1
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Tapescu I, Cherry S. DDX RNA helicases: key players in cellular homeostasis and innate antiviral immunity. J Virol 2024:e0004024. [PMID: 39212449 DOI: 10.1128/jvi.00040-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024] Open
Abstract
RNA helicases are integral in RNA metabolism, performing important roles in cellular homeostasis and stress responses. In particular, the DExD/H-box (DDX) helicase family possesses a conserved catalytic core that binds structural features rather than specific sequences in RNA targets. DDXs have critical roles in all aspects of RNA metabolism including ribosome biogenesis, translation, RNA export, and RNA stability. Importantly, functional specialization within this family arises from divergent N and C termini and is driven at least in part by gene duplications with 18 of the 42 human helicases having paralogs. In addition to their key roles in the homeostatic control of cellular RNA, these factors have critical roles in RNA virus infection. The canonical RIG-I-like receptors (RLRs) play pivotal roles in cytoplasmic sensing of viral RNA structures, inducing antiviral gene expression. Additional RNA helicases function as viral sensors or regulators, further diversifying the innate immune defense arsenal. Moreover, some of these helicases have been coopted by viruses to facilitate their replication. Altogether, DDX helicases exhibit functional specificity, playing intricate roles in RNA metabolism and host defense. This review will discuss the mechanisms by which these RNA helicases recognize diverse RNA structures in cellular and viral RNAs, and how this impacts RNA processing and innate immune responses.
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Affiliation(s)
- Iulia Tapescu
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Biochemistry and Biophysics Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sara Cherry
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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2
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Choquet K, Chaumont LP, Bache S, Baxter-Koenigs AR, Churchman LS. Genetic regulation of nascent RNA maturation revealed by direct RNA nanopore sequencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.29.610338. [PMID: 39257732 PMCID: PMC11383983 DOI: 10.1101/2024.08.29.610338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Quantitative trait loci analyses have revealed an important role for genetic variants in regulating alternative splicing (AS) and alternative cleavage and polyadenylation (APA) in humans. Yet, these studies are generally performed with mature mRNA, so they report on the outcome rather than the processes of RNA maturation and thus may overlook how variants directly modulate pre-mRNA processing. The order in which the many introns of a human gene are removed can substantially influence AS, while nascent RNA polyadenylation can affect RNA stability and decay. However, how splicing order and poly(A) tail length are regulated by genetic variation has never been explored. Here, we used direct RNA nanopore sequencing to investigate allele-specific pre-mRNA maturation in 12 human lymphoblastoid cell lines. We found frequent splicing order differences between alleles and uncovered significant single nucleotide polymorphism (SNP)-splicing order associations in 17 genes. This included SNPs located in or near splice sites as well as more distal intronic and exonic SNPs. Moreover, several genes showed allele-specific poly(A) tail lengths, many of which also had a skewed allelic abundance ratio. HLA class I transcripts, which encode proteins that play an essential role in antigen presentation, showed the most allele-specific splicing orders, which frequently co-occurred with allele-specific AS, APA or poly(A) tail length differences. Together, our results expose new layers of genetic regulation of pre-mRNA maturation and highlight the power of long-read RNA sequencing for allele-specific analyses.
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3
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Shine M, Gordon J, Schärfen L, Zigackova D, Herzel L, Neugebauer KM. Co-transcriptional gene regulation in eukaryotes and prokaryotes. Nat Rev Mol Cell Biol 2024; 25:534-554. [PMID: 38509203 PMCID: PMC11199108 DOI: 10.1038/s41580-024-00706-2] [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] [Accepted: 01/19/2024] [Indexed: 03/22/2024]
Abstract
Many steps of RNA processing occur during transcription by RNA polymerases. Co-transcriptional activities are deemed commonplace in prokaryotes, in which the lack of membrane barriers allows mixing of all gene expression steps, from transcription to translation. In the past decade, an extraordinary level of coordination between transcription and RNA processing has emerged in eukaryotes. In this Review, we discuss recent developments in our understanding of co-transcriptional gene regulation in both eukaryotes and prokaryotes, comparing methodologies and mechanisms, and highlight striking parallels in how RNA polymerases interact with the machineries that act on nascent RNA. The development of RNA sequencing and imaging techniques that detect transient transcription and RNA processing intermediates has facilitated discoveries of transcription coordination with splicing, 3'-end cleavage and dynamic RNA folding and revealed physical contacts between processing machineries and RNA polymerases. Such studies indicate that intron retention in a given nascent transcript can prevent 3'-end cleavage and cause transcriptional readthrough, which is a hallmark of eukaryotic cellular stress responses. We also discuss how coordination between nascent RNA biogenesis and transcription drives fundamental aspects of gene expression in both prokaryotes and eukaryotes.
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Affiliation(s)
- Morgan Shine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jackson Gordon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Leonard Schärfen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Dagmar Zigackova
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Lydia Herzel
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany.
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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4
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Pan D, Long L, Li C, Zhou Y, Liu Q, Zhao Z, Zhao H, Lin W, Zheng Z, Peng L, Li E, Xu L. Splicing factor hnRNPA1 regulates alternative splicing of LOXL2 to enhance the production of LOXL2Δ13. J Biol Chem 2024; 300:107414. [PMID: 38810697 PMCID: PMC11259713 DOI: 10.1016/j.jbc.2024.107414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 05/03/2024] [Accepted: 05/09/2024] [Indexed: 05/31/2024] Open
Abstract
Lysyl oxidase-like 2 (LOXL2) is a member of the lysyl oxidase family and has the ability to catalyze the cross-linking of extracellular matrix collagen and elastin. High expression of LOXL2 is related to tumor cell proliferation, invasion, and metastasis. LOXL2 contains 14 exons. Previous studies have found that LOXL2 has abnormal alternative splicing and exon skipping in a variety of tissues and cells, resulting in a new alternatively spliced isoform denoted LOXL2Δ13. LOXL2Δ13 lacks LOXL2WT exon 13, but its encoded protein has greater ability to induce tumor cell proliferation, invasion, and metastasis. However, the molecular events that produce LOXL2Δ13 are still unclear. In this study, we found that overexpression of the splicing factor hnRNPA1 in cells can regulate the alternative splicing of LOXL2 and increase the expression of LOXL2Δ13. The exonic splicing silencer exists at the 3' splice site and 5' splice site of LOXL2 exon 13. HnRNPA1 can bind to the exonic splicing silencer and inhibit the inclusion of exon 13. The RRM domain of hnRNPA1 and phosphorylation of hnRNPA1 at S91 and S95 are important for the regulation of LOXL2 alternative splicing. These results show that hnRNPA1 is a splicing factor that enhances the production of LOXL2Δ13.
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Affiliation(s)
- Deyuan Pan
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China; State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Xinjiang Medical University, Urumqi, China; Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Lin Long
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China; State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Xinjiang Medical University, Urumqi, China; Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Chengyu Li
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China; Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Yingxin Zhou
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China; Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Qing Liu
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Xinjiang Medical University, Urumqi, China
| | - Ziting Zhao
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Hui Zhao
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China; Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Wan Lin
- Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Zhenyuan Zheng
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China; Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Liu Peng
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China; Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Enmin Li
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China; Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China.
| | - Liyan Xu
- Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong Province, China; Institute of Basic Medical Science, Cancer Research Center, Shantou University Medical College, Shantou, Guangdong Province, China; Institute of Oncologic Pathology, Shantou University Medical College, Shantou, Guangdong Province, China.
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5
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Cao X, Zhang Y, Ding Y, Wan Y. Identification of RNA structures and their roles in RNA functions. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00748-6. [PMID: 38926530 DOI: 10.1038/s41580-024-00748-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2024] [Indexed: 06/28/2024]
Abstract
The development of high-throughput RNA structure profiling methods in the past decade has greatly facilitated our ability to map and characterize different aspects of RNA structures transcriptome-wide in cell populations, single cells and single molecules. The resulting high-resolution data have provided insights into the static and dynamic nature of RNA structures, revealing their complexity as they perform their respective functions in the cell. In this Review, we discuss recent technical advances in the determination of RNA structures, and the roles of RNA structures in RNA biogenesis and functions, including in transcription, processing, translation, degradation, localization and RNA structure-dependent condensates. We also discuss the current understanding of how RNA structures could guide drug design for treating genetic diseases and battling pathogenic viruses, and highlight existing challenges and future directions in RNA structure research.
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Affiliation(s)
- Xinang Cao
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, Singapore, Singapore
| | - Yueying Zhang
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, UK
| | - Yiliang Ding
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, UK.
| | - Yue Wan
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, Singapore, Singapore.
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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6
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Kansara S, Sawant P, Kaur T, Garg M, Pandey AK. LncRNA-mediated orchestrations of alternative splicing in the landscape of breast cancer. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195017. [PMID: 38341138 DOI: 10.1016/j.bbagrm.2024.195017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/19/2024] [Accepted: 02/03/2024] [Indexed: 02/12/2024]
Abstract
Alternative splicing (AS) is a fundamental post-transcriptional process in eukaryotes, enabling a single gene to generate diverse mRNA transcripts, thereby enhancing protein variability. This process involves the excision of introns and the joining of exons in pre-mRNA(s) to form mature mRNA. The resulting mature mRNAs exhibit various combinations of exons, contributing to functional diversity. Dysregulation of AS can substantially modulate protein functions, impacting the onset and progression of numerous diseases, including cancer. Non-coding RNAs (ncRNAs) are distinct from protein-coding RNAs and consist of short and long types. Long non-coding RNAs (lncRNAs) play an important role in regulating several cellular processes, particularly alternative splicing, according to new research. This review provides insight into the latest discoveries concerning how lncRNAs influence alternative splicing within the realm of breast cancer. Additionally, it explores potential therapeutic strategies focused on targeting lncRNAs.
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Affiliation(s)
- Samarth Kansara
- Amity Institute of Biotechnology, Amity University Haryana, Panchgaon, Manesar, Haryana 122413, India
| | - Prajwali Sawant
- Amity Institute of Biotechnology, Amity University Haryana, Panchgaon, Manesar, Haryana 122413, India
| | - Taranjeet Kaur
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, 382355, Gujarat, India
| | - Manoj Garg
- Amity Institute of Molecular Medicine and Stem Cell Research (AIMMSCR), Amity University, Uttar Pradesh, Sector-125, Noida 201313, India
| | - Amit Kumar Pandey
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, 382355, Gujarat, India.
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7
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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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8
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Tompkins VS, Xue Z, Peterson JM, Rouse WB, O’Leary CA, Moss WN. Identification of MYC intron 2 regions that modulate expression. PLoS One 2024; 19:e0296889. [PMID: 38236931 PMCID: PMC10795982 DOI: 10.1371/journal.pone.0296889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 12/19/2023] [Indexed: 01/22/2024] Open
Abstract
MYC pre-mRNA is spliced with high fidelity to produce the transcription factor known to regulate cellular differentiation, proliferation, apoptosis, and alternative splicing. The mechanisms underpinning the pre-mRNA splicing of MYC, however, remain mostly unexplored. In this study, we examined the interaction of heterogeneous nuclear ribonucleoprotein C (HNRNPC) with MYC intron 2. Building off published eCLIP studies, we confirmed this interaction with poly(U) regions in intron 2 of MYC and found that full binding is correlated with optimal protein production. The interaction appears to be compensatory, as mutational disruption of all three poly(U) regions was required to reduce both HNRNPC binding capacity and fidelity of either splicing or translation. Poly(U) sequences in MYC intron 2 were relatively conserved across sequences from several different species. Lastly, we identified a short sequence just upstream of an HNRNPC binding region that when removed enhances MYC translation.
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Affiliation(s)
- Van S. Tompkins
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
| | - Zheng Xue
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
| | - Jake M. Peterson
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
| | - Warren B. Rouse
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
| | - Collin A. O’Leary
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
| | - Walter N. Moss
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
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9
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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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10
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Taylor J, Weiss SM, Marshall PJ. Genes, genomes, and developmental process. Behav Brain Sci 2023; 46:e204. [PMID: 37694896 DOI: 10.1017/s0140525x22002199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The view advanced by Madole & Harden falls back on the dogma of a gene as a DNA sequence that codes for a fixed product with an invariant function regardless of temporal and spatial contexts. This outdated perspective entrenches the metaphor of genes as static units of information and glosses over developmental complexities.
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Affiliation(s)
| | - Staci Meredith Weiss
- Perinatal Imaging Partnership, Rosie Maternity Hospital, Cambridge, UK https://www.repro.cam.ac.uk/staff/dr-staci-meredith-weiss
- Department of Psychology, University of Cambridge, UK
| | - Peter J Marshall
- Department of Psychology & Neuroscience, Temple University, Philadelphia, PA, USA https://sites.temple.edu/peterjmarshall/
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11
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Covello G, Siva K, Adami V, Denti MA. HCS-Splice: A High-Content Screening Method to Advance the Discovery of RNA Splicing-Modulating Therapeutics. Cells 2023; 12:1959. [PMID: 37566038 PMCID: PMC10417277 DOI: 10.3390/cells12151959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/10/2023] [Accepted: 07/13/2023] [Indexed: 08/12/2023] Open
Abstract
Nucleic acid therapeutics have demonstrated an impressive acceleration in recent years. They work through multiple mechanisms of action, including the downregulation of gene expression and the modulation of RNA splicing. While several drugs based on the former mechanism have been approved, few target the latter, despite the promise of RNA splicing modulation. To improve our ability to discover novel RNA splicing-modulating therapies, we developed HCS-Splice, a robust cell-based High-Content Screening (HCS) assay. By implementing the use of a two-colour (GFP/RFP) fluorescent splicing reporter plasmid, we developed a versatile, effective, rapid, and robust high-throughput strategy for the identification of potent splicing-modulating molecules. The HCS-Splice strategy can also be used to functionally confirm splicing mutations in human genetic disorders or to screen drug candidates. As a proof-of-concept, we introduced a dementia-related splice-switching mutation in the Microtubule-Associated Protein Tau (MAPT) exon 10 splicing reporter. We applied HCS-Splice to the wild-type and mutant reporters and measured the functional change in exon 10 inclusion. To demonstrate the applicability of the method in cell-based drug discovery, HCS-Splice was used to evaluate the efficacy of an exon 10-targeting siRNA, which was able to restore the correct alternative splicing balance.
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Affiliation(s)
- Giuseppina Covello
- RNA Biology and Biotechnology Laboratory, Department of Cellular, Computational and Integrative Biology—CIBIO, University of Trento, 38123 Trento, Italy;
| | - Kavitha Siva
- RNA Biology and Biotechnology Laboratory, Department of Cellular, Computational and Integrative Biology—CIBIO, University of Trento, 38123 Trento, Italy;
| | - Valentina Adami
- High Throughput Screening and Validation Core Facility (HTS), Department of Cellular, Computational and Integrative Biology—CIBIO, University of Trento, 38123 Trento, Italy;
| | - Michela Alessandra Denti
- RNA Biology and Biotechnology Laboratory, Department of Cellular, Computational and Integrative Biology—CIBIO, University of Trento, 38123 Trento, Italy;
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12
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Haque N, Will A, Cook AG, Hogg JR. A network of DZF proteins controls alternative splicing regulation and fidelity. Nucleic Acids Res 2023; 51:6411-6429. [PMID: 37144502 PMCID: PMC10325889 DOI: 10.1093/nar/gkad351] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 04/12/2023] [Accepted: 05/03/2023] [Indexed: 05/06/2023] Open
Abstract
Proteins containing DZF (domain associated with zinc fingers) modules play important roles throughout gene expression, from transcription to translation. Derived from nucleotidyltransferases but lacking catalytic residues, DZF domains serve as heterodimerization surfaces between DZF protein pairs. Three DZF proteins are widely expressed in mammalian tissues, ILF2, ILF3 and ZFR, which form mutually exclusive ILF2-ILF3 and ILF2-ZFR heterodimers. Using eCLIP-Seq, we find that ZFR binds across broad intronic regions to regulate the alternative splicing of cassette and mutually exclusive exons. ZFR preferentially binds dsRNA in vitro and is enriched on introns containing conserved dsRNA elements in cells. Many splicing events are similarly altered upon depletion of any of the three DZF proteins; however, we also identify independent and opposing roles for ZFR and ILF3 in alternative splicing regulation. Along with widespread involvement in cassette exon splicing, the DZF proteins control the fidelity and regulation of over a dozen highly validated mutually exclusive splicing events. Our findings indicate that the DZF proteins form a complex regulatory network that leverages dsRNA binding by ILF3 and ZFR to modulate splicing regulation and fidelity.
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Affiliation(s)
- Nazmul Haque
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD20892, USA
| | - Alexander Will
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Atlanta G Cook
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - J Robert Hogg
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD20892, USA
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13
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Busselez J, Uzbekov RE, Franco B, Pancione M. New insights into the centrosome-associated spliceosome components as regulators of ciliogenesis and tissue identity. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1776. [PMID: 36717357 DOI: 10.1002/wrna.1776] [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] [Received: 06/06/2022] [Revised: 12/20/2022] [Accepted: 12/27/2022] [Indexed: 02/01/2023]
Abstract
Biomolecular condensates are membrane-less assemblies of proteins and nucleic acids. Centrosomes are biomolecular condensates that play a crucial role in nuclear division, cytoskeletal remodeling, and cilia formation in animal cells. Spatial omics technology is providing new insights into the dynamic exchange of spliceosome components between the nucleus and the centrosome/cilium. Intriguingly, centrosomes are emerging as cytoplasmic sites for information storage, enriched with RNA molecules and RNA-processing proteins. Furthermore, growing evidence supports the view that nuclear spliceosome components assembled at the centrosome function as potential coordinators of splicing subprograms, pluripotency, and cell differentiation. In this article, we first discuss the current understanding of the centrosome/cilium complex, which controls both stem cell differentiation and pluripotency. We next explore the molecular mechanisms that govern splicing factor assembly and disassembly around the centrosome and examine how RNA processing pathways contribute to ciliogenesis. Finally, we discuss numerous unresolved compelling questions regarding the centrosome-associated spliceosome components and transcript variants within the cytoplasm as sources of RNA-based secondary messages in the regulation of cell identity and cell fate determination. This article is categorized under: RNA-Based Catalysis > RNA Catalysis in Splicing and Translation RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Processing > Splicing Regulation/Alternative Splicing RNA Processing > RNA Processing.
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Affiliation(s)
- Johan Busselez
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch-Graffenstaden, France
| | - Rustem E Uzbekov
- Faculté de Médecine, Université de Tours, Tours, France
- Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, Russia
| | - Brunella Franco
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
- Department of Translational Medicine, Medical Genetics, University of Naples "Federico II", Naples, Italy
- Scuola Superiore Meridionale (SSM, School of Advanced Studies), Genomics and Experimental Medicine program, University of Naples Federico II, Naples, Italy
| | - Massimo Pancione
- Department of Sciences and Technologies, University of Sannio, Benevento, Italy
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University Madrid, Madrid, Spain
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14
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Zabardast A, Tamer EG, Son YA, Yılmaz A. An automated framework for evaluation of deep learning models for splice site predictions. Sci Rep 2023; 13:10221. [PMID: 37353532 PMCID: PMC10290104 DOI: 10.1038/s41598-023-34795-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 05/08/2023] [Indexed: 06/25/2023] Open
Abstract
A novel framework for the automated evaluation of various deep learning-based splice site detectors is presented. The framework eliminates time-consuming development and experimenting activities for different codebases, architectures, and configurations to obtain the best models for a given RNA splice site dataset. RNA splicing is a cellular process in which pre-mRNAs are processed into mature mRNAs and used to produce multiple mRNA transcripts from a single gene sequence. Since the advancement of sequencing technologies, many splice site variants have been identified and associated with the diseases. So, RNA splice site prediction is essential for gene finding, genome annotation, disease-causing variants, and identification of potential biomarkers. Recently, deep learning models performed highly accurately for classifying genomic signals. Convolutional Neural Network (CNN), Long Short-Term Memory (LSTM) and its bidirectional version (BLSTM), Gated Recurrent Unit (GRU), and its bidirectional version (BGRU) are promising models. During genomic data analysis, CNN's locality feature helps where each nucleotide correlates with other bases in its vicinity. In contrast, BLSTM can be trained bidirectionally, allowing sequential data to be processed from forward and reverse directions. Therefore, it can process 1-D encoded genomic data effectively. Even though both methods have been used in the literature, a performance comparison was missing. To compare selected models under similar conditions, we have created a blueprint for a series of networks with five different levels. As a case study, we compared CNN and BLSTM models' learning capabilities as building blocks for RNA splice site prediction in two different datasets. Overall, CNN performed better with [Formula: see text] accuracy ([Formula: see text] improvement), [Formula: see text] F1 score ([Formula: see text] improvement), and [Formula: see text] AUC-PR ([Formula: see text] improvement) in human splice site prediction. Likewise, an outperforming performance with [Formula: see text] accuracy ([Formula: see text] improvement), [Formula: see text] F1 score ([Formula: see text] improvement), and [Formula: see text] AUC-PR ([Formula: see text] improvement) is achieved in C. elegans splice site prediction. Overall, our results showed that CNN learns faster than BLSTM and BGRU. Moreover, CNN performs better at extracting sequence patterns than BLSTM and BGRU. To our knowledge, no other framework is developed explicitly for evaluating splice detection models to decide the best possible model in an automated manner. So, the proposed framework and the blueprint would help selecting different deep learning models, such as CNN vs. BLSTM and BGRU, for splice site analysis or similar classification tasks and in different problems.
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Affiliation(s)
- Amin Zabardast
- Department of Health Informatics, Graduate School of Informatics, Middle East Technical University, Ankara, Turkey
| | - Elif Güney Tamer
- Department of Health Informatics, Graduate School of Informatics, Middle East Technical University, Ankara, Turkey
| | - Yeşim Aydın Son
- Department of Health Informatics, Graduate School of Informatics, Middle East Technical University, Ankara, Turkey
| | - Arif Yılmaz
- Institute of Data Science, Maastricht University, Maastricht, The Netherlands.
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15
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Balaratnam S, Torrey ZR, Calabrese DR, Banco MT, Yazdani K, Liang X, Fullenkamp CR, Seshadri S, Holewinski RJ, Andresson T, Ferré-D'Amaré AR, Incarnato D, Schneekloth JS. Investigating the NRAS 5' UTR as a target for small molecules. Cell Chem Biol 2023; 30:643-657.e8. [PMID: 37257453 DOI: 10.1016/j.chembiol.2023.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/24/2023] [Accepted: 05/10/2023] [Indexed: 06/02/2023]
Abstract
Neuroblastoma RAS (NRAS) is an oncogene that is deregulated and highly mutated in cancers including melanomas and acute myeloid leukemias. The 5' untranslated region (UTR) (5' UTR) of the NRAS mRNA contains a G-quadruplex (G4) that regulates translation. Here we report a novel class of small molecule that binds to the G4 structure located in the 5' UTR of the NRAS mRNA. We used a small molecule microarray screen to identify molecules that selectively bind to the NRAS-G4 with submicromolar affinity. One compound inhibits the translation of NRAS in vitro but showed only moderate effects on the NRAS levels in cellulo. Rapid Amplification of cDNA Ends and RT-PCR analysis revealed that the predominant NRAS transcript does not possess the G4 structure. Thus, although NRAS transcripts lack a G4 in many cell lines the concept of targeting folded regions within 5' UTRs to control translation remains a highly attractive strategy.
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Affiliation(s)
- Sumirtha Balaratnam
- Chemical Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Zachary R Torrey
- Chemical Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - David R Calabrese
- Chemical Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Michael T Banco
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD 20892, USA
| | - Kamyar Yazdani
- Chemical Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Xiao Liang
- Chemical Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | | | - Srinath Seshadri
- Chemical Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Ronald J Holewinski
- Protein Characterization Laboratory, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc, Frederick, MD 21702, USA
| | - Thorkell Andresson
- Protein Characterization Laboratory, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc, Frederick, MD 21702, USA
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD 20892, USA
| | - Danny Incarnato
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, the Netherlands
| | - John S Schneekloth
- Chemical Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA.
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16
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Chen QW, Cai QQ, Yang Y, Dong S, Liu YY, Chen ZY, Kang CL, Qi B, Dong YW, Wu W, Zhuang LP, Shen YH, Meng ZQ, Wu XZ. LncRNA BC promotes lung adenocarcinoma progression by modulating IMPAD1 alternative splicing. Clin Transl Med 2023; 13:e1129. [PMID: 36650118 PMCID: PMC9845120 DOI: 10.1002/ctm2.1129] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The therapeutic value of targeted therapies in patients with lung cancer is reduced when tumours acquire secondary resistance after an initial period of successful treatment. However, the molecular events behind the resistance to targeted therapies in lung cancer remain largely unknown. AIMS To discover the important role and mechanism of lncRNA BC in promoting tumor metastasis and influencing clinical prognosis of LUAD. MATERIALS & METHODS Microarrays were used to screen a comprehensive set of lncRNAs with differential expression profiles in lung cancer cells. The functional role and mechanism of lncRNA were further investigated by gain- and loss-of-function assays. RNA pull-down, protein assays, and mass spectrometry were used to identify proteins that interacted with lncRNA. TaqMan PCR was used to measure lncRNA in lung adenocarcinoma and adjacent nontumor tissues from 428 patients. The clinical significance of lncRNA identified was statistically confirmed in this cohort of patients. RESULTS In this study, we show that the long non-coding RNA BC009639 (BC) is involved in acquired resistance to EGFR-targeted therapies. Among the 235 long non-coding RNAs that were differentially expressed in lung cancer cell lines, with different metastatic potentials, BC promoted growth, invasion, metastasis, and resistance to EGFR-tyrosine kinase inhibitors (EGFR-TKIs), both in vitro and in vivo. BC was highly expressed in 428 patients with lung adenocarcinoma (LUAD) and high BC expression correlated with reduced efficacy of EGFR-TKI therapy. To uncover the molecular mechanism of BC-mediated EGFR-TKI resistance in lung cancer, we screened and identified nucleolin and hnRNPK that interact with BC. BC formed the splicing complex with nucleolin and hnRNPK to facilitate the production of a non-protein-coding inositol monophosphatase domain containing 1 (IMPAD1) splice variant, instead of the protein-coding variant. The BC-mediated alternative splicing (AS) of IMPAD1 resulted in the induction of the epithelial-mesenchymal transition and resistance to EGFR-TKI in lung cancer. High BC expression correlated with clinical progress and poor survival among 402 patients with LUAD. DISSCUSSION Through alternative splicing, BC boosted the non-coding IMPAD1-203 transcript variant while suppressing the IMPAD1-201 variant. In order to control the processing of pre-mRNA, BC not only attracted RNA binding proteins (NCL, IGF2BP1) or splicing factors (hnRNPK), but also controlled the formation of the splicing-regulator complex by creating RNA-RNA-duplexes. CONCLUSION Our results reveal an important role for BC in mediating resistance to EGFR-targeted therapy in LUAD through IMPAD1 AS and in implication for the targeted therapy resistance.
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Affiliation(s)
- Qi Wen Chen
- Department of Integrative OncologyFudan University Shanghai Cancer CenterShanghaiP. R. China
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiP. R. China
| | - Qian Qian Cai
- Shanghai Key Laboratory of Molecular ImagingShanghai University of Medicine and Health SciencesShanghaiP. R. China
| | - Ying Yang
- Key Laboratory of Glycoconjugate Research Ministry of Public Health, Department of Biochemistry and Molecular Biology, School of Basic Medical SciencesFudan UniversityShanghaiP. R. China
| | - Shu Dong
- Department of Integrative OncologyFudan University Shanghai Cancer CenterShanghaiP. R. China
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiP. R. China
| | - Yuan Yuan Liu
- Key Laboratory of Glycoconjugate Research Ministry of Public Health, Department of Biochemistry and Molecular Biology, School of Basic Medical SciencesFudan UniversityShanghaiP. R. China
| | - Zhong Yi Chen
- Key Laboratory of Glycoconjugate Research Ministry of Public Health, Department of Biochemistry and Molecular Biology, School of Basic Medical SciencesFudan UniversityShanghaiP. R. China
| | - Chun Lan Kang
- Key Laboratory of Glycoconjugate Research Ministry of Public Health, Department of Biochemistry and Molecular Biology, School of Basic Medical SciencesFudan UniversityShanghaiP. R. China
| | - Bing Qi
- Key Laboratory of Glycoconjugate Research Ministry of Public Health, Department of Biochemistry and Molecular Biology, School of Basic Medical SciencesFudan UniversityShanghaiP. R. China
| | - Yi Wei Dong
- Key Laboratory of Glycoconjugate Research Ministry of Public Health, Department of Biochemistry and Molecular Biology, School of Basic Medical SciencesFudan UniversityShanghaiP. R. China
| | - Wei Wu
- Department of PathologyShanghai Pulmonary Hospital, Tongji University School of MedicineShanghaiP. R. China
| | - Li Ping Zhuang
- Department of Integrative OncologyFudan University Shanghai Cancer CenterShanghaiP. R. China
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiP. R. China
| | - Ye Hua Shen
- Department of Integrative OncologyFudan University Shanghai Cancer CenterShanghaiP. R. China
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiP. R. China
| | - Zhi Qiang Meng
- Department of Integrative OncologyFudan University Shanghai Cancer CenterShanghaiP. R. China
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiP. R. China
| | - Xing Zhong Wu
- Key Laboratory of Glycoconjugate Research Ministry of Public Health, Department of Biochemistry and Molecular Biology, School of Basic Medical SciencesFudan UniversityShanghaiP. R. China
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17
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Jones AN, Graß C, Meininger I, Geerlof A, Klostermann M, Zarnack K, Krappmann D, Sattler M. Modulation of pre-mRNA structure by hnRNP proteins regulates alternative splicing of MALT1. SCIENCE ADVANCES 2022; 8:eabp9153. [PMID: 35921415 PMCID: PMC9348792 DOI: 10.1126/sciadv.abp9153] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Alternative splicing plays key roles for cell type-specific regulation of protein function. It is controlled by cis-regulatory RNA elements that are recognized by RNA binding proteins (RBPs). The MALT1 paracaspase is a key factor of signaling pathways that mediate innate and adaptive immune responses. Alternative splicing of MALT1 is critical for controlling optimal T cell activation. We demonstrate that MALT1 splicing depends on RNA structural elements that sequester the splice sites of the alternatively spliced exon7. The RBPs hnRNP U and hnRNP L bind competitively to stem-loop RNA structures that involve the 5' and 3' splice sites flanking exon7. While hnRNP U stabilizes RNA stem-loop conformations that maintain exon7 skipping, hnRNP L disrupts these RNA elements to facilitate recruitment of the essential splicing factor U2AF2, thereby promoting exon7 inclusion. Our data represent a paradigm for the control of splice site selection by differential RBP binding and modulation of pre-mRNA structure.
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Affiliation(s)
- Alisha N. Jones
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, 85748 München, Germany
| | - Carina Graß
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Isabel Meininger
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Arie Geerlof
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Melina Klostermann
- Buchmann Institute for Molecular Life Sciences (BMLS) & Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS) & Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Daniel Krappmann
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Corresponding author. (D.K.); (M.S.)
| | - Michael Sattler
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, 85748 München, Germany
- Corresponding author. (D.K.); (M.S.)
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18
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Vorländer MK, Pacheco-Fiallos B, Plaschka C. Structural basis of mRNA maturation: Time to put it together. Curr Opin Struct Biol 2022; 75:102431. [PMID: 35930970 DOI: 10.1016/j.sbi.2022.102431] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 06/02/2022] [Accepted: 06/14/2022] [Indexed: 11/27/2022]
Abstract
In eukaryotes, the expression of genetic information begins in the cell nucleus with precursor messenger RNA (pre-mRNA) transcription and processing into mature mRNA. The mRNA is subsequently recognized and packaged by proteins into an mRNA ribonucleoprotein complex (mRNP) and exported to the cytoplasm for translation. Each of the nuclear mRNA maturation steps is carried out by a dedicated molecular machine. Here, we highlight recent structural and mechanistic insights into how these machines function, including the capping enzyme, the spliceosome, the 3'-end processing machinery, and the transcription-export complex. While we increasingly understand individual steps of nuclear gene expression, many questions remain. For example, we are only beginning to reveal how mature mRNAs are recognized and packaged for nuclear export and how mRNA maturation events are coupled to transcription and to each other. Advances in the preparation of recombinant and endogenous protein-nucleic acid complexes, cryo-electron microscopy, and machine learning promise exciting insights into the mechanisms of nuclear gene expression and its spatial organization.
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Affiliation(s)
- Matthias K Vorländer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria. https://twitter.com/@MVorlandr
| | - Belén Pacheco-Fiallos
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030, Vienna, Austria. https://twitter.com/@bpachecofiallos
| | - Clemens Plaschka
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria.
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19
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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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20
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Shao C, Cai F, Zhang Y, Bao Z, Shi G, Bao M, Zhang J. Regulation of alternative splicing of PaFT and PaFDL1, the FT and FD homologs in Platanus acerifolia. Gene 2022; 830:146506. [PMID: 35447236 DOI: 10.1016/j.gene.2022.146506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/16/2022] [Accepted: 04/14/2022] [Indexed: 11/04/2022]
Abstract
Alternative splicing (AS) selects different alternative splice sites and produces a variety of transcripts with different exon/intron combinations, which may result in multiple protein isoforms. The splicing signals include cis-elements and RNA structures; however, the mechanisms of AS regulation in plants have yet to be elucidated. Previous studies have shown that in Platanus acerifolia, the FLOWERING LOCUS T (FT) homolog PaFT has a unique and complex AS pattern, in which most of the splice forms of PaFT involve the first and/or second intron, and the FD homolog PaFDL1 produces two transcripts via AS, whereas the other FT homolog PaFTL is not regulated by AS. In this study, the regulatory mechanism of the AS of PaFT was demonstrated to be conserved in different plant species. To define the distribution of the AS regulatory signals, the intron-swap, site-directed mutagenesis of alternative splice sites, and deletion experiment were performed. For the PaFT gene, all the signals that regulate the AS of the first intron were located within this intron, while the usage of the first alternative splice site in the second intron was determined by the first intron. Meanwhile, the AS of PaFDL1 might be co-regulated by exons and the first intron. Additionally, the first alternative splice site and adjacent region in PaFT intron 1 might contain cis-elements and/or RNA structures that affect the use of the other sites. This study had provided a deeper insight into the distribution of AS signals in plants, namely the AS signals of different splice sites might exist in the intron where the sites were present, and might also be distributed in exons or other introns.
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Affiliation(s)
- Changsheng Shao
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
| | - Fangfang Cai
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Present address: Plant Genomics & Molecular Improvement of Colored Fiber Laboratory, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China.
| | - Yanping Zhang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
| | - Zhiru Bao
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
| | - Gehui Shi
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
| | - Manzhu Bao
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
| | - Jiaqi Zhang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
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21
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Ding F, Su CJ, Edmonds KK, Liang G, Elowitz MB. Dynamics and functional roles of splicing factor autoregulation. Cell Rep 2022; 39:110985. [PMID: 35732114 PMCID: PMC9262138 DOI: 10.1016/j.celrep.2022.110985] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 02/01/2022] [Accepted: 05/31/2022] [Indexed: 11/29/2022] Open
Abstract
Non-core spliceosome components are essential, conserved regulators of alternative splicing. They provide concentration-dependent control of diverse pre-mRNAs. Many splicing factors direct unproductive splicing of their own pre-mRNAs through negative autoregulation. However, the impact of such feedback loops on splicing dynamics at the single-cell level remains unclear. Here, we developed a system to quantitatively analyze negative autoregulatory splicing dynamics by splicing factor SRSF1 in response to perturbations in single HEK293 cells. We show that negative autoregulatory splicing provides critical functions for gene regulation, establishing a ceiling of SRSF1 protein concentration, reducing cell-cell heterogeneity in SRSF1 levels, and buffering variation in transcription. Most important, it adapts SRSF1 splicing activity to variations in demand from other pre-mRNA substrates. A minimal mathematical model of autoregulatory splicing explains these experimentally observed features and provides values for effective biochemical parameters. These results reveal the unique functional roles that splicing negative autoregulation plays in homeostatically regulating transcriptional programs.
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Affiliation(s)
- Fangyuan Ding
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute; Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, USA; Center for Synthetic Biology, Center for Complex Biological Systems, Chao Family Comprehensive Cancer Center, Department of Developmental and Cell Biology, and Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA 92697, USA.
| | - Christina J Su
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - KeHuan Kuo Edmonds
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Guohao Liang
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, USA
| | - Michael B Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute.
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22
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G R, Mitra A, Pk V. Predicting functional riboSNitches in the context of alternative splicing. Gene X 2022; 837:146694. [PMID: 35738445 DOI: 10.1016/j.gene.2022.146694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 05/11/2022] [Accepted: 06/17/2022] [Indexed: 11/19/2022] Open
Abstract
RNAs are the major regulators of gene expression, and their secondary structures play crucial roles at different levels. RiboSNitches are disease-associated SNPs that cause changes in the pre-mRNA secondary structural ensemble. Several riboSNitches have been detected in the 5' and 3' untranslated regions and lncRNA. Although cases of secondary structural elements playing a regulatory role in alternative splicing are known, regions specific to splicing events, such as splice junctions have not received much attention. We tested splice-site mutations for their efficiency in disrupting the secondary structure and hypothesized that these could play a crucial role in alternative splicing. Multiple riboSNitch prediction methods were applied to obtain overlapping results that are potentially more reliable. Putative riboSNitches were identified from aberrant 5' and 3' splice site mutations, cancer-causing somatic mutations, and genes that harbor the regulatory RNA secondary structural elements. Our workflow for predicting riboSNitches associated with alternative splicing is novel and paves the way for subsequent experimental validation.
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Affiliation(s)
- Ramya G
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India.
| | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India.
| | - Vinod Pk
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India.
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23
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Kumar J, Lackey L, Waldern JM, Dey A, Mustoe AM, Weeks KM, Mathews DH, Laederach A. Quantitative prediction of variant effects on alternative splicing in MAPT using endogenous pre-messenger RNA structure probing. eLife 2022; 11:73888. [PMID: 35695373 PMCID: PMC9236610 DOI: 10.7554/elife.73888] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 06/12/2022] [Indexed: 11/29/2022] Open
Abstract
Splicing is highly regulated and is modulated by numerous factors. Quantitative predictions for how a mutation will affect precursor mRNA (pre-mRNA) structure and downstream function are particularly challenging. Here, we use a novel chemical probing strategy to visualize endogenous precursor and mature MAPT mRNA structures in cells. We used these data to estimate Boltzmann suboptimal structural ensembles, which were then analyzed to predict consequences of mutations on pre-mRNA structure. Further analysis of recent cryo-EM structures of the spliceosome at different stages of the splicing cycle revealed that the footprint of the Bact complex with pre-mRNA best predicted alternative splicing outcomes for exon 10 inclusion of the alternatively spliced MAPT gene, achieving 74% accuracy. We further developed a β-regression weighting framework that incorporates splice site strength, RNA structure, and exonic/intronic splicing regulatory elements capable of predicting, with 90% accuracy, the effects of 47 known and 6 newly discovered mutations on inclusion of exon 10 of MAPT. This combined experimental and computational framework represents a path forward for accurate prediction of splicing-related disease-causing variants.
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Affiliation(s)
- Jayashree Kumar
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Lela Lackey
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Department of Genetics and Biochemistry, Center for Human Genetics, Clemson University, Greenwood, United States
| | - Justin M Waldern
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Abhishek Dey
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Anthony M Mustoe
- Verna and Marrs McClean Department of Biochemistry and Molecular Biology, Therapeutic Innovation Center (THINC), and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Kevin M Weeks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - David H Mathews
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, United States
| | - Alain Laederach
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
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24
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Georgakopoulos-Soares I, Parada GE, Hemberg M. Secondary structures in RNA synthesis, splicing and translation. Comput Struct Biotechnol J 2022; 20:2871-2884. [PMID: 35765654 PMCID: PMC9198270 DOI: 10.1016/j.csbj.2022.05.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/19/2022] [Accepted: 05/21/2022] [Indexed: 11/30/2022] Open
Abstract
Even though the functional role of mRNA molecules is primarily decided by the nucleotide sequence, several properties are determined by secondary structure conformations. Examples of secondary structures include long range interactions, hairpins, R-loops and G-quadruplexes and they are formed through interactions of non-adjacent nucleotides. Here, we discuss advances in our understanding of how secondary structures can impact RNA synthesis, splicing, translation and mRNA half-life. During RNA synthesis, secondary structures determine RNA polymerase II (RNAPII) speed, thereby influencing splicing. Splicing is also determined by RNA binding proteins and their binding rates are modulated by secondary structures. For the initiation of translation, secondary structures can control the choice of translation start site. Here, we highlight the mechanisms by which secondary structures modulate these processes, discuss advances in technologies to detect and study them systematically, and consider the roles of RNA secondary structures in disease.
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Affiliation(s)
- Ilias Georgakopoulos-Soares
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Guillermo E. Parada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5A 1A8, Canada
| | - Martin Hemberg
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, Boston, MA, USA
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25
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Thonda S, Vinnakota RL, Kona SV, Kalivendi SV. Identification of RBMX as a splicing regulator in Parkinsonian mimetic induced alternative splicing of α-synuclein. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194825. [PMID: 35577270 DOI: 10.1016/j.bbagrm.2022.194825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/28/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
α-Synuclein (α-syn) plays a precipitating role in Parkinson's disease (PD) due to its tendency to form oligomers and fibrils. The presence of smaller isoforms of α-syn was widely noticed in the affected brain regions of PD patients. 112-synuclein (112-syn) which lacks exon-5, possess enhanced aggregation propensity and forms intracellular inclusions. However, the factors responsible for the skipping of exon-5 are not completely understood. In this context, we aimed to identity the cis & trans-acting elements governing alternative splicing (AS) events by the Parkinsonian agent (MPP+) using minigene constructs. Minigene-I and -II were constructed by pruning the intron-4 and -5 regions respectively without altering the branch point adenosine to preserve splicing machinery. Also, chimeric minigenes were engineered by replacing either 5' (Mini-III) or 3' (Mini-IV) flanking intronic regions of exon-5 with other intronic regions (intron-3 and -2) that are not responsive to MPP+ induced splicing. While all the above minigenes exhibited MPP+-induced skipping of exon-5, Minigene-III did not generate the spliced product indicating that the 5' flanking intronic region (316 bp) of exon-5 possess cis-acting elements responsible for oxidant-induced alternative splicing. RNA-Binding Protein Database (RBDP) analysis revealed the presence of four putative RNA binding proteins (RBPs), namely, RBMX, MBNL1, KHDRBS3 and SFRS1 that may bind to the 316 bp region of intron-4and their expression was substantially reduced following MPP+ treatment. Further, overexpression of RBMX mitigated MPP+-induced generation of 112-syn and also reduced intracellular α-syn aggregates. Overall, our study identified the pivotal role of the splicing regulator, RBMX, in the pathophysiology of PD.
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Affiliation(s)
- Swaroop Thonda
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ravali L Vinnakota
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Swathi V Kona
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shasi V Kalivendi
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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26
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Li H, Eksi R, Yi D, Godfrey B, Mathew LR, O’Connor CL, Bitzer M, Kretzler M, Menon R, Guan Y. Micro-dissection and integration of long and short reads to create a robust catalog of kidney compartment-specific isoforms. PLoS Comput Biol 2022; 18:e1010040. [PMID: 35468141 PMCID: PMC9037928 DOI: 10.1371/journal.pcbi.1010040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 03/19/2022] [Indexed: 11/19/2022] Open
Abstract
Studying isoform expression at the microscopic level has always been a challenging task. A classical example is kidney, where glomerular and tubulo-interstitial compartments carry out drastically different physiological functions and thus presumably their isoform expression also differs. We aim at developing an experimental and computational pipeline for identifying isoforms at microscopic structure-level. We microdissected glomerular and tubulo-interstitial compartments from healthy human kidney tissues from two cohorts. The two compartments were separately sequenced with the PacBio RS II platform. These transcripts were then validated using transcripts of the same samples by the traditional Illumina RNA-Seq protocol, distinct Illumina RNA-Seq short reads from European Renal cDNA Bank (ERCB) samples, and annotated GENCODE transcript list, thus identifying novel transcripts. We identified 14,739 and 14,259 annotated transcripts, and 17,268 and 13,118 potentially novel transcripts in the glomerular and tubulo-interstitial compartments, respectively. Of note, relying solely on either short or long reads would have resulted in many erroneous identifications. We identified distinct pathways involved in glomerular and tubulo-interstitial compartments at the isoform level, creating an important experimental and computational resource for the kidney research community.
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Affiliation(s)
- Hongyang Li
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Ridvan Eksi
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Daiyao Yi
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Bradley Godfrey
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lisa R. Mathew
- Harvard College, Cambridge, Massachusetts, United States of America
| | - Christopher L. O’Connor
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Markus Bitzer
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Matthias Kretzler
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Rajasree Menon
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (RM); (YG)
| | - Yuanfang Guan
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (RM); (YG)
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27
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Sergeeva OV, Shcherbinina EY, Shomron N, Zatsepin TS. Modulation of RNA Splicing by Oligonucleotides: Mechanisms of Action and Therapeutic Implications. Nucleic Acid Ther 2022; 32:123-138. [PMID: 35166605 DOI: 10.1089/nat.2021.0067] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dysregulation of RNA splicing causes many diseases and disorders. Several therapeutic approaches have been developed to correct aberrant alternative splicing events for the treatment of cancers and hereditary diseases, including gene therapy and redirecting splicing, using small molecules or splice switching oligonucleotides (SSO). Significant advances in the chemistry and pharmacology of nucleic acid have led to the development of clinically approved SSO drugs for the treatment of spinal muscular dystrophy and Duchenne muscular dystrophy (DMD). In this review, we discuss the mechanisms of SSO action with emphasis on "less common" approaches to modulate alternative splicing, including bipartite and bifunctional SSO, oligonucleotide decoys for splice factors and SSO-mediated mRNA degradation via AS-NMD and NGD pathways. We briefly discuss the current progress and future perspectives of SSO therapy for rare and ultrarare diseases.
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Affiliation(s)
- Olga V Sergeeva
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | | | - Noam Shomron
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Timofei S Zatsepin
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia.,Department of Chemistry, Moscow State University, Moscow, Russia
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28
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Raghavan V, Kraft L, Mesny F, Rigerte L. A simple guide to de novo transcriptome assembly and annotation. Brief Bioinform 2022; 23:6514404. [PMID: 35076693 PMCID: PMC8921630 DOI: 10.1093/bib/bbab563] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 12/03/2021] [Accepted: 12/09/2021] [Indexed: 12/13/2022] Open
Abstract
A transcriptome constructed from short-read RNA sequencing (RNA-seq) is an easily attainable proxy catalog of protein-coding genes when genome assembly is unnecessary, expensive or difficult. In the absence of a sequenced genome to guide the reconstruction process, the transcriptome must be assembled de novo using only the information available in the RNA-seq reads. Subsequently, the sequences must be annotated in order to identify sequence-intrinsic and evolutionary features in them (for example, protein-coding regions). Although straightforward at first glance, de novo transcriptome assembly and annotation can quickly prove to be challenging undertakings. In addition to familiarizing themselves with the conceptual and technical intricacies of the tasks at hand and the numerous pre- and post-processing steps involved, those interested must also grapple with an overwhelmingly large choice of tools. The lack of standardized workflows, fast pace of development of new tools and techniques and paucity of authoritative literature have served to exacerbate the difficulty of the task even further. Here, we present a comprehensive overview of de novo transcriptome assembly and annotation. We discuss the procedures involved, including pre- and post-processing steps, and present a compendium of corresponding tools.
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Affiliation(s)
- Venket Raghavan
- Corresponding authors: Venket Raghavan, Quantitative and Computational Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany. E-mail: ; Louis Kraft, Quantitative and Computational Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany. E-mail:
| | - Louis Kraft
- Corresponding authors: Venket Raghavan, Quantitative and Computational Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany. E-mail: ; Louis Kraft, Quantitative and Computational Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany. E-mail:
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29
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Cao X, Xu X, Dong J, Xue Y, Sun L, Zhu Y, Liu T, Jin Q. Genome-wide identification and functional analysis of circRNAs in Trichophyton rubrum conidial and mycelial stages. BMC Genomics 2022; 23:21. [PMID: 34983376 PMCID: PMC8725419 DOI: 10.1186/s12864-021-08184-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 11/18/2021] [Indexed: 12/28/2022] Open
Abstract
Background Circular RNAs (circRNAs) are a group of noncoding RNAs that participate in gene expression regulation in various pathways. The essential roles of circRNAs have been revealed in many species. However, knowledge of circRNAs in fungi is still not comprehensive. Results Trichophyton rubrum (T. rubrum) is considered a model organism of human pathogenic filamentous fungi and dermatophytes. In this study, we performed a genome-wide investigation of circRNAs in T. rubrum based on high-throughput sequencing and ultimately identified 4254 circRNAs. Most of these circRNAs were specific to the conidial or mycelial stage, revealing a developmental stage-specific expression pattern. In addition, 940 circRNAs were significantly differentially expressed between the conidial and mycelial stages. PCR experiments conducted on seven randomly selected differentially expressed (DE-) circRNAs confirmed the circularized structures and relative expression levels of these circRNAs. Based on their genome locations, most circRNAs originated from intergenic regions, unlike those in plants and animals. Furthermore, we constructed circRNA-miRNA-mRNA regulatory networks that included 661 DE-circRNAs targeting 140 miRNAs and further regulating 2753 mRNAs. The relative expression levels of two randomly selected circRNA-miRNA-mRNA axes were investigated by qRT-PCR, and the competing endogenous RNA (ceRNA) network theory was validated. Functional enrichment analysis of the target genes suggested that they were significantly involved in posttranscriptional processes and protein synthesis as well as some small-molecule metabolism processes. CircRNAs are relatively more conserved in closely related dermatophytes but rarely conserved in distantly related species. Tru_circ07138_001 is a highly conserved circRNA that was conserved in all ten dermatophytes analyzed in our study and three distantly related species. Its host gene TERG_07138 was also highly conserved in two of these distantly related species Gallus gallus and Caenorhabditis elegans. The specific role of this circRNA deserves further exploration. Conclusions Our study is the first to provide a global profile of circRNAs in T. rubrum as well as dermatophytes. These results could serve as valuable resources for research on circRNA regulatory mechanisms in fungi and reveal new insights for further investigation of the physical characteristics of these significant human fungal pathogens. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08184-y.
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Affiliation(s)
- Xingwei Cao
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Xingye Xu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Jie Dong
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Ying Xue
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Lilian Sun
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Yafang Zhu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Tao Liu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China.
| | - Qi Jin
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China.
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30
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Zhang P, Perez OC, Southey BR, Sweedler JV, Pradhan AA, Rodriguez-Zas SL. Alternative Splicing Mechanisms Underlying Opioid-Induced Hyperalgesia. Genes (Basel) 2021; 12:1570. [PMID: 34680965 PMCID: PMC8535871 DOI: 10.3390/genes12101570] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/19/2021] [Accepted: 09/30/2021] [Indexed: 12/13/2022] Open
Abstract
Prolonged use of opioids can cause opioid-induced hyperalgesia (OIH). The impact of alternative splicing on OIH remains partially characterized. A study of the absolute and relative modes of action of alternative splicing further the understanding of the molecular mechanisms underlying OIH. Differential absolute and relative isoform profiles were detected in the trigeminal ganglia and nucleus accumbens of mice presenting OIH behaviors elicited by chronic morphine administration relative to control mice. Genes that participate in glutamatergic synapse (e.g., Grip1, Grin1, Wnk3), myelin protein processes (e.g., Mbp, Mpz), and axon guidance presented absolute and relative splicing associated with OIH. Splicing of genes in the gonadotropin-releasing hormone receptor pathway was detected in the nucleus accumbens while splicing in the vascular endothelial growth factor, endogenous cannabinoid signaling, circadian clock system, and metabotropic glutamate receptor pathways was detected in the trigeminal ganglia. A notable finding was the prevalence of alternatively spliced transcription factors and regulators (e.g., Ciart, Ablim2, Pbx1, Arntl2) in the trigeminal ganglia. Insights into the nociceptive and antinociceptive modulatory action of Hnrnpk were gained. The results from our study highlight the impact of alternative splicing and transcriptional regulators on OIH and expose the need for isoform-level research to advance the understanding of morphine-associated hyperalgesia.
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Affiliation(s)
- Pan Zhang
- Illinois Informatics Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
| | - Olivia C. Perez
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (O.C.P.); (B.R.S.)
| | - Bruce R. Southey
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (O.C.P.); (B.R.S.)
| | - Jonathan V. Sweedler
- Department of Chemistry and the Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
| | - Amynah A. Pradhan
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612, USA;
| | - Sandra L. Rodriguez-Zas
- Illinois Informatics Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (O.C.P.); (B.R.S.)
- Department of Statistics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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31
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Kim JH, Jeong K, Li J, Murphy JM, Vukadin L, Stone JK, Richard A, Tran J, Gillespie GY, Flemington EK, Sobol RW, Lim STS, Ahn EYE. SON drives oncogenic RNA splicing in glioblastoma by regulating PTBP1/PTBP2 switching and RBFOX2 activity. Nat Commun 2021; 12:5551. [PMID: 34548489 PMCID: PMC8455679 DOI: 10.1038/s41467-021-25892-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 09/01/2021] [Indexed: 12/15/2022] Open
Abstract
While dysregulation of RNA splicing has been recognized as an emerging target for cancer therapy, the functional significance of RNA splicing and individual splicing factors in brain tumors is poorly understood. Here, we identify SON as a master regulator that activates PTBP1-mediated oncogenic splicing while suppressing RBFOX2-mediated non-oncogenic neuronal splicing in glioblastoma multiforme (GBM). SON is overexpressed in GBM patients and SON knockdown causes failure in intron removal from the PTBP1 transcript, resulting in PTBP1 downregulation and inhibition of its downstream oncogenic splicing. Furthermore, SON forms a complex with hnRNP A2B1 and antagonizes RBFOX2, which leads to skipping of RBFOX2-targeted cassette exons, including the PTBP2 neuronal exon. SON knockdown inhibits proliferation and clonogenicity of GBM cells in vitro and significantly suppresses tumor growth in orthotopic xenografts in vivo. Collectively, our study reveals that SON-mediated RNA splicing is a GBM vulnerability, implicating SON as a potential therapeutic target in brain tumors.
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Affiliation(s)
- Jung-Hyun Kim
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, USA
| | - Kyuho Jeong
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, USA
| | - Jianfeng Li
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, USA
| | - James M Murphy
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, USA
| | - Lana Vukadin
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joshua K Stone
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
| | - Alexander Richard
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
| | - Johnny Tran
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
| | - G Yancey Gillespie
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Erik K Flemington
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, USA
| | - Robert W Sobol
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA.
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, USA.
| | - Ssang-Teak Steve Lim
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, USA.
| | - Eun-Young Erin Ahn
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, AL, USA.
- O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA.
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32
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Saha K, Fernandez MM, Biswas T, Joseph S, Ghosh G. Discovery of a pre-mRNA structural scaffold as a contributor to the mammalian splicing code. Nucleic Acids Res 2021; 49:7103-7121. [PMID: 34161584 PMCID: PMC8266590 DOI: 10.1093/nar/gkab533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 06/03/2021] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
The specific recognition of splice signals at or near exon-intron junctions is not explained by their weak conservation and instead is postulated to require a multitude of features embedded in the pre-mRNA strand. We explored the possibility of 3D structural scaffold of AdML-a model pre-mRNA substrate-guiding early spliceosomal components to the splice signal sequences. We find that mutations in the non-cognate splice signal sequences impede recruitment of early spliceosomal components due to disruption of the global structure of the pre-mRNA. We further find that the pre-mRNA segments potentially interacting with the early spliceosomal component U1 snRNP are distributed across the intron, that there is a spatial proximity of 5' and 3' splice sites within the pre-mRNA scaffold, and that an interplay exists between the structural scaffold and splicing regulatory elements in recruiting early spliceosomal components. These results suggest that early spliceosomal components can recognize a 3D structural scaffold beyond the short splice signal sequences, and that in our model pre-mRNA, this scaffold is formed across the intron involving the major splice signals. This provides a conceptual basis to analyze the contribution of recognizable 3D structural scaffolds to the splicing code across the mammalian transcriptome.
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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
| | - Mike Minh Fernandez
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0375, USA
| | - Tapan Biswas
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0375, USA
| | - Simpson Joseph
- 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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Cao J, Xue Y. Characteristic chemical probing patterns of loop motifs improve prediction accuracy of RNA secondary structures. Nucleic Acids Res 2021; 49:4294-4307. [PMID: 33849076 PMCID: PMC8096282 DOI: 10.1093/nar/gkab250] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/24/2021] [Accepted: 04/10/2021] [Indexed: 12/14/2022] Open
Abstract
RNA structures play a fundamental role in nearly every aspect of cellular physiology and pathology. Gaining insights into the functions of RNA molecules requires accurate predictions of RNA secondary structures. However, the existing thermodynamic folding models remain less accurate than desired, even when chemical probing data, such as selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) reactivities, are used as restraints. Unlike most SHAPE-directed algorithms that only consider SHAPE restraints for base pairing, we extract two-dimensional structural features encoded in SHAPE data and establish robust relationships between characteristic SHAPE patterns and loop motifs of various types (hairpin, internal, and bulge) and lengths (2-11 nucleotides). Such characteristic SHAPE patterns are closely related to the sugar pucker conformations of loop residues. Based on these patterns, we propose a computational method, SHAPELoop, which refines the predicted results of the existing methods, thereby further improving their prediction accuracy. In addition, SHAPELoop can provide information about local or global structural rearrangements (including pseudoknots) and help researchers to easily test their hypothesized secondary structures.
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Affiliation(s)
- Jingyi Cao
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China
| | - Yi Xue
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China
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34
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Zhu J, Li C, Peng X, Zhang X. RNA architecture influences plant biology. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4144-4160. [PMID: 33484251 PMCID: PMC8130982 DOI: 10.1093/jxb/erab030] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/18/2021] [Indexed: 05/13/2023]
Abstract
The majority of the genome is transcribed to RNA in living organisms. RNA transcripts can form astonishing arrays of secondary and tertiary structures via Watson-Crick, Hoogsteen, or wobble base pairing. In vivo, RNA folding is not a simple thermodynamic event of minimizing free energy. Instead, the process is constrained by transcription, RNA-binding proteins, steric factors, and the microenvironment. RNA secondary structure (RSS) plays myriad roles in numerous biological processes, such as RNA processing, stability, transportation, and translation in prokaryotes and eukaryotes. Emerging evidence has also implicated RSS in RNA trafficking, liquid-liquid phase separation, and plant responses to environmental variations such as temperature and salinity. At molecular level, RSS is correlated with splicing, polyadenylation, protein synthesis, and miRNA biogenesis and functions. In this review, we summarize newly reported methods for probing RSS in vivo and functions and mechanisms of RSS in plant physiology.
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Affiliation(s)
- Jiaying Zhu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Changhao Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Xu Peng
- Department of Medical Physiology, College of Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Xiuren Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Correspondence:
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35
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Fish L, Khoroshkin M, Navickas A, Garcia K, Culbertson B, Hänisch B, Zhang S, Nguyen HCB, Soto LM, Dermit M, Mardakheh FK, Molina H, Alarcón C, Najafabadi HS, Goodarzi H. A prometastatic splicing program regulated by SNRPA1 interactions with structured RNA elements. Science 2021; 372:eabc7531. [PMID: 33986153 PMCID: PMC8238114 DOI: 10.1126/science.abc7531] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 04/01/2021] [Indexed: 12/14/2022]
Abstract
Aberrant alternative splicing is a hallmark of cancer, yet the underlying regulatory programs that control this process remain largely unknown. Here, we report a systematic effort to decipher the RNA structural code that shapes pathological splicing during breast cancer metastasis. We discovered a previously unknown structural splicing enhancer that is enriched near cassette exons with increased inclusion in highly metastatic cells. We show that the spliceosomal protein small nuclear ribonucleoprotein polypeptide A' (SNRPA1) interacts with these enhancers to promote cassette exon inclusion. This interaction enhances metastatic lung colonization and cancer cell invasion, in part through SNRPA1-mediated regulation of PLEC alternative splicing, which can be counteracted by splicing modulating morpholinos. Our findings establish a noncanonical regulatory role for SNRPA1 as a prometastatic splicing enhancer in breast cancer.
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Affiliation(s)
- Lisa Fish
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA 94158, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Matvei Khoroshkin
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA 94158, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Albertas Navickas
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA 94158, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Kristle Garcia
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA 94158, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Bruce Culbertson
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA 94158, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Benjamin Hänisch
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA 94158, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Steven Zhang
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA 94158, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hoang C B Nguyen
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Larisa M Soto
- Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada
- McGill Genome Centre, Montreal, QC H3A 0G1, Canada
| | - Maria Dermit
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Faraz K Mardakheh
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Henrik Molina
- Proteome Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - Claudio Alarcón
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
- Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Hamed S Najafabadi
- Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada
- McGill Genome Centre, Montreal, QC H3A 0G1, Canada
| | - Hani Goodarzi
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
- Department of Urology, University of California, San Francisco, San Francisco, CA 94158, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
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36
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Conboy JG. Unannotated splicing regulatory elements in deep intron space. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1656. [PMID: 33887804 DOI: 10.1002/wrna.1656] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/14/2021] [Accepted: 03/23/2021] [Indexed: 12/21/2022]
Abstract
Deep intron space harbors a diverse array of splicing regulatory elements that cooperate with better-known exon-proximal elements to enforce proper tissue-specific and development-specific pre-mRNA processing. Many deep intron elements have been highly conserved through vertebrate evolution, yet remain poorly annotated in the human genome. Recursive splicing exons (RS-exons) and intraexons promote noncanonical, multistep resplicing pathways in long introns, involving transient intermediate structures that are greatly underrepresented in RNA-seq datasets. Decoy splice sites and decoy exons act at a distance to inhibit splicing catalysis at annotated splice sites, with functional consequences such as exon skipping and intron retention. RNA:RNA bridges can juxtapose distant sequences within or across introns to activate deep intron splicing enhancers and silencers, to loop out exons to be skipped, or to select one member of a mutually exclusive set of exons. Similarly, protein bridges mediated by interactions among transcript-bound RNA binding proteins (RBPs) can modulate splicing outcomes. Experimental disruption of deep intron elements serving any of these functions can abrogate normal splicing, strongly suggesting that natural mutations of deep intron elements can do likewise to cause human disease. Understanding noncanonical splicing pathways and discovering deep intron regulatory signals, many of which map hundreds to many thousands of nucleotides from annotated splice junctions, is of great academic interest for basic scientists studying alternative splicing mechanisms. Hopefully, this knowledge coupled with increased analysis of deep intron sequences will also have important medical applications, as better interpretation of deep intron mutations may reveal new disease mechanisms and suggest new therapies. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- John G Conboy
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, California, USA
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37
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Conserved long-range base pairings are associated with pre-mRNA processing of human genes. Nat Commun 2021; 12:2300. [PMID: 33863890 PMCID: PMC8052449 DOI: 10.1038/s41467-021-22549-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 03/20/2021] [Indexed: 02/07/2023] Open
Abstract
The ability of nucleic acids to form double-stranded structures is essential for all living systems on Earth. Current knowledge on functional RNA structures is focused on locally-occurring base pairs. However, crosslinking and proximity ligation experiments demonstrated that long-range RNA structures are highly abundant. Here, we present the most complete to-date catalog of conserved complementary regions (PCCRs) in human protein-coding genes. PCCRs tend to occur within introns, suppress intervening exons, and obstruct cryptic and inactive splice sites. Double-stranded structure of PCCRs is supported by decreased icSHAPE nucleotide accessibility, high abundance of RNA editing sites, and frequent occurrence of forked eCLIP peaks. Introns with PCCRs show a distinct splicing pattern in response to RNAPII slowdown suggesting that splicing is widely affected by co-transcriptional RNA folding. The enrichment of 3'-ends within PCCRs raises the intriguing hypothesis that coupling between RNA folding and splicing could mediate co-transcriptional suppression of premature pre-mRNA cleavage and polyadenylation.
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38
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Gadgil A, Raczyńska KD. U7 snRNA: A tool for gene therapy. J Gene Med 2021; 23:e3321. [PMID: 33590603 PMCID: PMC8243935 DOI: 10.1002/jgm.3321] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 01/22/2021] [Accepted: 02/09/2021] [Indexed: 12/25/2022] Open
Abstract
Most U-rich small nuclear ribonucleoproteins (snRNPs) are complexes that mediate the splicing of pre-mRNAs. U7 snRNP is an exception in that it is not involved in splicing but is a key factor in the unique 3' end processing of replication-dependent histone mRNAs. However, by introducing controlled changes in the U7 snRNA histone binding sequence and in the Sm motif, it can be used as an effective tool for gene therapy. The modified U7 snRNP (U7 Sm OPT) is thus not involved in the processing of replication-dependent histone pre-mRNA but targets splicing by inducing efficient skipping or inclusion of selected exons. U7 Sm OPT is of therapeutic importance in diseases that are an outcome of splicing defects, such as myotonic dystrophy, Duchenne muscular dystrophy, amyotrophic lateral sclerosis, β-thalassemia, HIV-1 infection and spinal muscular atrophy. The benefits of using U7 Sm OPT for gene therapy are its compact size, ability to accumulate in the nucleus without causing any toxic effects in the cells, and no immunoreactivity. The risk of transgene misregulation by using U7 Sm OPT is also low because it is involved in correcting the expression of an endogenous gene controlled by its own regulatory elements. Altogether, using U7 Sm OPT as a tool in gene therapy can ensure lifelong treatment, whereas an oligonucleotide or other drug/compound would require repeated administration. It would thus be strategic to harness these unique properties of U7 snRNP and deploy it as a tool in gene therapy.
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Affiliation(s)
- Ankur Gadgil
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of BiologyAdam Mickiewicz UniversityPoznanPoland
- Center for Advanced TechnologyAdam Mickiewicz UniversityPoznanPoland
| | - Katarzyna Dorota Raczyńska
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of BiologyAdam Mickiewicz UniversityPoznanPoland
- Center for Advanced TechnologyAdam Mickiewicz UniversityPoznanPoland
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39
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Schärfen L, Neugebauer KM. Transcription Regulation Through Nascent RNA Folding. J Mol Biol 2021; 433:166975. [PMID: 33811916 DOI: 10.1016/j.jmb.2021.166975] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/14/2022]
Abstract
Folding of RNA into secondary structures through intramolecular base pairing determines an RNA's three-dimensional architecture and associated function. Simple RNA structures like stem loops can provide specialized functions independent of coding capacity, such as protein binding, regulation of RNA processing and stability, stimulation or inhibition of translation. RNA catalysis is dependent on tertiary structures found in the ribosome, tRNAs and group I and II introns. While the extent to which non-coding RNAs contribute to cellular maintenance is generally appreciated, the fact that both non-coding and coding RNA can assume relevant structural states has only recently gained attention. In particular, the co-transcriptional folding of nascent RNA of all classes has the potential to regulate co-transcriptional processing, RNP (ribonucleoprotein particle) formation, and transcription itself. Riboswitches are established examples of co-transcriptionally folded coding RNAs that directly regulate transcription, mainly in prokaryotes. Here we discuss recent studies in both prokaryotes and eukaryotes showing that structure formation may carry a more widespread regulatory logic during RNA synthesis. Local structures forming close to the catalytic center of RNA polymerases have the potential to regulate transcription by reducing backtracking. In addition, stem loops or more complex structures may alter co-transcriptional RNA processing or its efficiency. Several examples of functional structures have been identified to date, and this review provides an overview of physiologically distinct processes where co-transcriptionally folded RNA plays a role. Experimental approaches such as single-molecule FRET and in vivo structural probing to further advance our insight into the significance of co-transcriptional structure formation are discussed.
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Affiliation(s)
- Leonard Schärfen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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40
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Saldi T, Riemondy K, Erickson B, Bentley DL. Alternative RNA structures formed during transcription depend on elongation rate and modify RNA processing. Mol Cell 2021; 81:1789-1801.e5. [PMID: 33631106 DOI: 10.1016/j.molcel.2021.01.040] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 12/24/2022]
Abstract
Most RNA processing occurs co-transcriptionally. We interrogated nascent pol II transcripts by chemical and enzymatic probing and determined how the "nascent RNA structureome" relates to splicing, A-I editing and transcription speed. RNA folding within introns and steep structural transitions at splice sites are associated with efficient co-transcriptional splicing. A slow pol II mutant elicits extensive remodeling into more folded conformations with increased A-I editing. Introns that become more structured at their 3' splice sites get co-transcriptionally excised more efficiently. Slow pol II altered folding of intronic Alu elements where cryptic splicing and intron retention are stimulated, an outcome mimicked by UV, which decelerates transcription. Slow transcription also remodeled RNA folding around alternative exons in distinct ways that predict whether skipping or inclusion is favored, even though it occurs post-transcriptionally. Hence, co-transcriptional RNA folding modulates post-transcriptional alternative splicing. In summary, the plasticity of nascent transcripts has widespread effects on RNA processing.
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Affiliation(s)
- Tassa Saldi
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - Kent Riemondy
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - Benjamin Erickson
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - David L Bentley
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA.
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41
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Bitaraf A, Razmara E, Bakhshinejad B, Yousefi H, Vatanmakanian M, Garshasbi M, Cho WC, Babashah S. The oncogenic and tumor suppressive roles of RNA-binding proteins in human cancers. J Cell Physiol 2021; 236:6200-6224. [PMID: 33559213 DOI: 10.1002/jcp.30311] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 01/14/2021] [Accepted: 01/22/2021] [Indexed: 12/17/2022]
Abstract
Posttranscriptional regulation is a mechanism for the cells to control gene regulation at the RNA level. In this process, RNA-binding proteins (RBPs) play central roles and orchestrate the function of RNA molecules in multiple steps. Accumulating evidence has shown that the aberrant regulation of RBPs makes contributions to the initiation and progression of tumorigenesis via numerous mechanisms such as genetic changes, epigenetic alterations, and noncoding RNA-mediated regulations. In this article, we review the effects caused by RBPs and their functional diversity in the malignant transformation of cancer cells that occurs through the involvement of these proteins in various stages of RNA regulation including alternative splicing, stability, polyadenylation, localization, and translation. Besides this, we review the various interactions between RBPs and other crucial posttranscriptional regulators such as microRNAs and long noncoding RNAs in the pathogenesis of cancer. Finally, we discuss the potential approaches for targeting RBPs in human cancers.
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Affiliation(s)
- Amirreza Bitaraf
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ehsan Razmara
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Babak Bakhshinejad
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Hassan Yousefi
- Department of Biochemistry and Molecular Biology, LSUHSC School of Medicine, New Orleans, Louisiana, USA
| | - Mousa Vatanmakanian
- Department of Biochemistry and Molecular Biology, LSUHSC School of Medicine, New Orleans, Louisiana, USA
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - William C Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Kowloon, Hong Kong
| | - Sadegh Babashah
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
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42
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Kück U, Schmitt O. The Chloroplast Trans-Splicing RNA-Protein Supercomplex from the Green Alga Chlamydomonas reinhardtii. Cells 2021; 10:cells10020290. [PMID: 33535503 PMCID: PMC7912774 DOI: 10.3390/cells10020290] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/27/2022] Open
Abstract
In eukaryotes, RNA trans-splicing is a significant RNA modification process for the end-to-end ligation of exons from separately transcribed primary transcripts to generate mature mRNA. So far, three different categories of RNA trans-splicing have been found in organisms within a diverse range. Here, we review trans-splicing of discontinuous group II introns, which occurs in chloroplasts and mitochondria of lower eukaryotes and plants. We discuss the origin of intronic sequences and the evolutionary relationship between chloroplast ribonucleoprotein complexes and the nuclear spliceosome. Finally, we focus on the ribonucleoprotein supercomplex involved in trans-splicing of chloroplast group II introns from the green alga Chlamydomonas reinhardtii. This complex has been well characterized genetically and biochemically, resulting in a detailed picture of the chloroplast ribonucleoprotein supercomplex. This information contributes substantially to our understanding of the function of RNA-processing machineries and might provide a blueprint for other splicing complexes involved in trans- as well as cis-splicing of organellar intron RNAs.
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43
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Hoser SM, Hoffmann A, Meindl A, Gamper M, Fallmann J, Bernhart SH, Müller L, Ploner M, Misslinger M, Kremser L, Lindner H, Geley S, Schaal H, Stadler PF, Huettenhofer A. Intronic tRNAs of mitochondrial origin regulate constitutive and alternative splicing. Genome Biol 2020; 21:299. [PMID: 33292386 PMCID: PMC7722341 DOI: 10.1186/s13059-020-02199-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 11/09/2020] [Indexed: 02/19/2023] Open
Abstract
BACKGROUND The presence of nuclear mitochondrial DNA (numtDNA) has been reported within several nuclear genomes. Next to mitochondrial protein-coding genes, numtDNA sequences also encode for mitochondrial tRNA genes. However, the biological roles of numtDNA remain elusive. RESULTS Employing in silico analysis, we identify 281 mitochondrial tRNA homologs in the human genome, which we term nimtRNAs (nuclear intronic mitochondrial-derived tRNAs), being contained within introns of 76 nuclear host genes. Despite base changes in nimtRNAs when compared to their mtRNA homologs, a canonical tRNA cloverleaf structure is maintained. To address potential functions of intronic nimtRNAs, we insert them into introns of constitutive and alternative splicing reporters and demonstrate that nimtRNAs promote pre-mRNA splicing, dependent on the number and positioning of nimtRNA genes and splice site recognition efficiency. A mutational analysis reveals that the nimtRNA cloverleaf structure is required for the observed splicing increase. Utilizing a CRISPR/Cas9 approach, we show that a partial deletion of a single endogenous nimtRNALys within intron 28 of the PPFIBP1 gene decreases inclusion of the downstream-located exon 29 of the PPFIBP1 mRNA. By employing a pull-down approach followed by mass spectrometry, a 3'-splice site-associated protein network is identified, including KHDRBS1, which we show directly interacts with nimtRNATyr by an electrophoretic mobility shift assay. CONCLUSIONS We propose that nimtRNAs, along with associated protein factors, can act as a novel class of intronic splicing regulatory elements in the human genome by participating in the regulation of splicing.
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Affiliation(s)
- Simon M Hoser
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria.
| | - Anne Hoffmann
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Philipp-Rosenthal-Str. 27, 04103, Leipzig, Germany
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107, Leipzig, Germany
| | - Andreas Meindl
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Maximilian Gamper
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Jörg Fallmann
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107, Leipzig, Germany
| | - Stephan H Bernhart
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107, Leipzig, Germany
| | - Lisa Müller
- Institute for Virology, Medical Faculty Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Melanie Ploner
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Matthias Misslinger
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Leopold Kremser
- Division of Clinical Biochemistry, Protein Micro-Analysis Facility, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Herbert Lindner
- Division of Clinical Biochemistry, Protein Micro-Analysis Facility, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Stephan Geley
- Institute of Pathophysiology, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Heiner Schaal
- Institute for Virology, Medical Faculty Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Peter F Stadler
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107, Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, Inselstraße 22, 04103, Leipzig, Germany
| | - Alexander Huettenhofer
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria.
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44
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Shenasa H, Movassat M, Forouzmand E, Hertel KJ. Allosteric regulation of U1 snRNP by splicing regulatory proteins controls spliceosomal assembly. RNA (NEW YORK, N.Y.) 2020; 26:1389-1399. [PMID: 32522889 PMCID: PMC7491332 DOI: 10.1261/rna.075135.120] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/02/2020] [Indexed: 06/01/2023]
Abstract
Alternative splicing is responsible for much of the transcriptomic and proteomic diversity observed in eukaryotes and involves combinatorial regulation by many cis-acting elements and trans-acting factors. SR and hnRNP splicing regulatory proteins often have opposing effects on splicing efficiency depending on where they bind the pre-mRNA relative to the splice site. Position-dependent splicing repression occurs at spliceosomal E-complex, suggesting that U1 snRNP binds but cannot facilitate higher order spliceosomal assembly. To test the hypothesis that the structure of U1 snRNA changes during activation or repression, we developed a method to structure-probe native U1 snRNP in enriched conformations that mimic activated or repressed spliceosomal E-complexes. While the core of U1 snRNA is highly structured, the 5' end of U1 snRNA shows different SHAPE reactivities and psoralen crosslinking efficiencies depending on where splicing regulatory elements are located relative to the 5' splice site. A motif within the 5' splice site binding region of U1 snRNA is more reactive toward SHAPE electrophiles when repressors are bound, suggesting U1 snRNA is bound, but less base-paired. These observations demonstrate that splicing regulators modulate splice site selection allosterically.
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Affiliation(s)
- Hossein Shenasa
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California 92697, USA
| | - Maliheh Movassat
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California 92697, USA
| | - Elmira Forouzmand
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California 92697, USA
| | - Klemens J Hertel
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California 92697, USA
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45
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Li X, Zhang B, Li F, Yu K, Bai Y. The mechanism and detection of alternative splicing events in circular RNAs. PeerJ 2020; 8:e10032. [PMID: 33033662 PMCID: PMC7521338 DOI: 10.7717/peerj.10032] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/03/2020] [Indexed: 01/15/2023] Open
Abstract
Circular RNAs (circRNAs) are considered as functional biomolecules with tissue/development-specific expression patterns. Generally, a single gene may generate multiple circRNA variants by alternative splicing, which contain different combinations of exons and/or introns. Due to the low abundance of circRNAs as well as overlapped with their linear counterparts, circRNA enrichment protocol is needed prior to sequencing. Compared with numerous algorithms, which use back-splicing reads for detection and functional characterization of circRNAs, original bioinformatic analyzing tools have been developed to large-scale determination of full-length circRNAs and accurate quantification. This review provides insights into the complexity of circRNA biogenesis and surveys the recent progresses in the experimental and bioinformatic methodologies that focus on accurately full-length circRNAs identification.
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Affiliation(s)
- Xiaohan Li
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Bing Zhang
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Fuyu Li
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Kequan Yu
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Yunfei Bai
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
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Jakubauskienė E, Vilys L, Pečiulienė I, Kanopka A. The role of hypoxia on Alzheimer's disease-related APP and Tau mRNA formation. Gene 2020; 766:145146. [PMID: 32941952 DOI: 10.1016/j.gene.2020.145146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 08/24/2020] [Accepted: 09/09/2020] [Indexed: 12/26/2022]
Abstract
The removal of introns from mRNA precursors (pre-mRNAs) is an essential step in eukaryotic gene expression. The splicing machinery heavily contributes to biological complexity and especially to the ability of cells to adapt to altered cellular conditions. Hypoxia also plays a key role in the pathophysiology of many diseases, including Alzheimer's disease (AD). In the presented study, we have examined the influence of cellular hypoxia on mRNA splice variant formation from Alzheimer's disease-related Tau and APP genes in brain cells. We have shown that the hypoxic microenvironment influenced the formation of Tau mRNA splice variants, but had no effect on APP mRNA splice variant formation. Additionally, our presented results indicate that splicing factor SRSF1 but not SRSF5 alters the formation of Tau cellular mRNA splice variants in hypoxic cells. Obtained results have also shown that hypoxic brain cells possess enhanced CLK1-4 kinase mRNA levels. This study underlines that cellular hypoxia can influence disease development through changing pre-mRNA splicing.
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Affiliation(s)
| | - Laurynas Vilys
- Institute of Biotechnology, Vilnius University, Vilnius, Lithuania
| | - Inga Pečiulienė
- Institute of Biotechnology, Vilnius University, Vilnius, Lithuania
| | - Arvydas Kanopka
- Institute of Biotechnology, Vilnius University, Vilnius, Lithuania.
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47
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Xu B, Meng Y, Jin Y. RNA structures in alternative splicing and back-splicing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1626. [PMID: 32929887 DOI: 10.1002/wrna.1626] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/14/2020] [Accepted: 08/22/2020] [Indexed: 12/12/2022]
Abstract
Alternative splicing greatly expands the transcriptomic and proteomic diversities related to physiological and developmental processes in higher eukaryotes. Splicing of long noncoding RNAs, and back- and trans- splicing further expanded the regulatory repertoire of alternative splicing. RNA structures were shown to play an important role in regulating alternative splicing and back-splicing. Application of novel sequencing technologies made it possible to identify genome-wide RNA structures and interaction networks, which might provide new insights into RNA splicing regulation in vitro to in vivo. The emerging transcription-folding-splicing paradigm is changing our understanding of RNA alternative splicing regulation. Here, we review the insights into the roles and mechanisms of RNA structures in alternative splicing and back-splicing, as well as how disruption of these structures affects alternative splicing and then leads to human diseases. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
| | - Yijun Meng
- College of Life and Environmental Sciences, Hangzhou Normal University, Zhejiang, Hangzhou, China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
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Maris C, Jayne S, Damberger FF, Beusch I, Dorn G, Ravindranathan S, Allain FHT. A transient α-helix in the N-terminal RNA recognition motif of polypyrimidine tract binding protein senses RNA secondary structure. Nucleic Acids Res 2020; 48:4521-4537. [PMID: 32170319 PMCID: PMC7192611 DOI: 10.1093/nar/gkaa155] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/22/2020] [Accepted: 03/04/2020] [Indexed: 12/14/2022] Open
Abstract
The polypyrimidine tract binding protein (PTB) is a multi-domain protein involved in alternative splicing, mRNA localization, stabilization, polyadenylation and translation initiation from internal ribosome entry sites (IRES). In this latter process, PTB promotes viral translation by interacting extensively with complex structured regions in the 5′-untranslated regions of viral RNAs at pyrimidine-rich targets located in single strand and hairpin regions. To better understand how PTB recognizes structured elements in RNA targets, we solved the solution structure of the N-terminal RNA recognition motif (RRM) in complex with an RNA hairpin embedding the loop sequence UCUUU, which is frequently found in IRESs of the picornovirus family. Surprisingly, a new three-turn α3 helix C-terminal to the RRM, folds upon binding the RNA hairpin. Although α3 does not mediate any contacts to the RNA, it acts as a sensor of RNA secondary structure, suggesting a role for RRM1 in detecting pyrimidine tracts in the context of structured RNA. Moreover, the degree of helix formation depends on the RNA loop sequence. Finally, we show that the α3 helix region, which is highly conserved in vertebrates, is crucial for PTB function in enhancing Encephalomyocarditis virus IRES activity.
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Affiliation(s)
| | - Sandrine Jayne
- Department of Biology, ETH Zurich, 8093 Zürich, Switzerland
| | | | - Irene Beusch
- Department of Biology, ETH Zurich, 8093 Zürich, Switzerland
| | - Georg Dorn
- Department of Biology, ETH Zurich, 8093 Zürich, Switzerland
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Serey-Gaut M, Scala M, Reversade B, Ruaud L, Cabrol C, Musacchia F, Torella A, Accogli A, Escande-Beillard N, Langlais J, Piatelli G, Consales A, Nigro V, Capra V, Van Maldergem L. Congenital posterior cervical spine malformation due to biallelic c.240-4T>G RIPPLY2 variant: A discrete entity. Am J Med Genet A 2020; 182:1466-1472. [PMID: 32212228 DOI: 10.1002/ajmg.a.61549] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 01/25/2023]
Abstract
The clinical and radiological spectrum of spondylocostal dysostosis syndromes encompasses distinctive costo-vertebral anomalies. RIPPLY2 biallelic pathogenic variants were described in two distinct cervical spine malformation syndromes: Klippel-Feil syndrome and posterior cervical spine malformation. RIPPLY2 is involved in the determination of rostro-caudal polarity and somite patterning during development. To date, only four cases have been reported. The current report aims at further delineating the posterior malformation in three new patients. Three patients from two unrelated families underwent clinical and radiological examination through X-ray, 3D computed tomography and brain magnetic resonance imaging. After informed consent was obtained, family-based whole exome sequencing (WES) was performed. Complex vertebral segmentation defects in the cervico-thoracic spine were observed in all patients. WES led to the identification of the homozygous splicing variant c.240-4T>G in all subjects. This variant is predicted to result in aberrant splicing of Exon 4. The current report highlights a subtype of cervical spine malformation with major atlo-axoidal malformation compromising spinal cord integrity. This distinctive mutation-specific pattern of malformation differs from Klippel-Feil syndrome and broadens the current classification, defining a sub-type of RIPPLY2-related skeletal disorder. Of note, the phenotype of one patient overlaps with oculo-auriculo-vertebral spectrum disorder.
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Affiliation(s)
- Margaux Serey-Gaut
- Centre de génétique humaine, Université de Franche Comté, Besançon, France
| | - Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.,Department of Neurosurgery, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Bruno Reversade
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore.,Laboratory of Human Embryology and Genetics, Institute of Medical Biology, A*STAR, Singapore, Singapore.,Medical Genetics Department, Koç University School of Medicine, Istanbul, Turkey
| | - Lyse Ruaud
- Université de Paris, Paris, France.,Service de génétique clinique, AP-HP, Hôpital Robert Debré, Paris, France
| | - Christelle Cabrol
- Centre de génétique humaine, Université de Franche Comté, Besançon, France
| | | | - Annalaura Torella
- Telethon Institute of Genetics and Medicine, Naples, Italy.,Department of Precision Medicine, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Andrea Accogli
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.,Department of Neurosurgery, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Nathalie Escande-Beillard
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore.,Medical Genetics Department, Koç University School of Medicine, Istanbul, Turkey
| | - Jean Langlais
- Department of Pediatric Orthopedic Surgery, University Hospital, Université de Franche Comté, Besançon, France
| | - Gianluca Piatelli
- Department of Neurosurgery, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | | | - Vincenzo Nigro
- Telethon Institute of Genetics and Medicine, Naples, Italy.,Department of Precision Medicine, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Valeria Capra
- Department of Neurosurgery, IRCCS Istituto Giannina Gaslini, Genoa, Italy
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50
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Lasham A, Tsai P, Fitzgerald SJ, Mehta SY, Knowlton NS, Braithwaite AW, Print CG. Accessing a New Dimension in TP53 Biology: Multiplex Long Amplicon Digital PCR to Specifically Detect and Quantitate Individual TP53 Transcripts. Cancers (Basel) 2020; 12:cancers12030769. [PMID: 32213968 PMCID: PMC7140069 DOI: 10.3390/cancers12030769] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 12/21/2022] Open
Abstract
TP53, the most commonly-mutated gene in cancer, undergoes complex alternative splicing. Different TP53 transcripts play different biological roles, both in normal function and in the progression of diseases such as cancer. The study of TP53’s alternative RNA splice forms and their use as clinical biomarkers has been hampered by limited specificity and quantitative accuracy of current methods. TP53 RNA splice variants differ at both 5’ and 3’ ends, but because they have a common central region of 618 bp, the individual TP53 transcripts are impossible to specifically detect and precisely quantitate using standard PCR-based methods or short-read RNA sequencing. Therefore, we devised multiplex probe-based long amplicon droplet digital PCR (ddPCR) assays, which for the first time allow precise end-to-end quantitation of the seven major TP53 transcripts, with amplicons ranging from 0.85 to 1.85 kb. Multiple modifications to standard ddPCR assay procedures were required to enable specific co-amplification of these long transcripts and to overcome issues with secondary structure. Using these assays, we show that several TP53 transcripts are co-expressed in breast cancers, and illustrate the potential for this method to identify novel TP53 transcripts in tumour cells. This capability will facilitate a new level of biological and clinical understanding of the alternatively-spliced TP53 isoforms.
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Affiliation(s)
- Annette Lasham
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland 1142, New Zealand; (P.T.); (S.J.F.); (N.S.K.); (C.G.P.)
- Maurice Wilkins Centre, University of Auckland, Auckland 1010, New Zealand; (S.Y.M.); (A.W.B.)
- Correspondence:
| | - Peter Tsai
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland 1142, New Zealand; (P.T.); (S.J.F.); (N.S.K.); (C.G.P.)
- Maurice Wilkins Centre, University of Auckland, Auckland 1010, New Zealand; (S.Y.M.); (A.W.B.)
| | - Sandra J. Fitzgerald
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland 1142, New Zealand; (P.T.); (S.J.F.); (N.S.K.); (C.G.P.)
- Maurice Wilkins Centre, University of Auckland, Auckland 1010, New Zealand; (S.Y.M.); (A.W.B.)
| | - Sunali Y. Mehta
- Maurice Wilkins Centre, University of Auckland, Auckland 1010, New Zealand; (S.Y.M.); (A.W.B.)
- Department of Pathology, University of Otago, Dunedin 9016, New Zealand
| | - Nicholas S. Knowlton
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland 1142, New Zealand; (P.T.); (S.J.F.); (N.S.K.); (C.G.P.)
- Maurice Wilkins Centre, University of Auckland, Auckland 1010, New Zealand; (S.Y.M.); (A.W.B.)
| | - Antony W. Braithwaite
- Maurice Wilkins Centre, University of Auckland, Auckland 1010, New Zealand; (S.Y.M.); (A.W.B.)
- Department of Pathology, University of Otago, Dunedin 9016, New Zealand
- Malaghan Institute of Medical Research, Wellington 6242, New Zealand
| | - Cristin G. Print
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland 1142, New Zealand; (P.T.); (S.J.F.); (N.S.K.); (C.G.P.)
- Maurice Wilkins Centre, University of Auckland, Auckland 1010, New Zealand; (S.Y.M.); (A.W.B.)
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