1
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Cha JH, Lee SH, Yun Y, Choi WH, Koo H, Jung SH, Chae HB, Lee DH, Lee SJ, Jo DH, Kim JH, Song JJ, Chae JH, Lee JH, Park J, Kang JY, Bae S, Lee SY. Discovery of novel disease-causing mutation in SSBP1 and its correction using adenine base editor to improve mitochondrial function. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102257. [PMID: 39104869 PMCID: PMC11299580 DOI: 10.1016/j.omtn.2024.102257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 06/14/2024] [Indexed: 08/07/2024]
Abstract
Mutations in nuclear genes regulating mitochondrial DNA (mtDNA) replication are associated with mtDNA depletion syndromes. Using whole-genome sequencing, we identified a heterozygous mutation (c.272G>A:p.Arg91Gln) in single-stranded DNA-binding protein 1 (SSBP1), a crucial protein involved in mtDNA replisome. The proband manifested symptoms including sensorineural deafness, congenital cataract, optic atrophy, macular dystrophy, and myopathy. This mutation impeded multimer formation and DNA-binding affinity, leading to reduced efficiency of mtDNA replication, altered mitochondria dynamics, and compromised mitochondrial function. To correct this mutation, we tested two adenine base editor (ABE) variants on patient-derived fibroblasts. One variant, NG-Cas9-based ABE8e (NG-ABE8e), showed higher editing efficacy (≤30%) and enhanced mitochondrial replication and function, despite off-target editing frequencies; however, risks from bystander editing were limited due to silent mutations and off-target sites in non-translated regions. The other variant, NG-Cas9-based ABE8eWQ (NG-ABE8eWQ), had a safer therapeutic profile with very few off-target effects, but this came at the cost of lower editing efficacy (≤10% editing). Despite this, NG-ABE8eWQ-edited cells still restored replication and improved mtDNA copy number, which in turn recovery of compromised mitochondrial function. Taken together, base editing-based gene therapies may be a promising treatment for mitochondrial diseases, including those associated with SSBP1 mutations.
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Affiliation(s)
- Ju Hyuen Cha
- Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Seok-Hoon Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yejin Yun
- Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Won Hoon Choi
- Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Hansol Koo
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sung Ho Jung
- Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Ho Byung Chae
- Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | | | - Seok Jae Lee
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Dong Hyun Jo
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jeong Hun Kim
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jae-Jin Song
- Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Jong-Hee Chae
- Department of Genomic Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jun Ho Lee
- Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jiho Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Jin Young Kang
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Sangsu Bae
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
- Medical Research Center of Genomic Medicine Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sang-Yeon Lee
- Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Genomic Medicine, Seoul National University Hospital, Seoul, Republic of Korea
- Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea
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2
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Riccio AA, Bouvette J, Pedersen LC, Somai S, Dutcher RC, Borgnia MJ, Copeland WC. Structures of the mitochondrial single-stranded DNA binding protein with DNA and DNA polymerase γ. Nucleic Acids Res 2024:gkae670. [PMID: 39106165 DOI: 10.1093/nar/gkae670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 07/11/2024] [Accepted: 07/22/2024] [Indexed: 08/09/2024] Open
Abstract
The mitochondrial single-stranded DNA (ssDNA) binding protein, mtSSB or SSBP1, binds to ssDNA to prevent secondary structures of DNA that could impede downstream replication or repair processes. Clinical mutations in the SSBP1 gene have been linked to a range of mitochondrial disorders affecting nearly all organs and systems. Yet, the molecular determinants governing the interaction between mtSSB and ssDNA have remained elusive. Similarly, the structural interaction between mtSSB and other replisome components, such as the mitochondrial DNA polymerase, Polγ, has been minimally explored. Here, we determined a 1.9-Å X-ray crystallography structure of the human mtSSB bound to ssDNA. This structure uncovered two distinct DNA binding sites, a low-affinity site and a high-affinity site, confirmed through site-directed mutagenesis. The high-affinity binding site encompasses a clinically relevant residue, R38, and a highly conserved DNA base stacking residue, W84. Employing cryo-electron microscopy, we confirmed the tetrameric assembly in solution and capture its interaction with Polγ. Finally, we derived a model depicting modes of ssDNA wrapping around mtSSB and a region within Polγ that mtSSB binds.
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Affiliation(s)
- Amanda A Riccio
- Mitochondrial DNA Replication Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Jonathan Bouvette
- Molecular Microscopy Consortium, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Lars C Pedersen
- Structure Function Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Shruti Somai
- Mitochondrial DNA Replication Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Robert C Dutcher
- Macromolecular Structure Group, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Mario J Borgnia
- Molecular Microscopy Consortium, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - William C Copeland
- Mitochondrial DNA Replication Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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3
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Martucci M, Moretton A, Tarrés-Solé A, Ropars V, Lambert L, Vernet P, Solà M, Falkenberg M, Farge G, van den Wildenberg S. The mutation R107Q alters mtSSB ssDNA compaction ability and binding dynamics. Nucleic Acids Res 2024; 52:5912-5927. [PMID: 38742632 PMCID: PMC11162770 DOI: 10.1093/nar/gkae354] [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: 12/02/2023] [Revised: 04/02/2024] [Accepted: 04/22/2024] [Indexed: 05/16/2024] Open
Abstract
Mitochondrial single-stranded DNA-binding protein (mtSSB) is essential for mitochondrial DNA (mtDNA) replication. Recently, several mtSSB variants have been associated with autosomal dominant mitochondrial optic atrophy and retinal dystrophy. Here, we have studied at the molecular level the functional consequences of one of the most severe mtSSB variants, R107Q. We first studied the oligomeric state of this variant and observed that the mtSSBR107Q mutant forms stable tetramers in vitro. On the other hand, we showed, using complementary single-molecule approaches, that mtSSBR107Q displays a lower intramolecular ssDNA compaction ability and a higher ssDNA dissociation rate than the WT protein. Real-time competition experiments for ssDNA-binding showed a marked advantage of mtSSBWT over mtSSBR107Q. Combined, these results show that the R107Q mutation significantly impaired the ssDNA-binding and compacting ability of mtSSB, likely by weakening mtSSB ssDNA wrapping efficiency. These features are in line with our molecular modeling of ssDNA on mtSSB showing that the R107Q mutation may destabilize local interactions and results in an electronegative spot that interrupts an ssDNA-interacting-electropositive patch, thus reducing the potential mtSSB-ssDNA interaction sites.
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Affiliation(s)
- Martial Martucci
- Université Clermont Auvergne, CNRS, Laboratoire de Physique de Clermont, F-63000 Clermont-Ferrand, France
| | - Amandine Moretton
- Université Clermont Auvergne, CNRS, Laboratoire de Physique de Clermont, F-63000 Clermont-Ferrand, France
| | - Aleix Tarrés-Solé
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
| | - Virginie Ropars
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Louise Lambert
- Université Clermont Auvergne, CNRS, Laboratoire de Physique de Clermont, F-63000 Clermont-Ferrand, France
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Patrick Vernet
- Université Clermont Auvergne, CNRS, Laboratoire de Physique de Clermont, F-63000 Clermont-Ferrand, France
| | - Maria Solà
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Geraldine Farge
- Université Clermont Auvergne, CNRS, Laboratoire de Physique de Clermont, F-63000 Clermont-Ferrand, France
| | - Siet van den Wildenberg
- Université Clermont Auvergne, CNRS, Laboratoire de Physique de Clermont, F-63000 Clermont-Ferrand, France
- Université Clermont Auvergne, CNRS, IRD, Université Jean Monnet Saint Etienne, LMV, F-63000 Clermont-Ferrand, France
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4
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Ray D, Laverty KU, Jolma A, Nie K, Samson R, Pour SE, Tam CL, von Krosigk N, Nabeel-Shah S, Albu M, Zheng H, Perron G, Lee H, Najafabadi H, Blencowe B, Greenblatt J, Morris Q, Hughes TR. RNA-binding proteins that lack canonical RNA-binding domains are rarely sequence-specific. Sci Rep 2023; 13:5238. [PMID: 37002329 PMCID: PMC10066285 DOI: 10.1038/s41598-023-32245-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 03/23/2023] [Indexed: 04/03/2023] Open
Abstract
Thousands of RNA-binding proteins (RBPs) crosslink to cellular mRNA. Among these are numerous unconventional RBPs (ucRBPs)-proteins that associate with RNA but lack known RNA-binding domains (RBDs). The vast majority of ucRBPs have uncharacterized RNA-binding specificities. We analyzed 492 human ucRBPs for intrinsic RNA-binding in vitro and identified 23 that bind specific RNA sequences. Most (17/23), including 8 ribosomal proteins, were previously associated with RNA-related function. We identified the RBDs responsible for sequence-specific RNA-binding for several of these 23 ucRBPs and surveyed whether corresponding domains from homologous proteins also display RNA sequence specificity. CCHC-zf domains from seven human proteins recognized specific RNA motifs, indicating that this is a major class of RBD. For Nudix, HABP4, TPR, RanBP2-zf, and L7Ae domains, however, only isolated members or closely related homologs yielded motifs, consistent with RNA-binding as a derived function. The lack of sequence specificity for most ucRBPs is striking, and we suggest that many may function analogously to chromatin factors, which often crosslink efficiently to cellular DNA, presumably via indirect recruitment. Finally, we show that ucRBPs tend to be highly abundant proteins and suggest their identification in RNA interactome capture studies could also result from weak nonspecific interactions with RNA.
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Affiliation(s)
- Debashish Ray
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Kaitlin U Laverty
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Arttu Jolma
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Kate Nie
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Reuben Samson
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Sara E Pour
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Cyrus L Tam
- Computational and Systems Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Tri-Institutional Training Program in Computational Biology and Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Niklas von Krosigk
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Syed Nabeel-Shah
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Mihai Albu
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Hong Zheng
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Gabrielle Perron
- Department of Human Genetics, McGill University, Montréal, QC, H3A 0C7, Canada
- McGill Genome Centre, Montréal, QC, H3A 0G1, Canada
| | - Hyunmin Lee
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Hamed Najafabadi
- Department of Human Genetics, McGill University, Montréal, QC, H3A 0C7, Canada
- McGill Genome Centre, Montréal, QC, H3A 0G1, Canada
| | - Benjamin Blencowe
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jack Greenblatt
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Quaid Morris
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Computational and Systems Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Tri-Institutional Training Program in Computational Biology and Medicine, Weill Cornell Medicine, New York, NY, USA.
| | - Timothy R Hughes
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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5
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Tragni V, Primiano G, Tummolo A, Cafferati Beltrame L, La Piana G, Sgobba MN, Cavalluzzi MM, Paterno G, Gorgoglione R, Volpicella M, Guerra L, Marzulli D, Servidei S, De Grassi A, Petrosillo G, Lentini G, Pierri CL. Personalized Medicine in Mitochondrial Health and Disease: Molecular Basis of Therapeutic Approaches Based on Nutritional Supplements and Their Analogs. Molecules 2022; 27:3494. [PMID: 35684429 PMCID: PMC9182050 DOI: 10.3390/molecules27113494] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial diseases (MDs) may result from mutations affecting nuclear or mitochondrial genes, encoding mitochondrial proteins, or non-protein-coding mitochondrial RNA. Despite the great variability of affected genes, in the most severe cases, a neuromuscular and neurodegenerative phenotype is observed, and no specific therapy exists for a complete recovery from the disease. The most used treatments are symptomatic and based on the administration of antioxidant cocktails combined with antiepileptic/antipsychotic drugs and supportive therapy for multiorgan involvement. Nevertheless, the real utility of antioxidant cocktail treatments for patients affected by MDs still needs to be scientifically demonstrated. Unfortunately, clinical trials for antioxidant therapies using α-tocopherol, ascorbate, glutathione, riboflavin, niacin, acetyl-carnitine and coenzyme Q have met a limited success. Indeed, it would be expected that the employed antioxidants can only be effective if they are able to target the specific mechanism, i.e., involving the central and peripheral nervous system, responsible for the clinical manifestations of the disease. Noteworthily, very often the phenotypes characterizing MD patients are associated with mutations in proteins whose function does not depend on specific cofactors. Conversely, the administration of the antioxidant cocktails might determine the suppression of endogenous oxidants resulting in deleterious effects on cell viability and/or toxicity for patients. In order to avoid toxicity effects and before administering the antioxidant therapy, it might be useful to ascertain the blood serum levels of antioxidants and cofactors to be administered in MD patients. It would be also worthwhile to check the localization of mutations affecting proteins whose function should depend (less or more directly) on the cofactors to be administered, for estimating the real need and predicting the success of the proposed cofactor/antioxidant-based therapy.
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Affiliation(s)
- Vincenzo Tragni
- Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari Aldo Moro, Via E. Orabona, 4, 70125 Bari, Italy; (V.T.); (L.C.B.); (G.L.P.); (M.N.S.); (R.G.); (M.V.); (L.G.); (A.D.G.)
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), 70126 Bari, Italy;
| | - Guido Primiano
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (G.P.); (S.S.)
- Dipartimento Universitario di Neuroscienze, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Albina Tummolo
- Department of Metabolic Diseases, Clinical Genetics and Diabetology, Giovanni XXIII Children Hospital, Azienda Ospedaliero-Universitaria Consorziale, Via Amendola 207, 70126 Bari, Italy; (A.T.); (G.P.)
| | - Lucas Cafferati Beltrame
- Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari Aldo Moro, Via E. Orabona, 4, 70125 Bari, Italy; (V.T.); (L.C.B.); (G.L.P.); (M.N.S.); (R.G.); (M.V.); (L.G.); (A.D.G.)
| | - Gianluigi La Piana
- Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari Aldo Moro, Via E. Orabona, 4, 70125 Bari, Italy; (V.T.); (L.C.B.); (G.L.P.); (M.N.S.); (R.G.); (M.V.); (L.G.); (A.D.G.)
| | - Maria Noemi Sgobba
- Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari Aldo Moro, Via E. Orabona, 4, 70125 Bari, Italy; (V.T.); (L.C.B.); (G.L.P.); (M.N.S.); (R.G.); (M.V.); (L.G.); (A.D.G.)
| | - Maria Maddalena Cavalluzzi
- Department of Pharmacy—Pharmaceutical Sciences, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy;
| | - Giulia Paterno
- Department of Metabolic Diseases, Clinical Genetics and Diabetology, Giovanni XXIII Children Hospital, Azienda Ospedaliero-Universitaria Consorziale, Via Amendola 207, 70126 Bari, Italy; (A.T.); (G.P.)
| | - Ruggiero Gorgoglione
- Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari Aldo Moro, Via E. Orabona, 4, 70125 Bari, Italy; (V.T.); (L.C.B.); (G.L.P.); (M.N.S.); (R.G.); (M.V.); (L.G.); (A.D.G.)
| | - Mariateresa Volpicella
- Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari Aldo Moro, Via E. Orabona, 4, 70125 Bari, Italy; (V.T.); (L.C.B.); (G.L.P.); (M.N.S.); (R.G.); (M.V.); (L.G.); (A.D.G.)
| | - Lorenzo Guerra
- Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari Aldo Moro, Via E. Orabona, 4, 70125 Bari, Italy; (V.T.); (L.C.B.); (G.L.P.); (M.N.S.); (R.G.); (M.V.); (L.G.); (A.D.G.)
| | - Domenico Marzulli
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), 70126 Bari, Italy;
| | - Serenella Servidei
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (G.P.); (S.S.)
- Dipartimento Universitario di Neuroscienze, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Anna De Grassi
- Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari Aldo Moro, Via E. Orabona, 4, 70125 Bari, Italy; (V.T.); (L.C.B.); (G.L.P.); (M.N.S.); (R.G.); (M.V.); (L.G.); (A.D.G.)
| | - Giuseppe Petrosillo
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), 70126 Bari, Italy;
| | - Giovanni Lentini
- Department of Pharmacy—Pharmaceutical Sciences, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy;
| | - Ciro Leonardo Pierri
- Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari Aldo Moro, Via E. Orabona, 4, 70125 Bari, Italy; (V.T.); (L.C.B.); (G.L.P.); (M.N.S.); (R.G.); (M.V.); (L.G.); (A.D.G.)
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6
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Jurkute N, D'Esposito F, Robson AG, Pitceathly RDS, Cordeiro F, Raymond FL, Moore AT, Michaelides M, Yu-Wai-Man P, Webster AR, Arno G. SSBP1-Disease Update: Expanding the Genetic and Clinical Spectrum, Reporting Variable Penetrance and Confirming Recessive Inheritance. Invest Ophthalmol Vis Sci 2021; 62:12. [PMID: 34905022 PMCID: PMC8684315 DOI: 10.1167/iovs.62.15.12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/19/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose To report novel genotypes and expand the phenotype spectrum of SSBP1-disease and explore potential disease mechanism. Methods Five families with previously unsolved optic atrophy and retinal dystrophy underwent whole genome sequencing as part of the National Institute for Health Research BioResource Rare-Diseases and the UK's 100,000 Genomes Project. In silico analysis and protein modelling was performed on the identified variants. Deep phenotyping including retinal imaging and International Society for Clinical Electrophysiology of Vision standard visual electrophysiology was performed. Results Seven individuals from five unrelated families with bilateral optic atrophy and/or retinal dystrophy with extraocular signs and symptoms in some are described. In total, 6 SSBP1 variants were identified including the previously unreported variants: c.151A>G, p.(Lys51Glu), c.335G>A p.(Gly112Glu), and c.380G>A, p.(Arg127Gln). One individual was found to carry biallelic variants (c.380G>A p.(Arg127Gln); c.394A>G p.(Ile132Val)) associated with likely autosomal recessive SSBP1-disease. In silico analysis predicted all variants to be pathogenic and Three-dimensional protein modelling suggested possible disease mechanisms via decreased single-stranded DNA binding affinity or impaired higher structure formation. Conclusions SSBP1 is essential for mitochondrial DNA replication and maintenance, with defects leading to a spectrum of disease that includes optic atrophy and/or retinal dystrophy, occurring with or without extraocular features. This study provides evidence of intrafamilial variability and confirms the existence of an autosomal recessive inheritance in SSBP1-disease consequent upon a previously unreported genotype.
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Affiliation(s)
- Neringa Jurkute
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Fabiana D'Esposito
- Imperial College Ophthalmic Research Unit, Western Eye Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom
- Eye Clinic, Department of Neurosciences, Reproductive Sciences and Dentistry, Federico II University, Naples, Italy
| | - Anthony G. Robson
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Robert D. S. Pitceathly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Francesca Cordeiro
- Imperial College Ophthalmic Research Unit, Western Eye Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - F. Lucy Raymond
- NIHR BioResource - Rare Diseases, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Anthony T. Moore
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Michel Michaelides
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Patrick Yu-Wai-Man
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
- Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, United Kingdom
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Andrew R. Webster
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Gavin Arno
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
- North Thames Genomic Laboratory Hub, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - for the Genomics England Research Consortium
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
- Imperial College Ophthalmic Research Unit, Western Eye Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom
- Eye Clinic, Department of Neurosciences, Reproductive Sciences and Dentistry, Federico II University, Naples, Italy
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, United Kingdom
- NIHR BioResource - Rare Diseases, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
- Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, United Kingdom
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
- North Thames Genomic Laboratory Hub, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
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