1
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Stewart GS. DONSON: Slding in 2 the limelight. DNA Repair (Amst) 2024; 134:103616. [PMID: 38159447 DOI: 10.1016/j.dnarep.2023.103616] [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: 08/25/2023] [Revised: 11/18/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024]
Abstract
For over a decade, it has been known that yeast Sld2, Dpb11, GINS and Polε form the pre-loading complex (pre-LC), which is recruited to a CDC45-bound MCM2-7 complex by the Sld3/Sld7 heterodimer in a phospho-dependent manner. Whilst functional orthologs of Dbp11 (TOPBP1), Sld3 (TICRR) and Sld7 (MTBP) have been identified in metazoans, controversy has surrounded the identity of the Sld2 ortholog. It was originally proposed that the RECQ helicase, RECQL4, which is mutated in Rothmund-Thomson syndrome, represented the closest vertebrate ortholog of Sld2 due to a small region of sequence homology at its N-Terminus. However, there is no clear evidence that RECQL4 is required for CMG loading. Recently, new findings suggest that the functional ortholog of Sld2 is actually DONSON, a replication fork stability factor mutated in a range of neurodevelopmental disorders characterised by microcephaly, short stature and limb abnormalities. These studies show that DONSON forms a complex with TOPBP1, GINS and Polε analogous to the pre-LC in yeast, which is required to position the GINS complex on the MCM complex and initiate DNA replication. Taken together with previously published functions for DONSON, these observations indicate that DONSON plays two roles in regulating DNA replication, one in promoting replication initiation and one in stabilising the fork during elongation. Combined, these findings may help to uncover why DONSON mutations are associated with such a wide range of clinical deficits.
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Affiliation(s)
- Grant S Stewart
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
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2
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Mannino MC, Cassidy MB, Florez S, Rusan Z, Chakraborty S, Schoborg T. Mutations in abnormal spindle disrupt temporal transcription factor expression and trigger immune responses in the Drosophila brain. Genetics 2023; 225:iyad188. [PMID: 37831641 PMCID: PMC10697820 DOI: 10.1093/genetics/iyad188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 08/30/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023] Open
Abstract
The coordination of cellular behaviors during neurodevelopment is critical for determining the form, function, and size of the central nervous system (CNS). Mutations in the vertebrate Abnormal Spindle-Like, Microcephaly Associated (ASPM) gene and its Drosophila melanogaster ortholog abnormal spindle (asp) lead to microcephaly (MCPH), a reduction in overall brain size whose etiology remains poorly defined. Here, we provide the neurodevelopmental transcriptional landscape for a Drosophila model for autosomal recessive primary microcephaly-5 (MCPH5) and extend our findings into the functional realm to identify the key cellular mechanisms responsible for Asp-dependent brain growth and development. We identify multiple transcriptomic signatures, including new patterns of coexpressed genes in the developing CNS. Defects in optic lobe neurogenesis were detected in larval brains through downregulation of temporal transcription factors (tTFs) and Notch signaling targets, which correlated with a significant reduction in brain size and total cell numbers during the neurogenic window of development. We also found inflammation as a hallmark of asp mutant brains, detectable throughout every stage of CNS development, which also contributes to the brain size phenotype. Finally, we show that apoptosis is not a primary driver of the asp mutant brain phenotypes, further highlighting an intrinsic Asp-dependent neurogenesis promotion mechanism that is independent of cell death. Collectively, our results suggest that the etiology of the asp mutant brain phenotype is complex and that a comprehensive view of the cellular basis of the disorder requires an understanding of how multiple pathway inputs collectively determine tissue size and architecture.
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Affiliation(s)
- Maria C Mannino
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | | | - Steven Florez
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Zeid Rusan
- Personalis, Inc., Fremont, CA 94555, USA
| | - Shalini Chakraborty
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Todd Schoborg
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
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3
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Evrin C, Alvarez V, Ainsworth J, Fujisawa R, Alabert C, Labib KPM. DONSON is required for CMG helicase assembly in the mammalian cell cycle. EMBO Rep 2023; 24:e57677. [PMID: 37781960 PMCID: PMC10626419 DOI: 10.15252/embr.202357677] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/15/2023] [Accepted: 09/19/2023] [Indexed: 10/03/2023] Open
Abstract
DONSON is one of 13 genes mutated in a form of primordial microcephalic dwarfism known as Meier-Gorlin syndrome. The other 12 encode components of the CDC45-MCM-GINS helicase, around which the eukaryotic replisome forms, or are factors required for helicase assembly during DNA replication initiation. A role for DONSON in CDC45-MCM-GINS assembly was unanticipated, since DNA replication initiation can be reconstituted in vitro with purified proteins from budding yeast, which lacks DONSON. Using mouse embryonic stem cells as a model for the mammalian helicase, we show that DONSON binds directly but transiently to CDC45-MCM-GINS during S-phase and is essential for chromosome duplication. Rapid depletion of DONSON leads to the disappearance of the CDC45-MCM-GINS helicase from S-phase cells and our data indicate that DONSON is dispensable for loading of the MCM2-7 helicase core onto chromatin during G1-phase, but instead is essential for CDC45-MCM-GINS assembly during S-phase. These data identify DONSON as a missing link in our understanding of mammalian chromosome duplication and provide a molecular explanation for why mutations in human DONSON are associated with Meier-Gorlin syndrome.
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Affiliation(s)
- Cecile Evrin
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Vanesa Alvarez
- Division of Molecular, Cell & Developmental Biology, School of Life SciencesUniversity of DundeeDundeeUK
| | - Johanna Ainsworth
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Ryo Fujisawa
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Constance Alabert
- Division of Molecular, Cell & Developmental Biology, School of Life SciencesUniversity of DundeeDundeeUK
| | - Karim PM Labib
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
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4
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Lim Y, Tamayo-Orrego L, Schmid E, Tarnauskaite Z, Kochenova OV, Gruar R, Muramatsu S, Lynch L, Schlie AV, Carroll PL, Chistol G, Reijns MAM, Kanemaki MT, Jackson AP, Walter JC. In silico protein interaction screening uncovers DONSON's role in replication initiation. Science 2023; 381:eadi3448. [PMID: 37590370 PMCID: PMC10801813 DOI: 10.1126/science.adi3448] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/08/2023] [Indexed: 08/19/2023]
Abstract
CDC45-MCM2-7-GINS (CMG) helicase assembly is the central event in eukaryotic replication initiation. In yeast, a multi-subunit "pre-loading complex" (pre-LC) accompanies GINS to chromatin-bound MCM2-7, leading to CMG formation. Here, we report that DONSON, a metazoan protein mutated in microcephalic primordial dwarfism, is required for CMG assembly in vertebrates. Using AlphaFold to screen for protein-protein interactions followed by experimental validation, we show that DONSON scaffolds a vertebrate pre-LC containing GINS, TOPBP1, and DNA pol ε. Our evidence suggests that DONSON docks the pre-LC onto MCM2-7, delivering GINS to its binding site in CMG. A patient-derived DONSON mutation compromises CMG assembly and recapitulates microcephalic dwarfism in mice. These results unify our understanding of eukaryotic replication initiation, implicate defective CMG assembly in microcephalic dwarfism, and illustrate how in silico protein-protein interaction screening accelerates mechanistic discovery.
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Affiliation(s)
- Yang Lim
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
| | - Lukas Tamayo-Orrego
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Ernst Schmid
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
| | - Zygimante Tarnauskaite
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Olga V. Kochenova
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
- Howard Hughes Medical Institute; Boston, MA 02115, USA
| | - Rhian Gruar
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
| | - Sachiko Muramatsu
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS); Mishima, Shizuoka 411-8540, Japan
| | - Luke Lynch
- Biochemistry Department, Stanford School of Medicine; Stanford, CA 94305, USA
| | - Aitana Verdu Schlie
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Paula L. Carroll
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Gheorghe Chistol
- Chemical and Systems Biology Department, Stanford School of Medicine; Stanford, CA 94305, USA
| | - Martin A. M. Reijns
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Masato T. Kanemaki
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS); Mishima, Shizuoka 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI; Mishima, Shizuoka 411-8540, Japan
- Department of Biological Science, The University of Tokyo; Tokyo 113-0033, Japan
| | - Andrew P. Jackson
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh; Edinburgh, EH4 2XU, UK
| | - Johannes C. Walter
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute; Boston, MA 02115, USA
- Howard Hughes Medical Institute; Boston, MA 02115, USA
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5
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Xia Y, Sonneville R, Jenkyn-Bedford M, Ji L, Alabert C, Hong Y, Yeeles JT, Labib KP. DNSN-1 recruits GINS for CMG helicase assembly during DNA replication initiation in Caenorhabditis elegans. Science 2023; 381:eadi4932. [PMID: 37590372 PMCID: PMC7615117 DOI: 10.1126/science.adi4932] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/07/2023] [Indexed: 08/19/2023]
Abstract
Assembly of the CMG (CDC-45-MCM-2-7-GINS) helicase is the key regulated step during eukaryotic DNA replication initiation. Until now, it was unclear whether metazoa require additional factors that are not present in yeast. In this work, we show that Caenorhabditis elegans DNSN-1, the ortholog of human DONSON, functions during helicase assembly in a complex with MUS-101/TOPBP1. DNSN-1 is required to recruit the GINS complex to chromatin, and a cryo-electron microscopy structure indicates that DNSN-1 positions GINS on the MCM-2-7 helicase motor (comprising the six MCM-2 to MCM-7 proteins), by direct binding of DNSN-1 to GINS and MCM-3, using interfaces that we show are important for initiation and essential for viability. These findings identify DNSN-1 as a missing link in our understanding of DNA replication initiation, suggesting that initiation defects underlie the human disease syndrome that results from DONSON mutations.
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Affiliation(s)
- Yisui Xia
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, U.K
| | - Remi Sonneville
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, U.K
| | | | - Liqin Ji
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Constance Alabert
- Division of Molecular, Cell & Developmental Biology, School of Life Sciences, University of Dundee, Dundee, U.K
| | - Ye Hong
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, U.K
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Joseph T.P. Yeeles
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, U.K
| | - Karim P.M. Labib
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, U.K
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6
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Hashimoto Y, Sadano K, Miyata N, Ito H, Tanaka H. Novel role of DONSON in CMG helicase assembly during vertebrate DNA replication initiation. EMBO J 2023; 42:e114131. [PMID: 37458194 PMCID: PMC10476173 DOI: 10.15252/embj.2023114131] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/27/2023] [Accepted: 06/29/2023] [Indexed: 09/05/2023] Open
Abstract
CMG (Cdc45-MCM-GINS) helicase assembly at the replication origin is the culmination of eukaryotic DNA replication initiation. This process can be reconstructed in vitro using defined factors in Saccharomyces cerevisiae; however, in vertebrates, origin-dependent CMG formation has not yet been achieved partly due to the lack of a complete set of known initiator proteins. Since a microcephaly gene product, DONSON, was reported to remodel the CMG helicase under replication stress, we analyzed its role in DNA replication using a Xenopus cell-free system. We found that DONSON was essential for the replisome assembly. In vertebrates, DONSON physically interacted with GINS and Polε via its conserved N-terminal PGY and NPF motifs, and the DONSON-GINS interaction contributed to the replisome assembly. DONSON's chromatin association during replication initiation required the pre-replicative complex, TopBP1, and kinase activities of S-CDK and DDK. Both S-CDK and DDK required DONSON to trigger replication initiation. Moreover, human DONSON could substitute for the Xenopus protein in a cell-free system. These findings indicate that vertebrate DONSON is a novel initiator protein essential for CMG helicase assembly.
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Affiliation(s)
- Yoshitami Hashimoto
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
| | - Kota Sadano
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
| | - Nene Miyata
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
| | - Haruka Ito
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
| | - Hirofumi Tanaka
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
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7
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Nielsen-Dandoroff E, Ruegg MSG, Bicknell LS. The expanding genetic and clinical landscape associated with Meier-Gorlin syndrome. Eur J Hum Genet 2023:10.1038/s41431-023-01359-z. [PMID: 37059840 PMCID: PMC10400559 DOI: 10.1038/s41431-023-01359-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/26/2023] [Accepted: 03/30/2023] [Indexed: 04/16/2023] Open
Abstract
High-throughput sequencing has become a standard first-tier approach for both diagnostics and research-based genetic testing. Consequently, this hypothesis-free testing manner has revealed the true breadth of clinical features for many established genetic disorders, including Meier-Gorlin syndrome (MGORS). Previously known as ear-patella short stature syndrome, MGORS is characterized by growth delay, microtia, and patella hypo/aplasia, as well as genital abnormalities, and breast agenesis in females. Following the initial identification of genetic causes in 2011, a total of 13 genes have been identified to date associated with MGORS. In this review, we summarise the genetic and clinical findings of each gene associated with MGORS and highlight molecular insights that have been made through studying patient variants. We note interesting observations arising across this group of genes as the number of patients has increased, such as the unusually high number of synonymous variants affecting splicing in CDC45 and a subgroup of genes that also cause craniosynostosis. We focus on the complicated molecular genetics for DONSON, where we examine potential genotype-phenotype patterns using the first 3D structural model of DONSON. The canonical role of all proteins associated with MGORS are involved in different stages of DNA replication and in addition to summarising how patient variants impact on this process, we discuss the potential contribution of non-canonical roles of these proteins to the pathophysiology of MGORS.
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Affiliation(s)
| | - Mischa S G Ruegg
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Louise S Bicknell
- Department of Biochemistry, University of Otago, Dunedin, New Zealand.
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8
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Nabavizadeh N, Bressin A, Shboul M, Moreno Traspas R, Chia PH, Bonnard C, Szenker‐Ravi E, Sarıbaş B, Beillard E, Altunoglu U, Hojati Z, Drutman S, Freier S, El‐Khateeb M, Fathallah R, Casanova J, Soror W, Arafat A, Escande‐Beillard N, Mayer A, Reversade B. A progeroid syndrome caused by a deep intronic variant in TAPT1 is revealed by RNA/SI-NET sequencing. EMBO Mol Med 2023; 15:e16478. [PMID: 36652330 PMCID: PMC9906387 DOI: 10.15252/emmm.202216478] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 01/19/2023] Open
Abstract
Exome sequencing has introduced a paradigm shift for the identification of germline variations responsible for Mendelian diseases. However, non-coding regions, which make up 98% of the genome, cannot be captured. The lack of functional annotation for intronic and intergenic variants makes RNA-seq a powerful companion diagnostic. Here, we illustrate this point by identifying six patients with a recessive Osteogenesis Imperfecta (OI) and neonatal progeria syndrome. By integrating homozygosity mapping and RNA-seq, we delineated a deep intronic TAPT1 mutation (c.1237-52 G>A) that segregated with the disease. Using SI-NET-seq, we document that TAPT1's nascent transcription was not affected in patients' fibroblasts, indicating instead that this variant leads to an alteration of pre-mRNA processing. Predicted to serve as an alternative splicing branchpoint, this mutation enhances TAPT1 exon 12 skipping, creating a protein-null allele. Additionally, our study reveals dysregulation of pathways involved in collagen and extracellular matrix biology in disease-relevant cells. Overall, our work highlights the power of transcriptomic approaches in deciphering the repercussions of non-coding variants, as well as in illuminating the molecular mechanisms of human diseases.
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Affiliation(s)
- Nasrinsadat Nabavizadeh
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
- Division of Genetics, Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and TechnologyUniversity of IsfahanIsfahanIran
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
| | | | - Mohammad Shboul
- Department of Medical Laboratory SciencesJordan University of Science and TechnologyIrbidJordan
| | - Ricardo Moreno Traspas
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
| | - Poh Hui Chia
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
| | - Carine Bonnard
- Model Development, A*STAR Skin Research Labs (A*SRL)Singapore CitySingapore
| | - Emmanuelle Szenker‐Ravi
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
| | - Burak Sarıbaş
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
| | | | - Umut Altunoglu
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
| | - Zohreh Hojati
- Division of Genetics, Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and TechnologyUniversity of IsfahanIsfahanIran
| | - Scott Drutman
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller BranchRockefeller UniversityNew YorkNYUSA
| | - Susanne Freier
- Max Planck Institute for Molecular GeneticsBerlinGermany
| | | | - Rajaa Fathallah
- National Center for Diabetes, Endocrinology and GeneticsAmmanJordan
| | - Jean‐Laurent Casanova
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller BranchRockefeller UniversityNew YorkNYUSA
- Laboratory of Human Genetics of Infectious Diseases, Necker BranchINSERM U1163, Necker Hospital for Sick ChildrenParisFrance
- Imagine InstituteUniversity of ParisParisFrance
- Howard Hughes Medical InstituteNew YorkNYUSA
- Pediatric Hematology and Immunology UnitNecker Hospital for Sick ChildrenParisFrance
| | - Wesam Soror
- National Center for Diabetes, Endocrinology and GeneticsAmmanJordan
| | - Alaa Arafat
- National Center for Diabetes, Endocrinology and GeneticsAmmanJordan
| | - Nathalie Escande‐Beillard
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
- Institute of Molecular and Cell Biology, A*STARSingapore CitySingapore
| | - Andreas Mayer
- Max Planck Institute for Molecular GeneticsBerlinGermany
| | - Bruno Reversade
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
- Institute of Molecular and Cell Biology, A*STARSingapore CitySingapore
- Department of PaediatricsNational University of SingaporeSingapore CitySingapore
- Smart‐Health Initiative, BESE, KAUSTThuwalKingdom of Saudi Arabia
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9
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Mannino MC, Bartels Cassidy M, Florez S, Rusan Z, Chakraborty S, Schoborg T. The neurodevelopmental transcriptome of the Drosophila melanogaster microcephaly gene abnormal spindle reveals a role for temporal transcription factors and the immune system in regulating brain size. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523369. [PMID: 36711768 PMCID: PMC9882087 DOI: 10.1101/2023.01.09.523369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The coordination of cellular behaviors during neurodevelopment is critical for determining the form, function, and size of the central nervous system. Mutations in the vertebrate Abnormal Spindle-Like, Microcephaly Associated (ASPM) gene and its Drosophila melanogaster ortholog abnormal spindle (asp) lead to microcephaly, a reduction in overall brain size whose etiology remains poorly defined. Here we provide the neurodevelopmental transcriptional landscape for a Drosophila model for autosomal recessive primary microcephaly (MCPH) and extend our findings into the functional realm in an attempt to identify the key cellular mechanisms responsible for Asp-dependent brain growth and development. We identify multiple transcriptomic signatures, including new patterns of co-expressed genes in the developing CNS. Defects in optic lobe neurogenesis were detected in larval brains through downregulation of temporal transcription factors (tTFs) and Notch signaling targets, which correlated with a significant reduction in brain size and total cell numbers during the neurogenic window of development. We also found inflammation as a hallmark of asp MCPH brains, detectable throughout every stage of CNS development, which also contributes to the brain size phenotype. Finally, we show that apoptosis is not a primary driver of the asp MCPH phenotype, further highlighting an intrinsic Asp-dependent neurogenesis promotion mechanism that is independent of cell death. Collectively, our results suggest that the etiology of asp MCPH is complex and that a comprehensive view of the cellular basis of the disorder requires an understanding of how multiple pathway inputs collectively determine the microcephaly phenotype.
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Affiliation(s)
- Maria C. Mannino
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | | | - Steven Florez
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | | | - Shalini Chakraborty
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Todd Schoborg
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
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10
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Nerakh G, Vineeth VS, Tallapaka K, Nair L, Dalal A, Aggarwal S. Microcephalic primordial dwarfism with predominant Meier-Gorlin phenotype, ichthyosis, and multiple joint deformities-Further expansion of DONSON Cell Cycle-opathy phenotypic spectrum. Am J Med Genet A 2022; 188:2139-2146. [PMID: 35298084 DOI: 10.1002/ajmg.a.62725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/18/2022] [Accepted: 02/26/2022] [Indexed: 11/10/2022]
Abstract
We report a patient with microcephalic primordial dwarfism with predominant Meier-Gorlin syndrome phenotype with ichthyosis and disabling multiple joint deformities in addition to classic features of the syndrome. The patient was a 10.5-year-old girl referred in view of short stature, joint deformities, and facial dysmorphism. There was history of intrauterine growth restriction and collodion like skin abnormality at birth. She had normal developmental milestones and intellect. On clinical evaluation, anthropometry was suggestive of proportionate short stature and microcephaly. There was abnormal posture due to spine and peripheral joint deformities, along with ichthyosis, facial, and digital dysmorphism. Skeletal radiographs showed radial subluxation, acetabular dysplasia and hip dislocation, bilateral knee joint dislocation, absent patellae, slender long bones with delayed bone age, and subluxation of small joints of hands and feet. Work up for metabolic bone disease and peripheral blood karyotype was normal. Whole exome sequencing revealed a pathogenic homozygous variant c.C1297T (p.Pro433Ser) in the exon 8 of DONSON gene. This report further expands the genotypic-phenotypic spectrum of the group of disorders known as Cell Cycle-opathies.
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Affiliation(s)
- Gayatri Nerakh
- Department of Medical Genetics, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India.,Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
| | - Venugopal S Vineeth
- Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
| | - Karthik Tallapaka
- Department of Medical Genetics, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India.,Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
| | - Lekshmi Nair
- Department of Medical Genetics, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India.,Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
| | - Ashwin Dalal
- Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
| | - Shagun Aggarwal
- Department of Medical Genetics, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India.,Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
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11
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Single-cell delineation of lineage and genetic identity in the mouse brain. Nature 2022; 601:404-409. [PMID: 34912118 PMCID: PMC8770128 DOI: 10.1038/s41586-021-04237-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 11/12/2021] [Indexed: 01/25/2023]
Abstract
During neurogenesis, mitotic progenitor cells lining the ventricles of the embryonic mouse brain undergo their final rounds of cell division, giving rise to a wide spectrum of postmitotic neurons and glia1,2. The link between developmental lineage and cell-type diversity remains an open question. Here we used massively parallel tagging of progenitors to track clonal relationships and transcriptomic signatures during mouse forebrain development. We quantified clonal divergence and convergence across all major cell classes postnatally, and found diverse types of GABAergic neuron that share a common lineage. Divergence of GABAergic clones occurred during embryogenesis upon cell-cycle exit, suggesting that differentiation into subtypes is initiated as a lineage-dependent process at the progenitor cell level.
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12
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Abstract
In this review, Phan et al. discuss the different models that have been proposed to explain how centrosome dysfunction impairs cortical development, and review the evidence supporting a unified model in which centrosome defects reduce cell proliferation in the developing cortex by prolonging mitosis and activating a mitotic surveillance pathway. Last, they also extend their discussion to centrosome-independent microcephaly mutations, such as those involved in DNA replication and repair Primary microcephaly is a brain growth disorder characterized by a severe reduction of brain size and thinning of the cerebral cortex. Many primary microcephaly mutations occur in genes that encode centrosome proteins, highlighting an important role for centrosomes in cortical development. Centrosomes are microtubule organizing centers that participate in several processes, including controlling polarity, catalyzing spindle assembly in mitosis, and building primary cilia. Understanding which of these processes are altered and how these disruptions contribute to microcephaly pathogenesis is a central unresolved question. In this review, we revisit the different models that have been proposed to explain how centrosome dysfunction impairs cortical development. We review the evidence supporting a unified model in which centrosome defects reduce cell proliferation in the developing cortex by prolonging mitosis and activating a mitotic surveillance pathway. Finally, we also extend our discussion to centrosome-independent microcephaly mutations, such as those involved in DNA replication and repair.
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13
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Zhang J, Bellani MA, Huang J, James RC, Pokharel D, Gichimu J, Gali H, Stewart G, Seidman MM. Replication of the Mammalian Genome by Replisomes Specific for Euchromatin and Heterochromatin. Front Cell Dev Biol 2021; 9:729265. [PMID: 34532320 PMCID: PMC8438199 DOI: 10.3389/fcell.2021.729265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/10/2021] [Indexed: 11/26/2022] Open
Abstract
Replisomes follow a schedule in which replication of DNA in euchromatin is early in S phase while sequences in heterochromatin replicate late. Impediments to DNA replication, referred to as replication stress, can stall replication forks triggering activation of the ATR kinase and downstream pathways. While there is substantial literature on the local consequences of replisome stalling-double strand breaks, reversed forks, or genomic rearrangements-there is limited understanding of the determinants of replisome stalling vs. continued progression. Although many proteins are recruited to stalled replisomes, current models assume a single species of "stressed" replisome, independent of genomic location. Here we describe our approach to visualizing replication fork encounters with the potent block imposed by a DNA interstrand crosslink (ICL) and our discovery of an unexpected pathway of replication restart (traverse) past an intact ICL. Additionally, we found two biochemically distinct replisomes distinguished by activity in different stages of S phase and chromatin environment. Each contains different proteins that contribute to ICL traverse.
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Affiliation(s)
- Jing Zhang
- Department of Neurosurgery, Institute for Advanced Study, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Marina A. Bellani
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Jing Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Institute of Chemical Biology and Nanomedicine, Hunan University, Changsha, China
| | - Ryan C. James
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, United States
| | - Durga Pokharel
- Horizon Discovery Group plc, Lafayette, CO, United States
| | - Julia Gichimu
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Himabindu Gali
- Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Grant Stewart
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Science, University of Birmingham, Birmingham, United Kingdom
| | - Michael M. Seidman
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
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14
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Mullin NK, Voigt AP, Cooke JA, Bohrer LR, Burnight ER, Stone EM, Mullins RF, Tucker BA. Patient derived stem cells for discovery and validation of novel pathogenic variants in inherited retinal disease. Prog Retin Eye Res 2021; 83:100918. [PMID: 33130253 PMCID: PMC8559964 DOI: 10.1016/j.preteyeres.2020.100918] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/22/2020] [Accepted: 10/27/2020] [Indexed: 02/07/2023]
Abstract
Our understanding of inherited retinal disease has benefited immensely from molecular genetic analysis over the past several decades. New technologies that allow for increasingly detailed examination of a patient's DNA have expanded the catalog of genes and specific variants that cause retinal disease. In turn, the identification of pathogenic variants has allowed the development of gene therapies and low-cost, clinically focused genetic testing. Despite this progress, a relatively large fraction (at least 20%) of patients with clinical features suggestive of an inherited retinal disease still do not have a molecular diagnosis today. Variants that are not obviously disruptive to the codon sequence of exons can be difficult to distinguish from the background of benign human genetic variations. Some of these variants exert their pathogenic effect not by altering the primary amino acid sequence, but by modulating gene expression, isoform splicing, or other transcript-level mechanisms. While not discoverable by DNA sequencing methods alone, these variants are excellent targets for studies of the retinal transcriptome. In this review, we present an overview of the current state of pathogenic variant discovery in retinal disease and identify some of the remaining barriers. We also explore the utility of new technologies, specifically patient-derived induced pluripotent stem cell (iPSC)-based modeling, in further expanding the catalog of disease-causing variants using transcriptome-focused methods. Finally, we outline bioinformatic analysis techniques that will allow this new method of variant discovery in retinal disease. As the knowledge gleaned from previous technologies is informing targets for therapies today, we believe that integrating new technologies, such as iPSC-based modeling, into the molecular diagnosis pipeline will enable a new wave of variant discovery and expanded treatment of inherited retinal disease.
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Affiliation(s)
- Nathaniel K Mullin
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Andrew P Voigt
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Jessica A Cooke
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Laura R Bohrer
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Erin R Burnight
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Edwin M Stone
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Robert F Mullins
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Budd A Tucker
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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15
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DNA2 in Chromosome Stability and Cell Survival-Is It All about Replication Forks? Int J Mol Sci 2021; 22:ijms22083984. [PMID: 33924313 PMCID: PMC8069077 DOI: 10.3390/ijms22083984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/08/2021] [Accepted: 04/10/2021] [Indexed: 01/16/2023] Open
Abstract
The conserved nuclease-helicase DNA2 has been linked to mitochondrial myopathy, Seckel syndrome, and cancer. Across species, the protein is indispensable for cell proliferation. On the molecular level, DNA2 has been implicated in DNA double-strand break (DSB) repair, checkpoint activation, Okazaki fragment processing (OFP), and telomere homeostasis. More recently, a critical contribution of DNA2 to the replication stress response and recovery of stalled DNA replication forks (RFs) has emerged. Here, we review the available functional and phenotypic data and propose that the major cellular defects associated with DNA2 dysfunction, and the links that exist with human disease, can be rationalized through the fundamental importance of DNA2-dependent RF recovery to genome duplication. Being a crucial player at stalled RFs, DNA2 is a promising target for anti-cancer therapy aimed at eliminating cancer cells by replication-stress overload.
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16
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Spotlight on the Replisome: Aetiology of DNA Replication-Associated Genetic Diseases. Trends Genet 2021; 37:317-336. [DOI: 10.1016/j.tig.2020.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/07/2020] [Accepted: 09/09/2020] [Indexed: 12/26/2022]
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17
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The microcephaly gene Donson is essential for progenitors of cortical glutamatergic and GABAergic neurons. PLoS Genet 2021; 17:e1009441. [PMID: 33739968 PMCID: PMC8011756 DOI: 10.1371/journal.pgen.1009441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 03/31/2021] [Accepted: 02/23/2021] [Indexed: 11/19/2022] Open
Abstract
Biallelic mutations in DONSON, an essential gene encoding for a replication fork protection factor, were linked to skeletal abnormalities and microcephaly. To better understand DONSON function in corticogenesis, we characterized Donson expression and consequences of conditional Donson deletion in the mouse telencephalon. Donson was widely expressed in the proliferation and differentiation zones of the embryonic dorsal and ventral telencephalon, which was followed by a postnatal expression decrease. Emx1-Cre-mediated Donson deletion in progenitors of cortical glutamatergic neurons caused extensive apoptosis in the early dorsomedial neuroepithelium, thus preventing formation of the neocortex and hippocampus. At the place of the missing lateral neocortex, these mutants exhibited a dorsal extension of an early-generated paleocortex. Targeting cortical neurons at the intermediate progenitor stage using Tbr2-Cre evoked no apparent malformations, whereas Nkx2.1-Cre-mediated Donson deletion in subpallial progenitors ablated 75% of Nkx2.1-derived cortical GABAergic neurons. Thus, the early telencephalic neuroepithelium depends critically on Donson function. Our findings help explain why the neocortex is most severely affected in individuals with DONSON mutations and suggest that DONSON-dependent microcephaly might be associated with so far unrecognized defects in cortical GABAergic neurons. Targeting Donson using an appropriate recombinase is proposed as a feasible strategy to ablate proliferating and nascent cells in experimental research. The cerebral cortex constitutes the largest part of the mammalian brain and is generated prenatally by highly proliferative progenitors. Genes encoding proteins that are essential for chromosomal segregation, mitotic division, DNA repair, and DNA damage response are frequently mutated in individuals diagnosed with microcephaly, a clinical condition characterized by cerebrocortical hypotrophy. Recent findings suggest that biallelic mutations in DONSON, a replication fork stabilization factor, cause microcephaly and skeletal defects, but this has not been formally tested. Here, we find that Cre-mediated Donson deletion in progenitors of cortical glutamatergic and cortical GABAergic neurons causes extensive programmed cell death at early stages of cortical development in mice. Cell death is induced in the proliferation zones and the postmitotic differentiation zones of the targeted progenitors. Mice undergoing Donson ablation in glutamatergic progenitors do not develop the hippocampus and dorsolateral neocortex, which leads to a dorsal shift of the early-generated piriform cortex. Donson deletion in GABAergic progenitors eliminates the vast majority of GABAergic neurons and oligodendrocyte precursors arising in the targeted lineage. We thus establish that Donson is essential for diverse early telencephalic progenitors. Targeting Donson might be used to kill off highly proliferating cells in experimental and probably therapeutic settings.
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18
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Cicconi A, Rai R, Xiong X, Broton C, Al-Hiyasat A, Hu C, Dong S, Sun W, Garbarino J, Bindra RS, Schildkraut C, Chen Y, Chang S. Microcephalin 1/BRIT1-TRF2 interaction promotes telomere replication and repair, linking telomere dysfunction to primary microcephaly. Nat Commun 2020; 11:5861. [PMID: 33203878 PMCID: PMC7672075 DOI: 10.1038/s41467-020-19674-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 10/22/2020] [Indexed: 01/07/2023] Open
Abstract
Telomeres protect chromosome ends from inappropriately activating the DNA damage and repair responses. Primary microcephaly is a key clinical feature of several human telomere disorder syndromes, but how microcephaly is linked to dysfunctional telomeres is not known. Here, we show that the microcephalin 1/BRCT-repeats inhibitor of hTERT (MCPH1/BRIT1) protein, mutated in primary microcephaly, specifically interacts with the TRFH domain of the telomere binding protein TRF2. The crystal structure of the MCPH1-TRF2 complex reveals that this interaction is mediated by the MCPH1 330YRLSP334 motif. TRF2-dependent recruitment of MCPH1 promotes localization of DNA damage factors and homology directed repair of dysfunctional telomeres lacking POT1-TPP1. Additionally, MCPH1 is involved in the replication stress response, promoting telomere replication fork progression and restart of stalled telomere replication forks. Our work uncovers a previously unrecognized role for MCPH1 in promoting telomere replication, providing evidence that telomere replication defects may contribute to the onset of microcephaly.
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Affiliation(s)
- Alessandro Cicconi
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Rekha Rai
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Xuexue Xiong
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Cayla Broton
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.5386.8000000041936877XTri- Institutional MD/PhD Program, Weill Cornell Medical College, New York, NY 10065 USA
| | - Amer Al-Hiyasat
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Chunyi Hu
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Siying Dong
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Wenqi Sun
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Jennifer Garbarino
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Therapeutic Radiology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Ranjit S. Bindra
- grid.47100.320000000419368710Department of Therapeutic Radiology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Experimental Pathology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Carl Schildkraut
- grid.251993.50000000121791997Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 USA
| | - Yong Chen
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Sandy Chang
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Pathology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
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19
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Jean F, Stuart A, Tarailo-Graovac M. Dissecting the Genetic and Etiological Causes of Primary Microcephaly. Front Neurol 2020; 11:570830. [PMID: 33178111 PMCID: PMC7593518 DOI: 10.3389/fneur.2020.570830] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/09/2020] [Indexed: 12/20/2022] Open
Abstract
Autosomal recessive primary microcephaly (MCPH; “small head syndrome”) is a rare, heterogeneous disease arising from the decreased production of neurons during brain development. As of August 2020, the Online Mendelian Inheritance in Man (OMIM) database lists 25 genes (involved in molecular processes such as centriole biogenesis, microtubule dynamics, spindle positioning, DNA repair, transcriptional regulation, Wnt signaling, and cell cycle checkpoints) that are implicated in causing MCPH. Many of these 25 genes were only discovered in the last 10 years following advances in exome and genome sequencing that have improved our ability to identify disease-causing variants. Despite these advances, many patients still lack a genetic diagnosis. This demonstrates a need to understand in greater detail the molecular mechanisms and genetics underlying MCPH. Here, we briefly review the molecular functions of each MCPH gene and how their loss disrupts the neurogenesis program, ultimately demonstrating that microcephaly arises from cell cycle dysregulation. We also explore the current issues in the genetic basis and clinical presentation of MCPH as additional avenues of improving gene/variant prioritization. Ultimately, we illustrate that the detailed exploration of the etiology and inheritance of MCPH improves the predictive power in identifying previously unknown MCPH candidates and diagnosing microcephalic patients.
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Affiliation(s)
- Francesca Jean
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Amanda Stuart
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Maja Tarailo-Graovac
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
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20
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Zhang J, Bellani MA, James RC, Pokharel D, Zhang Y, Reynolds JJ, McNee GS, Jackson AP, Stewart GS, Seidman MM. DONSON and FANCM associate with different replisomes distinguished by replication timing and chromatin domain. Nat Commun 2020; 11:3951. [PMID: 32769987 PMCID: PMC7414851 DOI: 10.1038/s41467-020-17449-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 06/30/2020] [Indexed: 12/11/2022] Open
Abstract
Duplication of mammalian genomes requires replisomes to overcome numerous impediments during passage through open (eu) and condensed (hetero) chromatin. Typically, studies of replication stress characterize mixed populations of challenged and unchallenged replication forks, averaged across S phase, and model a single species of “stressed” replisome. Here, in cells containing potent obstacles to replication, we find two different lesion proximal replisomes. One is bound by the DONSON protein and is more frequent in early S phase, in regions marked by euchromatin. The other interacts with the FANCM DNA translocase, is more prominent in late S phase, and favors heterochromatin. The two forms can also be detected in unstressed cells. ChIP-seq of DNA associated with DONSON or FANCM confirms the bias of the former towards regions that replicate early and the skew of the latter towards regions that replicate late. Eukaryotic replisomes are multiprotein complexes. Here the authors reveal two distinct stressed replisomes, associated with DONSON and FANCM, displaying a bias in replication timing and chromatin domain.
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Affiliation(s)
- Jing Zhang
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Marina A Bellani
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Ryan C James
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA
| | | | - Yongqing Zhang
- Gene Expression and Genomics Unit, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - John J Reynolds
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Gavin S McNee
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Andrew P Jackson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Grant S Stewart
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Michael M Seidman
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA.
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21
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Chorin O, Yachelevich N, Mohamed K, Moscatelli I, Pappas J, Henriksen K, Evrony GD. Transcriptome sequencing identifies a noncoding, deep intronic variant in CLCN7 causing autosomal recessive osteopetrosis. Mol Genet Genomic Med 2020; 8:e1405. [PMID: 32691986 PMCID: PMC7549584 DOI: 10.1002/mgg3.1405] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/16/2020] [Accepted: 06/29/2020] [Indexed: 12/15/2022] Open
Abstract
Background Over half of children with rare genetic diseases remain undiagnosed despite maximal clinical evaluation and DNA‐based genetic testing. As part of an Undiagnosed Diseases Program applying transcriptome (RNA) sequencing to identify the causes of these unsolved cases, we studied a child with severe infantile osteopetrosis leading to cranial nerve palsies, bone deformities, and bone marrow failure, for whom whole‐genome sequencing was nondiagnostic. Methods We performed transcriptome (RNA) sequencing of whole blood followed by analysis of aberrant transcript isoforms and osteoclast functional studies. Results We identified a pathogenic deep intronic variant in CLCN7 creating an unexpected, frameshifting pseudoexon causing complete loss of function. Functional studies, including osteoclastogenesis and bone resorption assays, confirmed normal osteoclast differentiation but loss of osteoclast function. Conclusion This is the first report of a pathogenic deep intronic variant in CLCN7, and our approach provides a model for systematic identification of noncoding variants causing osteopetrosis—a disease for which molecular‐genetic diagnosis can be pivotal for potentially curative hematopoietic stem cell transplantation. Our work illustrates that cryptic splice variants may elude DNA‐only sequencing and supports broad first‐line use of transcriptome sequencing for children with undiagnosed diseases.
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Affiliation(s)
- Odelia Chorin
- Center for Human Genetics and Genomics, New York University Grossman School of Medicine, New York, NY, USA
| | - Naomi Yachelevich
- Division of Clinical Genetic Services, Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, USA
| | - Khaled Mohamed
- Nordic Bioscience Biomarkers and Research, Herlev, Denmark
| | - Ilana Moscatelli
- Division of Molecular Medicine and Gene Therapy, Lund University, Lund, Sweden
| | - John Pappas
- Division of Clinical Genetic Services, Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, USA
| | - Kim Henriksen
- Nordic Bioscience Biomarkers and Research, Herlev, Denmark
| | - Gilad D Evrony
- Center for Human Genetics and Genomics, New York University Grossman School of Medicine, New York, NY, USA.,Department of Pediatrics, and Department of Neuroscience & Physiology, New York University Grossman School of Medicine, New York, NY, USA
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22
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Bronstein R, Capowski EE, Mehrotra S, Jansen AD, Navarro-Gomez D, Maher M, Place E, Sangermano R, Bujakowska KM, Gamm DM, Pierce EA. A combined RNA-seq and whole genome sequencing approach for identification of non-coding pathogenic variants in single families. Hum Mol Genet 2020; 29:967-979. [PMID: 32011687 PMCID: PMC7158377 DOI: 10.1093/hmg/ddaa016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 11/23/2019] [Accepted: 01/21/2020] [Indexed: 12/13/2022] Open
Abstract
Inherited retinal degenerations (IRDs) are at the focus of current genetic therapeutic advancements. For a genetic treatment such as gene therapy to be successful, an accurate genetic diagnostic is required. Genetic diagnostics relies on the assessment of the probability that a given DNA variant is pathogenic. Non-coding variants present a unique challenge for such assessments as compared to coding variants. For one, non-coding variants are present at much higher number in the genome than coding variants. In addition, our understanding of the rules that govern the non-coding regions of the genome is less complete than our understanding of the coding regions. Methods that allow for both the identification of candidate non-coding pathogenic variants and their functional validation may help overcome these caveats allowing for a greater number of patients to benefit from advancements in genetic therapeutics. We present here an unbiased approach combining whole genome sequencing (WGS) with patient-induced pluripotent stem cell (iPSC)-derived retinal organoids (ROs) transcriptome analysis. With this approach, we identified and functionally validated a novel pathogenic non-coding variant in a small family with a previously unresolved genetic diagnosis.
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Affiliation(s)
- Revital Bronstein
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Ocular Genomics Institute, Boston, MA 02114, USA
| | - Elizabeth E Capowski
- Waisman Center Stem Cell Research Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Sudeep Mehrotra
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Ocular Genomics Institute, Boston, MA 02114, USA
| | - Alex D Jansen
- Waisman Center Stem Cell Research Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Daniel Navarro-Gomez
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Ocular Genomics Institute, Boston, MA 02114, USA
| | - Mathew Maher
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Ocular Genomics Institute, Boston, MA 02114, USA
| | - Emily Place
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Ocular Genomics Institute, Boston, MA 02114, USA
| | - Riccardo Sangermano
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Ocular Genomics Institute, Boston, MA 02114, USA
| | - Kinga M Bujakowska
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Ocular Genomics Institute, Boston, MA 02114, USA
| | - David M Gamm
- Department of Ophthalmology and Visual Sciences, Waisman Center Stem Cell Research Program, McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Eric A Pierce
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Ocular Genomics Institute, Boston, MA 02114, USA
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23
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Yamada Y, Nohata N, Uchida A, Kato M, Arai T, Moriya S, Mizuno K, Kojima S, Yamazaki K, Naya Y, Ichikawa T, Seki N. Replisome genes regulation by antitumor miR-101-5p in clear cell renal cell carcinoma. Cancer Sci 2020; 111:1392-1406. [PMID: 31975570 PMCID: PMC7156888 DOI: 10.1111/cas.14327] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 01/07/2020] [Accepted: 01/12/2020] [Indexed: 12/25/2022] Open
Abstract
Analysis of microRNA (miRNA) regulatory networks is useful for exploring novel biomarkers and therapeutic targets in cancer cells. The Cancer Genome Atlas dataset shows that low expression of both strands of pre‐miR‐101 (miR‐101‐5p and miR‐101‐3p) significantly predicted poor prognosis in clear cell renal cell carcinoma (ccRCC). The functional significance of miR‐101‐5p in cancer cells is poorly understood. Here, we focused on miR‐101‐5p to investigate the antitumor function and its regulatory networks in ccRCC cells. Ectopic expression of mature miRNAs or siRNAs was investigated in cancer cell lines to characterize cell function, ie, proliferation, apoptosis, migration, and invasion. Genome‐wide gene expression and in silico database analyses were undertaken to predict miRNA regulatory networks. Expression of miR‐101‐5p caused cell cycle arrest and apoptosis in ccRCC cells. Downstream neighbor of son (DONSON) was directly regulated by miR‐101‐5p, and its aberrant expression was significantly associated with shorter survival in propensity score‐matched analysis (P = .0001). Knockdown of DONSON attenuated ccRCC cell aggressiveness. Several replisome genes controlled by DONSON and their expression were closely associated with ccRCC pathogenesis. The antitumor miR‐101‐5p/DONSON axis and its modulated replisome genes might be a novel diagnostic and therapeutic target for ccRCC.
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Affiliation(s)
- Yasutaka Yamada
- Department of Functional Genomics, Chiba University Graduate School of Medicine, Chiba, Japan.,Department of Urology, Chiba University Graduate School of Medicine, Chiba, Japan
| | | | - Akifumi Uchida
- Department of Pulmonary Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Mayuko Kato
- Department of Functional Genomics, Chiba University Graduate School of Medicine, Chiba, Japan.,Department of Urology, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Takayuki Arai
- Department of Functional Genomics, Chiba University Graduate School of Medicine, Chiba, Japan.,Department of Urology, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Shogo Moriya
- Department of Biochemistry and Genetics, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Keiko Mizuno
- Department of Pulmonary Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Satoko Kojima
- Department of Urology, Teikyo University Chiba Medical Center, Ichihara, Japan
| | - Kazuto Yamazaki
- Department of Pathology, Teikyo University Chiba Medical Center, Ichihara, Japan
| | - Yukio Naya
- Department of Urology, Teikyo University Chiba Medical Center, Ichihara, Japan
| | - Tomohiko Ichikawa
- Department of Urology, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Naohiko Seki
- Department of Functional Genomics, Chiba University Graduate School of Medicine, Chiba, Japan
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24
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McDaniel SL, Hollatz AJ, Branstad AM, Gaskill MM, Fox CA, Harrison MM. Tissue-Specific DNA Replication Defects in Drosophila melanogaster Caused by a Meier-Gorlin Syndrome Mutation in Orc4. Genetics 2020; 214:355-367. [PMID: 31818869 PMCID: PMC7017028 DOI: 10.1534/genetics.119.302938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 12/05/2019] [Indexed: 02/07/2023] Open
Abstract
Meier-Gorlin syndrome is a rare recessive disorder characterized by a number of distinct tissue-specific developmental defects. Genes encoding members of the origin recognition complex (ORC) and additional proteins essential for DNA replication (CDC6, CDT1, GMNN, CDC45, MCM5, and DONSON) are mutated in individuals diagnosed with MGS. The essential role of ORC is to license origins during the G1 phase of the cell cycle, but ORC has also been implicated in several nonreplicative functions. Because of its essential role in DNA replication, ORC is required for every cell division during development. Thus, it is unclear how the Meier-Gorlin syndrome mutations in genes encoding ORC lead to the tissue-specific defects associated with the disease. To begin to address these issues, we used Cas9-mediated genome engineering to generate a Drosophila melanogaster model of individuals carrying a specific Meier-Gorlin syndrome mutation in ORC4 along with control strains. Together these strains provide the first metazoan model for an MGS mutation in which the mutation was engineered at the endogenous locus along with precisely defined control strains. Flies homozygous for the engineered MGS allele reach adulthood, but with several tissue-specific defects. Genetic analysis revealed that this Orc4 allele was a hypomorph. Mutant females were sterile, and phenotypic analyses suggested that defects in DNA replication was an underlying cause. By leveraging the well-studied Drosophila system, we provide evidence that a disease-causing mutation in Orc4 disrupts DNA replication, and we propose that in individuals with MGS defects arise preferentially in tissues with a high-replication demand.
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Affiliation(s)
- Stephen L McDaniel
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Allison J Hollatz
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Anna M Branstad
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Marissa M Gaskill
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Catherine A Fox
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
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25
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Knapp KM, Sullivan R, Murray J, Gimenez G, Arn P, D'Souza P, Gezdirici A, Wilson WG, Jackson AP, Ferreira C, Bicknell LS. Linked-read genome sequencing identifies biallelic pathogenic variants in DONSON as a novel cause of Meier-Gorlin syndrome. J Med Genet 2019; 57:195-202. [PMID: 31784481 PMCID: PMC7042968 DOI: 10.1136/jmedgenet-2019-106396] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/16/2019] [Accepted: 09/20/2019] [Indexed: 11/20/2022]
Abstract
Material Linked-read whole genome sequencing (WGS) presents a new opportunity for cost-efficient singleton sequencing in place of traditional trio-based designs while generating informative-phased variants, effective for recessive disorders when parental DNA is unavailable. Methods We have applied linked-read WGS to identify novel causes of Meier-Gorlin syndrome (MGORS), a condition recognised by short stature, microtia and patella hypo/aplasia. There are eight genes associated with MGORS to date, all encoding essential components involved in establishing and initiating DNA replication. Results Our successful phasing of linked-read data led to the identification of biallelic rare variants in four individuals (24% of our cohort) in DONSON, a recently established DNA replication fork surveillance factor. The variants include five novel missense and one deep intronic variant. All were demonstrated to be deleterious to function; the missense variants all disrupted the nuclear localisation of DONSON, while the intronic variant created a novel splice site that generated an out-of-frame transcript with no residual canonical transcript produced. Conclusion Variants in DONSON have previously been associated with extreme microcephaly, short stature and limb anomalies and perinatal lethal microcephaly-micromelia syndrome. Our novel genetic findings extend the complicated spectrum of phenotypes associated with DONSON variants and promote novel hypotheses for the role of DONSON in DNA replication. While our findings reiterate that MGORS is a disorder of DNA replication, the pathophysiology is obviously complex. This successful identification of a novel disease gene for MGORS highlights the utility of linked-read WGS as a successful technology to be considered in the genetic studies of recessive conditions.
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Affiliation(s)
- Karen M Knapp
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Rosie Sullivan
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Jennie Murray
- MRC HGU, Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, Edinburgh, UK
| | - Gregory Gimenez
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Pamela Arn
- Nemours Children's Clinic, Jacksonville, Florida, USA
| | - Precilla D'Souza
- Office of the Clinical Director, National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Alper Gezdirici
- Department of Medical Genetics, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey
| | - William G Wilson
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Andrew P Jackson
- MRC HGU, Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, Edinburgh, UK
| | - Carlos Ferreira
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Louise S Bicknell
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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26
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Karaca E, Posey JE, Bostwick B, Liu P, Gezdirici A, Yesil G, Coban Akdemir Z, Bayram Y, Harms FL, Meinecke P, Alawi M, Bacino CA, Sutton VR, Kortüm F, Lupski JR. Biallelic and De Novo Variants in DONSON Reveal a Clinical Spectrum of Cell Cycle-opathies with Microcephaly, Dwarfism and Skeletal Abnormalities. Am J Med Genet A 2019; 179:2056-2066. [PMID: 31407851 DOI: 10.1002/ajmg.a.61315] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 07/10/2019] [Accepted: 07/14/2019] [Indexed: 01/30/2023]
Abstract
Co-occurrence of primordial dwarfism and microcephaly together with particular skeletal findings are seen in a wide range of Mendelian syndromes including microcephaly micromelia syndrome (MMS, OMIM 251230), microcephaly, short stature, and limb abnormalities (MISSLA, OMIM 617604), and microcephalic primordial dwarfisms (MPDs). Genes associated with these syndromes encode proteins that have crucial roles in DNA replication or in other critical steps of the cell cycle that link DNA replication to cell division. We identified four unrelated families with five affected individuals having biallelic or de novo variants in DONSON presenting with a core phenotype of severe short stature (z score < -3 SD), additional skeletal abnormalities, and microcephaly. Two apparently unrelated families with identical homozygous c.631C > T p.(Arg211Cys) variant had clinical features typical of Meier-Gorlin syndrome (MGS), while two siblings with compound heterozygous c.346delG p.(Asp116Ile*62) and c.1349A > G p.(Lys450Arg) variants presented with Seckel-like phenotype. We also identified a de novo c.683G > T p.(Trp228Leu) variant in DONSON in a patient with prominent micrognathia, short stature and hypoplastic femur and tibia, clinically diagnosed with Femoral-Facial syndrome (FFS, OMIM 134780). Biallelic variants in DONSON have been recently described in individuals with microcephalic dwarfism. These studies also demonstrated that DONSON has an essential conserved role in the cell cycle. Here we describe novel biallelic and de novo variants that are associated with MGS, Seckel-like phenotype and FFS, the last of which has not been associated with any disease gene to date.
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Affiliation(s)
- Ender Karaca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Bret Bostwick
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Texas Children's Hospital, Baylor College of Medicine, Houston, Texas
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Alper Gezdirici
- Department of Medical Genetics, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey
| | - Gozde Yesil
- Department of Medical Genetics, Bezmialem University, Istanbul, Turkey
| | - Zeynep Coban Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Yavuz Bayram
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Frederike L Harms
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Peter Meinecke
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Malik Alawi
- Bioinformatics Service Facility, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Center for Bioinformatics, University of Hamburg, Hamburg, Germany.,Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Virus Genomics, Hamburg, Germany
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Texas Children's Hospital, Baylor College of Medicine, Houston, Texas
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Texas Children's Hospital, Baylor College of Medicine, Houston, Texas
| | - Fanny Kortüm
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Texas Children's Hospital, Baylor College of Medicine, Houston, Texas.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas.,Department of Pediatrics, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas
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27
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Large-scale neuroanatomical study uncovers 198 gene associations in mouse brain morphogenesis. Nat Commun 2019; 10:3465. [PMID: 31371714 PMCID: PMC6671969 DOI: 10.1038/s41467-019-11431-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/13/2019] [Indexed: 01/03/2023] Open
Abstract
Brain morphogenesis is an important process contributing to higher-order cognition, however our knowledge about its biological basis is largely incomplete. Here we analyze 118 neuroanatomical parameters in 1,566 mutant mouse lines and identify 198 genes whose disruptions yield NeuroAnatomical Phenotypes (NAPs), mostly affecting structures implicated in brain connectivity. Groups of functionally similar NAP genes participate in pathways involving the cytoskeleton, the cell cycle and the synapse, display distinct fetal and postnatal brain expression dynamics and importantly, their disruption can yield convergent phenotypic patterns. 17% of human unique orthologues of mouse NAP genes are known loci for cognitive dysfunction. The remaining 83% constitute a vast pool of genes newly implicated in brain architecture, providing the largest study of mouse NAP genes and pathways. This offers a complementary resource to human genetic studies and predict that many more genes could be involved in mammalian brain morphogenesis. Brain morphogenesis is an important process contributing to higher-order cognition, however our knowledge about its biological basis is largely incomplete. Here, authors analyzed 118 neuroanatomical parameters in 1,566 mutant mouse lines to identify 198 genes whose disruptions yield neuroanatomical phenotypes
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28
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Differentiation of MISSLA and Fanconi anaemia by computer-aided image analysis and presentation of two novel MISSLA siblings. Eur J Hum Genet 2019; 27:1827-1835. [PMID: 31320746 DOI: 10.1038/s41431-019-0469-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 06/07/2019] [Accepted: 06/25/2019] [Indexed: 01/15/2023] Open
Abstract
Variants in DONSON were recently identified as the cause of microcephaly, short stature, and limb abnormalities syndrome (MISSLA). The clinical spectra of MISSLA and Fanconi anaemia (FA) strongly overlap. For that reason, some MISSLA patients have been clinically diagnosed with FA. Here, we present the clinical data of siblings with MISSLA featuring a novel DONSON variant and summarize the current literature on MISSLA. Additionally, we perform computer-aided image analysis using the DeepGestalt technology to test how distinct the facial features of MISSLA and FA patients are. We show that MISSLA has a specific facial gestalt. Notably, we find that also FA patients feature facial characteristics recognizable by computer-aided image analysis. We conclude that computer-assisted image analysis improves diagnostic precision in both MISSLA and FA.
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29
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Kermi C, Aze A, Maiorano D. Preserving Genome Integrity During the Early Embryonic DNA Replication Cycles. Genes (Basel) 2019; 10:genes10050398. [PMID: 31137726 PMCID: PMC6563053 DOI: 10.3390/genes10050398] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/15/2019] [Indexed: 02/06/2023] Open
Abstract
During the very early stages of embryonic development chromosome replication occurs under rather challenging conditions, including a very short cell cycle, absence of transcription, a relaxed DNA damage response and, in certain animal species, a highly contracted S-phase. This raises the puzzling question of how the genome can be faithfully replicated in such a peculiar metabolic context. Recent studies have provided new insights into this issue, and unveiled that embryos are prone to accumulate genetic and genomic alterations, most likely due to restricted cellular functions, in particular reduced DNA synthesis quality control. These findings may explain the low rate of successful development in mammals and the occurrence of diseases, such as abnormal developmental features and cancer. In this review, we will discuss recent findings in this field and put forward perspectives to further study this fascinating question.
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Affiliation(s)
- Chames Kermi
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5441, USA.
| | - Antoine Aze
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
| | - Domenico Maiorano
- Laboratoire Surveillance et Stabilité du Génome, Institut de Génétique Humaine, UMR9002, CNRS, Université de Montpellier, 34090 Montpellier, France.
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30
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Abdelrahman HA, John A, Ali BR, Al-Gazali L. Further Delineation of the Microcephaly-Micromelia Syndrome Associated with Loss-of-Function Variants in DONSON. Mol Syndromol 2019; 10:171-176. [PMID: 31191207 DOI: 10.1159/000497337] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2019] [Indexed: 02/05/2023] Open
Abstract
The DONSON gene encodes the downstream neighbor of SON, a replisome component that stabilizes the replication fork during replication. A severe form of microcephalic dwarfism, microcephaly-micromelia syndrome (MIMIS), has been recently associated with DONSON biallelic loss of function. Affected fetuses suffer severe growth restriction, microcephaly, and variable limb malformations which result in intrauterine or perinatal death. All described fetuses carried a homozygous founder mutation (c.1047-9A>G), a splice-altering variant that leads to transcript degradation. We evaluated 2 newborns from a consanguineous Emirati family with severe microcephaly, micromelia, craniofacial dysmorphism, and skeletal abnormalities; both died shortly after birth. Here, we report the second homozygous loss-of-function variant (c.763C>T) in DONSON causing MIMIS, and we provide detailed clinical description of this very rare disorder. In addition, we review all MIMIS cases in the literature and summarize the striking features of this phenotype. This manuscript is aimed to increase the clinical understanding of this rare, extremely severe disorder and encourage clinical and molecular geneticists to consider screening for DONSON loss-of-function variants in families with recurrent pregnancy loss and/or perinatal deaths.
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Affiliation(s)
| | - Anne John
- Department of Pathology, United Arab Emirates University, Al Ain, UAE
| | - Bassam R Ali
- Department of Pathology, United Arab Emirates University, Al Ain, UAE.,Department of Zayed Center for Health Sciences, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, UAE
| | - Lihadh Al-Gazali
- Department of Pediatrics, United Arab Emirates University, Al Ain, UAE
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31
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Howe DG, Blake JA, Bradford YM, Bult CJ, Calvi BR, Engel SR, Kadin JA, Kaufman TC, Kishore R, Laulederkind SJF, Lewis SE, Moxon SAT, Richardson JE, Smith C. Model organism data evolving in support of translational medicine. Lab Anim (NY) 2018; 47:277-289. [PMID: 30224793 PMCID: PMC6322546 DOI: 10.1038/s41684-018-0150-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 08/13/2018] [Indexed: 02/07/2023]
Abstract
Model organism databases (MODs) have been collecting and integrating biomedical research data for 30 years and were designed to meet specific needs of each model organism research community. The contributions of model organism research to understanding biological systems would be hard to overstate. Modern molecular biology methods and cost reductions in nucleotide sequencing have opened avenues for direct application of model organism research to elucidating mechanisms of human diseases. Thus, the mandate for model organism research and databases has now grown to include facilitating use of these data in translational applications. Challenges in meeting this opportunity include the distribution of research data across many databases and websites, a lack of data format standards for some data types, and sustainability of scale and cost for genomic database resources like MODs. The issues of widely distributed data and application of data standards are some of the challenges addressed by FAIR (Findable, Accessible, Interoperable, and Re-usable) data principles. The Alliance of Genome Resources is now moving to address these challenges by bringing together expertly curated research data from fly, mouse, rat, worm, yeast, zebrafish, and the Gene Ontology consortium. Centralized multi-species data access, integration, and format standardization will lower the data utilization barrier in comparative genomics and translational applications and will provide a framework in which sustainable scale and cost can be addressed. This article presents a brief historical perspective on how the Alliance model organisms are complementary and how they have already contributed to understanding the etiology of human diseases. In addition, we discuss four challenges for using data from MODs in translational applications and how the Alliance is working to address them, in part by applying FAIR data principles. Ultimately, combined data from these animal models are more powerful than the sum of the parts.
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Affiliation(s)
- Douglas G Howe
- The Institute of Neuroscience, University of Oregon, Eugene, OR, USA.
| | | | - Yvonne M Bradford
- The Institute of Neuroscience, University of Oregon, Eugene, OR, USA
| | | | - Brian R Calvi
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Stacia R Engel
- Department of Genetics, Stanford University, Palo Alto, CA, USA
| | | | | | - Ranjana Kishore
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Stanley J F Laulederkind
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI, USA
| | - Suzanna E Lewis
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Sierra A T Moxon
- The Institute of Neuroscience, University of Oregon, Eugene, OR, USA
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32
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Abstract
Primary microcephaly (MCPH, for "microcephaly primary hereditary") is a disorder of brain development that results in a head circumference more than 3 standard deviations below the mean for age and gender. It has a wide variety of causes, including toxic exposures, in utero infections, and metabolic conditions. While the genetic microcephaly syndromes are relatively rare, studying these syndromes can reveal molecular mechanisms that are critical in the regulation of neural progenitor cells, brain size, and human brain evolution. Many of the causative genes for MCPH encode centrosomal proteins involved in centriole biogenesis. However, other MCPH genes fall under different mechanistic categories, notably DNA replication and repair. Recent gene discoveries and functional studies have implicated novel cellular processes, such as cytokinesis, centromere and kinetochore function, transmembrane or intracellular transport, Wnt signaling, and autophagy, as well as the apical polarity complex. Thus, MCPH genes implicate a wide variety of molecular and cellular mechanisms in the regulation of cerebral cortical size during development.
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Affiliation(s)
- Divya Jayaraman
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Harvard-MIT MD-PhD Program, Harvard Medical School, Boston, Massachusetts 02115, USA.,Current affiliation: Boston Combined Residency Program (Child Neurology), Boston Children's Hospital, Boston, Massachusetts 02115, USA;
| | - Byoung-Il Bae
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06510, USA;
| | - Christopher A Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Departments of Pediatrics and Neurology, Harvard Medical School, Boston, Massachusetts 02115, USA;
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33
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Schulz S, Mensah MA, de Vries H, Fröber R, Romeike B, Schneider U, Borte S, Schindler D, Kentouche K. Microcephaly, short stature, and limb abnormality disorder due to novel autosomal biallelic DONSON mutations in two German siblings. Eur J Hum Genet 2018; 26:1282-1287. [PMID: 29760432 DOI: 10.1038/s41431-018-0128-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/31/2018] [Accepted: 02/13/2018] [Indexed: 12/11/2022] Open
Abstract
Recently, variants in DONSON have been reported to cause different disorders of the microcephalic primordial dwarfism spectrum. Using whole-exome sequencing, we identified two novel, compound heterozygous DONSON variants in a pair of siblings, one of whom was previously diagnosed with Fanconi anemia. This occurred because the present cases exhibited clinical findings in addition to those of the microcephalic primordial dwarfism disorder, including severe limb malformations. These findings suggest that the DONSON and Fanconi anemia proteins could have supplementary roles in developmental processes as they have in the maintenance of genomic integrity, resulting in related disease phenotypes.
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Affiliation(s)
- Solveig Schulz
- Center of Human Genetics, Jena University Hospital, Jena, Germany.
| | - Martin A Mensah
- Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Institute of Medical Genetics and Human Genetics, Berlin, Germany.,Berlin Institute of Health (BIH), 10178, Berlin, Germany
| | - Heike de Vries
- Department of Pediatrics, Jena University Hospital, Jena, Germany
| | | | - Bernd Romeike
- Department of Neuropathology, Jena University Hospital, Jena, Germany
| | - Uwe Schneider
- Clinic of Obstetrics and Gynecology, Jena University Hospital, Jena, Germany
| | - Stephan Borte
- Jeffrey Modell Diagnostic and Research Center for Primary Immunodeficiencies at the Municipal Hospital St. Georg, Leipzig, Germany
| | - Detlev Schindler
- Department of Human Genetics, Institute of Human Genetics, Biozentrum, University of Wurzburg, Wurzburg, Germany
| | - Karim Kentouche
- Department of Pediatrics, Jena University Hospital, Jena, Germany
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34
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Rapid DNA Synthesis During Early Drosophila Embryogenesis Is Sensitive to Maternal Humpty Dumpty Protein Function. Genetics 2017; 207:935-947. [PMID: 28942426 DOI: 10.1534/genetics.117.300318] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/20/2017] [Indexed: 12/29/2022] Open
Abstract
Problems with DNA replication cause cancer and developmental malformations. It is not fully understood how DNA replication is coordinated with development and perturbed in disease. We had previously identified the Drosophila gene humpty dumpty (hd), and showed that null alleles cause incomplete DNA replication, tissue undergrowth, and lethality. Animals homozygous for the missense allele, hd272-9 , were viable, but adult females had impaired amplification of eggshell protein genes in the ovary, resulting in the maternal effects of thin eggshells and embryonic lethality. Here, we show that expression of an hd transgene in somatic cells of the ovary rescues amplification and eggshell synthesis but not embryo viability. The germline of these mothers remain mutant for the hd272-9 allele, resulting in reduced maternal Hd protein and embryonic arrest during mitosis of the first few S/M nuclear cleavage cycles with chromosome instability and chromosome bridges. Epistasis analysis of hd with the rereplication mutation plutonium indicates that the chromosome bridges of hd embryos are the result of a failed attempt to segregate incompletely replicated sister chromatids. This study reveals that maternally encoded Humpty dumpty protein is essential for DNA replication and genome integrity during the little-understood embryonic S/M cycles. Moreover, the two hd272-9 maternal-effect phenotypes suggest that ovarian gene amplification and embryonic cleavage are two time periods in development that are particularly sensitive to mild deficits in DNA replication function. This last observation has broader relevance for interpreting why mild mutations in the human ortholog of humpty dumpty and other DNA replication genes cause tissue-specific malformations of microcephalic dwarfisms.
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