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Saima, Khan A, Ali S, Jiang J, Miao Z, Kamil A, Khan SN, Arold ST. Clinical genomics expands the link between erroneous cell division, primary microcephaly and intellectual disability. Neurogenetics 2024:10.1007/s10048-024-00759-7. [PMID: 38795246 DOI: 10.1007/s10048-024-00759-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Accepted: 04/09/2024] [Indexed: 05/27/2024]
Abstract
Primary microcephaly is a rare neurogenic and genetically heterogeneous disorder characterized by significant brain size reduction that results in numerous neurodevelopmental disorders (NDD) problems, including mild to severe intellectual disability (ID), global developmental delay (GDD), seizures and other congenital malformations. This disorder can arise from a mutation in genes involved in various biological pathways, including those within the brain. We characterized a recessive neurological disorder observed in nine young adults from five independent consanguineous Pakistani families. The disorder is characterized by microcephaly, ID, developmental delay (DD), early-onset epilepsy, recurrent infection, hearing loss, growth retardation, skeletal and limb defects. Through exome sequencing, we identified novel homozygous variants in five genes that were previously associated with brain diseases, namely CENPJ (NM_018451.5: c.1856A > G; p.Lys619Arg), STIL (NM_001048166.1: c.1235C > A; p.(Pro412Gln), CDK5RAP2 (NM_018249.6 c.3935 T > G; p.Leu1312Trp), RBBP8 (NM_203291.2 c.1843C > T; p.Gln615*) and CEP135 (NM_025009.5 c.1469A > G; p.Glu490Gly). These variants were validated by Sanger sequencing across all family members, and in silico structural analysis. Protein 3D homology modeling of wild-type and mutated proteins revealed substantial changes in the structure, suggesting a potential impact on function. Importantly, all identified genes play crucial roles in maintaining genomic integrity during cell division, with CENPJ, STIL, CDK5RAP2, and CEP135 being involved in centrosomal function. Collectively, our findings underscore the link between erroneous cell division, particularly centrosomal function, primary microcephaly and ID.
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Affiliation(s)
- Saima
- Department of Biotechnology, Abdul Wali Khan University, Mardan, 23200, Khyber Pakhtunkhwa, Pakistan
| | - Amjad Khan
- Department of Zoology, University of Lakki Marwat, Lakki, 28420, Khyber Pakhtunkhwa, Pakistan.
- Institute for Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.
- Alexander Von Humboldt Fellowship Foundation, Berlin, Germany.
| | - Sajid Ali
- Department of Biotechnology, Abdul Wali Khan University, Mardan, 23200, Khyber Pakhtunkhwa, Pakistan
| | - Jiuhong Jiang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Guangzhou National Laboratory, Guangzhou International Bio Island, Guangzhou, China
| | - Zhichao Miao
- GMU-GIBH Joint School of Life Sciences, The Guangdong-Hong Kong-Macau Joint Laboratory for Cell Fate Regulation and Diseases, Guangzhou National Laboratory, Guangzhou Medical University, Guangzhou, China
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Atif Kamil
- Department of Biotechnology, Abdul Wali Khan University, Mardan, 23200, Khyber Pakhtunkhwa, Pakistan
- Department of Internal Medicine, Brody Medicine School, East Carolina University, Greenville, NC, USA
| | - Shahid Niaz Khan
- Department of Zoology, Kohat University of Science & Technology, Kohat, 26000, Khyber Pakhtunkhwa, Pakistan
| | - Stefan T Arold
- Biological and Environmental Science and Engineering Division, Computational Biology Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
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2
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Dai W, Liu Z, Yan M, Nian X, Hong F, Zhou Z, Wang C, Fu X, Li X, Jiang M, Zhu Y, Huang Q, Lu X, Hou L, Yan N, Wang Q, Hu J, Mo W, Zhang X, Zhang L. Nucleoporin Seh1 controls murine neocortical development via transcriptional repression of p21 in neural stem cells. Dev Cell 2024; 59:482-495.e6. [PMID: 38272027 DOI: 10.1016/j.devcel.2024.01.002] [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: 11/08/2022] [Revised: 06/21/2023] [Accepted: 01/05/2024] [Indexed: 01/27/2024]
Abstract
Mutations or dysregulation of nucleoporins (Nups) are strongly associated with neural developmental diseases, yet the underlying mechanisms remain poorly understood. Here, we show that depletion of Nup Seh1 in radial glial progenitors results in defective neural progenitor proliferation and differentiation that ultimately manifests in impaired neurogenesis and microcephaly. This loss of stem cell proliferation is not associated with defects in the nucleocytoplasmic transport. Rather, transcriptome analysis showed that ablation of Seh1 in neural stem cells derepresses the expression of p21, and knockdown of p21 partially restored self-renewal capacity. Mechanistically, Seh1 cooperates with the NuRD transcription repressor complex at the nuclear periphery to regulate p21 expression. Together, these findings identified that Nups regulate brain development by exerting a chromatin-associated role and affecting neural stem cell proliferation.
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Affiliation(s)
- Wenxiu Dai
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Zhixiong Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China; Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai 519031, China
| | - Minbiao Yan
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Ximing Nian
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Fan Hong
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Zhihao Zhou
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Chaomeng Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Xing Fu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Xuewen Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Mengyun Jiang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Yanqin Zhu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Qiuying Huang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Xiaoyun Lu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Lichao Hou
- Department of Anesthesiology, Xiang'an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361102, Fujian, China
| | - Ning Yan
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Qin Wang
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Jin Hu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Wei Mo
- Sir Run Run Shaw Hospital, Department of Immunology, School of Basic Medical Science, Zhejiang University School of Medicine, Hangzhou 310058, China; Liangzhu Laboratory, Hangzhou 311121, China
| | - Xueqin Zhang
- Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Xiamen University, Xiamen 361102, Fujian, China
| | - Liang Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Neuroscience, the First Affiliated Hospital, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China; Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Xiamen University, Xiamen 361102, Fujian, China.
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3
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Kaygusuz E, Khayyat AIA, Abdullah U, Budde BS, Asif M, Ahmed I, Makhdoom EUH, Sur-Erdem I, Baig JM, Khan MMA, Toliat MR, Becker C, Anwar H, Iqbal M, Fischer S, Jameel M, Sher M, Tariq M, Malik NA, Noegel AA, Hassan MJ, Thiele H, Tinschert S, Eichinger L, Höning S, Baig SM, Nürnberg P, Hussain MS. A 24-generation-old founder mutation impairs splicing of RBBP8 in Pakistani families affected with Jawad syndrome. Clin Genet 2021; 100:486-488. [PMID: 34270086 DOI: 10.1111/cge.14028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/05/2021] [Accepted: 07/07/2021] [Indexed: 11/27/2022]
Abstract
Jawad syndrome is a multiple congenital anomaly and intellectual disability syndrome with mutation in RBBP8 reported only in two families. Here, we report on two new families from Pakistan and identified a previously reported variant in RBBP8, NM_002894.3:c.1808-1809delTA. We could show that this mutation impairs splicing resulting in two different abnormal transcripts. Finally, we could verify a shared haplotype among all four families and estimate the founder event to have occurred some 24 generations ago.
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Affiliation(s)
- Emrah Kaygusuz
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.,Molecular Biology and Genetics, Bilecik Şeyh Edebali University, Bilecik, Turkey
| | - Arwa Ishaq A Khayyat
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.,Biochemistry Department, King Saud University, Riyadh, Saudi Arabia
| | - Uzma Abdullah
- University Institute of Biochemistry and Biotechnology, PMAS-Arid Agriculture University, Rawalpindi, Pakistan
| | - Birgit Susanne Budde
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Maria Asif
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Ilyas Ahmed
- Institute for Cardiogenetics, University of Luebeck, Luebeck, Germany
| | - Ehtisham Ul Haq Makhdoom
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.,Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE) College, PIEAS, Faisalabad, Pakistan.,Department of Physiology, Government College University, Faisalabad, Pakistan
| | - Ilknur Sur-Erdem
- Department of Molecular Biology, Koc University School of Medicine, Istanbul, Turkey
| | - Jamshaid Mahmood Baig
- Department of Bioinformatics and Biotechnology, International Islamic University, Islamabad, Pakistan
| | - Muhammad Mohsin Ali Khan
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE) College, PIEAS, Faisalabad, Pakistan
| | - Mohammad Reza Toliat
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Christian Becker
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Haseeb Anwar
- Department of Physiology, Government College University, Faisalabad, Pakistan
| | - Maria Iqbal
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.,Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE) College, PIEAS, Faisalabad, Pakistan
| | - Sarah Fischer
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Muhammad Jameel
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE) College, PIEAS, Faisalabad, Pakistan
| | - Muhammad Sher
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE) College, PIEAS, Faisalabad, Pakistan
| | - Muhammad Tariq
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE) College, PIEAS, Faisalabad, Pakistan
| | - Naveed Altaf Malik
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE) College, PIEAS, Faisalabad, Pakistan
| | - Angelika A Noegel
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Muhammad Jawad Hassan
- Department of Biological Sciences, National University of Medical Sciences, Rawalpindi, Pakistan
| | - Holger Thiele
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Sigrid Tinschert
- Zentrum Medizinische Genetik, Medizinische Universität, Innsbruck, Austria
| | - Ludwig Eichinger
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Stefan Höning
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Shahid Mahmood Baig
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE) College, PIEAS, Faisalabad, Pakistan
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Muhammad Sajid Hussain
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
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4
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Cody JD. The Consequences of Abnormal Gene Dosage: Lessons from Chromosome 18. Trends Genet 2020; 36:764-776. [PMID: 32660784 DOI: 10.1016/j.tig.2020.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/18/2022]
Abstract
Accurate interpretation of genomic copy number variation (CNV) remains a challenge and has important consequences for both congenital and late-onset disease. Hemizygosity dosage characterization of the genes on chromosome 18 reveals a spectrum of outcomes ranging from no clinical effect, to risk factors for disease, to both low- and high-penetrance disease. These data are important for accurate and predictive clinical management. Additionally, the potential mechanisms of reduced penetrance due to dosage compensation are discussed as a key to understanding avenues for potential treatment. This review describes the chromosome 18 findings, and discusses the molecular mechanisms that allow haploinsufficiency, reduced penetrance, and dosage compensation.
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Affiliation(s)
- Jannine DeMars Cody
- Department of Pediatrics, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Chromosome 18 Registry and Research Society, San Antonio, TX 78229, USA.
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5
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Al-Naama N, Mackeh R, Kino T. C 2H 2-Type Zinc Finger Proteins in Brain Development, Neurodevelopmental, and Other Neuropsychiatric Disorders: Systematic Literature-Based Analysis. Front Neurol 2020; 11:32. [PMID: 32117005 PMCID: PMC7034409 DOI: 10.3389/fneur.2020.00032] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/10/2020] [Indexed: 12/15/2022] Open
Abstract
Neurodevelopmental disorders (NDDs) are multifaceted pathologic conditions manifested with intellectual disability, autistic features, psychiatric problems, motor dysfunction, and/or genetic/chromosomal abnormalities. They are associated with skewed neurogenesis and brain development, in part through dysfunction of the neural stem cells (NSCs) where abnormal transcriptional regulation on key genes play significant roles. Recent accumulated evidence highlights C2H2-type zinc finger proteins (C2H2-ZNFs), the largest transcription factor family in humans, as important targets for the pathologic processes associated with NDDs. In this review, we identified their significant accumulation (74 C2H2-ZNFs: ~10% of all human member proteins) in brain physiology and pathology. Specifically, we discuss their physiologic contribution to brain development, particularly focusing on their actions in NSCs. We then explain their pathologic implications in various forms of NDDs, such as morphological brain abnormalities, intellectual disabilities, and psychiatric disorders. We found an important tendency that poly-ZNFs and KRAB-ZNFs tend to be involved in the diseases that compromise gross brain structure and human-specific higher-order functions, respectively. This may be consistent with their characteristic appearance in the course of species evolution and corresponding contribution to these brain activities.
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Affiliation(s)
- Njoud Al-Naama
- Laboratory of Molecular and Genomic Endocrinology, Division of Translational Medicine, Sidra Medicine, Doha, Qatar
| | - Rafah Mackeh
- Laboratory of Molecular and Genomic Endocrinology, Division of Translational Medicine, Sidra Medicine, Doha, Qatar
| | - Tomoshige Kino
- Laboratory of Molecular and Genomic Endocrinology, Division of Translational Medicine, Sidra Medicine, Doha, Qatar
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6
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Petr MA, Tulika T, Carmona-Marin LM, Scheibye-Knudsen M. Protecting the Aging Genome. Trends Cell Biol 2020; 30:117-132. [DOI: 10.1016/j.tcb.2019.12.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/27/2019] [Accepted: 12/02/2019] [Indexed: 12/15/2022]
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7
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Bioinformatics analysis of regulatory elements of the CD151 gene and insilico docking of CD151 with diallyl sulfide. GENE REPORTS 2019. [DOI: 10.1016/j.genrep.2019.100551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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8
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Liu Z, Yan M, Liang Y, Liu M, Zhang K, Shao D, Jiang R, Li L, Wang C, Nussenzveig DR, Zhang K, Chen S, Zhong C, Mo W, Fontoura BMA, Zhang L. Nucleoporin Seh1 Interacts with Olig2/Brd7 to Promote Oligodendrocyte Differentiation and Myelination. Neuron 2019; 102:587-601.e7. [PMID: 30876848 DOI: 10.1016/j.neuron.2019.02.018] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/12/2019] [Accepted: 02/13/2019] [Indexed: 01/10/2023]
Abstract
Nucleoporins (Nups) are involved in neural development, and alterations in Nup genes are linked to human neurological diseases. However, physiological functions of specific Nups and the underlying mechanisms involved in these processes remain elusive. Here, we show that tissue-specific depletion of the nucleoporin Seh1 causes dramatic myelination defects in the CNS. Although proliferation is not altered in Seh1-deficient oligodendrocyte progenitor cells (OPCs), they fail to differentiate into mature oligodendrocytes, which impairs myelin production and remyelination after demyelinating injury. Genome-wide analyses show that Seh1 regulates a core myelinogenic regulatory network and establishes an accessible chromatin landscape. Mechanistically, Seh1 regulates OPCs differentiation by assembling Olig2 and Brd7 into a transcription complex at nuclear periphery. Together, our results reveal that Seh1 is required for oligodendrocyte differentiation and myelination by promoting assembly of an Olig2-dependent transcription complex and define a nucleoporin as a key player in the CNS.
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Affiliation(s)
- Zhixiong Liu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China; Cancer Research Center of Xiamen University, Xiamen, Fujian 361102, China
| | - Minbiao Yan
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China; Cancer Research Center of Xiamen University, Xiamen, Fujian 361102, China
| | - Yaoji Liang
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian 361102, China; XMU School of Pharmaceutical Sciences-Amogene Joint R&D Center for Genetic Diagnostics, Amogene Biotech, Xiamen, Fujian 361102, China; The First Affiliated Hospital, Medical College, Xiamen University, Xiamen, Fujian 361102, China
| | - Min Liu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Kun Zhang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Dandan Shao
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Rencai Jiang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Li Li
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Chaomeng Wang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Daniel R Nussenzveig
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA; Veterans Affairs North Texas Health Care System: Dallas VA Medical Center, Dallas, TX 75216, USA
| | - Kunkun Zhang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Shaoxuan Chen
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Chuanqi Zhong
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Wei Mo
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Beatriz M A Fontoura
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Liang Zhang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China; Cancer Research Center of Xiamen University, Xiamen, Fujian 361102, China.
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9
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Abstract
Vertebrate CtIP, and its fission yeast (Ctp1), budding yeast (Sae2) and plant (Com1) orthologs have emerged as key regulatory molecules in cellular responses to DNA double strand breaks (DSBs). By modulating the nucleolytic 5'-3' resection activity of the Mre11/Rad50/Nbs1 (MRN) DSB repair processing and signaling complex, CtIP/Ctp1/Sae2/Com1 is integral to the channeling of DNA double strand breaks through DSB repair by homologous recombination (HR). Nearly two decades since its discovery, emerging new data are defining the molecular underpinnings for CtIP DSB repair regulatory activities. CtIP homologs are largely intrinsically unstructured proteins comprised of expanded regions of low complexity sequence, rather than defined folded domains typical of DNA damage metabolizing enzymes and nucleases. A compact structurally conserved N-terminus forms a functionally critical tetrameric helical dimer of dimers (THDD) region that bridges CtIP oligomers, and is flexibly appended to a conserved C-terminal Sae2-homology DNA binding and DSB repair pathway choice regulatory hub which influences nucleolytic activities of the MRN core nuclease complex. The emerging evidence from structural, biophysical, and biological studies converges on CtIP having functional roles in DSB repair that include: 1) dynamic DNA strand coordination through direct DNA binding and DNA bridging activities, 2) MRN nuclease complex cofactor functions that direct MRN endonucleolytic cleavage of protein-blocked DSB ends and 3) acting as a protein binding hub targeted by the cell cycle regulatory apparatus, which influences CtIP expression and activity via layers of post-translational modifications, protein-protein interactions and DNA binding.
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Affiliation(s)
- Sara N Andres
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, United States
| | - R Scott Williams
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, United States.
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10
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Blazejczyk M, Macias M, Korostynski M, Firkowska M, Piechota M, Skalecka A, Tempes A, Koscielny A, Urbanska M, Przewlocki R, Jaworski J. Kainic Acid Induces mTORC1-Dependent Expression of Elmo1 in Hippocampal Neurons. Mol Neurobiol 2017; 54:2562-2578. [PMID: 26993296 PMCID: PMC5390005 DOI: 10.1007/s12035-016-9821-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/29/2016] [Indexed: 12/24/2022]
Abstract
Epileptogenesis is a process triggered by initial environmental or genetic factors that result in epilepsy and may continue during disease progression. Important parts of this process include changes in transcriptome and the pathological rewiring of neuronal circuits that involves changes in neuronal morphology. Mammalian/mechanistic target of rapamycin (mTOR) is upregulated by proconvulsive drugs, e.g., kainic acid, and is needed for progression of epileptogenesis, but molecular aspects of its contribution are not fully understood. Since mTOR can modulate transcription, we tested if rapamycin, an mTOR complex 1 inhibitor, affects kainic acid-evoked transcriptome changes. Using microarray technology, we showed that rapamycin inhibits the kainic acid-induced expression of multiple functionally heterogeneous genes. We further focused on engulfment and cell motility 1 (Elmo1), which is a modulator of actin dynamics and therefore could contribute to pathological rewiring of neuronal circuits during epileptogenesis. We showed that prolonged overexpression of Elmo1 in cultured hippocampal neurons increased axonal growth, decreased dendritic spine density, and affected their shape. In conclusion, data presented herein show that increased mTORC1 activity in response to kainic acid has no global effect on gene expression. Instead, our findings suggest that mTORC1 inhibition may affect development of epilepsy, by modulating expression of specific subset of genes, including Elmo1, and point to a potential role for Elmo1 in morphological changes that accompany epileptogenesis.
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Affiliation(s)
- Magdalena Blazejczyk
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 02-109, Warsaw, Poland.
| | - Matylda Macias
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 02-109, Warsaw, Poland
| | - Michal Korostynski
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna St, 31-343, Krakow, Poland
| | - Marcelina Firkowska
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 02-109, Warsaw, Poland
| | - Marcin Piechota
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna St, 31-343, Krakow, Poland
| | - Agnieszka Skalecka
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 02-109, Warsaw, Poland
| | - Aleksandra Tempes
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 02-109, Warsaw, Poland
| | - Alicja Koscielny
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 02-109, Warsaw, Poland
| | - Malgorzata Urbanska
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 02-109, Warsaw, Poland
| | - Ryszard Przewlocki
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna St, 31-343, Krakow, Poland
| | - Jacek Jaworski
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 02-109, Warsaw, Poland.
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11
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Ganapathiraju MK, Karunakaran KB, Correa-Menéndez J. Predicted protein interactions of IFITMs may shed light on mechanisms of Zika virus-induced microcephaly and host invasion. F1000Res 2016; 5:1919. [PMID: 29333229 PMCID: PMC5747333 DOI: 10.12688/f1000research.9364.2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/04/2017] [Indexed: 12/22/2022] Open
Abstract
After the first reported case of Zika virus (ZIKV) in Brazil, in 2015, a significant increase in the reported cases of microcephaly was observed. Microcephaly is a neurological condition in which the infant’s head is significantly smaller with complications in brain development. Recently, two small membrane-associated interferon-inducible transmembrane proteins (IFITM1 and IFITM3) have been shown to repress members of the flaviviridae family which includes ZIKV. However, the exact mechanisms leading to the inhibition of the virus are yet unknown. Here, we assembled an interactome of IFITM1 and IFITM3 with known protein-protein interactions (PPIs) collected from publicly available databases and novel PPIs predicted using the High-confidence Protein-Protein Interaction Prediction (HiPPIP) model. We analyzed the functional and pathway associations of the interacting proteins, and found that there are several immunity pathways (toll-like receptor signaling, cd28 signaling in T-helper cells, crosstalk between dendritic cells and natural killer cells), neuronal pathways (axonal guidance signaling, neural tube closure and actin cytoskeleton signaling) and developmental pathways (neural tube closure, embryonic skeletal system development) that are associated with these interactors. Our novel PPIs associate cilia dysfunction in ependymal cells to microcephaly, and may also shed light on potential targets of ZIKV for host invasion by immunosuppression and cytoskeletal rearrangements. These results could help direct future research in elucidating the mechanisms underlying host defense to ZIKV and other flaviviruses.
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Affiliation(s)
- Madhavi K Ganapathiraju
- Intelligent Systems Program, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kalyani B Karunakaran
- Supercomputer Education and Research Centre, Indian Institute of Science, Bangalore, India
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12
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Ullah MI, Ahmad A, Raza SI, Amar A, Ali A, Bhatti A, John P, Mohyuddin A, Ahmad W, Hassan MJ. In silico analysis of SIGMAR1 variant (rs4879809) segregating in a consanguineous Pakistani family showing amyotrophic lateral sclerosis without frontotemporal lobar dementia. Neurogenetics 2015; 16:299-306. [PMID: 26205306 DOI: 10.1007/s10048-015-0453-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 07/02/2015] [Indexed: 02/07/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder affecting upper motor neurons in the brain and lower motor neurons in the brain stem and spinal cord, resulting in fatal paralysis. It has been found to be associated with frontotemporal lobar degeneration (FTLD). In the present study, we have described homozygosity mapping and gene sequencing in a consanguineous autosomal recessive Pakistani family showing non-juvenile ALS without signs of FTLD. Gene mapping was carried out in all recruited family members using microsatellite markers, and linkage was established with sigma non-opioid intracellular receptor 1 (SIGMAR1) gene at chromosome 9p13.2. Gene sequencing of SIGMAR1 revealed a novel 3'-UTR nucleotide variation c.672*31A>G (rs4879809) segregating with disease in this family. The C9ORF72 repeat region in intron 1, previously implicated in a related phenotype, was excluded through linkage, and further confirmation of exclusion was obtained by amplifying intron 1 of C9ORF72 with multiple primers in affected individuals and controls. In silico analysis was carried out to explore the possible role of 3'-UTR variant of SIGMAR1 in ALS. The Regulatory RNA motif and Element Finder program revealed disturbance in miRNA (hsa-miR-1205) binding site due to this variation. ESEFinder analysis showed new SRSF1 and SRSF1-IgM-BRCA1 binding sites with significant scores due to this variation. Our results indicate that the 3'-UTR SIGMAR1 variant c.672*31A>G may have a role in the pathogenesis of ALS in this family.
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Affiliation(s)
- Muhammad Ikram Ullah
- Department of Biochemistry, Faculty of Biological Sciences, Quaid i Azam University, Islamabad, 44000, Pakistan
- PCR and Research Laboratories, Shifa College of Medicine, Shifa Tameer e Millat University, Islamabad, 44000, Pakistan
| | - Arsalan Ahmad
- Division of Neurology, Shifa College of Medicine, Shifa International Hospital, Shifa Tameer e Millat University, Islamabad, 44000, Pakistan
| | - Syed Irfan Raza
- Department of Biochemistry, Faculty of Biological Sciences, Quaid i Azam University, Islamabad, 44000, Pakistan
| | - Ali Amar
- Department of Human Genetics and Molecular Biology, University of Health Sciences, Lahore, 54600, Pakistan
| | - Amjad Ali
- Atta ur Rahman School of Applied Biosciences (ASAB), National University of Sciences & Technology (NUST), Sector H-12, Islamabad, 44000, Pakistan
| | - Attya Bhatti
- Atta ur Rahman School of Applied Biosciences (ASAB), National University of Sciences & Technology (NUST), Sector H-12, Islamabad, 44000, Pakistan
| | - Peter John
- Atta ur Rahman School of Applied Biosciences (ASAB), National University of Sciences & Technology (NUST), Sector H-12, Islamabad, 44000, Pakistan
| | - Aisha Mohyuddin
- Section of Biochemistry, Shifa College of Medicine, Shifa Tameer e Millat University (STMU), Islamabad, 44000, Pakistan
| | - Wasim Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid i Azam University, Islamabad, 44000, Pakistan
| | - Muhammad Jawad Hassan
- Atta ur Rahman School of Applied Biosciences (ASAB), National University of Sciences & Technology (NUST), Sector H-12, Islamabad, 44000, Pakistan.
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13
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Mumtaz S, Yıldız E, Jabeen S, Khan A, Tolun A, Malik S. RBBP8 syndrome with microcephaly, intellectual disability, short stature and brachydactyly. Am J Med Genet A 2015; 167A:3148-52. [PMID: 26333564 DOI: 10.1002/ajmg.a.37299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 07/31/2015] [Indexed: 11/08/2022]
Abstract
Primary microcephaly is clinically variable and genetically heterogeneous. Four phenotypically distinct types of autosomal recessive microcephaly syndromes are due to different RBBP8 mutations. We report on a consanguineous Pakistani family with homozygous RBBP8 mutation c.1808_1809delTA (p.Ile603Lysfs*7) manifesting microcephaly and a distinct combination of skeletal, limb and ectodermal defects, mild intellectual disability, minor facial anomalies, anonychia, disproportionate short stature and brachydactyly, and additionally talipes in one patient.
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Affiliation(s)
- Sara Mumtaz
- Department of Animal Sciences, Human Genetics Program, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Esra Yıldız
- Department of Molecular Biology and Genetics, Boğaziçi University, Istanbul, Turkey
| | - Saliha Jabeen
- Department of Animal Sciences, Human Genetics Program, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Amjad Khan
- Department of Animal Sciences, Human Genetics Program, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Aslıhan Tolun
- Department of Molecular Biology and Genetics, Boğaziçi University, Istanbul, Turkey
| | - Sajid Malik
- Department of Animal Sciences, Human Genetics Program, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
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14
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Agha Z, Iqbal Z, Azam M, Siddique M, Willemsen MH, Kleefstra T, Zweier C, de Leeuw N, Qamar R, van Bokhoven H. A complex microcephaly syndrome in a Pakistani family associated with a novel missense mutation in RBBP8 and a heterozygous deletion in NRXN1. Gene 2014; 538:30-5. [PMID: 24440292 DOI: 10.1016/j.gene.2014.01.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 01/07/2014] [Accepted: 01/08/2014] [Indexed: 11/29/2022]
Abstract
We report on a consanguineous Pakistani family with a severe congenital microcephaly syndrome resembling the Seckel syndrome and Jawad syndrome. The affected individuals in this family were born to consanguineous parents of whom the mother presented with mild intellectual disability (ID), epilepsy and diabetes mellitus. The two living affected brothers presented with microcephaly, white matter disease of the brain, hyponychia, dysmorphic facial features with synophrys, epilepsy, diabetes mellitus and ID. Genotyping with a 250K SNP array in both affected brothers revealed an 18 MB homozygous region on chromosome 18 p11.21-q12.1 encompassing the SCKL2 locus of the Seckel and Jawad syndromes. Sequencing of the RBBP8 gene, underlying the Seckel and Jawad syndromes, identified the novel mutation c.919A>G, p.Arg307Gly, segregating in a recessive manner in the family. In addition, in the two affected brothers and their mother we have also found a heterozygous 607kb deletion, encompassing exons 13-19 of NRXN1. Bidirectional sequencing of the coding exons of NRXN1 did not reveal any other mutation on the other allele. It thus appears that the phenotype of the mildly affected mother can be explained by the NRXN1 deletion, whereas the more severe and complex microcephalic phenotype of the two affected brothers is due to the simultaneous deletion in NRXN1 and the homozygous missense mutation affecting RBBP8.
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Affiliation(s)
- Zehra Agha
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad, Pakistan; Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Zafar Iqbal
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Maleeha Azam
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | | | - Marjolein H Willemsen
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Tjitske Kleefstra
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Christiane Zweier
- Institute of Human Genetics, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Nicole de Leeuw
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Raheel Qamar
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad, Pakistan; Al-Nafees Medical College & Hospital, Isra University, Islamabad, Pakistan
| | - Hans van Bokhoven
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands; Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands.
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15
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Kumar A, Rajendran V, Sethumadhavan R, Purohit R. CEP proteins: the knights of centrosome dynasty. PROTOPLASMA 2013; 250:965-983. [PMID: 23456457 DOI: 10.1007/s00709-013-0488-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 02/12/2013] [Indexed: 06/01/2023]
Abstract
Centrosome forms the backbone of cell cycle progression mechanism. Recent debates have occurred regarding the essentiality of centrosome in cell cycle regulation. CEP family protein is the active component of centrosome and plays a vital role in centriole biogenesis and cell cycle progression control. A total of 31 proteins have been categorized into CEP family protein category and many more are under candidate evaluation. Furthermore, by the recent advancements in genomics and proteomics researches, several new CEP proteins have also been characterized. Here we have summarized the importance of CEP family proteins and their regulation mechanism involved in proper cell cycle progression. Further, we have reviewed the detailed molecular mechanism behind the associated pathological phenotypes and the possible therapeutic approaches. Proteins such as CEP57, CEP63, CEP152, CEP164, and CEP215 have been extensively studied with a detailed description of their molecular mechanisms, which are among the primary targets for drug discovery. Moreover, CEP27, CEP55, CEP70, CEP110, CEP120, CEP135, CEP192, CEP250, CEP290, and CEP350 also seem promising for future drug discovery approaches. Since the overview implicates that the overall researches on CEP proteins are not yet able to present significant details required for effective therapeutics development, thus, it is timely to discuss the importance of future investigations in this field.
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Affiliation(s)
- Ambuj Kumar
- Bioinformatics Division, School of Bio Sciences and Technology, Vellore Institute of Technology University, Vellore, 632014, Tamil Nadu, India
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16
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Abstract
Ataxia-telangiectasia (A-T) has for a long time stood apart from most other human neurodegenerative syndromes by the characteristic failure of cells derived from these patients to properly repair DNA damage-induced by ionizing radiation. The discovery of mutations in the ATM gene as being the underlying cause for A-T and the demonstration that the ATM protein functions as a DNA damage-responsive kinase has defined current research focusing on decoding how the cell responds to genotoxic stress. Yet, despite significant advances in delineating the cellular DNA damage response pathways coordinated by ATM, very little headway has been made toward understanding how loss of ATM leads to progressive cerebellar ataxia and whether this can be attributed to an underlying defect in DNA double strand break repair (DSBR). Since its identification, A-T has been used as the archetypal model for how a deficiency in DNA repair affects both the development and maintenance of the nervous and immune systems in humans as well as contributing to the process of tumourigenesis. However, following the growing availability and cost effectiveness of next generation sequencing technologies, the increasing recognition of novel human disorders associated with abnormal DNA repair has demonstrated that the neuropathology typified by A-T is an 'exception' rather than the 'rule'. As a consequence, this throws into doubt the longstanding hypothesis that the neurodegeneration seen in A-T is due to the progressive loss of damaged neurons that have acquired toxic levels of unrepaired DNA lesions over time. Therefore, this review aims to address the question: Is defective DNA double strand break repair an underlying cause of neurodegeneration?
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17
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Rambaud J, Marey I, Dupont C, Perrin-Sabourin L, Capri Y, Tabet AC, Benzacken B, Verloes A, Aboura A, Gérard M. Nail and phalangeal agenesis in a patient with 4pter and 9pter duplication. Am J Med Genet A 2012; 158A:2277-82. [PMID: 22821638 DOI: 10.1002/ajmg.a.35494] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 05/06/2012] [Indexed: 11/10/2022]
Abstract
We report on an 8-month-old girl with intra-uterine growth retardation, microcephaly, incomplete cleft lip, axial hypotonia, failure to thrive, and brachydactyly type B (phalangeal agenesis and absence of nails). She carried a supernumerary marker chromosome derived from chromosomes 4 and 9, leading to 4pter-q12 and 9pter-p21.2 duplication. The marker was derived from the 3:1 segregation of a maternal balanced translocation 46,XX, t(4;9)(q12;p21.2). The proposita is the first reported individual with distal phalangeal agenesis and anonychia, and trisomy 4p and partial trisomy 9p due to 3:1 segregation of a maternal reciprocal translocation.
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Affiliation(s)
- Jérôme Rambaud
- Department of Genetics, APHP Robert Debré University Hospital, Paris, France.
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18
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Qvist P, Huertas P, Jimeno S, Nyegaard M, Hassan MJ, Jackson SP, Børglum AD. CtIP Mutations Cause Seckel and Jawad Syndromes. PLoS Genet 2011; 7:e1002310. [PMID: 21998596 PMCID: PMC3188555 DOI: 10.1371/journal.pgen.1002310] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 07/30/2011] [Indexed: 11/18/2022] Open
Abstract
Seckel syndrome is a recessively inherited dwarfism disorder characterized by microcephaly and a unique head profile. Genetically, it constitutes a heterogeneous condition, with several loci mapped (SCKL1-5) but only three disease genes identified: the ATR, CENPJ, and CEP152 genes that control cellular responses to DNA damage. We previously mapped a Seckel syndrome locus to chromosome 18p11.31-q11.2 (SCKL2). Here, we report two mutations in the CtIP (RBBP8) gene within this locus that result in expression of C-terminally truncated forms of CtIP. We propose that these mutations are the molecular cause of the disease observed in the previously described SCKL2 family and in an additional unrelated family diagnosed with a similar form of congenital microcephaly termed Jawad syndrome. While an exonic frameshift mutation was found in the Jawad family, the SCKL2 family carries a splicing mutation that yields a dominant-negative form of CtIP. Further characterization of cell lines derived from the SCKL2 family revealed defective DNA damage induced formation of single-stranded DNA, a critical co-factor for ATR activation. Accordingly, SCKL2 cells present a lowered apoptopic threshold and hypersensitivity to DNA damage. Notably, over-expression of a comparable truncated CtIP variant in non-Seckel cells recapitulates SCKL2 cellular phenotypes in a dose-dependent manner. This work thus identifies CtIP as a disease gene for Seckel and Jawad syndromes and defines a new type of genetic disease mechanism in which a dominant negative mutation yields a recessively inherited disorder. Cellular DNA is frequently damaged through the actions of exogenous and endogenously arising DNA damaging agents. To maintain genome integrity, cells have evolved complex mechanisms to detect DNA damage, signal its presence, and mediate its repair. The importance of such mechanisms is evident because inherited defects in them can cause embryonic lethality or severe genetically inherited diseases. The clinical manifestations of such diseases are complex and include growth delay, mental retardation, skeletal abnormalities, and predisposition to cancer. While most such syndromes are inherited recessively, in some cases they are inherited dominantly. Here, we show that mutations in CtIP/RBBP8 cause related disorders: Seckel and Jawad syndromes. In addition to revealing how mutated CtIP impairs responses to DNA damage in Seckel cells, we establish that, despite the recessive mode of inheritance for this syndrome, the Seckel mutation has a dominant manifestation at the cellular level. To our knowledge, this represents a new form of molecular mechanism for recessive inheritance of a human disease. Furthermore, the aberrantly spliced mRNA is expressed at very low levels and yet significantly impairs cellular functions and causes severe clinical symptoms. This should provide new awareness that even very subtle splice mutations may have pronounced pathogenic potential.
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Affiliation(s)
- Per Qvist
- Department of Human Genetics and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Pablo Huertas
- The Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Departamento de Genética, Universidad de Sevilla, Sevilla, Spain
- * E-mail: (SPJ); (ADB); (PH)
| | - Sonia Jimeno
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Departamento de Genética, Universidad de Sevilla, Sevilla, Spain
| | - Mette Nyegaard
- Department of Human Genetics and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Muhammad J. Hassan
- Department of Biochemistry, Faculty of Biological Sciences, Quaid i Azam University, Islamabad, Pakistan
| | - Stephen P. Jackson
- The Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (SPJ); (ADB); (PH)
| | - Anders D. Børglum
- Department of Human Genetics and Department of Biomedicine, Aarhus University, Aarhus, Denmark
- * E-mail: (SPJ); (ADB); (PH)
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Tariq M, Khan MN, Ahmad W. Ectodermal dysplasia-cutaneous syndactyly syndrome maps to chromosome 7p21.1-p14.3. Hum Genet 2009; 125:421-9. [DOI: 10.1007/s00439-009-0640-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2008] [Accepted: 02/08/2009] [Indexed: 10/21/2022]
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