1
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Wesley CC, Levy DL. Differentiation-dependent changes in lamin B1 dynamics and lamin B receptor localization. Mol Biol Cell 2023; 34:ar10. [PMID: 36598800 PMCID: PMC9930530 DOI: 10.1091/mbc.e22-04-0137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The nuclear lamina serves important roles in chromatin organization and structural support, and lamina mutations can result in laminopathies. Less is known about how nuclear lamina structure changes during cellular differentiation-changes that may influence gene regulation. We examined the structure and dynamics of the nuclear lamina in human-induced pluripotent stem cells (iPSCs) and differentiated germ layer cells, focusing on lamin B1. We report that lamin B1 dynamics generally increase as iPSCs differentiate, especially in mesoderm and ectoderm, and that lamin B receptor (LBR) partially redistributes from the nucleus to cytoplasm in mesoderm. Knocking down LBR in iPSCs led to an increase in lamin B1 dynamics, a change that was not observed for ELYS, emerin, or lamin B2 knockdown. LBR knockdown also affected expression of differentiation markers. These data suggest that differentiation-dependent tethering of lamin B1 either directly by LBR or indirectly via LBR-chromatin associations impacts gene expression.
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Affiliation(s)
- Chase C. Wesley
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Daniel L. Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071,*Address correspondence to: Daniel L. Levy ()
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2
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Shen X, Li Z, Pan X, Yao J, Shen G, Zhang S, Dong M, Fan L. Prenatal diagnosis of recurrent moderate skeletal dysplasias in lamin B receptors. Front Genet 2023; 13:1020475. [PMID: 36712868 PMCID: PMC9883016 DOI: 10.3389/fgene.2022.1020475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/28/2022] [Indexed: 01/15/2023] Open
Abstract
The lamin B receptor (LBR) gene is located in chromosome 1q42.12 and encodes the lamin B receptor, an intracellular protein that binds to lamin B. LBR mutations are associated with a broad phenotypic spectrum ranging from non-lethal to lethal skeletal dysplasias. The typical phenotypes include the Pelger-Huet anomaly (PHA) and embryonic lethal Greenberg dysplasia (GRBGD). With the further study of this gene, other phenotypes have been found in different individuals. This retrospective study analyzed recurrent prenatal moderate skeletal dysplasias in Chinese fetuses. Nothing malformed was detected in the fetal karyotype and microarray, while the whole-exome sequencing identified a homozygous variant (NM_002296.4:c.1757G>A, NP_002287.2:p.Arg586His) in exon 14 of the LBR gene in both fetuses. Mutation analysis in the parents confirmed that the c.1757G>A variation is heterozygous by Sanger sequencing. Intensive analysis on bioinformatics and familial co-segregation suggest that the homozygous variation in the LBR gene is responsible for this recurrent prenatal moderate skeletal dysplasia. Moreover, moderate skeletal dysplasias differ from typical GRBGD phenotypes. Our findings are based on the DNA base test and the prenatal diagnosis of skeletal dysplasia, which can be helpful in proper phenotyping and contribute to a better understanding of the correlation between the phenotype and genotype.
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Affiliation(s)
- Xueping Shen
- Center of Prenatal Diagnosis, Huzhou Maternity & Child Healthcare Hospital, Huzhou, China
| | - Zhi Li
- Center of Prenatal Diagnosis, Huzhou Maternity & Child Healthcare Hospital, Huzhou, China
| | - Xuekui Pan
- Center of Prenatal Diagnosis, Huzhou Maternity & Child Healthcare Hospital, Huzhou, China
| | - Juan Yao
- Center of Prenatal Diagnosis, Huzhou Maternity & Child Healthcare Hospital, Huzhou, China
| | - Guosong Shen
- Center of Prenatal Diagnosis, Huzhou Maternity & Child Healthcare Hospital, Huzhou, China
| | - Su Zhang
- Center of Prenatal Diagnosis, Huzhou Maternity & Child Healthcare Hospital, Huzhou, China
| | - Minyue Dong
- Women’s Hospital, School of Medicine Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Genetics (Zhejiang University), Ministry of Education, Hangzhou, China
| | - Lihong Fan
- Center of Prenatal Diagnosis, Huzhou Maternity & Child Healthcare Hospital, Huzhou, China
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3
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Tsai PL, Cameron CJF, Forni MF, Wasko RR, Naughton BS, Horsley V, Gerstein MB, Schlieker C. Dynamic quality control machinery that operates across compartmental borders mediates the degradation of mammalian nuclear membrane proteins. Cell Rep 2022; 41:111675. [PMID: 36417855 PMCID: PMC9827541 DOI: 10.1016/j.celrep.2022.111675] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 09/15/2022] [Accepted: 10/26/2022] [Indexed: 11/23/2022] Open
Abstract
Many human diseases are caused by mutations in nuclear envelope (NE) proteins. How protein homeostasis and disease etiology are interconnected at the NE is poorly understood. Specifically, the identity of local ubiquitin ligases that facilitate ubiquitin-proteasome-dependent NE protein turnover is presently unknown. Here, we employ a short-lived, Lamin B receptor disease variant as a model substrate in a genetic screen to uncover key elements of NE protein turnover. We identify the ubiquitin-conjugating enzymes (E2s) Ube2G2 and Ube2D3, the membrane-resident ubiquitin ligases (E3s) RNF5 and HRD1, and the poorly understood protein TMEM33. RNF5, but not HRD1, requires TMEM33 both for efficient biosynthesis and function. Once synthesized, RNF5 responds dynamically to increased substrate levels at the NE by departing from the endoplasmic reticulum, where HRD1 remains confined. Thus, mammalian protein quality control machinery partitions between distinct cellular compartments to address locally changing substrate loads, establishing a robust cellular quality control system.
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Affiliation(s)
- Pei-Ling Tsai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Christopher J F Cameron
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT 06520, USA
| | - Maria Fernanda Forni
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Renee R Wasko
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Brigitte S Naughton
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Valerie Horsley
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Mark B Gerstein
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA; Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06511, USA; Department of Computer Science, Yale University, New Haven, CT 06511, USA; Department of Statistics and Data Science, Yale University, New Haven, CT 06511, USA
| | - Christian Schlieker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA; Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520, USA.
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4
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Borah S, Dhanasekaran K, Kumar S. The LEM-ESCRT toolkit: Repair and maintenance of the nucleus. Front Cell Dev Biol 2022; 10:989217. [PMID: 36172278 PMCID: PMC9512039 DOI: 10.3389/fcell.2022.989217] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/24/2022] [Indexed: 12/04/2022] Open
Abstract
The eukaryotic genome is enclosed in a nuclear envelope that protects it from potentially damaging cellular activities and physically segregates transcription and translation.Transport across the NE is highly regulated and occurs primarily via the macromolecular nuclear pore complexes.Loss of nuclear compartmentalization due to defects in NPC function and NE integrity are tied to neurological and ageing disorders like Alzheimer’s, viral pathogenesis, immune disorders, and cancer progression.Recent work implicates inner-nuclear membrane proteins of the conserved LEM domain family and the ESCRT machinery in NE reformation during cell division and NE repair upon rupture in migrating cancer cells, and generating seals over defective NPCs. In this review, we discuss the recent in-roads made into defining the molecular mechanisms and biochemical networks engaged by LEM and many other integral inner nuclear membrane proteins to preserve the nuclear barrier.
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Affiliation(s)
- Sapan Borah
- National Institute of Immunohaematology, Mumbai, Maharashtra, India
- *Correspondence: Sapan Borah, ; Karthigeyan Dhanasekaran, ; Santosh Kumar,
| | - Karthigeyan Dhanasekaran
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
- *Correspondence: Sapan Borah, ; Karthigeyan Dhanasekaran, ; Santosh Kumar,
| | - Santosh Kumar
- National Centre for Cell Science, Pune, Maharashtra, India
- *Correspondence: Sapan Borah, ; Karthigeyan Dhanasekaran, ; Santosh Kumar,
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5
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Oskarsson GR, Magnusson MK, Oddsson A, Jensson BO, Fridriksdottir R, Arnadottir GA, Katrinardottir H, Rognvaldsson S, Halldorsson GH, Sveinbjornsson G, Ivarsdottir EV, Stefansdottir L, Ferkingstad E, Norland K, Tragante V, Saemundsdottir J, Jonasdottir A, Jonasdottir A, Sigurjonsdottir S, Petursdottir KO, Davidsson OB, Rafnar T, Holm H, Olafsson I, Onundarson PT, Vidarsson B, Sigurdardottir O, Masson G, Gudbjartsson DF, Jonsdottir I, Norddahl GL, Thorsteinsdottir U, Sulem P, Stefansson K. Genetic architecture of band neutrophil fraction in Iceland. Commun Biol 2022; 5:525. [PMID: 35650273 PMCID: PMC9160026 DOI: 10.1038/s42003-022-03462-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 05/09/2022] [Indexed: 11/22/2022] Open
Abstract
The characteristic lobulated nuclear morphology of granulocytes is partially determined by composition of nuclear envelope proteins. Abnormal nuclear morphology is primarily observed as an increased number of hypolobulated immature neutrophils, called band cells, during infection or in rare envelopathies like Pelger-Huët anomaly. To search for sequence variants affecting nuclear morphology of granulocytes, we performed a genome-wide association study using band neutrophil fraction from 88,101 Icelanders. We describe 13 sequence variants affecting band neutrophil fraction at nine loci. Five of the variants are at the Lamin B receptor (LBR) locus, encoding an inner nuclear membrane protein. Mutations in LBR are linked to Pelger-Huët anomaly. In addition, we identify cosegregation of a rare stop-gain sequence variant in LBR and Pelger Huët anomaly in an Icelandic eight generation pedigree, initially reported in 1963. Two of the other loci include genes which, like LBR, play a role in the nuclear membrane function and integrity. These GWAS results highlight the role proteins of the inner nuclear membrane have as important for neutrophil nuclear morphology.
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Affiliation(s)
- Gudjon R Oskarsson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | - Magnus K Magnusson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland.
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.
| | | | | | | | | | | | | | | | | | | | | | | | | | - Vinicius Tragante
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Department of Cardiology, Division Heart and Lungs, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | | | | | | | | | | | | | | | - Hilma Holm
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
| | - Isleifur Olafsson
- Department of Clinical Biochemistry, Landspitali, The National University Hospital of Iceland, Reykjavik, Iceland
| | - Pall T Onundarson
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
- Department of Laboratory Hematology, Landspitali, The National University Hospital of Iceland, Reykjavik, Iceland
| | - Brynjar Vidarsson
- Department of Laboratory Hematology, Landspitali, The National University Hospital of Iceland, Reykjavik, Iceland
- The Laboratory in Mjodd, RAM, Reykjavik, Iceland
| | | | | | - Daniel F Gudbjartsson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
| | - Ingileif Jonsdottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
- Department of Immunology of Landspitali, The National University Hospital of Iceland, Reykjavik, Iceland
| | | | - Unnur Thorsteinsdottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | | | - Kari Stefansson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland.
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.
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6
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Evangelisti C, Rusciano I, Mongiorgi S, Ramazzotti G, Lattanzi G, Manzoli L, Cocco L, Ratti S. The wide and growing range of lamin B-related diseases: from laminopathies to cancer. Cell Mol Life Sci 2022; 79:126. [PMID: 35132494 PMCID: PMC8821503 DOI: 10.1007/s00018-021-04084-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/03/2021] [Accepted: 12/08/2021] [Indexed: 12/18/2022]
Abstract
B-type lamins are fundamental components of the nuclear lamina, a complex structure that acts as a scaffold for organization and function of the nucleus. Lamin B1 and B2, the most represented isoforms, are encoded by LMNB1 and LMNB2 gene, respectively. All B-type lamins are synthesized as precursors and undergo sequential post-translational modifications to generate the mature protein. B-type lamins are involved in a wide range of nuclear functions, including DNA replication and repair, regulation of chromatin and nuclear stiffness. Moreover, lamins B1 and B2 regulate several cellular processes, such as tissue development, cell cycle, cellular proliferation, senescence, and DNA damage response. During embryogenesis, B-type lamins are essential for organogenesis, in particular for brain development. As expected from the numerous and pivotal functions of B-type lamins, mutations in their genes or fluctuations in their expression levels are critical for the onset of several diseases. Indeed, a growing range of human disorders have been linked to lamin B1 or B2, increasing the complexity of the group of diseases collectively known as laminopathies. This review highlights the recent findings on the biological role of B-type lamins under physiological or pathological conditions, with a particular emphasis on brain disorders and cancer.
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Affiliation(s)
- Camilla Evangelisti
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Isabella Rusciano
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Sara Mongiorgi
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Giulia Ramazzotti
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Giovanna Lattanzi
- CNR Institute of Molecular Genetics "Luigi Luca Cavalli-Sforza", Unit of Bologna, Bologna, Italy
- IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Lucia Manzoli
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.
| | - Lucio Cocco
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.
| | - Stefano Ratti
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
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7
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Birks S, Uzer G. At the nuclear envelope of bone mechanobiology. Bone 2021; 151:116023. [PMID: 34051417 PMCID: PMC8600447 DOI: 10.1016/j.bone.2021.116023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 05/11/2021] [Accepted: 05/21/2021] [Indexed: 02/06/2023]
Abstract
The nuclear envelope and nucleoskeleton are emerging as signaling centers that regulate how physical information from the extracellular matrix is biochemically transduced into the nucleus, affecting chromatin and controlling cell function. Bone is a mechanically driven tissue that relies on physical information to maintain its physiological function and structure. Disorder that present with musculoskeletal and cardiac symptoms, such as Emery-Dreifuss muscular dystrophies and progeria, correlate with mutations in nuclear envelope proteins including Linker of Nucleoskeleton and Cytoskeleton (LINC) complex, Lamin A/C, and emerin. However, the role of nuclear envelope mechanobiology on bone function remains underexplored. The mesenchymal stem cell (MSC) model is perhaps the most studied relationship between bone regulation and nuclear envelope function. MSCs maintain the musculoskeletal system by differentiating into multiple cell types including osteocytes and adipocytes, thus supporting the bone's ability to respond to mechanical challenge. In this review, we will focus on how MSC function is regulated by mechanical challenges both in vitro and in vivo within the context of bone function specifically focusing on integrin, β-catenin and YAP/TAZ signaling. The importance of the nuclear envelope will be explored within the context of musculoskeletal diseases related to nuclear envelope protein mutations and nuclear envelope regulation of signaling pathways relevant to bone mechanobiology in vitro and in vivo.
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Affiliation(s)
- Scott Birks
- Boise State University, Micron School of Materials Science and Engineering, United States of America
| | - Gunes Uzer
- Boise State University, Mechanical and Biomedical Engineering, United States of America.
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8
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Pawar S, Kutay U. The Diverse Cellular Functions of Inner Nuclear Membrane Proteins. Cold Spring Harb Perspect Biol 2021; 13:a040477. [PMID: 33753404 PMCID: PMC8411953 DOI: 10.1101/cshperspect.a040477] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nuclear compartment is delimited by a specialized expanded sheet of the endoplasmic reticulum (ER) known as the nuclear envelope (NE). Compared to the outer nuclear membrane and the contiguous peripheral ER, the inner nuclear membrane (INM) houses a unique set of transmembrane proteins that serve a staggering range of functions. Many of these functions reflect the exceptional position of INM proteins at the membrane-chromatin interface. Recent research revealed that numerous INM proteins perform crucial roles in chromatin organization, regulation of gene expression, genome stability, and mediation of signaling pathways into the nucleus. Other INM proteins establish mechanical links between chromatin and the cytoskeleton, help NE remodeling, or contribute to the surveillance of NE integrity and homeostasis. As INM proteins continue to gain prominence, we review these advancements and give an overview on the functional versatility of the INM proteome.
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Affiliation(s)
- Sumit Pawar
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ulrike Kutay
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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9
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Turgut GT, Güleç Ç, Sarac Sivrikoz T, Kale H, Karaman B, Nishimura G, Altunoglu U. Antenatal diagnostic dilemma in a pseudodominant pedigree with lamin-B receptor (LBR)-related regressive spondylometaphyseal dysplasia. Am J Med Genet A 2021; 188:253-258. [PMID: 34467646 DOI: 10.1002/ajmg.a.62479] [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: 01/22/2021] [Revised: 08/11/2021] [Accepted: 08/15/2021] [Indexed: 11/07/2022]
Abstract
The lamin-B receptor (LBR) encodes a dual-functioning inner nuclear membrane protein essential for cholesterol biosynthesis and chromatin organization. LBR pathogenic variants cause distinct phenotypes due to the dual function of LBR, including Pelger-Huët anomaly (PHA), PHA with mild skeletal anomalies (PHASK; MIM# 618019), LBR-related regressive type of spondylometaphyseal dysplasia (LBR-R-SMD), Greenberg dysplasia (MIM# 215140). We here report the first case with radiological manifestations of LBR-R-SMD in the fetal period, and milder skeletal findings in the similarly affected father. Direct sequencing of LBR revealed homozygous c.1534C>T (p.Arg512Trp) in exon 12 in both affected individuals. Our report further refines the early phenotype in LBR-R-SMD, and demonstrates that the p.Arg512Trp mutation is associated with PHA. We propose that LBR-R-SMD should be considered as a differential diagnosis in pregnancies with sonographic evidence of short and bowed tubular bones with narrow thorax. Evaluating peripheral blood smears of expectant parents for the presence of PHA may lead to a clinical diagnosis, allowing for comprehensive prenatal genetic counseling.
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Affiliation(s)
- Gozde Tutku Turgut
- Department of Medical Genetics, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Çağrı Güleç
- Department of Medical Genetics, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Tugba Sarac Sivrikoz
- Department of Obstetrics and Gynecology, Division of Perinatology, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Hamdi Kale
- Department of Medical Genetics, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Birsen Karaman
- Department of Medical Genetics, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey.,Department of Pediatric Basic Sciences, Institute of Child Health, Istanbul University, Istanbul, Turkey
| | - Gen Nishimura
- Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Umut Altunoglu
- Department of Medical Genetics, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey.,Department of Medical Genetics, Koc University School of Medicine (KUSOM), Istanbul, Turkey
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10
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Young AN, Perlas E, Ruiz-Blanes N, Hierholzer A, Pomella N, Martin-Martin B, Liverziani A, Jachowicz JW, Giannakouros T, Cerase A. Deletion of LBR N-terminal domains recapitulates Pelger-Huet anomaly phenotypes in mouse without disrupting X chromosome inactivation. Commun Biol 2021; 4:478. [PMID: 33846535 PMCID: PMC8041748 DOI: 10.1038/s42003-021-01944-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 02/24/2021] [Indexed: 11/08/2022] Open
Abstract
Mutations in the gene encoding Lamin B receptor (LBR), a nuclear-membrane protein with sterol reductase activity, have been linked to rare human disorders. Phenotypes range from a benign blood disorder, such as Pelger-Huet anomaly (PHA), affecting the morphology and chromatin organization of white blood cells, to embryonic lethality as for Greenberg dysplasia (GRBGD). Existing PHA mouse models do not fully recapitulate the human phenotypes, hindering efforts to understand the molecular etiology of this disorder. Here we show, using CRISPR/Cas-9 gene editing technology, that a 236bp N-terminal deletion in the mouse Lbr gene, generating a protein missing the N-terminal domains of LBR, presents a superior model of human PHA. Further, we address recent reports of a link between Lbr and defects in X chromosome inactivation (XCI) and show that our mouse mutant displays minor X chromosome inactivation defects that do not lead to any overt phenotypes in vivo. We suggest that our N-terminal deletion model provides a valuable pre-clinical tool to the research community and will aid in further understanding the etiology of PHA and the diverse functions of LBR.
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Affiliation(s)
- Alexander Neil Young
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo (RM), Italy
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Emerald Perlas
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo (RM), Italy
| | - Nerea Ruiz-Blanes
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Andreas Hierholzer
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo (RM), Italy
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Nicola Pomella
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Belen Martin-Martin
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | | | - Joanna W Jachowicz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Thomas Giannakouros
- Laboratory of Biochemistry, Department of Chemistry, Aristotelian University, Thessaloniki, Greece
| | - Andrea Cerase
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo (RM), Italy.
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
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11
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Gatticchi L, de Las Heras JI, Sivakumar A, Zuleger N, Roberti R, Schirmer EC. Tm7sf2 Disruption Alters Radial Gene Positioning in Mouse Liver Leading to Metabolic Defects and Diabetes Characteristics. Front Cell Dev Biol 2020; 8:592573. [PMID: 33330474 PMCID: PMC7719783 DOI: 10.3389/fcell.2020.592573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/26/2020] [Indexed: 01/23/2023] Open
Abstract
Tissue-specific patterns of radial genome organization contribute to genome regulation and can be established by nuclear envelope proteins. Studies in this area often use cancer cell lines, and it is unclear how well such systems recapitulate genome organization of primary cells or animal tissues; so, we sought to investigate radial genome organization in primary liver tissue hepatocytes. Here, we have used a NET47/Tm7sf2–/– liver model to show that manipulating one of these nuclear membrane proteins is sufficient to alter tissue-specific gene positioning and expression. Dam-LaminB1 global profiling in primary liver cells shows that nearly all the genes under such positional regulation are related to/important for liver function. Interestingly, Tm7sf2 is a paralog of the HP1-binding nuclear membrane protein LBR that, like Tm7sf2, also has an enzymatic function in sterol reduction. Fmo3 gene/locus radial mislocalization could be rescued with human wild-type, but not TM7SF2 mutants lacking the sterol reductase function. One central pathway affected is the cholesterol synthesis pathway. Within this pathway, both Cyp51 and Msmo1 are under Tm7sf2 positional and expression regulation. Other consequences of the loss of Tm7sf2 included weight gain, insulin sensitivity, and reduced levels of active Akt kinase indicating additional pathways under its regulation, several of which are highlighted by mispositioning genes. This study emphasizes the importance for tissue-specific radial genome organization in tissue function and the value of studying genome organization in animal tissues and primary cells over cell lines.
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Affiliation(s)
- Leonardo Gatticchi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Jose I de Las Heras
- Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Aishwarya Sivakumar
- Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Nikolaj Zuleger
- Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Rita Roberti
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Eric C Schirmer
- Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
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12
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Molecular Genetics and Modifier Genes in Pseudoxanthoma Elasticum, a Heritable Multisystem Ectopic Mineralization Disorder. J Invest Dermatol 2020; 141:1148-1156. [PMID: 33341249 DOI: 10.1016/j.jid.2020.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 01/08/2023]
Abstract
In the past two decades, there has been great progress in identifying the molecular basis and pathomechanistic details in pseudoxanthoma elasticum (PXE), a heritable multisystem ectopic mineralization disorder. Although the identification of pathogenic variants in ABCC6 has been critical for understanding the disease process, genetic modifiers have been disclosed that explain the phenotypic heterogeneity of PXE. Adding to the genetic complexity of PXE are PXE-like phenotypes caused by pathogenic variants in other ectopic mineralization-associated genes. This review summarizes the current knowledge of the genetics and candidate modifier genes in PXE, a multifactorial disease at the genome-environment interface.
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Role of Metabolism in Bone Development and Homeostasis. Int J Mol Sci 2020; 21:ijms21238992. [PMID: 33256181 PMCID: PMC7729585 DOI: 10.3390/ijms21238992] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/22/2020] [Accepted: 11/25/2020] [Indexed: 02/07/2023] Open
Abstract
Carbohydrates, fats, and proteins are the underlying energy sources for animals and are catabolized through specific biochemical cascades involving numerous enzymes. The catabolites and metabolites in these metabolic pathways are crucial for many cellular functions; therefore, an imbalance and/or dysregulation of these pathways causes cellular dysfunction, resulting in various metabolic diseases. Bone, a highly mineralized organ that serves as a skeleton of the body, undergoes continuous active turnover, which is required for the maintenance of healthy bony components through the deposition and resorption of bone matrix and minerals. This highly coordinated event is regulated throughout life by bone cells such as osteoblasts, osteoclasts, and osteocytes, and requires synchronized activities from different metabolic pathways. Here, we aim to provide a comprehensive review of the cellular metabolism involved in bone development and homeostasis, as revealed by mouse genetic studies.
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Östlund C, Hernandez-Ono A, Shin JY. The Nuclear Envelope in Lipid Metabolism and Pathogenesis of NAFLD. BIOLOGY 2020; 9:biology9100338. [PMID: 33076344 PMCID: PMC7602593 DOI: 10.3390/biology9100338] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023]
Abstract
Simple Summary The liver is a major organ regulating lipid metabolism and a proper liver function is essential to health. Nonalcoholic fatty liver disease (NAFLD) is a condition with abnormal fat accumulation in the liver without heavy alcohol use. NAFLD is becoming one of the most common liver diseases with the increase in obesity in many parts of the world. There is no approved cure for the disease and a better understanding of disease mechanism is needed for effective prevention and treatment. The nuclear envelope, a membranous structure that surrounds the cell nucleus, is connected to the endoplasmic reticulum where the vast majority of cellular lipids are synthesized. Growing evidence indicates that components in the nuclear envelope are involved in cellular lipid metabolism. We review published studies with various cell and animal models, indicating the essential roles of nuclear envelope proteins in lipid metabolism. We also discuss how defects in these proteins affect cellular lipid metabolism and possibly contribute to the pathogenesis of NAFLD. Abstract Nonalcoholic fatty liver disease (NAFLD) is a burgeoning public health problem worldwide. Despite its tremendous significance for public health, we lack a comprehensive understanding of the pathogenic mechanisms of NAFLD and its more advanced stage, nonalcoholic steatohepatitis (NASH). Identification of novel pathways or cellular mechanisms that regulate liver lipid metabolism has profound implications for the understanding of the pathology of NAFLD and NASH. The nuclear envelope is topologically connected to the ER, where protein synthesis and lipid synthesis occurs. Emerging evidence points toward that the nuclear lamins and nuclear membrane-associated proteins are involved in lipid metabolism and homeostasis. We review published reports that link these nuclear envelope proteins to lipid metabolism. In particular, we focus on the recent work demonstrating the essential roles for the nuclear envelope-localized torsinA/lamina-associated polypeptide (LAP1) complex in hepatic steatosis, lipid secretion, and NASH development. We also discuss plausible pathogenic mechanisms by which the loss of either protein in hepatocytes leads to hepatic dyslipidemia and NASH development.
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Affiliation(s)
- Cecilia Östlund
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (C.Ö.); (A.H.-O.)
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Antonio Hernandez-Ono
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (C.Ö.); (A.H.-O.)
| | - Ji-Yeon Shin
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (C.Ö.); (A.H.-O.)
- Correspondence: ; Tel.: +1-212-305-4088
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15
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Gregersen PA, McKay V, Walsh M, Brown E, McGillivray G, Savarirayan R. A new case of Greenberg dysplasia and literature review suggest that Greenberg dysplasia, dappled diaphyseal dysplasia, and Astley-Kendall dysplasia are allelic disorders. Mol Genet Genomic Med 2020; 8:e1173. [PMID: 32304187 PMCID: PMC7284023 DOI: 10.1002/mgg3.1173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 01/30/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Greenberg dysplasia is a rare, autosomal recessive, prenatal lethal bone dysplasia caused by biallelic pathogenic variants in the lamin B receptor (LBR) gene. Pathogenic variants in LBR are also associated with Pelger-Huët anomaly, an autosomal dominant benign abnormality of the nuclear shape and chromatin organization of blood granulocytes, and Pelger-Huët anomaly with variable skeletal anomalies, a mild, regressing to moderate-severe autosomal recessive condition. Conditions with abnormal sterol metabolism and different genetic basis have clinical and radiographic features similar to Greenberg dysplasia, for example X-linked dominant chondrodysplasia punctata, Conradi-Hünermann type, and CHILD syndrome, and other conditions with unknown genetic etiology display very similar features, for example, dappled diaphyseal dysplasia and Astley-Kendall dysplasia. METHODS We present a fetus with typical clinical and radiographic features of Greenberg dysplasia, and review the literature. RESULTS Genetic testing confirmed the diagnosis Greenberg dysplasia: homozygosity for a pathogenic variant in LBR. CONCLUSION Comparing the clinical and radiographic phenotypes of Greenberg dysplasia, dappled diaphyseal dysplasia, and Astley-Kendall dysplasia, we suggest that these are allelic disorders.
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Affiliation(s)
- Pernille A. Gregersen
- Department of Clinical GeneticsAarhus University HospitalAarhusDenmark
- Pediatrics and Adolescent MedicineCentre for Rare DiseasesAarhus University HospitalAarhusDenmark
- Victorian Clinical Genetics ServicesThe Royal Children’s HospitalMelbourneVICAustralia
| | - Victoria McKay
- Department of Clinical GeneticsMerseyside and Cheshire Regional Clinical Genetics ServiceLiverpool Women’s NHS Foundation TrustLiverpoolUK
| | - Maie Walsh
- Victorian Clinical Genetics ServicesThe Royal Children’s HospitalMelbourneVICAustralia
- Victorian Clinical Genetics ServicesRoyal Melbourne HospitalMelbourneVICAustralia
| | - Erica Brown
- Victorian Clinical Genetics ServicesRoyal Women’s HospitalMelbourneVICAustralia
| | - George McGillivray
- Victorian Clinical Genetics ServicesThe Royal Children’s HospitalMelbourneVICAustralia
- Victorian Clinical Genetics ServicesRoyal Women’s HospitalMelbourneVICAustralia
- Murdoch Children’s Research InstituteUniversity of MelbourneParkvilleVICAustralia
| | - Ravi Savarirayan
- Victorian Clinical Genetics ServicesThe Royal Children’s HospitalMelbourneVICAustralia
- Murdoch Children’s Research InstituteUniversity of MelbourneParkvilleVICAustralia
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16
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Tang J, Zhou C, Shi H, Mo Y, Tan W, Sun T, Zhu J, Li Q, Li H, Li Y, Wang S, Hong Y, Li N, Zeng Q, Tan J, Ma W, Luo L. Prenatal diagnosis of skeletal dysplasias using whole exome sequencing in China. Clin Chim Acta 2020; 507:187-193. [PMID: 32360156 DOI: 10.1016/j.cca.2020.04.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 04/04/2020] [Accepted: 04/27/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND Skeletal dysplasias account for nearly 10% of fetal structural malformations detected by ultrasonography. This clinically heterogeneous group of genetic anomaly includes at least 461 genetic skeletal disorders with extreme clinical, phenotypic, and genetic heterogeneities, thus, significantly complicates accurate diagnosis. Researches have used whole exome sequencing (WES) for prenatal molecular diagnoses of skeletal dysplasias, however, data are still limited. METHODS DNA extracted from umbilical cord blood or amniocytes from fetuses suspected of skeletal dysplasias based on ultrasound evaluations were analyzed by WES. Blood samples were taken from the parents of the positive fetuses for co-segregation analysis using Sanger sequencing. RESULT Definitive molecular diagnosis was made in 6/8 (75%) cases, comprised of 5 de novo disease-causing changes in 3 genes (FGFR3, COL2A1, and COL1A2) and one proband with a biallelic deficiency for Lamin B Receptor(LBR),and including 3 novel variants. All fetuses had no detectable copy number variation (CNV) from sequencing results. CONCLUSIONS Our study suggests that WES is an efficient approach for prenatal diagnosis of fetuses suspected of skeletal abnormalities and contributes to parental genetics counseling and pregnancy management.
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Affiliation(s)
- Jia Tang
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China; Department of Medical Imaging Center, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, Guangdong 510080, China.
| | - Chenglong Zhou
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China; Halo Genetics, Guangzhou, Guangdong 510000, China
| | - Haihong Shi
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China; Halo Genetics, Guangzhou, Guangdong 510000, China
| | - Yuying Mo
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Weilan Tan
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Tielan Sun
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Jinling Zhu
- Department of Biology, School of Basic Medicine, Jiamusi University, Jiamusi, Heilongjiang 154007, China
| | - Qing Li
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Hui Li
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Yuping Li
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Songbai Wang
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Yan Hong
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Ning Li
- Halo Genetics, Guangzhou, Guangdong 510000, China
| | - Qinlong Zeng
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Jieliang Tan
- Medical Genetics Center, Jiangmen Maternity and Child Health Care Hospital, Jiangmen, Guangdong 529000, China
| | - Wei Ma
- Department of Biology, School of Basic Medicine, Jiamusi University, Jiamusi, Heilongjiang 154007, China
| | - Liangping Luo
- Department of Medical Imaging Center, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, Guangdong 510080, China.
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17
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Capell-Hattam IM, Sharpe LJ, Qian L, Hart-Smith G, Prabhu AV, Brown AJ. Twin enzymes, divergent control: The cholesterogenic enzymes DHCR14 and LBR are differentially regulated transcriptionally and post-translationally. J Biol Chem 2020; 295:2850-2865. [PMID: 31911440 PMCID: PMC7049974 DOI: 10.1074/jbc.ra119.011323] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/13/2019] [Indexed: 01/07/2023] Open
Abstract
Cholesterol synthesis is a tightly regulated process, both transcriptionally and post-translationally. Transcriptional control of cholesterol synthesis is relatively well-understood. However, of the ∼20 enzymes in cholesterol biosynthesis, post-translational regulation has only been examined for a small number. Three of the four sterol reductases in cholesterol production, 7-dehydrocholesterol reductase (DHCR7), 14-dehydrocholesterol reductase (DHCR14), and lamin-B receptor (LBR), share evolutionary ties with a high level of sequence homology and predicted structural homology. DHCR14 and LBR uniquely share the same Δ-14 reductase activity in cholesterol biosynthesis, yet little is known about their post-translational regulation. We have previously identified specific modes of post-translational control of DHCR7, but it is unknown whether these regulatory mechanisms are shared by DHCR14 and LBR. Using CHO-7 cells stably expressing epitope-tagged DHCR14 or LBR, we investigated the post-translational regulation of these enzymes. We found that DHCR14 and LBR undergo differential post-translational regulation, with DHCR14 being rapidly turned over, triggered by cholesterol and other sterol intermediates, whereas LBR remained stable. DHCR14 is degraded via the ubiquitin-proteasome system, and we identified several DHCR14 and DHCR7 putative interaction partners, including a number of E3 ligases that modulate DHCR14 levels. Interestingly, we found that gene expression across an array of human tissues showed a negative relationship between the C14-sterol reductases; one enzyme or the other tends to be predominantly expressed in each tissue. Overall, our findings indicate that whereas LBR tends to be the constitutively active C14-sterol reductase, DHCR14 levels are tunable, responding to the local cellular demands for cholesterol.
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Affiliation(s)
- Isabelle M Capell-Hattam
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Laura J Sharpe
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Lydia Qian
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Gene Hart-Smith
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia; Department of Molecular Sciences, Macquarie University, Macquarie Park, New South Wales 2109, Australia
| | - Anika V Prabhu
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia.
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18
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Capitanchik C, Dixon CR, Swanson SK, Florens L, Kerr ARW, Schirmer EC. Analysis of RNA-Seq datasets reveals enrichment of tissue-specific splice variants for nuclear envelope proteins. Nucleus 2019; 9:410-430. [PMID: 29912636 PMCID: PMC7000147 DOI: 10.1080/19491034.2018.1469351] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Laminopathies yield tissue-specific pathologies, yet arise from mutation of ubiquitously-expressed genes. A little investigated hypothesis to explain this is that the mutated proteins or their partners have tissue-specific splice variants. To test this, we analyzed RNA-Seq datasets, finding novel isoforms or isoform tissue-specificity for: Lap2, linked to cardiomyopathy; Nesprin 2, linked to Emery-Dreifuss muscular dystrophy and Lmo7, that regulates the Emery-Dreifuss muscular dystrophy linked emerin gene. Interestingly, the muscle-specific Lmo7 exon is rich in serine phosphorylation motifs, suggesting regulatory function. Muscle-specific splice variants in non-nuclear envelope proteins linked to other muscular dystrophies were also found. Nucleoporins tissue-specific variants were found for Nup54, Nup133, Nup153 and Nup358/RanBP2. RT-PCR confirmed novel Lmo7 and RanBP2 variants and specific knockdown of the Lmo7 variantreduced myogenic index. Nuclear envelope proteins were enriched for tissue-specific splice variants compared to the rest of the genome, suggesting that splice variants contribute to its tissue-specific functions.
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Affiliation(s)
- Charlotte Capitanchik
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Charles R Dixon
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Selene K Swanson
- b Stowers Institute for Medical Research , Kansas City , MO , USA
| | - Laurence Florens
- b Stowers Institute for Medical Research , Kansas City , MO , USA
| | - Alastair R W Kerr
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Eric C Schirmer
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
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19
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Giorgio E, Sirchia F, Bosco M, Sobreira NLM, Grosso E, Brussino A, Brusco A. A novel case of Greenberg dysplasia and genotype-phenotype correlation analysis for LBR pathogenic variants: An instructive example of one gene-multiple phenotypes. Am J Med Genet A 2019; 179:306-311. [PMID: 30561119 PMCID: PMC6349533 DOI: 10.1002/ajmg.a.61000] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/06/2018] [Accepted: 11/06/2018] [Indexed: 12/30/2022]
Abstract
Greenberg skeletal dysplasia is an autosomal recessive, perinatal lethal disorder associated with biallelic variants affecting the lamin B receptor (LBR) gene. LBR is also associated with the autosomal recessive anadysplasia-like spondylometaphyseal dysplasia, and the autosomal dominant Pelger-Huët anomaly, a benign laminopathy characterized by anomalies in the nuclear shape of blood granulocytes. The LBR is an inner nuclear membrane protein that binds lamin B proteins (LMNB1 and LMNB2), interacts with chromatin, and exerts a sterol reductase activity. Here, we report on a novel LBR missense variant [c.1379A>G; p.(D460R)], identified by whole exome sequencing and causing Greenberg dysplasia in two fetuses from a consanguineous Moroccan family. We revised published LBR variants to propose a genotype-phenotype correlation in LBR associated diseases. The diverse phenotypes are correlated to the functional domain affected, the heterozygous or homozygous state of the variants, and their different impact on the residual protein function. LBR represents an instructive example of one gene presenting with two different patterns of inheritance and at least three different clinical phenotypes.
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Affiliation(s)
- Elisa Giorgio
- University of Torino, Department of Medical Sciences, Torino, Italy
| | - Fabio Sirchia
- University of Trieste, IRCCS Burlo Garofalo, Department of Advanced Diagnostic and Clinical Trials Institute for Maternal Child Health, Trieste, Italy
| | - Martino Bosco
- San Lazzaro Hospital, Pathological Anatomy and Histology unit, Alba, Italy
| | - Nara Lygia M. Sobreira
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Johns Hopkins University School of Medicine, Department of Pediatrics, Baltimore, MD, USA
| | | | - Enrico Grosso
- Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Torino, Italy
| | | | - Alfredo Brusco
- University of Torino, Department of Medical Sciences, Torino, Italy
- Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Torino, Italy
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Wehrle A, Witkos TM, Schneider JC, Hoppmann A, Behringer S, Köttgen A, Elting M, Spranger J, Lowe M, Lausch E. A common pathomechanism in GMAP-210- and LBR-related diseases. JCI Insight 2018; 3:121150. [PMID: 30518689 PMCID: PMC6328090 DOI: 10.1172/jci.insight.121150] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 10/29/2018] [Indexed: 12/20/2022] Open
Abstract
Biallelic loss-of-function mutations in TRIP11, encoding the golgin GMAP-210, cause the lethal human chondrodysplasia achondrogenesis 1A (ACG1A). We now find that a homozygous splice-site mutation of the lamin B receptor (LBR) gene results in the same phenotype. Intrigued by the genetic heterogeneity, we compared GMAP-210- and LBR-deficient primary cells to unravel how particular mutations in LBR cause a phenocopy of ACG1A. We could exclude a regulatory interaction between LBR and GMAP-210 in patients' cells. However, we discovered a common disruption of Golgi apparatus architecture that was accompanied by decreased secretory trafficking in both cases. Deficiency of Golgi-dependent glycan processing indicated a similar downstream effect of the disease-causing mutations upon Golgi function. Unexpectedly, our results thus point to a common pathogenic mechanism in GMAP-210- and LBR-related diseases attributable to defective secretory trafficking at the Golgi apparatus.
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Affiliation(s)
- Anika Wehrle
- Department of Pediatrics, Medical Centre-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Tomasz M. Witkos
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Judith C. Schneider
- Department of Pediatrics, Medical Centre-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anselm Hoppmann
- Department of Pediatrics, Medical Centre-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute of Genetic Epidemiology, Medical Centre-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sidney Behringer
- Department of Pediatrics, Medical Centre-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anna Köttgen
- Institute of Genetic Epidemiology, Medical Centre-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Mariet Elting
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, Netherlands
| | - Jürgen Spranger
- Department of Pediatrics, Medical Centre-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Martin Lowe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Ekkehart Lausch
- Department of Pediatrics, Medical Centre-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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21
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You SH, Lee YS, Lee CP, Lin CP, Lin CY, Tsai CL, Chang YL, Cheng PJ, Wang TH, Chang SD. Identification of a c.544C>T mutation in WDR34 as a deleterious recessive allele of short rib-polydactyly syndrome. Taiwan J Obstet Gynecol 2018; 56:857-862. [PMID: 29241935 DOI: 10.1016/j.tjog.2017.10.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2017] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE Single-nucleotide polymorphism (SNP) microarrays and whole-exome sequencing (WES) are tools to precisely diagnose rare autosomal recessive (AR) diseases. In this study, SNP chip and WES were used to identify a mutated location in WDR34 in a baby born to consanguineous parents. CASE REPORT The baby, born at 36 gestational weeks had a small thoracic cage, symmetric short proximal bones, and polydactyly. Radiography showed short ribs with reduced lung volume and pulmonary opacities, compatible with asphyxiating thoracic dystrophy or short rib-polydactyly syndrome (SRPS). At 4 months of age, she died of pulmonary hypoplasia and sepsis. SNP microarray and evaluation tool confirmed WDR34 as the candidate gene. WES detected an AR mutation at c.554C > T [p.Arg182Trp] in WDR34. CONCLUSION This study was the first to identify c.544C > T [p.Arg182Trp] mutation in WDR34 in a patient with SRPS. According to the database, the homozygous mutation of c.544C > T in WDR34 was deleterious and the prevalence of heterozygous mutation was relatively higher in Asian population. More studies of this mutation in patients with SRPS are required.
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Affiliation(s)
- Shu-Han You
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Lin-Kou Medical Center, Tao-Yuan 333, Taiwan
| | - Yun-Shien Lee
- Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Tao-Yuan 333, Taiwan; Department of Biotechnology, Min-Chuan University, Tao-Yuan 333, Taiwan
| | - Chueh-Pai Lee
- Bioinformatics Division, Yourgene Bioscience Inc., New Taipei City, Taiwan
| | - Chih-Peng Lin
- Department of Biotechnology, Min-Chuan University, Tao-Yuan 333, Taiwan; Bioinformatics Division, Yourgene Bioscience Inc., New Taipei City, Taiwan
| | - Chiao-Yun Lin
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Lin-Kou Medical Center, Tao-Yuan 333, Taiwan; Gynecologic Cancer Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Chia-Lung Tsai
- Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Tao-Yuan 333, Taiwan
| | - Yao-Lung Chang
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Lin-Kou Medical Center, Tao-Yuan 333, Taiwan
| | - Po-Jen Cheng
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Lin-Kou Medical Center, Tao-Yuan 333, Taiwan
| | - Tzu-Hao Wang
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Lin-Kou Medical Center, Tao-Yuan 333, Taiwan; Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Tao-Yuan 333, Taiwan; College of Medicine, Chang Gung University, Tao-Yuan 333, Taiwan
| | - Shuenn-Dyh Chang
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Lin-Kou Medical Center, Tao-Yuan 333, Taiwan.
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22
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Perovanovic J, Hoffman EP. Mechanisms of allelic and clinical heterogeneity of lamin A/C phenotypes. Physiol Genomics 2018; 50:694-704. [PMID: 29750601 PMCID: PMC6335092 DOI: 10.1152/physiolgenomics.00128.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mutations in the lamin A/C (LMNA) gene cause a broad range of clinical syndromes that show tissue-restricted abnormalities of post mitotic tissues, such as muscle, nerve, heart, and adipose tissue. Mutations in other nuclear envelope proteins cause clinically overlapping disorders. The majority of mutations are dominant single amino acid changes (toxic protein produced by the single mutant gene), and patients are heterozygous with both normal and abnormal proteins. Experimental support has been provided for different models of cellular pathogenesis in nuclear envelope diseases, including changes in heterochromatin formation at the nuclear membrane (epigenomics), changes in the timing of steps during terminal differentiation of cells, and structural abnormalities of the nuclear membrane. These models are not mutually exclusive and may be important in different cells at different times of development. Recent experiments using fusion proteins of normal and mutant lamin A/C proteins fused to a bacterial adenine methyltransferase (DamID) provided compelling evidence of mutation-specific perturbation of epigenomic imprinting during terminal differentiation. These gain-of-function properties include lineage-specific ineffective genomic silencing during exit from the cell cycle (heterochromatinization), as well as promiscuous initiation of silencing at incorrect places in the genome. To date, these findings have been limited to a few muscular dystrophy and lipodystrophy LMNA mutations but seem shared with a distinct nuclear envelope disease, emerin-deficient muscular dystrophy. The dominant-negative structural model and gain-of-function epigenomic models for distinct LMNA mutations are not mutually exclusive, and it is likely that both models contribute to aspects of the many complex clinical phenotypes observed.
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Affiliation(s)
- Jelena Perovanovic
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health , Bethesda, Maryland
| | - Eric P Hoffman
- School of Pharmacy and Pharmaceutical Sciences, Binghamton University, State University of New York , Binghamton New York
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Brady GF, Kwan R, Cunha JB, Elenbaas JS, Omary MB. Lamins and Lamin-Associated Proteins in Gastrointestinal Health and Disease. Gastroenterology 2018; 154:1602-1619.e1. [PMID: 29549040 PMCID: PMC6038707 DOI: 10.1053/j.gastro.2018.03.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/04/2018] [Accepted: 03/06/2018] [Indexed: 02/07/2023]
Abstract
The nuclear lamina is a multi-protein lattice composed of A- and B-type lamins and their associated proteins. This protein lattice associates with heterochromatin and integral inner nuclear membrane proteins, providing links among the genome, nucleoskeleton, and cytoskeleton. In the 1990s, mutations in EMD and LMNA were linked to Emery-Dreifuss muscular dystrophy. Since then, the number of diseases attributed to nuclear lamina defects, including laminopathies and other disorders, has increased to include more than 20 distinct genetic syndromes. Studies of patients and mouse genetic models have pointed to important roles for lamins and their associated proteins in the function of gastrointestinal organs, including liver and pancreas. We review the interactions and functions of the lamina in relation to the nuclear envelope and genome, the ways in which its dysfunction is thought to contribute to human disease, and possible avenues for targeted therapies.
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Affiliation(s)
- Graham F. Brady
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,To whom correspondence should be addressed: University of Michigan Medical School, Division of Gastroenterology, Department of Internal Medicine, 1137 Catherine St., Ann Arbor, MI 48109-5622.
| | - Raymond Kwan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Juliana Bragazzi Cunha
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jared S. Elenbaas
- Medical Scientist Training Program, Washington University, St Louis, Missouri
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,Ǻbo Akademi University, Turku, Finland
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Hause F, Schlote D, Simm A, Hoffmann K, Santos AN. Accumulation of glycated proteins suggesting premature ageing in lamin B receptor deficient mice. Biogerontology 2018; 19:95-100. [PMID: 29081010 DOI: 10.1007/s10522-017-9733-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/19/2017] [Indexed: 01/01/2023]
Abstract
Accumulation of advanced glycation end products (AGEs) is accompanied by increased free radical activity which contributes to ageing and the development or worsening of degenerative diseases. Apart from other physiological factors, AGEs are also an important biomarker for premature ageing. Here we report protein modifications (glycation) in a mouse model of lamin B receptor deficient ic J /ic J mice displaying skin defects similar to those of classical progeria. Therefore, we analysed AGE-modifications in protein extracts from various tissues of ic J /ic J mice. Our results demonstrated that pentosidine as well as argpyrimidine were increased in ic J /ic J mice indicating a modification specific increase in biomarkers of ageing, especially derived from glycolysis dependent methylglyoxal. Furthermore, the expression of AGE-preventing enzymes (Glo1, Fn3k) differed between ic J /ic J and control mice. The results indicate that not only lamin A but also the lamin B receptor may be involved in ageing processes.
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Affiliation(s)
- Frank Hause
- Institute for Human Genetics, Martin Luther University of Halle-Wittenberg, 06112, Halle, Germany
| | - Dietmar Schlote
- Institute for Human Genetics, Martin Luther University of Halle-Wittenberg, 06112, Halle, Germany.
| | - Andreas Simm
- Clinic for Cardiac und Thoracic Surgery, Martin Luther University of Halle-Wittenberg, 06097, Halle, Germany
| | - Katrin Hoffmann
- Institute for Human Genetics, Martin Luther University of Halle-Wittenberg, 06112, Halle, Germany
| | - Alexander Navarrete Santos
- Clinic for Cardiac und Thoracic Surgery, Martin Luther University of Halle-Wittenberg, 06097, Halle, Germany
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Abstract
PURPOSE OF REVIEW Nuclear envelope links to a wide range of disorders, including several myopathies and neuropathies over the past 2 decades, has spurred research leading to a completely changed view of this important cellular structure and its functions. However, the many functions now assigned to the nuclear envelope make it increasingly hard to determine which functions underlie these disorders. RECENT FINDINGS New nuclear envelope functions in genome organization, regulation and repair, signaling, and nuclear and cellular mechanics have been added to its classical barrier function. Arguments can be made for any of these functions mediating abnormality in nuclear envelope disorders and data exist supporting many. Moreover, transient and/or distal nuclear envelope connections to other cellular proteins and structures may increase the complexity of these disorders. SUMMARY Although the increased understanding of nuclear envelope functions has made it harder to distinguish specific causes of nuclear envelope disorders, this is because it has greatly expanded the spectrum of possible mechanisms underlying them. This change in perspective applies well beyond the known nuclear envelope disorders, potentially implicating the nuclear envelope in a much wider range of myopathies and neuropathies.
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Zhang W, Taylor SP, Ennis HA, Forlenza KN, Duran I, Li B, Sanchez JAO, Nevarez L, Nickerson DA, Bamshad M, Lachman RS, Krakow D, Cohn DH. Expanding the genetic architecture and phenotypic spectrum in the skeletal ciliopathies. Hum Mutat 2018; 39:152-166. [PMID: 29068549 PMCID: PMC6198324 DOI: 10.1002/humu.23362] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/12/2017] [Accepted: 10/14/2017] [Indexed: 01/26/2023]
Abstract
Defects in the biosynthesis and/or function of primary cilia cause a spectrum of disorders collectively referred to as ciliopathies. A subset of these disorders is distinguished by profound abnormalities of the skeleton that include a long narrow chest with markedly short ribs, extremely short limbs, and polydactyly. These include the perinatal lethal short-rib polydactyly syndromes (SRPS) and the less severe asphyxiating thoracic dystrophy (ATD), Ellis-van Creveld (EVC) syndrome, and cranioectodermal dysplasia (CED) phenotypes. To identify new genes and define the spectrum of mutations in the skeletal ciliopathies, we analyzed 152 unrelated families with SRPS, ATD, and EVC. Causal variants were discovered in 14 genes in 120 families, including one newly associated gene and two genes previously associated with other ciliopathies. These three genes encode components of three different ciliary complexes; FUZ, which encodes a planar cell polarity complex molecule; TRAF3IP1, which encodes an anterograde ciliary transport protein; and LBR, which encodes a nuclear membrane protein with sterol reductase activity. The results established the molecular basis of SRPS type IV, in which mutations were identified in four different ciliary genes. The data provide systematic insight regarding the genotypes associated with a large cohort of these genetically heterogeneous phenotypes and identified new ciliary components required for normal skeletal development.
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Affiliation(s)
- Wenjuan Zhang
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California
| | - S Paige Taylor
- Department of Human Genetics, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California
| | - Hayley A Ennis
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California
| | - Kimberly N Forlenza
- Department of Orthopaedic Surgery, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California
| | - Ivan Duran
- Department of Orthopaedic Surgery, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California
- Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), University of Malaga, Malaga, Spain
| | - Bing Li
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California
| | - Jorge A Ortiz Sanchez
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California
| | - Lisette Nevarez
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, Washington
- University of Washington Center for Mendelian Genomics, University of Washington, Seattle, Washington
| | - Michael Bamshad
- Department of Genome Sciences, University of Washington, Seattle, Washington
- University of Washington Center for Mendelian Genomics, University of Washington, Seattle, Washington
- Department of Pediatrics, University of Washington, Seattle, Washington
- Division of Genetic Medicine, Seattle Children's Hospital, Seattle, Washington
| | - Ralph S Lachman
- International Skeletal Dysplasia Registry at UCLA, Los Angeles, California
| | - Deborah Krakow
- Department of Human Genetics, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California
- Department of Orthopaedic Surgery, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California
- International Skeletal Dysplasia Registry at UCLA, Los Angeles, California
- Department of Obstetrics and Gynecology, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California
| | - Daniel H Cohn
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California
- Department of Orthopaedic Surgery, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California
- International Skeletal Dysplasia Registry at UCLA, Los Angeles, California
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Nikolakaki E, Mylonis I, Giannakouros T. Lamin B Receptor: Interplay between Structure, Function and Localization. Cells 2017; 6:cells6030028. [PMID: 28858257 PMCID: PMC5617974 DOI: 10.3390/cells6030028] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/28/2017] [Accepted: 08/30/2017] [Indexed: 12/15/2022] Open
Abstract
Lamin B receptor (LBR) is an integral protein of the inner nuclear membrane, containing a hydrophilic N-terminal end protruding into the nucleoplasm, eight hydrophobic segments that span the membrane and a short, nucleoplasmic C-terminal tail. Two seemingly unrelated functions have been attributed to LBR. Its N-terminal domain tethers heterochromatin to the nuclear periphery, thus contributing to the shape of interphase nuclear architecture, while its transmembrane domains exhibit sterol reductase activity. Mutations within the transmembrane segments result in defects in cholesterol synthesis and are associated with diseases such as the Pelger–Huët anomaly and Greenberg skeletal dysplasia, whereas no such harmful mutations related to the anchoring properties of LBR have been reported so far. Recent evidence suggests a dynamic regulation of LBR expression levels, structural organization, localization and function, in response to various signals. The molecular mechanisms underlying this dynamic behavior have not yet been fully unraveled. Here, we provide an overview of the current knowledge of the interplay between the structure, function and localization of LBR, and hint at the interconnection of the two distinct functions of LBR.
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Affiliation(s)
- Eleni Nikolakaki
- Laboratory of Biochemistry, Department of Chemistry, Aristotelian University, Thessaloniki 54124, Greece.
| | - Ilias Mylonis
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Panepistimiou 3 BIOPOLIS, Larissa 41500, Greece.
| | - Thomas Giannakouros
- Laboratory of Biochemistry, Department of Chemistry, Aristotelian University, Thessaloniki 54124, Greece.
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Frisso G, Gelzo M, Procopio E, Sica C, Lenza MP, Dello Russo A, Donati MA, Salvatore F, Corso G. A rare case of sterol-C4-methyl oxidase deficiency in a young Italian male: Biochemical and molecular characterization. Mol Genet Metab 2017; 121:329-335. [PMID: 28673550 DOI: 10.1016/j.ymgme.2017.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/23/2017] [Accepted: 06/26/2017] [Indexed: 12/28/2022]
Abstract
Inborn defects of cholesterol biosynthesis are metabolic disorders presenting with multi-organ and tissue anomalies. An autosomal recessive defect involving the demethylating enzyme C4-methyl sterol (SC4MOL) has been reported in only 4 patients so far. In infancy, all patients were affected by microcephaly, bilateral congenital cataracts, growth delay, psoriasiform dermatitis, immune dysfunction, and intellectual disability. Herein, we describe a new case of SC4MOL deficiency in which a 19-year-old Italian male was affected by bilateral congenital cataracts, growth delay and learning disabilities, behavioral disorders and small stature, but not microcephaly. Our patient had abundant scalp dandruff, without other skin manifestations. Analysis of the blood sterol profile showed accumulation of C4-monomethyl and C4-dimethyl sterols suggesting a deficiency of the SC4MOL enzyme. Sequencing of the MSMO1 gene (also known as the "SC4MOL" gene) confirmed mutations in each allele (c.731A>G, p.Y244C, which is already known, and c.605G>A, p.G202E, which is a novel variant). His father carried c.731A>G mutation, whereas his mother carried c.605G>A. Thus, the combination of multiple skills and methodologies, in particular, blood sterol profiling and genetic analysis, led to the diagnosis of a new case of a very rare defect of cholesterol biosynthesis. Consequently, we suggest that these two analyses should be performed as soon as possible in all undiagnosed patients affected by bilateral cataracts and developmental delay.
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Affiliation(s)
- Giulia Frisso
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Via Sergio Pansini 5, 80131 Napoli, Italy; CEINGE Biotecnologie Avanzate s.c.a r.l., Via Gaetano Salvatore 486, 80145 Napoli, Italy
| | - Monica Gelzo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Via Sergio Pansini 5, 80131 Napoli, Italy
| | - Elena Procopio
- SOC Malattie Metaboliche e Muscolari Ereditarie, Centro di Eccellenza di Neuroscienze, Azienda Ospedaliero-Universitaria A. Meyer, Firenze, Italy
| | - Concetta Sica
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Via Sergio Pansini 5, 80131 Napoli, Italy
| | - Maria Pia Lenza
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Via Sergio Pansini 5, 80131 Napoli, Italy
| | - Antonio Dello Russo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Via Sergio Pansini 5, 80131 Napoli, Italy
| | - Maria Alice Donati
- SOC Malattie Metaboliche e Muscolari Ereditarie, Centro di Eccellenza di Neuroscienze, Azienda Ospedaliero-Universitaria A. Meyer, Firenze, Italy
| | - Francesco Salvatore
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Via Sergio Pansini 5, 80131 Napoli, Italy; CEINGE Biotecnologie Avanzate s.c.a r.l., Via Gaetano Salvatore 486, 80145 Napoli, Italy.
| | - Gaetano Corso
- Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Foggia, Viale L. Pinto 1, 71122 Foggia, Italy.
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29
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Giannios I, Chatzantonaki E, Georgatos S. Dynamics and Structure-Function Relationships of the Lamin B Receptor (LBR). PLoS One 2017; 12:e0169626. [PMID: 28118363 PMCID: PMC5261809 DOI: 10.1371/journal.pone.0169626] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 12/14/2016] [Indexed: 01/12/2023] Open
Abstract
The lamin B receptor (LBR) is a multi-spanning membrane protein of the inner nuclear membrane that is often employed as a "reporter" of nuclear envelope dynamics. We show here that the diffusional mobility of full-length LBR exhibits significant regional variation along the nuclear envelope, consistent with the existence of discrete LBR microdomains and the occurrence of multiple, asymmetrically-spaced anastomoses along the nuclear envelope-endoplasmic reticulum interface. Interestingly, a commonly used fusion protein that contains the amino-terminal region and the first transmembrane domain of LBR exhibits reduced mobility at the nuclear envelope, but behaves similarly to full-length LBR in the endoplasmic reticulum. On the other hand, carboxy-terminally truncated mutants that retain the first four transmembrane domains and a part or the whole of the amino-terminal region of LBR are generally hyper-mobile. These results suggest that LBR dynamics is structure and compartment specific. They also indicate that native LBR is probably "configured" by long-range interactions that involve the loops between adjacent transmembrane domains and parts of the amino-terminal region.
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Affiliation(s)
- Ioannis Giannios
- Stem Cell and Chromatin Group, The Institute of Molecular Biology and Biotechnology, Biomedical Division, FORTH-ITE, Heraklion, Crete, Greece
- The Laboratory of Biology, The University of Ioannina, School of Medicine, Ioannina, Greece
| | - Eleftheria Chatzantonaki
- Stem Cell and Chromatin Group, The Institute of Molecular Biology and Biotechnology, Biomedical Division, FORTH-ITE, Heraklion, Crete, Greece
- The Laboratory of Biology, The University of Ioannina, School of Medicine, Ioannina, Greece
| | - Spyros Georgatos
- Stem Cell and Chromatin Group, The Institute of Molecular Biology and Biotechnology, Biomedical Division, FORTH-ITE, Heraklion, Crete, Greece
- The Laboratory of Biology, The University of Ioannina, School of Medicine, Ioannina, Greece
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30
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Turner EM, Schlieker C. Pelger-Huët anomaly and Greenberg skeletal dysplasia: LBR-associated diseases of cholesterol metabolism. Rare Dis 2016; 4:e1241363. [PMID: 27830109 PMCID: PMC5077067 DOI: 10.1080/21675511.2016.1241363] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/02/2016] [Accepted: 09/21/2016] [Indexed: 12/23/2022] Open
Abstract
Lamin B Receptor (LBR) is an inner nuclear membrane protein associated with the rare human diseases Pelger-Huët anomaly and Greenberg skeletal dysplasia. A new study has used CRISPR/Cas9-mediated genetic manipulations in a human cell system to determine that the molecular etiology of these previously poorly understood disorders is a defect in cholesterol synthesis due to loss of LBR-associated sterol C14 reductase activity. The study furthermore determined that disease-associated LBR point mutations reduce sterol C14 reductase activity by decreasing the affinity of LBR for the reducing agent NADPH. Moreover, two disease-associated LBR truncation mutants were found to be highly unstable at the protein level and are rapidly turned over by a novel nuclear membrane-based protein quality control pathway. Thus, truncated LBR variants can now be used as model substrates for further investigations of nuclear protein quality control to uncover possible implications for other disease-associated nuclear envelopathies.
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Affiliation(s)
- Elizabeth M Turner
- Department of Molecular Biophysics & Biochemistry, Yale University , New Haven, CT, USA
| | - Christian Schlieker
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA; Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
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Abstract
The nucleus is separated from the cytosol by the nuclear envelope, which is a double lipid bilayer composed of the outer nuclear membrane and the inner nuclear membrane. The intermediate filament proteins lamin A, lamin B, and lamin C form a network underlying the inner nuclear membrane. This proteinaceous network provides the nucleus with its strength, rigidity, and elasticity. Positioned within the inner nuclear membrane are more than 150 inner nuclear membrane proteins, many of which interact directly with lamins and require lamins for their inner nuclear membrane localization. Inner nuclear membrane proteins and the nuclear lamins define the nuclear lamina. These inner nuclear membrane proteins have tissue-specific expression and diverse functions including regulating cytoskeletal organization, nuclear architecture, cell cycle dynamics, and genomic organization. Loss or mutations in lamins and inner nuclear membrane proteins cause a wide spectrum of diseases. Here, I will review the functions of the well-studied nuclear lamina proteins and the diseases associated with loss or mutations in these proteins. © 2016 American Physiological Society. Compr Physiol 6:1655-1674, 2016.
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Affiliation(s)
- James M. Holaska
- Department of Pharmaceutical Sciences, University of the Sciences, Philadelphia, Pennsylvania, USA
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32
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Tsai PL, Zhao C, Turner E, Schlieker C. The Lamin B receptor is essential for cholesterol synthesis and perturbed by disease-causing mutations. eLife 2016; 5:e16011. [PMID: 27336722 PMCID: PMC4951196 DOI: 10.7554/elife.16011] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 06/20/2016] [Indexed: 12/23/2022] Open
Abstract
Lamin B receptor (LBR) is a polytopic membrane protein residing in the inner nuclear membrane in association with the nuclear lamina. We demonstrate that human LBR is essential for cholesterol synthesis. LBR mutant derivatives implicated in Greenberg skeletal dysplasia or Pelger-Huët anomaly fail to rescue the cholesterol auxotrophy of a LBR-deficient human cell line, consistent with a loss-of-function mechanism for these congenital disorders. These disease-causing variants fall into two classes: point mutations in the sterol reductase domain perturb enzymatic activity by reducing the affinity for the essential cofactor NADPH, while LBR truncations render the mutant protein metabolically unstable, leading to its rapid degradation at the inner nuclear membrane. Thus, metabolically unstable LBR variants may serve as long-sought-after model substrates enabling previously impossible investigations of poorly understood protein turnover mechanisms at the inner nuclear membrane of higher eukaryotes.
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Affiliation(s)
- Pei-Ling Tsai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | - Chenguang Zhao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | - Elizabeth Turner
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | - Christian Schlieker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
- Department of Cell Biology, Yale School of Medicine, New Haven, United States
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Baumgart M, Wiśniewski M, Grzonkowska M, Małkowski B, Badura M, Szpinda M. Morphometric study of the neural ossification centers of the atlas and axis in the human fetus. Surg Radiol Anat 2016; 38:1205-1215. [PMID: 27142660 PMCID: PMC5104794 DOI: 10.1007/s00276-016-1681-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/25/2016] [Indexed: 11/16/2022]
Abstract
Purposes The knowledge of the developing cervical spine and its individual vertebrae, including their neural processes may be useful in the diagnostics of congenital vertebral malformations. This study was performed to quantitatively examine the neural ossification centers of the atlas and axis with respect to their linear, planar and volumetric parameters. Methods Using the methods of CT, digital-image analysis and statistics, the size of neural ossification centers in the atlas and axis in 55 spontaneously aborted human fetuses aged 17–30 weeks was studied. Results Without any male–female and right–left significant differences, the best fit growth dynamics for the neural ossification centers of the atlas and axis were, respectively, modelled by the following functions: for length: y = −13.461 + 6.140 × ln(age) ± 0.570 and y = −15.683 + 6.882 × ln(age) ± 0.503, for width: y = −4.006 + 1.930 × ln(age) ± 0.178 and y = −3.054 + 1.648 × ln(age) ± 0.178, for cross-sectional area: y = −7.362 + 0.780 × age ± 1.700 and y = −9.930 + 0.869 × age ± 1.911, and for volume: y = −6.417 + 0.836 × age ± 1.924 and y = −11.592 + 1.087 × age ± 2.509. Conclusions The size of neural ossification centers of the atlas and axis shows neither sexual nor bilateral differences. The neural ossification centers of the atlas and axis grow logarithmically in both length and width and linearly in both cross-sectional area and volume. The numerical data relating to the size of neural ossification centers of the atlas and axis derived from the CT and digital-image analysis are considered specific-age reference values of potential relevance in both the ultrasound monitoring and the early detection of spinal abnormalities relating to the neural processes of the first two cervical vertebrae in the fetus.
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Affiliation(s)
- Mariusz Baumgart
- Department of Normal Anatomy, The Ludwik Rydygier Collegium Medicum in Bydgoszcz, The Nicolaus Copernicus University in Toruń, Łukasiewicza 1 Street, 85-821, Bydgoszcz, Poland
| | - Marcin Wiśniewski
- Department of Normal Anatomy, The Ludwik Rydygier Collegium Medicum in Bydgoszcz, The Nicolaus Copernicus University in Toruń, Łukasiewicza 1 Street, 85-821, Bydgoszcz, Poland
| | - Magdalena Grzonkowska
- Department of Normal Anatomy, The Ludwik Rydygier Collegium Medicum in Bydgoszcz, The Nicolaus Copernicus University in Toruń, Łukasiewicza 1 Street, 85-821, Bydgoszcz, Poland
| | - Bogdan Małkowski
- Department of Positron Emission Tomography and Molecular Imaging, The Ludwik Rydygier Collegium Medicum in Bydgoszcz, The Nicolaus Copernicus University in Toruń, Łukasiewicza 1 Street, 85-821, Bydgoszcz, Poland
| | - Mateusz Badura
- Department of Normal Anatomy, The Ludwik Rydygier Collegium Medicum in Bydgoszcz, The Nicolaus Copernicus University in Toruń, Łukasiewicza 1 Street, 85-821, Bydgoszcz, Poland
| | - Michał Szpinda
- Department of Normal Anatomy, The Ludwik Rydygier Collegium Medicum in Bydgoszcz, The Nicolaus Copernicus University in Toruń, Łukasiewicza 1 Street, 85-821, Bydgoszcz, Poland.
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Radiographic features of the skeleton in disorders of post-squalene cholesterol biosynthesis. Pediatr Radiol 2015; 45:965-76. [PMID: 25646736 DOI: 10.1007/s00247-014-3257-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 11/05/2014] [Accepted: 11/26/2014] [Indexed: 01/26/2023]
Abstract
Disorders of post-squalene cholesterol biosynthesis are inborn errors of metabolism characterised by multiple congenital abnormalities, including significant skeletal involvement. The most frequent and best-characterised example is the Smith-Lemli-Opitz syndrome. Nine other disorders are known, namely autosomal-recessive Antley-Bixler syndrome, Greenberg dysplasia, X-linked dominant chondrodysplasia punctata, X-linked recessive male emopamil-binding protein deficiency, CHILD syndrome, CK syndrome, sterol C4 methyloxidase-like deficiency, desmosterolosis and lathosterolosis. This study provides an overview of the radiologic features observed in these diseases. A common pattern of limb abnormalities is recognisable, including polydactyly, which is typically post-axial and rarely interdigital and can involve all four limbs, and syndactyly of the toes. Chondrodysplasia punctata is specifically associated with a subgroup of disorders of cholesterol biosynthesis (Greenberg dysplasia, CHILD syndrome, X-linked dominant chondrodysplasia punctata, male emopamil-binding protein deficiency). The possible occurrence of epiphyseal stippling in the Smith-Lemli-Opitz syndrome, initially reported, does not appear to be confirmed. Stippling is also associated with other congenital disorders such as chromosomal abnormalities, brachytelephalangic chondrodysplasia punctata (X-linked recessive chondrodysplasia punctata, disruptions of vitamin K metabolism, maternal autoimmune diseases), rhizomelic chondrodysplasia punctata (peroxisomal disorders) and lysosomal storage disorders. In the differential diagnosis of epiphyseal stippling, a moth-eaten appearance of bones, asymmetry, or presence of a common pattern of limb abnormalities indicate inborn errors of cholesterol biosynthesis. We highlight the specific differentiating radiologic features of disorders of post-squalene cholesterol biosynthesis.
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35
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Worman HJ, Schirmer EC. Nuclear membrane diversity: underlying tissue-specific pathologies in disease? Curr Opin Cell Biol 2015; 34:101-12. [PMID: 26115475 PMCID: PMC4522394 DOI: 10.1016/j.ceb.2015.06.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 06/05/2015] [Accepted: 06/10/2015] [Indexed: 11/16/2022]
Abstract
Human 'laminopathy' diseases result from mutations in genes encoding nuclear lamins or nuclear envelope (NE) transmembrane proteins (NETs). These diseases present a seeming paradox: the mutated proteins are widely expressed yet pathology is limited to specific tissues. New findings suggest tissue-specific pathologies arise because these widely expressed proteins act in various complexes that include tissue-specific components. Diverse mechanisms to achieve NE tissue-specificity include tissue-specific regulation of the expression, mRNA splicing, signaling, NE-localization and interactions of potentially hundreds of tissue-specific NETs. New findings suggest these NETs underlie tissue-specific NE roles in cytoskeletal mechanics, cell-cycle regulation, signaling, gene expression and genome organization. This view of the NE as 'specialized' in each cell type is important to understand the tissue-specific pathology of NE-linked diseases.
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Affiliation(s)
- Howard J Worman
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, USA; Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, USA
| | - Eric C Schirmer
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.
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Platt FM, Wassif C, Colaco A, Dardis A, Lloyd-Evans E, Bembi B, Porter FD. Disorders of cholesterol metabolism and their unanticipated convergent mechanisms of disease. Annu Rev Genomics Hum Genet 2015; 15:173-94. [PMID: 25184529 DOI: 10.1146/annurev-genom-091212-153412] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Cholesterol plays a key role in many cellular processes, and is generated by cells through de novo biosynthesis or acquired from exogenous sources through the uptake of low-density lipoproteins. Cholesterol biosynthesis is a complex, multienzyme-catalyzed pathway involving a series of sequentially acting enzymes. Inherited defects in genes encoding cholesterol biosynthetic enzymes or other regulators of cholesterol homeostasis result in severe metabolic diseases, many of which are rare in the general population and currently without effective therapy. Historically, these diseases have been viewed as discrete disorders, each with its own genetic cause and distinct pathogenic cascades that lead to its specific clinical features. However, studies have recently shown that three of these diseases have an unanticipated mechanistic convergence. This surprising finding is not only shedding light on details of cellular cholesterol homeostasis but also suggesting novel approaches to therapy.
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Affiliation(s)
- Frances M Platt
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom;
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Gruenbaum Y, Foisner R. Lamins: nuclear intermediate filament proteins with fundamental functions in nuclear mechanics and genome regulation. Annu Rev Biochem 2015; 84:131-64. [PMID: 25747401 DOI: 10.1146/annurev-biochem-060614-034115] [Citation(s) in RCA: 368] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lamins are intermediate filament proteins that form a scaffold, termed nuclear lamina, at the nuclear periphery. A small fraction of lamins also localize throughout the nucleoplasm. Lamins bind to a growing number of nuclear protein complexes and are implicated in both nuclear and cytoskeletal organization, mechanical stability, chromatin organization, gene regulation, genome stability, differentiation, and tissue-specific functions. The lamin-based complexes and their specific functions also provide insights into possible disease mechanisms for human laminopathies, ranging from muscular dystrophy to accelerated aging, as observed in Hutchinson-Gilford progeria and atypical Werner syndromes.
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Affiliation(s)
- Yosef Gruenbaum
- Department of Genetics, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel;
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38
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Li X, Roberti R, Blobel G. Structure of an integral membrane sterol reductase from Methylomicrobium alcaliphilum. Nature 2015; 517:104-7. [PMID: 25307054 PMCID: PMC4285568 DOI: 10.1038/nature13797] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 08/26/2014] [Indexed: 01/04/2023]
Abstract
Sterols are essential biological molecules in the majority of life forms. Sterol reductases including Δ(14)-sterol reductase (C14SR, also known as TM7SF2), 7-dehydrocholesterol reductase (DHCR7) and 24-dehydrocholesterol reductase (DHCR24) reduce specific carbon-carbon double bonds of the sterol moiety using a reducing cofactor during sterol biosynthesis. Lamin B receptor (LBR), an integral inner nuclear membrane protein, also contains a functional C14SR domain. Here we report the crystal structure of a Δ(14)-sterol reductase (MaSR1) from the methanotrophic bacterium Methylomicrobium alcaliphilum 20Z (a homologue of human C14SR, LBR and DHCR7) with the cofactor NADPH. The enzyme contains ten transmembrane segments (TM1-10). Its catalytic domain comprises the carboxy-terminal half (containing TM6-10) and envelops two interconnected pockets, one of which faces the cytoplasm and houses NADPH, while the other one is accessible from the lipid bilayer. Comparison with a soluble steroid 5β-reductase structure suggests that the reducing end of NADPH meets the sterol substrate at the juncture of the two pockets. A sterol reductase activity assay proves that MaSR1 can reduce the double bond of a cholesterol biosynthetic intermediate, demonstrating functional conservation to human C14SR. Therefore, our structure as a prototype of integral membrane sterol reductases provides molecular insight into mutations in DHCR7 and LBR for inborn human diseases.
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Affiliation(s)
- Xiaochun Li
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Rita Roberti
- Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy
| | - Günter Blobel
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
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Sobreira N, Modaff P, Steel G, You J, Nanda S, Hoover-Fong J, Valle D, Pauli RM. An anadysplasia-like, spontaneously remitting spondylometaphyseal dysplasia secondary to lamin B receptor (LBR) gene mutations: further definition of the phenotypic heterogeneity of LBR-bone dysplasias. Am J Med Genet A 2015; 167A:159-63. [PMID: 25348816 PMCID: PMC4882113 DOI: 10.1002/ajmg.a.36808] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/11/2014] [Accepted: 09/11/2014] [Indexed: 11/09/2022]
Abstract
We describe a boy who has an anadysplasia-like spondylometaphyseal dysplasia. By whole exome sequencing he was shown to have compound heterozygous mutations of LBR that codes for the lamin B receptor. He shares many similarities with a case previously described, but in whom the early natural history could not be established [Borovik et al., 2013]. Thus, in addition to Greenberg dysplasia (a perinatal lethal disorder), homozygosity or compound heterozygosity of mutations in LBR can result in a mild, spontaneously regressing bone dysplasia.
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Affiliation(s)
- Nara Sobreira
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Peggy Modaff
- Midwest Regional Bone Dysplasia Clinic, Department of Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Gary Steel
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jing You
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Julie Hoover-Fong
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - David Valle
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Richard M Pauli
- Midwest Regional Bone Dysplasia Clinic, Department of Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin
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40
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An absence of nuclear lamins in keratinocytes leads to ichthyosis, defective epidermal barrier function, and intrusion of nuclear membranes and endoplasmic reticulum into the nuclear chromatin. Mol Cell Biol 2014; 34:4534-44. [PMID: 25312645 DOI: 10.1128/mcb.00997-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
B-type lamins (lamins B1 and B2) have been considered to be essential for many crucial functions in the cell nucleus (e.g., DNA replication and mitotic spindle formation). However, this view has been challenged by the observation that an absence of both B-type lamins in keratinocytes had no effect on cell proliferation or the development of skin and hair. The latter findings raised the possibility that the functions of B-type lamins are subserved by lamins A and C. To explore that idea, we created mice lacking all nuclear lamins in keratinocytes. Those mice developed ichthyosis and a skin barrier defect, which led to death from dehydration within a few days after birth. Microscopy of nuclear-lamin-deficient skin revealed hyperkeratosis and a disordered stratum corneum with an accumulation of neutral lipid droplets; however, BrdU incorporation into keratinocytes was normal. Skin grafting experiments confirmed the stratum corneum abnormalities and normal BrdU uptake. Interestingly, the absence of nuclear lamins in keratinocytes resulted in an interspersion of nuclear/endoplasmic reticulum membranes with the chromatin. Thus, a key function of the nuclear lamina is to serve as a "fence" and prevent the incursion of cytoplasmic organelles into the nuclear chromatin.
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Affiliation(s)
- Pierre Deshuillers
- Department of Comparative Pathobiology; Purdue University College of Veterinary Medicine; West Lafayette IN USA
| | - Rose Raskin
- Department of Comparative Pathobiology; Purdue University College of Veterinary Medicine; West Lafayette IN USA
| | - Joanne Messick
- Department of Comparative Pathobiology; Purdue University College of Veterinary Medicine; West Lafayette IN USA
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Abstract
In eukaryotes, the function of the cell's nucleus has primarily been considered to be the repository for the organism's genome. However, this rather simplistic view is undergoing a major shift, as it is increasingly apparent that the nucleus has functions extending beyond being a mere genome container. Recent findings have revealed that the structural composition of the nucleus changes during development and that many of these components exhibit cell- and tissue-specific differences. Increasing evidence is pointing to the nucleus being integral to the function of the interphase cytoskeleton, with changes to nuclear structural proteins having ramifications affecting cytoskeletal organization and the cell's interactions with the extracellular environment. Many of these functions originate at the nuclear periphery, comprising the nuclear envelope (NE) and underlying lamina. Together, they may act as a "hub" in integrating cellular functions including chromatin organization, transcriptional regulation, mechanosignaling, cytoskeletal organization, and signaling pathways. Interest in such an integral role has been largely stimulated by the discovery that many diseases and anomalies are caused by defects in proteins of the NE/lamina, the nuclear envelopathies, many of which, though rare, are providing insights into their more common variants that are some of the major issues of the twenty-first century public health. Here, we review the contributions that mouse mutants have made to our current understanding of the NE/lamina, their respective roles in disease and the use of mice in developing potential therapies for treating the diseases.
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43
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Stancheva I, Schirmer EC. Nuclear Envelope: Connecting Structural Genome Organization to Regulation of Gene Expression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 773:209-44. [DOI: 10.1007/978-1-4899-8032-8_10] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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44
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Wazir U, Ahmed MH, Bridger JM, Harvey A, Jiang WG, Sharma AK, Mokbel K. The clinicopathological significance of lamin A/C, lamin B1 and lamin B receptor mRNA expression in human breast cancer. Cell Mol Biol Lett 2013; 18:595-611. [PMID: 24293108 PMCID: PMC6275779 DOI: 10.2478/s11658-013-0109-9] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 11/25/2013] [Indexed: 12/26/2022] Open
Abstract
Lamin A/C (LMNA), lamin B1 (LMNB1) and lamin B receptor (LBR) have key roles in nuclear structural integrity and chromosomal stability. In this study, we have studied the relationships between the mRNA expressions of A-type lamins, LMNB1 and LBR and the clinicopathological parameters in human breast cancer. Samples of breast cancer tissues (n = 115) and associated non-cancerous tissue (ANCT; n = 30) were assessed using reverse transcription and quantitative PCR. Transcript levels were correlated with clinicopathological data. Higher levels of A-type lamins and LMNB1 mRNA expression were seen in ANCT. Higher lamin A/C expression was associated with the early clinical stage (TNM1 vs. TNM3 - 13 vs. 0.21; p = 0.0515), with better clinical outcomes (disease-free survival vs. mortality - 11 vs. 1; p = 0.0326), and with better overall (p = 0.004) and disease-free survival (p = 0.062). The expression of LMNB1 declined with worsening clinical outcome (disease-free vs. mortalities - 0.0011 vs. 0.000; p = 0.0177). LBR mRNA expression was directly associated with tumor grade (grade 1 vs. grade 3 - 0.00 vs. 0.00; p = 0.0479) and Nottingham Prognostic Index (NPI1 vs. NPI3 - 0.00 vs. 0.00; p = 0.0551). To the best of our knowledge, this is the first study to suggest such a role for A-type lamins, lamin B1 and LBR in human breast cancer, identifying an important area for further research.
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Affiliation(s)
- Umar Wazir
- The London Breast Institute, Princess Grace Hospital, London, UK
- Department of Breast Surgery, St. George’s Hospital and Medical School, University of London, London, UK
| | - Mai Hassan Ahmed
- Centre for Cell & Chromosome Biology, Uxbridge, London, UK
- Brunel Institute for Cancer Genetics and Pharmacogenomics, School of Health Sciences and Social Care, Brunel University, Uxbridge, London, UK
| | | | - Amanda Harvey
- Brunel Institute for Cancer Genetics and Pharmacogenomics, School of Health Sciences and Social Care, Brunel University, Uxbridge, London, UK
| | - Wen G. Jiang
- Metastasis and Angiogenesis Research Group, University Department of Surgery, Cardiff University School of Medicine, Cardiff University, Cardiff, Wales, UK
| | - Anup K. Sharma
- The London Breast Institute, Princess Grace Hospital, London, UK
| | - Kefah Mokbel
- London Breast Institute, the Princess Grace Hospital, 45 Nottingham Place, London, W1U 5NY UK
- The London Breast Institute, Princess Grace Hospital, London, UK
- Department of Breast Surgery, St. George’s Hospital and Medical School, University of London, London, UK
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45
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de Las Heras JI, Meinke P, Batrakou DG, Srsen V, Zuleger N, Kerr AR, Schirmer EC. Tissue specificity in the nuclear envelope supports its functional complexity. Nucleus 2013; 4:460-77. [PMID: 24213376 PMCID: PMC3925691 DOI: 10.4161/nucl.26872] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Nuclear envelope links to inherited disease gave the conundrum of how mutations in near-ubiquitous proteins can yield many distinct pathologies, each focused in different tissues. One conundrum-resolving hypothesis is that tissue-specific partner proteins mediate these pathologies. Such partner proteins may have now been identified with recent proteome studies determining nuclear envelope composition in different tissues. These studies revealed that the majority of the total nuclear envelope proteins are tissue restricted in their expression. Moreover, functions have been found for a number these tissue-restricted nuclear envelope proteins that fit with mechanisms proposed to explain how the nuclear envelope could mediate disease, including defects in mechanical stability, cell cycle regulation, signaling, genome organization, gene expression, nucleocytoplasmic transport, and differentiation. The wide range of functions to which these proteins contribute is consistent with not only their involvement in tissue-specific nuclear envelope disease pathologies, but also tissue evolution.
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Affiliation(s)
- Jose I de Las Heras
- Wellcome Trust Centre for Cell Biology and Institute of Cell Biology; University of Edinburgh; Edinburgh, UK
| | - Peter Meinke
- Wellcome Trust Centre for Cell Biology and Institute of Cell Biology; University of Edinburgh; Edinburgh, UK
| | - Dzmitry G Batrakou
- Wellcome Trust Centre for Cell Biology and Institute of Cell Biology; University of Edinburgh; Edinburgh, UK
| | - Vlastimil Srsen
- Wellcome Trust Centre for Cell Biology and Institute of Cell Biology; University of Edinburgh; Edinburgh, UK
| | - Nikolaj Zuleger
- Wellcome Trust Centre for Cell Biology and Institute of Cell Biology; University of Edinburgh; Edinburgh, UK
| | - Alastair Rw Kerr
- Wellcome Trust Centre for Cell Biology and Institute of Cell Biology; University of Edinburgh; Edinburgh, UK
| | - Eric C Schirmer
- Wellcome Trust Centre for Cell Biology and Institute of Cell Biology; University of Edinburgh; Edinburgh, UK
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Borovik L, Modaff P, Waterham HR, Krentz AD, Pauli RM. Pelger-huet anomaly and a mild skeletal phenotype secondary to mutations in LBR. Am J Med Genet A 2013; 161A:2066-73. [PMID: 23824842 DOI: 10.1002/ajmg.a.36019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 04/01/2013] [Indexed: 01/02/2023]
Abstract
The Lamin B receptor (LBR) gene has been described to encode a bifunctional protein. Mutations in the LBR gene can affect neutrophil segmentation and sterol reductase activity and have been associated with two different recognized clinical conditions, Pelger-Huet anomaly (PHA) and Greenberg skeletal dysplasia. PHA is a benign autosomal co-dominant laminopathy resulting in bilobed neutrophil nuclei in heterozygotes, and unsegmented (ovoid) neutrophil nuclei in homozygotes. Some putative PHA homozygotes have been reported with minor skeletal malformations. Greenberg skeletal dysplasia is a severe autosomal recessive, perinatal lethal dwarfing disorder in which heterozygous carriers are usually without clinical manifestations. We here report a girl who has bilobed neutrophil nuclei and a mild skeletal dysplasia. Mutation analysis showed two novel mutations in the LBR gene: c.651_653 delinsTGATGAGAAA (p.Ile218Aspfs*19) and c.1757G > A (p.Arg586His). These mutations were found to be in trans, and, thus, she is a compound heterozygote. Sterol analysis found trace amounts of cholesta-8,14-dien-3beta-ol, which is normally undetected in healthy individuals. This and previously reported cases suggest that mutations in LBR can result in a continuum of phenotypic manifestations.
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Affiliation(s)
- Lior Borovik
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53705, USA
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47
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Schreiber KH, Kennedy BK. When lamins go bad: nuclear structure and disease. Cell 2013; 152:1365-75. [PMID: 23498943 DOI: 10.1016/j.cell.2013.02.015] [Citation(s) in RCA: 286] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Indexed: 12/17/2022]
Abstract
Mutations in nuclear lamins or other proteins of the nuclear envelope are the root cause of a group of phenotypically diverse genetic disorders known as laminopathies, which have symptoms that range from muscular dystrophy to neuropathy to premature aging syndromes. Although precise disease mechanisms remain unclear, there has been substantial progress in our understanding of not only laminopathies, but also the biological roles of nuclear structure. Nuclear envelope dysfunction is associated with altered nuclear activity, impaired structural dynamics, and aberrant cell signaling. Building on these findings, small molecules are being discovered that may become effective therapeutic agents.
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Lubala TK, Lubala N, Munkana AN, Nyenga AM, Mutombo AM. Greenberg Skeletal Dysplasia: first reported case in the Democratic Republic of Congo. Pan Afr Med J 2013; 14:55. [PMID: 23565302 PMCID: PMC3617618 DOI: 10.11604/pamj.2013.14.55.2170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 12/09/2012] [Indexed: 11/17/2022] Open
Abstract
We describe the first Congolese case of Greenberg Skeletal Dysplasia. Were noted at birth a congenital hydrops, a chondrodystrophy, a severe hypoplastic face as well as an ulnar (postaxial) hexadactyly on all four limbs.
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Affiliation(s)
- Toni Kasole Lubala
- Faculté de Médecine, Université de Lubumbashi, 1825 Lubumbashi, Democratic Republic of Congo
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49
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Ačimovič J, Rozman D. Steroidal triterpenes of cholesterol synthesis. Molecules 2013; 18:4002-17. [PMID: 23558541 PMCID: PMC6269928 DOI: 10.3390/molecules18044002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 03/19/2013] [Accepted: 03/27/2013] [Indexed: 11/21/2022] Open
Abstract
Cholesterol synthesis is a ubiquitous and housekeeping metabolic pathway that leads to cholesterol, an essential structural component of mammalian cell membranes, required for proper membrane permeability and fluidity. The last part of the pathway involves steroidal triterpenes with cholestane ring structures. It starts by conversion of acyclic squalene into lanosterol, the first sterol intermediate of the pathway, followed by production of 20 structurally very similar steroidal triterpene molecules in over 11 complex enzyme reactions. Due to the structural similarities of sterol intermediates and the broad substrate specificity of the enzymes involved (especially sterol-Δ24-reductase; DHCR24) the exact sequence of the reactions between lanosterol and cholesterol remains undefined. This article reviews all hitherto known structures of post-squalene steroidal triterpenes of cholesterol synthesis, their biological roles and the enzymes responsible for their synthesis. Furthermore, it summarises kinetic parameters of enzymes (Vmax and Km) and sterol intermediate concentrations from various tissues. Due to the complexity of the post-squalene cholesterol synthesis pathway, future studies will require a comprehensive meta-analysis of the pathway to elucidate the exact reaction sequence in different tissues, physiological or disease conditions. A major reason for the standstill of detailed late cholesterol synthesis research was the lack of several steroidal triterpene standards. We aid to this efforts by summarizing commercial and laboratory standards, referring also to chemical syntheses of meiosis-activating sterols.
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Affiliation(s)
- Jure Ačimovič
- Centre for Functional Genomics and Bio-Chips, Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Zaloška 4, Ljubljana SI-1000, Slovenia.
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50
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Clever M, Mimura Y, Funakoshi T, Imamoto N. Regulation and coordination of nuclear envelope and nuclear pore complex assembly. Nucleus 2013; 4:105-14. [PMID: 23412657 PMCID: PMC3621742 DOI: 10.4161/nucl.23796] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In metazoans with “open” mitosis, cells undergo structural changes involving the complete disassembly of the nuclear envelope (NE). In post-mitosis, the dividing cell faces the difficulty to reassemble NE structures in a highly regulated fashion around separated chromosomes. The de novo formation of nuclear pore complexes (NPCs), which are gateways between the cytoplasm and nucleoplasm across the nuclear membrane, is an archetype of macromolecular assembly and is therefore of special interest. The reformation of a functional NE further involves the reassembly and organization of other NE components, the nuclear membrane and NE proteins, around chromosomes in late mitosis.
Here, we discuss the function of NE components, such as lamins and INM proteins, in NE reformation and highlight recent results on coordination of NPC and NE assembly.
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Affiliation(s)
- Michaela Clever
- Cellular Dynamics Laboratory, RIKEN Advanced Science Institute 2-1 Hirosawa, Wako, Japan
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