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Yu T, Flores-Solis D, Eastep GN, Becker S, Zweckstetter M. Phosphatidylserine-dependent structure of synaptogyrin remodels the synaptic vesicle membrane. Nat Struct Mol Biol 2023:10.1038/s41594-023-01004-9. [PMID: 37217654 DOI: 10.1038/s41594-023-01004-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 04/21/2023] [Indexed: 05/24/2023]
Abstract
Synaptic vesicles are small membrane-enclosed organelles that store neurotransmitters at presynaptic terminals. The uniform morphology of synaptic vesicles is important for brain function, because it enables the storage of well-defined amounts of neurotransmitters and thus reliable synaptic transmission. Here, we show that the synaptic vesicle membrane protein synaptogyrin cooperates with the lipid phosphatidylserine to remodel the synaptic vesicle membrane. Using NMR spectroscopy, we determine the high-resolution structure of synaptogyrin and identify specific binding sites for phosphatidylserine. We further show that phosphatidylserine binding changes the transmembrane structure of synaptogyrin and is critical for membrane bending and the formation of small vesicles. Cooperative binding of phosphatidylserine to both a cytoplasmic and intravesicular lysine-arginine cluster in synaptogyrin is required for the formation of small vesicles. Together with other synaptic vesicle proteins, synaptogyrin thus can sculpt the membrane of synaptic vesicles.
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Affiliation(s)
- Taekyung Yu
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | | | - Gunnar N Eastep
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Stefan Becker
- Department for NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.
- Department for NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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Santarelli DM, Carroll AP, Cairns HM, Tooney PA, Cairns MJ. Schizophrenia-associated MicroRNA-Gene Interactions in the Dorsolateral Prefrontal Cortex. GENOMICS PROTEOMICS & BIOINFORMATICS 2020; 17:623-634. [PMID: 32006661 PMCID: PMC7212302 DOI: 10.1016/j.gpb.2019.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 10/01/2019] [Accepted: 10/23/2019] [Indexed: 12/14/2022]
Abstract
Schizophrenia-associated anomalies in gene expression in postmortem brain can be attributed to a combination of genetic and environmental influences. Given the small effect size of common variants, it is likely that we may only see the combined impact of some of these at the pathway level in small postmortem studies. At the gene level, however, there may be more impact from common environmental exposures mediated by influential epigenomic modifiers, such as microRNA (miRNA). We hypothesise that dysregulation of miRNAs and their alteration of gene expression have significant implications in the pathophysiology of schizophrenia. In this study, we integrate changes in cortical gene and miRNA expression to identify regulatory interactions and networks associated with the disorder. Gene expression analysis in post-mortem prefrontal dorsolateral cortex (BA 46) (n = 74 matched pairs of schizophrenia, schizoaffective, and control samples) was integrated with miRNA expression in the same cohort to identify gene-miRNA regulatory networks. A significant gene-miRNA interaction network was identified, including miR-92a, miR-495, and miR-134, which converged with differentially expressed genes in pathways involved in neurodevelopment and oligodendrocyte function. The capacity for miRNA to directly regulate gene expression through respective binding sites in BCL11A, PLP1, and SYT11 was also confirmed to support the biological relevance of this integrated network model. The observations in this study support the hypothesis that miRNA dysregulation is an important factor in the complex pathophysiology of schizophrenia.
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Affiliation(s)
- Danielle M Santarelli
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; Centre for Brain and Mental Health Research, Hunter Medical Research Institute, Newcastle, NSW 2305, Australia
| | - Adam P Carroll
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; Centre for Brain and Mental Health Research, Hunter Medical Research Institute, Newcastle, NSW 2305, Australia
| | - Heath M Cairns
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; Centre for Brain and Mental Health Research, Hunter Medical Research Institute, Newcastle, NSW 2305, Australia
| | - Paul A Tooney
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; Centre for Brain and Mental Health Research, Hunter Medical Research Institute, Newcastle, NSW 2305, Australia
| | - Murray J Cairns
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia; Centre for Brain and Mental Health Research, Hunter Medical Research Institute, Newcastle, NSW 2305, Australia.
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Abstract
Sustained neuronal communication relies on the coordinated activity of multiple proteins that regulate synaptic vesicle biogenesis and cycling within the presynaptic terminal. Synaptogyrin and synaptophysin are conserved MARVEL domain-containing transmembrane proteins that are among the most abundant synaptic vesicle constituents, although their role in the synaptic vesicle cycle has remained elusive. To further investigate the function of these proteins, we generated and characterized a synaptogyrin (gyr)-null mutant in Drosophila, whose genome encodes a single synaptogyrin isoform and lacks a synaptophysin homolog. We demonstrate that Drosophila synaptogyrin plays a modulatory role in synaptic vesicle biogenesis at larval neuromuscular junctions. Drosophila lacking synaptogyrin are viable and fertile and have no overt deficits in motor function. However, ultrastructural analysis of gyr larvae revealed increased synaptic vesicle diameter and enhanced variability in the size of synaptic vesicles. In addition, the resolution of endocytic cisternae into synaptic vesicles in response to strong stimulation is defective in gyr mutants. Electrophysiological analysis demonstrated an increase in quantal size and a concomitant decrease in quantal content, suggesting functional consequences for transmission caused by the loss of synaptogyrin. Furthermore, high-frequency stimulation resulted in increased facilitation and a delay in recovery from synaptic depression, indicating that synaptic vesicle exo-endocytosis is abnormally regulated during intense stimulation conditions. These results suggest that synaptogyrin modulates the synaptic vesicle exo-endocytic cycle and is required for the proper biogenesis of synaptic vesicles at nerve terminals.
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Kranz TM, Ekawardhani S, Lin MK, Witzmann SR, Streit F, Schuelter U, Bauer H, Henseler D, Turner JD, Muller CP, Reif A, Schote AB, Meyer J. The chromosome 15q14 locus for bipolar disorder and schizophrenia: is C15orf53 a major candidate gene? J Psychiatr Res 2012; 46:1414-20. [PMID: 22944046 DOI: 10.1016/j.jpsychires.2012.08.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 06/10/2012] [Accepted: 08/10/2012] [Indexed: 10/27/2022]
Abstract
Bipolar disorder (BD) and schizophrenia are complexly inherited and highly heritable disorders with currently unknown etiologies. Recently, two independent genome-wide association studies for BD identified a small region on chromosome 15q14-15.1, pointing to a locus close to the gene C15orf53. Previously, this genomic region was also found to co-segregate with periodic catatonia (SCZD10, OMIM %605419), an unsystematic schizophrenia according to Leonhard's classification, in several multiplex families, thus pointing to overlapping etiologies of both conditions. A susceptibility locus on chromosome 15q14-15.1 was narrowed down to a 4.38 Mb region in these affected families followed by mutation and segregation analyses of C15orf53. Association analysis of individuals affected by BD and/or SCZD10 (n = 274) and controls (n = 230) and expression analyses in distinct post-mortem human limbic brain tissues were conducted. C15orf53 revealed no mutations in our SCZD10 family members, but segregation of two common haplotypes was found. No association of identified haplotypes was found in our case-control samples. Gene expression could be demonstrated for immune-system-derived cells but not for the post-mortem human limbic brain tissue. Our results indicate that C15orf53 is probably neither causative for the etiology of BD nor for SCZD10 in our samples.
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Affiliation(s)
- Thorsten M Kranz
- Department of Neurobehavioral Genetics, Institute of Psychobiology, University of Trier, Johanniterufer 15, 54290 Trier, Germany.
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Abstract
Schizophrenia (SZ) is a common disorder that runs in families. It has a relatively high heritability, i.e., inherited factors account for the major proportion of its etiology. The high heritability has motivated gene mapping studies that have improved in sophistication through the past two decades. Belying earlier expectations, it is now becoming increasingly clear that the cause of SZ does not reside in a single mutation, or even in a single gene. Rather, there are multiple DNA variants, not all of which have been identified. Additional risk may be conferred by interactions between individual DNA variants, as well as 'gene-environment' interactions. We review studies that have accounted for a fraction of the heritability. Their relevance to the practising clinician is discussed. We propose that continuing research in DNA variation, in conjunction with rapid ongoing advances in allied fields, will yield dividends from the perspective of diagnosis, treatment prediction through pharmacogenetics, and rational treatment through discoveries in pathogenesis.
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Affiliation(s)
- Prachi Kukshal
- Department of Genetics, University of Delhi South Campus, New Delhi, India
| | - B. K. Thelma
- Department of Genetics, University of Delhi South Campus, New Delhi, India
| | - Vishwajit L. Nimgaonkar
- Departments of Psychiatry and Human Genetics, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine and Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Smita N. Deshpande
- Department of Psychiatry, Post Graduate Institute of Medical Education and Research, Dr Ram Manohar Lohia Hospital, New Delhi, India
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Löw C, Jegerschöld C, Kovermann M, Moberg P, Nordlund P. Optimisation of over-expression in E. coli and biophysical characterisation of human membrane protein synaptogyrin 1. PLoS One 2012; 7:e38244. [PMID: 22675529 PMCID: PMC3365889 DOI: 10.1371/journal.pone.0038244] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 05/02/2012] [Indexed: 11/25/2022] Open
Abstract
Progress in functional and structural studies of integral membrane proteins (IMPs) is lacking behind their soluble counterparts due to the great challenge in producing stable and homogeneous IMPs. Low natural abundance, toxicity when over-expressed and potential lipid requirements of IMPs are only a few reasons for the limited progress. Here, we describe an optimised workflow for the recombinant over-expression of the human tetraspan vesicle protein (TVP) synaptogyrin in Escherichia coli and its biophysical characterisation. TVPs are ubiquitous and abundant components of vesicles. They are believed to be involved in various aspects of the synaptic vesicle cycle, including vesicle biogenesis, exocytosis and endocytotic recycling. Even though TVPs are found in most cell types, high-resolution structural information for this class of membrane proteins is still missing. The optimisation of the N-terminal sequence of the gene together with the usage of the recently developed Lemo21(DE3) strain which allows the balancing of the translation with the membrane insertion rate led to a 50-fold increased expression rate compared to the classical BL21(DE3) strain. The protein was soluble and stable in a variety of mild detergents and multiple biophysical methods confirmed the folded state of the protein. Crosslinking experiments suggest an oligomeric architecture of at least four subunits. The protein stability is significantly improved in the presence of cholesteryl hemisuccinate as judged by differential light scattering. The approach described here can easily be adapted to other eukaryotic IMPs.
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Affiliation(s)
- Christian Löw
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- * E-mail: (CL); (PN)
| | - Caroline Jegerschöld
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Michael Kovermann
- Institut für Physik, Biophysik, Martin-Luther-Universität Halle-Wittenberg, Saale, Germany
| | - Per Moberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Pär Nordlund
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- * E-mail: (CL); (PN)
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Sohur US, Arlotta P, Macklis JD. Developmental Controls are Re-Expressed during Induction of Neurogenesis in the Neocortex of Young Adult Mice. Front Neurosci 2012; 6:12. [PMID: 22347158 PMCID: PMC3272649 DOI: 10.3389/fnins.2012.00012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 01/18/2012] [Indexed: 11/13/2022] Open
Abstract
Whether induction of low-level neurogenesis in normally non-neurogenic regions of the adult brain mimics aspects of developmental neurogenesis is currently unknown. Previously, we and others identified that biophysically induced, neuron subtype-specific apoptosis in mouse neocortex results in induction of neurogenesis of limited numbers of subtype-appropriate projection neurons with axonal projections to either thalamus or spinal cord, depending on the neuron subtype activated to undergo targeted apoptosis. Here, we test the hypothesis that developmental genes from embryonic corticogenesis are re-activated, and that some of these genes might underlie induction of low-level adult neocortical neurogenesis. We directly investigated this hypothesis via microarray analysis of microdissected regions of young adult mouse neocortex undergoing biophysically activated targeted apoptosis of neocortical callosal projection neurons. We compared the microarray results identifying differentially expressed genes with public databases of embryonic developmental genes. We find that, following activation of subtype-specific neuronal apoptosis, three distinct sets of normal developmental genes are selectively re-expressed in neocortical regions of induced neurogenesis in young adult mice: (1) genes expressed by subsets of progenitors and immature neurons in the developing ventricular and/or subventricular zones; (2) genes normally expressed by developmental radial glial progenitors; and (3) genes involved in synaptogenesis. Together with previous results, the data indicate that at least some developmental molecular controls over embryonic neurogenesis can be re-activated in the setting of induction of neurogenesis in the young adult neocortex, and suggest that some of these activate and initiate adult neuronal differentiation from endogenous progenitor populations. Understanding molecular mechanisms contributing to induced adult neurogenesis might enable directed CNS repair.
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Affiliation(s)
- U Shivraj Sohur
- Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute, Harvard University Cambridge, MA, USA
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Synaptogyrin-dependent modulation of synaptic neurotransmission in Caenorhabditis elegans. Neuroscience 2011; 190:75-88. [DOI: 10.1016/j.neuroscience.2011.05.069] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 05/20/2011] [Accepted: 05/28/2011] [Indexed: 01/31/2023]
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Abstract
BACKGROUND For many years, the prevailing paradigm has stated that in each individual with schizophrenia (SZ) the genetic risk is due to a combination of many genetic variants, individually of small effect. Recent empirical data are prompting a re-evaluation of this polygenic, common disease-common variant (CDCV) model. Evidence includes a lack of the expected strong positive findings from genome-wide association studies and the concurrent discovery of many different mutations that individually strongly predispose to SZ and other psychiatric disorders. This has led some to adopt a mixed model wherein some cases are caused by polygenic mechanisms and some by single mutations. This model runs counter to a substantial body of theoretical literature that had supposedly conclusively rejected Mendelian inheritance with genetic heterogeneity. Here we ask how this discrepancy between theory and data arose and propose a rationalization of the recent evidence base. METHOD In light of recent empirical findings, we reconsider the methods and conclusions of early theoretical analyses and the explicit assumptions underlying them. RESULTS We show that many of these assumptions can now be seen to be false and that the model of genetic heterogeneity is consistent with observed familial recurrence risks, endophenotype studies and other population-wide parameters. CONCLUSIONS We argue for a more biologically consilient mixed model that involves interactions between disease-causing and disease-modifying variants in each individual. We consider the implications of this model for moving SZ research beyond statistical associations to pathogenic mechanisms.
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Affiliation(s)
- K J Mitchell
- Smurfit Institute of Genetics, Trinity College Dublin, Ireland.
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Association study and mutational screening of SYNGR1 as a candidate susceptibility gene for schizophrenia. Psychiatr Genet 2009; 19:237-43. [DOI: 10.1097/ypg.0b013e32832cebf7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Gupta M, Bhatnagar P, Grover S, Kaur H, Baghel R, Bhasin Y, Chauhan C, Verma B, Manduva V, Mukherjee O, Purushottam M, Sharma A, Jain S, Brahmachari SK, Kukreti R. Association studies of catechol-O-methyltransferase (COMT) gene with schizophrenia and response to antipsychotic treatment. Pharmacogenomics 2009; 10:385-97. [PMID: 19290789 DOI: 10.2217/14622416.10.3.385] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
AIM We investigated the catechol-O-methyltrasferase (COMT) gene, which is a strong functional and positional candidate gene for schizophrenia and therapeutic response to antipsychotic medication. MATERIALS & METHODS Single-locus as well as detailed haplotype-based association analysis of the COMT gene with schizophrenia and antipsychotic treatment response was carried out using seven COMT polymorphisms in 398 schizophrenia patients and 241 healthy individuals from a homogeneous south Indian population. Further responsiveness to risperidone treatment was assessed in 117 schizophrenia patients using Clinical Global Impressions (CGI). A total of 69 patients with a CGI score of 2 or less met the criteria of good responders and 48 were patients who continued to have a score of 3 and above and were classified as poor responders to risperidone treatment. RESULTS The association of SNP rs4680 with schizophrenia did not remain significant after adjusting for multiple testing. Haplotype analysis showed highly significant association of seven COMT marker haplotypes with schizophrenia (CLUMP T4 p-value = 0.0001). Our results also demonstrated initial significant allelic associations of two SNPs with drug response (rs4633: chi(2) = 4.36, p-value = 0.036, OR: 1.80, 95% CI: 1.03-3.15; and rs4680: chi(2) = 4.02, p-value = 0.044, OR: 1.76, 95% CI: 1.01-3.06) before multiple correction. We employed two-marker sliding window analysis for haplotype association and observed a significant association of markers located between intron 1 and intron 2 (rs737865, rs6269: CLUMP T4 p-value = 0.021); and in exon 4 (rs4818, rs4680: CLUMP T4 p-value = 0.028) with drug response. CONCLUSION The present study thus indicates that the interacting effects within the COMT gene polymorphisms may influence the disease status and response to risperidone in schizophrenia patients. However, the study needs to be replicated in a larger sample set for confirmation, followed by functional studies.
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Affiliation(s)
- Meenal Gupta
- Institute of Genomics and Integrative Biology, Delhi, India
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Liu YL, Fann CSJ, Liu CM, Chen WJ, Wu JY, Hung SI, Chen CH, Jou YS, Liu SK, Hwang TJ, Hsieh MH, Chang CC, Yang WC, Lin JJ, Chou FHC, Faraone SV, Tsuang MT, Hwu HG. RASD2, MYH9, and CACNG2 genes at chromosome 22q12 associated with the subgroup of schizophrenia with non-deficit in sustained attention and executive function. Biol Psychiatry 2008; 64:789-96. [PMID: 18571626 DOI: 10.1016/j.biopsych.2008.04.035] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 04/21/2008] [Accepted: 04/21/2008] [Indexed: 02/03/2023]
Abstract
BACKGROUND In a previous linkage study of schizophrenia that included Taiwanese samples, the marker D22S278 (22q12.3) was significantly linked to schizophrenia (p = .001). METHODS We conducted fine mapping of the implicated genomic region, with 47 validated single nucleotide polymorphism (SNP) markers around 1 Mb of D22S278, in a Taiwanese sample of 218 pedigrees with at least 2 siblings affected with schizophrenia. We examined the association of these SNPs and their haplotypes with schizophrenia and with subgroups defined by the presence and absence of deficits in sustained attention as assessed by undegraded and degraded continuous performance tests (CPTs). We also examined subgroups defined by deficits in categories achieved in the Wisconsin Card Sort Test (WCST). RESULTS Three of five candidate vulnerability genes (RASD2, APOL5, MYH9, EIF3S7, and CACNG2), which had marginally significant associations with schizophrenia, had significant associations with schizophrenic patients who did not have deficits in sustained attention on the undegraded CPT (RASD2 gene SNP rs736212; p = .0008 with single locus analysis) and the degraded CPT (MYH9 gene haplotype 1-1-1-1 of SNP rs3752463 - rs1557540 - rs713839 - rs739097; p = .0059 with haplotype analysis). We also found a significant association for patients who showed no deficits in executive function as measured by categories achieved in the WCST (CACNG2 gene haplotype 2-1-1-1 of SNP rs2267360 - rs140526 - rs1883987 - rs916269; p = .0163 with haplotype analysis). CONCLUSIONS The genes RASD2, MYH9, and CACNG2 might be vulnerability genes for neuropsychologically defined subgroups of schizophrenic patients.
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Affiliation(s)
- Yu-Li Liu
- Division of Mental Health and Substance Abuse Research, National Health Research Institutes, Taipei, Taiwan
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Abstract
Analyses of frequency profiles of markers on disease or drug-response related genes in diverse populations are important for the dissection of common diseases. We report the results of analyses of data on 405 SNPs from 75 such genes and a 5.2 Mb chromosome, 22 genomic region in 1871 individuals from diverse 55 endogamous Indian populations. These include 32 large (>10 million individuals) and 23 isolated populations, representing a large fraction of the people of India. We observe high levels of genetic divergence between groups of populations that cluster largely on the basis of ethnicity and language. Indian populations not only overlap with the diversity of HapMap populations, but also contain population groups that are genetically distinct. These data and results are useful for addressing stratification and study design issues in complex traits especially for heterogeneous populations.
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Friedman JI, Vrijenhoek T, Markx S, Janssen IM, van der Vliet WA, Faas BHW, Knoers NV, Cahn W, Kahn RS, Edelmann L, Davis KL, Silverman JM, Brunner HG, van Kessel AG, Wijmenga C, Ophoff RA, Veltman JA. CNTNAP2 gene dosage variation is associated with schizophrenia and epilepsy. Mol Psychiatry 2008; 13:261-6. [PMID: 17646849 DOI: 10.1038/sj.mp.4002049] [Citation(s) in RCA: 243] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A homozygous mutation of the CNTNAP2 gene has been associated with a syndrome of focal epilepsy, mental retardation, language regression and other neuropsychiatric problems in children of the Old Order Amish community. Here we report genomic rearrangements resulting in haploinsufficiency of the CNTNAP2 gene in association with epilepsy and schizophrenia. Genomic deletions of varying sizes affecting the CNTNAP2 gene were identified in three non-related Caucasian patients. In contrast, we did not observe any dosage variation for this gene in 512 healthy controls. Moreover, this genomic region has not been identified as showing large-scale copy number variation. Our data thus confirm an association of CNTNAP2 to epilepsy outside the Old Order Amish population and suggest that dosage alteration of this gene may lead to a complex phenotype of schizophrenia, epilepsy and cognitive impairment.
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Affiliation(s)
- J I Friedman
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA
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Cheng MC, Chen CH. Identification of rare mutations of synaptogyrin 1 gene in patients with schizophrenia. J Psychiatr Res 2007; 41:1027-31. [PMID: 17049558 DOI: 10.1016/j.jpsychires.2006.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 07/25/2006] [Accepted: 08/30/2006] [Indexed: 10/24/2022]
Abstract
Synaptogyrin 1 gene (SYNGR1) is considered as a positional candidate gene for schizophrenia because of its location at chromosome 22q13, a region linked to schizophrenia, and its reduced expression in postmortem brain of patients with schizophrenia. Additionally, genetic studies also reported association of SYNGR1 is with schizophrenia and bipolar disorder in southern India. Prompted by these findings, we were interested to know if SYNGR1 is also associated with schizophrenia in our population. Therefore, we systematically searched for SYNGR1 mutations in a cohort of Han Chinese patients from Taiwan. Four single nucleotide polymorphisms (SNPs) were identified, including three at the putative core promoter region (g.-673A>C, g.-377G>A and g.-318G>T) that are in strong linkage disequilibrium and one in intron 2 (IVS2-64C>G). Computer program predicts that g.-637A>C and g.318G>T may change transcription binding sites of AP-1 and TGT3, respectively. We further carried out SNP- and haplotype-based case-control association studies of these tress SNPs with schizophrenia. However, no association was detected between these SNPs and schizophrenia in our sample. Nevertheless, we identified several rare mutations in exon 6 of SYNGR1 gene in our patient cohort (n=497), including a 3-bp (AAC) in-frame insertion between codon 202 and 203 (P202_T203insN) in two patients, an A-to-G missense mutation (c.665A>G) at codon 222 (D222G) in one patient, a synonymous mutation (c.669C>T) at codon 223 (T223T) in one patient, and a C-to-T at 3' UTR of SYNGR1 (c.772C>T) in one patient. These are mutations were not found in 507 control subjects, suggesting further functional assays are warranted to verify their relevance to the pathogenesis of schizophrenia.
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Affiliation(s)
- Min-Chih Cheng
- Institute of Medical Sciences, Tzu-Chi University, Hualien City 970, Taiwan
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Gupta S, Bisht SS, Kukreti R, Jain S, Brahmachari SK. Boolean network analysis of a neurotransmitter signaling pathway. J Theor Biol 2006; 244:463-9. [PMID: 17010384 DOI: 10.1016/j.jtbi.2006.08.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 06/17/2006] [Accepted: 08/22/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND A Boolean network is a simple computational model that may provide insight into the overall behavior of genetic networks and is represented by variables with two possible states (on/off), of the individual nodes/genes of the network. In this study, a Boolean network model has been used to simulate a molecular pathway between two neurotransmitter receptor, dopamine and glutamate receptor, systems in order to understand the consequence of using logic gate rules between nodes, which have two possible states (active and inactive). RESULTS The dynamical properties of this Boolean network model of the biochemical pathway shows that, the pathway is stable and that, deletion/knockout of certain biologically important nodes cause significant perturbation to this network. The analysis clearly shows that in addition to the expected components dopamine and dopamine receptor 2 (DRD2), Ca(2+) ions play a critical role in maintaining stability of the pathway. CONCLUSION So this method may be useful for the identification of potential genetic targets, whose loss of function in biochemical pathways may be responsible for disease onset. The molecular pathway considered in this study has been implicated with a complex disorder like schizophrenia, which has a complex multifactorial etiology.
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Affiliation(s)
- Simone Gupta
- Institute of Genomics and Integrative Biology, CSIR, Delhi 110007, India
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Verma R, Kubendran S, Das SK, Jain S, Brahmachari SK. SYNGR1 is associated with schizophrenia and bipolar disorder in southern India. J Hum Genet 2005; 50:635-40. [PMID: 16215643 DOI: 10.1007/s10038-005-0307-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Accepted: 08/23/2005] [Indexed: 11/26/2022]
Abstract
Chromosome 22q11-13 is one of the most consistent linkage regions for schizophrenia (SCZ) and bipolar disorder (BPAD). The SYNGR1 gene, which is associated with presynaptic vesicles in neuronal cells, is located on 22q13.1. We have previously identified a novel nonsense mutation in the SYNGR1 gene in a SCZ pedigree. In the present study, a detailed analysis of this gene was performed in a case-control cohort (198 BPAD, 193 SCZ and 107 controls from southern India) to test for association with SCZ and BPAD. Sequence analysis of all exonic and flanking intronic regions of the SYNGR1 gene in 198 BPAD and 193 SCZ cases revealed a novel mutation Lsy99Glu (in one BPAD patient) and two other novel common polymorphisms [synonymous single nucleotide polymorphism (SNP--Ser97Ser) and an Asn ins/del] in the SYNGR1 gene. We also validated 9 out of 14 dbSNPs in our population. Case-control analysis revealed allelic (P = 0.028-0.00007) association of five polymorphisms with SCZ and/or BPAD cases. Further, 3-SNP (with LD block 1 SNPs) and 2-SNP (with LD block 2 SNPs) haplotype analyses did not show any association with either SCZ or BPAD. Our results support SYNGR1 as a probable susceptibility gene for SCZ and BPAD. Also, the observed association of SYNGR1 with both SCZ and BPAD suggests the likely involvement of a common pathway in the etiology of these disorders.
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Affiliation(s)
- Ranjana Verma
- Functional Genomics Unit, Institute of Genomics and Integrative Biology (CSIR), Delhi University Campus, Mall Road, Delhi, 110007, India
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The Indian Genome Variation database (IGVdb): a project overview. Hum Genet 2005; 118:1-11. [PMID: 16133172 DOI: 10.1007/s00439-005-0009-9] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Accepted: 05/26/2005] [Indexed: 12/15/2022]
Abstract
Indian population, comprising of more than a billion people, consists of 4693 communities with several thousands of endogamous groups, 325 functioning languages and 25 scripts. To address the questions related to ethnic diversity, migrations, founder populations, predisposition to complex disorders or pharmacogenomics, one needs to understand the diversity and relatedness at the genetic level in such a diverse population. In this backdrop, six constituent laboratories of the Council of Scientific and Industrial Research (CSIR), with funding from the Government of India, initiated a network program on predictive medicine using repeats and single nucleotide polymorphisms. The Indian Genome Variation (IGV) consortium aims to provide data on validated SNPs and repeats, both novel and reported, along with gene duplications, in over a thousand genes, in 15,000 individuals drawn from Indian subpopulations. These genes have been selected on the basis of their relevance as functional and positional candidates in many common diseases including genes relevant to pharmacogenomics. This is the first large-scale comprehensive study of the structure of the Indian population with wide-reaching implications. A comprehensive platform for Indian Genome Variation (IGV) data management, analysis and creation of IGVdb portal has also been developed. The samples are being collected following ethical guidelines of Indian Council of Medical Research (ICMR) and Department of Biotechnology (DBT), India. This paper reveals the structure of the IGV project highlighting its various aspects like genesis, objectives, strategies for selection of genes, identification of the Indian subpopulations, collection of samples and discovery and validation of genetic markers, data analysis and monitoring as well as the project's data release policy.
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Verma R, Mukerji M, Grover D, B-Rao C, Das SK, Kubendran S, Jain S, Brahmachari SK. MLC1 gene is associated with schizophrenia and bipolar disorder in Southern India. Biol Psychiatry 2005; 58:16-22. [PMID: 15992519 DOI: 10.1016/j.biopsych.2005.03.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Revised: 03/02/2005] [Accepted: 03/16/2005] [Indexed: 11/24/2022]
Abstract
BACKGROUND Chromosome 22q13 has shown linkage with schizophrenia (SCZ) and bipolar affective disorder (BPAD). A missense mutation in MLC1 (putative cation-channel gene on 22q13) co-segregating with periodic catatonic schizophrenia has been reported. We have investigated the relationship of MLC1 with SCZ and BPAD in Southern India. METHODS All exons and flanking intronic sequences of MLC1 were screened for novel variations. Case-control (216 BPAD, 193 SCZ, 116 control subjects) and family-based analyses (113 BPAD, 107 SCZ families) were performed to evaluate association of MLC1 with these disorders. RESULTS We found 33 MLC1 sequence variations, including three novel mutations: Val210Ile, Leu308Gln, and Arg328His in six BPAD cases and Val210Ile in one control individual. Minor allele of a common variation, ss16339182 (in approximately 6 Kb Linkage-Disequilibrium [LD]-block) was associated with BPAD in case-control (p = .03) and family-based analyses (transmitted/nontransmitted [T/NT]-44/20; p = .003). Association was observed for rs2235349 and rs2076137 with SCZ and ss16339163 with BPAD in case-control study. Using Block 2 haplotype tagging single nucleotide polymorphisms (htSNPs), GC haplotype revealed association (p = .02) and excess transmission (p = .002) with BPAD. CONCLUSIONS Association of MLC1 with SCZ and BPAD suggests involvement of a common pathway. Rare missense mutations and common variants associated with BPAD favors hypothesis about likely involvement of both rare and common polymorphisms in etiology of this complex disorder.
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Affiliation(s)
- Ranjana Verma
- Functional Genomics Unit, Institute of Genomics and Integrative Biology (CSIR), Delhi, India
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Belfort GM, Bakirtzi K, Kandror KV. Cellugyrin induces biogenesis of synaptic-like microvesicles in PC12 cells. J Biol Chem 2004; 280:7262-72. [PMID: 15590695 DOI: 10.1074/jbc.m404851200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The four-transmembrane domain proteins synaptophysin and synaptogyrin represent the major constituents of synaptic vesicles. Our previous studies in PC12 cells demonstrated that synaptogyrin or its nonneuronal paralog cellugyrin targets efficiently to synaptic-like microvesicles (SLMVs) and dramatically increases the synaptophysin content of SLMVs (Belfort, G. M., and Kandror, K. V. (2003) J. Biol. Chem. 278, 47971-47978). Here, we explored the mechanism of these phenomena and found that ectopic expression of cellugyrin increases the number of SLMVs in PC12 cells. Mutagenesis studies revealed that cellugyrin's hydrophilic cytoplasmic domains are not involved in vesicle biogenesis, whereas small conserved hydrophobic hairpins in the first luminal loop and the carboxyl terminus of cellugyrin were found to be critical for the formation of SLMVs. In addition, the length but not the primary sequence of the second luminal loop was essential for SLMV biogenesis. We suggest that changing the length of this loop similar to disruption of the short hydrophobic hairpins alters the position of the vicinal transmembrane domains that may be crucial for protein function.
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Affiliation(s)
- Gabriel M Belfort
- Boston University School of Medicine, Boston, Massachusetts 02118, USA
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