1
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De Silva N, Lehman N, Fargason T, Paul T, Zhang Z, Zhang J. Unearthing a novel function of SRSF1 in binding and unfolding of RNA G-quadruplexes. Nucleic Acids Res 2024; 52:4676-4690. [PMID: 38567732 PMCID: PMC11077049 DOI: 10.1093/nar/gkae213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 02/28/2024] [Accepted: 03/13/2024] [Indexed: 04/14/2024] Open
Abstract
SRSF1 governs splicing of over 1500 mRNA transcripts. SRSF1 contains two RNA-recognition motifs (RRMs) and a C-terminal Arg/Ser-rich region (RS). It has been thought that SRSF1 RRMs exclusively recognize single-stranded exonic splicing enhancers, while RS lacks RNA-binding specificity. With our success in solving the insolubility problem of SRSF1, we can explore the unknown RNA-binding landscape of SRSF1. We find that SRSF1 RS prefers purine over pyrimidine. Moreover, SRSF1 binds to the G-quadruplex (GQ) from the ARPC2 mRNA, with both RRMs and RS being crucial. Our binding assays show that the traditional RNA-binding sites on the RRM tandem and the Arg in RS are responsible for GQ binding. Interestingly, our FRET and circular dichroism data reveal that SRSF1 unfolds the ARPC2 GQ, with RS leading unfolding and RRMs aiding. Our saturation transfer difference NMR results discover that Arg residues in SRSF1 RS interact with the guanine base but not other nucleobases, underscoring the uniqueness of the Arg/guanine interaction. Our luciferase assays confirm that SRSF1 can alleviate the inhibitory effect of GQ on gene expression in the cell. Given the prevalence of RNA GQ and SR proteins, our findings unveil unexplored SR protein functions with broad implications in RNA splicing and translation.
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Affiliation(s)
- Naiduwadura Ivon Upekala De Silva
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL 35294-1240, USA
| | - Nathan Lehman
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL 35294-1240, USA
| | - Talia Fargason
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL 35294-1240, USA
| | - Trenton Paul
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL 35294-1240, USA
| | - Zihan Zhang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL 35294-1240, USA
| | - Jun Zhang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL 35294-1240, USA
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2
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Sudhakar SRN, Khan SN, Clark A, Hendrickson-Rebizant T, Patel S, Lakowski TM, Davie JR. Protein arginine methyltransferase 1, a major regulator of biological processes. Biochem Cell Biol 2024; 102:106-126. [PMID: 37922507 DOI: 10.1139/bcb-2023-0212] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2023] Open
Abstract
Protein arginine methyltransferase 1 (PRMT1) is a major type I arginine methyltransferase that catalyzes the formation of monomethyl and asymmetric dimethylarginine in protein substrates. It was first identified to asymmetrically methylate histone H4 at the third arginine residue forming the H4R3me2a active histone mark. However, several protein substrates are now identified as being methylated by PRMT1. As a result of its association with diverse classes of substrates, PRMT1 regulates several biological processes like chromatin dynamics, transcription, RNA processing, and signal transduction. The review provides an overview of PRMT1 structure, biochemical features, specificity, regulation, and role in cellular functions. We discuss the genomic distribution of PRMT1 and its association with tRNA genes. Further, we explore the different substrates of PRMT1 involved in splicing. In the end, we discuss the proteins that interact with PRMT1 and their downstream effects in diseased states.
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Affiliation(s)
- Sadhana R N Sudhakar
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, MB, Canada
| | - Shahper N Khan
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, MB, Canada
| | - Ariel Clark
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, MB, Canada
| | | | - Shrinal Patel
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, MB, Canada
| | - Ted M Lakowski
- College of Pharmacy Pharmaceutical Analysis Laboratory, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Paul Albrechtsen Research Institute, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada
| | - James R Davie
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, MB, Canada
- Paul Albrechtsen Research Institute, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada
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3
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Gregorich ZR, Yanghai Z, Kamp TJ, Granzier H, Guo W. Mechanisms of RBM20 Cardiomyopathy: Insights From Model Systems. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2024; 17:e004355. [PMID: 38288598 PMCID: PMC10923161 DOI: 10.1161/circgen.123.004355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2024]
Abstract
RBM20 (RNA-binding motif protein 20) is a vertebrate- and muscle-specific RNA-binding protein that belongs to the serine-arginine-rich family of splicing factors. The RBM20 gene was first identified as a dilated cardiomyopathy-linked gene over a decade ago. Early studies in Rbm20 knockout rodents implicated disrupted splicing of RBM20 target genes as a causative mechanism. Clinical studies show that pathogenic variants in RBM20 are linked to aggressive dilated cardiomyopathy with early onset heart failure and high mortality. Subsequent studies employing pathogenic variant knock-in animal models revealed that variants in a specific portion of the arginine-serine-rich domain in RBM20 not only disrupt splicing but also hinder nucleocytoplasmic transport and lead to the formation of RBM20 biomolecular condensates in the sarcoplasm. Conversely, mice harboring a disease-associated variant in the RRM (RNA recognition motif) do not show evidence of adverse remodeling or exhibit sudden death despite disrupted splicing of RBM20 target genes. Thus, whether disrupted splicing, biomolecular condensates, or both contribute to dilated cardiomyopathy is under debate. Beyond this, additional questions remain, such as whether there is sexual dimorphism in the presentation of RBM20 cardiomyopathy. What are the clinical features of RBM20 cardiomyopathy and why do some individuals develop more severe disease than others? In this review, we summarize the reported observations and discuss potential mechanisms of RBM20 cardiomyopathy derived from studies employing in vivo animal models and in vitro human-induced pluripotent stem cell-derived cardiomyocytes. Potential therapeutic strategies to treat RBM20 cardiomyopathy are also discussed.
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Affiliation(s)
- Zachery R. Gregorich
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI
| | - Zhang Yanghai
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI
| | - Timothy J. Kamp
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
- Cardiovascular Research Center, University of Wisconsin-Madison, Madison, WI
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - Wei Guo
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI
- Cardiovascular Research Center, University of Wisconsin-Madison, Madison, WI
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4
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Moursy A, Cléry A, Gerhardy S, Betz KM, Rao S, Mazur J, Campagne S, Beusch I, Duszczyk MM, Robinson MD, Panse VG, Allain FHT. RNA recognition by Npl3p reveals U2 snRNA-binding compatible with a chaperone role during splicing. Nat Commun 2023; 14:7166. [PMID: 37935663 PMCID: PMC10630445 DOI: 10.1038/s41467-023-42962-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/27/2023] [Indexed: 11/09/2023] Open
Abstract
The conserved SR-like protein Npl3 promotes splicing of diverse pre-mRNAs. However, the RNA sequence(s) recognized by the RNA Recognition Motifs (RRM1 & RRM2) of Npl3 during the splicing reaction remain elusive. Here, we developed a split-iCRAC approach in yeast to uncover the consensus sequence bound to each RRM. High-resolution NMR structures show that RRM2 recognizes a 5´-GNGG-3´ motif leading to an unusual mille-feuille topology. These structures also reveal how RRM1 preferentially interacts with a CC-dinucleotide upstream of this motif, and how the inter-RRM linker and the region C-terminal to RRM2 contribute to cooperative RNA-binding. Structure-guided functional studies show that Npl3 genetically interacts with U2 snRNP specific factors and we provide evidence that Npl3 melts U2 snRNA stem-loop I, a prerequisite for U2/U6 duplex formation within the catalytic center of the Bact spliceosomal complex. Thus, our findings suggest an unanticipated RNA chaperoning role for Npl3 during spliceosome active site formation.
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Affiliation(s)
- Ahmed Moursy
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Antoine Cléry
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland.
| | - Stefan Gerhardy
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
- Sardona Therapeutics, San Francisco, CA, USA
| | - Katharina M Betz
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Sanjana Rao
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Jarosław Mazur
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Sébastien Campagne
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland
- ARNA laboratory, INSERM U1212, University of Bordeaux, Bordeaux, France
| | - Irene Beusch
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | | | - Mark D Robinson
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Vikram Govind Panse
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
- Faculty of Science, University of Zurich, Zurich, Switzerland.
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5
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De Silva NIU, Lehman N, Fargason T, Paul T, Zhang Z, Zhang J. Unearthing SRSF1's Novel Function in Binding and Unfolding of RNA G-Quadruplexes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.30.563137. [PMID: 37961538 PMCID: PMC10634998 DOI: 10.1101/2023.10.30.563137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
SRSF1 governs splicing of over 1,500 mRNA transcripts. SRSF1 contains two RNA-recognition motifs (RRMs) and a C-terminal Arg/Ser-rich region (RS). It has been thought that SRSF1 RRMs exclusively recognize single-stranded exonic splicing enhancers, while RS lacks RNA-binding specificity. With our success in solving the insolubility problem of SRSF1, we can explore the unknown RNA-binding landscape of SRSF1. We find that SRSF1 RS prefers purine over pyrimidine. Moreover, SRSF1 binds to the G-quadruplex (GQ) from the ARPC2 mRNA, with both RRMs and RS being crucial. Our binding assays show that the traditional RNA-binding sites on the RRM tandem and the Arg in RS are responsible for GQ binding. Interestingly, our FRET and circular dichroism data reveal that SRSF1 unfolds the ARPC2 GQ, with RS leading unfolding and RRMs aiding. Our saturation transfer difference NMR results discover that Arg residues in SRSF1 RS interact with the guanine base but other nucleobases, underscoring the uniqueness of the Arg/guanine interaction. Our luciferase assays confirm that SRSF1 can alleviate the inhibitory effect of GQ on gene expression in the cell. Given the prevalence of RNA GQ and SR proteins, our findings unveil unexplored SR protein functions with broad implications in RNA splicing and translation.
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Affiliation(s)
- Naiduwadura Ivon Upekala De Silva
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL, 35294-1240, USA
| | - Nathan Lehman
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL, 35294-1240, USA
| | - Talia Fargason
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL, 35294-1240, USA
| | - Trenton Paul
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL, 35294-1240, USA
| | - Zihan Zhang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL, 35294-1240, USA
| | - Jun Zhang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, AL, 35294-1240, USA
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6
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Jiang T, Wang L, Tang L, Zeb A, Hou Y. Identification of two short peptide motifs from serine/arginine-rich protein ribonucleic acid recognition motif-1 domain acting as splicing regulators. PeerJ 2023; 11:e16103. [PMID: 37744237 PMCID: PMC10512959 DOI: 10.7717/peerj.16103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/25/2023] [Indexed: 09/26/2023] Open
Abstract
Background Serine/arginine-rich (SR) proteins regulate pre-mRNA splicing. However, structurally similar proteins often behave differently in splicing regulation and the underlying mechanisms are largely unknown. Here, using SMN1/2 minigenes we extensively analyzed four SR proteins, SRSF1/5/6/9. Methods In this study, the effects of these proteins on SMN1/2 exon 7 splicing when tethered at either intron 6 or 7 were evaluated using an MS2-tethering assay. Deletion analysis in four SR proteins and co-overexpression analysis were performed. Results Splicing outcomes varied among all four SR proteins, SRSF1 and SRSF5 function the same at the two sites, acting as repressor and stimulator, respectively; while SRSF6 and SRSF9 promote exon 7 inclusion at only one site. Further, the key domains of each SR proteins were investigated, which identified a potent inhibitory nonapeptide in the C-terminus of SRSF1/9 ribonucleic acid recognition motif-1 (RRM1) and a potent stimulatory heptapeptide at the N-terminus of SRSF5/6 RRM1. Conclusion The insight of the four SR proteins and their domains in affecting SMN gene splicing brings a new perspective on the modes of action of SR proteins; and the functional peptides obtained here offers new ideas for developing splice switching-related therapies.
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Affiliation(s)
- Tao Jiang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
- Department of Rehabilitation, Southwest Hospital, Third Military Medical University Army Medical University, Chongqing, China
| | - Li Wang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
| | - Liang Tang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
| | - Azhar Zeb
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
| | - Yanjun Hou
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
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7
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Cooperative Binding of SRSF3 to Structured 3'ss-α Exon RNA during α Exon Inclusion in the ZO-1 mRNA. Curr Issues Mol Biol 2023; 45:593-603. [PMID: 36661525 PMCID: PMC9857539 DOI: 10.3390/cimb45010039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/28/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
ZO-1α+ and ZO-1α- proteins are expressed in hermetic and leaky tight junctions, respectively. Two cis-acting distant exonic elements partly activate the 240 nucleotide-long α exon producing the ZO-1α+ isoform. However, the elements within and around the α exon and their respective factors involved in its splicing are unknown. To study the dynamic interaction between SRSF3 and its bioinformatically predicted target sites around the 3'ss upstream of the α exon during its activation, we performed EMSA, crosslinking, and in vivo splicing assays by ZO-1 minigene expression and siRNA-mediated silencing in transfected cells. Using V1 RNase, we probed the possible formation of a hairpin RNA structure between the intronic and proximal exonic SRSF3 binding sites. The hairpin sufficed for complex formations in the EMSA. The interaction of SRSF3 with the intronic site promoted the cooperative binding of SRSF3 to the exonic site. Finally, SRSF3 restored α exon activation in SRSF3 knockdown transfectants. Altogether, our results show that SRSF3-hairpin RNA interaction is crucial in the early recognition of 3'ss for α exon activation. It remains to be explored whether SRSF3 recruits or stabilizes the binding of other factors or brings separate splice sites into proximity.
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8
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Hussain SS, Abbas M, Abbas S, Wei M, El-Sappah AH, Sun Y, Li Y, Ragauskas AJ, Li Q. Alternative splicing: transcriptional regulatory network in agroforestry. FRONTIERS IN PLANT SCIENCE 2023; 14:1158965. [PMID: 37123829 PMCID: PMC10132464 DOI: 10.3389/fpls.2023.1158965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 03/13/2023] [Indexed: 05/03/2023]
Abstract
Alternative splicing (AS) in plants plays a key role in regulating the expression of numerous transcripts from a single gene in a regulatory pathway. Variable concentrations of growth regulatory hormones and external stimuli trigger alternative splicing to switch among different growth stages and adapt to environmental stresses. In the AS phenomenon, a spliceosome causes differential transcriptional modifications in messenger RNA (mRNAs), resulting in partial or complete retention of one or more introns as compared to fully spliced mRNA. Differentially expressed proteins translated from intron-retaining messenger RNA (mRNAir) perform vital functions in the feedback mechanism. At the post-transcriptional level, AS causes the remodeling of transcription factors (TFs) by the addition or deletion of binding domains to activate and/or repress transcription. In this study, we have summarized the specific role of AS in the regulation of gene expression through repression and activation of the transcriptional regulatory network under external stimuli and switch among developmental stages.
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Affiliation(s)
- Syed Sarfaraz Hussain
- State Key Laboratory of Tree Genetics and Breeding, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, China
| | - Manzar Abbas
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, Sichuan, China
| | - Sammar Abbas
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Mingke Wei
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, China
| | - Ahmed H. El-Sappah
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, Sichuan, China
- Genetics Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
| | - Yuhan Sun
- State Key Laboratory of Tree Genetics and Breeding, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
| | - Yun Li
- State Key Laboratory of Tree Genetics and Breeding, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
- *Correspondence: Yun Li, ; Arthur J. Ragauskas, ; Quanzi Li,
| | - Arthur J. Ragauskas
- Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
- Joint Institute for Biological Science, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Department of Chemical and Biomolecular Engineering, The University of Tennessee-Knoxville, Knoxville, TN, United States
- *Correspondence: Yun Li, ; Arthur J. Ragauskas, ; Quanzi Li,
| | - Quanzi Li
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, China
- *Correspondence: Yun Li, ; Arthur J. Ragauskas, ; Quanzi Li,
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9
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Saha K, Ghosh G. Cooperative engagement and subsequent selective displacement of SR proteins define the pre-mRNA 3D structural scaffold for early spliceosome assembly. Nucleic Acids Res 2022; 50:8262-8278. [PMID: 35871302 PMCID: PMC9371905 DOI: 10.1093/nar/gkac636] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/04/2022] [Accepted: 07/13/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
We recently reported that serine–arginine-rich (SR) protein-mediated pre-mRNA structural remodeling generates a pre-mRNA 3D structural scaffold that is stably recognized by the early spliceosomal components. However, the intermediate steps between the free pre-mRNA and the assembled early spliceosome are not yet characterized. By probing the early spliceosomal complexes in vitro and RNA-protein interactions in vivo, we show that the SR proteins bind the pre-mRNAs cooperatively generating a substrate that recruits U1 snRNP and U2AF65 in a splice signal-independent manner. Excess U1 snRNP selectively displaces some of the SR protein molecules from the pre-mRNA generating the substrate for splice signal-specific, sequential recognition by U1 snRNP, U2AF65 and U2AF35. Our work thus identifies a novel function of U1 snRNP in mammalian splicing substrate definition, explains the need for excess U1 snRNP compared to other U snRNPs in vivo, demonstrates how excess SR proteins could inhibit splicing, and provides a conceptual basis to examine if this mechanism of splicing substrate definition is employed by other splicing regulatory proteins.
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Affiliation(s)
- Kaushik Saha
- Department of Chemistry and Biochemistry, University of California San Diego , 9500 Gilman Drive , La Jolla , CA 92093-0375, USA
| | - Gourisankar Ghosh
- Department of Chemistry and Biochemistry, University of California San Diego , 9500 Gilman Drive , La Jolla , CA 92093-0375, USA
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10
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Liu Z, Sui A, Wang S, Cui L, Xin Q, Zhang R, Han Y, Shao L, Zhao X. Double synonymous mutations in exon 9 of the Cullin3 gene restore exon inclusion by abolishing hnRNPs inhibition. Hum Mol Genet 2022; 31:4006-4018. [PMID: 35796549 DOI: 10.1093/hmg/ddac148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 06/06/2022] [Accepted: 06/29/2022] [Indexed: 11/13/2022] Open
Abstract
All mutations in exon 9 of the Cullin3 gene associated with pseudohypoaldosteronism type II (PHA II) contribute to exon skipping to different degrees, but the specific molecular mechanism of this aberrant splicing is still unclear. The aims of this study were to investigate the regulatory mechanism underlying two synonymous splicing events, c.1221A > G (p. Glu407Glu) and c.1236G > A (p. Leu412Leu), and to discover a therapeutic strategy for correcting this aberrant splicing by targeting potential regulatory sites. Through a series of RNA pulldown, silver staining, western blotting, siRNA knockdown, in vitro overexpression and single or double site-directed mutagenesis experiments, we first explored the pathogenesis of exon 9 skipping caused by mutations in the CUL3 gene and verified that the main splicing regulators associated with the synonymous c.1221A > G and c.1236G > A mutations were heterogeneous nuclear ribonucleoproteins (hnRNPs). In addition, we verified that introducing another synonymous mutation, c.1224A > G (A18G), significantly rescued the abnormal splicing caused by c.1221A > G and c.1236G > A, highlighting the therapeutic potential for the treatment of PHA II.
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Affiliation(s)
- Zhiying Liu
- Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, 266555, China.,Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, 266071, China
| | - Aihua Sui
- Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, 266555, China
| | - Sai Wang
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, 266071, China.,Department of Dermatology, Peking University First Hospital, Beijing, 100034, China
| | - Li Cui
- Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, 266555, China
| | - Qing Xin
- Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, 266555, China.,Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, 266071, China
| | - Ruixiao Zhang
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, 266071, China
| | - Yue Han
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, 266071, China
| | - Leping Shao
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, 266071, China
| | - Xiangzhong Zhao
- Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, 266555, China
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11
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Jobbins AM, Campagne S, Weinmeister R, Lucas CM, Gosliga AR, Clery A, Chen L, Eperon LP, Hodson MJ, Hudson AJ, Allain FHT, Eperon IC. Exon-independent recruitment of SRSF1 is mediated by U1 snRNP stem-loop 3. EMBO J 2022; 41:e107640. [PMID: 34779515 PMCID: PMC8724738 DOI: 10.15252/embj.2021107640] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 10/04/2021] [Accepted: 10/07/2021] [Indexed: 12/11/2022] Open
Abstract
SRSF1 protein and U1 snRNPs are closely connected splicing factors. They both stimulate exon inclusion, SRSF1 by binding to exonic splicing enhancer sequences (ESEs) and U1 snRNPs by binding to the downstream 5' splice site (SS), and both factors affect 5' SS selection. The binding of U1 snRNPs initiates spliceosome assembly, but SR proteins such as SRSF1 can in some cases substitute for it. The mechanistic basis of this relationship is poorly understood. We show here by single-molecule methods that a single molecule of SRSF1 can be recruited by a U1 snRNP. This reaction is independent of exon sequences and separate from the U1-independent process of binding to an ESE. Structural analysis and cross-linking data show that SRSF1 contacts U1 snRNA stem-loop 3, which is required for splicing. We suggest that the recruitment of SRSF1 to a U1 snRNP at a 5'SS is the basis for exon definition by U1 snRNP and might be one of the principal functions of U1 snRNPs in the core reactions of splicing in mammals.
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Affiliation(s)
- Andrew M Jobbins
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
MRC London Institute of Medical SciencesLondonUK
- Present address:
Institute of Clinical SciencesImperial College LondonLondonUK
| | - Sébastien Campagne
- Institute of BiochemistryETH ZürichSwitzerland
- Present address:
Inserm U1212CNRS UMR5320ARNA LaboratoryBordeaux CedexFrance
| | - Robert Weinmeister
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | - Christian M Lucas
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Alison R Gosliga
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
Institut für Industrielle GenetikAbt.(eilung) SystembiologieUniversität StuttgartStuttgartGermany
| | | | - Li Chen
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Lucy P Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Mark J Hodson
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Andrew J Hudson
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | | | - Ian C Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
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12
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Laliotis GI, Chavdoula E, Paraskevopoulou MD, Kaba A, La Ferlita A, Singh S, Anastas V, Nair KA, Orlacchio A, Taraslia V, Vlachos I, Capece M, Hatzigeorgiou A, Palmieri D, Tsatsanis C, Alaimo S, Sehgal L, Carbone DP, Coppola V, Tsichlis PN. AKT3-mediated IWS1 phosphorylation promotes the proliferation of EGFR-mutant lung adenocarcinomas through cell cycle-regulated U2AF2 RNA splicing. Nat Commun 2021; 12:4624. [PMID: 34330897 PMCID: PMC8324843 DOI: 10.1038/s41467-021-24795-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 03/05/2021] [Indexed: 02/06/2023] Open
Abstract
AKT-phosphorylated IWS1 regulates alternative RNA splicing via a pathway that is active in lung cancer. RNA-seq studies in lung adenocarcinoma cells lacking phosphorylated IWS1, identified a exon 2-deficient U2AF2 splice variant. Here, we show that exon 2 inclusion in the U2AF2 mRNA is a cell cycle-dependent process that is regulated by LEDGF/SRSF1 splicing complexes, whose assembly is controlled by the IWS1 phosphorylation-dependent deposition of histone H3K36me3 marks in the body of target genes. The exon 2-deficient U2AF2 mRNA encodes a Serine-Arginine-Rich (RS) domain-deficient U2AF65, which is defective in CDCA5 pre-mRNA processing. This results in downregulation of the CDCA5-encoded protein Sororin, a phosphorylation target and regulator of ERK, G2/M arrest and impaired cell proliferation and tumor growth. Analysis of human lung adenocarcinomas, confirmed activation of the pathway in EGFR-mutant tumors and showed that pathway activity correlates with tumor stage, histologic grade, metastasis, relapse after treatment, and poor prognosis.
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Affiliation(s)
- Georgios I Laliotis
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA.
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA.
- School of Medicine, University of Crete, Heraklion, Crete, Greece.
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, MD, USA.
| | - Evangelia Chavdoula
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
| | | | - Abdul Kaba
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
| | - Alessandro La Ferlita
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
- Department of Clinical and Experimental Medicine, Bioinformatics Unit, University of Catania, Catania, Italy
| | - Satishkumar Singh
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
- Department of Medicine, Division of Hematology, The Ohio State University, Columbus, OH, USA
| | - Vollter Anastas
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
- Tufts Graduate School of Biomedical Sciences, Program in Genetics, Boston, MA, USA
| | - Keith A Nair
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
| | - Arturo Orlacchio
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
| | - Vasiliki Taraslia
- Molecular Oncology Research Institute, Tufts Medical Center, Boston, MA, USA
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Ioannis Vlachos
- DIANA-Lab, Hellenic Pasteur Institute, Athens, Greece
- Department Of Pathology, Beth Israel-Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Marina Capece
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
| | | | - Dario Palmieri
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
| | - Christos Tsatsanis
- School of Medicine, University of Crete, Heraklion, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
| | - Salvatore Alaimo
- Department of Clinical and Experimental Medicine, Bioinformatics Unit, University of Catania, Catania, Italy
| | - Lalit Sehgal
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
- Department of Medicine, Division of Hematology, The Ohio State University, Columbus, OH, USA
| | - David P Carbone
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
- Department of Internal Medicine, Division of Medical Oncology, The Ohio State University Medical Center, Columbus, OH, USA
| | - Vincenzo Coppola
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA
| | - Philip N Tsichlis
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA.
- The Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH, USA.
- Tufts Graduate School of Biomedical Sciences, Program in Genetics, Boston, MA, USA.
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13
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McSweeney AM, Young VL, Ward VK. Norovirus VPg Binds RNA through a Conserved N-Terminal K/R Basic Patch. Viruses 2021; 13:v13071282. [PMID: 34209211 PMCID: PMC8310136 DOI: 10.3390/v13071282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/23/2021] [Accepted: 06/26/2021] [Indexed: 11/17/2022] Open
Abstract
The viral protein genome-linked (VPg) of noroviruses is a multi-functional protein that participates in essential roles during the viral replication cycle. Predictive analyses indicate that murine norovirus (MNV) VPg contains a disordered N-terminal region with RNA binding potential. VPg proteins were expressed with an N-terminal spidroin fusion protein in insect cells and the interaction with RNA investigated by electrophoretic mobility shift assays (EMSA) against a series of RNA probes (pentaprobes) representing all possible five nucleotide combinations. MNV VPg and human norovirus (HuNV) VPg proteins were directly bound to RNA in a non-specific manner. To identify amino acids involved in binding to RNA, all basic (K/R) residues in the first 12 amino acids of MNV VPg were mutated to alanine. Removal of the K/R amino acids eliminated RNA binding and is consistent with a K/R basic patch RNA binding motif within the disordered N-terminal region of norovirus VPgs. Finally, we show that mutation of the K/R basic patch required for RNA binding eliminates the ability of MNV VPg to induce a G0/G1 cell cycle arrest.
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14
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Warnasooriya C, Feeney CF, Laird KM, Ermolenko DN, Kielkopf CL. A splice site-sensing conformational switch in U2AF2 is modulated by U2AF1 and its recurrent myelodysplasia-associated mutation. Nucleic Acids Res 2020; 48:5695-5709. [PMID: 32343311 PMCID: PMC7261175 DOI: 10.1093/nar/gkaa293] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 04/09/2020] [Accepted: 04/17/2020] [Indexed: 02/02/2023] Open
Abstract
An essential heterodimer of the U2AF1 and U2AF2 pre-mRNA splicing factors nucleates spliceosome assembly at polypyrimidine (Py) signals preceding the major class of 3′ splice sites. U2AF1 frequently acquires an S34F-encoding mutation among patients with myelodysplastic syndromes (MDS). The influence of the U2AF1 subunit and its S34F mutation on the U2AF2 conformations remains unknown. Here, we employ single molecule Förster resonance energy transfer (FRET) to determine the influence of wild-type or S34F-substituted U2AF1 on the conformational dynamics of U2AF2 and its splice site RNA complexes. In the absence of RNA, the U2AF1 subunit stabilizes a high FRET value, which by structure-guided mutagenesis corresponds to a closed conformation of the tandem U2AF2 RNA recognition motifs (RRMs). When the U2AF heterodimer is bound to a strong, uridine-rich splice site, U2AF2 switches to a lower FRET value characteristic of an open, side-by-side arrangement of the RRMs. Remarkably, the U2AF heterodimer binds weak, uridine-poor Py tracts as a mixture of closed and open U2AF2 conformations, which are modulated by the S34F mutation. Shifts between open and closed U2AF2 may underlie U2AF1-dependent splicing of degenerate Py tracts and contribute to a subset of S34F-dysregulated splicing events in MDS patients.
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Affiliation(s)
- Chandani Warnasooriya
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Callen F Feeney
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Kholiswa M Laird
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Dmitri N Ermolenko
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Clara L Kielkopf
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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15
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Zhang H, Brown RD, Stenmark KR, Hu CJ. RNA-Binding Proteins in Pulmonary Hypertension. Int J Mol Sci 2020; 21:ijms21113757. [PMID: 32466553 PMCID: PMC7312837 DOI: 10.3390/ijms21113757] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/21/2022] Open
Abstract
Pulmonary hypertension (PH) is a life-threatening disease characterized by significant vascular remodeling and aberrant expression of genes involved in inflammation, apoptosis resistance, proliferation, and metabolism. Effective therapeutic strategies are limited, as mechanisms underlying PH pathophysiology, especially abnormal expression of genes, remain unclear. Most PH studies on gene expression have focused on gene transcription. However, post-transcriptional alterations have been shown to play a critical role in inflammation and metabolic changes in diseases such as cancer and systemic cardiovascular diseases. In these diseases, RNA-binding proteins (RBPs) have been recognized as important regulators of aberrant gene expression via post-transcriptional regulation; however, their role in PH is less clear. Identifying RBPs in PH is of great importance to better understand PH pathophysiology and to identify new targets for PH treatment. In this manuscript, we review the current knowledge on the role of dysregulated RBPs in abnormal mRNA gene expression as well as aberrant non-coding RNA processing and expression (e.g., miRNAs) in PH.
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Affiliation(s)
- Hui Zhang
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (H.Z.); (R.D.B.); (K.R.S.)
| | - R. Dale Brown
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (H.Z.); (R.D.B.); (K.R.S.)
| | - Kurt R. Stenmark
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (H.Z.); (R.D.B.); (K.R.S.)
| | - Cheng-Jun Hu
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (H.Z.); (R.D.B.); (K.R.S.)
- Department of Craniofacial Biology School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Correspondence: ; Tel.: +1-303-724-4576; Fax: +1-303-724-4580
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16
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hnRNP A1 Regulates Alternative Splicing of Tau Exon 10 by Targeting 3' Splice Sites. Cells 2020; 9:cells9040936. [PMID: 32290247 PMCID: PMC7226981 DOI: 10.3390/cells9040936] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 12/04/2022] Open
Abstract
The ratio control of 4R-Tau/3R-Tau by alternative splicing of Tau exon 10 is important for maintaining brain functions. In this study, we show that hnRNP A1 knockdown induces inclusion of endogenous Tau exon 10, conversely, overexpression of hnRNP A1 promotes exon 10 skipping of Tau. In addition, hnRNP A1 inhibits splicing of intron 9, but not intron 10. Furthermore, hnRNP A1 directly interacts with the 3′ splice site of exon 10 to regulate its functions in alternative splicing. Finally, gene ontology analysis demonstrates that hnRNP A1-induced splicing and gene expression targets a subset of genes with neuronal function.
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17
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Kundinger SR, Bishof I, Dammer EB, Duong DM, Seyfried NT. Middle-Down Proteomics Reveals Dense Sites of Methylation and Phosphorylation in Arginine-Rich RNA-Binding Proteins. J Proteome Res 2020; 19:1574-1591. [PMID: 31994892 DOI: 10.1021/acs.jproteome.9b00633] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Post-translational modifications (PTMs) within arginine (Arg)-rich RNA-binding proteins, such as phosphorylation and methylation, regulate multiple steps in RNA metabolism. However, the identification of PTMs within Arg-rich domains with complete trypsin digestion is extremely challenging due to the high density of Arg residues within these proteins. Here, we report a middle-down proteomic approach coupled with electron-transfer dissociation (ETD) mass spectrometry to map previously unknown sites of phosphorylation and methylation within the Arg-rich domains of U1-70K and structurally similar RNA-binding proteins from nuclear extracts of human embryonic kidney (HEK)-293T cells. Notably, the Arg-rich domains in RNA-binding proteins are densely modified by methylation and phosphorylation compared with the remainder of the proteome, with methylation and phosphorylation favoring RSRS motifs. Although they favor a common motif, analysis of combinatorial PTMs within RSRS motifs indicates that phosphorylation and methylation do not often co-occur, suggesting that they may functionally oppose one another. Furthermore, we show that phosphorylation may modify interactions between Arg-rich proteins, as serine-arginine splicing factor 2 (SRSF2) has a stronger association with U1-70K and LUC7L3 upon dephosphorylation. Collectively, these findings suggest that the level of PTMs within Arg-rich domains may be among the highest in the proteome and a possible unexplored regulator of RNA-binding protein interactions.
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18
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Jobbins AM, Reichenbach LF, Lucas CM, Hudson AJ, Burley GA, Eperon IC. The mechanisms of a mammalian splicing enhancer. Nucleic Acids Res 2019; 46:2145-2158. [PMID: 29394380 PMCID: PMC5861446 DOI: 10.1093/nar/gky056] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/19/2018] [Indexed: 12/21/2022] Open
Abstract
Exonic splicing enhancer (ESE) sequences are bound by serine & arginine-rich (SR) proteins, which in turn enhance the recruitment of splicing factors. It was inferred from measurements of splicing around twenty years ago that Drosophila doublesex ESEs are bound stably by SR proteins, and that the bound proteins interact directly but with low probability with their targets. However, it has not been possible with conventional methods to demonstrate whether mammalian ESEs behave likewise. Using single molecule multi-colour colocalization methods to study SRSF1-dependent ESEs, we have found that that the proportion of RNA molecules bound by SRSF1 increases with the number of ESE repeats, but only a single molecule of SRSF1 is bound. We conclude that initial interactions between SRSF1 and an ESE are weak and transient, and that these limit the activity of a mammalian ESE. We tested whether the activation step involves the propagation of proteins along the RNA or direct interactions with 3' splice site components by inserting hexaethylene glycol or abasic RNA between the ESE and the target 3' splice site. These insertions did not block activation, and we conclude that the activation step involves direct interactions. These results support a model in which regulatory proteins bind transiently and in dynamic competition, with the result that each ESE in an exon contributes independently to the probability that an activator protein is bound and in close proximity to a splice site.
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Affiliation(s)
- Andrew M Jobbins
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell Biology, University of Leicester, UK
| | | | - Christian M Lucas
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell Biology, University of Leicester, UK
| | - Andrew J Hudson
- Leicester Institute of Structural & Chemical Biology and Department of Chemistry, University of Leicester, UK
| | - Glenn A Burley
- Department of Pure and Applied Chemistry, University of Strathclyde, UK
| | - Ian C Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell Biology, University of Leicester, UK
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19
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Ptok J, Müller L, Theiss S, Schaal H. Context matters: Regulation of splice donor usage. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194391. [PMID: 31202784 DOI: 10.1016/j.bbagrm.2019.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/07/2019] [Accepted: 06/09/2019] [Indexed: 11/16/2022]
Abstract
Elaborate research on splicing, starting in the late seventies, evolved from the discovery that 5' splice sites are recognized by their complementarity to U1 snRNA towards the realization that RNA duplex formation cannot be the sole basis for 5'ss selection. Rather, their recognition is highly influenced by a number of context factors including transcript architecture as well as splicing regulatory elements (SREs) in the splice site neighborhood. In particular, proximal binding of splicing regulatory proteins highly influences splicing outcome. The importance of SRE integrity especially becomes evident in the light of human pathogenic mutations where single nucleotide changes in SREs can severely affect the resulting transcripts. Bioinformatics tools nowadays greatly assist in the computational evaluation of 5'ss, their neighborhood and the impact of pathogenic mutations. Although predictions are already quite robust, computational evaluation of the splicing regulatory landscape still faces challenges to increase future reliability. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Johannes Ptok
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Lisa Müller
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Stephan Theiss
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Heiner Schaal
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany.
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20
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Morton M, AlTamimi N, Butt H, Reddy ASN, Mahfouz M. Serine/Arginine-rich protein family of splicing regulators: New approaches to study splice isoform functions. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 283:127-134. [PMID: 31128682 DOI: 10.1016/j.plantsci.2019.02.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 02/19/2019] [Accepted: 02/23/2019] [Indexed: 05/06/2023]
Abstract
Serine/arginine-rich (SR) proteins are conserved RNA-binding proteins that play major roles in RNA metabolism. They function as molecular adaptors, facilitate spliceosome assembly and modulate constitutive and alternative splicing of pre-mRNAs. Pre-mRNAs encoding SR proteins and many other proteins involved in stress responses are extensively alternatively spliced in response to diverse stresses. Hence, it is proposed that stress-induced changes in splice isoforms contribute to the adaptation of plants to stress responses. However, functions of most SR genes and their splice isoforms in stress responses are not known. Lack of easy and robust tools hindered the progress in this area. Emerging technologies such as CRISPR/Cas9 will facilitate studies of SR function by enabling the generation of single and multiple knock-out mutants of SR subfamily members. Moreover, CRISPR/Cas13 allows targeted manipulation of splice isoforms from SR and other genes in a constitutive or tissue-specific manner to evaluate functions of individual splice variants. Identification of the in vivo targets of SR proteins and their splice variants using the recently developed TRIBE (Targets of RNA-binding proteins Identified By Editing) and other methods will help unravel their mode of action and splicing regulatory elements under various conditions. These new approaches are expected to provide significant new insights into the roles of SRs and splice isoforms in plants adaptation to diverse stresses.
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Affiliation(s)
- Mitchell Morton
- Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Nadia AlTamimi
- Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Haroon Butt
- Laboratory for Genome Engineering, Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Anireddy S N Reddy
- Department of Biology, Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Magdy Mahfouz
- Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Laboratory for Genome Engineering, Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
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21
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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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22
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An Y, Zou Y, Cao Y, Yao M, Ma N, Wu Y, Yang J, Liu H, Zhang B. The nuclear GSK-3β regulated post-transcriptional processing of mRNA through phosphorylation of SC35. Mol Cell Biochem 2018; 451:55-67. [PMID: 30030778 DOI: 10.1007/s11010-018-3393-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 06/26/2018] [Indexed: 01/02/2023]
Abstract
Glycogen synthase kinase-3β (GSK-3β) is a multifunctional serine/threonine kinase and regulates a variety of biological processes. Recent studies show GSK-3β can regulate pre-mRNA processing and transcription through phosphorylation of multiple splicing factors, but the detailed mechanism is still undetermined. In this study, we further proved that GSK-3β could specifically co-localize with SC35 in nuclear speckles depending on its kinase activity. Immunofluorescence and FISH studies showed the activity of nuclear GSK-3β regulated the assembly of nuclear speckles and consequently modulated the post-transcriptional processing of mRNA. In addition, GSK-3β phosphorylated SC35 and promoted its hyperphosphorylation, in which the unique C-terminal sequences were particularly important to efficiently sequential multiple phosphorylation of SC35. Hyperphosphorylated SC35 converged into cluster and lost its ability to perform splicing in nuclear speckles. More importantly, the nuclear GSK-3β activity could be a part of Wnt/β-catenin signaling activation by TCF4 and might take part in embryonic or tumorigenesis of cells.
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Affiliation(s)
- Yu An
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - YongXin Zou
- Eye Hospital, China Academy of Chinese Medical Sciences, Beijing, 100040, China
| | - YaNan Cao
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - MengFei Yao
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - NingNing Ma
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - YaQian Wu
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Jing Yang
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - HaiJing Liu
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Bo Zhang
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
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23
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Van Ruyskensvelde V, Van Breusegem F, Van Der Kelen K. Post-transcriptional regulation of the oxidative stress response in plants. Free Radic Biol Med 2018; 122:181-192. [PMID: 29496616 DOI: 10.1016/j.freeradbiomed.2018.02.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 12/30/2022]
Abstract
Due to their sessile lifestyle, plants can be exposed to several kinds of stresses that will increase the production of reactive oxygen species (ROS), such as hydrogen peroxide, singlet oxygen, and hydroxyl radicals, in the plant cells and activate several signaling pathways that cause alterations in the cellular metabolism. Nevertheless, when ROS production outreaches a certain level, oxidative damage to nucleic acids, lipids, metabolites, and proteins will occur, finally leading to cell death. Until now, the most comprehensive and detailed readout of oxidative stress responses is undoubtedly obtained at the transcriptome level. However, transcript levels often do not correlate with the corresponding protein levels. Indeed, together with transcriptional regulations, post-transcriptional, translational, and/or post-translational regulations will shape the active proteome. Here, we review the current knowledge on the post-transcriptional gene regulation during the oxidative stress responses in planta.
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Affiliation(s)
- Valerie Van Ruyskensvelde
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium.
| | - Katrien Van Der Kelen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium
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24
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Moon H, Cho S, Loh TJ, Jang HN, Liu Y, Choi N, Oh J, Ha J, Zhou J, Cho S, Kim DE, Ye MB, Zheng X, Shen H. SRSF2 directly inhibits intron splicing to suppresses cassette exon inclusion. BMB Rep 2018; 50:423-428. [PMID: 28712387 PMCID: PMC5595172 DOI: 10.5483/bmbrep.2017.50.8.103] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Indexed: 12/30/2022] Open
Abstract
SRSF2, a Serine-Arginine rich (SR) protein, is a splicing activator that mediates exon inclusion and exclusion events equally well. Here we show SRSF2 directly suppresses intron splicing to suppress cassette exon inclusion in SMN pre-mRNA. Through a serial mutagenesis, we demonstrate that a 10 nt RNA sequence surrounding the branch-point (BP), is important for SRSF2-mediated inhibition of cassette exon inclusion through directly interacting with SRSF2. We conclude that SRSF2 inhibits intron splicing to promote exon exclusion.
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Affiliation(s)
- Heegyum Moon
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Sunghee Cho
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Tiing Jen Loh
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Ha Na Jang
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Yongchao Liu
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Namjeong Choi
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Jagyeong Oh
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Jiyeon Ha
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Jianhua Zhou
- JiangSu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226019, China
| | - Sungchan Cho
- Bio-Therapeutics Research Institute, Korea Research Institute of Bioscience and Biotechnology, Chungbuk 28116, Korea
| | - Dong-Eun Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Michael B Ye
- Division of Liberal Arts and Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Xuexiu Zheng
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Haihong Shen
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
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25
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Lee AR, Che N, Lovnicki JM, Dong X. Development of Neuroendocrine Prostate Cancers by the Ser/Arg Repetitive Matrix 4-Mediated RNA Splicing Network. Front Oncol 2018; 8:93. [PMID: 29666783 PMCID: PMC5891588 DOI: 10.3389/fonc.2018.00093] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 03/16/2018] [Indexed: 12/19/2022] Open
Abstract
While the use of next-generation androgen receptor pathway inhibition (ARPI) therapy has significantly increased the survival of patients with metastatic prostate adenocarcinoma (AdPC), several groups have reported a treatment-resistant mechanism, whereby cancer cells can become androgen receptor (AR) indifferent and gain a neuroendocrine (NE)-like phenotype. This subtype of castration-resistant prostate cancer has been termed "treatment-induced castration-resistant neuroendocrine prostate cancer" (CRPC-NE). Recent reports indicate that the overall genomic landscapes of castration-resistant tumors with AdPC phenotypes and CRPC-NE are not significantly altered. However, CRPC-NE tumors have been found to contain a NE-specific pattern throughout their epigenome and splicing transcriptome, which are significantly modified. The molecular mechanisms by which CRPC-NE develops remain unclear, but several factors have been implicated in the progression of the disease. Recently, Ser/Arg repetitive matrix 4 (SRRM4), a neuronal-specific RNA splicing factor that is upregulated in CRPC-NE tumors, has been shown to establish a CRPC-NE-unique splicing transcriptome, to induce a NE-like morphology in AdPC cells, and, most importantly, to transform AdPC cells into CRPC-NE xenografts under ARPI. Moreover, the SRRM4-targeted splicing genes are highly enriched in various neuronal processes, suggesting their roles in facilitating a CRPC-NE program. This article will address the importance of SRRM4-mediated alternative RNA splicing in reprogramming translated proteins to facilitate NE differentiation, survival, and proliferation of cells to establish CRPC-NE tumors. In addition, we will discuss the potential roles of SRRM4 in conjunction with other known pathways and factors important for CRPC-NE development, such as the AR pathway, TP53 and RB1 genes, the FOXA family of proteins, and environmental factors. This study aims to explore the multifaceted functions of SRRM4 and SRRM4-mediated splicing in driving a CRPC-NE program as a coping mechanism for therapy resistance, as well as define future SRRM4-targeted therapeutic approaches for treating CRPC-NE or mitigating its development.
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Affiliation(s)
- Ahn R Lee
- Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Nicole Che
- Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jessica M Lovnicki
- Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Xuesen Dong
- Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada
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26
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Suess B, Kemmerer K, Weigand JE. Splicing and Alternative Splicing Impact on Gene Design. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Beatrix Suess
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
| | - Katrin Kemmerer
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
| | - Julia E. Weigand
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
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27
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Chen L, Weinmeister R, Kralovicova J, Eperon LP, Vorechovsky I, Hudson AJ, Eperon IC. Stoichiometries of U2AF35, U2AF65 and U2 snRNP reveal new early spliceosome assembly pathways. Nucleic Acids Res 2017; 45:2051-2067. [PMID: 27683217 PMCID: PMC5389562 DOI: 10.1093/nar/gkw860] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/16/2016] [Indexed: 12/24/2022] Open
Abstract
The selection of 3΄ splice sites (3΄ss) is an essential early step in mammalian RNA splicing reactions, but the processes involved are unknown. We have used single molecule methods to test whether the major components implicated in selection, the proteins U2AF35 and U2AF65 and the U2 snRNP, are able to recognize alternative candidate sites or are restricted to one pre-specified site. In the presence of adenosine triphosphate (ATP), all three components bind in a 1:1 stoichiometry with a 3΄ss. Pre-mRNA molecules with two alternative 3΄ss can be bound concurrently by two molecules of U2AF or two U2 snRNPs, so none of the components are restricted. However, concurrent occupancy inhibits splicing. Stoichiometric binding requires conditions consistent with coalescence of the 5΄ and 3΄ sites in a complex (I, initial), but if this cannot form the components show unrestricted and stochastic association. In the absence of ATP, when complex E forms, U2 snRNP association is unrestricted. However, if protein dephosphorylation is prevented, an I-like complex forms with stoichiometric association of U2 snRNPs and the U2 snRNA is base-paired to the pre-mRNA. Complex I differs from complex A in that the formation of complex A is associated with the loss of U2AF65 and 35.
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Affiliation(s)
- Li Chen
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
| | - Robert Weinmeister
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
| | - Jana Kralovicova
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Lucy P Eperon
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
| | - Igor Vorechovsky
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Andrew J Hudson
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Chemistry, Leicester LE1 7RH, UK
| | - Ian C Eperon
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
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28
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Ohno K, Takeda JI, Masuda A. Rules and tools to predict the splicing effects of exonic and intronic mutations. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 9. [DOI: 10.1002/wrna.1451] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer; Nagoya University Graduate School of Medicine; Nagoya Japan
| | - Jun-ichi Takeda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer; Nagoya University Graduate School of Medicine; Nagoya Japan
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer; Nagoya University Graduate School of Medicine; Nagoya Japan
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29
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Liu Y, Nie H, Liu C, Zhai X, Sang Q, Wang Y, Shi D, Wang L, Xu Z. Angulin proteins ILDR1 and ILDR2 regulate alternative pre-mRNA splicing through binding to splicing factors TRA2A, TRA2B, or SRSF1. Sci Rep 2017; 7:7466. [PMID: 28785060 PMCID: PMC5547134 DOI: 10.1038/s41598-017-07530-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 06/29/2017] [Indexed: 01/08/2023] Open
Abstract
Angulin proteins are a group of evolutionally conserved type I transmembrane proteins that contain an extracellular Ig-like domain. In mammals, three angulin proteins have been identified, namely immunoglobulin-like domain containing receptor 1 (ILDR1), immunoglobulin-like domain containing receptor 2 (ILDR2), and lipolysis-stimulated lipoprotein receptor (LSR). All three proteins have been shown to localize at tight junctions (TJs) and are important for TJ formation. Mutations in ILDR1 gene have been shown to cause non-syndromic hearing loss (NSHL). In the present work, we show that ILDR1 binds to splicing factors TRA2A, TRA2B, and SRSF1, and translocates into the nuclei when the splicing factors are present. Moreover, ILDR1 affects alternative splicing of Tubulin delta 1 (TUBD1), IQ motif containing B1 (IQCB1), and Protocadherin 19 (Pcdh19). Further investigation show that ILDR2, but not LSR, also binds to the splicing factors and regulates alternative splicing. When endogenous ILDR1 and ILDR2 expression is knockdown with siRNAs in cultured cells, alternative splicing of TUBD1 and IQCB1 is affected. In conclusion, we show here that angulin proteins ILDR1 and ILDR2 are involved in alternative pre-mRNA splicing via binding to splicing factors TRA2A, TRA2B, or SRSF1.
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Affiliation(s)
- Yueyue Liu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, Shandong, 250100, China
| | - Hongyun Nie
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, Shandong, 250100, China
| | - Chengcheng Liu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, Shandong, 250100, China
| | - Xiaoyan Zhai
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, Shandong, 250100, China
| | - Qing Sang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, 200032, China
| | - Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, Shandong, 250100, China
| | - Deli Shi
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, Shandong, 250100, China.,Laboratoire de Biologie du Développement, Institut de Biologie Paris-Seine, Sorbonne Universités, Paris, France
| | - Lei Wang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, 200032, China.
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University School of Life Sciences, Jinan, Shandong, 250100, China.
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30
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Jenkins JL, Kielkopf CL. Splicing Factor Mutations in Myelodysplasias: Insights from Spliceosome Structures. Trends Genet 2017; 33:336-348. [PMID: 28372848 PMCID: PMC5447463 DOI: 10.1016/j.tig.2017.03.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 01/08/2023]
Abstract
Somatic mutations of pre-mRNA splicing factors recur among patients with myelodysplastic syndrome (MDS) and related malignancies. Although these MDS-relevant mutations alter the splicing of a subset of transcripts, the mechanisms by which these single amino acid substitutions change gene expression remain controversial. New structures of spliceosome intermediates and associated protein complexes shed light on the molecular interactions mediated by 'hotspots' of the SF3B1 and U2AF1 pre-mRNA splicing factors. The frequently mutated SF3B1 residues contact the pre-mRNA splice site. Based on structural homology with other spliceosome subunits, and recent findings of altered RNA binding by mutant U2AF1 proteins, we suggest that affected U2AF1 residues also contact pre-mRNA. Altered pre-mRNA recognition emerges as a molecular theme among MDS-relevant mutations of pre-mRNA splicing factors.
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Affiliation(s)
- Jermaine L Jenkins
- Center for RNA Biology and Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Clara L Kielkopf
- Center for RNA Biology and Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
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31
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Hillebrand F, Peter JO, Brillen AL, Otte M, Schaal H, Erkelenz S. Differential hnRNP D isoform incorporation may confer plasticity to the ESSV-mediated repressive state across HIV-1 exon 3. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:205-217. [PMID: 27919832 DOI: 10.1016/j.bbagrm.2016.12.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/22/2016] [Accepted: 12/01/2016] [Indexed: 11/27/2022]
Abstract
Even though splicing repression by hnRNP complexes bound to exonic sequences is well-documented, the responsible effector domains of hnRNP proteins have been described for only a select number of hnRNP constituents. Thus, there is only limited information available for possible varying silencer activities amongst different hnRNP proteins and composition changes within possible hnRNP complex assemblies. In this study, we identified the glycine-rich domain (GRD) of hnRNP proteins as a unifying feature in splice site repression. We also show that all four hnRNP D isoforms can act as genuine splicing repressors when bound to exonic positions. The presence of an extended GRD, however, seemed to potentiate the hnRNP D silencer activity of isoforms p42 and p45. Moreover, we demonstrate that hnRNP D proteins associate with the HIV-1 ESSV silencer complex, probably through direct recognition of "UUAG" sequences overlapping with the previously described "UAGG" motifs bound by hnRNP A1. Consequently, this spatial proximity seems to cause mutual interference between hnRNP A1 and hnRNP D. This interplay between hnRNP A1 and D facilitates a dynamic regulation of the repressive state of HIV-1 exon 3 which manifests as fluctuating relative levels of spliced vpr- and unspliced gag/pol-mRNAs.
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Affiliation(s)
- Frank Hillebrand
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Jan Otto Peter
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Anna-Lena Brillen
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Marianne Otte
- Institute of Evolutionary Genetics, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Heiner Schaal
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Steffen Erkelenz
- Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany; Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
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32
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Chen CK, Blanco M, Jackson C, Aznauryan E, Ollikainen N, Surka C, Chow A, Cerase A, McDonel P, Guttman M. Xist recruits the X chromosome to the nuclear lamina to enable chromosome-wide silencing. Science 2016; 354:468-472. [PMID: 27492478 DOI: 10.1126/science.aae0047] [Citation(s) in RCA: 185] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 07/25/2016] [Indexed: 12/12/2022]
Abstract
The Xist long noncoding RNA orchestrates X chromosome inactivation, a process that entails chromosome-wide silencing and remodeling of the three-dimensional (3D) structure of the X chromosome. Yet, it remains unclear whether these changes in nuclear structure are mediated by Xist and whether they are required for silencing. Here, we show that Xist directly interacts with the Lamin B receptor, an integral component of the nuclear lamina, and that this interaction is required for Xist-mediated silencing by recruiting the inactive X to the nuclear lamina and by doing so enables Xist to spread to actively transcribed genes across the X. Our results demonstrate that lamina recruitment changes the 3D structure of DNA, enabling Xist and its silencing proteins to spread across the X to silence transcription.
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Affiliation(s)
- Chun-Kan Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mario Blanco
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Constanza Jackson
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Erik Aznauryan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Noah Ollikainen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Christine Surka
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Amy Chow
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Andrea Cerase
- European Molecular Biology Laboratory-Monterotondo, Via Ramarini 32, 00015 Monterotondo (RM), Italy
| | - Patrick McDonel
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Mitchell Guttman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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33
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Järvelin AI, Noerenberg M, Davis I, Castello A. The new (dis)order in RNA regulation. Cell Commun Signal 2016; 14:9. [PMID: 27048167 PMCID: PMC4822317 DOI: 10.1186/s12964-016-0132-3] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/21/2016] [Indexed: 02/03/2023] Open
Abstract
RNA-binding proteins play a key role in the regulation of all aspects of RNA metabolism, from the synthesis of RNA to its decay. Protein-RNA interactions have been thought to be mostly mediated by canonical RNA-binding domains that form stable secondary and tertiary structures. However, a number of pioneering studies over the past decades, together with recent proteome-wide data, have challenged this view, revealing surprising roles for intrinsically disordered protein regions in RNA binding. Here, we discuss how disordered protein regions can mediate protein-RNA interactions, conceptually grouping these regions into RS-rich, RG-rich, and other basic sequences, that can mediate both specific and non-specific interactions with RNA. Disordered regions can also influence RNA metabolism through protein aggregation and hydrogel formation. Importantly, protein-RNA interactions mediated by disordered regions can influence nearly all aspects of co- and post-transcriptional RNA processes and, consequently, their disruption can cause disease. Despite growing interest in disordered protein regions and their roles in RNA biology, their mechanisms of binding, regulation, and physiological consequences remain poorly understood. In the coming years, the study of these unorthodox interactions will yield important insights into RNA regulation in cellular homeostasis and disease.
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Affiliation(s)
- Aino I. Järvelin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Marko Noerenberg
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Alfredo Castello
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
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34
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Experimental approaches to studying the nature and impact of splicing variation in zebrafish. Methods Cell Biol 2016; 135:259-88. [PMID: 27443930 DOI: 10.1016/bs.mcb.2016.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
From a fixed number of genes carried in all cells, organisms create considerable diversity in cellular phenotype through differential regulation of gene expression. One prevalent source of transcriptome diversity is alternative pre-mRNA splicing, which is manifested in many different forms. Zebrafish models of splicing dysfunction due to mutated spliceosome components provide opportunity to link biochemical analyses of spliceosome structure and function with whole organism phenotypic outcomes. Drawing from experience with two zebrafish mutants: cephalophŏnus (a prpf8 mutant, isolated for defects in granulopoiesis) and caliban (a rnpc3 mutant, isolated for defects in digestive organ development), we describe the use of glycerol gradient sedimentation and native gel electrophoresis to resolve components of aberrant splicing complexes. We also describe how RNAseq can be employed to examine relatively rare alternative splicing events including intron retention. Such experimental approaches in zebrafish can promote understanding of how splicing variation and dysfunction contribute to phenotypic diversity and disease pathogenesis.
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35
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An extended U2AF(65)-RNA-binding domain recognizes the 3' splice site signal. Nat Commun 2016; 7:10950. [PMID: 26952537 PMCID: PMC4786784 DOI: 10.1038/ncomms10950] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 02/03/2016] [Indexed: 12/12/2022] Open
Abstract
How the essential pre-mRNA splicing factor U2AF65 recognizes the polypyrimidine (Py) signals of the major class of 3′ splice sites in human gene transcripts remains incompletely understood. We determined four structures of an extended U2AF65–RNA-binding domain bound to Py-tract oligonucleotides at resolutions between 2.0 and 1.5 Å. These structures together with RNA binding and splicing assays reveal unforeseen roles for U2AF65 inter-domain residues in recognizing a contiguous, nine-nucleotide Py tract. The U2AF65 linker residues between the dual RNA recognition motifs (RRMs) recognize the central nucleotide, whereas the N- and C-terminal RRM extensions recognize the 3′ terminus and third nucleotide. Single-molecule FRET experiments suggest that conformational selection and induced fit of the U2AF65 RRMs are complementary mechanisms for Py-tract association. Altogether, these results advance the mechanistic understanding of molecular recognition for a major class of splice site signals. The pre-mRNA splicing factor U2AF65 recognizes 3′ splice sites in human gene transcripts, but the details are not fully understood. Here, the authors report U2AF65 structures and single molecule FRET that reveal mechanistic insights into splice site recognition.
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Quesnel-Vallières M, Irimia M, Cordes SP, Blencowe BJ. Essential roles for the splicing regulator nSR100/SRRM4 during nervous system development. Genes Dev 2015; 29:746-59. [PMID: 25838543 PMCID: PMC4387716 DOI: 10.1101/gad.256115.114] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Quesnel-Vallières et al. show that loss of the vertebrate- and neural-specific Ser/Arg repeat-related protein of 100 kDa (nSR100/SRRM4) impairs development of the central and peripheral nervous systems. Accompanying these developmental defects are widespread changes in alternative splicing (AS) that primarily result in shifts to nonneural patterns for different classes of splicing events. The main component of the altered AS program comprises 3- to 27-nt neural microexons, and inclusion of a 6-nt nSR100-activated microexon in Unc13b transcripts is sufficient to rescue a neuritogenesis defect in nSR100 mutant primary neurons. Alternative splicing (AS) generates vast transcriptomic complexity in the vertebrate nervous system. However, the extent to which trans-acting splicing regulators and their target AS regulatory networks contribute to nervous system development is not well understood. To address these questions, we generated mice lacking the vertebrate- and neural-specific Ser/Arg repeat-related protein of 100 kDa (nSR100/SRRM4). Loss of nSR100 impairs development of the central and peripheral nervous systems in part by disrupting neurite outgrowth, cortical layering in the forebrain, and axon guidance in the corpus callosum. Accompanying these developmental defects are widespread changes in AS that primarily result in shifts to nonneural patterns for different classes of splicing events. The main component of the altered AS program comprises 3- to 27-nucleotide (nt) neural microexons, an emerging class of highly conserved AS events associated with the regulation of protein interaction networks in developing neurons and neurological disorders. Remarkably, inclusion of a 6-nt, nSR100-activated microexon in Unc13b transcripts is sufficient to rescue a neuritogenesis defect in nSR100 mutant primary neurons. These results thus reveal critical in vivo neurodevelopmental functions of nSR100 and further link these functions to a conserved program of neuronal microexon splicing.
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Affiliation(s)
- Mathieu Quesnel-Vallières
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Manuel Irimia
- Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Sabine P Cordes
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Benjamin J Blencowe
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada;
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Structure-guided U2AF65 variant improves recognition and splicing of a defective pre-mRNA. Proc Natl Acad Sci U S A 2014; 111:17420-5. [PMID: 25422459 DOI: 10.1073/pnas.1412743111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purine interruptions of polypyrimidine (Py) tract splice site signals contribute to human genetic diseases. The essential splicing factor U2AF(65) normally recognizes a Py tract consensus sequence preceding the major class of 3' splice sites. We found that neurofibromatosis- or retinitis pigmentosa-causing mutations in the 5' regions of Py tracts severely reduce U2AF(65) affinity. Conversely, we identified a preferred binding site of U2AF(65) for purine substitutions in the 3' regions of Py tracts. Based on a comparison of new U2AF(65) structures bound to either A- or G-containing Py tracts with previously identified pyrimidine-containing structures, we expected to find that a D231V amino acid change in U2AF(65) would specify U over other nucleotides. We found that the crystal structure of the U2AF(65)-D231V variant confirms favorable packing between the engineered valine and a target uracil base. The D231V amino acid change restores U2AF(65) affinity for two mutated splice sites that cause human genetic diseases and successfully promotes splicing of a defective retinitis pigmentosa-causing transcript. We conclude that reduced U2AF(65) binding is a molecular consequence of disease-relevant mutations, and that a structure-guided U2AF(65) variant is capable of manipulating gene expression in eukaryotic cells.
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38
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Howard JM, Sanford JR. The RNAissance family: SR proteins as multifaceted regulators of gene expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:93-110. [PMID: 25155147 DOI: 10.1002/wrna.1260] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/09/2014] [Accepted: 07/14/2014] [Indexed: 12/29/2022]
Abstract
Serine and arginine-rich (SR) proteins play multiple roles in the eukaryotic gene expression pathway. Initially described as constitutive and alternative splicing factors, now it is clear that SR proteins are key determinants of exon identity and function as molecular adaptors, linking the pre-messenger RNA (pre-mRNA) to the splicing machinery. In addition, now SR proteins are implicated in many aspects of mRNA and noncoding RNA (ncRNA) processing well beyond splicing. These unexpected roles, including RNA transcription, export, translation, and decay, may prove to be the rule rather than the exception. To simply define, this family of RNA-binding proteins as splicing factors belies the broader roles of SR proteins in post-transcriptional gene expression.
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Affiliation(s)
- Jonathan M Howard
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, USA
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Maslon MM, Heras SR, Bellora N, Eyras E, Cáceres JF. The translational landscape of the splicing factor SRSF1 and its role in mitosis. eLife 2014; 3:e02028. [PMID: 24842991 PMCID: PMC4027812 DOI: 10.7554/elife.02028] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 04/21/2014] [Indexed: 12/19/2022] Open
Abstract
The shuttling Serine/Arginine rich (SR) protein SRSF1 (previously known as SF2/ASF) is a splicing regulator that also activates translation in the cytoplasm. In order to dissect the gene network that is translationally regulated by SRSF1, we performed a high-throughput deep sequencing analysis of polysomal fractions in cells overexpressing SRSF1. We identified approximately 1,500 mRNAs that are translational targets of SRSF1. These include mRNAs encoding proteins involved in cell cycle regulation, such as spindle, kinetochore and M phase proteins, which are essential for accurate chromosome segregation. Indeed, we show that translational activity of SRSF1 is required for normal mitotic progression. Furthermore, we found that mRNAs that display alternative splicing changes upon SRSF1 overexpression are also its translational targets; strongly suggesting that SRSF1 couples pre-mRNA splicing and translation. These data provide insights on the complex role of SRSF1 in the control of gene expression at multiple levels and its implications in cancer.
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Affiliation(s)
- Magdalena M Maslon
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Sara R Heras
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, Granada, Spain
| | - Nicolas Bellora
- Computational Genomics Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Eduardo Eyras
- Computational Genomics Group, Universitat Pompeu Fabra, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Javier F Cáceres
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
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40
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Zheng X, Cho S, Moon H, Loh TJ, Oh HK, Green MR, Shen H. Polypyrimidine tract binding protein inhibits IgM pre-mRNA splicing by diverting U2 snRNA base-pairing away from the branch point. RNA (NEW YORK, N.Y.) 2014; 20:440-446. [PMID: 24572809 PMCID: PMC3964906 DOI: 10.1261/rna.043737.113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 01/27/2014] [Indexed: 06/03/2023]
Abstract
The mouse immunoglobulin (IgM) pre-mRNA contains a splicing inhibitor that bears multiple binding sites for the splicing repressor polypyrimidine tract binding protein (PTB). Here we show that the inhibitor directs assembly of an ATP-dependent complex that contains PTB and U1 and U2 small nuclear RNAs (snRNAs). Unexpectedly, although U2 snRNA is present in the inhibitor complex, it is not base-paired to the branch point. We present evidence that inhibitor-bound PTB contacts U2 snRNA to promote base-pairing to an adjacent branch point-like sequence within the inhibitor, thereby preventing the U2 snRNA-branch point interaction and resulting in splicing repression. Our studies reveal a novel mechanism by which PTB represses splicing.
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Affiliation(s)
- Xuexiu Zheng
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Sunghee Cho
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Heegyum Moon
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Tiing Jen Loh
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Huyn Kyung Oh
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Michael R. Green
- Howard Hughes Medical Institute and Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Haihong Shen
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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41
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Chai Y, Liu X, Dai L, Li Y, Liu M, Zhang JY. Overexpression of HCC1/CAPERα may play a role in lung cancer carcinogenesis. Tumour Biol 2014; 35:6311-7. [PMID: 24643682 DOI: 10.1007/s13277-014-1819-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/04/2014] [Indexed: 12/22/2022] Open
Abstract
HCC1/CAPERα is considered to be a novel human tumor-associated antigen, and the tumor-specific immunity of HCC1/CAPERα has been reported in several types of cancer. However, there was very limited evidence indicating its function in tumorigenesis. In the present study, to elucidate the roles and underlying molecular mechanism of HCC1/CAPERα in lung cancer, we examined the expression of HCC1/CAPERα in human non-small cell lung cancer (NSCLC) cell line and NSCLC tissue microarray (TMA). Immunohistochemistry with TMA was performed to detect HCC1/CAPERα expression in NSCLC and adjacent lung tissues. NSCLC cell line constitutively transfected by pcDNA3.1-HCC1/CAPERα, and empty pcDNA3.1 vector were used. These cells were analyzed by Western blot, MTT, immunofluorescence, wound healing assay, and transwell assays. It was found that HCC1/CAPERα was mainly localized in the nucleus of the lung cancer cells and overexpression of HCC1/CAPERα may promote lung cancer cells proliferation and increase cells migration. The frequency of HCC1/CAPERα expression in NSCLC tissues was significantly higher than that in adjacent and normal tissues (P < 0.01). Our data suggest that overexpression of HCC1/CAPERα may increase the proliferation and migration of NSCLC cells, and HCC1/CAPERα could be a promising biomarker for lung cancer.
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Affiliation(s)
- Yurong Chai
- Department of Biological Sciences, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX, 79968, USA
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Grodecká L, Lockerová P, Ravčuková B, Buratti E, Baralle FE, Dušek L, Freiberger T. Exon first nucleotide mutations in splicing: evaluation of in silico prediction tools. PLoS One 2014; 9:e89570. [PMID: 24586880 PMCID: PMC3931810 DOI: 10.1371/journal.pone.0089570] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/21/2014] [Indexed: 12/20/2022] Open
Abstract
Mutations in the first nucleotide of exons (E+1) mostly affect pre-mRNA splicing when found in AG-dependent 3′ splice sites, whereas AG-independent splice sites are more resistant. The AG-dependency, however, may be difficult to assess just from primary sequence data as it depends on the quality of the polypyrimidine tract. For this reason, in silico prediction tools are commonly used to score 3′ splice sites. In this study, we have assessed the ability of sequence features and in silico prediction tools to discriminate between the splicing-affecting and non-affecting E+1 variants. For this purpose, we newly tested 16 substitutions in vitro and derived other variants from literature. Surprisingly, we found that in the presence of the substituting nucleotide, the quality of the polypyrimidine tract alone was not conclusive about its splicing fate. Rather, it was the identity of the substituting nucleotide that markedly influenced it. Among the computational tools tested, the best performance was achieved using the Maximum Entropy Model and Position-Specific Scoring Matrix. As a result of this study, we have now established preliminary discriminative cut-off values showing sensitivity up to 95% and specificity up to 90%. This is expected to improve our ability to detect splicing-affecting variants in a clinical genetic setting.
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Affiliation(s)
- Lucie Grodecká
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, Brno, Czech Republic
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Pavla Lockerová
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, Brno, Czech Republic
| | - Barbora Ravčuková
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, Brno, Czech Republic
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Ladislav Dušek
- Institute of Biostatistics and Analyses, Masaryk University, Brno, Czech Republic
| | - Tomáš Freiberger
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, Brno, Czech Republic
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Institute of Clinical Immunology and Allergology, St. Anne’s University Hospital and Masaryk University, Brno, Czech Republic
- * E-mail:
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43
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Roberts JM, Ennajdaoui H, Edmondson C, Wirth B, Sanford J, Chen B. Splicing factor TRA2B is required for neural progenitor survival. J Comp Neurol 2014; 522:372-92. [PMID: 23818142 PMCID: PMC3855887 DOI: 10.1002/cne.23405] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/20/2013] [Accepted: 06/21/2013] [Indexed: 01/08/2023]
Abstract
Alternative splicing of pre-mRNAs can rapidly regulate the expression of large groups of proteins. The RNA binding protein TRA2B (SFRS10) plays well-established roles in developmentally regulated alternative splicing during Drosophila sexual differentiation. TRA2B is also essential for mammalian embryogenesis and is implicated in numerous human diseases. Precise regulation of alternative splicing is critical to the development and function of the central nervous system; however, the requirements for specific splicing factors in neurogenesis are poorly understood. This study focuses on the role of TRA2B in mammalian brain development. We show that, during murine cortical neurogenesis, TRA2B is expressed in both neural progenitors and cortical projection neurons. Using cortex-specific Tra2b mutant mice, we show that TRA2B depletion results in apoptosis of the neural progenitor cells as well as disorganization of the cortical plate. Thus, TRA2B is essential for proper development of the cerebral cortex.
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Affiliation(s)
- Jacqueline M Roberts
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Hanane Ennajdaoui
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Carina Edmondson
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Brunhilde Wirth
- Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne 50931, Germany
| | - Jeremy Sanford
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Bin Chen
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
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Abstract
Alternative splicing plays a prevalent role in generating functionally diversified proteomes from genomes with a more limited repertoire of protein-coding genes. Alternative splicing is frequently regulated with cell type or developmental specificity and in response to signaling pathways, and its mis-regulation can lead to disease. Co-regulated programs of alternative splicing involve interplay between a host of cis-acting transcript features and trans-acting RNA-binding proteins. Here, we review the current state of understanding of the logic and mechanism of regulated alternative splicing and indicate how this understanding can be exploited to manipulate splicing for therapeutic purposes.
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Affiliation(s)
- Miguel B Coelho
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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45
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Jang HN, Lee M, Loh TJ, Choi SW, Oh HK, Moon H, Cho S, Hong SE, Kim DH, Sheng Z, Green MR, Park D, Zheng X, Shen H. Exon 9 skipping of apoptotic caspase-2 pre-mRNA is promoted by SRSF3 through interaction with exon 8. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1839:25-32. [PMID: 24321384 DOI: 10.1016/j.bbagrm.2013.11.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/14/2013] [Accepted: 11/26/2013] [Indexed: 01/24/2023]
Abstract
Alternative splicing plays an important role in gene expression by producing different proteins from a gene. Caspase-2 pre-mRNA produces anti-apoptotic Casp-2S and pro-apoptotic Casp-2L proteins through exon 9 inclusion or skipping. However, the molecular mechanisms of exon 9 splicing are not well understood. Here we show that knockdown of SRSF3 (also known as SRp20) with siRNA induced significant increase of endogenous exon 9 inclusion. In addition, overexpression of SRSF3 promoted exon 9 skipping. Thus we conclude that SRSF3 promotes exon 9 skipping. In order to understand the functional target of SRSF3 on caspase-2 pre-mRNA, we performed substitution and deletion mutagenesis on the potential SRSF3 binding sites that were predicted from previous reports. We demonstrate that substitution mutagenesis of the potential SRSF3 binding site on exon 8 severely disrupted the effects of SRSF3 on exon 9 skipping. Furthermore, with the approach of RNA pulldown and immunoblotting analysis we show that SRSF3 interacts with the potential SRSF3 binding RNA sequence on exon 8 but not with the mutant RNA sequence. In addition, we show that a deletion of 26nt RNA from 5' end of exon 8, a 33nt RNA from 3' end of exon 10 and a 2225nt RNA from intron 9 did not compromise the function of SRSF3 on exon 9 splicing. Therefore we conclude that SRSF3 promotes exon 9 skipping of caspase-2 pre-mRNA by interacting with exon 8. Our results reveal a novel mechanism of caspase-2 pre-mRNA splicing.
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Affiliation(s)
- Ha Na Jang
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Minho Lee
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Tiing Jen Loh
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Seung-Woo Choi
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Hyun Kyung Oh
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Heegyum Moon
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Sunghee Cho
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Seong-Eui Hong
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Do Han Kim
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Zhi Sheng
- Virginia Tech Carilion Research Institute, Roanoke, VA, 24016, USA; Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Michael R Green
- Howard Hughes Medical Institute and Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Daeho Park
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Xuexiu Zheng
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Haihong Shen
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Discovering transcription and splicing networks in myelodysplastic syndromes. PLoS One 2013; 8:e79118. [PMID: 24244432 PMCID: PMC3828332 DOI: 10.1371/journal.pone.0079118] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/17/2013] [Indexed: 11/19/2022] Open
Abstract
More and more transcription factors and their motifs have been reported and linked to specific gene expression levels. However, focusing only on transcription is not sufficient for mechanism research. Most genes, especially in eukaryotes, are alternatively spliced to different isoforms. Some of these isoforms increase the biodiversity of proteins. From this viewpoint, transcription and splicing are two of important mechanisms to modulate expression levels of isoforms. To integrate these two kinds of regulation, we built a linear regression model to select a subset of transcription factors and splicing factors for each co-expressed isoforms using least-angle regression approach. Then, we applied this method to investigate the mechanism of myelodysplastic syndromes (MDS), a precursor lesion of acute myeloid leukemia. Results suggested that expression levels of most isoforms were regulated by a set of selected regulatory factors. Some of the detected factors, such as EGR1 and STAT family, are highly correlated with progression of MDS. We discovered that the splicing factor SRSF11 experienced alternative splicing switch, and in turn induced different amino acid sequences between MDS and controls. This splicing switch causes two different splicing mechanisms. Polymerase Chain Reaction experiments also confirmed that one of its isoforms was over-expressed in MDS. We analyzed the regulatory networks constructed from the co-expressed isoforms and their regulatory factors in MDS. Many of these networks were enriched in the herpes simplex infection pathway which involves many splicing factors, and pathways in cancers and acute or chronic myeloid leukemia.
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47
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Xiang S, Gapsys V, Kim HY, Bessonov S, Hsiao HH, Möhlmann S, Klaukien V, Ficner R, Becker S, Urlaub H, Lührmann R, de Groot B, Zweckstetter M. Phosphorylation drives a dynamic switch in serine/arginine-rich proteins. Structure 2013; 21:2162-74. [PMID: 24183573 DOI: 10.1016/j.str.2013.09.014] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/25/2013] [Accepted: 09/27/2013] [Indexed: 11/25/2022]
Abstract
Serine/arginine-rich (SR) proteins are important players in RNA metabolism and are extensively phosphorylated at serine residues in RS repeats. Here, we show that phosphorylation switches the RS domain of the serine/arginine-rich splicing factor 1 from a fully disordered state to a partially rigidified arch-like structure. Nuclear magnetic resonance spectroscopy in combination with molecular dynamics simulations revealed that the conformational switch is restricted to RS repeats, critically depends on the phosphate charge state and strongly decreases the conformational entropy of RS domains. The dynamic switch also occurs in the 100 kDa SR-related protein hPrp28, for which phosphorylation at the RS repeat is required for spliceosome assembly. Thus, a phosphorylation-induced dynamic switch is common to the class of serine/arginine-rich proteins and provides a molecular basis for the functional redundancy of serine/arginine-rich proteins and the profound influence of RS domain phosphorylation on protein-protein and protein-RNA interactions.
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Affiliation(s)
- Shengqi Xiang
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
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48
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Cléry A, Sinha R, Anczuków O, Corrionero A, Moursy A, Daubner GM, Valcárcel J, Krainer AR, Allain FHT. Isolated pseudo-RNA-recognition motifs of SR proteins can regulate splicing using a noncanonical mode of RNA recognition. Proc Natl Acad Sci U S A 2013; 110:E2802-11. [PMID: 23836656 PMCID: PMC3725064 DOI: 10.1073/pnas.1303445110] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Serine/arginine (SR) proteins, one of the major families of alternative-splicing regulators in Eukarya, have two types of RNA-recognition motifs (RRMs): a canonical RRM and a pseudo-RRM. Although pseudo-RRMs are crucial for activity of SR proteins, their mode of action was unknown. By solving the structure of the human SRSF1 pseudo-RRM bound to RNA, we discovered a very unusual and sequence-specific RNA-binding mode that is centered on one α-helix and does not involve the β-sheet surface, which typically mediates RNA binding by RRMs. Remarkably, this mode of binding is conserved in all pseudo-RRMs tested. Furthermore, the isolated pseudo-RRM is sufficient to regulate splicing of about half of the SRSF1 target genes tested, and the bound α-helix is a pivotal element for this function. Our results strongly suggest that SR proteins with a pseudo-RRM frequently regulate splicing by competing with, rather than recruiting, spliceosome components, using solely this unusual RRM.
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Affiliation(s)
- Antoine Cléry
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Rahul Sinha
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Olga Anczuków
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Anna Corrionero
- Institució Catalana de Recerca i Estudis Avançats, Universitat Pompeu Fabra 08003 Barcelona, Spain; and
- Centre de Regulació Genòmica, 08003 Barcelona, Spain
| | - Ahmed Moursy
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Gerrit M. Daubner
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Juan Valcárcel
- Institució Catalana de Recerca i Estudis Avançats, Universitat Pompeu Fabra 08003 Barcelona, Spain; and
- Centre de Regulació Genòmica, 08003 Barcelona, Spain
| | | | - Frédéric H.-T. Allain
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
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49
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Regulation of splicing by SR proteins and SR protein-specific kinases. Chromosoma 2013; 122:191-207. [PMID: 23525660 DOI: 10.1007/s00412-013-0407-z] [Citation(s) in RCA: 312] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 03/04/2013] [Accepted: 03/06/2013] [Indexed: 12/21/2022]
Abstract
Genomic sequencing reveals similar but limited numbers of protein-coding genes in different genomes, which begs the question of how organismal diversities are generated. Alternative pre-mRNA splicing, a widespread phenomenon in higher eukaryotic genomes, is thought to provide a mechanism to increase the complexity of the proteome and introduce additional layers for regulating gene expression in different cell types and during development. Among a large number of factors implicated in the splicing regulation are the SR protein family of splicing factors and SR protein-specific kinases. Here, we summarize the rules for SR proteins to function as splicing regulators, which depend on where they bind in exons versus intronic regions, on alternative exons versus flanking competing exons, and on cooperative as well as competitive binding between different SR protein family members on many of those locations. We review the importance of cycles of SR protein phosphorylation/dephosphorylation in the splicing reaction with emphasis on the recent molecular insight into the role of SR protein phosphorylation in early steps of spliceosome assembly. Finally, we highlight recent discoveries of SR protein-specific kinases in transducing growth signals to regulate alternative splicing in the nucleus and the connection of both SR proteins and SR protein kinases to human diseases, particularly cancer.
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50
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Roca X, Krainer AR, Eperon IC. Pick one, but be quick: 5' splice sites and the problems of too many choices. Genes Dev 2013; 27:129-44. [PMID: 23348838 DOI: 10.1101/gad.209759.112] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Splice site selection is fundamental to pre-mRNA splicing and the expansion of genomic coding potential. 5' Splice sites (5'ss) are the critical elements at the 5' end of introns and are extremely diverse, as thousands of different sequences act as bona fide 5'ss in the human transcriptome. Most 5'ss are recognized by base-pairing with the 5' end of the U1 small nuclear RNA (snRNA). Here we review the history of research on 5'ss selection, highlighting the difficulties of establishing how base-pairing strength determines splicing outcomes. We also discuss recent work demonstrating that U1 snRNA:5'ss helices can accommodate noncanonical registers such as bulged duplexes. In addition, we describe the mechanisms by which other snRNAs, regulatory proteins, splicing enhancers, and the relative positions of alternative 5'ss contribute to selection. Moreover, we discuss mechanisms by which the recognition of numerous candidate 5'ss might lead to selection of a single 5'ss and propose that protein complexes propagate along the exon, thereby changing its physical behavior so as to affect 5'ss selection.
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Affiliation(s)
- Xavier Roca
- School of Biological Sciences, Division of Molecular Genetics and Cell Biology, Nanyang Technological University, Singapore.
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