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Radu R, Petrescu GED, Gorgan RM, Brehar FM. GFAPδ: A Promising Biomarker and Therapeutic Target in Glioblastoma. Front Oncol 2022; 12:859247. [PMID: 35372061 PMCID: PMC8971704 DOI: 10.3389/fonc.2022.859247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 02/24/2022] [Indexed: 12/02/2022] Open
Abstract
GFAPδ, the delta isoform of the glial fibrillary acidic protein, is mainly expressed in the subventricular zone of the brain, together with other neural stem cell markers like nestin. The authors of this paper were among the first that described in detail the expression of GFAPδ and its correlation with malignancy and invasiveness in cerebral astrocytoma. Later, several papers confirmed these findings, showing that the alternative splice variant GFAPδ is overexpressed in glioblastoma (CNS WHO grade 4) compared with lower grade gliomas. Other studies suggested that a high GFAPδ/α ratio is associated with a more malignant and invasive behavior of glioma cells. Moreover, the changing of GFAPδ/α ratio affects the expression of high-malignant genes. It is now suggested that discriminating between predominant GFAP isoforms, GFAPδ or GFAPα, is useful for assessing the malignancy state of astrocytoma, and may even contribute to the classification of gliomas. Therefore, the purpose of this paper is to review the literature with emphasize on the role of GFAPδ as a potential biomarker, and as a possible therapeutic target in glioblastoma.
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Affiliation(s)
- Roxana Radu
- Department of Neurosurgery, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Neurosurgery, Bagdasar-Arseni Clinical Emergency Hospital, Bucharest, Romania
| | - George E. D. Petrescu
- Department of Neurosurgery, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Neurosurgery, Bagdasar-Arseni Clinical Emergency Hospital, Bucharest, Romania
- *Correspondence: George E. D. Petrescu,
| | - Radu M. Gorgan
- Department of Neurosurgery, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Neurosurgery, Bagdasar-Arseni Clinical Emergency Hospital, Bucharest, Romania
| | - Felix M. Brehar
- Department of Neurosurgery, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- Department of Neurosurgery, Bagdasar-Arseni Clinical Emergency Hospital, Bucharest, Romania
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2
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van Asperen JV, Robe PA, Hol EM. GFAP Alternative Splicing and the Relevance for Disease – A Focus on Diffuse Gliomas. ASN Neuro 2022; 14:17590914221102065. [PMID: 35673702 PMCID: PMC9185002 DOI: 10.1177/17590914221102065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Glial fibrillary acidic protein (GFAP) is an intermediate filament protein that is
characteristic for astrocytes and neural stem cells, and their malignant analogues in
glioma. Since the discovery of the protein 50 years ago, multiple alternative splice
variants of the GFAP gene have been discovered, leading to different GFAP isoforms. In
this review, we will describe GFAP isoform expression from gene to protein to network,
taking the canonical isoforms GFAPα and the main alternative variant GFAPδ as the starting
point. We will discuss the relevance of studying GFAP and its isoforms in disease, with a
specific focus on diffuse gliomas.
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Affiliation(s)
- Jessy V. van Asperen
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Pierre A.J.T. Robe
- Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, University Utrecht, Utrecht, The Netherlands
| | - Elly M. Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
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3
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Abstract
Fifty years have passed since the discovery of glial fibrillary acidic protein (GFAP) by Lawrence Eng and colleagues. Now recognized as a member of the intermediate filament family of proteins, it has become a subject for study in fields as diverse as structural biology, cell biology, gene expression, basic neuroscience, clinical genetics and gene therapy. This review covers each of these areas, presenting an overview of current understanding and controversies regarding GFAP with the goal of stimulating continued study of this fascinating protein.
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Affiliation(s)
- Albee Messing
- Waisman Center, University of Wisconsin-Madison.,Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison
| | - Michael Brenner
- Department of Neurobiology, University of Alabama-Birmingham
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4
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Abstract
Alexander disease is a rare and generally fatal disorder of the central nervous system, originally defined by the distinctive neuropathology consisting of abundant Rosenthal fibers within the cytoplasm and processes of astrocytes. More recently, mutations in GFAP, encoding glial fibrillary acidic protein, the major intermediate filament protein of astrocytes, have been identified in nearly all patients. No other genetic causes have yet been identified. The precise mechanisms by which mutations lead to disease are poorly understood. Despite the genetic homogeneity, there are a wide range of clinical phenotypes. The genetic issues and the approach to diagnosis are the prime consideration in this chapter.
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Affiliation(s)
- Albee Messing
- Waisman Center and Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, United States.
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5
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Thomsen R, Daugaard TF, Holm IE, Nielsen AL. Alternative mRNA splicing from the glial fibrillary acidic protein (GFAP) gene generates isoforms with distinct subcellular mRNA localization patterns in astrocytes. PLoS One 2013; 8:e72110. [PMID: 23991052 PMCID: PMC3753360 DOI: 10.1371/journal.pone.0072110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/06/2013] [Indexed: 11/20/2022] Open
Abstract
The intermediate filament network of astrocytes includes Glial fibrillary acidic protein (Gfap) as a major component. Gfap mRNA is alternatively spliced resulting in generation of different protein isoforms where Gfapα is the most predominant isoform. The Gfapδ isoform is expressed in proliferating neurogenic astrocytes of the developing human brain and in the adult human and mouse brain. Here we provide a characterization of mouse Gfapδ mRNA and Gfapδ protein. RT-qPCR analysis showed that Gfapδ mRNA and Gfapα mRNA expression is coordinately increased in the post-natal period. Immunohistochemical staining of developing mouse brain samples showed that Gfapδ is expressed in the sub-ventricular zones in accordance with the described localization in the developing and adult human brain. Immunofluorescence analysis verified incorporation of Gfapδ into the Gfap intermediate filament network and overlap in Gfapδ and Gfapα subcellular localization. Subcellular mRNA localization studies identified different localization patterns of Gfapδ and Gfapα mRNA in mouse primary astrocytes. A larger fraction of Gfapα mRNA showed mRNA localization to astrocyte protrusions compared to Gfapδ mRNA. The differential mRNA localization patterns were dependent on the different 3′-exon sequences included in Gfapδ and Gfapα mRNA. The presented results show that alternative Gfap mRNA splicing results in isoform-specific mRNA localization patterns with resulting different local mRNA concentration ratios which have potential to participate in subcellular region-specific intermediate filament dynamics during brain development, maintenance and in disease.
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Affiliation(s)
- Rune Thomsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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6
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Mamber C, Kamphuis W, Haring NL, Peprah N, Middeldorp J, Hol EM. GFAPδ expression in glia of the developmental and adolescent mouse brain. PLoS One 2012; 7:e52659. [PMID: 23285135 PMCID: PMC3528700 DOI: 10.1371/journal.pone.0052659] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 11/20/2012] [Indexed: 11/19/2022] Open
Abstract
Glial fibrillary acidic protein (GFAP) is the major intermediate filament (IF) protein in astrocytes. In the human brain, GFAP isoforms have unique expression patterns, which indicate that they play distinct functional roles. One isoform, GFAPδ, is expressed by proliferative radial glia in the developing human brain. In the adult human, GFAPδ is a marker for neural stem cells. However, it is unknown whether GFAPδ marks the same population of radial glia and astrocytes in the developing mouse brain as it does in the developing human brain. This study characterizes the expression pattern of GFAPδ throughout mouse embryogenesis and into adolescence. Gfapδ transcripts are expressed from E12, but immunohistochemistry shows GFAPδ staining only from E18. This finding suggests a translational uncoupling. GFAPδ expression increases from E18 to P5 and then decreases until its expression plateaus around P25. During development, GFAPδ is expressed by radial glia, as denoted by the co-expression of markers like vimentin and nestin. GFAPδ is also expressed in other astrocytic populations during development. A similar pattern is observed in the adolescent mouse, where GFAPδ marks both neural stem cells and mature astrocytes. Interestingly, the Gfapδ/Gfapα transcript ratio remains stable throughout development as well as in primary astrocyte and neurosphere cultures. These data suggest that all astroglia cells in the developing and adolescent mouse brain express GFAPδ, regardless of their neurogenic capabilities. GFAPδ may be an integral component of all mouse astrocytes, but it is not a specific neural stem cell marker in mice as it is in humans.
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Affiliation(s)
- Carlyn Mamber
- Department of Astrocyte Biology & Neurodegeneration, Netherlands Institute for Neuroscience - an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Willem Kamphuis
- Department of Astrocyte Biology & Neurodegeneration, Netherlands Institute for Neuroscience - an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Nina L. Haring
- Department of Astrocyte Biology & Neurodegeneration, Netherlands Institute for Neuroscience - an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Nuzrat Peprah
- Department of Astrocyte Biology & Neurodegeneration, Netherlands Institute for Neuroscience - an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Jinte Middeldorp
- Department of Astrocyte Biology & Neurodegeneration, Netherlands Institute for Neuroscience - an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, United States of America
| | - Elly M. Hol
- Department of Astrocyte Biology & Neurodegeneration, Netherlands Institute for Neuroscience - an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
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7
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Katz ML, Sanders DN, Mooney BP, Johnson GS. Accumulation of glial fibrillary acidic protein and histone H4 in brain storage bodies of Tibetan terriers with hereditary neuronal ceroid lipofuscinosis. J Inherit Metab Dis 2007; 30:952-63. [PMID: 18004671 DOI: 10.1007/s10545-007-0683-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Revised: 09/20/2007] [Accepted: 10/04/2007] [Indexed: 11/26/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are inherited neurodegenerative diseases characterized by massive accumulation of autofluorescent storage bodies in neurons and other cells. A late-onset form of NCL occurs in Tibetan terrier dogs. Gel electrophoretic analyses of isolated storage body proteins from brains of affected dogs indicated that a protein of approximately 50 kDa was consistently prominent and a 16 kDa component was present in some brain storage body preparations. Mass spectral analysis identified the 50 kDa protein as glial fibrillary acidic protein (GFAP), isoform 2. GFAP identification was supported by immunoblot and immunohistochemical analyses. Histone H4 was the major protein in the 16 kDa component. Specific accumulation of GFAP and histone H4 in storage bodies has not been previously reported for any of the NCLs. Tibetan terrier NCL may be the canine correlate of one of the human adult-onset NCLs for which the genetic bases and storage body compositions have not yet been determined.
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Affiliation(s)
- M L Katz
- Mason Eye Institute, University of Missouri School of Medicine, One Hospital Dr., Columbia, MO 65212, USA.
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8
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Blechingberg J, Holm IE, Nielsen KB, Jensen TH, Jørgensen AL, Nielsen AL. Identification and characterization of GFAPkappa, a novel glial fibrillary acidic protein isoform. Glia 2007; 55:497-507. [PMID: 17203480 DOI: 10.1002/glia.20475] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glial fibrillary acidic protein (GFAP) is the principal component of the intermediary filaments in mature astrocytes of the central nervous system (CNS). The protein consists of three domains: the head, the coiled-coil, and the tail. Here, we describe the isolation of an evolutionary conserved novel GFAP isoform, GFAPkappa, produced by alternative splicing and polyadenylation of the 3'-region of the human GFAP pre-mRNA. As a consequence, the resulting human GFAPkappa protein harbors a nonconserved C-terminal tail sequence distinct from the tails of GFAPalpha, the predominant GFAP isoform, and GFAPepsilon, an isoform which also results from alternative splicing. The head and coiled-coil rod domains are identical between the three GFAP isoforms. Interestingly, GFAPkappa is incapable of forming homomeric filaments, and increasing GFAPkappa expression levels causes a collapse of intermediate filaments formed by GFAPalpha. In searching for a biological relevance of GFAPkappa, we noticed that mRNA expression levels of GFAPalpha, GFAPepsilon, and GFAPkappa are gradually increased during development of the embryonic pig brain. However, whereas the GFAPalpha/GFAPepsilon ratio is constant, the GFAPkappa/GFAPepsilon ratio decreases during brain development. Furthermore, in glioblastoma tumors, an increased GFAPkappa/GFAPepsilon ratio is detected. Our results suggest that the relative expression level of the GFAPkappa isoform could modulate the properties of GFAP intermediate filaments and perhaps thereby influencing the motility of GFAP positive astrocytes and progenitor cells within the CNS.
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Affiliation(s)
- Jenny Blechingberg
- Institute of Human Genetics, The Bartholin Building, University of Aarhus, Aarhus C DK-8000, Denmark
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9
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Li R, Johnson AB, Salomons GS, van der Knaap MS, Rodriguez D, Boespflug-Tanguy O, Gorospe JR, Goldman JE, Messing A, Brenner M. Propensity for paternal inheritance of de novo mutations in Alexander disease. Hum Genet 2005; 119:137-44. [PMID: 16365765 DOI: 10.1007/s00439-005-0116-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Accepted: 11/29/2005] [Indexed: 01/22/2023]
Abstract
De novo dominant mutations in the GFAP gene have recently been associated with nearly all cases of Alexander disease, a rare but devastating neurological disorder. These heterozygous mutations must occur very early in development and be present in nearly all cells in order to be detected by the sequencing methods used. To investigate whether the mutations may have arisen in the parental germ lines, we determined the parental chromosome bearing the mutations for 28 independent Alexander disease cases. These cases included 17 different missense mutations and one insertion mutation. To enable assignment of the chromosomal origin of the mutations, six new single nucleotide polymorphisms in the GFAP gene were identified, bringing the known total to 26. In 24 of the 28 cases analyzed, the paternal chromosome carried the GFAP mutation (P < 0.001), suggesting that they predominantly arose in the parental germ line, with most occurring during spermatogenesis. No effect of paternal age was observed. There has been considerable debate about the magnitude of the male to female germ line mutation rate; our ratio of 6:1 is consistent with indirect estimates based on the rate of evolution of the sex chromosome relative to the autosomic chromosomes.
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Affiliation(s)
- Rong Li
- Department of Neurobiology and Civitan International Research Center 529, University of Alabama at Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294-0021, USA
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10
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Roelofs RF, Fischer DF, Houtman SH, Sluijs JA, Van Haren W, Van Leeuwen FW, Hol EM. Adult human subventricular, subgranular, and subpial zones contain astrocytes with a specialized intermediate filament cytoskeleton. Glia 2005; 52:289-300. [PMID: 16001427 DOI: 10.1002/glia.20243] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Human glial fibrillary acidic protein-delta (GFAP-delta) is a GFAP protein isoform that is encoded by an alternative splice variant of the GFAP-gene. As a result, GFAP-delta protein differs from the predominant splice form, GFAP-alpha, by its C-terminal protein sequence. In this study, we show that GFAP-delta protein is not expressed by all GFAP-expressing astrocytes but specifically by a subpopulation located in the subpial zone of the cerebral cortex, the subgranular zone of the hippocampus, and, most intensely, by a ribbon of astrocytes following the ependymal layer of the cerebral ventricles. Therefore, at least in the sub ventricular zone (SVZ), GFAP-delta specifically marks the population of astrocytes that contain the neural stem cells in the adult human brain. Interestingly, the SVZ astrocytes actively splice GFAP-delta transcripts, in contrast to astrocytes adjacent to this layer. Furthermore, we show that GFAP-delta protein, unlike GFAP-alpha, is not upregulated in astrogliosis. Our data therefore indicate a different functional role for GFAP-delta in astrocyte physiology. Finally, transfection studies showed that GFAP-delta protein expression has a negative effect on GFAP filament formation, and therefore could be important for modulating intermediate filament cytoskeletal properties, possibly facilitating astrocyte motility. Further studies on GFAP-delta and the cells that express it are important for gaining insights into its function during differentiation, migration and during health and disease.
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Affiliation(s)
- Reinko F Roelofs
- Netherlands Institute for Brain Research, Graduate School Neurosciences, Amsterdam, the Netherlands
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11
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Yang JW, Juranville JF, Höger H, Fountoulakis M, Lubec G. Molecular diversity of rat brain proteins as revealed by proteomic analysis. Mol Divers 2005; 9:385-96. [PMID: 16311815 DOI: 10.1007/s11030-005-6359-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 11/08/2004] [Indexed: 11/28/2022]
Abstract
Multiple protein expression forms (MPEFs) presenting splicing forms or co- and posttranslation modifications, account for the vast diversity, the myriad of gene products and clearly indicate problems which proteomics research is facing. In the present study, we generated a rat brain map representing MPEFs by the use of an analytical method based on two-dimensional electrophoresis combined with mass spectrometry. Forty-nine individual proteins were selected that showed more than two spots, resulting altogether into a total number of 357 expression forms. Some proteins showed large MPEFs numbers as e.g. tubulin alpha-1 chain (24 spots), ATP synthase alpha-chain (28), beta chain (17) or septin 7 (13). The molecular diversity observed in this map clearly shows that immunochemical or even protein chemical results from expressional studies have to be interpreted with caution, in particular if one dimensional electrophoretic or western blot techniques are applied and MPEFs are poorly resolved.
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Affiliation(s)
- Jae-Won Yang
- Department of Pediatrics, University of Vienna, Vienna, Austria
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Dos Santos PC, Gottfried C, Gehlen G, Gonçalves CA, Achaval M. Distribution and ontogeny of glial fibrillary acidic protein in the snail Megalobulimus abbreviatus. Comp Biochem Physiol A Mol Integr Physiol 2005; 141:140-5. [PMID: 15951212 DOI: 10.1016/j.cbpb.2005.04.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2004] [Revised: 12/15/2004] [Accepted: 02/25/2005] [Indexed: 11/19/2022]
Abstract
Glial fibrillary acidic protein (GFAP) is the major component of intermediate glial filaments in the central nervous system of many vertebrates and invertebrates. In vertebrates, this protein is mainly expressed in mature astrocytes and provides structural cell stability. The highly conserved structure and glial specificity of this protein have allowed studies of ontogeny and phylogeny using antibodies. The present study investigated the ontogenetic profile and molecular weight of GFAP in the snail, Megalobulimus abbreviatus, particularly in cerebral ganglia and subesophageal mass, by immunohistochemistry and immunoblotting. Our results confirm and extend previous studies about glial intermediate filaments in snails, showing: (i) a higher GFAP content in cerebral ganglia than in subesophageal mass; (ii) a developmental increase of GFAP immunocontent in cerebral ganglia, as described in Vertebrates; and (iii) an electrophoretic band for GFAP of approximately 55 kDa.
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Affiliation(s)
- Paula C Dos Santos
- Departamentos de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Brazil.
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13
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Nielsen AL, Jørgensen AL. Self-assembly of the cytoskeletal glial fibrillary acidic protein is inhibited by an isoform-specific C terminus. J Biol Chem 2004; 279:41537-45. [PMID: 15284230 DOI: 10.1074/jbc.m406601200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The predominant isoform of glial fibrillary acidic protein (GFAP), GFAPalpha, is the characteristic building block of the cytoskeletal intermediate filaments in astrocytes. Isoform GFAPepsilon, produced by alternative splicing of the GFAP gene, includes a new tail domain that confers a presenilin binding capacity. We here show that the GFAPepsilon tail prevents GFAPepsilon homodimerization and homomeric filament formation, whereas the ability to form heterodimers and filaments with GFAPalpha is retained. Furthermore, GFAPepsilon shows decreased affinity for several GFAPalpha-interacting proteins. A GFAPepsilon tail mutation that results in gain of GFAPepsilon dimerization and filament formation abolishes presenilin binding. This mutation also abolishes interaction between the tail and the coiled-coil domain of GFAPepsilon. Together, this indicates that direct interaction between the coiled-coil and tail domains may serve as an inhibitory mechanism for homomeric dimerization and filament formation. We propose that the GFAPepsilon isoform represents a new functionally distinct component of GFAP intermediate filaments.
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Affiliation(s)
- Anders Lade Nielsen
- Department of Human Genetics, Bartholin Building, University of Aarhus, DK-8000 Aarhus C, Denmark.
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14
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Nielsen AL, Jørgensen AL. Structural and functional characterization of the zebrafish gene for glial fibrillary acidic protein, GFAP. Gene 2003; 310:123-32. [PMID: 12801639 DOI: 10.1016/s0378-1119(03)00526-2] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Glial fibrillary acidic protein, GFAP, is an astrocyte-specific member of the family of intermediate filament proteins which are involved in formation of the cytoskeletal structure. We here present a characterization of the zebrafish GFAP gene and corresponding protein. The zebrafish GFAP gene have the same exon-intron organization as the mammalian orthologoue genes. Comparison of the protein with mammalian GFAP shows that the amino acid sequence is highly conserved in the rod and tail domains whereas the head domain has diverged. Zebrafish GFAP exhibits functional characteristics of an intermediate filament protein such as dimerization potential, capacity to assembly into filaments, and cytoskeletal localization. Mutations in human GFAP have been associated with a severe childhood brain disorder called Alexander disease. Interestingly, the mutations affect preferentially amino acid residues of GFAP that are evolutionarily conserved. This indicates that a change of functionally core residues in GFAP is a prerequisite for the disease phenotype to develop and the initial steps in the pathogenesis may thus be modeled in zebrafish.
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Affiliation(s)
- Anders Lade Nielsen
- Department of Human Genetics, The Bartholin Building, University of Aarhus, DK-8000, Aarhus C, Denmark.
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