites, tumor xenograft implantation for in vivo experiment, SPSS 18.0 statistical software for data statistics. UPF1 and Linc-00313 were both upregulated in glioma tissues and cells. Knockdown of UPF1 or Linc-00313 significantly inhibited malignant biological behaviors of glioma cells by regulating miR-342-3p and miR-485-5p, which are downregulated and functioned as tumor suppressors in glioma. Furthermore, Linc-00313 could acted as a competing endogenous RNA(ceRNA) to regulate the expression of Zic4 by binding to miR-342-3p and miR-485-5p. Interestingly, Zic4 could bind to the promoters of UPF1 and Linc-00313 respectively and upregulate the expression of them. These results indicated that a positive-feedback loop was formed in the regulation of the biological behaviors of glioma cells. The study is the first to prove that the UPF1-Linc-00313-miR-342-3p/miR-485-5p-Zic4-SHCBP1 pathway forms a positive-feedback loop and regulates the biological behaviors of U87 and U251 cells, which might provide a new therapeutic target for glioma.
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8
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Ye W, Long Y, Ji G, Su Y, Ye P, Fu H, Wu X. Cluster analysis of replicated alternative polyadenylation data using canonical correlation analysis. BMC Genomics 2019; 20:75. [PMID: 30669970 PMCID: PMC6343338 DOI: 10.1186/s12864-019-5433-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 01/03/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Alternative polyadenylation (APA) has emerged as a pervasive mechanism that contributes to the transcriptome complexity and dynamics of gene regulation. The current tsunami of whole genome poly(A) site data from various conditions generated by 3' end sequencing provides a valuable data source for the study of APA-related gene expression. Cluster analysis is a powerful technique for investigating the association structure among genes, however, conventional gene clustering methods are not suitable for APA-related data as they fail to consider the information of poly(A) sites (e.g., location, abundance, number, etc.) within each gene or measure the association among poly(A) sites between two genes. RESULTS Here we proposed a computational framework, named PASCCA, for clustering genes from replicated or unreplicated poly(A) site data using canonical correlation analysis (CCA). PASCCA incorporates multiple layers of gene expression data from both the poly(A) site level and gene level and takes into account the number of replicates and the variability within each experimental group. Moreover, PASCCA characterizes poly(A) sites in various ways including the abundance and relative usage, which can exploit the advantages of 3' end deep sequencing in quantifying APA sites. Using both real and synthetic poly(A) site data sets, the cluster analysis demonstrates that PASCCA outperforms other widely-used distance measures under five performance metrics including connectivity, the Dunn index, average distance, average distance between means, and the biological homogeneity index. We also used PASCCA to infer APA-specific gene modules from recently published poly(A) site data of rice and discovered some distinct functional gene modules. We have made PASCCA an easy-to-use R package for APA-related gene expression analyses, including the characterization of poly(A) sites, quantification of association between genes, and clustering of genes. CONCLUSIONS By providing a better treatment of the noise inherent in repeated measurements and taking into account multiple layers of poly(A) site data, PASCCA could be a general tool for clustering and analyzing APA-specific gene expression data. PASCCA could be used to elucidate the dynamic interplay of genes and their APA sites among various biological conditions from emerging 3' end sequencing data to address the complex biological phenomenon.
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Affiliation(s)
- Wenbin Ye
- Department of Automation, Xiamen University, Xiamen, 361005, China.,Innovation Center for Cell Biology, Xiamen University, Xiamen, 361005, China
| | - Yuqi Long
- Department of Automation, Xiamen University, Xiamen, 361005, China.,Software Quality Testing Engineering Research Center, China Electronic Product Reliability and Environmental Testing Research Institute, Guangzhou, 510610, China
| | - Guoli Ji
- Department of Automation, Xiamen University, Xiamen, 361005, China.,Innovation Center for Cell Biology, Xiamen University, Xiamen, 361005, China
| | - Yaru Su
- College of Mathematics and Computer Science, Fuzhou University, Fuzhou, 350116, China
| | - Pengchao Ye
- Department of Automation, Xiamen University, Xiamen, 361005, China
| | - Hongjuan Fu
- Department of Automation, Xiamen University, Xiamen, 361005, China
| | - Xiaohui Wu
- Department of Automation, Xiamen University, Xiamen, 361005, China. .,Innovation Center for Cell Biology, Xiamen University, Xiamen, 361005, China.
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9
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Wang Q, Abruzzi KC, Rosbash M, Rio DC. Striking circadian neuron diversity and cycling of Drosophila alternative splicing. eLife 2018; 7:35618. [PMID: 29863472 PMCID: PMC6025963 DOI: 10.7554/elife.35618] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/31/2018] [Indexed: 11/13/2022] Open
Abstract
Although alternative pre-mRNA splicing (AS) significantly diversifies the neuronal proteome, the extent of AS is still unknown due in part to the large number of diverse cell types in the brain. To address this complexity issue, we used an annotation-free computational method to analyze and compare the AS profiles between small specific groups of Drosophila circadian neurons. The method, the Junction Usage Model (JUM), allows the comprehensive profiling of both known and novel AS events from specific RNA-seq libraries. The results show that many diverse and novel pre-mRNA isoforms are preferentially expressed in one class of clock neuron and also absent from the more standard Drosophila head RNA preparation. These AS events are enriched in potassium channels important for neuronal firing, and there are also cycling isoforms with no detectable underlying transcriptional oscillations. The results suggest massive AS regulation in the brain that is also likely important for circadian regulation.
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Affiliation(s)
- Qingqing Wang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Center for RNA Systems Biology (CRSB), University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, United States
| | - Katharine C Abruzzi
- Department of Biology, Howard Hughes Medical Institute, Brandeis University, Waltham, United States.,National Center for Behavior Genomics, Brandeis University, Waltham, United States
| | - Michael Rosbash
- Department of Biology, Howard Hughes Medical Institute, Brandeis University, Waltham, United States.,National Center for Behavior Genomics, Brandeis University, Waltham, United States
| | - Donald C Rio
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Center for RNA Systems Biology (CRSB), University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, United States
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10
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Dockendorff TC, Labrador M. The Fragile X Protein and Genome Function. Mol Neurobiol 2018; 56:711-721. [PMID: 29796988 DOI: 10.1007/s12035-018-1122-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/11/2018] [Indexed: 12/21/2022]
Abstract
The fragile X syndrome (FXS) arises from loss of expression or function of the FMR1 gene and is one of the most common monogenic forms of intellectual disability and autism. During the past two decades of FXS research, the fragile X mental retardation protein (FMRP) has been primarily characterized as a cytoplasmic RNA binding protein that facilitates transport of select RNA substrates through neural projections and regulation of translation within synaptic compartments, with the protein products of such mRNAs then modulating cognitive functions. However, the presence of a small fraction of FMRP in the nucleus has long been recognized. Accordingly, recent studies have uncovered several mechanisms or pathways by which FMRP influences nuclear gene expression and genome function. Some of these pathways appear to be independent of the classical role for FMRP as a regulator of translation and point to novel functions, including the possibility that FMRP directly participates in the DNA damage response and in the maintenance of genome stability. In this review, we highlight these advances and discuss how these new findings could contribute to our understanding of FMRP in brain development and function, the neural pathology of fragile X syndrome, and perhaps impact of future therapeutic considerations.
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Affiliation(s)
- Thomas C Dockendorff
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, 37996, USA.
| | - Mariano Labrador
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, 37996, USA.
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11
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Harvey RF, Smith TS, Mulroney T, Queiroz RML, Pizzinga M, Dezi V, Villenueva E, Ramakrishna M, Lilley KS, Willis AE. Trans-acting translational regulatory RNA binding proteins. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9:e1465. [PMID: 29341429 PMCID: PMC5947564 DOI: 10.1002/wrna.1465] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/31/2017] [Accepted: 12/04/2017] [Indexed: 12/13/2022]
Abstract
The canonical molecular machinery required for global mRNA translation and its control has been well defined, with distinct sets of proteins involved in the processes of translation initiation, elongation and termination. Additionally, noncanonical, trans-acting regulatory RNA-binding proteins (RBPs) are necessary to provide mRNA-specific translation, and these interact with 5' and 3' untranslated regions and coding regions of mRNA to regulate ribosome recruitment and transit. Recently it has also been demonstrated that trans-acting ribosomal proteins direct the translation of specific mRNAs. Importantly, it has been shown that subsets of RBPs often work in concert, forming distinct regulatory complexes upon different cellular perturbation, creating an RBP combinatorial code, which through the translation of specific subsets of mRNAs, dictate cell fate. With the development of new methodologies, a plethora of novel RNA binding proteins have recently been identified, although the function of many of these proteins within mRNA translation is unknown. In this review we will discuss these methodologies and their shortcomings when applied to the study of translation, which need to be addressed to enable a better understanding of trans-acting translational regulatory proteins. Moreover, we discuss the protein domains that are responsible for RNA binding as well as the RNA motifs to which they bind, and the role of trans-acting ribosomal proteins in directing the translation of specific mRNAs. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes Translation > Translation Regulation Translation > Translation Mechanisms.
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Affiliation(s)
| | - Tom S. Smith
- Cambridge Centre for Proteomics, Department of BiochemistryUniversity of CambridgeCambridgeUK
| | | | - Rayner M. L. Queiroz
- Cambridge Centre for Proteomics, Department of BiochemistryUniversity of CambridgeCambridgeUK
| | | | | | - Eneko Villenueva
- Cambridge Centre for Proteomics, Department of BiochemistryUniversity of CambridgeCambridgeUK
| | | | - Kathryn S. Lilley
- Cambridge Centre for Proteomics, Department of BiochemistryUniversity of CambridgeCambridgeUK
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12
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Abstract
We developed a predictive, stable, and interpretable tool: the iterative random forest algorithm (iRF). iRF discovers high-order interactions among biomolecules with the same order of computational cost as random forests. We demonstrate the efficacy of iRF by finding known and promising interactions among biomolecules, of up to fifth and sixth order, in two data examples in transcriptional regulation and alternative splicing. Genomics has revolutionized biology, enabling the interrogation of whole transcriptomes, genome-wide binding sites for proteins, and many other molecular processes. However, individual genomic assays measure elements that interact in vivo as components of larger molecular machines. Understanding how these high-order interactions drive gene expression presents a substantial statistical challenge. Building on random forests (RFs) and random intersection trees (RITs) and through extensive, biologically inspired simulations, we developed the iterative random forest algorithm (iRF). iRF trains a feature-weighted ensemble of decision trees to detect stable, high-order interactions with the same order of computational cost as the RF. We demonstrate the utility of iRF for high-order interaction discovery in two prediction problems: enhancer activity in the early Drosophila embryo and alternative splicing of primary transcripts in human-derived cell lines. In Drosophila, among the 20 pairwise transcription factor interactions iRF identifies as stable (returned in more than half of bootstrap replicates), 80% have been previously reported as physical interactions. Moreover, third-order interactions, e.g., between Zelda (Zld), Giant (Gt), and Twist (Twi), suggest high-order relationships that are candidates for follow-up experiments. In human-derived cells, iRF rediscovered a central role of H3K36me3 in chromatin-mediated splicing regulation and identified interesting fifth- and sixth-order interactions, indicative of multivalent nucleosomes with specific roles in splicing regulation. By decoupling the order of interactions from the computational cost of identification, iRF opens additional avenues of inquiry into the molecular mechanisms underlying genome biology.
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13
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Chen T, van Steensel B. Comprehensive analysis of nucleocytoplasmic dynamics of mRNA in Drosophila cells. PLoS Genet 2017; 13:e1006929. [PMID: 28771467 PMCID: PMC5557608 DOI: 10.1371/journal.pgen.1006929] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 08/15/2017] [Accepted: 07/17/2017] [Indexed: 01/14/2023] Open
Abstract
Eukaryotic mRNAs undergo a cycle of transcription, nuclear export, and degradation. A major challenge is to obtain a global, quantitative view of these processes. Here we measured the genome-wide nucleocytoplasmic dynamics of mRNA in Drosophila cells by metabolic labeling in combination with cellular fractionation. By mathematical modeling of these data we determined rates of transcription, export and cytoplasmic decay for 5420 genes. We characterized these kinetic rates and investigated links with mRNA features, RNA-binding proteins (RBPs) and chromatin states. We found prominent correlations between mRNA decay rate and transcript size, while nuclear export rates are linked to the size of the 3'UTR. Transcription, export and decay rates are each associated with distinct spectra of RBPs. Specific classes of genes, such as those encoding cytoplasmic ribosomal proteins, exhibit characteristic combinations of rate constants, suggesting modular control. Binding of splicing factors is associated with faster rates of export, and our data suggest coordinated regulation of nuclear export of specific functional classes of genes. Finally, correlations between rate constants suggest global coordination between the three processes. Our approach provides insights into the genome-wide nucleocytoplasmic kinetics of mRNA and should be generally applicable to other cell systems. All mRNAs start from production in the nucleus, undergo exportation through nuclear pores and finally are degraded in the cytoplasm. A comprehensive characterization of the kinetic rates of all mRNAs is an important prerequisite for a global understanding of the regulation of the transcriptome and the cell. By conducting a time-series experiment and building a mathematical model, we trace the dynamics of mRNAs from the nucleus to the cytoplasm and determine the rates at each kinetic step at transcriptome-wide level. This information allows us to associate mRNA kinetic rates with a wealth of biological features and made some intriguing discoveries. We show mRNA decay is positively linked to transcript length while mRNA export is negatively linked to the length of the 3' UTR. We show binding of splicing factors is associated with faster rates of mRNA export. We provide evidence for global coordination between nuclear export an decay of mRNA. We show genes sharing specific functions tend to have similar nucleoplasmic kinetics, in which ribosomal proteins possessing special kinetic features exclusively stand out. Altogether, our integrated approach to quantitatively determine the rates of kinetic steps on a gene-by-gene basis provides a blueprint to obtain the global understanding of RNA regulation.
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Affiliation(s)
- Tao Chen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Bas van Steensel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands
- * E-mail:
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Plass M, Rasmussen SH, Krogh A. Highly accessible AU-rich regions in 3' untranslated regions are hotspots for binding of regulatory factors. PLoS Comput Biol 2017; 13:e1005460. [PMID: 28410363 PMCID: PMC5409497 DOI: 10.1371/journal.pcbi.1005460] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 04/28/2017] [Accepted: 03/14/2017] [Indexed: 12/24/2022] Open
Abstract
Post-transcriptional regulation is regarded as one of the major processes involved in the regulation of gene expression. It is mainly performed by RNA binding proteins and microRNAs, which target RNAs and typically affect their stability. Recent efforts from the scientific community have aimed at understanding post-transcriptional regulation at a global scale by using high-throughput sequencing techniques such as cross-linking and immunoprecipitation (CLIP), which facilitates identification of binding sites of these regulatory factors. However, the diversity in the experimental procedures and bioinformatics analyses has hindered the integration of multiple datasets and thus limited the development of an integrated view of post-transcriptional regulation. In this work, we have performed a comprehensive analysis of 107 CLIP datasets from 49 different RBPs in HEK293 cells to shed light on the complex interactions that govern post-transcriptional regulation. By developing a more stringent CLIP analysis pipeline we have discovered the existence of conserved regulatory AU-rich regions in the 3’UTRs where miRNAs and RBPs that regulate several processes such as polyadenylation or mRNA stability bind. Analogous to promoters, many factors have binding sites overlapping or in close proximity in these hotspots and hence the regulation of the mRNA may depend on their relative concentrations. This hypothesis is supported by RBP knockdown experiments that alter the relative concentration of RBPs in the cell. Upon AGO2 knockdown (KD), transcripts containing “free” target sites show increased expression levels compared to those containing target sites in hotspots, which suggests that target sites within hotspots are less available for miRNAs to bind. Interestingly, these hotspots appear enriched in genes with regulatory functions such as DNA binding and RNA binding. Taken together, our results suggest that hotspots are functional regulatory elements that define an extra layer of regulation of post-transcriptional regulatory networks. All the cells in a given organism contain the same genome, yet their phenotype can be very diverse. The vast majority of this diversity arises from the differences in the expression of genes and proteins in them. One of the main mechanisms involved in controlling the protein and mRNA repertoire in cells is post-transcriptional regulation. The recent development of high-throughput sequencing techniques gives us now an unprecedented opportunity to investigate how post-transcriptional regulation works and which are the elements involved in defining the final set of mRNAs and proteins inside cells. In this work, we have performed a comprehensive computational analysis of several post-transcriptional regulators in a commonly used human cell line in order to understand which factors are involved in post-transcriptional regulation and how they coordinate their function. The results of our analysis show that this process is orchestrated around small regions in the mRNAs where many regulators bind and may compete with each other to regulate the mRNAs. The investigation and characterization of these regions gives us insight into the underlying combinatorial control that causes gene expression to differ across cell types and in diseases.
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Affiliation(s)
- Mireya Plass
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen, Denmark
- * E-mail: (MP); (AK)
| | - Simon H. Rasmussen
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen, Denmark
| | - Anders Krogh
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen, Denmark
- * E-mail: (MP); (AK)
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Bombyx mori P-element Somatic Inhibitor (BmPSI) Is a Key Auxiliary Factor for Silkworm Male Sex Determination. PLoS Genet 2017; 13:e1006576. [PMID: 28103247 PMCID: PMC5289617 DOI: 10.1371/journal.pgen.1006576] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 02/02/2017] [Accepted: 01/10/2017] [Indexed: 12/23/2022] Open
Abstract
Manipulation of sex determination pathways in insects provides the basis for a wide spectrum of strategies to benefit agriculture and public health. Furthermore, insects display a remarkable diversity in the genetic pathways that lead to sex differentiation. The silkworm, Bombyx mori, has been cultivated by humans as a beneficial insect for over two millennia, and more recently as a model system for studying lepidopteran genetics and development. Previous studies have identified the B. mori Fem piRNA as the primary female determining factor and BmMasc as its downstream target, while the genetic scenario for male sex determination was still unclear. In the current study, we exploite the transgenic CRISPR/Cas9 system to generate a comprehensive set of knockout mutations in genes BmSxl, Bmtra2, BmImp, BmImpM, BmPSI and BmMasc, to investigate their roles in silkworm sex determination. Absence of Bmtra2 results in the complete depletion of Bmdsx transcripts, which is the conserved downstream factor in the sex determination pathway, and induces embryonic lethality. Loss of BmImp or BmImpM function does not affect the sexual differentiation. Mutations in BmPSI and BmMasc genes affect the splicing of Bmdsx and the female reproductive apparatus appeared in the male external genital. Intriguingly, we identify that BmPSI regulates expression of BmMasc, BmImpM and Bmdsx, supporting the conclusion that it acts as a key auxiliary factor in silkworm male sex determination. The sex determination system extremely diverse among organisms including insects in which even each order occupy a different manner of sex determination. The silkworm, Bombyx mori, is a lepidopteran model insect with economic importance. The mechanism of the silkworm sex determination has been in mystery for a long time until a Fem piRNA was identified as the primary female sex determinator recently. However, genetic and phenotypic proofs are urgently needed to fully exploit the mechanism, especially of the male sex determination. In the current study, we provided comprehensively genetic evidences by generating CRISPR/Cas9-mediated knockout mutations for those genes BmSxl, Bmtra2, BmImp, BmImpM, BmPSI and BmMasc, which were considered to be involved in insect sex determination. The results showed that mutations of BmSxl, BmImp and BmImpM had no physiological and morphological effects on the sexual development while Bmtra2 depletion caused Bmdsx splicing disappeared and induced embryonic lethality. Importantly, the BmPSI regulates expression of BmMasc, BmImpM and Bmdsx, supporting the conclusion that it acts as a key auxiliary factor to regulate the male sex determination in the silkworm.
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16
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Identification of Genes Mediating Drosophila Follicle Cell Progenitor Differentiation by Screening for Modifiers of GAL4::UAS Variegation. G3-GENES GENOMES GENETICS 2017; 7:309-318. [PMID: 27866148 PMCID: PMC5217119 DOI: 10.1534/g3.116.036038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Drosophila melanogaster ovarian follicle cell lineage provides a powerful system for investigating how epigenetic changes contribute to differentiation. Downstream from an epithelial stem cell, follicle progenitors undergo nine mitotic cell cycles before transitioning to the endocycle and initiating differentiation. During their proliferative phase, follicle progenitors experience Lsd1-dependent changes in epigenetic stability that can be monitored using GAL4::UAS variegation. Eventually, follicle progenitors acquire competence to respond to Delta, a Notch ligand present in the environment, which signals them to cease division and initiate differentiation. The time required to acquire competence determines the duration of mitotic cycling and hence the final number of follicle cells. We carried out a screen for dominant modifiers of variegation spanning nearly 70% of Drosophila euchromatin to identify new genes influencing follicle progenitor epigenetic maturation. The eight genes found include chromatin modifiers, but also cell cycle regulators and transcription factors. Five of the modifier genes accelerate the acquisition of progenitor competence and reduce follicle cell number, however, the other three genes affect follicle cell number in an unexpected manner.
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17
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Na H, Laver JD, Jeon J, Singh F, Ancevicius K, Fan Y, Cao WX, Nie K, Yang Z, Luo H, Wang M, Rissland O, Westwood JT, Kim PM, Smibert CA, Lipshitz HD, Sidhu SS. A high-throughput pipeline for the production of synthetic antibodies for analysis of ribonucleoprotein complexes. RNA (NEW YORK, N.Y.) 2016; 22:636-655. [PMID: 26847261 PMCID: PMC4793217 DOI: 10.1261/rna.055186.115] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 12/12/2015] [Indexed: 06/05/2023]
Abstract
Post-transcriptional regulation of mRNAs plays an essential role in the control of gene expression. mRNAs are regulated in ribonucleoprotein (RNP) complexes by RNA-binding proteins (RBPs) along with associated protein and noncoding RNA (ncRNA) cofactors. A global understanding of post-transcriptional control in any cell type requires identification of the components of all of its RNP complexes. We have previously shown that these complexes can be purified by immunoprecipitation using anti-RBP synthetic antibodies produced by phage display. To develop the large number of synthetic antibodies required for a global analysis of RNP complex composition, we have established a pipeline that combines (i) a computationally aided strategy for design of antigens located outside of annotated domains, (ii) high-throughput antigen expression and purification in Escherichia coli, and (iii) high-throughput antibody selection and screening. Using this pipeline, we have produced 279 antibodies against 61 different protein components of Drosophila melanogaster RNPs. Together with those produced in our low-throughput efforts, we have a panel of 311 antibodies for 67 RNP complex proteins. Tests of a subset of our antibodies demonstrated that 89% immunoprecipitate their endogenous target from embryo lysate. This panel of antibodies will serve as a resource for global studies of RNP complexes in Drosophila. Furthermore, our high-throughput pipeline permits efficient production of synthetic antibodies against any large set of proteins.
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Affiliation(s)
- Hong Na
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - John D Laver
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Jouhyun Jeon
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Fateh Singh
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Kristin Ancevicius
- Department of Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada L5L 1C6 Department of Cell and Systems Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada L5L 1C6
| | - Yujie Fan
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Wen Xi Cao
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Kun Nie
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1 Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Zhenglin Yang
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Hua Luo
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Miranda Wang
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8 Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
| | - Olivia Rissland
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8 Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
| | - J Timothy Westwood
- Department of Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada L5L 1C6 Department of Cell and Systems Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada L5L 1C6
| | - Philip M Kim
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1 Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8 Department of Computer Science, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Craig A Smibert
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8 Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Sachdev S Sidhu
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1 Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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Brooks AN, Duff MO, May G, Yang L, Bolisetty M, Landolin J, Wan K, Sandler J, Booth BW, Celniker SE, Graveley BR, Brenner SE. Regulation of alternative splicing in Drosophila by 56 RNA binding proteins. Genome Res 2015; 25:1771-80. [PMID: 26294686 PMCID: PMC4617972 DOI: 10.1101/gr.192518.115] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 08/19/2015] [Indexed: 12/26/2022]
Abstract
Alternative splicing is regulated by RNA binding proteins (RBPs) that recognize pre-mRNA sequence elements and activate or repress adjacent exons. Here, we used RNA interference and RNA-seq to identify splicing events regulated by 56 Drosophila proteins, some previously unknown to regulate splicing. Nearly all proteins affected alternative first exons, suggesting that RBPs play important roles in first exon choice. Half of the splicing events were regulated by multiple proteins, demonstrating extensive combinatorial regulation. We observed that SR and hnRNP proteins tend to act coordinately with each other, not antagonistically. We also identified a cross-regulatory network where splicing regulators affected the splicing of pre-mRNAs encoding other splicing regulators. This large-scale study substantially enhances our understanding of recent models of splicing regulation and provides a resource of thousands of exons that are regulated by 56 diverse RBPs.
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Affiliation(s)
- Angela N Brooks
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA; Broad Institute, Cambridge, Massachusetts 02142, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
| | - Michael O Duff
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Gemma May
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Li Yang
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Mohan Bolisetty
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Jane Landolin
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ken Wan
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jeremy Sandler
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Benjamin W Booth
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Susan E Celniker
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Brenton R Graveley
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Steven E Brenner
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA; Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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