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Abood A, Mesner LD, Jeffery ED, Murali M, Lehe MD, Saquing J, Farber CR, Sheynkman GM. Long-read proteogenomics to connect disease-associated sQTLs to the protein isoform effectors of disease. Am J Hum Genet 2024; 111:1914-1931. [PMID: 39079539 PMCID: PMC11393689 DOI: 10.1016/j.ajhg.2024.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 07/01/2024] [Accepted: 07/02/2024] [Indexed: 08/07/2024] Open
Abstract
A major fraction of loci identified by genome-wide association studies (GWASs) mediate alternative splicing, but mechanistic interpretation is hindered by the technical limitations of short-read RNA sequencing (RNA-seq), which cannot directly link splicing events to full-length protein isoforms. Long-read RNA-seq represents a powerful tool to characterize transcript isoforms, and recently, infer protein isoform existence. Here, we present an approach that integrates information from GWASs, splicing quantitative trait loci (sQTLs), and PacBio long-read RNA-seq in a disease-relevant model to infer the effects of sQTLs on the ultimate protein isoform products they encode. We demonstrate the utility of our approach using bone mineral density (BMD) GWAS data. We identified 1,863 sQTLs from the Genotype-Tissue Expression (GTEx) project in 732 protein-coding genes that colocalized with BMD associations (H4PP ≥ 0.75). We generated PacBio Iso-Seq data (N = ∼22 million full-length reads) on human osteoblasts, identifying 68,326 protein-coding isoforms, of which 17,375 (25%) were unannotated. By casting the sQTLs onto protein isoforms, we connected 809 sQTLs to 2,029 protein isoforms from 441 genes expressed in osteoblasts. Overall, we found that 74 sQTLs influenced isoforms likely impacted by nonsense-mediated decay and 190 that potentially resulted in the expression of unannotated protein isoforms. Finally, we functionally validated colocalizing sQTLs in TPM2, in which siRNA-mediated knockdown in osteoblasts showed two TPM2 isoforms with opposing effects on mineralization but exhibited no effect upon knockdown of the entire gene. Our approach should be to generalize across diverse clinical traits and to provide insights into protein isoform activities modulated by GWAS loci.
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Affiliation(s)
- Abdullah Abood
- Center for Public Health Genomics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA; Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Larry D Mesner
- Center for Public Health Genomics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA; Department of Public Health Sciences, University of Virginia, Charlottesville, VA 22908, USA
| | - Erin D Jeffery
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Mayank Murali
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Micah D Lehe
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Jamie Saquing
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Charles R Farber
- Center for Public Health Genomics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA; Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA; Department of Public Health Sciences, University of Virginia, Charlottesville, VA 22908, USA.
| | - Gloria M Sheynkman
- Center for Public Health Genomics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA; Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA; UVA Comprehensive Cancer Center, University of Virginia, Charlottesville, VA, USA.
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Abood A, Mesner LD, Jeffery ED, Murali M, Lehe M, Saquing J, Farber CR, Sheynkman GM. Long-read proteogenomics to connect disease-associated sQTLs to the protein isoform effectors of disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.17.531557. [PMID: 36993769 PMCID: PMC10055087 DOI: 10.1101/2023.03.17.531557] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
A major fraction of loci identified by genome-wide association studies (GWASs) lead to alterations in alternative splicing, but interpretation of how such alterations impact proteins is hindered by the technical limitations of short-read RNA-seq, which cannot directly link splicing events to full-length transcript or protein isoforms. Long-read RNA-seq represents a powerful tool to define and quantify transcript isoforms, and recently, infer protein isoform existence. Here we present a novel approach that integrates information from GWAS, splicing QTL (sQTL), and PacBio long-read RNA-seq in a disease-relevant model to infer the effects of sQTLs on the ultimate protein isoform products they encode. We demonstrate the utility of our approach using bone mineral density (BMD) GWAS data. We identified 1,863 sQTLs from the Genotype-Tissue Expression (GTEx) project in 732 protein-coding genes which colocalized with BMD associations (H 4 PP ≥ 0.75). We generated deep coverage PacBio long-read RNA-seq data (N=∼22 million full-length reads) on human osteoblasts, identifying 68,326 protein-coding isoforms, of which 17,375 (25%) were novel. By casting the colocalized sQTLs directly onto protein isoforms, we connected 809 sQTLs to 2,029 protein isoforms from 441 genes expressed in osteoblasts. Using these data, we created one of the first proteome-scale resources defining full-length isoforms impacted by colocalized sQTLs. Overall, we found that 74 sQTLs influenced isoforms likely impacted by nonsense mediated decay (NMD) and 190 that potentially resulted in the expression of new protein isoforms. Finally, we identified colocalizing sQTLs in TPM2 for splice junctions between two mutually exclusive exons, and two different transcript termination sites, making it impossible to interpret without long-read RNA-seq data. siRNA mediated knockdown in osteoblasts showed two TPM2 isoforms with opposing effects on mineralization. We expect our approach to be widely generalizable across diverse clinical traits and accelerate system-scale analyses of protein isoform activities modulated by GWAS loci.
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Najjar D, Chikhaoui A, Zarrouk S, Azouz S, Kamoun W, Nassib N, Bouchoucha S, Yacoub-Youssef H. Combining Gene Mutation with Expression of Candidate Genes to Improve Diagnosis of Escobar Syndrome. Genes (Basel) 2022; 13:genes13101748. [PMID: 36292632 PMCID: PMC9601381 DOI: 10.3390/genes13101748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/21/2022] [Accepted: 09/22/2022] [Indexed: 11/24/2022] Open
Abstract
Escobar syndrome is a rare, autosomal recessive disorder that affects the musculoskeletal system and the skin. Mutations in the CHRNG and TPM2 genes are associated with this pathology. In this study, we conducted a clinical and genetic investigation of five patients and also explored via in silico and gene expression analysis their phenotypic variability. In detail, we identified a patient with a novel composite heterozygous variant of the CHRNG gene and two recurrent mutations in both CHRNG and TPM2 in the rest of the patients. As for the clinical particularities, we reported a list of modifier genes in a patient suffering from myopathy. Moreover, we identified decreased expression of IGF-1, which could be related to the short stature of Escobar patients, and increased expression of POLG1 specific to patients with TPM2 mutation. Through this study, we identified the genetic spectrum of Escobar syndrome in the Tunisian population, which will allow setting up genetic counseling and prenatal diagnosis for families at risk. In addition, we highlighted relevant biomarkers that could differentiate between patients with different genetic defects.
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Affiliation(s)
- Dorra Najjar
- Laboratory of Biomedical Genomics and Oncogenetics (LR16IPT05), Institut Pasteur de Tunis, Université Tunis El Manar, Tunis 1002, Tunisia
| | - Asma Chikhaoui
- Laboratory of Biomedical Genomics and Oncogenetics (LR16IPT05), Institut Pasteur de Tunis, Université Tunis El Manar, Tunis 1002, Tunisia
| | - Sinda Zarrouk
- Genomics Platform, Institut Pasteur de Tunis (IPT), Tunis-Belvédère, Tunis 1002, Tunisia
| | - Saifeddine Azouz
- Genomics Platform, Institut Pasteur de Tunis (IPT), Tunis-Belvédère, Tunis 1002, Tunisia
| | - Wafa Kamoun
- Laboratory of Biomedical Genomics and Oncogenetics (LR16IPT05), Institut Pasteur de Tunis, Université Tunis El Manar, Tunis 1002, Tunisia
| | - Nabil Nassib
- Service Orthopédie Pédiatrique, Hôpital d’Enfant Béchir Hamza, Tunis 1000, Tunisia
| | - Sami Bouchoucha
- Service Orthopédie Pédiatrique, Hôpital d’Enfant Béchir Hamza, Tunis 1000, Tunisia
| | - Houda Yacoub-Youssef
- Laboratory of Biomedical Genomics and Oncogenetics (LR16IPT05), Institut Pasteur de Tunis, Université Tunis El Manar, Tunis 1002, Tunisia
- Correspondence:
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Pollazzon M, Caraffi SG, Faccioli S, Rosato S, Fodstad H, Campos-Xavier B, Soncini E, Comitini G, Frattini D, Grimaldi T, Marinelli M, Martorana D, Percesepe A, Sassi S, Fusco C, Gargano G, Superti-Furga A, Garavelli L. Clinical and Genetic Findings in a Series of Eight Families with Arthrogryposis. Genes (Basel) 2021; 13:genes13010029. [PMID: 35052370 PMCID: PMC8774604 DOI: 10.3390/genes13010029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/15/2021] [Accepted: 12/21/2021] [Indexed: 01/05/2023] Open
Abstract
The term “arthrogryposis” is used to indicate multiple congenital contractures affecting two or more areas of the body. Arthrogryposis is the consequence of an impairment of embryofetal neuromuscular function and development. The causes of arthrogryposis are multiple, and in newborns, it is difficult to predict the molecular defect as well as the clinical evolution just based on clinical findings. We studied a consecutive series of 13 participants who had amyoplasia, distal arthrogryposis (DA), or syndromic forms of arthrogryposis with normal intellectual development and other motor abilities. The underlying pathogenic variants were identified in 11 out of 13 participants. Correlating the genotype with the clinical features indicated that prenatal findings were specific for DA; this was helpful to identify familial cases, but features were non-specific for the involved gene. Perinatal clinical findings were similar among the participants, except for amyoplasia. Dilatation of the aortic root led to the diagnosis of Loeys–Dietz syndrome (LDS) in one case. The phenotype of DA type 5D (DA5D) and Escobar syndrome became more characteristic at later ages due to more pronounced pterygia. Follow-up indicated that DA type 1 (DA1)/DA type 2B (DA2B) spectrum and LDS had a more favorable course than the other forms. Hand clenching and talipes equinovarus/rocker bottom foot showed an improvement in all participants, and adducted thumb resolved in all forms except in amyoplasia. The combination of clinical evaluation with Next Generation Sequencing (NGS) analysis in the newborn may allow for an early diagnosis and, particularly in the DAs, suggests a favorable prognosis.
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Affiliation(s)
- Marzia Pollazzon
- Medical Genetics Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy; (M.P.); (S.G.C.); (S.R.); (M.M.)
| | - Stefano Giuseppe Caraffi
- Medical Genetics Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy; (M.P.); (S.G.C.); (S.R.); (M.M.)
| | - Silvia Faccioli
- Rehabilitation Pediatric Unit, Azienda USL-IRCCS of Reggio Emilia, 42123 Reggio Emilia, Italy; (S.F.); (S.S.)
- PhD Program in Clinical and Experimental Medicine, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Simonetta Rosato
- Medical Genetics Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy; (M.P.); (S.G.C.); (S.R.); (M.M.)
| | - Heidi Fodstad
- Division of Genetic Medicine, Lausanne University Hospital (CHUV), University of Lausanne, 1011 Lausanne, Switzerland; (H.F.); (B.C.-X.); (A.S.-F.)
| | - Belinda Campos-Xavier
- Division of Genetic Medicine, Lausanne University Hospital (CHUV), University of Lausanne, 1011 Lausanne, Switzerland; (H.F.); (B.C.-X.); (A.S.-F.)
| | - Emanuele Soncini
- Department of Obstetrics & Gynaecology, Ospedale di Sassuolo, 41049 Sassuolo, Italy;
| | - Giuseppina Comitini
- Department of Obstetrics & Gynaecology, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy;
| | - Daniele Frattini
- Child Neurology and Psychiatry Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy; (D.F.); (C.F.)
| | - Teresa Grimaldi
- Department of Cardiology, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy;
| | - Maria Marinelli
- Medical Genetics Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy; (M.P.); (S.G.C.); (S.R.); (M.M.)
| | - Davide Martorana
- Medical Genetics, Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy; (D.M.); (A.P.)
| | - Antonio Percesepe
- Medical Genetics, Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy; (D.M.); (A.P.)
| | - Silvia Sassi
- Rehabilitation Pediatric Unit, Azienda USL-IRCCS of Reggio Emilia, 42123 Reggio Emilia, Italy; (S.F.); (S.S.)
| | - Carlo Fusco
- Child Neurology and Psychiatry Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy; (D.F.); (C.F.)
| | - Giancarlo Gargano
- Neonatal Intensive Care Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy;
| | - Andrea Superti-Furga
- Division of Genetic Medicine, Lausanne University Hospital (CHUV), University of Lausanne, 1011 Lausanne, Switzerland; (H.F.); (B.C.-X.); (A.S.-F.)
| | - Livia Garavelli
- Medical Genetics Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy; (M.P.); (S.G.C.); (S.R.); (M.M.)
- Correspondence: ; Tel.: +39-0522-296244
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