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Xu WB, Zhao L, Liu P, Guo QH, Wu CA, Yang GD, Huang JG, Zhang SX, Guo XQ, Zhang SZ, Zheng CC, Yan K. Intronic microRNA-directed regulation of mitochondrial reactive oxygen species enhances plant stress tolerance in Arabidopsis. THE NEW PHYTOLOGIST 2023; 240:710-726. [PMID: 37547968 DOI: 10.1111/nph.19168] [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: 04/05/2023] [Accepted: 07/05/2023] [Indexed: 08/08/2023]
Abstract
MicroRNAs (miRNAs) play crucial roles in regulating plant development and stress responses. However, the functions and mechanism of intronic miRNAs in plants are poorly understood. This study reports a stress-responsive RNA splicing mechanism for intronic miR400 production, whereby miR400 modulates reactive oxygen species (ROS) accumulation and improves plant tolerance by downregulating its target expression. To monitor the intron splicing events, we used an intronic miR400 splicing-dependent luciferase transgenic line. Luciferase activity was observed to decrease after high cadmium concentration treatment due to the retention of the miR400-containing intron, which inhibited the production of mature miR400. Furthermore, we demonstrated that under Cd treatments, Pentatricopeptide Repeat Protein 1 (PPR1), the target of miR400, acts as a positive regulator by inducing ROS accumulation. Ppr1 mutation affected the Complex III activity in the electron transport chain and RNA editing of the mitochondrial gene ccmB. This study illustrates intron splicing as a key step in intronic miR400 production and highlights the function of intronic miRNAs as a 'signal transducer' in enhancing plant stress tolerance.
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Affiliation(s)
- Wei-Bo Xu
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Lei Zhao
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Peng Liu
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - Qian-Huan Guo
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Chang-Ai Wu
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Guo-Dong Yang
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Jin-Guang Huang
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Shu-Xin Zhang
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Xing-Qi Guo
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Shi-Zhong Zhang
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Cheng-Chao Zheng
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Kang Yan
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China
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Gonçalves M, Santos JI, Coutinho MF, Matos L, Alves S. Development of Engineered-U1 snRNA Therapies: Current Status. Int J Mol Sci 2023; 24:14617. [PMID: 37834063 PMCID: PMC10572768 DOI: 10.3390/ijms241914617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023] Open
Abstract
Splicing of pre-mRNA is a crucial regulatory stage in the pathway of gene expression. The majority of human genes that encode proteins undergo alternative pre-mRNA splicing and mutations that affect splicing are more prevalent than previously thought. Targeting aberrant RNA(s) may thus provide an opportunity to correct faulty splicing and potentially treat numerous genetic disorders. To that purpose, the use of engineered U1 snRNA (either modified U1 snRNAs or exon-specific U1s-ExSpeU1s) has been applied as a potentially therapeutic strategy to correct splicing mutations, particularly those affecting the 5' splice-site (5'ss). Here we review and summarize a vast panoply of studies that used either modified U1 snRNAs or ExSpeU1s to mediate gene therapeutic correction of splicing defects underlying a considerable number of genetic diseases. We also focus on the pre-clinical validation of these therapeutic approaches both in vitro and in vivo, and summarize the main obstacles that need to be overcome to allow for their successful translation to clinic practice in the future.
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Affiliation(s)
- Mariana Gonçalves
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, CITAB, Inov4Agro, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal
| | - Juliana Inês Santos
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Maria Francisca Coutinho
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Liliana Matos
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Sandra Alves
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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Ottesen EW, Singh NN, Luo D, Kaas B, Gillette B, Seo J, Jorgensen H, Singh RN. Diverse targets of SMN2-directed splicing-modulating small molecule therapeutics for spinal muscular atrophy. Nucleic Acids Res 2023; 51:5948-5980. [PMID: 37026480 PMCID: PMC10325915 DOI: 10.1093/nar/gkad259] [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: 09/07/2021] [Revised: 03/13/2023] [Accepted: 03/28/2023] [Indexed: 04/08/2023] Open
Abstract
Designing an RNA-interacting molecule that displays high therapeutic efficacy while retaining specificity within a broad concentration range remains a challenging task. Risdiplam is an FDA-approved small molecule for the treatment of spinal muscular atrophy (SMA), the leading genetic cause of infant mortality. Branaplam is another small molecule which has undergone clinical trials. The therapeutic merit of both compounds is based on their ability to restore body-wide inclusion of Survival Motor Neuron 2 (SMN2) exon 7 upon oral administration. Here we compare the transcriptome-wide off-target effects of these compounds in SMA patient cells. We captured concentration-dependent compound-specific changes, including aberrant expression of genes associated with DNA replication, cell cycle, RNA metabolism, cell signaling and metabolic pathways. Both compounds triggered massive perturbations of splicing events, inducing off-target exon inclusion, exon skipping, intron retention, intron removal and alternative splice site usage. Our results of minigenes expressed in HeLa cells provide mechanistic insights into how these molecules targeted towards a single gene produce different off-target effects. We show the advantages of combined treatments with low doses of risdiplam and branaplam. Our findings are instructive for devising better dosing regimens as well as for developing the next generation of small molecule therapeutics aimed at splicing modulation.
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Affiliation(s)
- Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Diou Luo
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Bailey Kaas
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Benjamin J Gillette
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Joonbae Seo
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Hannah J Jorgensen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
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Lazo PA, Morejón-García P. VRK1 variants at the cross road of Cajal body neuropathogenic mechanisms in distal neuropathies and motor neuron diseases. Neurobiol Dis 2023; 183:106172. [PMID: 37257665 DOI: 10.1016/j.nbd.2023.106172] [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: 03/24/2023] [Revised: 05/09/2023] [Accepted: 05/24/2023] [Indexed: 06/02/2023] Open
Abstract
Distal hereditary neuropathies and neuro motor diseases are complex neurological phenotypes associated with pathogenic variants in a large number of genes, but in some the origin is unknown. Recently, rare pathogenic variants of the human VRK1 gene have been associated with these neurological phenotypes. All VRK1 pathogenic variants are recessive, and their clinical presentation occurs in either homozygous or compound heterozygous patients. The pathogenic VRK1 gene pathogenic variants are located in three clusters within the protein sequence. The main, and initial, shared clinical phenotype among VRK1 pathogenic variants is a distal progressive loss of motor and/or sensory function, which includes diseases such as spinal muscular atrophy, Charcot-Marie-Tooth, amyotrophic lateral sclerosis and hereditary spastic paraplegia. In most cases, symptoms start early in infancy, or in utero, and are slowly progressive. Additional neurological symptoms vary among non-related patients, probably because of their different VRK1 variants and their genetic background. The underlying common pathogenic mechanism, by its functional impairment, is a likely consequence of the roles that the VRK1 protein plays in the regulation on the stability and assembly of Cajal bodies, which affect RNA maturation and processing, neuronal migration of RNPs along axons, and DNA-damage responses. Alterations of these processes are associated with several neuro sensory or motor syndromes. The clinical heterogeneity of the neurological phenotypes associated with VRK1 is a likely consequence of the protein complexes in which VRK1 is integrated, which include several proteins known to be associated with Cajal bodies and DNA damage responses. Several hereditary distal neurological diseases are a consequence of pathogenic variants in genes that alter these cellular functions. We conclude that VRK1-related distal hereditary neuropathies and motor neuron diseases represent a novel subgroup of Cajal body related neurological syndromes.
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Affiliation(s)
- Pedro A Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain.
| | - Patricia Morejón-García
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain.
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5
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Zhang Y, Wang X, Wang H, Jiang Y, Xu Z, Luo L. Elevated Small Nuclear Ribonucleoprotein Polypeptide an Expression Correlated With Poor Prognosis and Immune Infiltrates in Patients With Hepatocellular Carcinoma. Front Oncol 2022; 12:893107. [PMID: 35860579 PMCID: PMC9290672 DOI: 10.3389/fonc.2022.893107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/07/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundElevated Small Nuclear Ribonucleoprotein Polypeptide A (SNRPA) can enhance tumor cell growth and proliferation in various cancers. However, rarely studies focus on the comprehensive analysis of SNRPA in hepatocellular carcinoma (HCC).MethodsTCGA and GEO databases were used to analyze the mRNA expression of SNRPA in HCC. Protein expression of SNAPA was validated using immunohistochemistry. Stably transfected HCC cells were used to investigate the role of SNRPA in the progression of HCC. The functional enrichment analysis was utilized for the biological function prediction. The CIBERSORT and ssGSEA algorithms were used to evaluate the composition of the tumor microenvironment and immunocyte infiltration ratio.ResultsThe SNRPA expression was upregulated in HCC and positively correlated with tumor stage and grade. SNRPA overexpression were independent risk factors for poor overall survival (OS) and recurrence-free survival (RFS). In patients with early-stage disease, low alpha-fetoprotein expression, and better differentiation, SNRPA still exhibited the excellent prognostic value. Knockdown of SNRPA inhibited the proliferation and migration while promoting the apoptosis of HCC cells. Higher methylation of the CpG site cg16596691 correlated with longer OS in HCC patients. Genes co-expressed with SNRPA were overexpressed in HCC and correlated with shorter OS. The GO and KEGG enrichment analysis showed that SNRPA expression was related to mRNA splicing, spliceosome signaling. GSEA demonstrated that the main enrichment pathway of SNRPA-related differential genes was spliceosome signaling, cell cycle signaling, P53 signaling pathway, T cell receptor signaling pathway, natural killer cell-mediated signaling. CIBERSORT and ssGSEA algorithm revealed that SNRPA was mainly associated with the higher proportion of CD8+T cells, T cells follicular helper, T cells regulatory, Macrophages M0, and the lower proportion of T cells CD4 memory resting, NK cells resting, Monocytes, and Mast cells resting.ConclusionElevated SNRPA enhances tumor cell proliferation and correlated with poor prognosis and immune infiltrates in patients with HCC.
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Affiliation(s)
- Youfu Zhang
- Department of Organ Transplantation, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
| | - Xuyang Wang
- Department of Organ Transplantation, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
| | - Huaxiang Wang
- Department of Hepatobiliary Surgery, The Fuzong Clinical Medical College of Fujian Medical University, Fuzhou, China
- Department of Hepatobiliary Surgery, 900 Hospital of the Joint Logistic Team, Fuzhou, China
| | - Yi Jiang
- Department of Hepatobiliary Surgery, The Fuzong Clinical Medical College of Fujian Medical University, Fuzhou, China
- Department of Hepatobiliary Surgery, 900 Hospital of the Joint Logistic Team, Fuzhou, China
| | - Zhidan Xu
- Department of Organ Transplantation, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
- *Correspondence: Laibang Luo, ; Zhidan Xu,
| | - Laibang Luo
- Department of Organ Transplantation, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
- *Correspondence: Laibang Luo, ; Zhidan Xu,
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Singh NN, O'Leary CA, Eich T, Moss WN, Singh RN. Structural Context of a Critical Exon of Spinal Muscular Atrophy Gene. Front Mol Biosci 2022; 9:928581. [PMID: 35847983 PMCID: PMC9283826 DOI: 10.3389/fmolb.2022.928581] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Humans contain two nearly identical copies of Survival Motor Neuron genes, SMN1 and SMN2. Deletion or mutation of SMN1 causes spinal muscular atrophy (SMA), one of the leading genetic diseases associated with infant mortality. SMN2 is unable to compensate for the loss of SMN1 due to predominant exon 7 skipping, leading to the production of a truncated protein. Antisense oligonucleotide and small molecule-based strategies aimed at the restoration of SMN2 exon 7 inclusion are approved therapies of SMA. Many cis-elements and transacting factors have been implicated in regulation of SMN exon 7 splicing. Also, several structural elements, including those formed by a long-distance interaction, have been implicated in the modulation of SMN exon 7 splicing. Several of these structures have been confirmed by enzymatic and chemical structure-probing methods. Additional structures formed by inter-intronic interactions have been predicted by computational algorithms. SMN genes generate a vast repertoire of circular RNAs through inter-intronic secondary structures formed by inverted Alu repeats present in large number in SMN genes. Here, we review the structural context of the exonic and intronic cis-elements that promote or prevent exon 7 recognition. We discuss how structural rearrangements triggered by single nucleotide substitutions could bring drastic changes in SMN2 exon 7 splicing. We also propose potential mechanisms by which inter-intronic structures might impact the splicing outcomes.
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Affiliation(s)
- Natalia N. Singh
- Department of Biomedical Science, Iowa State University, Ames, IA, United States
| | - Collin A. O'Leary
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Taylor Eich
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Walter N. Moss
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
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Schärfen L, Zigackova D, Reimer KA, Stark MR, Slat VA, Francoeur NJ, Wells ML, Zhou L, Blackshear PJ, Neugebauer KM, Rader SD. Identification of Alternative Polyadenylation in Cyanidioschyzon merolae Through Long-Read Sequencing of mRNA. Front Genet 2022; 12:818697. [PMID: 35154260 PMCID: PMC8831791 DOI: 10.3389/fgene.2021.818697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/22/2021] [Indexed: 12/04/2022] Open
Abstract
Alternative polyadenylation (APA) is widespread among metazoans and has been shown to have important impacts on mRNA stability and protein expression. Beyond a handful of well-studied organisms, however, its existence and consequences have not been well investigated. We therefore turned to the deep-branching red alga, Cyanidioschyzon merolae, to study the biology of polyadenylation in an organism highly diverged from humans and yeast. C. merolae is an acidothermophilic alga that lives in volcanic hot springs. It has a highly reduced genome (16.5 Mbp) and has lost all but 27 of its introns and much of its splicing machinery, suggesting that it has been under substantial pressure to simplify its RNA processing pathways. We used long-read sequencing to assess the key features of C. merolae mRNAs, including splicing status and polyadenylation cleavage site (PAS) usage. Splicing appears to be less efficient in C. merolae compared with yeast, flies, and mammalian cells. A high proportion of transcripts (63%) have at least two distinct PAS’s, and 34% appear to utilize three or more sites. The apparent polyadenylation signal UAAA is used in more than 90% of cases, in cells grown in both rich media or limiting nitrogen. Our documentation of APA for the first time in this non-model organism highlights its conservation and likely biological importance of this regulatory step in gene expression.
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Affiliation(s)
- Leonard Schärfen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Dagmar Zigackova
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Kirsten A. Reimer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Martha R. Stark
- Department of Chemistry, University of Northern British Columbia, Prince George, BC, Canada
| | - Viktor A. Slat
- Department of Chemistry, University of Northern British Columbia, Prince George, BC, Canada
| | - Nancy J. Francoeur
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Melissa L. Wells
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, United States
| | - Lecong Zhou
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, United States
| | - Perry J. Blackshear
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, United States
| | - Karla M. Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
- *Correspondence: Stephen D. Rader, ; Karla M. Neugebauer,
| | - Stephen D. Rader
- Department of Chemistry, University of Northern British Columbia, Prince George, BC, Canada
- *Correspondence: Stephen D. Rader, ; Karla M. Neugebauer,
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8
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Jobbins AM, Campagne S, Weinmeister R, Lucas CM, Gosliga AR, Clery A, Chen L, Eperon LP, Hodson MJ, Hudson AJ, Allain FHT, Eperon IC. Exon-independent recruitment of SRSF1 is mediated by U1 snRNP stem-loop 3. EMBO J 2022; 41:e107640. [PMID: 34779515 PMCID: PMC8724738 DOI: 10.15252/embj.2021107640] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 10/04/2021] [Accepted: 10/07/2021] [Indexed: 12/11/2022] Open
Abstract
SRSF1 protein and U1 snRNPs are closely connected splicing factors. They both stimulate exon inclusion, SRSF1 by binding to exonic splicing enhancer sequences (ESEs) and U1 snRNPs by binding to the downstream 5' splice site (SS), and both factors affect 5' SS selection. The binding of U1 snRNPs initiates spliceosome assembly, but SR proteins such as SRSF1 can in some cases substitute for it. The mechanistic basis of this relationship is poorly understood. We show here by single-molecule methods that a single molecule of SRSF1 can be recruited by a U1 snRNP. This reaction is independent of exon sequences and separate from the U1-independent process of binding to an ESE. Structural analysis and cross-linking data show that SRSF1 contacts U1 snRNA stem-loop 3, which is required for splicing. We suggest that the recruitment of SRSF1 to a U1 snRNP at a 5'SS is the basis for exon definition by U1 snRNP and might be one of the principal functions of U1 snRNPs in the core reactions of splicing in mammals.
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Affiliation(s)
- Andrew M Jobbins
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
MRC London Institute of Medical SciencesLondonUK
- Present address:
Institute of Clinical SciencesImperial College LondonLondonUK
| | - Sébastien Campagne
- Institute of BiochemistryETH ZürichSwitzerland
- Present address:
Inserm U1212CNRS UMR5320ARNA LaboratoryBordeaux CedexFrance
| | - Robert Weinmeister
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | - Christian M Lucas
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Alison R Gosliga
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
Institut für Industrielle GenetikAbt.(eilung) SystembiologieUniversität StuttgartStuttgartGermany
| | | | - Li Chen
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Lucy P Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Mark J Hodson
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Andrew J Hudson
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | | | - Ian C Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
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Novel insights into the pervasive role of RNA structure in post-transcriptional regulation of gene expression in plants. Biochem Soc Trans 2021; 49:1829-1839. [PMID: 34436520 PMCID: PMC8421050 DOI: 10.1042/bst20210318] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/09/2021] [Accepted: 08/11/2021] [Indexed: 12/30/2022]
Abstract
RNA folding is an intrinsic property of RNA that serves a key role in every step of post-transcriptional regulation of gene expression, from RNA maturation to translation in plants. Recent developments of genome-wide RNA structure profiling methods have transformed research in this area enabling focus to shift from individual molecules to the study of tens of thousands of RNAs. Here, we provide a comprehensive review of recent advances in the field. We discuss these new insights of RNA structure functionality within the context of post-transcriptional regulation including mRNA maturation, translation, and RNA degradation in plants. Notably, we also provide an overview of how plants exhibit different RNA structures in response to environmental changes.
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10
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Artemyeva-Isman OV, Porter ACG. U5 snRNA Interactions With Exons Ensure Splicing Precision. Front Genet 2021; 12:676971. [PMID: 34276781 PMCID: PMC8283771 DOI: 10.3389/fgene.2021.676971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 05/12/2021] [Indexed: 11/13/2022] Open
Abstract
Imperfect conservation of human pre-mRNA splice sites is necessary to produce alternative isoforms. This flexibility is combined with the precision of the message reading frame. Apart from intron-termini GU_AG and the branchpoint A, the most conserved are the exon-end guanine and +5G of the intron start. Association between these guanines cannot be explained solely by base-pairing with U1 snRNA in the early spliceosome complex. U6 succeeds U1 and pairs +5G in the pre-catalytic spliceosome, while U5 binds the exon end. Current U5 snRNA reconstructions by CryoEM cannot explain the conservation of the exon-end G. Conversely, human mutation analyses show that guanines of both exon termini can suppress splicing mutations. Our U5 hypothesis explains the mechanism of splicing precision and the role of these conserved guanines in the pre-catalytic spliceosome. We propose: (1) optimal binding register for human exons and U5-the exon junction positioned at U5Loop1 C39|C38; (2) common mechanism for base-pairing of human U5 snRNA with diverse exons and bacterial Ll.LtrB intron with new loci in retrotransposition-guided by base pair geometry; and (3) U5 plays a significant role in specific exon recognition in the pre-catalytic spliceosome. Statistical analyses showed increased U5 Watson-Crick pairs with the 5'exon in the absence of +5G at the intron start. In 5'exon positions -3 and -5, this effect is specific to U5 snRNA rather than U1 snRNA of the early spliceosome. Increased U5 Watson-Crick pairs with 3'exon position +1 coincide with substitutions of the conserved -3C at the intron 3'end. Based on mutation and X-ray evidence, we propose that -3C pairs with U2 G31 juxtaposing the branchpoint and the 3'intron end. The intron-termini pair, formed in the pre-catalytic spliceosome to be ready for transition after branching, and the early involvement of the 3'intron end ensure that the 3'exon contacts U5 in the pre-catalytic complex. We suggest that splicing precision is safeguarded cooperatively by U5, U6, and U2 snRNAs that stabilize the pre-catalytic complex by Watson-Crick base pairing. In addition, our new U5 model explains the splicing effect of exon-start +1G mutations: U5 Watson-Crick pairs with exon +2C/+3G strongly promote exon inclusion. We discuss potential applications for snRNA therapeutics and gene repair by reverse splicing.
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Affiliation(s)
- Olga V Artemyeva-Isman
- Gene Targeting Group, Centre for Haematology, Department of Immunology and Inflammation, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Andrew C G Porter
- Gene Targeting Group, Centre for Haematology, Department of Immunology and Inflammation, Faculty of Medicine, Imperial College London, London, United Kingdom
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11
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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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12
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Emery A, Swanstrom R. HIV-1: To Splice or Not to Splice, That Is the Question. Viruses 2021; 13:181. [PMID: 33530363 PMCID: PMC7912102 DOI: 10.3390/v13020181] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 02/05/2023] Open
Abstract
The transcription of the HIV-1 provirus results in only one type of transcript-full length genomic RNA. To make the mRNA transcripts for the accessory proteins Tat and Rev, the genomic RNA must completely splice. The mRNA transcripts for Vif, Vpr, and Env must undergo splicing but not completely. Genomic RNA (which also functions as mRNA for the Gag and Gag/Pro/Pol precursor polyproteins) must not splice at all. HIV-1 can tolerate a surprising range in the relative abundance of individual transcript types, and a surprising amount of aberrant and even odd splicing; however, it must not over-splice, which results in the loss of full-length genomic RNA and has a dramatic fitness cost. Cells typically do not tolerate unspliced/incompletely spliced transcripts, so HIV-1 must circumvent this cell policing mechanism to allow some splicing while suppressing most. Splicing is controlled by RNA secondary structure, cis-acting regulatory sequences which bind splicing factors, and the viral protein Rev. There is still much work to be done to clarify the combinatorial effects of these splicing regulators. These control mechanisms represent attractive targets to induce over-splicing as an antiviral strategy. Finally, splicing has been implicated in latency, but to date there is little supporting evidence for such a mechanism. In this review we apply what is known of cellular splicing to understand splicing in HIV-1, and present data from our newer and more sensitive deep sequencing assays quantifying the different HIV-1 transcript types.
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MESH Headings
- Alternative Splicing
- Exons
- Gene Expression Regulation, Viral
- HIV-1/genetics
- Nucleic Acid Conformation
- RNA Splicing
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Regulatory Sequences, Nucleic Acid
- Virus Latency/genetics
- rev Gene Products, Human Immunodeficiency Virus/genetics
- rev Gene Products, Human Immunodeficiency Virus/metabolism
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Affiliation(s)
- Ann Emery
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA;
| | - Ronald Swanstrom
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA;
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
- Center for AIDS Research, University of North Carolina, Chapel Hill, NC 27599, USA
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13
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Yuan M, Yu C, Chen X, Wu Y. Investigation on Potential Correlation Between Small Nuclear Ribonucleoprotein Polypeptide A and Lung Cancer. Front Genet 2021; 11:610704. [PMID: 33552128 PMCID: PMC7859448 DOI: 10.3389/fgene.2020.610704] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 12/29/2020] [Indexed: 12/25/2022] Open
Abstract
SNRPA (small nuclear ribonucleoprotein polypeptide A) gene is essential for the pre-mRNA splicing process. Using the available datasets of TCGA or GEO, we aimed at exploring the potential association between the SNRPA gene and lung cancer by several online tools (such as GEIPA2, MEXPRESS, Oncomine) and bioinformatics analysis software (R or GSEA). SNRPA was highly expressed in the tissues of lung adenocarcinoma (LUAD) and lung squamous cell carcinoma tissue (LUSC), compared with control tissues. The high SNRPA expression was associated with a poor survival prognosis of LUAD cases, while the genetic alteration within SNRPA was linked to the overall survival prognosis of LUSC cases. There was a potential correlation between promoter methylation and the expression of SNRPA for LUAD. Compared with normal tissues, we observed a higher phosphorylation level at the S115 site of SNRPA protein (NP_004587.1) (p = 0.002) in the primary LUAD tissues. The potential ATR kinase of the S115 site was predicted. Besides, SNRPA expression in lung cancer was negatively correlated with the infiltration level of M2 macrophage but positively correlated with that of Follicular B helper T cells, in both LUAD and LUSC. The enrichment analysis of SNRPA-correlated genes showed that cell cycle and ubiquitin mechanism-related issues were mainly observed for LUAD; however, RNA splicing-related cellular issues were mainly for LUSC. In summary, the SNRPA gene was identified as a potential prognosis biomarker of lung cancer, especially lung adenocarcinoma, which sheds new light on the association between the spliceosomal complex component and tumorigenesis.
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Affiliation(s)
- Maoxi Yuan
- Department of Thoracic Surgery, Linyi Central Hospital, Linyi, China
| | - Chunmei Yu
- Department of Thoracic Surgery, Linyi Central Hospital, Linyi, China
| | - Xin Chen
- Department of Thoracic Surgery, The People's Hospital of Feixian County, Linyi, China
| | - Yubing Wu
- Department of Thoracic Surgery, Linyi Central Hospital, Linyi, China
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14
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Liu Y, Liu X, Lin C, Jia X, Zhu H, Song J, Zhang Y. Noncoding RNAs regulate alternative splicing in Cancer. J Exp Clin Cancer Res 2021; 40:11. [PMID: 33407694 PMCID: PMC7789004 DOI: 10.1186/s13046-020-01798-2] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022] Open
Abstract
AS (alternative splicing) is a fundamental process by which a gene can generate multiple distinct mRNA transcripts to increase protein diversity. Defects in AS influence the occurrence and development of many diseases, including cancers, and are frequently found to participate in various aspects of cancer biology, such as promoting invasion, metastasis, apoptosis resistance and drug resistance. NcRNAs (noncoding RNAs) are an abundant class of RNAs that do not encode proteins. NcRNAs include miRNAs (microRNAs), lncRNAs (long noncoding RNAs), circRNAs (circular RNAs) and snRNAs (small nuclear RNAs) and have been proven to act as regulatory molecules that mediate cancer processes through AS. NcRNAs can directly or indirectly influence a plethora of molecular targets to regulate cis-acting elements, trans-acting factors, or pre-mRNA transcription at multiple levels, affecting the AS process and generating alternatively spliced isoforms. Consequently, ncRNA-mediated AS outcomes affect multiple cellular signaling pathways that promote or suppress cancer progression. In this review, we summarize the current mechanisms by which ncRNAs regulate AS in cancers and discuss their potential clinical applications as biomarkers and therapeutic targets.
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Affiliation(s)
- Yunze Liu
- Department of General Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
- Department of Traditional Chinese Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
| | - Xin Liu
- Department of Endocrinology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
| | - Changwei Lin
- Department of Gastrointestinal Surgery, the Third XiangYa Hospital of Central South University, Changsha, 410013, China
| | - Xianhong Jia
- Department of Traditional Chinese Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
| | - Hongmei Zhu
- Department of Traditional Chinese Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
| | - Jun Song
- Department of General Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China.
| | - Yi Zhang
- Department of General Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China.
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15
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Singh RN, Ottesen EW, Singh NN. The First Orally Deliverable Small Molecule for the Treatment of Spinal Muscular Atrophy. Neurosci Insights 2020; 15:2633105520973985. [PMID: 33283185 PMCID: PMC7691903 DOI: 10.1177/2633105520973985] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is 1 of the leading causes of infant mortality. SMA
is mostly caused by low levels of Survival Motor Neuron (SMN) protein due to
deletion of or mutation in the SMN1 gene. Its nearly identical
copy, SMN2, fails to compensate for the loss of
SMN1 due to predominant skipping of exon 7. Correction of
SMN2 exon 7 splicing by an antisense oligonucleotide (ASO),
nusinersen (Spinraza™), that targets the intronic splicing silencer N1 (ISS-N1)
became the first approved therapy for SMA. Restoration of SMN levels using gene
therapy was the next. Very recently, an orally deliverable small molecule,
risdiplam (Evrysdi™), became the third approved therapy for SMA. Here we discuss
how these therapies are positioned to meet the needs of the broad phenotypic
spectrum of SMA patients.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
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16
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Ottesen EW, Singh RN. Characteristics of circular RNAs generated by human Survival Motor Neuron genes. Cell Signal 2020; 73:109696. [PMID: 32553550 PMCID: PMC7387165 DOI: 10.1016/j.cellsig.2020.109696] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 06/12/2020] [Indexed: 02/06/2023]
Abstract
Circular RNAs (circRNAs) belong to a diverse class of stable RNAs expressed in all cell types. Their proposed functions include sponging of microRNAs (miRNAs), sequestration and trafficking of proteins, assembly of multimeric complexes, production of peptides, and regulation of transcription. Backsplicing due to RNA structures formed by an exceptionally high number of Alu repeats lead to the production of a vast repertoire of circRNAs by human Survival Motor Neuron genes, SMN1 and SMN2, that code for SMN, an essential multifunctional protein. Low levels of SMN due to deletion or mutation of SMN1 result in spinal muscular atrophy (SMA), a major genetic disease of infants and children. Mild SMA is also recorded in adult population, expanding the spectrum of the disease. Here we review SMN circRNAs with respect to their biogenesis, sequence features, and potential functions. We also discuss how SMN circRNAs could be exploited for diagnostic and therapeutic purposes.
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Affiliation(s)
- Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States of America
| | - Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States of America.
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17
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Erkelenz S, Poschmann G, Ptok J, Müller L, Schaal H. Profiling of cis- and trans-acting factors supporting noncanonical splice site activation. RNA Biol 2020; 18:118-130. [PMID: 32693676 DOI: 10.1080/15476286.2020.1798111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Recently, by combining transcriptomics with functional splicing reporter assays we were able to identify GT > GC > TT as the three highest ranked dinucleotides of human 5' splice sites (5'ss). Here, we have extended our investigations to the proteomic characterization of nuclear proteins that bind to canonical and noncanonical 5'ss. Surprisingly, we found that U1 snRNP binding to functional 5'ss sequences prevented components of the DNA damage response (DDR) from binding to the RNA, suggesting a close link between spliceosome arrangement and genome stability. We demonstrate that all tested noncanonical 5'ss sequences are bona-fide targets of the U2-type spliceosome and are bound by U1 snRNP, including U1-C, in the presence of splicing enhancers. The quantity of precipitated U1-C protein was similar for all noncanonical 5'ss dinucleotides, so that the highly different 5'ss usage was likely due to a later step after early U1 snRNP binding. In addition, we show that an internal GT at positions +5/+6 can be advantageous for splicing at position +1 of noncanonical splice sites. Likewise, and in agreement with previous observations, splicing inactive U1 snRNP binding sites could serve as splicing enhancers, which may also explain the higher abundance of U1 snRNPs compared to other U snRNPs. Finally, we observe that an arginine-serine (RS)-rich domain recruitment to stem loop I of the U1 snRNA is functionally sufficient to promote exon-definition and upstream 3'ss activation.
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Affiliation(s)
- Steffen Erkelenz
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf , Düsseldorf, Germany.,Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne , Cologne, Germany
| | - Gereon Poschmann
- Molecular Proteomics Laboratory, BMFZ, Universitätsklinikum Düsseldorf , Düsseldorf, Germany
| | - Johannes Ptok
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf , Düsseldorf, Germany
| | - Lisa Müller
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf , Düsseldorf, Germany
| | - Heiner Schaal
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf , Düsseldorf, Germany
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18
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Singh NN, Ottesen EW, Singh RN. A survey of transcripts generated by spinal muscular atrophy genes. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2020; 1863:194562. [PMID: 32387331 PMCID: PMC7302838 DOI: 10.1016/j.bbagrm.2020.194562] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/01/2020] [Accepted: 04/13/2020] [Indexed: 02/07/2023]
Abstract
Human Survival Motor Neuron (SMN) genes code for SMN, an essential multifunctional protein. Complete loss of SMN is embryonic lethal, while low levels of SMN lead to spinal muscular atrophy (SMA), a major genetic disease of children and infants. Reduced levels of SMN are associated with the abnormal development of heart, lung, muscle, gastro-intestinal system and testis. The SMN loci have been shown to generate a vast repertoire of transcripts, including linear, back- and trans-spliced RNAs as well as antisense long noncoding RNAs. However, functions of the majority of these transcripts remain unknown. Here we review the nature of RNAs generated from the SMN loci and discuss their potential functions in cellular metabolism.
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Affiliation(s)
- Natalia N Singh
- Department of Biomedical Science, Iowa State University, Ames, IA, 50011, United States of America
| | - Eric W Ottesen
- Department of Biomedical Science, Iowa State University, Ames, IA, 50011, United States of America
| | - Ravindra N Singh
- Department of Biomedical Science, Iowa State University, Ames, IA, 50011, United States of America.
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19
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Singh RN, Seo J, Singh NN. RNA in spinal muscular atrophy: therapeutic implications of targeting. Expert Opin Ther Targets 2020; 24:731-743. [PMID: 32538213 DOI: 10.1080/14728222.2020.1783241] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Spinal muscular atrophy (SMA) is caused by low levels of the Survival Motor Neuron (SMN) protein due to deletions of or mutations in the SMN1 gene. Humans carry another nearly identical gene, SMN2, which mostly produces a truncated and less stable protein SMNΔ7 due to predominant skipping of exon 7. Elevation of SMN upon correction of SMN2 exon 7 splicing and gene therapy have been proven to be the effective treatment strategies for SMA. AREAS COVERED This review summarizes existing and potential SMA therapies that are based on RNA targeting.We also discuss the mechanistic basis of RNA-targeting molecules. EXPERT OPINION The discovery of intronic splicing silencer N1 (ISS-N1) was the first major step towards developing the currently approved antisense-oligonucleotide (ASO)-directed therapy (SpinrazaTM) based on the correction of exon 7 splicing of the endogenous SMN2pre-mRNA. Recently, gene therapy (Zolgensma) has become the second approved treatment for SMA. Small compounds (currently in clinical trials) capable of restoring SMN2 exon 7 inclusion further expand the class of the RNA targeting molecules for SMA therapy. Endogenous RNA targets, such as long non-coding RNAs, circular RNAs, microRNAs and ribonucleoproteins, could be potentially exploited for developing additional SMA therapies.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University , Ames, IA, USA
| | - Joonbae Seo
- Department of Biomedical Sciences, Iowa State University , Ames, IA, USA
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University , Ames, IA, USA
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20
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Ambrose RL, Brice AM, Caputo AT, Alexander MR, Tribolet L, Liu YC, Adams TE, Bean AG, Stewart CR. Molecular characterisation of ILRUN, a novel inhibitor of proinflammatory and antimicrobial cytokines. Heliyon 2020; 6:e04115. [PMID: 32518853 PMCID: PMC7270589 DOI: 10.1016/j.heliyon.2020.e04115] [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: 01/28/2020] [Revised: 04/28/2020] [Accepted: 05/28/2020] [Indexed: 12/15/2022] Open
Abstract
Regulation of type-I interferon (IFN) production is essential to the balance between antimicrobial defence and autoimmune disorders. The human protein-coding gene ILRUN (inflammation and lipid regulator with UBA-like and NBR1-like domains, previously C6orf106) was recently characterised as an inhibitor of antiviral and proinflammatory cytokine (interferon-alpha/beta and tumor necrosis factor alpha) transcription. Currently there is a paucity of information about the molecular characteristics of ILRUN, despite it being associated with several diseases including virus infection, coronary artery disease, obesity and cancer. Here, we characterise ILRUN as a highly phylogenetically conserved protein containing UBA-like and a NBR1-like domains that are both essential for inhibition of type-I interferon and tumor necrosis factor alpha) transcription in human cells. We also solved the crystal structure of the NBR1-like domain, providing insights into its potential role in ILRUN function. This study provides critical information for future investigations into the role of ILRUN in health and disease.
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Affiliation(s)
- Rebecca L. Ambrose
- CSIRO Health & Biosecurity, Australian Centre for Disease Preparedness, Geelong, Victoria, 3220, Australia
| | - Aaron M. Brice
- CSIRO Health & Biosecurity, Australian Centre for Disease Preparedness, Geelong, Victoria, 3220, Australia
| | | | - Marina R. Alexander
- CSIRO Health & Biosecurity, Australian Centre for Disease Preparedness, Geelong, Victoria, 3220, Australia
| | - Leon Tribolet
- CSIRO Health & Biosecurity, Australian Centre for Disease Preparedness, Geelong, Victoria, 3220, Australia
| | - Yu Chih Liu
- CSIRO Manufacturing, Parkville, Victoria, 3010, Australia
| | | | - Andrew G.D. Bean
- CSIRO Health & Biosecurity, Australian Centre for Disease Preparedness, Geelong, Victoria, 3220, Australia
| | - Cameron R. Stewart
- CSIRO Health & Biosecurity, Australian Centre for Disease Preparedness, Geelong, Victoria, 3220, Australia
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21
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Abou Alezz M, Celli L, Belotti G, Lisa A, Bione S. GC-AG Introns Features in Long Non-coding and Protein-Coding Genes Suggest Their Role in Gene Expression Regulation. Front Genet 2020; 11:488. [PMID: 32499820 PMCID: PMC7242645 DOI: 10.3389/fgene.2020.00488] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/20/2020] [Indexed: 12/16/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) are recognized as an important class of regulatory molecules involved in a variety of biological functions. However, the regulatory mechanisms of long non-coding genes expression are still poorly understood. The characterization of the genomic features of lncRNAs is crucial to get insight into their function. In this study, we exploited recent annotations by GENCODE to characterize the genomic and splicing features of long non-coding genes in comparison with protein-coding ones, both in human and mouse. Our analysis highlighted differences between the two classes of genes in terms of their gene architecture. Significant differences in the splice sites usage were observed between long non-coding and protein-coding genes (PCG). While the frequency of non-canonical GC-AG splice junctions represents about 0.8% of total splice sites in PCGs, we identified a significant enrichment of the GC-AG splice sites in long non-coding genes, both in human (3.0%) and mouse (1.9%). In addition, we found a positional bias of GC-AG splice sites being enriched in the first intron in both classes of genes. Moreover, a significant shorter length and weaker donor and acceptor sites were found comparing GC-AG introns to GT-AG introns. Genes containing at least one GC-AG intron were found conserved in many species, more prone to alternative splicing and a functional analysis pointed toward their enrichment in specific biological processes such as DNA repair. Our study shows for the first time that GC-AG introns are mainly associated with lncRNAs and are preferentially located in the first intron. Additionally, we discovered their regulatory potential indicating the existence of a new mechanism of non-coding and PCGs expression regulation.
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Affiliation(s)
- Monah Abou Alezz
- Computational Biology Unit, Institute of Molecular Genetics Luigi Luca Cavalli-Sforza, National Research Council, Pavia, Italy
| | - Ludovica Celli
- Computational Biology Unit, Institute of Molecular Genetics Luigi Luca Cavalli-Sforza, National Research Council, Pavia, Italy
| | - Giulia Belotti
- Computational Biology Unit, Institute of Molecular Genetics Luigi Luca Cavalli-Sforza, National Research Council, Pavia, Italy
| | - Antonella Lisa
- Computational Biology Unit, Institute of Molecular Genetics Luigi Luca Cavalli-Sforza, National Research Council, Pavia, Italy
| | - Silvia Bione
- Computational Biology Unit, Institute of Molecular Genetics Luigi Luca Cavalli-Sforza, National Research Council, Pavia, Italy
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22
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Marcos AT, Martín‐Doncel E, Morejón‐García P, Marcos‐Alcalde I, Gómez‐Puertas P, Segura‐Puimedon M, Armengol L, Navarro‐Pando JM, Lazo PA. VRK1 (Y213H) homozygous mutant impairs Cajal bodies in a hereditary case of distal motor neuropathy. Ann Clin Transl Neurol 2020; 7:808-818. [PMID: 32365420 PMCID: PMC7261760 DOI: 10.1002/acn3.51050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 03/27/2020] [Accepted: 03/31/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Distal motor neuropathies with a genetic origin have a heterogeneous clinical presentation with overlapping features affecting distal nerves and including spinal muscular atrophies and amyotrophic lateral sclerosis. This indicates that their genetic background is heterogeneous. PATIENT AND METHODS In this work, we have identified and characterized the genetic and molecular base of a patient with a distal sensorimotor neuropathy of unknown origin. For this study, we performed whole-exome sequencing, molecular modelling, cloning and expression of mutant gene, and biochemical and cell biology analysis of the mutant protein. RESULTS A novel homozygous recessive mutation in the human VRK1 gene, coding for a chromatin kinase, causing a substitution (c.637T > C; p.Tyr213His) in exon 8, was detected in a patient presenting since childhood a progressive distal sensorimotor neuropathy and spinal muscular atrophy syndrome, with normal intellectual development. Molecular modelling predicted this mutant VRK1 has altered the kinase activation loop by disrupting its interaction with the C-terminal regulatory region. The p.Y213H mutant protein has a reduced kinase activity with different substrates, including histones H3 and H2AX, proteins involved in DNA damage responses, such as p53 and 53BP1, and coilin, the scaffold for Cajal bodies. The mutant VRK1(Y213H) protein is unable to rescue the formation of Cajal bodies assembled on coilin, in the absence of wild-type VRK1. CONCLUSION The VRK1(Y213H) mutant protein alters the activation loop, impairs the kinase activity of VRK1 causing a functional insufficiency that impairs the formation of Cajal bodies assembled on coilin, a protein that regulates SMN1 and Cajal body formation.
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Affiliation(s)
- Ana T. Marcos
- Unidad de GenéticaInstituto para el Estudio de la Biología de la Reproducción Humana (INEBIR)SevillaSpain
| | - Elena Martín‐Doncel
- Molecular Mechanisms of Cancer ProgramInstituto de Biología Molecular y Celular del CáncerConsejo Superior de Investigaciones Científicas (CSIC)Universidad de SalamancaSalamancaSpain
- Instituto de Investigación Biomédica de Salamanca (IBSAL)Hospital Universitario de SalamancaSalamancaSpain
| | - Patricia Morejón‐García
- Molecular Mechanisms of Cancer ProgramInstituto de Biología Molecular y Celular del CáncerConsejo Superior de Investigaciones Científicas (CSIC)Universidad de SalamancaSalamancaSpain
- Instituto de Investigación Biomédica de Salamanca (IBSAL)Hospital Universitario de SalamancaSalamancaSpain
| | - Iñigo Marcos‐Alcalde
- Molecular Modelling GroupCentro de Biología Molecular “Severo Ochoa”CSIC‐Universidad Autónoma de Madrid, CantoblancoMadridSpain
- School of Experimental SciencesBiosciences Research InstituteUniversidad Francisco de VitoriaPozuelo de Alarcón, MadridSpain
| | - Paulino Gómez‐Puertas
- Molecular Modelling GroupCentro de Biología Molecular “Severo Ochoa”CSIC‐Universidad Autónoma de Madrid, CantoblancoMadridSpain
| | - María Segura‐Puimedon
- Quantitative Genomic Medicine Laboratories, qGenomicsEspluges de LlobregatBarcelonaSpain
| | - Lluis Armengol
- Quantitative Genomic Medicine Laboratories, qGenomicsEspluges de LlobregatBarcelonaSpain
| | - José M. Navarro‐Pando
- Unidad de GenéticaInstituto para el Estudio de la Biología de la Reproducción Humana (INEBIR)SevillaSpain
- Cátedra de Reproducción y Genética HumanaFacultad de Ciencias de la SaludUniversidad Europea del AtlánticoSantanderSpain
- Fundación Universitaria Iberoamericana (FUNIBER)BarcelonaSpain
| | - Pedro A. Lazo
- Molecular Mechanisms of Cancer ProgramInstituto de Biología Molecular y Celular del CáncerConsejo Superior de Investigaciones Científicas (CSIC)Universidad de SalamancaSalamancaSpain
- Instituto de Investigación Biomédica de Salamanca (IBSAL)Hospital Universitario de SalamancaSalamancaSpain
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Lopez Soto EJ, Gandal MJ, Gonatopoulos-Pournatzis T, Heller EA, Luo D, Zheng S. Mechanisms of Neuronal Alternative Splicing and Strategies for Therapeutic Interventions. J Neurosci 2019; 39:8193-8199. [PMID: 31619487 PMCID: PMC6794923 DOI: 10.1523/jneurosci.1149-19.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/09/2019] [Accepted: 08/10/2019] [Indexed: 01/15/2023] Open
Abstract
Many cellular and physiological processes are coordinated by regulatory networks that produce a remarkable complexity of transcript isoforms. In the mammalian nervous system, alternative pre-mRNA splicing generates functionally distinct isoforms that play key roles in normal physiology, supporting development, plasticity, complex behaviors, and cognition. Neuronal splicing programs controlled by RNA-binding proteins, are influenced by chromatin modifications and can exhibit neuronal subtype specificity. As highlighted in recent publications, aberrant alternative splicing is a major contributor to disease phenotypes. Therefore, understanding the underlying mechanisms of alternative splicing regulation and identifying functional splicing isoforms with critical phenotypic roles are expected to provide a comprehensive resource for therapeutic development, as illuminated by recent successful interventions of spinal muscular atrophy. Here, we discuss the latest progress in the study of the emerging complexity of alternative splicing mechanisms in neurons, and how these findings inform new therapies to correct and control splicing defects.
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Affiliation(s)
| | - Michael J Gandal
- Department of Psychiatry, Semel Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095
| | | | - Elizabeth A Heller
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-5158
| | - Diou Luo
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa 50011, and
| | - Sika Zheng
- Division of Biomedical Sciences, University of California at Riverside, Riverside, California 92521
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Singh NN, Singh RN. How RNA structure dictates the usage of a critical exon of spinal muscular atrophy gene. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194403. [PMID: 31323435 DOI: 10.1016/j.bbagrm.2019.07.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 07/09/2019] [Indexed: 12/17/2022]
Abstract
Role of RNA structure in pre-mRNA splicing has been implicated for several critical exons associated with genetic disorders. However, much of the structural studies linked to pre-mRNA splicing regulation are limited to terminal stem-loop structures (hairpins) sequestering splice sites. In few instances, role of long-distance interactions is implicated as the major determinant of splicing regulation. With the recent surge of reports of circular RNA (circRNAs) generated by backsplicing, role of Alu-associated RNA structures formed by long-range interactions are taking central stage. Humans contain two nearly identical copies of Survival Motor Neuron (SMN) genes, SMN1 and SMN2. Deletion or mutation of SMN1 coupled with the inability of SMN2 to compensate for the loss of SMN1 due to exon 7 skipping causes spinal muscular atrophy (SMA), one of the leading genetic diseases of children. In this review, we describe how structural elements formed by both local and long-distance interactions are being exploited to modulate SMN2 exon 7 splicing as a potential therapy for SMA. We also discuss how Alu-associated secondary structure modulates generation of a vast repertoire of SMN circRNAs. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Natalia N Singh
- Department of Biomedical Science, Iowa State University, Ames, IA 50011, United States of America
| | - Ravindra N Singh
- Department of Biomedical Science, Iowa State University, Ames, IA 50011, United States of America.
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