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de Jong MJ, van Oosterhout C, Hoelzel AR, Janke A. Moderating the neutralist-selectionist debate: exactly which propositions are we debating, and which arguments are valid? Biol Rev Camb Philos Soc 2024; 99:23-55. [PMID: 37621151 DOI: 10.1111/brv.13010] [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: 03/15/2022] [Revised: 08/04/2023] [Accepted: 08/07/2023] [Indexed: 08/26/2023]
Abstract
Half a century after its foundation, the neutral theory of molecular evolution continues to attract controversy. The debate has been hampered by the coexistence of different interpretations of the core proposition of the neutral theory, the 'neutral mutation-random drift' hypothesis. In this review, we trace the origins of these ambiguities and suggest potential solutions. We highlight the difference between the original, the revised and the nearly neutral hypothesis, and re-emphasise that none of them equates to the null hypothesis of strict neutrality. We distinguish the neutral hypothesis of protein evolution, the main focus of the ongoing debate, from the neutral hypotheses of genomic and functional DNA evolution, which for many species are generally accepted. We advocate a further distinction between a narrow and an extended neutral hypothesis (of which the latter posits that random non-conservative amino acid substitutions can cause non-ecological phenotypic divergence), and we discuss the implications for evolutionary biology beyond the domain of molecular evolution. We furthermore point out that the debate has widened from its initial focus on point mutations, and also concerns the fitness effects of large-scale mutations, which can alter the dosage of genes and regulatory sequences. We evaluate the validity of neutralist and selectionist arguments and find that the tested predictions, apart from being sensitive to violation of underlying assumptions, are often derived from the null hypothesis of strict neutrality, or equally consistent with the opposing selectionist hypothesis, except when assuming molecular panselectionism. Our review aims to facilitate a constructive neutralist-selectionist debate, and thereby to contribute to answering a key question of evolutionary biology: what proportions of amino acid and nucleotide substitutions and polymorphisms are adaptive?
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Affiliation(s)
- Menno J de Jong
- Senckenberg Biodiversity and Climate Research Institute (SBiK-F), Georg-Voigt-Strasse 14-16, Frankfurt am Main, 60325, Germany
| | - Cock van Oosterhout
- Centre for Ecology, Evolution and Conservation, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - A Rus Hoelzel
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Axel Janke
- Senckenberg Biodiversity and Climate Research Institute (SBiK-F), Georg-Voigt-Strasse 14-16, Frankfurt am Main, 60325, Germany
- Institute for Ecology, Evolution and Diversity, Goethe University, Max-von-Laue-Strasse 9, Frankfurt am Main, 60438, Germany
- LOEWE-Centre for Translational Biodiversity Genomics (TBG), Senckenberg Nature Research Society, Georg-Voigt-Straße 14-16, Frankfurt am Main, 60325, Germany
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Putscher E, Hecker M, Fitzner B, Lorenz P, Zettl UK. Principles and Practical Considerations for the Analysis of Disease-Associated Alternative Splicing Events Using the Gateway Cloning-Based Minigene Vectors pDESTsplice and pSpliceExpress. Int J Mol Sci 2021; 22:5154. [PMID: 34068052 PMCID: PMC8152502 DOI: 10.3390/ijms22105154] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/23/2022] Open
Abstract
Splicing is an important RNA processing step. Genetic variations can alter the splicing process and thereby contribute to the development of various diseases. Alterations of the splicing pattern can be examined by gene expression analyses, by computational tools for predicting the effects of genetic variants on splicing, and by splicing reporter minigene assays for studying alternative splicing events under defined conditions. The minigene assay is based on transient transfection of cells with a vector containing a genomic region of interest cloned between two constitutive exons. Cloning can be accomplished by the use of restriction enzymes or by site-specific recombination using Gateway cloning. The vectors pDESTsplice and pSpliceExpress represent two minigene systems based on Gateway cloning, which are available through the Addgene plasmid repository. In this review, we describe the features of these two splicing reporter minigene systems. Moreover, we provide an overview of studies in which determinants of alternative splicing were investigated by using pDESTsplice or pSpliceExpress. The studies were reviewed with regard to the investigated splicing regulatory events and the experimental strategy to construct and perform a splicing reporter minigene assay. We further elaborate on how analyses on the regulation of RNA splicing offer promising prospects for gaining important insights into disease mechanisms.
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Affiliation(s)
- Elena Putscher
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Street 20, 18147 Rostock, Germany; (E.P.); (B.F.); (U.K.Z.)
| | - Michael Hecker
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Street 20, 18147 Rostock, Germany; (E.P.); (B.F.); (U.K.Z.)
| | - Brit Fitzner
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Street 20, 18147 Rostock, Germany; (E.P.); (B.F.); (U.K.Z.)
| | - Peter Lorenz
- Rostock University Medical Center, Institute of Immunology, Schillingallee 70, 18057 Rostock, Germany;
| | - Uwe Klaus Zettl
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Street 20, 18147 Rostock, Germany; (E.P.); (B.F.); (U.K.Z.)
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Joynt AT, Evans TA, Pellicore MJ, Davis-Marcisak EF, Aksit MA, Eastman AC, Patel SU, Paul KC, Osorio DL, Bowling AD, Cotton CU, Raraigh KS, West NE, Merlo CA, Cutting GR, Sharma N. Evaluation of both exonic and intronic variants for effects on RNA splicing allows for accurate assessment of the effectiveness of precision therapies. PLoS Genet 2020; 16:e1009100. [PMID: 33085659 PMCID: PMC7605713 DOI: 10.1371/journal.pgen.1009100] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 11/02/2020] [Accepted: 09/08/2020] [Indexed: 12/21/2022] Open
Abstract
Elucidating the functional consequence of molecular defects underlying genetic diseases enables appropriate design of therapeutic options. Treatment of cystic fibrosis (CF) is an exemplar of this paradigm as the development of CFTR modulator therapies has allowed for targeted and effective treatment of individuals harboring specific genetic variants. However, the mechanism of these drugs limits effectiveness to particular classes of variants that allow production of CFTR protein. Thus, assessment of the molecular mechanism of individual variants is imperative for proper assignment of these precision therapies. This is particularly important when considering variants that affect pre-mRNA splicing, thus limiting success of the existing protein-targeted therapies. Variants affecting splicing can occur throughout exons and introns and the complexity of the process of splicing lends itself to a variety of outcomes, both at the RNA and protein levels, further complicating assessment of disease liability and modulator response. To investigate the scope of this challenge, we evaluated splicing and downstream effects of 52 naturally occurring CFTR variants (exonic = 15, intronic = 37). Expression of constructs containing select CFTR intronic sequences and complete CFTR exonic sequences in cell line models allowed for assessment of RNA and protein-level effects on an allele by allele basis. Characterization of primary nasal epithelial cells obtained from individuals harboring splice variants corroborated in vitro data. Notably, we identified exonic variants that result in complete missplicing and thus a lack of modulator response (e.g. c.2908G>A, c.523A>G), as well as intronic variants that respond to modulators due to the presence of residual normally spliced transcript (e.g. c.4242+2T>C, c.3717+40A>G). Overall, our data reveals diverse molecular outcomes amongst both exonic and intronic variants emphasizing the need to delineate RNA, protein, and functional effects of each variant in order to accurately assign precision therapies. Genetic variants that impact pre-mRNA splicing are a common cause of genetic disease and have varying downstream molecular consequences. As a result, precision therapies that function at the protein level are not always effective for these variants and thus careful assessment is necessary. Here we evaluate RNA-level effects of 52 variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and show that study of splicing and its consequences allows for more accurate assignment of precision therapies.
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Affiliation(s)
- Anya T. Joynt
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Taylor A. Evans
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Matthew J. Pellicore
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Emily F. Davis-Marcisak
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Melis A. Aksit
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alice C. Eastman
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shivani U. Patel
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Kathleen C. Paul
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Derek L. Osorio
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alyssa D. Bowling
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Calvin U. Cotton
- Departments of Pediatrics, Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Karen S. Raraigh
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Natalie E. West
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Christian A. Merlo
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Garry R. Cutting
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (GRC); (NS)
| | - Neeraj Sharma
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (GRC); (NS)
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Michaels WE, Bridges RJ, Hastings ML. Antisense oligonucleotide-mediated correction of CFTR splicing improves chloride secretion in cystic fibrosis patient-derived bronchial epithelial cells. Nucleic Acids Res 2020; 48:7454-7467. [PMID: 32520327 PMCID: PMC7367209 DOI: 10.1093/nar/gkaa490] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 05/22/2020] [Accepted: 06/05/2020] [Indexed: 12/27/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, encoding an anion channel that conducts chloride and bicarbonate across epithelial membranes. Mutations that disrupt pre-mRNA splicing occur in >15% of CF cases. One common CFTR splicing mutation is CFTR c.3718-2477C>T (3849+10 kb C>T), which creates a new 5′ splice site, resulting in splicing to a cryptic exon with a premature termination codon. Splice-switching antisense oligonucleotides (ASOs) have emerged as an effective therapeutic strategy to block aberrant splicing. We test an ASO targeting the CFTR c.3718-2477C>T mutation and show that it effectively blocks aberrant splicing in primary bronchial epithelial (hBE) cells from CF patients with the mutation. ASO treatment results in long-term improvement in CFTR activity in hBE cells, as demonstrated by a recovery of chloride secretion and apical membrane conductance. We also show that the ASO is more effective at recovering chloride secretion in our assay than ivacaftor, the potentiator treatment currently available to these patients. Our findings demonstrate the utility of ASOs in correcting CFTR expression and channel activity in a manner expected to be therapeutic in patients.
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Affiliation(s)
- Wren E Michaels
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.,School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Robert J Bridges
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Michelle L Hastings
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
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Tang M, Alaniz ME, Felsky D, Vardarajan B, Reyes-Dumeyer D, Lantigua R, Medrano M, Bennett DA, de Jager PL, Mayeux R, Santa-Maria I, Reitz C. Synonymous variants associated with Alzheimer disease in multiplex families. Neurol Genet 2020; 6:e450. [PMID: 32637632 PMCID: PMC7323483 DOI: 10.1212/nxg.0000000000000450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 05/05/2020] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Synonymous variants can lead to disease; nevertheless, the majority of sequencing studies conducted in Alzheimer disease (AD) only assessed coding variation. METHODS To detect synonymous variants modulating AD risk, we conducted a whole-genome sequencing study on 67 Caribbean Hispanic (CH) families multiply affected by AD. Identified disease-associated variants were further assessed in an independent cohort of CHs, expression quantitative trait locus (eQTL) data, brain autopsy data, and functional experiments. RESULTS Rare synonymous variants in 4 genes (CDH23, SLC9A3R1, RHBDD2, and ITIH2) segregated with AD status in multiplex families and had a significantly higher frequency in these families compared with reference populations of similar ancestry. In comparison to subjects without dementia, expression of CDH23 (β = 0.53, p = 0.006) and SLC9A3R1 (β = 0.50, p = 0.02) was increased, and expression of RHBDD2 (β = -0.70, p = 0.02) decreased in individuals with AD at death. In line with this finding, increased expression of CDH23 (β = 0.26 ± 0.08, p = 4.9E-4) and decreased expression of RHBDD2 (β = -0.60 ± 0.12, p = 5.5E-7) were related to brain amyloid load (p = 0.0025). SLC9A3R1 expression was associated with burden of TDP43 pathology (β = 0.58 ± 0.17, p = 5.9E-4). Using eQTL data, the CDH23 variant was in linkage disequilibrium with variants modulating CDH23 expression levels (top single nucleotide polymorphism: rs11000035, p = 4.85E-6, D' = 1.0). Using minigene splicing assays, the CDH23 and SLC9A3R1 variants affected splicing efficiency. CONCLUSIONS These findings suggest that CDH23, SLC9A3R1, RHBDD2, and possibly ITIH2, which are involved in synaptic function, the glutamatergic system, and innate immunity, contribute to AD etiology. In addition, this study supports the notion that synonymous variants contribute to AD risk and that comprehensive scrutinization of this type of genetic variation is warranted and critical.
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Affiliation(s)
- Min Tang
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Maria Eugenia Alaniz
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Daniel Felsky
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Badri Vardarajan
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Dolly Reyes-Dumeyer
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Rafael Lantigua
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Martin Medrano
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - David A Bennett
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Philip L de Jager
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Richard Mayeux
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Ismael Santa-Maria
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Christiane Reitz
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain (M.E.A., B.V., R.L., P.L.J., R.M., I.S.-M., C.R.); The Gertrude H. Sergievsky Center (M.T., D.R.-D., R.L., R.M., C.R.); Department of Neurology (P.L.J., R.M., C.R.); Department of Epidemiology (R.M., C.R.); Department of Psychiatry (R.M.), Columbia University, New York; Department of Pathology and Cell Biology (M.E.A., I.S.-M.), Columbia University, New York; Rush Alzheimer's Disease Center (D.A.B.); Department of Neurological Sciences (D.A.B.); Department of Pathology (D.A.B.), Rush University Medical Center, Chicago, IL; Center for Innovation in Brain Science , Departments of Pharmacology and Neurology , University of Arizona College of Medicine (M.T.), Tucson; Department of Medicine (R.L.), College of Physicians and Surgeons, Columbia University, New York, NY; School of Medicine (M.M.), Mother and Teacher Pontifical Catholic University, Santiago, Dominican Republic; and The Krembil Centre for Neuroinformatics (D.F.), Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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Gotea V, Margolin G, Elnitski L. CAGI experiments: Modeling sequence variant impact on gene splicing using predictions from computational tools. Hum Mutat 2019; 40:1252-1260. [PMID: 31066132 DOI: 10.1002/humu.23782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 04/12/2019] [Accepted: 05/04/2019] [Indexed: 01/12/2023]
Abstract
Improving predictions of phenotypic consequences for genomic variants is part of ongoing efforts in the scientific community to gain meaningful insights into genomic function. Within the framework of the critical assessment of genome interpretation experiments, we participated in the Vex-seq challenge, which required predicting the change in the percent spliced in measure (ΔΨ) for 58 exons caused by more than 1,000 genomic variants. Experimentally determined through the Vex-seq assay, the Ψ quantifies the fraction of reads that include an exon of interest. Predicting the change in Ψ associated with specific genomic variants implies determining the sequence changes relevant for splicing regulators, such as splicing enhancers and silencers. Here we took advantage of two computational tools, SplicePort and SPANR, that incorporate relevant sequence features in their models of splice sites and exon-inclusion level, respectively. Specifically, we used the SplicePort and SPANR outputs to build mathematical models of the experimental data obtained for the variants in the training set, which we then used to predict the ΔΨ associated with the mutations in the test set. We show that the sequence changes captured by these computational tools provide a reasonable foundation for modeling the impact on splicing associated with genomic variants.
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Affiliation(s)
- Valer Gotea
- Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Gennady Margolin
- Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Laura Elnitski
- Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
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7
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D'Aquila P, Crocco P, De Rango F, Indiveri C, Bellizzi D, Rose G, Passarino G. A Genetic Variant of ASCT2 Hampers In Vitro RNA Splicing and Correlates with Human Longevity. Rejuvenation Res 2018; 21:193-199. [DOI: 10.1089/rej.2017.1948] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Patrizia D'Aquila
- Department of Biology, Ecology and Earth Science, University of Calabria, Rende, Italy
| | - Paolina Crocco
- Department of Biology, Ecology and Earth Science, University of Calabria, Rende, Italy
| | - Francesco De Rango
- Department of Biology, Ecology and Earth Science, University of Calabria, Rende, Italy
| | - Cesare Indiveri
- Department of Biology, Ecology and Earth Science, University of Calabria, Rende, Italy
| | - Dina Bellizzi
- Department of Biology, Ecology and Earth Science, University of Calabria, Rende, Italy
| | - Giuseppina Rose
- Department of Biology, Ecology and Earth Science, University of Calabria, Rende, Italy
| | - Giuseppe Passarino
- Department of Biology, Ecology and Earth Science, University of Calabria, Rende, Italy
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8
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regSNPs-splicing: a tool for prioritizing synonymous single-nucleotide substitution. Hum Genet 2017; 136:1279-1289. [PMID: 28391525 PMCID: PMC5602096 DOI: 10.1007/s00439-017-1783-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 02/27/2017] [Indexed: 02/06/2023]
Abstract
While synonymous single-nucleotide variants (sSNVs) have largely been unstudied, since they do not alter protein sequence, mounting evidence suggests that they may affect RNA conformation, splicing, and the stability of nascent-mRNAs to promote various diseases. Accurately prioritizing deleterious sSNVs from a pool of neutral ones can significantly improve our ability of selecting functional genetic variants identified from various genome-sequencing projects, and, therefore, advance our understanding of disease etiology. In this study, we develop a computational algorithm to prioritize sSNVs based on their impact on mRNA splicing and protein function. In addition to genomic features that potentially affect splicing regulation, our proposed algorithm also includes dozens structural features that characterize the functions of alternatively spliced exons on protein function. Our systematical evaluation on thousands of sSNVs suggests that several structural features, including intrinsic disorder protein scores, solvent accessible surface areas, protein secondary structures, and known and predicted protein family domains, show significant differences between disease-causing and neutral sSNVs. Our result suggests that the protein structure features offer an added dimension of information while distinguishing disease-causing and neutral synonymous variants. The inclusion of structural features increases the predictive accuracy for functional sSNV prioritization.
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9
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Gotea V, Gartner JJ, Qutob N, Elnitski L, Samuels Y. The functional relevance of somatic synonymous mutations in melanoma and other cancers. Pigment Cell Melanoma Res 2016; 28:673-84. [PMID: 26300548 DOI: 10.1111/pcmr.12413] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 08/19/2015] [Indexed: 01/07/2023]
Abstract
Recent technological advances in sequencing have flooded the field of cancer research with knowledge about somatic mutations for many different cancer types. Most cancer genomics studies focus on mutations that alter the amino acid sequence, ignoring the potential impact of synonymous mutations. However, accumulating experimental evidence has demonstrated clear consequences for gene function, leading to a widespread recognition of the functional role of synonymous mutations and their causal connection to various diseases. Here, we review the evidence supporting the direct impact of synonymous mutations on gene function via gene splicing; mRNA stability, folding, and translation; protein folding; and miRNA-based regulation of expression. These results highlight the functional contribution of synonymous mutations to oncogenesis and the need to further investigate their detection and prioritization for experimental assessment.
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Affiliation(s)
- Valer Gotea
- Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Jared J Gartner
- Surgery Branch, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Nouar Qutob
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Laura Elnitski
- Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Yardena Samuels
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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10
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Moisan S, Berlivet S, Ka C, Le Gac G, Dostie J, Férec C. Analysis of long-range interactions in primary human cells identifies cooperative CFTR regulatory elements. Nucleic Acids Res 2015; 44:2564-76. [PMID: 26615198 PMCID: PMC4824072 DOI: 10.1093/nar/gkv1300] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 11/07/2015] [Indexed: 12/19/2022] Open
Abstract
A mechanism by which control DNA elements regulate transcription over large linear genomic distances is by achieving close physical proximity with genes, and looping of the intervening chromatin paths. Alterations of such regulatory 'chromatin looping' systems are likely to play a critical role in human genetic disease at large. Here, we studied the spatial organization of a ≈790 kb locus encompassing the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Dysregulation of CFTR is responsible for cystic fibrosis, which is the most common lethal genetic disorder in Caucasian populations. CFTR is a relatively large gene of 189 kb with a rather complex tissue-specific and temporal expression profile. We used chromatin conformation at the CFTR locus to identify new DNA sequences that regulate its transcription. By comparing 5C chromatin interaction maps of the CFTR locus in expressing and non-expressing human primary cells, we identified several new contact points between the CFTR promoter and its surroundings, in addition to regions featuring previously described regulatory elements. We demonstrate that two of these novel interacting regions cooperatively increase CFTR expression, and suggest that the new enhancer elements located on either side of the gene are brought together through chromatin looping via CTCF.
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Affiliation(s)
- Stéphanie Moisan
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Inserm U1078, Université de Brest, SFR ScInBioS, CHRU de Brest, Établissement Français du Sang - Bretagne, Brest, France
| | - Soizik Berlivet
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montréal, Québec, H3G 1Y6, Canada
| | - Chandran Ka
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Inserm U1078, Université de Brest, SFR ScInBioS, CHRU de Brest, Établissement Français du Sang - Bretagne, Brest, France
| | - Gérald Le Gac
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Inserm U1078, Université de Brest, SFR ScInBioS, CHRU de Brest, Établissement Français du Sang - Bretagne, Brest, France
| | - Josée Dostie
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montréal, Québec, H3G 1Y6, Canada
| | - Claude Férec
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Inserm U1078, Université de Brest, SFR ScInBioS, CHRU de Brest, Établissement Français du Sang - Bretagne, Brest, France
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11
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Pizzo L, Iriarte A, Alvarez-Valin F, Marín M. Conservation of CFTR codon frequency through primates suggests synonymous mutations could have a functional effect. Mutat Res 2015; 775:19-25. [PMID: 25839760 DOI: 10.1016/j.mrfmmm.2015.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 02/05/2015] [Accepted: 03/09/2015] [Indexed: 06/04/2023]
Abstract
Cystic fibrosis is an inherited chronic disease that affects the lungs and digestive system, with a prevalence of about 1:3000 people. Cystic fibrosis is caused by mutations in CFTR gene, which lead to a defective function of the chloride channel, the cystic fibrosis transmembrane conductance regulator (CFTR). Up-to-date, more than 1900 mutations have been reported in CFTR. However for an important proportion of them, their functional effects and the relation to disease are still not understood. Many of these mutations are silent (or synonymous), namely they do not alter the encoded amino acid. These synonymous mutations have been considered as neutral to protein function. However, more recent evidence in bacterial and human proteins has put this concept under revision. With the aim of understanding possible functional effects of synonymous mutations in CFTR, we analyzed human and primates CFTR codon usage and divergence patterns. We report the presence of regions enriched in rare and frequent codons. This spatial pattern of codon preferences is conserved in primates, but this cannot be explained by sequence conservation alone. In sum, the results presented herein suggest a functional implication of these regions of the gene that may be maintained by purifying selection acting to preserve a particular codon usage pattern along the sequence. Overall these results support the idea that several synonymous mutations in CFTR may have functional importance, and could be involved in the disease.
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Affiliation(s)
- Lucilla Pizzo
- Sección Bioquímica-Biología Molecular, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
| | - Andrés Iriarte
- Dpto. de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Dpto. de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, IIBCE, Montevideo, Uruguay; Dpto. de Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable, IIBCE, Montevideo, Uruguay
| | - Fernando Alvarez-Valin
- Sección Biomatemática, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Mónica Marín
- Sección Bioquímica-Biología Molecular, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
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12
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Perreault-Micale C, Davie J, Breton B, Hallam S, Greger V. A rigorous approach for selection of optimal variant sets for carrier screening with demonstration of clinical utility. Mol Genet Genomic Med 2015; 3:363-73. [PMID: 26247052 PMCID: PMC4521971 DOI: 10.1002/mgg3.148] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/24/2015] [Accepted: 03/24/2015] [Indexed: 11/29/2022] Open
Abstract
Carrier screening for certain diseases is recommended by major medical and Ashkenazi Jewish (AJ) societies. Most carrier screening panels test only for common, ethnic-specific variants. However, with formerly isolated ethnic groups becoming increasingly intermixed, this approach is becoming inadequate. Our objective was to develop a rigorous process to curate all variants, for relevant genes, into a database and then apply stringent clinical validity classification criteria to each in order to retain only those with clear evidence for pathogenicity. The resulting variant set, in conjunction with next-generation DNA sequencing (NGS), then affords the capability for an ethnically diverse, comprehensive, highly specific carrier-screening assay. The clinical utility of our approach was demonstrated by screening a pan-ethnic population of 22,864 individuals for Bloom syndrome carrier status using a BLM variant panel comprised of 50 pathogenic variants. In addition to carriers of the common AJ founder variant, we identified 57 carriers of other pathogenic BLM variants. All variants reported had previously been curated and their clinical validity documented, or were of a type that met our stringent, preassigned validity criteria. Thus, it was possible to confidently report an increased number of Bloom’s syndrome carriers compared to traditional, ethnicity-based screening, while not reducing the specificity of the screening due to reporting variants of unknown clinical significance.
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Affiliation(s)
| | - Jocelyn Davie
- Good Start Genetics, Inc. 237 Putnam Avenue, Cambridge, Massachusetts, 02139
| | - Benjamin Breton
- Good Start Genetics, Inc. 237 Putnam Avenue, Cambridge, Massachusetts, 02139
| | - Stephanie Hallam
- Good Start Genetics, Inc. 237 Putnam Avenue, Cambridge, Massachusetts, 02139
| | - Valerie Greger
- Good Start Genetics, Inc. 237 Putnam Avenue, Cambridge, Massachusetts, 02139
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13
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Sharma N, Sosnay PR, Ramalho AS, Douville C, Franca A, Gottschalk LB, Park J, Lee M, Vecchio-Pagan B, Raraigh KS, Amaral MD, Karchin R, Cutting GR. Experimental assessment of splicing variants using expression minigenes and comparison with in silico predictions. Hum Mutat 2014; 35:1249-59. [PMID: 25066652 DOI: 10.1002/humu.22624] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 07/13/2014] [Indexed: 12/28/2022]
Abstract
Assessment of the functional consequences of variants near splice sites is a major challenge in the diagnostic laboratory. To address this issue, we created expression minigenes (EMGs) to determine the RNA and protein products generated by splice site variants (n = 10) implicated in cystic fibrosis (CF). Experimental results were compared with the splicing predictions of eight in silico tools. EMGs containing the full-length Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) coding sequence and flanking intron sequences generated wild-type transcript and fully processed protein in Human Embryonic Kidney (HEK293) and CF bronchial epithelial (CFBE41o-) cells. Quantification of variant induced aberrant mRNA isoforms was concordant using fragment analysis and pyrosequencing. The splicing patterns of c.1585-1G>A and c.2657+5G>A were comparable to those reported in primary cells from individuals bearing these variants. Bioinformatics predictions were consistent with experimental results for 9/10 variants (MES), 8/10 variants (NNSplice), and 7/10 variants (SSAT and Sroogle). Programs that estimate the consequences of mis-splicing predicted 11/16 (HSF and ASSEDA) and 10/16 (Fsplice and SplicePort) experimentally observed mRNA isoforms. EMGs provide a robust experimental approach for clinical interpretation of splice site variants and refinement of in silico tools.
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Affiliation(s)
- Neeraj Sharma
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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14
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Groeneweg JA, Ummels A, Mulder M, Bikker H, van der Smagt JJ, van Mil AM, Homfray T, Post JG, Elvan A, van der Heijden JF, Houweling AC, Jongbloed JDH, Wilde AAM, van Tintelen JP, Hauer RN, Dooijes D. Functional assessment of potential splice site variants in arrhythmogenic right ventricular dysplasia/cardiomyopathy. Heart Rhythm 2014; 11:2010-7. [PMID: 25087486 DOI: 10.1016/j.hrthm.2014.07.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Indexed: 01/31/2023]
Abstract
BACKGROUND Interpretation of genetic screening results in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) often is difficult. Pathogenicity of variants with uncertain clinical significance may be predicted by software algorithms. However, functional assessment can unambiguously demonstrate the effect of such variants. OBJECTIVE The purpose of this study was to perform functional analysis of potential splice site variants in ARVD/C patients. METHODS Nine variants in desmosomal (PKP2, JUP, DSG2, DSC2) genes with potential RNA splicing effect were analyzed. The variants were found in patients who fulfilled 2010 ARVD/C Task Force Criteria (n = 7) or had suspected ARVD/C (n = 2). Total RNA was isolated from fresh blood samples and subjected to reverse transcriptase polymerase chain reaction. RESULTS An effect on splicing was predicted by software algorithms for all variants. Of the 9 variants, 5 were intronic and 4 exonic. RNA analysis showed a functional effect on mRNA splicing by exon skipping, generation of new splice sites, or activation of cryptic sites in 6 variants. All 5 intronic variants tested severely impaired splicing. Only 1 of 4 exonic potential splice site variants was shown to have a deleterious effect on splicing. The remaining 3 exonic variants had no detectable effect on splicing, and heterozygous presence in mRNA confirmed biallelic expression. CONCLUSION Six variants of uncertain clinical significance in the PKP2, JUP, and DSG2 genes showed a deleterious effect on mRNA splicing, indicating these are ARVD/C-related pathogenic splice site mutations. These results highlight the importance of functional assessment of potential splice site variants to improve patient care and facilitate cascade screening.
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Affiliation(s)
- Judith A Groeneweg
- Department of Cardiology, University Medical Center Utrecht and ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
| | - Amber Ummels
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marcel Mulder
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hennie Bikker
- Department of Medical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Jasper J van der Smagt
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anneke M van Mil
- Department of Medical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Tessa Homfray
- Department of Clinical Genetics, St. George's Hospital Medical School, London, United Kingdom
| | - Jan G Post
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Arif Elvan
- Department of Cardiology, Isala Klinieken, Zwolle, The Netherlands
| | | | - Arjan C Houweling
- Department of Medical Genetics, VU Medical Center, Amsterdam, The Netherlands
| | - Jan D H Jongbloed
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Arthur A M Wilde
- Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| | - J Peter van Tintelen
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Durrer Center for Cardiogenetic Research, Utrecht, The Netherlands
| | - Richard N Hauer
- Department of Cardiology, University Medical Center Utrecht and ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
| | - Dennis Dooijes
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands.
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15
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Defining the disease liability of variants in the cystic fibrosis transmembrane conductance regulator gene. Nat Genet 2013; 45:1160-7. [PMID: 23974870 PMCID: PMC3874936 DOI: 10.1038/ng.2745] [Citation(s) in RCA: 428] [Impact Index Per Article: 38.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 07/30/2013] [Indexed: 12/16/2022]
Abstract
Allelic heterogeneity in disease-causing genes presents a substantial challenge to the translation of genomic variation to clinical practice. Few of the almost 2,000 variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene have empirical evidence that they cause cystic fibrosis. To address this gap, we collected both genotype and phenotype data for 39,696 cystic fibrosis patients in registries and clinics in North America and Europe. Among these patients, 159 CFTR variants had an allele frequency of ≥0.01%. These variants were evaluated for both clinical severity and functional consequence with 127 (80%) meeting both clinical and functional criteria consistent with disease. Assessment of disease penetrance in 2,188 fathers of cystic fibrosis patients enabled assignment of 12 of the remaining 32 variants as neutral while the other 20 variants remained indeterminate. This study illustrates that sourcing data directly from well-phenotyped subjects can address the gap in our ability to interpret clinically-relevant genomic variation.
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