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Hamada N, Iwamoto I, Nagata KI. MED13L and its disease-associated variants influence the dendritic development of cerebral cortical neurons in the mammalian brain. J Neurochem 2023; 165:334-347. [PMID: 36798993 DOI: 10.1111/jnc.15783] [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: 06/14/2022] [Revised: 11/04/2022] [Accepted: 02/13/2023] [Indexed: 02/18/2023]
Abstract
The mediator complex comprises multiple subcellular subunits that collectively function as a molecular interface between RNA polymerase II and gene-specific transcription factors. Recently, genetic variants to one subunit of the complex, known as MED13L (mediator complex subunit 13 like), have been implicated in syndromic intellectual disability and distinct facial features, frequently accompanied by congenital heart defects. We investigated the impact of five disease-associated MED13L variants on the subcellular localization and biochemical stability of MED13L protein in vitro and in vivo. In overexpression assays using cortical neurons from embryonic mouse cerebral cortices transduced by in utero electroporation-mediated gene transfer, we found that mouse orthologues of human MED13L-p.P866L and -p.T2162M missense variants accumulated in the nucleus, while the p.S2163L and p.S2177Y variants were diffusely distributed in the cytoplasm. In contrast, we found that the p.Q1922* truncation variant was barely detectable in transduced cells, a phenotype reminiscent of this variant that results in MED13L haploinsufficiency in humans. Next, we analyzed these variants for their effects on neuronal migration, dendritic growth, spine morphology, and axon elongation of cortical neurons in vivo. There, we found that overexpression of the p.P866L variant resulted in reduced number and length of dendrites of cortical layer II/III pyramidal neurons. Furthermore, we show that mMED13L-knockdown abrogated dendritic growth in vivo, and this effect was significantly rescued by co-electroporation of an RNAi-resistant mMED13L, but weakly by the p.T2162M variant, and not at all by the p.S2163L variant. However, overexpression of the p.S2163L variant inhibited mature dendritic spine formation in vivo. Expression of each of the 5 variants did not affect neuronal cell migration and callosal axon elongation in vivo. Taken together, our results demonstrate that MED13L expression is relevant to corticogenesis and influences the dendritic branching characteristics of cortical excitatory neurons. Our study also suggests that disease-associated MED13L variants may directly cause morphological and functional defects in cortical neurons in different ways.
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Affiliation(s)
- Nanako Hamada
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Ikuko Iwamoto
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan.,Department of Neurochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Hamada N, Noda M, Ito H, Iwamoto I, Nagata KI. Expression analyses of Cep152, a responsible gene product for autosomal recessive primary microcephaly, during mouse brain development. Dev Neurosci 2022; 44:162-170. [PMID: 35259752 DOI: 10.1159/000523922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 03/01/2022] [Indexed: 11/19/2022] Open
Abstract
Centrosomal protein 152 (Cep152) regulates centriole duplication as a molecular scaffold during the cell cycle. Its gene abnormalities are responsible for autosomal recessive primary microcephaly 9 (MCPH9) and Seckel syndrome. In this study, we prepared an antibody against mouse Cep152, anti-Cep152, and performed expression analyses focusing on mouse brain development. Western blotting analyses revealed that Cep152 with a molecular mass of ~150 kDa was expressed strongly at embryonic day (E) 13 and then gradually decreased during the brain development process. Instead, protein bands of ~80 kDa and ~60 kDa came to be recognized after postnatal day (P)15 and P30, respectively. In immunohistochemical analyses, Cep152 was enriched in the centrosome of neuronal progenitors in the ventricular zone at E14, whereas it was diffusely distributed mainly in the cytoplasm of cortical neurons at P18. In developing cerebellum at P7, Cep152 was localized at the centrosome in the external granular layer, where neurogenesis takes place. Notably, biochemical analysis revealed that Cep152 was also present in the post-synaptic density fraction. Subsequent immunofluorescent analyses showed co-localization of Cep152 with excitatory synaptic markers, PSD-95 and synaptophysin, but not with an inhibitory synaptic marker gephyrin in differentiated primary cultured hippocampal neurons. The obtained results suggest that Cep152 takes part not only in neurogenesis during corticogenesis but also in the regulation of synaptic function in differentiated neurons.
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Affiliation(s)
- Nanako Hamada
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Mariko Noda
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Hidenori Ito
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Ikuko Iwamoto
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
- Department of Neurochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Wayhelova M, Vallova V, Broz P, Mikulasova A, Loubalova D, Filkova H, Smetana J, Drabova K, Gaillyova R, Kuglik P. Novel de novo pathogenic variant in the GNAI1 gene as a cause of severe disorders of intellectual development. J Hum Genet 2021; 67:209-214. [PMID: 34819662 DOI: 10.1038/s10038-021-00988-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/09/2022]
Abstract
Pathogenic sequence variant in the GNAI1 gene were recently introduced as a cause of novel syndrome with a manifestation of variable developmental delay and autistic features. In our study, we report a case of monozygotic twins with severe intellectual disability and motor delay and developmental dysphasia. Both probands and their parents were examined using multi-step molecular diagnostic algorithm including whole-exome sequencing (WES), resulting in the identification of a novel, de novo pathogenic sequence variant in the GNAI1 gene, NM_002069.6:c.815 A>G, p.(Asp272Gly) in probands. Using WES we also verified the microarray findings of a familial 8q24.23q24.3 duplication and heterozygous 5q13.2 deletion, not associated with clinical symptoms in probands. Our results confirmed the role of the GNAI1 gene in the pathogenesis of syndromic neurodevelopmental disorders. They support trio- or quatro-based WES as a suitable molecular diagnostics method for the simultaneous detection of clinically relevant sequence variants and CNVs in individuals with neurodevelopmental disorders and rare diseases.
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Affiliation(s)
- Marketa Wayhelova
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic. .,Laboratory of Cytogenomics, Centre of Molecular Biology and Genetics, Department of Internal Medicine, Haematology and Oncology, University Hospital Brno, Brno, Czech Republic. .,Department of Medical Genetics and Genomics, University Hospital Brno, Brno, Czech Republic.
| | - Vladimira Vallova
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Laboratory of Cytogenomics, Centre of Molecular Biology and Genetics, Department of Internal Medicine, Haematology and Oncology, University Hospital Brno, Brno, Czech Republic
| | - Petr Broz
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University Prague and Faculty Hospital Motol, Prague, Czech Republic
| | - Aneta Mikulasova
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Dominika Loubalova
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Hana Filkova
- Laboratory of Cytogenomics, Centre of Molecular Biology and Genetics, Department of Internal Medicine, Haematology and Oncology, University Hospital Brno, Brno, Czech Republic
| | - Jan Smetana
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Klara Drabova
- Department of Medical Genetics and Genomics, University Hospital Brno, Brno, Czech Republic
| | - Renata Gaillyova
- Department of Medical Genetics and Genomics, University Hospital Brno, Brno, Czech Republic
| | - Petr Kuglik
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic. .,Laboratory of Cytogenomics, Centre of Molecular Biology and Genetics, Department of Internal Medicine, Haematology and Oncology, University Hospital Brno, Brno, Czech Republic.
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