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Tantry MSA, Santhakumar K. Insights on the Role of α- and β-Tubulin Isotypes in Early Brain Development. Mol Neurobiol 2023; 60:3803-3823. [PMID: 36943622 DOI: 10.1007/s12035-023-03302-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 03/05/2023] [Indexed: 03/23/2023]
Abstract
Tubulins are the highly conserved subunit of microtubules which involve in various fundamental functions including brain development. Microtubules help in neuronal proliferation, migration, differentiation, cargo transport along the axons, synapse formation, and many more. Tubulin gene family consisting of multiple isotypes, their differential expression and varied post translational modifications create a whole new level of complexity and diversity in accomplishing manifold neuronal functions. The studies on the relation between tubulin genes and brain development opened a new avenue to understand the role of each tubulin isotype in neurodevelopment. Mutations in tubulin genes are reported to cause brain development defects especially cortical malformations, referred as tubulinopathies. There is an increased need to understand the molecular correlation between various tubulin mutations and the associated brain pathology. Recently, mutations in tubulin isotypes (TUBA1A, TUBB, TUBB1, TUBB2A, TUBB2B, TUBB3, and TUBG1) have been linked to cause various neurodevelopmental defects like lissencephaly, microcephaly, cortical dysplasia, polymicrogyria, schizencephaly, subcortical band heterotopia, periventricular heterotopia, corpus callosum agenesis, and cerebellar hypoplasia. This review summarizes on the microtubule dynamics, their role in neurodevelopment, tubulin isotypes, post translational modifications, and the role of tubulin mutations in causing specific neurodevelopmental defects. A comprehensive list containing all the reported tubulin pathogenic variants associated with brain developmental defects has been prepared to give a bird's eye view on the broad range of tubulin functions.
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Affiliation(s)
- M S Ananthakrishna Tantry
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, 603203, India
| | - Kirankumar Santhakumar
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, 603203, India.
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2
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Attard TJ, Welburn JPI, Marsh JA. Understanding molecular mechanisms and predicting phenotypic effects of pathogenic tubulin mutations. PLoS Comput Biol 2022; 18:e1010611. [PMID: 36206299 PMCID: PMC9581425 DOI: 10.1371/journal.pcbi.1010611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/19/2022] [Accepted: 09/28/2022] [Indexed: 11/21/2022] Open
Abstract
Cells rely heavily on microtubules for several processes, including cell division and molecular trafficking. Mutations in the different tubulin-α and -β proteins that comprise microtubules have been associated with various diseases and are often dominant, sporadic and congenital. While the earliest reported tubulin mutations affect neurodevelopment, mutations are also associated with other disorders such as bleeding disorders and infertility. We performed a systematic survey of tubulin mutations across all isotypes in order to improve our understanding of how they cause disease, and increase our ability to predict their phenotypic effects. Both protein structural analyses and computational variant effect predictors were very limited in their utility for differentiating between pathogenic and benign mutations. This was even worse for those genes associated with non-neurodevelopmental disorders. We selected tubulin-α and -β disease mutations that were most poorly predicted for experimental characterisation. These mutants co-localise to the mitotic spindle in HeLa cells, suggesting they may exert dominant-negative effects by altering microtubule properties. Our results show that tubulin mutations represent a blind spot for current computational approaches, being much more poorly predicted than mutations in most human disease genes. We suggest that this is likely due to their strong association with dominant-negative and gain-of-function mechanisms.
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Affiliation(s)
- Thomas J. Attard
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Julie P. I. Welburn
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Joseph A. Marsh
- MRC Human Genetics Unit, Institute of Genetics & Cancer, University of Edinburgh, Edinburgh, United Kingdom
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3
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Maillard C, Roux CJ, Charbit-Henrion F, Steffann J, Laquerriere A, Quazza F, Buisson NB. Tubulin mutations in human neurodevelopmental disorders. Semin Cell Dev Biol 2022; 137:87-95. [PMID: 35915025 DOI: 10.1016/j.semcdb.2022.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 10/16/2022]
Abstract
Mutations causing dysfunction of tubulins and microtubule-associated proteins, also known as tubulinopathies, are a group of recently described entities that lead to complex brain malformations. Anatomical and functional consequences of the disruption of tubulins include microcephaly, combined with abnormal corticogenesis due to impaired migration or lamination and abnormal growth cone dynamics of projecting and callosal axons. Key imaging features of tubulinopathies are characterized by three major patterns of malformations of cortical development (MCD): lissencephaly, microlissencephaly, and dysgyria. Additional distinctive MRI features include dysmorphism of the basal ganglia, midline commissural structure hypoplasia or agenesis, and cerebellar and brainstem hypoplasia. Tubulinopathies can be diagnosed as early as 21-24 gestational weeks using imaging and neuropathology, with possible extreme microlissencephaly with an extremely thin cortex, lissencephaly with either thick or thin/intermediate cortex, and dysgyria combined with cerebellar hypoplasia, pons hypoplasia and corpus callosum dysgenesis. More than 100 MCD-associated mutations have been reported in TUBA1A, TUBB2B, or TUBB3 genes, whereas fewer than ten are known in other genes such TUBB2A, TUBB or TUBG1. Although these mutations are scattered along the α- and β-tubulin sequences, recurrent mutations are consistently associated with almost identical cortical dysgenesis. Much of the evidence supports that these mutations alter the dynamic properties and functions of microtubules in several fashions. These include diminishing the abundance of functional tubulin heterodimers, altering GTP binding, altering longitudinal and lateral protofilament interactions, and impairing microtubule interactions with kinesin and/or dynein motors or with MAPs. In this review we discuss the recent advances in our understanding of the effects of mutations of tubulins and microtubule-associated proteins on human brain development and the pathogenesis of malformations of cortical development.
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Affiliation(s)
- Camille Maillard
- Université de Paris, Imagine Institute, Team Genetics and Development of the Cerebral Cortex, F-75015 Paris, France; Université de Paris, Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, F-75014 Paris, France
| | - Charles Joris Roux
- Pediatric Radiology, Necker Enfants Malades University Hospital, Université de Paris, Paris, France
| | - Fabienne Charbit-Henrion
- Université de Paris, Sorbonne Paris Cité, Imagine INSERM UMR1163, Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, France
| | - Julie Steffann
- Université de Paris, Sorbonne Paris Cité, Imagine INSERM UMR1163, Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, France
| | - Annie Laquerriere
- Pathology Laboratory, Rouen University Hospital, Rouen, France; NeoVasc Region-Inserm Team ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, University of Rouen, Rouen, France
| | - Floriane Quazza
- Pediatric Neurology, Necker Enfants Malades University Hospital, Université de Paris, Paris, France
| | - Nadia Bahi Buisson
- Université de Paris, Imagine Institute, Team Genetics and Development of the Cerebral Cortex, F-75015 Paris, France; Université de Paris, Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, F-75014 Paris, France; Pediatric Neurology, Necker Enfants Malades University Hospital, Université de Paris, Paris, France.
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4
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Çitli Ş, Serdaroglu E. Maternal Germline Mosaicism of a de Novo TUBB2B Mutation Leads to Complex Cortical Dysplasia in Two Siblings. Fetal Pediatr Pathol 2022; 41:155-165. [PMID: 32281916 DOI: 10.1080/15513815.2020.1753270] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Introduction: Complex cortical dysplasia with other brain malformations-7 (a.k.a. polymicrogyria) caused by mutations in TUBB2B gene is a clinically heterogeneous condition. Case report: We report two siblings with polymicrogyria. Brain MRI showed polymicrogyria, small brainstem, thin corpus callosum and fused basal ganglia. Karyotypes and chromosomal microarray analysis were normal. By whole exome sequencing, there were a de novo variant of c.728C > T (p.P243L) in both siblings and a common single nucleotide polymorphism (SNP) (c.718C > T) in both siblings and the mother. Seminal DNA analysis obtained from father was normal. Conclusion: Maternal germline mosaicism was considered because the sequencing result of the father's sperm was normal, two siblings had the same disease, and both patients and mother had the same SNP.
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Affiliation(s)
- Şenol Çitli
- Medical Genetics, Gaziosmanpasa University Medical Faculty, Tokat, Turkey
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Dekker J, Diderich KEM, Schot R, Husen SC, Dremmen MHG, Go ATJI, Weerts MJA, van Slegtenhorst MA, Mancini GMS. A novel family illustrating the mild phenotypic spectrum of TUBB2B variants. Eur J Paediatr Neurol 2021; 35:35-39. [PMID: 34592644 DOI: 10.1016/j.ejpn.2021.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/12/2021] [Accepted: 09/09/2021] [Indexed: 10/20/2022]
Abstract
TUBB2B codes for one of the isotypes of β-tubulin and dominant negative variants in this gene result in distinctive malformations of cortical development (MCD), including dysgyria, dysmorphic basal ganglia and cerebellar anomalies. We present a novel family with a heterozygous missense variant in TUBB2B and an unusually mild phenotype. First, at 21 37 weeks of gestation ultrasonography revealed a fetus with a relatively small head, enlarged lateral ventricles, borderline hypoplastic cerebellum and a thin corpus callosum. The couple opted for pregnancy termination. Exome sequencing on fetal material afterwards identified a heterozygous maternally inherited variant in TUBB2B (NM_178012.4 (TUBB2B):c.530A > T, p.(Asp177Val)), not present in GnomAD and predicted as damaging. The healthy mother had only a language delay in childhood. This inherited TUBB2B variant prompted re-evaluation of the older son of the couple, who presented with a mild delay in motor skills and speech. His MRI revealed mildly enlarged lateral ventricles, a thin corpus callosum, mild cortical dysgyria, and dysmorphic vermis and basal ganglia, a pattern typical of tubulinopathies. This son finally showed the same TUBB2B variant, supporting pathogenicity of the TUBB2B variant. These observations illustrate the wide phenotypic heterogeneity of tubulinopathies, including reduced penetrance and mild expressivity, that require careful evaluation in pre- and postnatal counseling.
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Affiliation(s)
- Jordy Dekker
- Department of Clinical Genetics, Erasmus MC University Medical Center, 3015, GD Rotterdam, the Netherlands
| | - Karin E M Diderich
- Department of Clinical Genetics, Erasmus MC University Medical Center, 3015, GD Rotterdam, the Netherlands
| | - Rachel Schot
- Department of Clinical Genetics, Erasmus MC University Medical Center, 3015, GD Rotterdam, the Netherlands
| | - Sofie C Husen
- Department of Obstetrics and Prenatal Medicine, Erasmus MC University Medical Center, 3015, GD Rotterdam, the Netherlands
| | - Marjolein H G Dremmen
- Department of Radiology and Nuclear Medicine, Erasmus MC University Medical Center, 3015, GD Rotterdam, the Netherlands
| | - Attie T J I Go
- Department of Obstetrics and Prenatal Medicine, Erasmus MC University Medical Center, 3015, GD Rotterdam, the Netherlands
| | - Marjolein J A Weerts
- Department of Clinical Genetics, Erasmus MC University Medical Center, 3015, GD Rotterdam, the Netherlands
| | - Marjon A van Slegtenhorst
- Department of Clinical Genetics, Erasmus MC University Medical Center, 3015, GD Rotterdam, the Netherlands
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus MC University Medical Center, 3015, GD Rotterdam, the Netherlands.
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6
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Cabet S, Karl K, Garel C, Delius M, Hartung J, Lesca G, Chaoui R, Guibaud L. Two different prenatal imaging cerebral patterns of tubulinopathy. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2021; 57:493-497. [PMID: 32149430 DOI: 10.1002/uog.22010] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/05/2020] [Accepted: 02/19/2020] [Indexed: 06/10/2023]
Abstract
To illustrate the prenatal cerebral imaging features associated with tubulinopathy, we report on five affected fetuses from unrelated families, with a de-novo heterozygous variant in a tubulin gene (TUBA1A, TUBB2B or TUBB3). We identified two distinct prenatal imaging patterns related to tubulinopathy: a severe form, characterized by enlarged germinal matrices, microlissencephaly and a kinked brainstem; and a mild form which has not been reported previously in the prenatal literature. The latter form is associated with non-specific features, including an asymmetric brainstem, corpus callosal dysgenesis, a lack of Sylvian fissure operculization and distortion of the anterior part of the interhemispheric fissure with subsequent impacted medial borders of the frontal lobes, the combination of which, in the absence of additional extracerebral anomalies, is highly suggestive of tubulinopathy. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.
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Affiliation(s)
- S Cabet
- Imagerie Pédiatrique et Fœtale, Hôpital Femme Mère Enfant, Université Claude Bernard Lyon 1, Lyon-Bron, France
- Service de Génétique, Groupement Hospitalier Est, Université Claude Bernard Lyon 1, Lyon-Bron, France
| | - K Karl
- Center for Prenatal Diagnosis Munich, Munich, Germany
- Department of Obstetrics and Gynecology, University Hospital, LMU Munich, Munich, Germany
| | - C Garel
- Department of Pediatric Imaging, Hôpital d'Enfants Armand-Trousseau APHP, Paris, France
| | - M Delius
- Department of Obstetrics and Gynecology, University Hospital, LMU Munich, Munich, Germany
| | - J Hartung
- Office of Prenatal Diagnosis, Berlin, Germany
| | - G Lesca
- Service de Génétique, Groupement Hospitalier Est, Université Claude Bernard Lyon 1, Lyon-Bron, France
| | - R Chaoui
- Center for Prenatal Diagnosis and Human Genetics, Berlin, Germany
| | - L Guibaud
- Imagerie Pédiatrique et Fœtale, Hôpital Femme Mère Enfant, Université Claude Bernard Lyon 1, Lyon-Bron, France
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7
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Fourel G, Boscheron C. Tubulin mutations in neurodevelopmental disorders as a tool to decipher microtubule function. FEBS Lett 2020; 594:3409-3438. [PMID: 33064843 DOI: 10.1002/1873-3468.13958] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 09/28/2020] [Accepted: 10/05/2020] [Indexed: 01/08/2023]
Abstract
Malformations of cortical development (MCDs) are a group of severe brain malformations associated with intellectual disability and refractory childhood epilepsy. Human missense heterozygous mutations in the 9 α-tubulin and 10 β-tubulin isoforms forming the heterodimers that assemble into microtubules (MTs) were found to cause MCDs. However, how a single mutated residue in a given tubulin isoform can perturb the entire microtubule population in a neuronal cell remains a crucial question. Here, we examined 85 MCD-associated tubulin mutations occurring in TUBA1A, TUBB2, and TUBB3 and their location in a three-dimensional (3D) microtubule cylinder. Mutations hitting residues exposed on the outer microtubule surface are likely to alter microtubule association with partners, while alteration of intradimer contacts may impair dimer stability and straightness. Other types of mutations are predicted to alter interdimer and lateral contacts, which are responsible for microtubule cohesion, rigidity, and dynamics. MCD-associated tubulin mutations surprisingly fall into all categories, thus providing unexpected insights into how a single mutation may impair microtubule function and elicit dominant effects in neurons.
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8
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International consensus recommendations on the diagnostic work-up for malformations of cortical development. Nat Rev Neurol 2020; 16:618-635. [PMID: 32895508 PMCID: PMC7790753 DOI: 10.1038/s41582-020-0395-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2020] [Indexed: 12/22/2022]
Abstract
Malformations of cortical development (MCDs) are neurodevelopmental disorders that result from abnormal development of the cerebral cortex in utero. MCDs place a substantial burden on affected individuals, their families and societies worldwide, as these individuals can experience lifelong drug-resistant epilepsy, cerebral palsy, feeding difficulties, intellectual disability and other neurological and behavioural anomalies. The diagnostic pathway for MCDs is complex owing to wide variations in presentation and aetiology, thereby hampering timely and adequate management. In this article, the international MCD network Neuro-MIG provides consensus recommendations to aid both expert and non-expert clinicians in the diagnostic work-up of MCDs with the aim of improving patient management worldwide. We reviewed the literature on clinical presentation, aetiology and diagnostic approaches for the main MCD subtypes and collected data on current practices and recommendations from clinicians and diagnostic laboratories within Neuro-MIG. We reached consensus by 42 professionals from 20 countries, using expert discussions and a Delphi consensus process. We present a diagnostic workflow that can be applied to any individual with MCD and a comprehensive list of MCD-related genes with their associated phenotypes. The workflow is designed to maximize the diagnostic yield and increase the number of patients receiving personalized care and counselling on prognosis and recurrence risk.
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Van Cauter S, Severino M, Ammendola R, Van Berkel B, Vavro H, van den Hauwe L, Rumboldt Z. Bilateral lesions of the basal ganglia and thalami (central grey matter)-pictorial review. Neuroradiology 2020; 62:1565-1605. [PMID: 32761278 PMCID: PMC7405775 DOI: 10.1007/s00234-020-02511-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/30/2020] [Indexed: 12/11/2022]
Abstract
The basal ganglia and thalami are paired deep grey matter structures with extensive metabolic activity that renders them susceptible to injury by various diseases. Most pathological processes lead to bilateral lesions, which may be symmetric or asymmetric, frequently showing characteristic patterns on imaging studies. In this comprehensive pictorial review, the most common and/or typical genetic, acquired metabolic/toxic, infectious, inflammatory, vascular and neoplastic pathologies affecting the central grey matter are subdivided according to the preferential location of the lesions: in the basal ganglia, in the thalami or both. The characteristic imaging findings are described with emphasis on the differential diagnosis and clinical context.
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Affiliation(s)
- Sofie Van Cauter
- Department of Medical Imaging, Ziekenhuis Oost-Limburg, Schiepse Bos 6, 3600, Genk, Belgium. .,Department of Radiology, University Hospitals Leuven, Herestraat 39, 3000, Leuven, Belgium.
| | - Mariasavina Severino
- Neuroradiology Unit, IRCCS Instituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Rosamaria Ammendola
- Neuroradiology Unit, IRCCS Instituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Brecht Van Berkel
- Department of Medical Imaging, Ziekenhuis Oost-Limburg, Schiepse Bos 6, 3600, Genk, Belgium.,Department of Radiology, University Hospitals Leuven, Herestraat 39, 3000, Leuven, Belgium
| | - Hrvoje Vavro
- Department of Diagnostic and Interventional Radiology, University Hospital Dubrava, Avenija Gojka Šuška 6, Zagreb, Croatia
| | - Luc van den Hauwe
- Department of Radiology, University Hospital Antwerp, Wilrijkstraat 10, 2650, Edegem, Belgium.,Department of Medical Imaging, AZ KLINA, Augustijnslei 100, 2930, Brasschaat, Belgium
| | - Zoran Rumboldt
- Department of Radiology, University of Rijeka School of Medicine, Ulica Braće Branchetta 20, 51000, Rijeka, Croatia.,Department of Radiology, Medical University of South Carolina, 96 Jonathan Lucas Street, Charleston, SC, 29425, USA
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Bittermann E, Abdelhamed Z, Liegel RP, Menke C, Timms A, Beier DR, Stottmann RW. Differential requirements of tubulin genes in mammalian forebrain development. PLoS Genet 2019; 15:e1008243. [PMID: 31386652 PMCID: PMC6697361 DOI: 10.1371/journal.pgen.1008243] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 08/16/2019] [Accepted: 06/12/2019] [Indexed: 11/24/2022] Open
Abstract
Tubulin genes encode a series of homologous proteins used to construct microtubules which are essential for multiple cellular processes. Neural development is particularly reliant on functional microtubule structures. Tubulin genes comprise a large family of genes with very high sequence similarity between multiple family members. Human genetics has demonstrated that a large spectrum of cortical malformations are associated with de novo heterozygous mutations in tubulin genes. However, the absolute requirement for many of these genes in development and disease has not been previously tested in genetic loss of function models. Here we directly test the requirement for Tuba1a, Tubb2a and Tubb2b in the mouse by deleting each gene individually using CRISPR-Cas9 genome editing. We show that loss of Tubb2a or Tubb2b does not impair survival but does lead to relatively mild cortical malformation phenotypes. In contrast, loss of Tuba1a is perinatal lethal and leads to significant forebrain dysmorphology. We also present a novel mouse ENU allele of Tuba1a with phenotypes similar to the null allele. This demonstrates the requirements for each of the tubulin genes and levels of functional redundancy are quite different throughout the gene family. The ability of the mouse to survive in the absence of some tubulin genes known to cause disease in humans suggests future intervention strategies for these devastating tubulinopathy diseases.
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Affiliation(s)
- Elizabeth Bittermann
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Zakia Abdelhamed
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Anatomy and Embryology, Faculty of Medicine (Girl’s Section), Al-Azhar University, Cairo, Egypt
| | - Ryan P. Liegel
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Chelsea Menke
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Andrew Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - David R. Beier
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington Medical School, Seattle, Washington, United States of America
| | - Rolf W. Stottmann
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
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11
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Epilepsy in Tubulinopathy: Personal Series and Literature Review. Cells 2019; 8:cells8070669. [PMID: 31269740 PMCID: PMC6678821 DOI: 10.3390/cells8070669] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 11/17/2022] Open
Abstract
Mutations in tubulin genes are responsible for a large spectrum of brain malformations secondary to abnormal neuronal migration, organization, differentiation and axon guidance and maintenance. Motor impairment, intellectual disability and epilepsy are the main clinical symptoms. In the present study 15 patients from a personal cohort and 75 from 21 published studies carrying mutations in TUBA1A, TUBB2B and TUBB3 tubulin genes were evaluated with the aim to define a clinical and electrophysiological associated pattern. Epilepsy shows a wide range of severity without a specific pattern. Mutations in TUBA1A (60%) and TUBB2B (74%) and TUBB3 (25%) genes are associated with epilepsy. The accurate analysis of the Electroencephalogram (EEG) pattern in wakefulness and sleep in our series allows us to detect significant abnormalities of the background activity in 100% of patients. The involvement of white matter and of the inter-hemispheric connection structures typically observed in tubulinopathies is evidenced by the high percentage of asynchronisms in the organization of sleep activity recorded. In addition to asymmetries of the background activity, excess of slowing, low amplitude and Magnetic Resonance (MR) imaging confirm the presence of extensive brain malformations involving subcortical and midline structures. In conclusion, epilepsy in tubulinopathies when present has a favorable evolution over time suggesting a not particularly aggressive therapeutic approach.
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12
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Hebebrand M, Hüffmeier U, Trollmann R, Hehr U, Uebe S, Ekici AB, Kraus C, Krumbiegel M, Reis A, Thiel CT, Popp B. The mutational and phenotypic spectrum of TUBA1A-associated tubulinopathy. Orphanet J Rare Dis 2019; 14:38. [PMID: 30744660 PMCID: PMC6371496 DOI: 10.1186/s13023-019-1020-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 02/03/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The TUBA1A-associated tubulinopathy is clinically heterogeneous with brain malformations, microcephaly, developmental delay and epilepsy being the main clinical features. It is an autosomal dominant disorder mostly caused by de novo variants in TUBA1A. RESULTS In three individuals with developmental delay we identified heterozygous de novo missense variants in TUBA1A using exome sequencing. While the c.1307G > A, p.(Gly436Asp) variant was novel, the two variants c.518C > T, p.(Pro173Leu) and c.641G > A, p.(Arg214His) were previously described. We compared the variable phenotype observed in these individuals with a carefully conducted review of the current literature and identified 166 individuals, 146 born and 20 fetuses with a TUBA1A variant. In 107 cases with available clinical information we standardized the reported phenotypes according to the Human Phenotype Ontology. The most commonly reported features were developmental delay (98%), anomalies of the corpus callosum (96%), microcephaly (76%) and lissencephaly (agyria-pachygyria) (70%), although reporting was incomplete in the different studies. We identified a total of 121 specific variants, including 15 recurrent ones. Missense variants cluster in the C-terminal region around the most commonly affected amino acid position Arg402 (13.3%). In a three-dimensional protein model, 38.6% of all disease-causing variants including those in the C-terminal region are predicted to affect the binding of microtubule-associated proteins or motor proteins. Genotype-phenotype analysis for recurrent variants showed an overrepresentation of certain clinical features. However, individuals with these variants are often reported in the same publication. CONCLUSIONS With 166 individuals, we present the most comprehensive phenotypic and genotypic standardized synopsis for clinical interpretation of TUBA1A variants. Despite this considerable number, a detailed genotype-phenotype characterization is limited by large inter-study variability in reporting.
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Affiliation(s)
- Moritz Hebebrand
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Ulrike Hüffmeier
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Regina Trollmann
- Department of Pediatrics, Division of Neuropediatrics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ute Hehr
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Steffen Uebe
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Arif B Ekici
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Cornelia Kraus
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Mandy Krumbiegel
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - André Reis
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Christian T Thiel
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany.
| | - Bernt Popp
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
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13
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Tubulin genes and malformations of cortical development. Eur J Med Genet 2018; 61:744-754. [PMID: 30016746 DOI: 10.1016/j.ejmg.2018.07.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 06/03/2018] [Accepted: 07/12/2018] [Indexed: 01/18/2023]
Abstract
A large number of genes encoding for tubulin proteins are expressed in the developing brain. Each is subject to specific spatial and temporal expression patterns. However, most are highly expressed in post-mitotic neurons during stages of neuronal migration and differentiation. The major tubulin subclasses (alpha- and beta-tubulin) share high sequence and structural homology. These globular proteins form heterodimers and subsequently co-assemble into microtubules. Microtubules are dynamic, cytoskeletal polymers which play key roles in cellular processes crucial for cortical development, including neuronal proliferation, migration and cortical laminar organisation. Mutations in seven genes encoding alpha-tubulin (TUBA1A), beta-tubulin (TUBB2A, TUBB2B, TUBB3, TUBB4A, TUBB) and gamma-tubulin (TUBG1) isoforms have been associated with a wide and overlapping range of brain malformations or "Tubulinopathies". The majority of cortical phenotypes include lissencephaly, polymicrogyria, microlissencephaly and simplified gyration. Well-known hallmarks of the tubulinopathies include dysmorphism of the basal ganglia (fusion of the caudate nucleus and putamen with absence of the anterior limb of the internal capsule), midline commissural structures hypoplasia and/or agenesis (anterior commissure, corpus callosum and fornix), hypoplasia of the oculomotor and optic nerves, cerebellar hypoplasia or dysplasia and dysmorphism of the hind-brain structures. The cortical and extra-cortical brain phenotypes observed are largely dependent on the specific tubulin gene affected. In the present review, all the published data on tubulin family gene mutations and the associated cortical phenotypes are summarized. In addition, the most typical neuroimaging patterns of malformations of cortical development associated with tubulin gene mutations detected on the basis of our own experience are described.
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14
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Tubulinopathies continued: refining the phenotypic spectrum associated with variants in TUBG1. Eur J Hum Genet 2018; 26:1132-1142. [PMID: 29706637 PMCID: PMC6057922 DOI: 10.1038/s41431-018-0146-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 03/02/2018] [Accepted: 03/13/2018] [Indexed: 12/30/2022] Open
Abstract
Tubulinopathies are a heterogeneous group of conditions with a wide spectrum of clinical severity resulting from variants in genes of the tubulin superfamily. Variants in TUBG1 have been described in three patients with posterior predominant pachygyria and microcephaly. We here report eight additional patients with four novel heterozygous variants in TUBG1 identified by next-generation sequencing (NGS) analysis. All had severe motor and cognitive impairment and all except one developed seizures in early life. The core imaging features included a pachygyric cortex with posterior to anterior gradient, enlarged lateral ventricles most pronounced over the posterior horns, and variable degrees of reduced white matter volume. Basal ganglia, corpus callosum, brainstem, and cerebellum were often normal, in contrast to patients with variants in other tubulin genes where these structures are frequently malformed. The imaging phenotype associated with variants in TUBG1 is therefore more in line with the phenotype resulting from variants in LIS1 (a.k.a. PAFAH1B1). This difference may, at least in part, be explained by gamma-tubulin’s physiological function in microtubule nucleation, which differs from that of alpha and beta-tubulin.
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15
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Minoura I. Towards an understanding of the isotype-specific functions of tubulin in neurons: Technical advances in tubulin expression and purification. Neurosci Res 2017; 122:1-8. [PMID: 28412269 DOI: 10.1016/j.neures.2017.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/29/2017] [Accepted: 04/07/2017] [Indexed: 12/20/2022]
Abstract
Microtubules are cytoskeletal filaments critical for determining the complex morphology of neurons, as well as the basic architecture and organization of mitosis in all eukaryotic cells. Microtubules in humans are composed of 8 α- and 9 β-tubulin isotypes, each of which is encoded by different members of a multi-gene family. The expression pattern of tubulin isotypes, in addition to isotype-specific post-translational modifications, is thought to be critical for the morphogenesis of axons and dendrites. Recent studies revealed that several neurodevelopmental disorders are caused by mutations of specific tubulin isotypes, suggesting that each tubulin isotype has distinct functions. Therefore, in vitro and in vivo functional analyses of tubulin isotypes are important to understand the pathogenesis of developmental disorders. Likewise, analysis of developmental disorders may clarify the function of different tubulin isotypes. In this respect, both the preparation of specific tubulin isotypes and of specific mutant tubulin proteins is critical to understanding the function of tubulin. In the last 20 years, various methods have been developed to study functional differences between tubulin isotypes and the functional defects caused by tubulin mutations. These technical achievements have been discussed in this review. The function of tubulin/microtubules in neuronal morphogenesis as revealed through these techniques has also been described.
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Affiliation(s)
- Itsushi Minoura
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Goryo Chemical Inc., Earee Bldg. 5F, Kita 8 Nishi 18-35-100, Chuo-ku, Sapporo 060-0008, Japan.
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16
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Tanyalcin I, Stouffs K, Daneels D, Al Assaf C, Lissens W, Jansen A, Gheldof A. Convert your favorite protein modeling program into a mutation predictor: "MODICT". BMC Bioinformatics 2016; 17:425. [PMID: 27760515 PMCID: PMC5070100 DOI: 10.1186/s12859-016-1286-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 09/28/2016] [Indexed: 01/09/2023] Open
Abstract
Background Predict whether a mutation is deleterious based on the custom 3D model of a protein. Results We have developed modict, a mutation prediction tool which is based on per residue rmsd (root mean square deviation) values of superimposed 3D protein models. Our mathematical algorithm was tested for 42 described mutations in multiple genes including renin (REN), beta-tubulin (TUBB2B), biotinidase (BTD), sphingomyelin phosphodiesterase-1 (SMPD1), phenylalanine hydroxylase (PAH) and medium chain Acyl-Coa dehydrogenase (ACADM). Moreover, modict scores corresponded to experimentally verified residual enzyme activities in mutated biotinidase, phenylalanine hydroxylase and medium chain Acyl-CoA dehydrogenase. Several commercially available prediction algorithms were tested and results were compared. The modictperl package and the manual can be downloaded from https://github.com/IbrahimTanyalcin/MODICT. Conclusions We show here that modict is capable tool for mutation effect prediction at the protein level, using superimposed 3D protein models instead of sequence based algorithms used by polyphen and sift. Electronic supplementary material The online version of this article (doi:10.1186/s12859-016-1286-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ibrahim Tanyalcin
- Center for Medical Genetics, UZ Brussel, Laarbeeklaan 101, Brussel, 1090, Belgium. .,Neurogenetics Research Group, Reproduction Genetics and Regenerative Medicine Research Group, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, Brussel, 1090, Belgium.
| | - Katrien Stouffs
- Center for Medical Genetics, Reproduction and Genetics, Reproduction Genetics and Regenerative Medicine, Vrije Universiteit Brussel (VUB), UZ Brussel, Laarbeeklaan 101, Brussel, 1090, Belgium
| | - Dorien Daneels
- Center for Medical Genetics, Reproduction and Genetics, Reproduction Genetics and Regenerative Medicine, Vrije Universiteit Brussel (VUB), UZ Brussel, Laarbeeklaan 101, Brussel, 1090, Belgium
| | - Carla Al Assaf
- Center for Human Genetics, KU Leuven and University Hospitals Leuven, Herestraat 49, Leuven, 3000, Belgium
| | - Willy Lissens
- Center for Medical Genetics, Reproduction and Genetics, Reproduction Genetics and Regenerative Medicine, Vrije Universiteit Brussel (VUB), UZ Brussel, Laarbeeklaan 101, Brussel, 1090, Belgium
| | - Anna Jansen
- Center for Medical Genetics, UZ Brussel, Laarbeeklaan 101, Brussel, 1090, Belgium.,Neurogenetics Research Group, Reproduction Genetics and Regenerative Medicine Research Group, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, Brussel, 1090, Belgium.,Pediatric Neurology Unit, Department of Pediatrics, UZ Brussel, Laarbeeklaan 101, Brussel, 1090, Belgium
| | - Alexander Gheldof
- Center for Medical Genetics, Reproduction and Genetics, Reproduction Genetics and Regenerative Medicine, Vrije Universiteit Brussel (VUB), UZ Brussel, Laarbeeklaan 101, Brussel, 1090, Belgium
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17
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Kobeissy FH, Hansen K, Neumann M, Fu S, Jin K, Liu J. Deciphering the Role of Emx1 in Neurogenesis: A Neuroproteomics Approach. Front Mol Neurosci 2016; 9:98. [PMID: 27799894 PMCID: PMC5065984 DOI: 10.3389/fnmol.2016.00098] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/26/2016] [Indexed: 12/18/2022] Open
Abstract
Emx1 has long been implicated in embryonic brain development. Previously we found that mice null of Emx1 gene had smaller dentate gyri and reduced neurogenesis, although the molecular mechanisms underlying this defect was not well understood. To decipher the role of Emx1 gene in neural regeneration and the timing of its involvement, we determine the frequency of neural stem cells (NSCs) in embryonic and adult forebrains of Emx1 wild type (WT) and knock out (KO) mice in the neurosphere assay. Emx1 gene deletion reduced the frequency and self-renewal capacity of NSCs of the embryonic brain but did not affect neuronal or glial differentiation. Emx1 KO NSCs also exhibited a reduced migratory capacity in response to serum or vascular endothelial growth factor (VEGF) in the Boyden chamber migration assay compared to their WT counterparts. A thorough comparison between NSC lysates from Emx1 WT and KO mice utilizing 2D-PAGE coupled with tandem mass spectrometry revealed 38 proteins differentially expressed between genotypes, including the F-actin depolymerization factor Cofilin. A global systems biology and cluster analysis identified several potential mechanisms and cellular pathways implicated in altered neurogenesis, all involving Cofilin1. Protein interaction network maps with functional enrichment analysis further indicated that the differentially expressed proteins participated in neural-specific functions including brain development, axonal guidance, synaptic transmission, neurogenesis, and hippocampal morphology, with VEGF as the upstream regulator intertwined with Cofilin1 and Emx1. Functional validation analysis indicated that apart from the overall reduced level of phosphorylated Cofilin1 (p-Cofilin1) in the Emx1 KO NSCs compared to WT NSCs as demonstrated in the western blot analysis, VEGF was able to induce more Cofilin1 phosphorylation and FLK expression only in the latter. Our results suggest that a defect in Cofilin1 phosphorylation induced by VEGF or other growth factors might contribute to the reduced neurogenesis in the Emx1 null mice during brain development.
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Affiliation(s)
- Firas H Kobeissy
- Department of Psychiatry, Center for Neuroproteomics and Biomarkers Research, University of Florida Gainesville, FL, USA
| | - Katharina Hansen
- Department of Neurological Surgery, University of California, San FranciscoSan Francisco, CA, USA; San Francisco VA Medical CenterSan Francisco, CA, USA
| | - Melanie Neumann
- Department of Neurological Surgery, University of California, San FranciscoSan Francisco, CA, USA; San Francisco VA Medical CenterSan Francisco, CA, USA
| | - Shuping Fu
- Department of Neurological Surgery, University of California, San FranciscoSan Francisco, CA, USA; San Francisco VA Medical CenterSan Francisco, CA, USA; Key Laboratory of Acupuncture and Medicine Research of Minister of Education, Nanjing University of Chinese MedicineNanjing, China
| | - Kulin Jin
- Pharmacology & Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Jialing Liu
- Department of Neurological Surgery, University of California, San FranciscoSan Francisco, CA, USA; San Francisco VA Medical CenterSan Francisco, CA, USA
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18
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Stottmann RW, Driver A, Gutierrez A, Skelton MR, Muntifering M, Stepien C, Knudson L, Kofron M, Vorhees CV, Williams MT. A heterozygous mutation in tubulin, beta 2B ( Tubb2b ) causes cognitive deficits and hippocampal disorganization. GENES BRAIN AND BEHAVIOR 2016; 16:250-259. [PMID: 27594048 DOI: 10.1111/gbb.12327] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/29/2016] [Accepted: 08/30/2016] [Indexed: 01/05/2023]
Abstract
Development of the mammalian forebrain requires a significant contribution from tubulin proteins to physically facilitate both the large number of mitoses in the neurogenic brain (in the form of mitotic spindles) as well as support cellular scaffolds to guide radial migration (radial glial neuroblasts). Recent studies have identified a number of mutations in human tubulin genes affecting the forebrain, including TUBB2B . We previously identified a mouse mutation in Tubb2b and we show here that mice heterozygous for this missense mutation in Tubb2b have significant cognitive defects in spatial learning and memory. We further showed reduced hippocampal long-term potentiation consistent with these defects. In addition to the behavioural and physiological deficits, we show here abnormal hippocampal morphology. Taken together, these phenotypes suggest that heterozygous mutations in tubulin genes result in cognitive deficits not previously appreciated. This has implications for design and interpretation of genetic testing for humans with intellectual disability disorders.
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Affiliation(s)
- Rolf W Stottmann
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.,Graduate Program in Neuroscience, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Ashley Driver
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Arnold Gutierrez
- Graduate Program in Neuroscience, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.,Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Matthew R Skelton
- Graduate Program in Neuroscience, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.,Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Michael Muntifering
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Christopher Stepien
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Luke Knudson
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Matthew Kofron
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Charles V Vorhees
- Graduate Program in Neuroscience, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.,Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Michael T Williams
- Graduate Program in Neuroscience, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.,Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
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19
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Chakraborti S, Natarajan K, Curiel J, Janke C, Liu J. The emerging role of the tubulin code: From the tubulin molecule to neuronal function and disease. Cytoskeleton (Hoboken) 2016; 73:521-550. [PMID: 26934450 DOI: 10.1002/cm.21290] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/18/2016] [Accepted: 02/26/2016] [Indexed: 11/11/2022]
Abstract
Across different cell types and tissues, microtubules are assembled from highly conserved dimers of α- and β-tubulin. Despite their highly similar structures, microtubules have functional heterogeneity, generated either by the expression of different tubulin genes, encoding distinct isotypes, or by posttranslational modifications of tubulin. This genetically encoded and posttranslational generated heterogeneity of tubulin-the "tubulin code"-has the potential to modulate microtubule structure, dynamics, and interactions with associated proteins. The tubulin code is therefore believed to regulate microtubule functions on a cellular and sub-cellular level. This review highlights the importance of the tubulin code for tubulin structure, as well as on microtubule dynamics and functions in neurons. It further summarizes recent developments in the understanding of mutations in tubulin genes, and how they are linked to neurodegenerative and neurodevelopmental disorders. The current advances in the knowledge of the tubulin code on the molecular and the functional level will certainly lead to a better understanding of how complex signaling events control microtubule functions, especially in cells of the nervous system. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Soumyananda Chakraborti
- Institut Curie, PSL Research University, CNRS, INSERM, UMR 3348, Orsay, F-91405, France.,Université Paris Sud, Université Paris-Saclay, CNRS, UMR 3348, Orsay, F-91405, France
| | - Kathiresan Natarajan
- Institut Curie, PSL Research University, CNRS, INSERM, UMR 3348, Orsay, F-91405, France.,Université Paris Sud, Université Paris-Saclay, CNRS, UMR 3348, Orsay, F-91405, France
| | - Julian Curiel
- Children's National Health System, Center for Neuroscience Research, Washington, District of Columbia
| | - Carsten Janke
- Institut Curie, PSL Research University, CNRS, INSERM, UMR 3348, Orsay, F-91405, France. .,Université Paris Sud, Université Paris-Saclay, CNRS, UMR 3348, Orsay, F-91405, France.
| | - Judy Liu
- Children's National Health System, Center for Neuroscience Research, Washington, District of Columbia.
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20
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Jansen AC, Robitaille Y, Honavar M, Mullatti N, Leventer RJ, Andermann E, Andermann F, Squier W. The histopathology of polymicrogyria: a series of 71 brain autopsy studies. Dev Med Child Neurol 2016; 58:39-48. [PMID: 26179148 DOI: 10.1111/dmcn.12840] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/09/2015] [Indexed: 11/30/2022]
Abstract
AIM Polymicrogyria (PMG) is one of the most common forms of cortical malformation yet the mechanism of its development remains unknown. This study describes the histopathological aspects of PMG in a large series including a significant proportion of fetal cases. METHOD We have reviewed the neuropathology and medical records of 44 fetuses and 27 children and adults in whom the cortical architecture was focally or diffusely replaced by one or more festooning bands of neurons. RESULTS The pial surface of the brain overlying the polymicrogyric cortex was abnormal in almost 90% of cases irrespective of the aetiology. This accords with animal studies indicating the importance of the leptomeninges in cortical development. The aetiology of PMG was highly heterogeneous and there was no correlation between cortical layering patterns and aetiology. PMG was almost always associated with other brain malformations. INTERPRETATION The inclusion of many fetal cases has allowed us to examine the early developmental stages of PMG. The study indicates the significance of surface signals responsible for human corticogenesis and the complex interaction between genetic and environmental factors leading to this common endpoint of cortical maldevelopment.
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Affiliation(s)
- Anna C Jansen
- Pediatric Neurology Unit, Department of Pediatrics, UZ Brussel, Brussels, Belgium.,Department of Public Health, Vrije Universiteit Brussel, Brussels, Belgium
| | - Yves Robitaille
- Department of Pathology, Centre Hospitalier Universitaire Sainte-Justine, Université de Montreal, Montreal, QC, Canada
| | - Mrinalini Honavar
- Department of Clinical Neuropathology, King's College Hospital, Denmark Hill, London, UK.,Service of Anatomic Pathology, Hospital Pedro Hispano, Matosinhos, Portugal
| | - Nandini Mullatti
- Department of Clinical Neurophysiology, King's College Hospital, Denmark Hill, London, UK
| | - Richard J Leventer
- Department of Neurology, University Department of Pediatrics, Murdoch Children's Research Institute, Royal Children's Hospital, The University of Melbourne, Parkville, Vic., Australia
| | - Eva Andermann
- Neurogenetics Unit, Montreal Neurological Hospital and Institute, and Departments of Neurology & Neurosurgery and Human Genetics, McGill University, Montreal, QC, Canada
| | - Frederick Andermann
- Seizure Clinic, Montreal Neurological Hospital and Institute, and Departments of Neurology & Neurosurgery and Paediatrics, McGill University, Montreal, QC, Canada
| | - Waney Squier
- Department of Neuropathology, Oxford University John Radcliffe Hospital, Oxford, UK
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21
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Bahi-Buisson N, Poirier K, Fourniol F, Saillour Y, Valence S, Lebrun N, Hully M, Bianco CF, Boddaert N, Elie C, Lascelles K, Souville I, Beldjord C, Chelly J. The wide spectrum of tubulinopathies: what are the key features for the diagnosis? ACTA ACUST UNITED AC 2014; 137:1676-700. [PMID: 24860126 DOI: 10.1093/brain/awu082] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Complex cortical malformations associated with mutations in tubulin genes: TUBA1A, TUBA8, TUBB2B, TUBB3, TUBB5 and TUBG1 commonly referred to as tubulinopathies, are a heterogeneous group of conditions with a wide spectrum of clinical severity. Among the 106 patients selected as having complex cortical malformations, 45 were found to carry mutations in TUBA1A (42.5%), 18 in TUBB2B (16.9%), 11 in TUBB3 (10.4%), three in TUBB5 (2.8%), and three in TUBG1 (2.8%). No mutations were identified in TUBA8. Systematic review of patients' neuroimaging and neuropathological data allowed us to distinguish at least five cortical malformation syndromes: (i) microlissencephaly (n = 12); (ii) lissencephaly (n = 19); (iii) central pachygyria and polymicrogyria-like cortical dysplasia (n = 24); (iv) generalized polymicrogyria-like cortical dysplasia (n = 6); and (v) a 'simplified' gyral pattern with area of focal polymicrogyria (n = 19). Dysmorphic basal ganglia are the hallmark of tubulinopathies (found in 75% of cases) and are present in 100% of central pachygyria and polymicrogyria-like cortical dysplasia and simplified gyral malformation syndromes. Tubulinopathies are also characterized by a high prevalence of corpus callosum agenesis (32/80; 40%), and mild to severe cerebellar hypoplasia and dysplasia (63/80; 78.7%). Foetal cases (n = 25) represent the severe end of the spectrum and show specific abnormalities that provide insights into the underlying pathophysiology. The overall complexity of tubulinopathies reflects the pleiotropic effects of tubulins and their specific spatio-temporal profiles of expression. In line with previous reports, this large cohort further clarifies overlapping phenotypes between tubulinopathies and although current structural data do not allow prediction of mutation-related phenotypes, within each mutated gene there is an associated predominant pattern of cortical dysgenesis allowing some phenotype-genotype correlation. The core phenotype of TUBA1A and TUBG1 tubulinopathies are lissencephalies and microlissencephalies, whereas TUBB2B tubulinopathies show in the majority, centrally predominant polymicrogyria-like cortical dysplasia. By contrast, TUBB3 and TUBB5 mutations cause milder malformations with focal or multifocal polymicrogyria-like cortical dysplasia with abnormal and simplified gyral pattern.
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Affiliation(s)
- Nadia Bahi-Buisson
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France3 Université Paris Descartes, Sorbonne Paris Cité, Institut Imagine, Paris, France4 INSERM UMR-1163, Embryology and genetics of congenital malformations, Paris, France5 Service de Neurologie pédiatrique, Assistance Publique-Hôpitaux de Paris (AP-HP), hôpital Necker, Paris, France
| | - Karine Poirier
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
| | | | - Yoann Saillour
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
| | - Stéphanie Valence
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
| | - Nicolas Lebrun
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
| | - Marie Hully
- 5 Service de Neurologie pédiatrique, Assistance Publique-Hôpitaux de Paris (AP-HP), hôpital Necker, Paris, France
| | | | - Nathalie Boddaert
- 8 Service de Radiologie Pédiatrique, AP-HP, hôpital Necker, Paris, France9 Inserm, U797-INSERM-CEA, Service Hospitalier Frédéric Joliot, CEA, 4, place du General Leclerc, 91406, Orsay, France
| | - Caroline Elie
- 10 BioInformatic Department-AP-HP, hôpital Necker-Enfants Malades, Paris, France
| | | | - Isabelle Souville
- 12 Service de Biologie Moleculaire et Genetique, Pavillon Cassini AP-HP, Hôpital Cochin, Paris, France
| | | | - Cherif Beldjord
- 12 Service de Biologie Moleculaire et Genetique, Pavillon Cassini AP-HP, Hôpital Cochin, Paris, France
| | - Jamel Chelly
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
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22
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Fallet-Bianco C, Laquerrière A, Poirier K, Razavi F, Guimiot F, Dias P, Loeuillet L, Lascelles K, Beldjord C, Carion N, Toussaint A, Revencu N, Addor MC, Lhermitte B, Gonzales M, Martinovich J, Bessieres B, Marcy-Bonnière M, Jossic F, Marcorelles P, Loget P, Chelly J, Bahi-Buisson N. Mutations in tubulin genes are frequent causes of various foetal malformations of cortical development including microlissencephaly. Acta Neuropathol Commun 2014; 2:69. [PMID: 25059107 PMCID: PMC4222268 DOI: 10.1186/2051-5960-2-69] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 06/04/2014] [Indexed: 01/18/2023] Open
Abstract
Complex cortical malformations associated with mutations in tubulin genes are commonly referred to as “Tubulinopathies”. To further characterize the mutation frequency and phenotypes associated with tubulin mutations, we studied a cohort of 60 foetal cases. Twenty-six tubulin mutations were identified, of which TUBA1A mutations were the most prevalent (19 cases), followed by TUBB2B (6 cases) and TUBB3 (one case). Three subtypes clearly emerged. The most frequent (n = 13) was microlissencephaly with corpus callosum agenesis, severely hypoplastic brainstem and cerebellum. The cortical plate was either absent (6/13), with a 2–3 layered pattern (5/13) or less frequently thickened (2/13), often associated with neuroglial overmigration (4/13). All cases had voluminous germinal zones and ganglionic eminences. The second subtype was lissencephaly (n = 7), either classical (4/7) or associated with cerebellar hypoplasia (3/7) with corpus callosum agenesis (6/7). All foetuses with lissencephaly and cerebellar hypoplasia carried distinct TUBA1A mutations, while those with classical lissencephaly harbored recurrent mutations in TUBA1A (3 cases) or TUBB2B (1 case). The third group was polymicrogyria-like cortical dysplasia (n = 6), consisting of asymmetric multifocal or generalized polymicrogyria with inconstant corpus callosum agenesis (4/6) and hypoplastic brainstem and cerebellum (3/6). Polymicrogyria was either unlayered or 4-layered with neuronal heterotopias (5/6) and occasional focal neuroglial overmigration (2/6). Three had TUBA1A mutations and 3 TUBB2B mutations. Foetal TUBA1A tubulinopathies most often consist in microlissencephaly or classical lissencephaly with corpus callosum agenesis, but polymicrogyria may also occur. Conversely, TUBB2B mutations are responsible for either polymicrogyria (4/6) or microlissencephaly (2/6).
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Stutterd CA, Leventer RJ. Polymicrogyria: a common and heterogeneous malformation of cortical development. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2014; 166C:227-39. [PMID: 24888723 DOI: 10.1002/ajmg.c.31399] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Polymicrogyria (PMG) is one of the most common malformations of cortical development. It is characterized by overfolding of the cerebral cortex and abnormal cortical layering. It is a highly heterogeneous malformation with variable clinical and imaging features, pathological findings, and etiologies. It may occur as an isolated cortical malformation, or in association with other malformations within the brain or body as part of a multiple congenital anomaly syndrome. Polymicrogyria shows variable topographic patterns with the bilateral perisylvian pattern being most common. Schizencephaly is a subtype of PMG in which the overfolded cortex lines full-thickness clefts connecting the subarachnoid space with the cerebral ventricles. Both genetic and non-genetic causes of PMG have been identified. Non-genetic causes include congenital cytomegalovirus infection and in utero ischemia. Genetic causes include metabolic conditions such as peroxisomal disorders and the 22q11.2 and 1p36 continguous gene deletion syndromes. Mutations in over 30 genes have been found in association with PMG, especially mutations in the tubulin family of genes. Mutations in the (PI3K)-AKT pathway have been found in association PMG and megalencephaly. Despite recent genetic advances, the mechanisms by which polymicrogyric cortex forms and causes of the majority of cases remain unknown, making diagnostic and prenatal testing and genetic counseling challenging. This review summarizes the clinical, imaging, pathologic, and etiologic features of PMG, highlighting recent genetic advances.
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Cushion TD, Paciorkowski AR, Pilz DT, Mullins JGL, Seltzer LE, Marion RW, Tuttle E, Ghoneim D, Christian SL, Chung SK, Rees MI, Dobyns WB. De novo mutations in the beta-tubulin gene TUBB2A cause simplified gyral patterning and infantile-onset epilepsy. Am J Hum Genet 2014; 94:634-41. [PMID: 24702957 DOI: 10.1016/j.ajhg.2014.03.009] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 03/14/2014] [Indexed: 12/22/2022] Open
Abstract
Tubulins, and microtubule polymers into which they incorporate, play critical mechanical roles in neuronal function during cell proliferation, neuronal migration, and postmigrational development: the three major overlapping events of mammalian cerebral cortex development. A number of neuronally expressed tubulin genes are associated with a spectrum of disorders affecting cerebral cortex formation. Such "tubulinopathies" include lissencephaly/pachygyria, polymicrogyria-like malformations, and simplified gyral patterns, in addition to characteristic extracortical features, such as corpus callosal, basal ganglia, and cerebellar abnormalities. Epilepsy is a common finding in these related disorders. Here we describe two unrelated individuals with infantile-onset epilepsy and abnormalities of brain morphology, harboring de novo variants that affect adjacent amino acids in a beta-tubulin gene TUBB2A. Located in a highly conserved loop, we demonstrate impaired tubulin and microtubule function resulting from each variant in vitro and by using in silico predictive modeling. We propose that the affected functional loop directly associates with the alpha-tubulin-bound guanosine triphosphate (GTP) molecule, impairing the intradimer interface and correct formation of the alpha/beta-tubulin heterodimer. This study associates mutations in TUBB2A with the spectrum of "tubulinopathy" phenotypes. As a consequence, genetic variations affecting all beta-tubulin genes expressed at high levels in the brain (TUBB2B, TUBB3, TUBB, TUBB4A, and TUBB2A) have been linked with malformations of cortical development.
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Affiliation(s)
- Thomas D Cushion
- Neurology and Molecular Neuroscience Research Group, Institute of Life Science, College of Medicine, Swansea University, Swansea SA2 8PP, UK
| | - Alex R Paciorkowski
- Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642, USA; Departments of Pediatrics and Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14641, USA; Center for Neural Development & Disease, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Daniela T Pilz
- Institute of Medical Genetics, University Hospital of Wales, Cardiff CF14 4XW, UK; Wales Epilepsy Research Network (WERN), College of Medicine, Swansea University, Swansea SA2 8PP, UK
| | - Jonathan G L Mullins
- Neurology and Molecular Neuroscience Research Group, Institute of Life Science, College of Medicine, Swansea University, Swansea SA2 8PP, UK
| | - Laurie E Seltzer
- Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Robert W Marion
- The Children's Hospital at Montefiore, Bronx, NY 10467-2403, USA
| | - Emily Tuttle
- Center for Neural Development & Disease, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Dalia Ghoneim
- Center for Neural Development & Disease, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Susan L Christian
- Center for Integrative Brain Research, Seattle Children's Hospital, Seattle, WA 98101, USA
| | - Seo-Kyung Chung
- Neurology and Molecular Neuroscience Research Group, Institute of Life Science, College of Medicine, Swansea University, Swansea SA2 8PP, UK; Wales Epilepsy Research Network (WERN), College of Medicine, Swansea University, Swansea SA2 8PP, UK
| | - Mark I Rees
- Neurology and Molecular Neuroscience Research Group, Institute of Life Science, College of Medicine, Swansea University, Swansea SA2 8PP, UK; Wales Epilepsy Research Network (WERN), College of Medicine, Swansea University, Swansea SA2 8PP, UK.
| | - William B Dobyns
- Center for Integrative Brain Research, Seattle Children's Hospital, Seattle, WA 98101, USA; Departments of Pediatrics and Neurology, University of Washington, Seattle, WA 98195, USA.
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Stottmann RW, Donlin M, Hafner A, Bernard A, Sinclair DA, Beier DR. A mutation in Tubb2b, a human polymicrogyria gene, leads to lethality and abnormal cortical development in the mouse. Hum Mol Genet 2013; 22:4053-63. [PMID: 23727838 DOI: 10.1093/hmg/ddt255] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human cortical malformations, including lissencephaly, polymicrogyria and other diseases of neurodevelopment, have been associated with mutations in microtubule subunits and microtubule-associated proteins. Here we report our cloning of the brain dimple (brdp) mouse mutation, which we recovered from an ENU screen for recessive perinatal phenotypes affecting neurodevelopment. We identify the causal mutation in the tubulin, beta-2b (Tubb2b) gene as a missense mutation at a highly conserved residue (N247S). Brdp/brdp homozygous mutants have significant thinning of the cortical epithelium, which is markedly more severe in the caudo-lateral portion of the telencephalon, and do not survive past birth. The cortical defects are largely due to a major increase in apoptosis and we note abnormal proliferation of the basal progenitors. Adult brdp/+ mice are viable and fertile but exhibit behavioral phenotypes. This allele of Tubb2b represents the most severely affected mouse tubulin phenotype reported to date and this is the first report of a tubulin mutation affecting neuronal proliferation and survival.
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Affiliation(s)
- R W Stottmann
- Present address: Divisions of Human Genetics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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