701
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Zhang D, Duan Y, Cun J, Yang Q. Identification of Prognostic Alternative Splicing Signature in Breast Carcinoma. Front Genet 2019; 10:278. [PMID: 30984247 PMCID: PMC6448481 DOI: 10.3389/fgene.2019.00278] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 03/12/2019] [Indexed: 12/29/2022] Open
Abstract
Background Increasing evidence indicated a close relationship between aberrant splicing variants and carcinoma, whereas comprehensive analysis of prognostic alternative splicing (AS) profiling in breast cancer (BRCA) is lacking and largely unknown. Methods RNA-seq data and corresponding clinical information of BRCA patients were obtained and integrated from The Cancer Genome Atlas (TCGA). Then SpliceSeq software was used to assess seven AS types and calculate the Percent Spliced In (PSI) value. Univariate followed by stepwise multivariate Cox regression analyses identified survival associated AS events and constructed the AS signature, which were further sent for enrichment analysis, respectively. Besides, the splicing correlation network was constructed. Additionally, nomogram incorporating AS signature and clinicopathological characteristics was developed and its efficacy was evaluated with respect to discrimination, calibration and clinical utility. Results A total of 45,421 AS events were detected, among which 3071 events were found associated with overall survival (OS) after strict filtering. Parent genes of these prognostic events were involved in BRCA-related processes including NF-kappaB and HIF-1 signaling pathway. Besides, the final prognostic signature built with 20 AS events performed well with an area under the curve (AUC) of receiver operating characteristic (ROC) curve up to 0.957 for 5 years. And gene set enrichment analysis (GSEA) also confirmed the candidate 20 AS events contributed to progression of BRCA. Moreover, the nomogram that incorporated 20-AS-event-based classifier, age, pathological stage and Her-2 status showed good calibration and moderate discrimination, with C-index of 0.883 (95% CI, 0.844–0.921). Decision curve analysis (DCA) confirmed more benefit was added to survival prediction with our nomogram, especially in 5 or 8 years with threshold probability up to 80%. Finally, splicing correlation network revealed an obvious regulatory pattern of prognostic splicing factors (SF) in BRCA. Conclusion This study provided a systematic portrait of survival-associated AS events involved in BRCA and further presented a AS-clinicopathological nomogram, which could be conveniently used to assist the individualized prediction of long-term survival probability for BRCA patients. And a series of bioinformatic analysis provided a promising perspective for further uncovering the underlying mechanisms of AS events and validating therapeutic targets for BRCA.
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Affiliation(s)
- Dong Zhang
- Department of Breast Surgery, Qilu Hospital, Shandong University, Jinan, China
| | - Yi Duan
- Department of Breast Surgery, Qilu Hospital, Shandong University, Jinan, China
| | - Jinjing Cun
- Department of Breast Surgery, Qilu Hospital, Shandong University, Jinan, China
| | - Qifeng Yang
- Department of Breast Surgery, Qilu Hospital, Shandong University, Jinan, China.,Department of Pathology Tissue Bank, Qilu Hospital, Shandong University, Jinan, China
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702
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Stévant I, Nef S. Genetic Control of Gonadal Sex Determination and Development. Trends Genet 2019; 35:346-358. [PMID: 30902461 DOI: 10.1016/j.tig.2019.02.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 02/15/2019] [Accepted: 02/23/2019] [Indexed: 10/27/2022]
Abstract
Sex determination is the process by which the bipotential gonads develop as either testes or ovaries. With two distinct potential outcomes, the gonadal primordium offers a unique model for the study of cell fate specification and how distinct cell populations diverge from multipotent progenitors. This review focuses on recent advances in our understanding of the genetic programs and epigenetic mechanisms that regulate gonadal sex determination and the regulation of cell fate commitment in the bipotential gonads. We rely primarily on mouse data to illuminate the complex and dynamic genetic programs controlling cell fate decision and sex-specific cell differentiation during gonadal formation and gonadal sex determination.
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Affiliation(s)
- Isabelle Stévant
- Department of Genetic Medicine and Development, University of Geneva, 1211 Geneva, Switzerland; iGE3, Institute of Genetics and Genomics of Geneva, University of Geneva, 1211 Geneva, Switzerland; SIB, Swiss Institute of Bioinformatics, University of Geneva, 1211 Geneva, Switzerland
| | - Serge Nef
- Department of Genetic Medicine and Development, University of Geneva, 1211 Geneva, Switzerland; iGE3, Institute of Genetics and Genomics of Geneva, University of Geneva, 1211 Geneva, Switzerland.
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703
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Wang F, Cheng Y, Zhang C, Chang G, Geng X. A novel antisense oligonucleotide anchored on the intronic splicing enhancer of hTERT pre-mRNA inhibits telomerase activity and induces apoptosis in glioma cells. J Neurooncol 2019; 143:57-68. [PMID: 30887243 DOI: 10.1007/s11060-019-03150-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Accepted: 03/11/2019] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Alternative splicing of hTERT pre-mRNA is an important step in the regulation of telomerase activity, but the regulation mechanisms and functions remain unclear. METHODS RT-PCR analysis was used to detect hTERT splicing in glioma cell lines and brain tissues. TRAP assay was used to detect the telomerase activity. Then, we designed and synthesized 2'-O-methyl-RNA phosphorothioate AONs and transfected them into glioma cells to detect the changes in telomerase activity. MTT assay, plate colony formation assay, western blotting and Annexin V/PI assay were used to detect cell proliferation and apoptosis. At last, bioinformatics analyses were used to predict the expression and function of splicing protein SRSF2 in gliomas. RESULTS hTERT splicing occurs both in glioma cell lines and glioma patients' tissues. The telomerase activity was related to the expression level of the full-length hTERT, rather than the total hTERT transcript level. AON-Ex726 was complementary to the sequence of the intronic splicing enhancer (ISE) in intron six, and significantly altered the splicing pattern of hTERT pre-mRNA, reducing the expression level of the full-length hTERT mRNA and increasing the expression level of the -β hTERT mRNA. After transfection with AON-Ex726, the level of apoptosis was increased, while telomerase activity and cell proliferation were significantly decreased. By bioinformatic predictions, we found the AON-Ex726 anchoring sequence in ISE overlaps the binding site of SRSF2 protein, which is up-regulated during the development of gliomas. CONCLUSIONS Our findings provided new targets and important clues for the gene therapy of gliomas by regulating the alternative splicing pattern of hTERT pre-mRNA.
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Affiliation(s)
- Fei Wang
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, 300052, China
| | - Yajing Cheng
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, 300052, China
| | - Chi Zhang
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, 300052, China
| | - Guangming Chang
- Department of Clinical Laboratory, General Hospital, Tianjin Medical University, Tianjin, 300052, China
| | - Xin Geng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, 22nd Qixiangtai Road, Tianjin, 300070, China.
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704
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Planells B, Gómez-Redondo I, Pericuesta E, Lonergan P, Gutiérrez-Adán A. Differential isoform expression and alternative splicing in sex determination in mice. BMC Genomics 2019; 20:202. [PMID: 30871468 PMCID: PMC6419433 DOI: 10.1186/s12864-019-5572-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 02/27/2019] [Indexed: 02/06/2023] Open
Abstract
Background Alternative splicing (AS) may play an important role in gonadal sex determination (GSD) in mammals. The present study was designed to identify differentially expressed isoforms and AS modifications accompanying GSD in mice. Results Using deep RNA-sequencing, we performed a transcriptional analysis of XX and XY gonads during sex determination on embryonic days 11 (E11) and 12 (E12). Analysis of differentially expressed genes (DEG) identified hundreds of genes related to GSD and early sex differentiation that may represent good candidates for sex reversal. Expression at time point E11 in males was significantly enriched in RNA splicing and mRNA processing Gene Ontology terms. Differentially expressed isoform analysis identified hundreds of specific isoforms related to GSD, many of which showed no differences in the DEG analysis. Hundreds of AS events were identified as modified at E11 and E12. Female E11 gonads featured sex-biased upregulation of intron retention (in genes related to regulation of transcription, protein phosphorylation, protein transport and mRNA splicing) and exon skipping (in genes related to chromatin repression) suggesting AS as a post-transcription mechanism that controls sex determination of the bipotential fetal gonad. Conclusion Our data suggests an important role of splicing regulatory mechanisms for sex determination in mice. Electronic supplementary material The online version of this article (10.1186/s12864-019-5572-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Benjamín Planells
- Departamento de Reproducción Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain.,School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Isabel Gómez-Redondo
- Departamento de Reproducción Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain
| | - Eva Pericuesta
- Departamento de Reproducción Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain
| | - Patrick Lonergan
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Alfonso Gutiérrez-Adán
- Departamento de Reproducción Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain.
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705
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Angiolini F, Belloni E, Giordano M, Campioni M, Forneris F, Paronetto MP, Lupia M, Brandas C, Pradella D, Di Matteo A, Giampietro C, Jodice G, Luise C, Bertalot G, Freddi S, Malinverno M, Irimia M, Moulton JD, Summerton J, Chiapparino A, Ghilardi C, Giavazzi R, Nyqvist D, Gabellini D, Dejana E, Cavallaro U, Ghigna C. A novel L1CAM isoform with angiogenic activity generated by NOVA2-mediated alternative splicing. eLife 2019; 8:44305. [PMID: 30829570 PMCID: PMC6398979 DOI: 10.7554/elife.44305] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 02/08/2019] [Indexed: 12/13/2022] Open
Abstract
The biological players involved in angiogenesis are only partially defined. Here, we report that endothelial cells (ECs) express a novel isoform of the cell-surface adhesion molecule L1CAM, termed L1-ΔTM. The splicing factor NOVA2, which binds directly to L1CAM pre-mRNA, is necessary and sufficient for the skipping of L1CAM transmembrane domain in ECs, leading to the release of soluble L1-ΔTM. The latter exerts high angiogenic function through both autocrine and paracrine activities. Mechanistically, L1-ΔTM-induced angiogenesis requires fibroblast growth factor receptor-1 signaling, implying a crosstalk between the two molecules. NOVA2 and L1-ΔTM are overexpressed in the vasculature of ovarian cancer, where L1-ΔTM levels correlate with tumor vascularization, supporting the involvement of NOVA2-mediated L1-ΔTM production in tumor angiogenesis. Finally, high NOVA2 expression is associated with poor outcome in ovarian cancer patients. Our results point to L1-ΔTM as a novel, EC-derived angiogenic factor which may represent a target for innovative antiangiogenic therapies. Growing tumors stimulate the formation of new blood vessels to supply the oxygen and nutrients the cancerous cells need to stay alive. Stopping tumors from forming the blood vessels could therefore help us to treat cancer. To do so, we need to understand how different proteins control when and how blood vessels develop. Cells make proteins by first ‘transcribing’ genes to form RNA molecules. In many cases, the RNA then goes through a process called alternative splicing. Proteins known as splicing factors cut out different segments of the RNA molecule and stick together the remaining segments to form templates for protein production. This enables a single gene to produce many different variants of a protein. Angiolini, Belloni, Giordano et al. have now studied mouse and human versions of the cells that line the blood vessels grown by tumors. This revealed that a splicing factor called NOVA2 targets a protein called L1CAM, which is normally responsible for gluing adjacent cells together. Angiolini et al. found that NOVA2 splices L1CAM into a form not seen before. Instead of remaining anchored to cell surfaces, the newly identified form of L1CAM is released into the blood circulation, where it stimulates new blood vessels to grow. Samples taken from the blood vessels of human ovarian tumors showed high levels of both NOVA2 and the modified form of L1CAM, while blood vessels in healthy tissue contain no, or very low levels of both proteins. Therefore, if the new form of L1CAM can be detected in the blood, it could be used to help cancer diagnosis, and to indicate which patients would benefit from treatments that restrict the growth of blood vessels in tumors. Further work is now needed to explore these possibilities.
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Affiliation(s)
- Francesca Angiolini
- Unit of Gynecological Oncology Research, Program of Gynecological Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Elisa Belloni
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy
| | - Marco Giordano
- Unit of Gynecological Oncology Research, Program of Gynecological Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Matteo Campioni
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Federico Forneris
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Maria Paola Paronetto
- Department of Movement, Human and Health Sciences, Università degli Studi di Roma "Foro Italico", Rome, Italy
| | - Michela Lupia
- Unit of Gynecological Oncology Research, Program of Gynecological Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Chiara Brandas
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy
| | - Davide Pradella
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy.,Università degli Studi di Pavia, Pavia, Italy
| | - Anna Di Matteo
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy
| | | | - Giovanna Jodice
- Molecular Medicine Program, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Chiara Luise
- Molecular Medicine Program, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Giovanni Bertalot
- Molecular Medicine Program, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Stefano Freddi
- Molecular Medicine Program, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | | | - Manuel Irimia
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | | | | | - Antonella Chiapparino
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Carmen Ghilardi
- Laboratory of Biology and Treatment of Metastasis, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Raffaella Giavazzi
- Laboratory of Biology and Treatment of Metastasis, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Daniel Nyqvist
- Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Davide Gabellini
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Elisabetta Dejana
- FIRC Institute of Molecular Oncology, Milan, Italy.,Rudbeck Laboratory and Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Ugo Cavallaro
- Unit of Gynecological Oncology Research, Program of Gynecological Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Claudia Ghigna
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy
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706
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Froussios K, Mourão K, Simpson G, Barton G, Schurch N. Relative Abundance of Transcripts ( RATs): Identifying differential isoform abundance from RNA-seq. F1000Res 2019; 8:213. [PMID: 30906538 PMCID: PMC6426083 DOI: 10.12688/f1000research.17916.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/08/2019] [Indexed: 12/16/2022] Open
Abstract
The biological importance of changes in RNA expression is reflected by the wide variety of tools available to characterise these changes from RNA-seq data. Several tools exist for detecting differential transcript isoform usage (DTU) from aligned or assembled RNA-seq data, but few exist for DTU detection from alignment-free RNA-seq quantifications. We present the RATs, an R package that identifies DTU transcriptome-wide directly from transcript abundance estimates. RATs is unique in applying bootstrapping to estimate the reliability of detected DTU events and shows good performance at all replication levels (median false positive fraction < 0.05). We compare RATs to two existing DTU tools, DRIM-Seq & SUPPA2, using two publicly available simulated RNA-seq datasets and a published human RNA-seq dataset, in which 248 genes have been previously identified as displaying significant DTU. RATs with default threshold values on the simulated Human data has a sensitivity of 0.55, a Matthews correlation coefficient of 0.71 and a false discovery rate (FDR) of 0.04, outperforming both other tools. Applying the same thresholds for SUPPA2 results in a higher sensitivity (0.61) but poorer FDR performance (0.33). RATs and DRIM-seq use different methods for measuring DTU effect-sizes complicating the comparison of results between these tools, however, for a likelihood-ratio threshold of 30, DRIM-Seq has similar FDR performance to RATs (0.06), but worse sensitivity (0.47). These differences persist for the simulated drosophila dataset. On the published human RNA-seq dataset the greatest agreement between the tools tested is 53%, observed between RATs and SUPPA2. The bootstrapping quality filter in RATs is responsible for removing the majority of DTU events called by SUPPA2 that are not reported by RATs. All methods, including the previously published qRT-PCR of three of the 248 detected DTU events, were found to be sensitive to annotation differences between Ensembl v60 and v87.
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Affiliation(s)
- Kimon Froussios
- Division of Computational Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Kira Mourão
- Division of Computational Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Gordon Simpson
- Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.,Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.,The James Hutton Institute, Invergowrie, Dundee, DD2 4DA, UK
| | - Geoff Barton
- Division of Computational Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Nicholas Schurch
- Division of Computational Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
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707
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Abstract
Single-cell RNA-seq (scRNA-seq) provides a comprehensive measurement of stochasticity in transcription, but the limitations of the technology have prevented its application to dissect variability in RNA processing events such as splicing. In this chapter, we review the challenges in splicing isoform quantification in scRNA-seq data and discuss BRIE (Bayesian regression for isoform estimation), a recently proposed Bayesian hierarchical model which resolves these problems by learning an informative prior distribution from sequence features. We illustrate the usage of BRIE with a case study on 130 mouse cells during gastrulation.
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708
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Robinson TJ, Freedman JA, Al Abo M, Deveaux AE, LaCroix B, Patierno BM, George DJ, Patierno SR. Alternative RNA Splicing as a Potential Major Source of Untapped Molecular Targets in Precision Oncology and Cancer Disparities. Clin Cancer Res 2019; 25:2963-2968. [PMID: 30755441 PMCID: PMC6653604 DOI: 10.1158/1078-0432.ccr-18-2445] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 09/18/2018] [Accepted: 01/29/2019] [Indexed: 12/12/2022]
Abstract
Studies of alternative RNA splicing (ARS) have the potential to provide an abundance of novel targets for development of new biomarkers and therapeutics in oncology, which will be necessary to improve outcomes for patients with cancer and mitigate cancer disparities. ARS, a key step in gene expression enabling individual genes to encode multiple proteins, is emerging as a major driver of abnormal phenotypic heterogeneity. Recent studies have begun to identify RNA splicing-related genetic and genomic variation in tumors, oncogenes dysregulated by ARS, RNA splice variants driving race-related cancer aggressiveness and drug response, spliceosome-dependent transformation, and RNA splicing-related immunogenic epitopes in cancer. In addition, recent studies have begun to identify and test, preclinically and clinically, approaches to modulate and exploit ARS for therapeutic application, including splice-switching oligonucleotides, small molecules targeting RNA splicing or RNA splice variants, and combination regimens with immunotherapies. Although ARS data hold such promise for precision oncology, inclusion of studies of ARS in translational and clinical cancer research remains limited. Technologic developments in sequencing and bioinformatics are being routinely incorporated into clinical oncology that permit investigation of clinically relevant ARS events, yet ARS remains largely overlooked either because of a lack of awareness within the clinical oncology community or perceived barriers to the technical complexity of analyzing ARS. This perspective aims to increase such awareness, propose immediate opportunities to improve identification and analysis of ARS, and call for bioinformaticians and cancer researchers to work together to address the urgent need to incorporate ARS into cancer biology and precision oncology.
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Affiliation(s)
| | - Jennifer A Freedman
- Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, North Carolina
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina
| | - Muthana Al Abo
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina
| | - April E Deveaux
- Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, North Carolina
| | - Bonnie LaCroix
- Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, North Carolina
| | - Brendon M Patierno
- Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, North Carolina
| | - Daniel J George
- Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, North Carolina
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina
| | - Steven R Patierno
- Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, North Carolina.
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina
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709
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Mettl3 Regulates Osteogenic Differentiation and Alternative Splicing of Vegfa in Bone Marrow Mesenchymal Stem Cells. Int J Mol Sci 2019; 20:ijms20030551. [PMID: 30696066 PMCID: PMC6387109 DOI: 10.3390/ijms20030551] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 01/20/2019] [Accepted: 01/25/2019] [Indexed: 12/16/2022] Open
Abstract
Bone mesenchymal stem cells (BMSCs) can be a useful cell resource for developing biological treatment strategies for bone repair and regeneration, and their therapeutic applications hinge on an understanding of their physiological characteristics. N6-methyl-adenosine (m6A) is the most prevalent internal chemical modification of mRNAs and has recently been reported to play important roles in cell lineage differentiation and development. However, little is known about the role of m6A modification in the cell differentiation of BMSCs. To address this issue, we investigated the expression of N6-adenosine methyltransferases (Mettl3 and Mettl14) and demethylases (Fto and Alkbh5) and found that Mettl3 was upregulated in BMSCs undergoing osteogenic induction. Furthermore, we knocked down Mettl3 and demonstrated that Mettl3 knockdown decreased the expression of bone formation-related genes, such as Runx2 and Osterix. The alkaline phosphatase (ALP) activity and the formation of mineralized nodules also decreased after Mettl3 knockdown. RNA sequencing analysis revealed that a vast number of genes affected by Mettl3 knockdown were associated with osteogenic differentiation and bone mineralization. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis revealed that the phosphatidylinositol 3-kinase/AKT (PI3K-Akt) signaling pathway appeared to be one of the most enriched pathways, and Western blotting results showed that Akt phosphorylation was significantly reduced after Mettl3 knockdown. Mettl3 has been reported to play an important role in regulating alternative splicing of mRNA in previous research. In this study, we found that Mettl3 knockdown not only reduced the expression of Vegfa but also decreased the level of its splice variants, vegfa-164 and vegfa-188, in Mettl3-deficient BMSCs. These findings might contribute to novel progress in understanding the role of epitranscriptomic regulation in the osteogenic differentiation of BMSCs and provide a promising perspective for new therapeutic strategies for bone regeneration.
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710
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Olender J, Lee NH. Role of Alternative Splicing in Prostate Cancer Aggressiveness and Drug Resistance in African Americans. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1164:119-139. [PMID: 31576545 PMCID: PMC6777849 DOI: 10.1007/978-3-030-22254-3_10] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Alternative splicing, the process of removing introns and joining exons of pre-mRNA, is critical for growth, development, tissue homeostasis, and species diversity. Dysregulation of alternative splicing can initiate and drive disease. Aberrant alternative splicing has been shown to promote the "hallmarks of cancer" in both hematological and solid cancers. Of interest, recent work has focused on the role of alternative splicing in prostate cancer and prostate cancer health disparities. We will provide a review of prostate cancer health disparities involving the African American population, alternative RNA splicing, and alternative splicing in prostate cancer. Lastly, we will summarize our work on differential alternative splicing in prostate cancer disparities and its implications for disparate health outcomes and therapeutic targets.
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Affiliation(s)
- Jacqueline Olender
- Department of Pharmacology and Physiology, GW Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Norman H Lee
- Department of Pharmacology and Physiology, GW Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA.
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711
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Networks of mRNA Processing and Alternative Splicing Regulation in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1157:1-27. [PMID: 31342435 DOI: 10.1007/978-3-030-19966-1_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
mRNA processing events introduce an intricate layer of complexity into gene expression processes, supporting a tremendous level of diversification of the genome's coding and regulatory potential, particularly in vertebrate species. The recent development of massive parallel sequencing methods and their adaptation to the identification and quantification of different RNA species and the dynamics of mRNA metabolism and processing has generated an unprecedented view over the regulatory networks that are established at this level, which contribute to sustain developmental, tissue specific or disease specific gene expression programs. In this chapter, we provide an overview of the recent evolution of transcriptome profiling methods and the surprising insights that have emerged in recent years regarding distinct mRNA processing events - from the 5' end to the 3' end of the molecule.
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712
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Wan L, Yu W, Shen E, Sun W, Liu Y, Kong J, Wu Y, Han F, Zhang L, Yu T, Zhou Y, Xie S, Xu E, Zhang H, Lai M. SRSF6-regulated alternative splicing that promotes tumour progression offers a therapy target for colorectal cancer. Gut 2019; 68:118-129. [PMID: 29114070 DOI: 10.1136/gutjnl-2017-314983] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/25/2017] [Accepted: 10/21/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To investigate the molecular function of splicing factor SRSF6 in colorectal cancer (CRC) progression and discover candidate chemicals for cancer therapy through targeting SRSF6. DESIGN We performed comprehensive analysis for the expression of SRSF6 in 311 CRC samples, The Cancer Genome Atlas and Gene Expression Omnibus (GEO) database. Functional analysis of SRSF6 in CRC was performed in vitro and in vivo. SRSF6-regulated alternative splicing (AS) and its binding motif were identified by next-generation RNA-sequencing and RNA immunoprecipitation sequencing (RIP-seq), which was validated by gel shift and minigene reporter assay. ZO-1 exon23 AS was investigated to mediate the function of SRSF6 in vitro and in vivo. Based on the analysis of domain-specific role, SRSF6-targeted inhibitor was discovered de novoby virtual screening in 4855 FDA-approved drugs and its antitumour effects were evaluated in vitroand in vivo. RESULTS SRSF6 was frequently upregulated in CRC samples and associated with poor prognosis, which promoted proliferation and metastasis in vitro and in vivo. We identified SRSF6-regulated AS targets and discovered the SRSF6 binding motif. Particularly, SRSF6 regulates ZO-1 aberrant splicing to function as an oncogene by binding directly to its motif in the exon23. Based on the result that SRSF6 RRM2 domain plays key roles in regulating AS and biological function, indacaterol, a β2-adrenergic receptor agonist approved for chronic obstructive pulmonary disease treatment, is identified as the inhibitor of SRSF6 to suppress CRC tumourigenicity. CONCLUSIONS SRSF6 functions the important roles in mediating CRC progression through regulating AS, and indacaterol is repositioned as an antitumour drug through targeting SRSF6. ACCESSION NUMBERS The accession numbers for sequencing data are SRP111763 and SRP111797.
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Affiliation(s)
- Ledong Wan
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Wenying Yu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Enhui Shen
- College of Agriculture and Biotechnology, Institute of Bioinformatics, Zhejiang University, Hangzhou, China
| | - Wenjie Sun
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yuan Liu
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jianlu Kong
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yihua Wu
- Department of Toxicology, School of Public Health, Zhejiang University, Hangzhou, Zhejiang, China
| | - Fengyan Han
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Lei Zhang
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China.,Department of Pharmacology, China Pharmaceutical University, Nanjing, China
| | - Tianze Yu
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yuwei Zhou
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Sunzhe Xie
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Enping Xu
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Honghe Zhang
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China
| | - Maode Lai
- Department of Pathology, Key Laboratory of Disease Proteomics of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, China.,Department of Pharmacology, China Pharmaceutical University, Nanjing, China
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713
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Regulation of P2X7 receptor expression and function in the brain. Brain Res Bull 2018; 151:153-163. [PMID: 30593878 DOI: 10.1016/j.brainresbull.2018.12.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/19/2018] [Accepted: 12/12/2018] [Indexed: 02/07/2023]
Abstract
Because of its prominent role in driving inflammatory processes, the ATP-gated purinergic P2X7 receptor has attracted much attention over the past decade as a potential therapeutic target for numerous human conditions, particularly diseases of the central nervous system, including neurodegenerative diseases (e.g. Alzheimer's and Huntington's disease), psychiatric disorders (e.g. schizophrenia and depression) and the neurological disease, epilepsy. Evidence stems from studies using experimental models and patient tissue showing changes in P2X7 expression and function under pathological conditions and beneficial effects provided by P2X7 antagonism. Apart from promoting neuroinflammation, P2X7, however, also impacts on other pathological processes in the brain, including cell death, hyperexcitability, changes in neurotransmitter release and neurogenesis. Reports also suggest a role for P2X7 in the maintenance of blood-brain-barrier integrity. It therefore comes as no surprise that the regulation of P2X7 expression and function is complex, providing tight control on P2X7 activation. Much progress has been made in understanding how P2X7 is regulated during physiological and pathological conditions and what the consequences are of pathological P2X7 expression and function. Regulatory mechanisms altering P2X7 expression include transcriptional and post-translational regulation including nucleotide polymorphisms, promoter regulation via DNA methylation, transcription factors (e.g. Sp1 and HIF-1α), the generation of different splice variants and receptor phosphorylation, glycosylation and palmitoylation. Finally, more recently, reports have also shown P2X7-targeting by microRNAs, blocking P2X7 translation into functional proteins. The present review provides a broad overview of what is known to-date about the complex regulation of P2X7 expression with a particular emphasis on the brain and how each of these regulatory mechanisms impacts on receptor function and pathology.
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714
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Uddin MB, Roy KR, Hosain SB, Khiste SK, Hill RA, Jois SD, Zhao Y, Tackett AJ, Liu YY. An N 6-methyladenosine at the transited codon 273 of p53 pre-mRNA promotes the expression of R273H mutant protein and drug resistance of cancer cells. Biochem Pharmacol 2018; 160:134-145. [PMID: 30578766 DOI: 10.1016/j.bcp.2018.12.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 12/18/2018] [Indexed: 02/06/2023]
Abstract
Mutant p53 proteins that promote cancer cell invasive growth, metastasis and drug resistance emerge as therapeutic targets. Previously, we reported that suppression of ceramide glycosylation restored wild-type p53 protein and tumor suppressing function in cancer cells heterozygously carrying p53 R273H, a hot-spot missense mutation; however, the mechanisms underlying the control of mutant protein expression remain elusive. Herein, we report that an N6-methyladenosine (m6A) at the point-mutated codon 273 (G > A) of p53 pre-mRNA determines the mutant protein expression. Methylation of the transited adenosine was catalyzed by methyltransferase like 3 (METTL3), and this m6A-RNA promoted a preferential pre-mRNA splicing; consequently, the produced p53 R273H mutant protein resulted in acquired multidrug resistance in colon cancer cells. Furthermore, glycosphingolipids (particularly globotriaosylceramide) generated from serial ceramide glycosylation were seen to activate cSrc and β-catenin signaling so as to upregulate METTL3 expression, in turn promoting expression of p53 R273H mutant protein, with consequent drug resistance. Conversely, either silencing METTL3 expression by using small interfering RNA (siRNA) or inhibiting RNA methylation with neplanocin A suppressed m6A formation in p53 pre-mRNA, and substantially increased the level of phosphorylated p53 protein (Ser15) and its function in cells heterozygously carrying the R273H mutation, thereby re-sensitizing these cells to anticancer drugs. Concordantly, suppression of ceramide glycosylation repressed METTL3 expression and m6A formation in p53 pre-mRNA, thus sensitizing cells carrying R273H to anticancer drugs. This study uncovers a novel function of pre-mRNA m6A as a determinant of mutant protein expression in cancer cells heterozygously carrying the TP53 R273H mutation. Suppressing both RNA methylation and ceramide glycosylation might constitute an efficacious and specific approach for targeting TP53 missense mutations coding for a G > A transition, thereby improving cancer treatments.
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Affiliation(s)
- Mohammad B Uddin
- School of Basic Pharmaceutical and Toxicological Sciences, University of Louisiana at Monroe, Monroe, LA 71201, USA
| | - Kartik R Roy
- School of Basic Pharmaceutical and Toxicological Sciences, University of Louisiana at Monroe, Monroe, LA 71201, USA
| | - Salman B Hosain
- School of Basic Pharmaceutical and Toxicological Sciences, University of Louisiana at Monroe, Monroe, LA 71201, USA
| | - Sachin K Khiste
- School of Basic Pharmaceutical and Toxicological Sciences, University of Louisiana at Monroe, Monroe, LA 71201, USA
| | - Ronald A Hill
- School of Basic Pharmaceutical and Toxicological Sciences, University of Louisiana at Monroe, Monroe, LA 71201, USA
| | - Seetharama D Jois
- School of Basic Pharmaceutical and Toxicological Sciences, University of Louisiana at Monroe, Monroe, LA 71201, USA
| | - Yunfeng Zhao
- Department of Pharmacology, Toxicology & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Alan J Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Yong-Yu Liu
- School of Basic Pharmaceutical and Toxicological Sciences, University of Louisiana at Monroe, Monroe, LA 71201, USA.
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715
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Black AJ, Schilder RJ, Kimball SR. Palmitate- and C6 ceramide-induced Tnnt3 pre-mRNA alternative splicing occurs in a PP2A dependent manner. Nutr Metab (Lond) 2018; 15:87. [PMID: 30564278 PMCID: PMC6296074 DOI: 10.1186/s12986-018-0326-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/10/2018] [Indexed: 12/24/2022] Open
Abstract
Background In a previous study, we showed that consumption of diets enriched in saturated fatty acids causes changes in alternative splicing of pre-mRNAs encoding a number of proteins in rat skeletal muscle, including the one encoding skeletal muscle Troponin T (Tnnt3). However, whether saturated fatty acids act directly on muscle cells to modulate alternative pre-mRNA splicing was not assessed. Moreover, the signaling pathway through which saturated fatty acids act to promote changes in alternative splicing is unknown. Therefore, the objective of the present study was to characterize the signaling pathway through which saturated fatty acids act to modulate Tnnt3 alternative splicing. Methods The effects of treatment of L6 myotubes with saturated (palmitate), mono- (oleate), or polyunsaturated (linoleate) fatty acids on alternative splicing of pre-mRNA was assessed using Tnnt3 as a marker gene. Results Palmitate treatment caused a two-fold change (p < 0.05) in L6 myotube Tnnt3 alternative splicing whereas treatment with either oleate or linoleate had minimal effects compared to control myotubes. Treatment with a downstream metabolite of palmitate, ceramide, had effects similar to palmitate on Tnnt3 alternative splicing and inhibition of de novo ceramide biosynthesis blocked the palmitate-induced alternative splicing changes. The effects of palmitate and ceramide on Tnnt3 alternative splicing were accompanied by a 40–50% reduction in phosphorylation of Akt on S473. However, inhibition of de novo ceramide biosynthesis did not prevent palmitate-induced Akt dephosphorylation, suggesting that palmitate may act in an Akt-independent manner to modulate Tnnt3 alternative splicing. Instead, pre-treatment with okadaic acid at concentrations that selectively inhibit protein phosphatase 2A (PP2A) blocked both palmitate- and ceramide-induced changes in Tnnt3 alternative splicing, suggesting that palmitate and ceramide act through PP2A to modulate Tnnt3 alternative splicing. Conclusions Overall, the data show that fatty acid saturation level and ceramides are important factors modulating alternative pre-mRNA splicing through activation of PP2A. Electronic supplementary material The online version of this article (10.1186/s12986-018-0326-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam J Black
- 1Department of Cellular and Molecular Physiology, Penn State College of Medicine, H166, 500 University Drive, Hershey, PA 17033 USA.,Present Address: Department of Cell Biology and Physiology, 6330 Medical Biomolecular Research Building, 111 Mason Farm Rd, Chapel Hill, NC 27599 USA
| | - Rudolf J Schilder
- 3Department of Entomology and Biology, Penn State University, University Park, PA USA
| | - Scot R Kimball
- 1Department of Cellular and Molecular Physiology, Penn State College of Medicine, H166, 500 University Drive, Hershey, PA 17033 USA
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716
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Zhao L, Wang C, Lehman ML, He M, An J, Svingen T, Spiller CM, Ng ET, Nelson CC, Koopman P. Transcriptomic analysis of mRNA expression and alternative splicing during mouse sex determination. Mol Cell Endocrinol 2018; 478:84-96. [PMID: 30053582 DOI: 10.1016/j.mce.2018.07.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/23/2018] [Accepted: 07/23/2018] [Indexed: 12/15/2022]
Abstract
Mammalian sex determination hinges on sexually dimorphic transcriptional programs in developing fetal gonads. A comprehensive view of these programs is crucial for understanding the normal development of fetal testes and ovaries and the etiology of human disorders of sex development (DSDs), many of which remain unexplained. Using strand-specific RNA-sequencing, we characterized the mouse fetal gonadal transcriptome from 10.5 to 13.5 days post coitum, a key time window in sex determination and gonad development. Our dataset benefits from a greater sensitivity, accuracy and dynamic range compared to microarray studies, allows global dynamics and sex-specificity of gene expression to be assessed, and provides a window to non-transcriptional events such as alternative splicing. Spliceomic analysis uncovered female-specific regulation of Lef1 splicing, which may contribute to the enhanced WNT signaling activity in XX gonads. We provide a user-friendly visualization tool for the complete transcriptomic and spliceomic dataset as a resource for the field.
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Affiliation(s)
- Liang Zhao
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Chenwei Wang
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, Queensland, 4102, Australia
| | - Melanie L Lehman
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, Queensland, 4102, Australia
| | - Mingyu He
- Longsoft, Brisbane, Queensland, 4109, Australia
| | - Jiyuan An
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, Queensland, 4102, Australia
| | - Terje Svingen
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Cassy M Spiller
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Ee Ting Ng
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Colleen C Nelson
- Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Princess Alexandra Hospital, Translational Research Institute, Brisbane, Queensland, 4102, Australia
| | - Peter Koopman
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia.
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717
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Smith M, Flodman PL. Expanded Insights Into Mechanisms of Gene Expression and Disease Related Disruptions. Front Mol Biosci 2018; 5:101. [PMID: 30542652 PMCID: PMC6277798 DOI: 10.3389/fmolb.2018.00101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 11/02/2018] [Indexed: 12/31/2022] Open
Abstract
Definitive molecular diagnoses in disorders apparently due to genetic or genomic defects are still lacking in a significant number of investigated cases, despite use of studies designed to discover defects in the protein coding regions of the genome. Increasingly studies are being designed to search for defects in the non-protein coding genome, and for alterations in gene expression. Here we review new insights into genomic elements involved in control of gene expression, including methods to analyze chromatin that is accessible for transcription factor binding, enhancers, chromatin looping, transcription, RNA binding proteins, and alternative splicing. We review new studies on levels of genome organization, including the occurrence of transcriptional domains and their boundary elements. Information is presented on specific malformation syndromes that arise due to structural genomic changes that impact the non-protein coding genome and sometimes impact specific transcriptional domains. We also review convergence of genome-wide association with studies of gene expression, discoveries related to expression quantitative trait loci and splicing quantitative trait loci and the relevance of these to specific complex common diseases. Aspects of epigenetic mechanisms and clinical applications of analyses of methylation signatures are also discussed.
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Affiliation(s)
- Moyra Smith
- Department of Pediatrics, University of California, Irvine, Irvine, CA, United States
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718
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Ratcliffe CDH, Siddiqui N, Coelho PP, Laterreur N, Cookey TN, Sonenberg N, Park M. HGF-induced migration depends on the PI(3,4,5)P 3-binding microexon-spliced variant of the Arf6 exchange factor cytohesin-1. J Cell Biol 2018; 218:285-298. [PMID: 30404949 PMCID: PMC6314551 DOI: 10.1083/jcb.201804106] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 09/19/2018] [Accepted: 10/17/2018] [Indexed: 12/19/2022] Open
Abstract
Splice variants of the Arf6 guanine exchange factor cytohesin-1 display differential affinity for PI(4,5)P2 and PI(3,4,5)P3. Ratcliffe et al. show that the specific lipid binding of the diglycine variant of cytohesin-1 is needed for HGF-dependent cell migration and establishment of the leading edge, thereby regulating cancer cell migration following activation of the proto-oncogenic receptor tyrosine kinase Met. Differential inclusion or skipping of microexons is an increasingly recognized class of alternative splicing events. However, the functional significance of microexons and their contribution to signaling diversity is poorly understood. The Met receptor tyrosine kinase (RTK) modulates invasive growth and migration in development and cancer. Here, we show that microexon switching in the Arf6 guanine nucleotide exchange factor cytohesin-1 controls Met-dependent cell migration. Cytohesin-1 isoforms, differing by the inclusion of an evolutionarily conserved three-nucleotide microexon in the pleckstrin homology domain, display differential affinity for PI(4,5)P2 (triglycine) and PI(3,4,5)P3 (diglycine). We show that selective phosphoinositide recognition by cytohesin-1 isoforms promotes distinct subcellular localizations, whereby the triglycine isoform localizes to the plasma membrane and the diglycine to the leading edge. These data highlight microexon skipping as a mechanism to spatially restrict signaling and provide a mechanistic link between RTK-initiated phosphoinositide microdomains and Arf6 during signal transduction and cancer cell migration.
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Affiliation(s)
- Colin D H Ratcliffe
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Nadeem Siddiqui
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Paula P Coelho
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Nancy Laterreur
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
| | - Tumini N Cookey
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
| | - Nahum Sonenberg
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Morag Park
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada .,Department of Biochemistry, McGill University, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Oncology, McGill University, Montreal, Quebec, Canada
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719
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Mao M, Hu Y, Yang Y, Qian Y, Wei H, Fan W, Yang Y, Li X, Wang Z. Modeling and Predicting the Activities of Trans-Acting Splicing Factors with Machine Learning. Cell Syst 2018; 7:510-520.e4. [PMID: 30414922 DOI: 10.1016/j.cels.2018.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 05/10/2018] [Accepted: 09/19/2018] [Indexed: 02/06/2023]
Abstract
Alternative splicing (AS) is generally regulated by trans-splicing factors that specifically bind to cis-elements in pre-mRNAs. The human genome encodes ∼1,500 RNA binding proteins (RBPs) that potentially regulate AS, yet their functions remain largely unknown. To explore their potential activities, we fused the putative functional domains of RBPs to a sequence-specific RNA-binding domain and systemically analyzed how these engineered factors affect splicing. We discovered that ∼80% of low-complexity domains in endogenous RBPs displayed distinct context-dependent activities in regulating splicing, indicating that AS is under more extensive regulation than previously expected. We developed a machine learning approach to classify and predict the activities of RBPs based on their sequence compositions and further validated this model using endogenous RBPs and synthetic polypeptides. These results represent a systematic inspection, modeling, prediction, and validation of how RBP sequences affect their activities in controlling splicing, paving the way for de novo engineering of artificial splicing factors.
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Affiliation(s)
- Miaowei Mao
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China; Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Yue Hu
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yun Yang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yajie Qian
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Huanhuan Wei
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wei Fan
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Yi Yang
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Xiaoling Li
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Zefeng Wang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China.
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720
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Xing F, Zhang C, Kong Z. Cloning and expression of lin-28 homolog B gene in the onset of puberty in Duolang sheep. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2018; 32:23-30. [PMID: 30381750 PMCID: PMC6325404 DOI: 10.5713/ajas.18.0276] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 09/14/2018] [Indexed: 11/27/2022]
Abstract
Objective Recent studies have demonstrated that lin-28 homolog B (LIN28B)/miRNA let-7 (let-7) plays a role in the regulation of pubertal onset in mammals. However, the role of LIN28B/let-7 in the onset of ovine puberty remains unknown. We cloned the Duolang sheep Lin28B cDNA sequence, detected the expression change of LIN28B, let-7a and let-7g in hypothalamus, pituitary and ovary tissues at three different pubertal stages. Methods The reverse transcriptase polymerase chain reaction (RT-PCR) was used to clone the cDNA sequence of LIN28B gene from Duolang sheep and the bioinformatics methods were applied to analyze the amino acid sequence of LIN28B protein. The mRNA expression levels of the LIN28B gene at different pubertal stages were examined by real time RT-PCR. Results LIN28B cDNA of Duolang sheep was cloned, and two transcripts were obtained. The amino acid sequence of transcript 1 shares 99.60%, 98.78%, and 94.80% identity with those of goat, wild yak and pig, respectively. Strong LIN28B mRNA expression was detected in the hypothalamus, pituitary, ovary, oviduct and uterus, while moderate expression was found in the liver, kidney, spleen and heart, weak expression was observed in the heart. No expression was found in the lungs. Quantitative real-time PCR (QPCR) and western-blot analysis revealed that the LIN28B was highly expressed in the hypothalamus and ovary at prepuberty stages, and this expression significantly decreased from the prepuberty to puberty stages (p<0.05). Markedly increased levels of mRNA expression were detected in the pituitary from prepuberty to puberty (p<0.05) and then significantly decreased from puberty to postpuberty (p<0.05). The expression levels of let-7a and let-7g showed no significant changes among different pubertal stages (p>0.05). Conclusion These results provided a foundation for determining the functions of LIN28B/let-7 and their role in the onset of sheep puberty.
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Affiliation(s)
- Feng Xing
- College of Animal Science, Tarim University, Alar, XinJiang 843300, China.,Key laboratory of Tarim, Animal Husbandry Science and Technology, XinJiang Production & Construction Corps, Alar, Xinjiang 843300, China
| | - Chaoyang Zhang
- College of Animal Science, Tarim University, Alar, XinJiang 843300, China.,Key laboratory of Tarim, Animal Husbandry Science and Technology, XinJiang Production & Construction Corps, Alar, Xinjiang 843300, China
| | - Zhengquan Kong
- College of Animal Science, Tarim University, Alar, XinJiang 843300, China.,Key laboratory of Tarim, Animal Husbandry Science and Technology, XinJiang Production & Construction Corps, Alar, Xinjiang 843300, China
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721
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Pan H, Shi Y, Chen S, Yang Y, Yue Y, Zhan L, Dai L, Dong H, Hong W, Shi F, Jin Y. Competing RNA pairings in complex alternative splicing of a 3' variable region. RNA (NEW YORK, N.Y.) 2018; 24:1466-1480. [PMID: 30065023 PMCID: PMC6191721 DOI: 10.1261/rna.066225.118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/24/2018] [Indexed: 05/15/2023]
Abstract
Alternative pre-mRNA splicing remarkably expands protein diversity in eukaryotes. Drosophila PGRP-LC can generate three major 3' splice isoforms that exhibit distinct innate immune recognition and defenses against various microbial infections. However, the regulatory mechanisms underlying the uniquely biased splicing pattern at the 3' variable region remain unclear. Here we show that competing RNA pairings control the unique splicing of the 3' variable region of Drosophila PGRP-LC pre-mRNA. We reveal three roles by which these RNA pairings jointly regulate the 3' variant selection through activating the proximal 3' splice site and concurrently masking the intron-proximal 5' splice site, in combination with physical competition of RNA pairing. We also reveal that competing RNA pairings regulate alternative splicing of the highly complex 3' variable regions of Drosophila CG42235 and Pip Our findings will facilitate a better understanding of the regulatory mechanisms of highly complex alternative splicing as well as highly variable 3' processing.
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Affiliation(s)
- Huawei Pan
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Yang Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Shuo Chen
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Yun Yang
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Yuan Yue
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Leilei Zhan
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Lanzhi Dai
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Haiyang Dong
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Weiling Hong
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Feng Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Yongfeng Jin
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
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722
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Genome-wide CRISPR-Cas9 Interrogation of Splicing Networks Reveals a Mechanism for Recognition of Autism-Misregulated Neuronal Microexons. Mol Cell 2018; 72:510-524.e12. [DOI: 10.1016/j.molcel.2018.10.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/27/2018] [Accepted: 10/04/2018] [Indexed: 12/22/2022]
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723
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Blue RE, Koushik A, Engels NM, Wiedner HJ, Cooper TA, Giudice J. Modulation of alternative splicing of trafficking genes by genome editing reveals functional consequences in muscle biology. Int J Biochem Cell Biol 2018; 105:134-143. [PMID: 30316870 DOI: 10.1016/j.biocel.2018.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/12/2018] [Accepted: 10/09/2018] [Indexed: 01/22/2023]
Abstract
Alternative splicing is a regulatory mechanism by which multiple mRNA isoforms are generated from single genes. Numerous genes that encode membrane trafficking proteins are alternatively spliced. However, there is limited information about the functional consequences that result from these splicing transitions. Here, we developed appropriate tools to study the functional impact of alternative splicing in development within the most in vivo context. Secondly, we provided evidence of the physiological implications of splicing regulation during muscle development. Our previous work in mouse heart development identified three trafficking genes that are regulated by alternative splicing between birth and adulthood: the clathrin heavy chain, the clathrin light chain-a, and the trafficking kinesin binding protein-1. Here, we demonstrated that alternative splicing regulation of these three genes is tissue- and developmental stage-specific. To identify the functional consequences of splicing regulation in vivo, we used genome editing to block the neonatal-to-adult splicing transitions. We characterized the phenotype of one of these mouse lines and demonstrated that when splicing regulation of the clathrin heavy chain gene is prevented mice exhibit an increase in body and muscle weights which is due to an enlargement in myofiber size. The significance of this work has two components. First, we revealed novel roles of the clathrin heavy chain in muscle growth and showed that its regulation by alternative splicing contributes to muscle development. Second, the new mouse lines will provide a useful tool to study how splicing regulation of three trafficking genes affects tissue identity acquisition and maturation in vivo.
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Affiliation(s)
- R Eric Blue
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Amrita Koushik
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Nichlas M Engels
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Hannah J Wiedner
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Curriculum in Genetics & Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Thomas A Cooper
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, 77030, USA; Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA; Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jimena Giudice
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Curriculum in Genetics & Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; McAllister Heart Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
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724
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PRMT1 Deficiency in Mouse Juvenile Heart Induces Dilated Cardiomyopathy and Reveals Cryptic Alternative Splicing Products. iScience 2018; 8:200-213. [PMID: 30321814 PMCID: PMC6197527 DOI: 10.1016/j.isci.2018.09.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 12/11/2022] Open
Abstract
Protein arginine methyltransferase 1 (PRMT1) catalyzes the asymmetric dimethylation of arginine residues in proteins and methylation of various RNA-binding proteins and is associated with alternative splicing in vitro. Although PRMT1 has essential in vivo roles in embryonic development, CNS development, and skeletal muscle regeneration, the functional importance of PRMT1 in the heart remains to be elucidated. Here, we report that juvenile cardiomyocyte-specific PRMT1-deficient mice develop severe dilated cardiomyopathy and exhibit aberrant cardiac alternative splicing. Furthermore, we identified previously undefined cardiac alternative splicing isoforms of four genes (Asb2, Fbxo40, Nrap, and Eif4a2) in PRMT1-cKO mice and revealed that eIF4A2 protein isoforms translated from alternatively spliced mRNA were differentially ubiquitinated and degraded by the ubiquitin-proteasome system. These findings highlight the essential roles of PRMT1 in cardiac homeostasis and alternative splicing regulation. PRMT1 deficiency in cardiomyocytes causes dilated cardiomyopathy in juvenile mice PRMT1-deficient heart shows abnormal alternative splicing patterns Previously undefined cardiac splicing events are revealed by transcriptome analysis eIF4A2 isoforms are differentially ubiquitinated and degraded
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725
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Merkuri F, Fish JL. Developmental processes regulate craniofacial variation in disease and evolution. Genesis 2018; 57:e23249. [PMID: 30207415 DOI: 10.1002/dvg.23249] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/29/2018] [Accepted: 09/06/2018] [Indexed: 12/30/2022]
Abstract
Variation in development mediates phenotypic differences observed in evolution and disease. Although the mechanisms underlying phenotypic variation are still largely unknown, recent research suggests that variation in developmental processes may play a key role. Developmental processes mediate genotype-phenotype relationships and consequently play an important role regulating phenotypes. In this review, we provide an example of how shared and interacting developmental processes may explain convergence of phenotypes in spliceosomopathies and ribosomopathies. These data also suggest a shared pathway to disease treatment. We then discuss three major mechanisms that contribute to variation in developmental processes: genetic background (gene-gene interactions), gene-environment interactions, and developmental stochasticity. Finally, we comment on evolutionary alterations to developmental processes, and the evolution of disease buffering mechanisms.
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Affiliation(s)
- Fjodor Merkuri
- Department of Biological Sciences, University of Massachusetts Lowell, Lowell, Massachusetts
| | - Jennifer L Fish
- Department of Biological Sciences, University of Massachusetts Lowell, Lowell, Massachusetts
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726
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Sterne-Weiler T, Weatheritt RJ, Best AJ, Ha KC, Blencowe BJ. Efficient and Accurate Quantitative Profiling of Alternative Splicing Patterns of Any Complexity on a Laptop. Mol Cell 2018; 72:187-200.e6. [DOI: 10.1016/j.molcel.2018.08.018] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/24/2018] [Accepted: 08/09/2018] [Indexed: 01/08/2023]
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727
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McGuinness D, Mohammed S, Monaghan L, Wilson PA, Kingsmore DB, Shapter O, Stevenson KS, Coley SM, Devey L, Kirkpatrick RB, Shiels PG. A molecular signature for delayed graft function. Aging Cell 2018; 17:e12825. [PMID: 30094915 PMCID: PMC6156499 DOI: 10.1111/acel.12825] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/08/2018] [Accepted: 07/02/2018] [Indexed: 01/01/2023] Open
Abstract
Chronic kidney disease and associated comorbidities (diabetes, cardiovascular diseases) manifest with an accelerated ageing phenotype, leading ultimately to organ failure and renal replacement therapy. This process can be modulated by epigenetic and environmental factors which promote loss of physiological function and resilience to stress earlier, linking biological age with adverse outcomes post-transplantation including delayed graft function (DGF). The molecular features underpinning this have yet to be fully elucidated. We have determined a molecular signature for loss of resilience and impaired physiological function, via a synchronous genome, transcriptome and proteome snapshot, using human renal allografts as a source of healthy tissue as an in vivo model of ageing in humans. This comprises 42 specific transcripts, related through IFNγ signalling, which in allografts displaying clinically impaired physiological function (DGF) exhibited a greater magnitude of change in transcriptional amplitude and elevated expression of noncoding RNAs and pseudogenes, consistent with increased allostatic load. This was accompanied by increased DNA methylation within the promoter and intragenic regions of the DGF panel in preperfusion allografts with immediate graft function. Pathway analysis indicated that an inability to sufficiently resolve inflammatory responses was enabled by decreased resilience to stress and resulted in impaired physiological function in biologically older allografts. Cross-comparison with publically available data sets for renal pathologies identified significant transcriptional commonality for over 20 DGF transcripts. Our data are clinically relevant and important, as they provide a clear molecular signature for the burden of "wear and tear" within the kidney and thus age-related physiological capability and resilience.
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Affiliation(s)
- Dagmara McGuinness
- Wolfson Wohl Translational Research Centre, Institute of Cancer Sciences, College of Medical, Veterinary & Life Sciences; University of Glasgow; Glasgow UK
| | - Suhaib Mohammed
- Wolfson Wohl Translational Research Centre, Institute of Cancer Sciences, College of Medical, Veterinary & Life Sciences; University of Glasgow; Glasgow UK
| | - Laura Monaghan
- Wolfson Wohl Translational Research Centre, Institute of Cancer Sciences, College of Medical, Veterinary & Life Sciences; University of Glasgow; Glasgow UK
| | - Paul A. Wilson
- Computational Biology; GlaxoSmithKline Medicines Research Centre; Stevenage UK
| | - David B. Kingsmore
- Renal Transplant Unit, NHS Greater Glasgow and Clyde; South Glasgow University Hospital; Glasgow UK
| | - Oliver Shapter
- Wolfson Wohl Translational Research Centre, Institute of Cancer Sciences, College of Medical, Veterinary & Life Sciences; University of Glasgow; Glasgow UK
- Renal Transplant Unit, NHS Greater Glasgow and Clyde; South Glasgow University Hospital; Glasgow UK
| | - Karen S. Stevenson
- Renal Transplant Unit, NHS Greater Glasgow and Clyde; South Glasgow University Hospital; Glasgow UK
| | - Shana M. Coley
- Research Institute of Infection Immunity and Inflammation, College of Medical, Veterinary & Life Sciences; University of Glasgow; Glasgow UK
| | - Luke Devey
- Metabolic Pathways Cardio Therapy Area Unit; GlaxoSmithKline; King of Prussia Pennsylvania
| | | | - Paul G. Shiels
- Wolfson Wohl Translational Research Centre, Institute of Cancer Sciences, College of Medical, Veterinary & Life Sciences; University of Glasgow; Glasgow UK
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728
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Alternative splicing rewires Hippo signaling pathway in hepatocytes to promote liver regeneration. Nat Struct Mol Biol 2018; 25:928-939. [PMID: 30250226 PMCID: PMC6173981 DOI: 10.1038/s41594-018-0129-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/07/2018] [Indexed: 12/29/2022]
Abstract
During liver regeneration, most new hepatocytes arise via self-duplication; yet, the underlying mechanisms that drive hepatocyte proliferation following injury remain poorly defined. By combining high-resolution transcriptome- and polysome-profiling of hepatocytes purified from quiescent and toxin-injured mouse livers, we uncover pervasive alterations in the mRNA translation of metabolic and RNA processing factors, which modulate the protein levels of a set of splicing regulators. Specifically, downregulation of ESRP2 activates a neonatal alternative splicing program that rewires the Hippo signaling pathway in regenerating hepatocytes. We show that production of neonatal splice isoforms attenuates Hippo signaling, enables greater transcriptional activation of downstream target genes, and facilitates liver regeneration. We further demonstrate that ESRP2 deletion in mice causes excessive hepatocyte proliferation upon injury, whereas forced expression of ESRP2 inhibits proliferation by suppressing the expression of neonatal Hippo pathway isoforms. Thus, our findings reveal an ESRP2-Hippo pathway-alternative splicing axis that supports regeneration following chronic liver injury.
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729
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Gallo S, Arcidiacono MV, Tisato V, Piva R, Penolazzi L, Bosi C, Feo CV, Gafà R, Secchiero P. Upregulation of the alternative splicing factor NOVA2 in colorectal cancer vasculature. Onco Targets Ther 2018; 11:6049-6056. [PMID: 30275709 PMCID: PMC6157992 DOI: 10.2147/ott.s171678] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background Tumor-specific isoforms generated by alternative splicing (AS) are demonstrated to contribute to tumor progression and can represent potential biomarkers. NOVA2 is an AS factor that in physiological conditions regulates endothelial cells' (ECs) polarity and vessel lumen maturation, likely by mediating AS of apical-basal polarity regulators. However, NOVA2 expression in tumor ECs and its regulation have never been investigated. Methods To elucidate this, 40 colorectal cancer patients were enrolled and NOVA2 expression was investigated by immunohistochemistry in samples bearing both the normal mucosa and the tumor tissue. Results NOVA2 was found expressed in ECs of tumor vasculature and, importantly, it was upregulated in tumor ECs with respect to normal mucosa ECs in all cases (P<0.001). The same samples analyzed by immunohistochemistry for the expression HIF1α, a marker of hypoxia, showed a positive and significant association with NOVA2 levels (P=0.045). Of note, NOVA2 was upregulated by hypoxia also in an in vitro ECs model. Conclusion Our results provide, for the first time, evidence of NOVA2 expression and upregulation in tumor ECs and highlight hypoxia as a potential regulatory factor. These findings open a completely new perspective to study tumor vasculature and to uncover NOVA2 as a potential source of biomarkers and therapeutic targets based on AS isoforms.
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Affiliation(s)
- Stefania Gallo
- Department of Morphology, Surgery, Experimental Medicine and LTTA Center, University of Ferrara, Ferrara, Italy,
| | | | - Veronica Tisato
- Department of Morphology, Surgery, Experimental Medicine and LTTA Center, University of Ferrara, Ferrara, Italy,
| | - Roberta Piva
- Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, Italy
| | - Letizia Penolazzi
- Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, Italy
| | - Cristina Bosi
- Department of Morphology, Surgery, Experimental Medicine and LTTA Center, University of Ferrara, Ferrara, Italy,
| | - Carlo V Feo
- Department of Morphology, Surgery, Experimental Medicine and LTTA Center, University of Ferrara, Ferrara, Italy,
| | - Roberta Gafà
- Department of Morphology, Surgery, Experimental Medicine and LTTA Center, University of Ferrara, Ferrara, Italy,
| | - Paola Secchiero
- Department of Morphology, Surgery, Experimental Medicine and LTTA Center, University of Ferrara, Ferrara, Italy,
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730
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Werner MS, Sieriebriennikov B, Prabh N, Loschko T, Lanz C, Sommer RJ. Young genes have distinct gene structure, epigenetic profiles, and transcriptional regulation. Genome Res 2018; 28:1675-1687. [PMID: 30232198 PMCID: PMC6211652 DOI: 10.1101/gr.234872.118] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 09/05/2018] [Indexed: 12/22/2022]
Abstract
Species-specific, new, or "orphan" genes account for 10%-30% of eukaryotic genomes. Although initially considered to have limited function, an increasing number of orphan genes have been shown to provide important phenotypic innovation. How new genes acquire regulatory sequences for proper temporal and spatial expression is unknown. Orphan gene regulation may rely in part on origination in open chromatin adjacent to preexisting promoters, although this has not yet been assessed by genome-wide analysis of chromatin states. Here, we combine taxon-rich nematode phylogenies with Iso-Seq, RNA-seq, ChIP-seq, and ATAC-seq to identify the gene structure and epigenetic signature of orphan genes in the satellite model nematode Pristionchus pacificus Consistent with previous findings, we find young genes are shorter, contain fewer exons, and are on average less strongly expressed than older genes. However, the subset of orphan genes that are expressed exhibit distinct chromatin states from similarly expressed conserved genes. Orphan gene transcription is determined by a lack of repressive histone modifications, confirming long-held hypotheses that open chromatin is important for new gene formation. Yet orphan gene start sites more closely resemble enhancers defined by H3K4me1, H3K27ac, and ATAC-seq peaks, in contrast to conserved genes that exhibit traditional promoters defined by H3K4me3 and H3K27ac. Although the majority of orphan genes are located on chromosome arms that contain high recombination rates and repressive histone marks, strongly expressed orphan genes are more randomly distributed. Our results support a model of new gene origination by rare integration into open chromatin near enhancers.
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Affiliation(s)
- Michael S Werner
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Bogdan Sieriebriennikov
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Neel Prabh
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Tobias Loschko
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Christa Lanz
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Ralf J Sommer
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
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731
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Dhamija S, Menon MB. Non-coding transcript variants of protein-coding genes - what are they good for? RNA Biol 2018; 15:1025-1031. [PMID: 30146915 DOI: 10.1080/15476286.2018.1511675] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The total number of protein-coding genes in the human genome is not significantly higher than those in much simpler eukaryotes, despite a general increase in genome size proportionate to the organismal complexity. The large non-coding transcriptome and extensive differential splicing, are increasingly being accepted as the factors contributing to the complex mammalian physiology and architecture. Recent studies reveal additional layers of functional complexity: some long non-coding RNAs have been re-defined as micropeptide or microprotein encoding transcripts, and in turn some protein-coding RNAs are bifunctional and display also non-coding functions. Moreover, several protein-coding genes express long non-coding RNA splice-forms and generate circular RNAs in addition to their canonical mRNA transcripts, revoking the strict definition of a gene as coding or non-coding. In this mini review, we discuss the current understanding of these hybrid genes and their possible roles and relevance.
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Affiliation(s)
- Sonam Dhamija
- a Division of Cancer Research, Department of Thoracic Surgery , Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg , Freiburg , Germany.,b Division of RNA Biology & Cancer , German Cancer Research Center (DKFZ) , Heidelberg , Germany
| | - Manoj B Menon
- c Institute of Cell Biochemistry , Hannover Medical School , Hannover , Germany
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732
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Alvelos MI, Juan-Mateu J, Colli ML, Turatsinze JV, Eizirik DL. When one becomes many-Alternative splicing in β-cell function and failure. Diabetes Obes Metab 2018; 20 Suppl 2:77-87. [PMID: 30230174 PMCID: PMC6148369 DOI: 10.1111/dom.13388] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/22/2018] [Accepted: 05/30/2018] [Indexed: 12/20/2022]
Abstract
Pancreatic β-cell dysfunction and death are determinant events in type 1 diabetes (T1D), but the molecular mechanisms behind β-cell fate remain poorly understood. Alternative splicing is a post-transcriptional mechanism by which a single gene generates different mRNA and protein isoforms, expanding the transcriptome complexity and enhancing protein diversity. Neuron-specific and certain serine/arginine-rich RNA binding proteins (RBP) are enriched in β-cells, playing crucial roles in the regulation of insulin secretion and β-cell survival. Moreover, alternative exon networks, regulated by inflammation or diabetes susceptibility genes, control key pathways and processes for the correct function and survival of β-cells. The challenge ahead of us is to understand the precise role of alternative splicing regulators and splice variants on β-cell function, dysfunction and death and develop tools to modulate it.
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Affiliation(s)
- Maria Inês Alvelos
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
| | - Jonàs Juan-Mateu
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
| | - Maikel Luis Colli
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
| | - Jean-Valéry Turatsinze
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
| | - Décio L. Eizirik
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
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733
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Abstract
During erythropoiesis, hematopoietic stem and progenitor cells transition to erythroblasts en route to terminal differentiation into enucleated red blood cells. Transcriptome-wide changes underlie distinct morphological and functional characteristics at each cell division during this process. Many studies of gene expression have historically been carried out in erythroblasts, and the biogenesis of β-globin mRNA—the most highly expressed transcript in erythroblasts—was the focus of many seminal studies on the mechanisms of pre-mRNA splicing. We now understand that pre-mRNA splicing plays an important role in shaping the transcriptome of developing erythroblasts. Recent advances have provided insight into the role of alternative splicing and intron retention as important regulatory mechanisms of erythropoiesis. However, dysregulation of splicing during erythropoiesis is also a cause of several hematological diseases, including β-thalassemia and myelodysplastic syndromes. With a growing understanding of the role that splicing plays in these diseases, we are well poised to develop gene-editing treatments. In this review, we focus on changes in the developing erythroblast transcriptome caused by alternative splicing, the molecular basis of splicing-related blood diseases, and therapeutic advances in disease treatment using CRISPR/Cas9 gene editing.
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Affiliation(s)
- Kirsten A Reimer
- Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, 06520, USA
| | - Karla M Neugebauer
- Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, 06520, USA
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734
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Signor S, Nuzhdin S. Dynamic changes in gene expression and alternative splicing mediate the response to acute alcohol exposure in Drosophila melanogaster. Heredity (Edinb) 2018; 121:342-360. [PMID: 30143789 DOI: 10.1038/s41437-018-0136-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/21/2018] [Accepted: 07/19/2018] [Indexed: 12/18/2022] Open
Abstract
Environmental changes typically cause rapid gene expression responses in the exposed organisms, including changes in the representation of gene isoforms with different functions or properties. Identifying the genes that respond to environmental change, including in genotype-specific ways, is an important step in treating the undesirable physiological effects of stress, such as exposure to toxins or ethanol. Ethanol is a unique environmental stress in that chronic exposure results in permanent physiological changes and the development of alcohol use disorders. Drosophila is a classic model for deciphering the mechanisms of the response to alcohol exposure, as it meets the criteria for the development of alcohol use disorders, and has similar physiological underpinnings with vertebrates. Because many studies on the response to ethanol have relied on a priori candidate genes, broad surveys of gene expression and splicing are required and have been investigated here. Further, we expose Drosophila to ethanol in an environment that is genetically, socially, and ecologically relevant. Both expression and splicing differences, inasmuch as they can be decomposed, contribute to the response to ethanol in Drosophila melanogaster. However, we find that while D. melanogaster responds to ethanol, there is very little genetic variation in how it responds to ethanol. In addition, the response to alcohol over time is dynamic, suggesting that incorporating time into studies on the response to the environment is important.
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Affiliation(s)
- Sarah Signor
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA.
| | - Sergey Nuzhdin
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
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735
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Gao Y, Vasic R, Halene S. Role of alternative splicing in hematopoietic stem cells during development. Stem Cell Investig 2018; 5:26. [PMID: 30221171 DOI: 10.21037/sci.2018.08.02] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 08/13/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Yimeng Gao
- Section of Hematology, Department of Internal Medicine and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Radovan Vasic
- Section of Hematology, Department of Internal Medicine and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Stephanie Halene
- Section of Hematology, Department of Internal Medicine and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06511, USA
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736
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Braun S, Enculescu M, Setty ST, Cortés-López M, de Almeida BP, Sutandy FXR, Schulz L, Busch A, Seiler M, Ebersberger S, Barbosa-Morais NL, Legewie S, König J, Zarnack K. Decoding a cancer-relevant splicing decision in the RON proto-oncogene using high-throughput mutagenesis. Nat Commun 2018; 9:3315. [PMID: 30120239 PMCID: PMC6098099 DOI: 10.1038/s41467-018-05748-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 07/19/2018] [Indexed: 01/22/2023] Open
Abstract
Mutations causing aberrant splicing are frequently implicated in human diseases including cancer. Here, we establish a high-throughput screen of randomly mutated minigenes to decode the cis-regulatory landscape that determines alternative splicing of exon 11 in the proto-oncogene MST1R (RON). Mathematical modelling of splicing kinetics enables us to identify more than 1000 mutations affecting RON exon 11 skipping, which corresponds to the pathological isoform RON∆165. Importantly, the effects correlate with RON alternative splicing in cancer patients bearing the same mutations. Moreover, we highlight heterogeneous nuclear ribonucleoprotein H (HNRNPH) as a key regulator of RON splicing in healthy tissues and cancer. Using iCLIP and synergy analysis, we pinpoint the functionally most relevant HNRNPH binding sites and demonstrate how cooperative HNRNPH binding facilitates a splicing switch of RON exon 11. Our results thereby offer insights into splicing regulation and the impact of mutations on alternative splicing in cancer.
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Affiliation(s)
- Simon Braun
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Mihaela Enculescu
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Samarth T Setty
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt, Germany
| | | | - Bernardo P de Almeida
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028, Lisboa, Portugal.,Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Campus Gambelas, 8005-139, Faro, Portugal
| | | | - Laura Schulz
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Anke Busch
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Markus Seiler
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt, Germany
| | | | - Nuno L Barbosa-Morais
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028, Lisboa, Portugal
| | - Stefan Legewie
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany.
| | - Julian König
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany.
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt, Germany.
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737
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Gapinske M, Luu A, Winter J, Woods WS, Kostan KA, Shiva N, Song JS, Perez-Pinera P. CRISPR-SKIP: programmable gene splicing with single base editors. Genome Biol 2018; 19:107. [PMID: 30107853 PMCID: PMC6092781 DOI: 10.1186/s13059-018-1482-5] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 07/13/2018] [Indexed: 01/09/2023] Open
Abstract
CRISPR gene editing has revolutionized biomedicine and biotechnology by providing a simple means to engineer genes through targeted double-strand breaks in the genomic DNA of living cells. However, given the stochasticity of cellular DNA repair mechanisms and the potential for off-target mutations, technologies capable of introducing targeted changes with increased precision, such as single-base editors, are preferred. We present a versatile method termed CRISPR-SKIP that utilizes cytidine deaminase single-base editors to program exon skipping by mutating target DNA bases within splice acceptor sites. Given its simplicity and precision, CRISPR-SKIP will be broadly applicable in gene therapy and synthetic biology.
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Affiliation(s)
- Michael Gapinske
- Department of Bioengineering, University of Illinois at Urbana-Champaign, 1406 West Green Street, Urbana, 61801-2918 IL USA
| | - Alan Luu
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801-3080 USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Jackson Winter
- Department of Bioengineering, University of Illinois at Urbana-Champaign, 1406 West Green Street, Urbana, 61801-2918 IL USA
| | - Wendy S. Woods
- Department of Bioengineering, University of Illinois at Urbana-Champaign, 1406 West Green Street, Urbana, 61801-2918 IL USA
| | - Kurt A. Kostan
- Department of Bioengineering, University of Illinois at Urbana-Champaign, 1406 West Green Street, Urbana, 61801-2918 IL USA
| | - Nikhil Shiva
- Department of Bioengineering, University of Illinois at Urbana-Champaign, 1406 West Green Street, Urbana, 61801-2918 IL USA
| | - Jun S. Song
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801-3080 USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Pablo Perez-Pinera
- Department of Bioengineering, University of Illinois at Urbana-Champaign, 1406 West Green Street, Urbana, 61801-2918 IL USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- Carle Illinois College of Medicine, Champaign, IL 61820 USA
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738
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Lin P, He RQ, Ma FC, Liang L, He Y, Yang H, Dang YW, Chen G. Systematic Analysis of Survival-Associated Alternative Splicing Signatures in Gastrointestinal Pan-Adenocarcinomas. EBioMedicine 2018; 34:46-60. [PMID: 30131306 PMCID: PMC6116578 DOI: 10.1016/j.ebiom.2018.07.040] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/29/2018] [Accepted: 07/31/2018] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Gastrointestinal pan-adenocarcinomas, which mainly include adenocarcinomas of the esophagus, stomach, colon, and rectum, place a heavy burden on society owing to their poor prognoses. Since aberrant alternative splicing (AS) are starting to be considered as efficacious signatures for tumor prognosis predicting and therapeutic targets, systematic analysis of AS events is urgent. METHODS Prognosis-related AS events were selected by using univariate COX regression analysis. Gene functional enrichment analysis revealed the pathways enriched by prognosis-related AS. Then, prognostic signatures based on AS events were developed for prognosis prediction. Potential mechanism to regulate splicing events by splicing factors was analyzed via Pearson correlation and regulatory networks were constructed. FINDINGS A total of 967, 918, 674, and 406 AS events were identified as prognosis-related AS events in esophagus, stomach, colon, and rectum adenocarcinomas, respectively. Survival-associated AS events were distinguishing in the four subtypes of adenocarcinoma. Furthermore, computational algorithm results indicated that perturbation of ribosome and ubiquitin-mediated proteolysis pathways were the potential molecular mechanisms corresponding to inferior prognoses. Most notably, several prognostic signatures based on AS events displayed moderate performance in prognosis predicting. The area under curve values of the time-dependent receiver operating characteristic were 0.961, 0.871, 0.870, and 0.890 in esophagus, stomach, colon, and rectum adenocarcinomas. Survival-associated splicing factors were submitted to construct the AS regulatory network, which could be an underlying mechanism of AS events. INTERPRETATION AS may could be ideal indiactors in the prognosis of gastrointestinal pan-adenocarcinomas. Exploring interesting splicing regulatory networks is conducive to solve the puzzles of AS.
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Affiliation(s)
- Peng Lin
- Department of Medical Ultrasonics, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, PR China
| | - Rong-Quan He
- Department of Medical Oncology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, PR China
| | - Fu-Chao Ma
- Department of Medical Oncology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, PR China
| | - Liang Liang
- Department of General Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, PR China
| | - Yun He
- Department of Medical Ultrasonics, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, PR China
| | - Hong Yang
- Department of Medical Ultrasonics, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, PR China
| | - Yi-Wu Dang
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, PR China
| | - Gang Chen
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, PR China.
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739
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Kaur G, Helmer RA, Smith LA, Martinez-Zaguilan R, Dufour JM, Chilton BS. Alternative splicing of helicase-like transcription factor (Hltf): Intron retention-dependent activation of immune tolerance at the feto-maternal interface. PLoS One 2018; 13:e0200211. [PMID: 29975766 PMCID: PMC6033450 DOI: 10.1371/journal.pone.0200211] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/21/2018] [Indexed: 12/21/2022] Open
Abstract
Hltf is regulated by intron retention, and global Hltf-deletion causes perinatal lethality from hypoglycemia. In heart, full-length Hltf is a transcriptional regulator of Hif-1α that controls transport systems. Thus, we tested the hypothesis that Hltf deletion from placenta caused or exacerbated neonatal hypoglycemia via Hif-1α regulation of nutrient transporters. RNA-seq data analyses identified significant changes in transcript expression and alternative splicing (AS) in E18.5 placentome. iPathwayGuide was used for gene ontology (GO) analysis of biological processes, molecular functions and cellular components. Elim pruning algorithm identified hierarchical relationships. The methylome was interrogated by Methyl-MiniSeq Epiquest analysis. GO analysis identified gene enrichment within biological processes. Protein expression was visualized with immunohistochemistry. Although two Hltf mRNA isoforms are quantifiable in most murine tissues, only the truncated Hltf isoform is expressed in placenta. The responsible intron retention event occurs in the absence of DNA methylation. iPathwayGuide analysis identified 157 target genes of 11,538 total genes with measured expression. These were obtained using a threshold of 0.05 for statistical significance (p-value) and a long fold change of expression with absolute value of at least 0.6. Hltf deletion altered transcription of trophoblast lineage-specific genes, and increased transcription of the Cxcr7 (p = 0.004) gene whose protein product is a co-receptor for human and simian immunodeficiency viruses. Concomitant increased Cxcr7 protein was identified with immunolabeling. Hltf deletion had no effect on transcription or site-specific methylation patterns of Hif-1α, the major glucose transporters, or System A amino acid transporters. There was no measureable evidence of uteroplacental dysfunction or fetal compromise. iPathGuide analysis revealed Hltf suppresses cytolysis (10/21 genes; p-value 1.900e-12; p-value correction: Elim pruning; GO:019835) including the perforin-granzyme pathway in uterine natural killer cells. Our findings 1) prove the truncated Hltf protein isoform is a transcription factor, 2) establish a functional link between AS of Hltf and immunosuppression at the feto-maternal interface, 3) correlate intron retention with the absence of DNA methylation, and 4) underscore the importance of differential splicing analysis to identify Hltf's functional diversity.
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Affiliation(s)
- Gurvinder Kaur
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Rebecca A. Helmer
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Lisa A. Smith
- Department of Pathology, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Raul Martinez-Zaguilan
- Department of Cell Physiology & Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Jannette M. Dufour
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Beverly S. Chilton
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
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740
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Williams AL, Khadka V, Tang M, Avelar A, Schunke KJ, Menor M, Shohet RV. HIF1 mediates a switch in pyruvate kinase isoforms after myocardial infarction. Physiol Genomics 2018; 50:479-494. [PMID: 29652636 PMCID: PMC6087881 DOI: 10.1152/physiolgenomics.00130.2017] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/05/2018] [Accepted: 04/09/2018] [Indexed: 12/20/2022] Open
Abstract
Alternative splicing of RNA is an underexplored area of transcriptional response. We expect that early changes in alternatively spliced genes may be important for responses to cardiac injury. Hypoxia inducible factor 1 (HIF1) is a key transcription factor that rapidly responds to loss of oxygen through alteration of metabolism and angiogenesis. The goal of this study was to investigate the transcriptional response after myocardial infarction (MI) and to identify novel, hypoxia-driven changes, including alternative splicing. After ligation of the left anterior descending artery in mice, we observed an abrupt loss of cardiac contractility and upregulation of hypoxic signaling. We then performed RNA sequencing on ischemic heart tissue 1 and 3 days after infarct to assess early transcriptional changes and identified 89 transcripts with altered splicing. Of particular interest was the switch in Pkm isoform expression (pyruvate kinase, muscle). The usually predominant Pkm1 isoform was less abundant in ischemic hearts, while Pkm2 and associated splicing factors (hnRNPA1, hnRNPA2B1, Ptbp1) rapidly increased. Despite increased Pkm2 expression, total pyruvate kinase activity remained reduced in ischemic myocardial tissue. We also demonstrated HIF1 binding to PKM by chromatin immunoprecipitation, indicating a direct role for HIF1 in mediating this isoform switch. Our study provides a new, detailed characterization of the early transcriptome after MI. From this analysis, we identified an HIF1-mediated alternative splicing event in the PKM gene. Pkm1 and Pkm2 play distinct roles in glycolytic metabolism and the upregulation of Pkm2 is likely to have important consequences for ATP synthesis in infarcted cardiac muscle.
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Affiliation(s)
- Allison Lesher Williams
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii , Honolulu, Hawaii
| | - Vedbar Khadka
- Bioinformatics Core, John A. Burns School of Medicine, University of Hawaii , Honolulu, Hawaii
| | - Mingxin Tang
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii , Honolulu, Hawaii
| | - Abigail Avelar
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii , Honolulu, Hawaii
| | - Kathryn J Schunke
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii , Honolulu, Hawaii
| | - Mark Menor
- Bioinformatics Core, John A. Burns School of Medicine, University of Hawaii , Honolulu, Hawaii
| | - Ralph V Shohet
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii , Honolulu, Hawaii
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741
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Pendleton KE, Park SK, Hunter OV, Bresson SM, Conrad NK. Balance between MAT2A intron detention and splicing is determined cotranscriptionally. RNA (NEW YORK, N.Y.) 2018; 24:778-786. [PMID: 29563249 PMCID: PMC5959247 DOI: 10.1261/rna.064899.117] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 03/16/2018] [Indexed: 05/22/2023]
Abstract
Transcriptome analysis of human cells has revealed that intron retention controls the expression of a large number of genes with diverse cellular functions. Detained introns (DI) constitute a subgroup of transcripts with retained introns that are not exported to the cytoplasm but instead remain in the nucleus. Previous studies reported that the splicing of DIs in the CLK1 transcript is post-transcriptionally induced to produce mature mRNA in the absence of new transcription. Thus, CLK1-DI serves as a precursor or "reservoir" for the CLK1 mRNA. However, whether this is a universal mechanism for gene regulation by intron detention remains unknown. The MAT2A gene encodes S-adenosylmethionine (SAM) synthetase and it contains a DI that is regulated in response to intracellular SAM levels. We used three independent assays to assess the precursor-product relationship between MAT2A-DI and MAT2A mRNA. In contrast to CLK1-DI, these data support a model in which the MAT2A-DI transcript is not a precursor to mRNA but is instead a "dead-end" RNA fated for nuclear decay. Additionally, we show that in SAM-deprived conditions the cotranscriptional splicing of MAT2A detained introns increases. We conclude that polyadenylated RNAs with DIs can have at least two distinct fates. They can serve as nuclear reservoirs of pre-mRNAs available for rapid induction by the cell, or they constitute dead-end RNAs that are degraded in the nucleus.
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Affiliation(s)
- Kathryn E Pendleton
- Department of Microbiology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Sung-Kyun Park
- Department of Microbiology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Olga V Hunter
- Department of Microbiology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Stefan M Bresson
- Department of Microbiology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Nicholas K Conrad
- Department of Microbiology, UT Southwestern Medical Center, Dallas, Texas 75390, USA
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742
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Dynamic transcriptomic m 6A decoration: writers, erasers, readers and functions in RNA metabolism. Cell Res 2018; 28:616-624. [PMID: 29789545 PMCID: PMC5993786 DOI: 10.1038/s41422-018-0040-8] [Citation(s) in RCA: 911] [Impact Index Per Article: 151.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 04/22/2018] [Indexed: 02/06/2023] Open
Abstract
N6-methyladenosine (m6A) is a chemical modification present in multiple RNA species, being most abundant in mRNAs. Studies on enzymes or factors that catalyze, recognize, and remove m6A have revealed its comprehensive roles in almost every aspect of mRNA metabolism, as well as in a variety of physiological processes. This review describes the current understanding of the m6A modification, particularly the functions of its writers, erasers, readers in RNA metabolism, with an emphasis on its role in regulating the isoform dosage of mRNAs.
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743
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Blue RE, Curry EG, Engels NM, Lee EY, Giudice J. How alternative splicing affects membrane-trafficking dynamics. J Cell Sci 2018; 131:jcs216465. [PMID: 29769303 PMCID: PMC6031328 DOI: 10.1242/jcs.216465] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The cell biology field has outstanding working knowledge of the fundamentals of membrane-trafficking pathways, which are of critical importance in health and disease. Current challenges include understanding how trafficking pathways are fine-tuned for specialized tissue functions in vivo and during development. In parallel, the ENCODE project and numerous genetic studies have revealed that alternative splicing regulates gene expression in tissues and throughout development at a post-transcriptional level. This Review summarizes recent discoveries demonstrating that alternative splicing affects tissue specialization and membrane-trafficking proteins during development, and examines how this regulation is altered in human disease. We first discuss how alternative splicing of clathrin, SNAREs and BAR-domain proteins influences endocytosis, secretion and membrane dynamics, respectively. We then focus on the role of RNA-binding proteins in the regulation of splicing of membrane-trafficking proteins in health and disease. Overall, our aim is to comprehensively summarize how trafficking is molecularly influenced by alternative splicing and identify future directions centered on its physiological relevance.
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Affiliation(s)
- R Eric Blue
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ennessa G Curry
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nichlas M Engels
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Eunice Y Lee
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jimena Giudice
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- McAllister Heart Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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744
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Wu DR, Gu KL, Yu JC, Fu X, Wang XW, Guo WT, Liao LQ, Zhu H, Zhang XS, Hui J, Wang Y. Opposing roles of miR-294 and MBNL1/2 in shaping the gene regulatory network of embryonic stem cells. EMBO Rep 2018; 19:embr.201745657. [PMID: 29735517 DOI: 10.15252/embr.201745657] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 01/25/2023] Open
Abstract
Alternative pre-mRNA splicing plays important roles in regulating self-renewal and differentiation of embryonic stem cells (ESCs). However, how specific alternative splicing programs are established in ESCs remains elusive. Here, we show that a subset of alternative splicing events in ESCs is dependent on miR-294 expression. Remarkably, roughly 60% of these splicing events are affected by the depletion of Muscleblind-Like Splicing Regulator 1 and 2 (Mbnl1/2). Distinct from canonical miRNA function, miR-294 represses Mbnl1/2 through both posttranscriptional and epigenetic mechanisms. Furthermore, we uncover non-canonical functions of MBNL proteins that bind and promote the expression of miR-294 targets, including Cdkn1a and Tgfbr2, thereby opposing the role of miR-294 in regulating cell proliferation, apoptosis, and epithelial-mesenchymal transition (EMT). Our study reveals extensive interactions between miRNAs and splicing factors, highlighting their roles in regulating cell type-specific alternative splicing and defining gene expression programs during development and cellular differentiation.
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Affiliation(s)
- Da-Ren Wu
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Kai-Li Gu
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Jian-Cheng Yu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Xing Fu
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
| | - Xi-Wen Wang
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Wen-Ting Guo
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Le-Qi Liao
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Hong Zhu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Xiao-Shan Zhang
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Jingyi Hui
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yangming Wang
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
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745
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Xie Y, Wang X. Comparative transcriptomic analysis identifies genes responsible for fruit count and oil yield in the oil tea plant Camellia chekiangoleosa. Sci Rep 2018; 8:6637. [PMID: 29703942 PMCID: PMC5923238 DOI: 10.1038/s41598-018-24073-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 03/21/2018] [Indexed: 12/02/2022] Open
Abstract
Fruit yield is an important trait for horticultural crops. However, the limited fruit yield of Camellia chekiangoleosa, a novel promising oil tree, restricts the production of oil. The breeding improvement is little due to its long generation time and lack of available genomic sequence. We identified distinct fruit count phenotypes, high-yield (HY) and low-yield (LY). To understand the underlying genetic basis, we focused on global gene discovery and expression levels in floral buds, which affect fruit count. A total of 140,299 de novo assembled unigenes were obtained using RNA-seq technology, and more genes were expressed in HY than in LY. 2395 differentially expressed genes (DEGs) were identified and enriched in membrane, energy metabolism, secondary metabolism, fatty acid biosynthesis and metabolism, and 18 other metabolic pathways. Of the DEGs, twelve identified transcription factors, including AP2, mostly involve in inflorescence and flower development and in hormone networks. Key DEGs in fatty acid biosynthesis (Fab) FabB, FabF, FabZ, and AccD were highly expressed in floral buds and associated with high oil yield in fruits. We hypothesized that a potential link exists between fruit count and its oil yield. These findings help to elucidate the molecular cues affecting fruit count and oil yield.
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Affiliation(s)
- Yun Xie
- Jiyang College, Zhejiang A&F University, Zhuji, Zhejiang, 311800, China
| | - Xuewen Wang
- Department of Genetics, University of Georgia, Athens, 30602, USA.
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746
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Lu X, Zhao ZA, Wang X, Zhang X, Zhai Y, Deng W, Yi Z, Li L. Whole-transcriptome splicing profiling of E7.5 mouse primary germ layers reveals frequent alternative promoter usage during mouse early embryogenesis. Biol Open 2018; 7:7/3/bio032508. [PMID: 29592913 PMCID: PMC5898269 DOI: 10.1242/bio.032508] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Alternative splicing (AS) and alternative promoter (AP) usage expand the repertories of mammalian transcriptome profiles and thus diversify gene functions. However, our knowledge about the extent and functions of AS and AP usage in mouse early embryogenesis remains elusive. Here, by performing whole-transcriptome splicing profiling with high-throughput next generation sequencing, we report that AS extensively occurs in embryonic day (E) 7.5 mouse primary germ layers, and may be involved in multiple developmental processes. In addition, numerous RNA splicing factors are differentially expressed and alternatively spliced across the three germ layers, implying the potential importance of AS machinery in shaping early embryogenesis. Notably, AP usage is remarkably frequent at this stage, accounting for more than one quarter (430/1,648) of the total significantly different AS events. Genes generating the 430 AP events participate in numerous biological processes, and include important regulators essential for mouse early embryogenesis, suggesting that AP usage is widely used and might be relevant to mouse germ layer specification. Our data underline the potential significance of AP usage in mouse gastrulation, providing a rich data source and opening another dimension for understanding the regulatory mechanisms of mammalian early development. Summary: This study seeks to capture the alternative splicing landscape during mouse gastrulation, underlining the potential importance of alternative promoter usage in mammalian early embryogenesis.
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Affiliation(s)
- Xukun Lu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen-Ao Zhao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaoqing Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaoxin Zhang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanhua Zhai
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenbo Deng
- Division of Reproductive Sciences, Cincinnati Children's Hospital Medical, Cincinnati, OH 45229, USA
| | - Zhaohong Yi
- Key Laboratory of Urban Agriculture (North) of Ministry of Agriculture, College of Biological Science and Engineering, Beijing University of Agriculture, Beijing 102206, China
| | - Lei Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China .,University of Chinese Academy of Sciences, Beijing 100049, China
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747
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748
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Alternative mRNA Splicing in the Pathogenesis of Obesity. Int J Mol Sci 2018; 19:ijms19020632. [PMID: 29473878 PMCID: PMC5855854 DOI: 10.3390/ijms19020632] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 12/22/2022] Open
Abstract
Alternative mRNA splicing is an important mechanism in expansion of proteome diversity by production of multiple protein isoforms. However, emerging evidence indicates that only a limited number of annotated protein isoforms by alternative splicing are detected, and the coding sequence of alternative splice variants usually is only slightly different from that of the canonical sequence. Nevertheless, mis-splicing is associated with a large array of human diseases. Previous reviews mainly focused on hereditary and somatic mutations in cis-acting RNA sequence elements and trans-acting splicing factors. The importance of environmental perturbations contributed to mis-splicing is not assessed. As significant changes in exon skipping and splicing factors expression levels are observed with diet-induced obesity, this review focuses on several well-known alternatively spliced metabolic factors and discusses recent advances in the regulation of the expressions of splice variants under the pathophysiological conditions of obesity. The potential of targeting the alternative mRNA mis-splicing for obesity-associated diseases therapies will also be discussed.
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Su CH, D D, Tarn WY. Alternative Splicing in Neurogenesis and Brain Development. Front Mol Biosci 2018; 5:12. [PMID: 29484299 PMCID: PMC5816070 DOI: 10.3389/fmolb.2018.00012] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/25/2018] [Indexed: 12/20/2022] Open
Abstract
Alternative splicing of precursor mRNA is an important mechanism that increases transcriptomic and proteomic diversity and also post-transcriptionally regulates mRNA levels. Alternative splicing occurs at high frequency in brain tissues and contributes to every step of nervous system development, including cell-fate decisions, neuronal migration, axon guidance, and synaptogenesis. Genetic manipulation and RNA sequencing have provided insights into the molecular mechanisms underlying the effects of alternative splicing in stem cell self-renewal and neuronal fate specification. Timely expression and perhaps post-translational modification of neuron-specific splicing regulators play important roles in neuronal development. Alternative splicing of many key transcription regulators or epigenetic factors reprograms the transcriptome and hence contributes to stem cell fate determination. During neuronal differentiation, alternative splicing also modulates signaling activity, centriolar dynamics, and metabolic pathways. Moreover, alternative splicing impacts cortical lamination and neuronal development and function. In this review, we focus on recent progress toward understanding the contributions of alternative splicing to neurogenesis and brain development, which has shed light on how splicing defects may cause brain disorders and diseases.
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Affiliation(s)
- Chun-Hao Su
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Dhananjaya D
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
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Impact, Characterization, and Rescue of Pre-mRNA Splicing Mutations in Lysosomal Storage Disorders. Genes (Basel) 2018; 9:genes9020073. [PMID: 29415500 PMCID: PMC5852569 DOI: 10.3390/genes9020073] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/19/2018] [Accepted: 01/31/2018] [Indexed: 11/16/2022] Open
Abstract
Lysosomal storage disorders (LSDs) represent a group of more than 50 severe metabolic diseases caused by the deficiency of specific lysosomal hydrolases, activators, carriers, or lysosomal integral membrane proteins, leading to the abnormal accumulation of substrates within the lysosomes. Numerous mutations have been described in each disease-causing gene; among them, about 5-19% affect the pre-mRNA splicing process. In the last decade, several strategies to rescue/increase normal splicing of mutated transcripts have been developed and LSDs represent excellent candidates for this type of approach: (i) most of them are inherited in an autosomic recessive manner and patients affected by late-onset (LO) phenotypes often retain a fair amount of residual enzymatic activity; thus, even a small recovery of normal splicing may be beneficial in clinical settings; (ii) most LSDs still lack effective treatments or are currently treated with extremely expensive approaches; (iii) in few LSDs, a single splicing mutation accounts for up to 40-70% of pathogenic alleles. At present, numerous preclinical studies support the feasibility of reverting the pathological phenotype by partially rescuing splicing defects in LSDs. This review provides an overview of the impact of splicing mutations in LSDs and the related therapeutic approaches currently under investigation in these disorders.
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