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Stojkovic M, Petrovic M, Capovilla M, Milojevic S, Makevic V, Budimirovic DB, Corscadden L, He S, Protic D. Using a Combination of Novel Research Tools to Understand Social Interaction in the Drosophila melanogaster Model for Fragile X Syndrome. BIOLOGY 2024; 13:432. [PMID: 38927312 PMCID: PMC11200401 DOI: 10.3390/biology13060432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 05/31/2024] [Accepted: 06/06/2024] [Indexed: 06/28/2024]
Abstract
Fragile X syndrome (FXS), the most common monogenic cause of inherited intellectual disability and autism spectrum disorder, is caused by a full mutation (>200 CGG repeats) in the Fragile X Messenger Ribonucleoprotein 1 (FMR1) gene. Individuals with FXS experience various challenges related to social interaction (SI). Animal models, such as the Drosophila melanogaster model for FXS where the only ortholog of human FMR1 (dFMR1) is mutated, have played a crucial role in the understanding of FXS. The aim of this study was to investigate SI in the dFMR1B55 mutants (the groups of flies of both sexes simultaneously) using the novel Drosophila Shallow Chamber and a Python data processing pipeline based on social network analysis (SNA). In comparison with wild-type flies (w1118), SNA analysis in dFMR1B55 mutants revealed hypoactivity, fewer connections in their networks, longer interaction duration, a lower ability to transmit information efficiently, fewer alternative pathways for information transmission, a higher variability in the number of interactions they achieved, and flies tended to stay near the boundaries of the testing chamber. These observed alterations indicate the presence of characteristic strain-dependent social networks in dFMR1B55 flies, commonly referred to as the group phenotype. Finally, combining novel research tools is a valuable method for SI research in fruit flies.
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Affiliation(s)
- Maja Stojkovic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (M.S.); (S.M.)
| | - Milan Petrovic
- Department of Informatics, University of Rijeka, 51000 Rijeka, Croatia;
- Center for Artificial Intelligence and Cybersecurity, University of Rijeka, 51000 Rijeka, Croatia
| | - Maria Capovilla
- UMR7275 CNRS-UCA, Institut de Pharmacologie Moléculaire et Cellulaire, 06560 Valbonne Sophia Antipolis, France;
| | - Sara Milojevic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (M.S.); (S.M.)
| | - Vedrana Makevic
- Department of Pathophysiology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;
| | - Dejan B. Budimirovic
- Department of Psychiatry, Fragile X Clinic, Kennedy Krieger Institute, Baltimore, MD 21205, USA;
- Department of Psychiatry & Behavioral Sciences-Child Psychiatry, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | | | - Shuhan He
- Lab of Computer Science, Department of Internal Medicine, Harvard Medical School, Boston, MA 02115, USA;
| | - Dragana Protic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (M.S.); (S.M.)
- Fragile X Clinic, Special Hospital for Cerebral Palsy and Developmental Neurology, 11000 Belgrade, Serbia
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2
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Trajković J, Makevic V, Pesic M, Pavković-Lučić S, Milojevic S, Cvjetkovic S, Hagerman R, Budimirovic DB, Protic D. Drosophila melanogaster as a Model to Study Fragile X-Associated Disorders. Genes (Basel) 2022; 14:genes14010087. [PMID: 36672829 PMCID: PMC9859539 DOI: 10.3390/genes14010087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/30/2022] Open
Abstract
Fragile X syndrome (FXS) is a global neurodevelopmental disorder caused by the expansion of CGG trinucleotide repeats (≥200) in the Fragile X Messenger Ribonucleoprotein 1 (FMR1) gene. FXS is the hallmark of Fragile X-associated disorders (FXD) and the most common monogenic cause of inherited intellectual disability and autism spectrum disorder. There are several animal models used to study FXS. In the FXS model of Drosophila, the only ortholog of FMR1, dfmr1, is mutated so that its protein is missing. This model has several relevant phenotypes, including defects in the circadian output pathway, sleep problems, memory deficits in the conditioned courtship and olfactory conditioning paradigms, deficits in social interaction, and deficits in neuronal development. In addition to FXS, a model of another FXD, Fragile X-associated tremor/ataxia syndrome (FXTAS), has also been established in Drosophila. This review summarizes many years of research on FXD in Drosophila models.
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Affiliation(s)
- Jelena Trajković
- Faculty of Biology, University of Belgrade, 11000 Belgrade, Serbia
| | - Vedrana Makevic
- Department of Pathophysiology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Milica Pesic
- Institute of Human Genetics, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | | | - Sara Milojevic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Smiljana Cvjetkovic
- Department of Humanities, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Randi Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, 2825 50th Street, Sacramento, CA 95817, USA
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA
| | - Dejan B. Budimirovic
- Department of Psychiatry, Fragile X Clinic, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Psychiatry & Behavioral Sciences-Child Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Dragana Protic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
- Correspondence:
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3
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Titus MB, Wright EG, Bono JM, Poliakon AK, Goldstein BR, Super MK, Young LA, Manaj M, Litchford M, Reist NE, Killian DJ, Olesnicky EC. The conserved alternative splicing factor caper regulates neuromuscular phenotypes during development and aging. Dev Biol 2021; 473:15-32. [PMID: 33508255 PMCID: PMC7987824 DOI: 10.1016/j.ydbio.2021.01.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/17/2022]
Abstract
RNA-binding proteins play an important role in the regulation of post-transcriptional gene expression throughout the nervous system. This is underscored by the prevalence of mutations in genes encoding RNA splicing factors and other RNA-binding proteins in a number of neurodegenerative and neurodevelopmental disorders. The highly conserved alternative splicing factor Caper is widely expressed throughout the developing embryo and functions in the development of various sensory neural subtypes in the Drosophila peripheral nervous system. Here we find that caper dysfunction leads to aberrant neuromuscular junction morphogenesis, as well as aberrant locomotor behavior during larval and adult stages. Despite its widespread expression, our results indicate that caper function is required to a greater extent within the nervous system, as opposed to muscle, for neuromuscular junction development and for the regulation of adult locomotor behavior. Moreover, we find that Caper interacts with the RNA-binding protein Fmrp to regulate adult locomotor behavior. Finally, we show that caper dysfunction leads to various phenotypes that have both a sex and age bias, both of which are commonly seen in neurodegenerative disorders in humans.
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Affiliation(s)
- M Brandon Titus
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Ethan G Wright
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Jeremy M Bono
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Andrea K Poliakon
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Brandon R Goldstein
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Meg K Super
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Lauren A Young
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Melpomeni Manaj
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Morgan Litchford
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Noreen E Reist
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Darrell J Killian
- Department of Molecular Biology, Colorado College, Colorado Springs, CO, 80903, USA
| | - Eugenia C Olesnicky
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA.
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Abstract
Drosophila melanogaster males reduce courtship behaviour after mating failure. In the lab, such conditioned courtship suppression, aka 'courtship conditioning', serves as a complex learning and memory assay. Interestingly, variations in the courtship conditioning assay can establish different types of memory. Here, we review research investigating the underlying cellular and molecular mechanisms that allow male flies to form memories of previous mating failures.
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Affiliation(s)
- Nicholas Raun
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Spencer Jones
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jamie M Kramer
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
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5
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Andrew DR, Moe ME, Chen D, Tello JA, Doser RL, Conner WE, Ghuman JK, Restifo LL. Spontaneous motor-behavior abnormalities in two Drosophila models of neurodevelopmental disorders. J Neurogenet 2020; 35:1-22. [PMID: 33164597 DOI: 10.1080/01677063.2020.1833005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Mutations in hundreds of genes cause neurodevelopmental disorders with abnormal motor behavior alongside cognitive deficits. Boys with fragile X syndrome (FXS), a leading monogenic cause of intellectual disability, often display repetitive behaviors, a core feature of autism. By direct observation and manual analysis, we characterized spontaneous-motor-behavior phenotypes of Drosophila dfmr1 mutants, an established model for FXS. We recorded individual 1-day-old adult flies, with mature nervous systems and prior to the onset of aging, in small arenas. We scored behavior using open-source video-annotation software to generate continuous activity timelines, which were represented graphically and quantitatively. Young dfmr1 mutants spent excessive time grooming, with increased bout number and duration; both were rescued by transgenic wild-type dfmr1+. By two grooming-pattern measures, dfmr1-mutant flies showed elevated repetitions consistent with perseveration, which is common in FXS. In addition, the mutant flies display a preference for grooming posterior body structures, and an increased rate of grooming transitions from one site to another. We raise the possibility that courtship and circadian rhythm defects, previously reported for dfmr1 mutants, are complicated by excessive grooming. We also observed significantly increased grooming in CASK mutants, despite their dramatically decreased walking phenotype. The mutant flies, a model for human CASK-related neurodevelopmental disorders, displayed consistently elevated grooming indices throughout the assay, but transient locomotory activation immediately after placement in the arena. Based on published data identifying FMRP-target transcripts and functional analyses of mutations causing human genetic neurodevelopmental disorders, we propose the following proteins as candidate mediators of excessive repetitive behaviors in FXS: CaMKIIα, NMDA receptor subunits 2A and 2B, NLGN3, and SHANK3. Together, these fly-mutant phenotypes and mechanistic insights provide starting points for drug discovery to identify compounds that reduce dysfunctional repetitive behaviors.
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Affiliation(s)
- David R Andrew
- Department of Neurology, University of Arizona Health Sciences, Tucson, AZ, USA.,Center for Insect Science, University of Arizona, Tucson, AZ, USA.,Department of Biological Sciences, Lycoming College, Williamsport, PA, USA
| | - Mariah E Moe
- Department of Neurology, University of Arizona Health Sciences, Tucson, AZ, USA
| | - Dailu Chen
- Department of Neurology, University of Arizona Health Sciences, Tucson, AZ, USA
| | - Judith A Tello
- Department of Neurology, University of Arizona Health Sciences, Tucson, AZ, USA.,Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, USA
| | - Rachel L Doser
- Department of Neurology, University of Arizona Health Sciences, Tucson, AZ, USA
| | - William E Conner
- Department of Biology, Wake Forest University, Winston-Salem, NC, USA
| | - Jaswinder K Ghuman
- Department of Psychiatry, University of Arizona Health Sciences, Tucson, AZ, USA
| | - Linda L Restifo
- Department of Neurology, University of Arizona Health Sciences, Tucson, AZ, USA.,Center for Insect Science, University of Arizona, Tucson, AZ, USA.,Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, USA.,BIO5 Interdisciplinary Research Institute, University of Arizona, Tucson, AZ, USA
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6
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Yue XZ, Li D, Lv J, Liu K, Chen J, Zhang WQ. Involvement of mind the gap in the organization of the tracheal apical extracellular matrix in Drosophila and Nilaparvata lugens. INSECT SCIENCE 2020; 27:756-770. [PMID: 31240817 DOI: 10.1111/1744-7917.12699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 06/05/2019] [Accepted: 06/10/2019] [Indexed: 06/09/2023]
Abstract
The tracheal apical extracellular matrix (aECM) is vital for expansion of the tracheal lumen and supports the normal structure of the lumen to guarantee air entry and circulation in insects. Although it has been found that some cuticular proteins are involved in the organization of the aECM, unidentified factors still exist. Here, we found that mind the gap (Mtg), a predicted chitin-binding protein, is required for the normal formation of the apical chitin matrix of airway tubes in the model holometabolous insect Drosophila melanogaster. Similar to chitin, the Mtg protein was linearly arranged in the tracheal dorsal trunk of the tracheae in Drosophila. Decreased mtg expression in the tracheae seriously affected the viability of larvae and caused tracheal chitin spiral defects in some larvae. Analysis of mtg mutant showed that mtg was required for normal development of tracheae in embryos. Irregular taenidial folds of some mtg mutant embryos were found on either lateral view of tracheal dorsal trunk or internal view of transmission electron microscopy analysis. These abnormal tracheae were not fully filled with gas and accompanied by a reduction in tracheal width, which are characteristic phenotypes of tracheal aECM defects. Furthermore, in the hemimetabolous brown planthopper (BPH) Nilaparvata lugens, downregulation of NlCPAP1-N (a homolog of mtg) also led to the formation of abnormal tracheal chitin spirals and death. These results suggest that mtg and its homolog are involved in the proper organization of the tracheal aECMs in flies and BPH, and that this function may be conserved in insects.
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Affiliation(s)
- Xiang-Zhao Yue
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Dan Li
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jun Lv
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Kai Liu
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jie Chen
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wen-Qing Zhang
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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7
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Zafarullah M, Tang HT, Durbin-Johnson B, Fourie E, Hessl D, Rivera SM, Tassone F. FMR1 locus isoforms: potential biomarker candidates in fragile X-associated tremor/ataxia syndrome (FXTAS). Sci Rep 2020; 10:11099. [PMID: 32632326 PMCID: PMC7338407 DOI: 10.1038/s41598-020-67946-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 05/18/2020] [Indexed: 12/12/2022] Open
Abstract
Fragile X associated tremor/ataxia syndrome (FXTAS) is a late adult-onset neurodegenerative disorder that affects movement and cognition in male and female carriers of a premutation allele of 55-200 CGG repeats in the Fragile X mental retardation (FMR1) gene. It is currently unknown if and when an individual carrier of a premutation allele will develop FXTAS, as clinical assessment fails to identify carriers at risk before significant neurological symptoms are evident. The primary objective of this study was to investigate the alternative splicing landscape at the FMR1 locus in conjunction with brain measures in male individuals with a premutation allele enrolled in a very first longitudinal study, compared to age-matched healthy male controls, with the purpose of identifying biomarkers for early diagnosis, disease prediction and, a progression of FXTAS. Our findings indicate that increased expression of FMR1 mRNA isoforms, including Iso4/4b, Iso10/10b, as well as of the ASFMR1 mRNAs Iso131bp, are present in premutation carriers as compared to non-carrier healthy controls. More specifically, we observed a higher expression of Iso4/4b and Iso10/10b, which encode for truncated proteins, only in those premutation carriers who developed symptoms of FXTAS over time as compared to non-carrier healthy controls, suggesting a potential role in the development of the disorder. In addition, we found a significant association of these molecular changes with various measurements of brain morphology, including the middle cerebellar peduncle (MCP), superior cerebellar peduncle (SCP), pons, and midbrain, indicating their potential contribution to the pathogenesis of FXTAS. Interestingly, the high expression levels of Iso4/4b observed both at visit 1 and visit 2 and found to be associated with a decrease in mean MCP width only in those individuals who developed FXTAS over time, suggests their role as potential biomarkers for early diagnosis of FXTAS.
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Affiliation(s)
- Marwa Zafarullah
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, 95817 CA, USA
| | - Hiu-Tung Tang
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, 95817 CA, USA
| | - Blythe Durbin-Johnson
- Division of Biostatistics, School of Medicine, University of California Davis, Davis, CA, USA
| | - Emily Fourie
- Center for Mind and Brain, University of California Davis, Davis, CA, USA
- Department of Psychology, University of California, Davis, Davis, CA, USA
| | - David Hessl
- MIND Institute, University of California Davis Medical Center, Sacramento, 95817 CA, USA
- Department of Psychiatry and Behavioral Sciences, University of California Davis Medical Center, Sacramento, 95817 CA, USA
| | - Susan M Rivera
- Center for Mind and Brain, University of California Davis, Davis, CA, USA
- Department of Psychology, University of California, Davis, Davis, CA, USA
- MIND Institute, University of California Davis Medical Center, Sacramento, 95817 CA, USA
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, 95817 CA, USA.
- MIND Institute, University of California Davis Medical Center, Sacramento, 95817 CA, USA.
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8
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Yang WJ, Yan AZ, Xu YJ, Guo XY, Fu XG, Li D, Liao J, Zhang D, Lan FH. Further identification of a 140bp sequence from amid intron 9 of human FMR1 gene as a new exon. BMC Genet 2020; 21:63. [PMID: 32552710 PMCID: PMC7301526 DOI: 10.1186/s12863-020-00870-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 06/09/2020] [Indexed: 11/24/2022] Open
Abstract
Background The disease gene of fragile X syndrome, FMR1 gene, encodes fragile X mental retardation protein (FMRP). The alternative splicing (AS) of FMR1 can affect the structure and function of FMRP. However, the biological functions of alternatively spliced isoforms remain elusive. In a previous study, we identified a new 140bp exon from the intron 9 of human FMR1 gene. In this study, we further examined the biological functions of this new exon and its underlying signaling pathways. Results qRT-PCR results showed that this novel exon is commonly expressed in the peripheral blood of normal individuals. Comparative genomics showed that sequences paralogous to the 140 bp sequence only exist in the genomes of primates. To explore the biological functions of the new transcript, we constructed recombinant eukaryotic expression vectors and lentiviral overexpression vectors. Results showed that the spliced transcript encoded a truncated protein which was expressed mainly in the cell nucleus. Additionally, several genes, including the BEX1 gene involved in mGluR-LTP or mGluR-LTD signaling pathways were significantly influenced when the truncated FMRP was overexpressed. Conclusions our work identified a new exon from amid intron 9 of human FMR1 gene with wide expression in normal healthy individuals, which emphasizes the notion that the AS of FMR1 gene is complex and may in a large part account for the multiple functions of FMRP.
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Affiliation(s)
- Wen-Jing Yang
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.,Present addresses: Department of Laboratory Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Ai-Zhen Yan
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China
| | - Yong-Jun Xu
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China
| | - Xiao-Yan Guo
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.,Present addresses: Department of Laboratory Medicine, Fuzhou No. 2 Hospital Affiliated Xiamen University, Fuzhou, Fujian, 350007, People's Republic of China
| | - Xian-Guo Fu
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.,Present addresses: Department of Laboratory Medicine, Ningde Municipal Hospital, Fujian Medical University, Ningde City, 352100, Fujian Province, China
| | - Dan Li
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China
| | - Juan Liao
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.,Present addresses: Department of Laboratory Medicine, Fujian University of Traditional Chinese Medicine Affiliated People's Hospital, Fuzhou, 350001, Fujian, China
| | - Duo Zhang
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China
| | - Feng-Hua Lan
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.
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9
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Westmark CJ. Fragile X and APP: a Decade in Review, a Vision for the Future. Mol Neurobiol 2019; 56:3904-3921. [PMID: 30225775 PMCID: PMC6421119 DOI: 10.1007/s12035-018-1344-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/05/2018] [Indexed: 10/28/2022]
Abstract
Fragile X syndrome (FXS) is a devastating developmental disability that has profound effects on cognition, behavior, and seizure susceptibility. There are currently no treatments that target the underlying cause of the disorder, and recent clinical trials have been unsuccessful. In 2007, seminal work demonstrated that amyloid-beta protein precursor (APP) is dysregulated in Fmr1KO mice through a metabotropic glutamate receptor 5 (mGluR5)-dependent pathway. These findings raise the hypotheses that: (1) APP and/or APP metabolites are potential therapeutic targets as well as biomarkers for FXS and (2) mGluR5 inhibitors may be beneficial in the treatment of Alzheimer's disease. Herein, advances in the field over the past decade that have reproduced and greatly expanded upon these original findings are reviewed, and required experimentation to validate APP metabolites as potential disease biomarkers as well as therapeutic targets for FXS are discussed.
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Affiliation(s)
- Cara J Westmark
- Department of Neurology, University of Wisconsin-Madison, Medical Sciences Center, Room 3619, 1300 University Avenue, Madison, WI, USA.
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10
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Abstract
The Drosophila melanogaster larval neuromuscular system is extensively used by researchers to study neuronal cell biology, and Drosophila glutamatergic motor neurons have become a major model system. There are two main Types of glutamatergic motor neurons, Ib and Is, with different structural and physiological properties at synaptic level at the neuromuscular junction. To generate genetic tools to identify and manipulate motor neurons of each Type, we screened for GAL4 driver lines for this purpose. Here we describe GAL4 drivers specific for examples of neurons within each Type, Ib or Is. These drivers showed high expression levels and were expressed in only few motor neurons, making them amenable tools for specific studies of both axonal and synapse biology in identified Type I motor neurons.
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11
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Prenatal Neuropathologies in Autism Spectrum Disorder and Intellectual Disability: The Gestation of a Comprehensive Zebrafish Model. J Dev Biol 2018; 6:jdb6040029. [PMID: 30513623 PMCID: PMC6316217 DOI: 10.3390/jdb6040029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/20/2018] [Accepted: 11/27/2018] [Indexed: 12/27/2022] Open
Abstract
Autism spectrum disorder (ASD) and intellectual disability (ID) are neurodevelopmental disorders with overlapping diagnostic behaviors and risk factors. These include embryonic exposure to teratogens and mutations in genes that have important functions prenatally. Animal models, including rodents and zebrafish, have been essential in delineating mechanisms of neuropathology and identifying developmental critical periods, when those mechanisms are most sensitive to disruption. This review focuses on how the developmentally accessible zebrafish is contributing to our understanding of prenatal pathologies that set the stage for later ASD-ID behavioral deficits. We discuss the known factors that contribute prenatally to ASD-ID and the recent use of zebrafish to model deficits in brain morphogenesis and circuit development. We conclude by suggesting that a future challenge in zebrafish ASD-ID modeling will be to bridge prenatal anatomical and physiological pathologies to behavioral deficits later in life.
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12
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Drozd M, Bardoni B, Capovilla M. Modeling Fragile X Syndrome in Drosophila. Front Mol Neurosci 2018; 11:124. [PMID: 29713264 PMCID: PMC5911982 DOI: 10.3389/fnmol.2018.00124] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/29/2018] [Indexed: 01/18/2023] Open
Abstract
Intellectual disability (ID) and autism are hallmarks of Fragile X Syndrome (FXS), a hereditary neurodevelopmental disorder. The gene responsible for FXS is Fragile X Mental Retardation gene 1 (FMR1) encoding the Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein involved in RNA metabolism and modulating the expression level of many targets. Most cases of FXS are caused by silencing of FMR1 due to CGG expansions in the 5'-UTR of the gene. Humans also carry the FXR1 and FXR2 paralogs of FMR1 while flies have only one FMR1 gene, here called dFMR1, sharing the same level of sequence homology with all three human genes, but functionally most similar to FMR1. This enables a much easier approach for FMR1 genetic studies. Drosophila has been widely used to investigate FMR1 functions at genetic, cellular, and molecular levels since dFMR1 mutants have many phenotypes in common with the wide spectrum of FMR1 functions that underlay the disease. In this review, we present very recent Drosophila studies investigating FMRP functions at genetic, cellular, molecular, and electrophysiological levels in addition to research on pharmacological treatments in the fly model. These studies have the potential to aid the discovery of pharmacological therapies for FXS.
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Affiliation(s)
- Małgorzata Drozd
- Université Côte d'Azur, CNRS, IPMC, Valbonne, France.,CNRS LIA (Neogenex), Valbonne, France
| | - Barbara Bardoni
- CNRS LIA (Neogenex), Valbonne, France.,Université Côte d'Azur, INSERM, CNRS, IPMC, Valbonne, France
| | - Maria Capovilla
- Université Côte d'Azur, CNRS, IPMC, Valbonne, France.,CNRS LIA (Neogenex), Valbonne, France
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Tseng E, Tang HT, AlOlaby RR, Hickey L, Tassone F. Altered expression of the FMR1 splicing variants landscape in premutation carriers. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:1117-1126. [PMID: 28888471 DOI: 10.1016/j.bbagrm.2017.08.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/26/2017] [Accepted: 08/26/2017] [Indexed: 01/17/2023]
Abstract
FMR1 premutation carriers (55-200 CGG repeats) are at risk for developing Fragile X-associated Tremor/Ataxia Syndrome (FXTAS), an adult onset neurodegenerative disorder. Approximately 20% of female carriers will develop Fragile X-associated Primary Ovarian Insufficiency (FXPOI), in addition to a number of clinical problems affecting premutation carriers throughout their life span. Marked elevation in FMR1 mRNA levels have been observed with premutation alleles resulting in RNA toxicity, the leading molecular mechanism proposed for the FMR1 associated disorders observed in premutation carriers. The FMR1 gene undergoes alternative splicing and we have recently reported that the relative abundance of all FMR1 mRNA isoforms is significantly increased in premutation carriers. In this study, we characterized the transcriptional FMR1 isoforms distribution pattern in different tissues and identified a total of 49 isoforms, some of which observed only in premutation carriers and which might play a role in the pathogenesis of FXTAS. Further, we investigated the distribution pattern and expression levels of the FMR1 isoforms in asymptomatic premutation carriers and in those with FXTAS and found no significant differences between the two groups. Our findings suggest that the characterization of the expression levels of the different FMR1 isoforms is fundamental for understanding the regulation of the FMR1 gene as imbalance in their expression could lead to an altered functional diversity with neurotoxic consequences. Their characterization will also help to elucidating the mechanism(s) by which "toxic gain of function" of the FMR1 mRNA may play a role in FXTAS and/or in the other FMR1-associated conditions.
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Affiliation(s)
| | - Hiu-Tung Tang
- Biochemistry and Molecular Medicine, UC Davis, Sacramento, CA 95817, USA
| | - Reem Rafik AlOlaby
- Biochemistry and Molecular Medicine, UC Davis, Sacramento, CA 95817, USA
| | - Luke Hickey
- Pacific Biosciences, Inc., Menlo Park, CA 94025, USA
| | - Flora Tassone
- Biochemistry and Molecular Medicine, UC Davis, Sacramento, CA 95817, USA; MIND Institute, UC Davis, Sacramento, CA 95817, USA.
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14
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Dysregulation of mRNA Localization and Translation in Genetic Disease. J Neurosci 2017; 36:11418-11426. [PMID: 27911744 DOI: 10.1523/jneurosci.2352-16.2016] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 11/21/2022] Open
Abstract
RNA-binding proteins (RBPs) acting at various steps in the post-transcriptional regulation of gene expression play crucial roles in neuronal development and synaptic plasticity. Genetic mutations affecting several RBPs and associated factors lead to diverse neurological symptoms, as characterized by neurodevelopmental and neuropsychiatric disorders, neuromuscular and neurodegenerative diseases, and can often be multisystemic diseases. We will highlight the physiological roles of a few specific proteins in molecular mechanisms of cytoplasmic mRNA regulation, and how these processes are dysregulated in genetic disease. Recent advances in computational biology and genomewide analysis, integrated with diverse experimental approaches and model systems, have provided new insights into conserved mechanisms and the shared pathobiology of mRNA dysregulation in disease. Progress has been made to understand the pathobiology of disease mechanisms for myotonic dystrophy, spinal muscular atrophy, and fragile X syndrome, with broader implications for other RBP-associated genetic neurological diseases. This gained knowledge of underlying basic mechanisms has paved the way to the development of therapeutic strategies targeting disease mechanisms.
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Sudhakaran IP, Ramaswami M. Long-term memory consolidation: The role of RNA-binding proteins with prion-like domains. RNA Biol 2017; 14:568-586. [PMID: 27726526 PMCID: PMC5449092 DOI: 10.1080/15476286.2016.1244588] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 09/07/2016] [Accepted: 09/29/2016] [Indexed: 12/23/2022] Open
Abstract
Long-term and short-term memories differ primarily in the duration of their retention. At a molecular level, long-term memory (LTM) is distinguished from short-term memory (STM) by its requirement for new gene expression. In addition to transcription (nuclear gene expression) the translation of stored mRNAs is necessary for LTM formation. The mechanisms and functions for temporal and spatial regulation of mRNAs required for LTM is a major contemporary problem, of interest from molecular, cell biological, neurobiological and clinical perspectives. This review discusses primary evidence in support for translational regulatory events involved in LTM and a model in which different phases of translation underlie distinct phases of consolidation of memories. However, it focuses largely on mechanisms of memory persistence and the role of prion-like domains in this defining aspect of long-term memory. We consider primary evidence for the concept that Cytoplasmic Polyadenylation Element Binding (CPEB) protein enables the persistence of formed memories by transforming in prion-like manner from a soluble monomeric state to a self-perpetuating and persistent polymeric translationally active state required for maintaining persistent synaptic plasticity. We further discuss prion-like domains prevalent on several other RNA-binding proteins involved in neuronal translational control underlying LTM. Growing evidence indicates that such RNA regulatory proteins are components of mRNP (RiboNucleoProtein) granules. In these proteins, prion-like domains, being intrinsically disordered, could mediate weak transient interactions that allow the assembly of RNP granules, a source of silenced mRNAs whose translation is necessary for LTM. We consider the structural bases for RNA granules formation as well as functions of disordered domains and discuss how these complicate the interpretation of existing experimental data relevant to general mechanisms by which prion-domain containing RBPs function in synapse specific plasticity underlying LTM.
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Affiliation(s)
- Indulekha P. Sudhakaran
- National Center for Biological Sciences, TIFR, Bangalore, India
- Manipal University, Manipal, India
| | - Mani Ramaswami
- National Center for Biological Sciences, TIFR, Bangalore, India
- School of Genetics and Microbiology and School of Natural Sciences, Smurfit Institute of Genetics and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
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16
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Lozano R, Martinez-Cerdeno V, Hagerman RJ. Advances in the Understanding of the Gabaergic Neurobiology of FMR1 Expanded Alleles Leading to Targeted Treatments for Fragile X Spectrum Disorder. Curr Pharm Des 2016; 21:4972-4979. [PMID: 26365141 DOI: 10.2174/1381612821666150914121038] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/11/2015] [Indexed: 12/15/2022]
Abstract
Fragile X spectrum disorder (FXSD) includes: fragile X syndrome (FXS), fragile X-associated tremor ataxia syndrome (FXTAS) and fragile X-associated primary ovarian insufficiency (FXPOI), as well as other medical, psychiatric and neurobehavioral problems associated with the premutation and gray zone alleles. FXS is the most common monogenetic cause of autism (ASD) and intellectual disability (ID). The understanding of the neurobiology of FXS has led to many targeted treatment trials in FXS. The first wave of phase II clinical trials in FXS were designed to target the mGluR5 pathway; however the results did not show significant efficacy and the trials were terminated. The advances in the understanding of the GABA system in FXS have shifted the focus of treatment trials to GABA agonists, and a new wave of promising clinical trials is under way. Ganaxolone and allopregnanolone (GABA agonists) have been studied in individuals with FXSD and are currently in phase II trials. Both allopregnanolone and ganaxolone may be efficacious in treatment of FXS and FXTAS, respectively. Allopregnanolone, ganaxolone, riluzole, gaboxadol, tiagabine, and vigabatrin are potential GABAergic treatments. The lessons learned from the initial trials have not only shifted the targeted system, but also have refined the design of clinical trials. The results of these new trials will likely impact further clinical trials for FXS and other genetic disorders associated with ASD.
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Affiliation(s)
- Reymundo Lozano
- Icahn School of Medicine at Mount Sinai, New York, NY USA; Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY USA
| | - Veronica Martinez-Cerdeno
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA; Institute for Pediatric Regenerative Medicine and Shriners Hospital for Children of Northern California, Sacramento, CA, USA; Department of Pathology and Laboratory Medicine, UC Davis, Sacramento, USA
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA; Department of Pediatrics, UC Davis, Sacramento, CA, USA
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Choi CH, Schoenfeld BP, Bell AJ, Hinchey J, Rosenfelt C, Gertner MJ, Campbell SR, Emerson D, Hinchey P, Kollaros M, Ferrick NJ, Chambers DB, Langer S, Sust S, Malik A, Terlizzi AM, Liebelt DA, Ferreiro D, Sharma A, Koenigsberg E, Choi RJ, Louneva N, Arnold SE, Featherstone RE, Siegel SJ, Zukin RS, McDonald TV, Bolduc FV, Jongens TA, McBride SMJ. Multiple Drug Treatments That Increase cAMP Signaling Restore Long-Term Memory and Aberrant Signaling in Fragile X Syndrome Models. Front Behav Neurosci 2016; 10:136. [PMID: 27445731 PMCID: PMC4928101 DOI: 10.3389/fnbeh.2016.00136] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 06/15/2016] [Indexed: 01/01/2023] Open
Abstract
Fragile X is the most common monogenic disorder associated with intellectual disability (ID) and autism spectrum disorders (ASD). Additionally, many patients are afflicted with executive dysfunction, ADHD, seizure disorder and sleep disturbances. Fragile X is caused by loss of FMRP expression, which is encoded by the FMR1 gene. Both the fly and mouse models of fragile X are also based on having no functional protein expression of their respective FMR1 homologs. The fly model displays well defined cognitive impairments and structural brain defects and the mouse model, although having subtle behavioral defects, has robust electrophysiological phenotypes and provides a tool to do extensive biochemical analysis of select brain regions. Decreased cAMP signaling has been observed in samples from the fly and mouse models of fragile X as well as in samples derived from human patients. Indeed, we have previously demonstrated that strategies that increase cAMP signaling can rescue short term memory in the fly model and restore DHPG induced mGluR mediated long term depression (LTD) in the hippocampus to proper levels in the mouse model (McBride et al., 2005; Choi et al., 2011, 2015). Here, we demonstrate that the same three strategies used previously with the potential to be used clinically, lithium treatment, PDE-4 inhibitor treatment or mGluR antagonist treatment can rescue long term memory in the fly model and alter the cAMP signaling pathway in the hippocampus of the mouse model.
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Affiliation(s)
- Catherine H Choi
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Department of Dermatology, Dermatology Clinic, Drexel University College of MedicinePhiladelphia, PA, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
| | - Brian P Schoenfeld
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
| | - Aaron J Bell
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
| | - Joseph Hinchey
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Cory Rosenfelt
- Bolduc Laboratory, Department of Pediatrics, Center for Neuroscience, University of Alberta Edmonton, AB, Canada
| | - Michael J Gertner
- Zukin Laboratory, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Sean R Campbell
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Danielle Emerson
- Jongens Laboratory, Department of Genetics, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Paul Hinchey
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Maria Kollaros
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Neal J Ferrick
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
| | - Daniel B Chambers
- Bolduc Laboratory, Department of Pediatrics, Center for Neuroscience, University of Alberta Edmonton, AB, Canada
| | - Steven Langer
- Bolduc Laboratory, Department of Pediatrics, Center for Neuroscience, University of Alberta Edmonton, AB, Canada
| | - Steven Sust
- Siegel Laboratory, Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Aatika Malik
- Jongens Laboratory, Department of Genetics, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Allison M Terlizzi
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - David A Liebelt
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - David Ferreiro
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Ali Sharma
- Zukin Laboratory, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Eric Koenigsberg
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Richard J Choi
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Natalia Louneva
- Arnold Laboratory, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Steven E Arnold
- Arnold Laboratory, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Robert E Featherstone
- Siegel Laboratory, Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Steven J Siegel
- Siegel Laboratory, Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - R Suzanne Zukin
- Zukin Laboratory, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Thomas V McDonald
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Francois V Bolduc
- Bolduc Laboratory, Department of Pediatrics, Center for Neuroscience, University of Alberta Edmonton, AB, Canada
| | - Thomas A Jongens
- Jongens Laboratory, Department of Genetics, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Sean M J McBride
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA; Siegel Laboratory, Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
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Androschuk A, Al-Jabri B, Bolduc FV. From Learning to Memory: What Flies Can Tell Us about Intellectual Disability Treatment. Front Psychiatry 2015; 6:85. [PMID: 26089803 PMCID: PMC4453272 DOI: 10.3389/fpsyt.2015.00085] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Accepted: 05/19/2015] [Indexed: 01/13/2023] Open
Abstract
Intellectual disability (ID), previously known as mental retardation, affects 3% of the population and remains without pharmacological treatment. ID is characterized by impaired general mental abilities associated with defects in adaptive function in which onset occurs before 18 years of age. Genetic factors are increasing and being recognized as the causes of severe ID due to increased use of genome-wide screening tools. Unfortunately drug discovery for treatment of ID has not followed the same pace as gene discovery, leaving clinicians, patients, and families without the ability to ameliorate symptoms. Despite this, several model organisms have proven valuable in developing and screening candidate drugs. One such model organism is the fruit fly Drosophila. First, we review the current understanding of memory in human and its model in Drosophila. Second, we describe key signaling pathways involved in ID and memory such as the cyclic adenosine 3',5'-monophosphate (cAMP)-cAMP response element binding protein (CREB) pathway, the regulation of protein synthesis, the role of receptors and anchoring proteins, the role of neuronal proliferation, and finally the role of neurotransmitters. Third, we characterize the types of memory defects found in patients with ID. Finally, we discuss how important insights gained from Drosophila learning and memory could be translated in clinical research to lead to better treatment development.
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Affiliation(s)
- Alaura Androschuk
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
| | - Basma Al-Jabri
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
| | - Francois V. Bolduc
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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19
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Weisz ED, Monyak RE, Jongens TA. Deciphering discord: How Drosophila research has enhanced our understanding of the importance of FMRP in different spatial and temporal contexts. Exp Neurol 2015; 274:14-24. [PMID: 26026973 DOI: 10.1016/j.expneurol.2015.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 05/18/2015] [Accepted: 05/23/2015] [Indexed: 01/06/2023]
Abstract
Fragile X Syndrome (FXS) is the most common heritable form of intellectual impairment as well as the leading monogenetic cause of autism. In addition to its canonical definition as a neurodevelopmental disease, recent findings in the clinic suggest that FXS is a systemic disorder that is characterized by a variety of heterogeneous phenotypes. Efforts to study FXS pathogenesis have been aided by the development and characterization of animal models of the disease. Research efforts in Drosophila melanogaster have revealed key insights into the mechanistic underpinnings of FXS. While much remains unknown, it is increasingly apparent that FXS involves a myriad of spatially and temporally specific alterations in cellular function. Consequently, the literature is filled with numerous discordant findings. Researchers and clinicians alike must be cognizant of this dissonance, as it will likely be important for the design of preclinical studies to assess the efficacy of therapeutic strategies to improve the lives of FXS patients.
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Affiliation(s)
- Eliana D Weisz
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Rachel E Monyak
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Thomas A Jongens
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
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20
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PDE-4 inhibition rescues aberrant synaptic plasticity in Drosophila and mouse models of fragile X syndrome. J Neurosci 2015; 35:396-408. [PMID: 25568131 DOI: 10.1523/jneurosci.1356-12.2015] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Fragile X syndrome (FXS) is the leading cause of both intellectual disability and autism resulting from a single gene mutation. Previously, we characterized cognitive impairments and brain structural defects in a Drosophila model of FXS and demonstrated that these impairments were rescued by treatment with metabotropic glutamate receptor (mGluR) antagonists or lithium. A well-documented biochemical defect observed in fly and mouse FXS models and FXS patients is low cAMP levels. cAMP levels can be regulated by mGluR signaling. Herein, we demonstrate PDE-4 inhibition as a therapeutic strategy to ameliorate memory impairments and brain structural defects in the Drosophila model of fragile X. Furthermore, we examine the effects of PDE-4 inhibition by pharmacologic treatment in the fragile X mouse model. We demonstrate that acute inhibition of PDE-4 by pharmacologic treatment in hippocampal slices rescues the enhanced mGluR-dependent LTD phenotype observed in FXS mice. Additionally, we find that chronic treatment of FXS model mice, in adulthood, also restores the level of mGluR-dependent LTD to that observed in wild-type animals. Translating the findings of successful pharmacologic intervention from the Drosophila model into the mouse model of FXS is an important advance, in that this identifies and validates PDE-4 inhibition as potential therapeutic intervention for the treatment of individuals afflicted with FXS.
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21
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Hoedjes KM, Smid HM, Schijlen EGWM, Vet LEM, van Vugt JJFA. Learning-induced gene expression in the heads of two Nasonia species that differ in long-term memory formation. BMC Genomics 2015; 16:162. [PMID: 25888126 PMCID: PMC4440501 DOI: 10.1186/s12864-015-1355-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 02/18/2015] [Indexed: 12/21/2022] Open
Abstract
Background Cellular processes underlying memory formation are evolutionary conserved, but natural variation in memory dynamics between animal species or populations is common. The genetic basis of this fascinating phenomenon is poorly understood. Closely related species of Nasonia parasitic wasps differ in long-term memory (LTM) formation: N. vitripennis will form transcription-dependent LTM after a single conditioning trial, whereas the closely-related species N. giraulti will not. Genes that were differentially expressed (DE) after conditioning in N. vitripennis, but not in N. giraulti, were identified as candidate genes that may regulate LTM formation. Results RNA was collected from heads of both species before and immediately, 4 or 24 hours after conditioning, with 3 replicates per time point. It was sequenced strand-specifically, which allows distinguishing sense from antisense transcripts and improves the quality of expression analyses. We determined conditioning-induced DE compared to naïve controls for both species. These expression patterns were then analysed with GO enrichment analyses for each species and time point, which demonstrated an enrichment of signalling-related genes immediately after conditioning in N. vitripennis only. Analyses of known LTM genes and genes with an opposing expression pattern between the two species revealed additional candidate genes for the difference in LTM formation. These include genes from various signalling cascades, including several members of the Ras and PI3 kinase signalling pathways, and glutamate receptors. Interestingly, several other known LTM genes were exclusively differentially expressed in N. giraulti, which may indicate an LTM-inhibitory mechanism. Among the DE transcripts were also antisense transcripts. Furthermore, antisense transcripts aligning to a number of known memory genes were detected, which may have a role in regulating these genes. Conclusion This study is the first to describe and compare expression patterns of both protein-coding and antisense transcripts, at different time points after conditioning, of two closely related animal species that differ in LTM formation. Several candidate genes that may regulate differences in LTM have been identified. This transcriptome analysis is a valuable resource for future in-depth studies to elucidate the role of candidate genes and antisense transcription in natural variation in LTM formation. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1355-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katja M Hoedjes
- Laboratory of Entomology, Plant Sciences Group, Wageningen University, P.O. box 8031, 6700AP, Wageningen, The Netherlands. .,Department of Ecology and Evolution, University of Lausanne, Le Biophore, CH-1015, Lausanne, Switzerland.
| | - Hans M Smid
- Laboratory of Entomology, Plant Sciences Group, Wageningen University, P.O. box 8031, 6700AP, Wageningen, The Netherlands.
| | - Elio G W M Schijlen
- PRI Bioscience, Plant Research International, P.O. box 619, 6700AP, Wageningen, The Netherlands.
| | - Louise E M Vet
- Laboratory of Entomology, Plant Sciences Group, Wageningen University, P.O. box 8031, 6700AP, Wageningen, The Netherlands. .,Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB, Wageningen, The Netherlands.
| | - Joke J F A van Vugt
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB, Wageningen, The Netherlands. .,Department of Neurology, University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
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22
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A novel paradigm for nonassociative long-term memory in Drosophila: predator-induced changes in oviposition behavior. Genetics 2015; 199:1143-57. [PMID: 25633088 DOI: 10.1534/genetics.114.172221] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/20/2015] [Indexed: 11/18/2022] Open
Abstract
Learning processes in Drosophila have been studied through the use of Pavlovian associative memory tests, and these paradigms have been extremely useful in identifying both genetic factors and neuroanatomical structures that are essential to memory formation. Whether these same genes and brain compartments also contribute to memory formed from nonassociative experiences is not well understood. Exposures to environmental stressors such as predators are known to induce innate behavioral responses and can lead to new memory formation that allows a predator response to persist for days after the predator threat has been removed. Here, we utilize a unique form of nonassociative behavior in Drosophila where female flies detect the presence of endoparasitoid predatory wasps and alter their oviposition behavior to lay eggs in food containing high levels of alcohol. The predator-induced change in fly oviposition preference is maintained for days after wasps are removed, and this persistence in behavior requires a minimum continuous exposure time of 14 hr. Maintenance of this behavior is dependent on multiple long-term memory genes, including orb2, dunce, rutabaga, amnesiac, and Fmr1. Maintenance of the behavior also requires intact synaptic transmission of the mushroom body. Surprisingly, synaptic output from the mushroom body (MB) or the functions of any of these learning and memory genes are not required for the change in behavior when female flies are in constant contact with wasps. This suggests that perception of this predator that leads to an acute change in oviposition behavior is not dependent on the MB or dependent on learning and memory gene functions. Because wasp-induced oviposition behavior can last for days and its maintenance requires a functional MB and the wild-type products of several known learning and memory genes, we suggest that this constitutes a paradigm for a bona fide form of nonassociative long-term memory that is not dependent on associated experiences.
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Smith R, Rathod RJ, Rajkumar S, Kennedy D. Nervous translation, do you get the message? A review of mRNPs, mRNA-protein interactions and translational control within cells of the nervous system. Cell Mol Life Sci 2014; 71:3917-37. [PMID: 24952431 PMCID: PMC11113408 DOI: 10.1007/s00018-014-1660-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/22/2014] [Accepted: 05/30/2014] [Indexed: 01/01/2023]
Abstract
In neurons, translation of a message RNA can occur metres away from its transcriptional origin and in normal cells this is orchestrated with perfection. The life of an mRNA will see it pass through multiple steps of processing in the nucleus and the cytoplasm before it reaches its final destination. Processing of mRNA is determined by a myriad of RNA-binding proteins in multi-protein complexes called messenger ribonucleoproteins; however, incorrect processing and delivery of mRNA can cause several human neurological disorders. This review takes us through the life of mRNA from the nucleus to its point of translation in the cytoplasm. The review looks at the various cis and trans factors that act on the mRNA and discusses their roles in different cells of the nervous system and human disorders.
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Affiliation(s)
- Ross Smith
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia,
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Thomas MG, Pascual ML, Maschi D, Luchelli L, Boccaccio GL. Synaptic control of local translation: the plot thickens with new characters. Cell Mol Life Sci 2014; 71:2219-39. [PMID: 24212248 PMCID: PMC11113725 DOI: 10.1007/s00018-013-1506-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Revised: 10/11/2013] [Accepted: 10/21/2013] [Indexed: 12/18/2022]
Abstract
The production of proteins from mRNAs localized at the synapse ultimately controls the strength of synaptic transmission, thereby affecting behavior and cognitive functions. The regulated transcription, processing, and transport of mRNAs provide dynamic control of the dendritic transcriptome, which includes thousands of messengers encoding multiple cellular functions. Translation is locally modulated by synaptic activity through a complex network of RNA-binding proteins (RBPs) and various types of non-coding RNAs (ncRNAs) including BC-RNAs, microRNAs, piwi-interacting RNAs, and small interference RNAs. The RBPs FMRP and CPEB play a well-established role in synaptic translation, and additional regulatory factors are emerging. The mRNA repressors Smaug, Nanos, and Pumilio define a novel pathway for local translational control that affects dendritic branching and spines in both flies and mammals. Recent findings support a role for processing bodies and related synaptic mRNA-silencing foci (SyAS-foci) in the modulation of synaptic plasticity and memory formation. The SyAS-foci respond to different stimuli with changes in their integrity thus enabling regulated mRNA release followed by translation. CPEB, Pumilio, TDP-43, and FUS/TLS form multimers through low-complexity regions related to prion domains or polyQ expansions. The oligomerization of these repressor RBPs is mechanistically linked to the aggregation of abnormal proteins commonly associated with neurodegeneration. Here, we summarize the current knowledge on how specificity in mRNA translation is achieved through the concerted action of multiple pathways that involve regulatory ncRNAs and RBPs, the modification of translation factors, and mRNA-silencing foci dynamics.
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Affiliation(s)
- María Gabriela Thomas
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- IIBBA-CONICET, C1405BWE Buenos Aires, Argentina
| | - Malena Lucía Pascual
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- IIBBA-CONICET, C1405BWE Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Buenos Aires, Argentina
| | - Darío Maschi
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- Present Address: Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO USA
| | - Luciana Luchelli
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- IIBBA-CONICET, C1405BWE Buenos Aires, Argentina
| | - Graciela Lidia Boccaccio
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- IIBBA-CONICET, C1405BWE Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Buenos Aires, Argentina
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McBride SMJ, Holloway SL, Jongens TA. Using Drosophila as a tool to identify pharmacological therapies for fragile X syndrome. DRUG DISCOVERY TODAY. TECHNOLOGIES 2014; 10:e129-36. [PMID: 24050241 DOI: 10.1016/j.ddtec.2012.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Despite obvious differences such as the ability to fly, the fruit fly Drosophila melanogaster is similar to humans at many different levels of complexity. Studies of development, cell growth and division, metabolism and even cognition, have borne out these similarities. For example, Drosophila bearing mutations in the fly gene homologue of the known human disease fragile X are affected in fundamentally similar ways as affected humans. The ramification of this degree of similarity is that Drosophila, as a model organism, is a rich resource for learning about human cells, development and even human cognition and behavior. Drosophila has a short generation time of ten days, is cheap to propagate and maintain and has a vast array of genetic tools available to it; making Drosophila an extremely attractive organism for the study of human disease. Here, we summarize research from our lab and others using Drosophila to understand the human neurological disease, called fragile X. We focus on the Drosophila model of fragile X, its characterization, and use as a tool to identify potential drugs for the treatment of fragile X. Several clinical trials are in progress now that were motivated by this research.
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Espinosa Angarica V, Angulo A, Giner A, Losilla G, Ventura S, Sancho J. PrionScan: an online database of predicted prion domains in complete proteomes. BMC Genomics 2014; 15:102. [PMID: 24498877 PMCID: PMC3922584 DOI: 10.1186/1471-2164-15-102] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 02/04/2014] [Indexed: 12/17/2022] Open
Abstract
Background Prions are a particular type of amyloids related to a large variety of important processes in cells, but also responsible for serious diseases in mammals and humans. The number of experimentally characterized prions is still low and corresponds to a handful of examples in microorganisms and mammals. Prion aggregation is mediated by specific protein domains with a remarkable compositional bias towards glutamine/asparagine and against charged residues and prolines. These compositional features have been used to predict new prion proteins in the genomes of different organisms. Despite these efforts, there are only a few available data sources containing prion predictions at a genomic scale. Description Here we present PrionScan, a new database of predicted prion-like domains in complete proteomes. We have previously developed a predictive methodology to identify and score prionogenic stretches in protein sequences. In the present work, we exploit this approach to scan all the protein sequences in public databases and compile a repository containing relevant information of proteins bearing prion-like domains. The database is updated regularly alongside UniprotKB and in its present version contains approximately 28000 predictions in proteins from different functional categories in more than 3200 organisms from all the taxonomic subdivisions. PrionScan can be used in two different ways: database query and analysis of protein sequences submitted by the users. In the first mode, simple queries allow to retrieve a detailed description of the properties of a defined protein. Queries can also be combined to generate more complex and specific searching patterns. In the second mode, users can submit and analyze their own sequences. Conclusions It is expected that this database would provide relevant insights on prion functions and regulation from a genome-wide perspective, allowing researches performing cross-species prion biology studies. Our database might also be useful for guiding experimentalists in the identification of new candidates for further experimental characterization.
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Affiliation(s)
- Vladimir Espinosa Angarica
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain.
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FMRP and Ataxin-2 function together in long-term olfactory habituation and neuronal translational control. Proc Natl Acad Sci U S A 2013; 111:E99-E108. [PMID: 24344294 DOI: 10.1073/pnas.1309543111] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Fragile X mental retardation protein (FMRP) and Ataxin-2 (Atx2) are triplet expansion disease- and stress granule-associated proteins implicated in neuronal translational control and microRNA function. We show that Drosophila FMRP (dFMR1) is required for long-term olfactory habituation (LTH), a phenomenon dependent on Atx2-dependent potentiation of inhibitory transmission from local interneurons (LNs) to projection neurons (PNs) in the antennal lobe. dFMR1 is also required for LTH-associated depression of odor-evoked calcium transients in PNs. Strong transdominant genetic interactions among dFMR1, atx2, the deadbox helicase me31B, and argonaute1 (ago1) mutants, as well as coimmunoprecitation of dFMR1 with Atx2, indicate that dFMR1 and Atx2 function together in a microRNA-dependent process necessary for LTH. Consistently, PN or LN knockdown of dFMR1, Atx2, Me31B, or the miRNA-pathway protein GW182 increases expression of a Ca2+/calmodulin-dependent protein kinase II (CaMKII) translational reporter. Moreover, brain immunoprecipitates of dFMR1 and Atx2 proteins include CaMKII mRNA, indicating respective physical interactions with this mRNA. Because CaMKII is necessary for LTH, these data indicate that fragile X mental retardation protein and Atx2 act via at least one common target RNA for memory-associated long-term synaptic plasticity. The observed requirement in LNs and PNs supports an emerging view that both presynaptic and postsynaptic translation are necessary for long-term synaptic plasticity. However, whereas Atx2 is necessary for the integrity of dendritic and somatic Me31B-containing particles, dFmr1 is not. Together, these data indicate that dFmr1 and Atx2 function in long-term but not short-term memory, regulating translation of at least some common presynaptic and postsynaptic target mRNAs in the same cells.
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Schoenfeld BP, Choi RJ, Choi CH, Terlizzi AM, Hinchey P, Kollaros M, Ferrick NJ, Koenigsberg E, Ferreiro D, Leibelt DA, Siegel SJ, Bell AJ, McDonald TV, Jongens TA, McBride SMJ. The Drosophila DmGluRA is required for social interaction and memory. Front Pharmacol 2013; 4:64. [PMID: 23720628 PMCID: PMC3662090 DOI: 10.3389/fphar.2013.00064] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 04/26/2013] [Indexed: 11/13/2022] Open
Abstract
Metabotropic glutamate receptors (mGluRs) have well-established roles in cognition and social behavior in mammals. Whether or not these roles have been conserved throughout evolution from invertebrate species is less clear. Mammals have eight mGluRs whereas Drosophila has a single DmGluRA, which has both Gi and Gq coupled signaling activity. We have utilized Drosophila to examine the role of DmGluRA in social behavior and various phases of memory. We have found that flies that are homozygous or heterozygous for loss of function mutations of DmGluRA have impaired social behavior in male Drosophila. Futhermore, flies that are heterozygous for loss of function mutations of DmGluRA have impaired learning during training, immediate-recall memory, short-term memory, and long-term memory as young adults. This work demonstrates a role for mGluR activity in both social behavior and memory in Drosophila.
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Affiliation(s)
- Brian P Schoenfeld
- Section of Molecular Cardiology, Department of Molecular Pharmacology and Medicine, Albert Einstein College of Medicine Bronx, NY, USA ; Department of Genetics, University of Pennsylvania School of Medicine Philadelphia, PA, USA
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Espinosa Angarica V, Ventura S, Sancho J. Discovering putative prion sequences in complete proteomes using probabilistic representations of Q/N-rich domains. BMC Genomics 2013; 14:316. [PMID: 23663289 PMCID: PMC3654983 DOI: 10.1186/1471-2164-14-316] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 05/06/2013] [Indexed: 01/23/2023] Open
Abstract
Background Prion proteins conform a special class among amyloids due to their ability to transmit aggregative folds. Prions are known to act as infectious agents in neurodegenerative diseases in animals, or as key elements in transcription and translation processes in yeast. It has been suggested that prions contain specific sequential domains with distinctive amino acid composition and physicochemical properties that allow them to control the switch between soluble and β-sheet aggregated states. Those prion-forming domains are low complexity segments enriched in glutamine/asparagine and depleted in charged residues and prolines. Different predictive methods have been developed to discover novel prions by either assessing the compositional bias of these stretches or estimating the propensity of protein sequences to form amyloid aggregates. However, the available algorithms hitherto lack a thorough statistical calibration against large sequence databases, which makes them unable to accurately predict prions without retrieving a large number of false positives. Results Here we present a computational strategy to predict putative prion-forming proteins in complete proteomes using probabilistic representations of prionogenic glutamine/asparagine rich regions. After benchmarking our predictive model against large sets of non-prionic sequences, we were able to filter out known prions with high precision and accuracy, generating prediction sets with few false positives. The algorithm was used to scan all the proteomes annotated in public databases for the presence of putative prion proteins. We analyzed the presence of putative prion proteins in all taxa, from viruses and archaea to plants and higher eukaryotes, and found that most organisms encode evolutionarily unrelated proteins with susceptibility to behave as prions. Conclusions To our knowledge, this is the first wide-ranging study aiming to predict prion domains in complete proteomes. Approaches of this kind could be of great importance to identify potential targets for further experimental testing and to try to reach a deeper understanding of prions’ functional and regulatory mechanisms.
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Affiliation(s)
- Vladimir Espinosa Angarica
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna 12, Zaragoza 50009, Spain
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van Alphen B, van Swinderen B. Drosophila strategies to study psychiatric disorders. Brain Res Bull 2013; 92:1-11. [DOI: 10.1016/j.brainresbull.2011.09.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 09/08/2011] [Accepted: 09/09/2011] [Indexed: 01/03/2023]
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Gareau C, Houssin E, Martel D, Coudert L, Mellaoui S, Huot ME, Laprise P, Mazroui R. Characterization of fragile X mental retardation protein recruitment and dynamics in Drosophila stress granules. PLoS One 2013; 8:e55342. [PMID: 23408971 PMCID: PMC3567066 DOI: 10.1371/journal.pone.0055342] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 12/21/2012] [Indexed: 01/27/2023] Open
Abstract
The RNA-binding protein Fragile X Mental Retardation (FMRP) is an evolutionarily conserved protein that is particularly abundant in the brain due to its high expression in neurons. FMRP deficiency causes fragile X mental retardation syndrome. In neurons, FMRP controls the translation of target mRNAs in part by promoting dynamic transport in and out neuronal RNA granules. We and others have previously shown that upon stress, mammalian FMRP dissociates from translating polysomes to localize into neuronal-like granules termed stress granules (SG). This localization of FMRP in SG is conserved in Drosophila. Whether FMRP plays a key role in SG formation, how FMRP is recruited into SG, and whether its association with SG is dynamic are currently unknown. In contrast with mammalian FMRP, which has two paralog proteins, Drosophila FMR1 (dFMRP) is encoded by a single gene that has no paralog. Using this genetically simple model, we assessed the role of dFMRP in SG formation and defined the determinants required for its recruitment in SG as well as its dynamics in SG. We show that dFMRP is dispensable for SG formation in vitro and ex vivo. FRAP experiments showed that dFMRP shuttles in and out SG. The shuttling activity of dFMRP is mediated by a protein-protein interaction domain located at the N-terminus of the protein. This domain is, however, dispensable for the localization of dFMRP in SG. This localization of dFMRP in SG requires the KH and RGG motifs which are known to mediate RNA binding, as well as the C-terminal glutamine/asparagine rich domain. Our studies thus suggest that the mechanisms controlling the recruitment of FMRP into SG and those that promote its shuttling between granules and the cytosol are uncoupled. To our knowledge, this is the first demonstration of the regulated shuttling activity of a SG component between RNA granules and the cytosol.
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Affiliation(s)
- Cristina Gareau
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Faculty of Medicine, Laval University, Centre de recherche le CHU de Quebec, Quebec, Canada
| | - Elise Houssin
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Faculty of Medicine, Laval University, Centre de recherche le CHU de Quebec, Quebec, Canada
| | - David Martel
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Faculty of Medicine, Laval University, Centre de recherche le CHU de Quebec, Quebec, Canada
| | - Laetitia Coudert
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Faculty of Medicine, Laval University, Centre de recherche le CHU de Quebec, Quebec, Canada
| | - Samia Mellaoui
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Faculty of Medicine, Laval University, Centre de recherche le CHU de Quebec, Quebec, Canada
| | - Marc-Etienne Huot
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Faculty of Medicine, Laval University, Centre de recherche le CHU de Quebec, Quebec, Canada
| | - Patrick Laprise
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Faculty of Medicine, Laval University, Centre de recherche le CHU de Quebec, Quebec, Canada
| | - Rachid Mazroui
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Faculty of Medicine, Laval University, Centre de recherche le CHU de Quebec, Quebec, Canada
- * E-mail:
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Learning and memory deficits consequent to reduction of the fragile X mental retardation protein result from metabotropic glutamate receptor-mediated inhibition of cAMP signaling in Drosophila. J Neurosci 2012; 32:13111-24. [PMID: 22993428 DOI: 10.1523/jneurosci.1347-12.2012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Loss of the RNA-binding fragile X protein [fragile X mental retardation protein (FMRP)] results in a spectrum of cognitive deficits, the fragile X syndrome (FXS), while aging individuals with decreased protein levels present with a subset of these symptoms and tremor. The broad range of behavioral deficits likely reflects the ubiquitous distribution and multiple functions of the protein. FMRP loss is expected to affect multiple neuronal proteins and intracellular signaling pathways, whose identity and interactions are essential in understanding and ameliorating FXS symptoms. We used heterozygous mutants and targeted RNA interference-mediated abrogation in Drosophila to uncover molecular pathways affected by FMRP reduction. We present evidence that FMRP loss results in excess metabotropic glutamate receptor (mGluR) activity, attributable at least in part to elevation of the protein in affected neurons. Using high-resolution behavioral, genetic, and biochemical analyses, we present evidence that excess mGluR upon FMRP attenuation is linked to the cAMP decrement reported in patients and models, and underlies olfactory associative learning and memory deficits. Furthermore, our data indicate positive transcriptional regulation of the fly fmr1 gene by cAMP, via protein kinase A, likely through the transcription factor CREB. Because the human Fmr1 gene also contains CREB binding sites, the interaction of mGluR excess and cAMP signaling defects we present suggests novel combinatorial pharmaceutical approaches to symptom amelioration upon FMRP attenuation.
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Identification of gene expression changes associated with long-term memory of courtship rejection in Drosophila males. G3-GENES GENOMES GENETICS 2012; 2:1437-45. [PMID: 23173095 PMCID: PMC3484674 DOI: 10.1534/g3.112.004119] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 09/16/2012] [Indexed: 11/18/2022]
Abstract
Long-term memory formation in Drosophila melanogaster is an important neuronal function shaping the insect’s behavioral repertoire by allowing an individual to modify behaviors on the basis of previous experiences. In conditioned courtship or courtship suppression, male flies that have been repeatedly rejected by mated females during courtship advances are less likely than naïve males to subsequently court another mated female. This long-term courtship suppression can last for several days after the initial rejection period. Although genes with known functions in many associative learning paradigms, including those that function in cyclic AMP signaling and RNA translocation, have been identified as playing critical roles in long-term conditioned courtship, it is clear that additional mechanisms also contribute. We have used RNA sequencing to identify differentially expressed genes and transcript isoforms between naïve males and males subjected to courtship-conditioning regimens that are sufficient for inducing long-term courtship suppression. Transcriptome analyses 24 hours after the training regimens revealed differentially expressed genes and transcript isoforms with predicted and known functions in nervous system development, chromatin biology, translation, cytoskeletal dynamics, and transcriptional regulation. A much larger number of differentially expressed transcript isoforms were identified, including genes previously implicated in associative memory and neuronal development, including fruitless, that may play functional roles in learning during courtship conditioning. Our results shed light on the complexity of the genetics that underlies this behavioral plasticity and reveal several new potential areas of inquiry for future studies.
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Pascual ML, Luchelli L, Habif M, Boccaccio GL. Synaptic activity regulated mRNA-silencing foci for the fine tuning of local protein synthesis at the synapse. Commun Integr Biol 2012; 5:388-92. [PMID: 23060966 PMCID: PMC3460847 DOI: 10.4161/cib.20257] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The regulated synthesis of specific proteins at the synapse is important for neuron plasticity, and several localized mRNAs are translated upon specific stimulus. Repression of mRNA translation is linked to the formation of mRNA-silencing foci, including Processing Bodies (PBs) and Stress Granules (SGs), which are macromolecular aggregates that harbor silenced messengers and associated proteins. In a recent work, we identified a kind of mRNA-silencing foci unique to neurons, termed S-foci, that contain the post-transcriptional regulator Smaug1/SAMD4. Upon specific synaptic stimulation, the S-foci dissolve and release mRNAs to allow their translation, paralleling the cycling of mRNAs between PBs and polysomes in other cellular contexts. Smaug 1 and other proteins involved in mRNA regulation in neurons contain aggregation domains distinct from their RNA binding motifs, and we speculate that self-aggregation helps silencing and transport. In addition to S-foci and PBs, other foci formed by distinct RNA binding proteins, such as TDP-43 and FMRP among others, respond dynamically to specific synaptic stimuli. We propose the collective name of synaptic activity-regulated mRNA silencing (SyAS) foci for these RNP aggregates that selectively respond to distinct stimulation patterns and contribute to the fine-tuning of local protein synthesis at the synapse.
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Affiliation(s)
- Malena Lucia Pascual
- Instituto Leloir; IIBBA-CONICET and Facultad de Ciencias Exactas y Naturales; University of Buenos Aires; Buenos Aires, Argentina
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Okray Z, Hassan BA. Genetic approaches in Drosophila for the study neurodevelopmental disorders. Neuropharmacology 2012; 68:150-6. [PMID: 23067575 DOI: 10.1016/j.neuropharm.2012.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 08/31/2012] [Accepted: 09/07/2012] [Indexed: 12/16/2022]
Abstract
The fruit fly Drosophila melanogaster is one of the premier genetic model organisms used in biomedical research today owing to the extraordinary power of its genetic tool-kit. Made famous by numerous seminal discoveries of basic developmental mechanisms and behavioral genetics, the power of fruit fly genetics is becoming increasingly applied to questions directly relevant to human health. In this review we discuss how Drosophila research is applied to address major questions in neurodevelopmental disorders. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
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Affiliation(s)
- Zeynep Okray
- Laboratory of Neurogenetics, VIB Center for the Biology of Disease, VIB, Herestraat 49, Leuven, Belgium
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Trivedi MS, Deth RC. Role of a redox-based methylation switch in mRNA life cycle (pre- and post-transcriptional maturation) and protein turnover: implications in neurological disorders. Front Neurosci 2012; 6:92. [PMID: 22740813 PMCID: PMC3382963 DOI: 10.3389/fnins.2012.00092] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 06/06/2012] [Indexed: 12/31/2022] Open
Abstract
Homeostatic synaptic scaling in response to neuronal stimulus or activation, and due to changes in cellular niche, is an important phenomenon for memory consolidation, retrieval, and other similar cognitive functions (Turrigiano and Nelson, 2004). Neurological disorders and cognitive disabilities in autism, Rett syndrome, schizophrenia, dementia, etc., are strongly correlated to alterations in protein expression (both synaptic and cytoplasmic; Cajigas et al., 2010). This correlation suggests that efficient temporal regulation of synaptic protein expression is important for synaptic plasticity. In addition, equilibrium between mRNA processing, protein translation, and protein turnover is a critical sensor/trigger for recording synaptic information, normal cognition, and behavior (Cajigas et al., 2010). Thus a regulatory switch, which controls the lifespan, maturation, and processing of mRNA, might influence cognition and adaptive behavior. Here, we propose a two part novel hypothesis that methylation might act as this suggested coordinating switch to critically regulate mRNA maturation at (1) the pre-transcription level, by regulating precursor-RNA processing into mRNA, via other non-coding RNAs and their influence on splicing phenomenon, and (2) the post-transcription level by modulating the regulatory functions of ribonucleoproteins and RNA binding proteins in mRNA translation, dendritic translocation as well as protein synthesis and synaptic turnover. DNA methylation changes are well recognized and highly correlated to gene expression levels as well as, learning and memory; however, RNA methylation changes are recently characterized and yet their functional implications are not established. This review article provides some insight on the intriguing consequences of changes in methylation levels on mRNA life-cycle. We also suggest that, since methylation is under the control of glutathione anti-oxidant levels (Lertratanangkoon et al., 1997), the redox status of neurons might be the central regulatory switch for methylation-based changes in mRNA processing, protein expression, and turnover. Lastly, we also describe experimental methods and techniques which might help researchers to evaluate the suggested hypothesis.
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Affiliation(s)
- Malav S Trivedi
- Department of Pharmaceutical Sciences, Northeastern University Boston, MA, USA
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Rushton E, Rohrbough J, Deutsch K, Broadie K. Structure-function analysis of endogenous lectin mind-the-gap in synaptogenesis. Dev Neurobiol 2012; 72:1161-79. [PMID: 22234957 DOI: 10.1002/dneu.22006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/20/2011] [Accepted: 12/29/2011] [Indexed: 01/07/2023]
Abstract
Mind-the-Gap (MTG) is required for neuronal induction of Drosophila neuromuscular junction (NMJ) postsynaptic domains, including glutamate receptor (GluR) localization. We have previously hypothesized that MTG is secreted from the presynaptic terminal to reside in the synaptic cleft, where it binds glycans to organize the heavily glycosylated, extracellular synaptomatrix required for transsynaptic signaling between neuron and muscle. In this study, we test this hypothesis with MTG structure-function analyses of predicted signal peptide (SP) and carbohydrate-binding domain (CBD), by introducing deletion and point-mutant transgenic constructs into mtg null mutants. We show that the SP is required for MTG secretion and localization to synapses in vivo. We further show that the CBD is required to restrict MTG diffusion in the extracellular synaptomatrix and for postembryonic viability. However, CBD mutation results in elevation of postsynaptic GluR localization during synaptogenesis, not the mtg null mutant phenotype of reduced GluRs as predicted by our hypothesis, suggesting that proper synaptic localization of MTG limits GluR recruitment. In further testing CBD requirements, we show that MTG binds N-acetylglucosamine (GlcNAc) in a Ca(2+)-dependent manner, and thereby binds HRP-epitope glycans, but that these carbohydrate interactions do not require the CBD. We conclude that the MTG lectin has both positive and negative binding interactions with glycans in the extracellular synaptic domain, which both facilitate and limit GluR localization during NMJ embryonic synaptogenesis.
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Affiliation(s)
- Emma Rushton
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA
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Abstract
This chapter will briefly tie together a captivating string of scientific discoveries that began in the 1800s and catapulted us into the current state of the field where trials are under way in humans that have arisen directly from the discoveries made in model organisms such as Drosophila (fruit flies) and mice. The hope is that research efforts in the field of fragile X currently represent a roadmap that demonstrates the utility of identifying a mutant gene responsible for human disease, tracking down the molecular underpinnings of pathogenic phenotypes, and utilizing model organisms to identify and validate potential pharmacologic targets for testing in afflicted humans. Indeed, in fragile X this roadmap has already yielded successful trials in humans (J. Med. Genetic 46(4) 266-271; Jacquemont et al. Sci Transl Med 3(64):64ra61), although the work in studying these interventions in humans is just getting underway as the work in model organisms continues to generate new potential therapeutic targets.
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McLennan Y, Polussa J, Tassone F, Hagerman R. Fragile x syndrome. Curr Genomics 2011; 12:216-24. [PMID: 22043169 PMCID: PMC3137006 DOI: 10.2174/138920211795677886] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 03/30/2011] [Accepted: 03/31/2011] [Indexed: 02/03/2023] Open
Abstract
Recent data from a national survey highlighted a significant difference in obesity rates in young fragile X males (31%) compared to age matched controls (18%). Fragile X syndrome (FXS) is the most common cause of intellectual disability in males and the most common single gene cause of autism. This X-linked disorder is caused by an expansion of a trinucleotide CGG repeat (>200) on the promotor region of the fragile X mental retardation 1 gene (FMR1). As a result, the promotor region often becomes methylated which leads to a deficiency or absence of the FMR1 protein (FMRP). Common characteristics of FXS include mild to severe cognitive impairments in males but less severe cognitive impairment in females. Physical features of FXS include an elongated face, prominent ears, and post-pubertal macroorchidism. Severe obesity in full mutation males is often associated with the Prader-Willi phenotype (PWP) which includes hyperphagia, lack of satiation after meals, and hypogonadism or delayed puberty; however, there is no deletion at 15q11-q13 nor uniparental maternal disomy. Herein, we discuss the molecular mechanisms leading to FXS and the Prader-Willi phenotype with an emphasis on mouse FMR1 knockout studies that have shown the reversal of weight increase through mGluR antagonists. Finally, we review the current medications used in treatment of FXS including the atypical antipsychotics that can lead to weight gain and the research regarding the use of targeted treatments in FXS that will hopefully have a significantly beneficial effect on cognition and behavior without weight gain.
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Affiliation(s)
- Yingratana McLennan
- Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California Davis Health System, Sacramento, California, USA
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Berger-Sweeney J. Cognitive deficits in Rett syndrome: What we know and what we need to know to treat them. Neurobiol Learn Mem 2011; 96:637-46. [DOI: 10.1016/j.nlm.2011.05.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 05/04/2011] [Accepted: 05/13/2011] [Indexed: 10/18/2022]
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Santoro MR, Bray SM, Warren ST. Molecular mechanisms of fragile X syndrome: a twenty-year perspective. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2011; 7:219-45. [PMID: 22017584 DOI: 10.1146/annurev-pathol-011811-132457] [Citation(s) in RCA: 377] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Fragile X syndrome (FXS) is a common form of inherited intellectual disability and is one of the leading known causes of autism. The mutation responsible for FXS is a large expansion of the trinucleotide CGG repeat in the 5' untranslated region of the X-linked gene FMR1. This expansion leads to DNA methylation of FMR1 and to transcriptional silencing, which results in the absence of the gene product, FMRP, a selective messenger RNA (mRNA)-binding protein that regulates the translation of a subset of dendritic mRNAs. FMRP is critical for mGluR (metabotropic glutamate receptor)-dependent long-term depression, as well as for other forms of synaptic plasticity; its absence causes excessive and persistent protein synthesis in postsynaptic dendrites and dysregulated synaptic function. Studies continue to refine our understanding of FMRP's role in synaptic plasticity and to uncover new functions of this protein, which have illuminated therapeutic approaches for FXS.
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Affiliation(s)
- Michael R Santoro
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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Abstract
Epigenomic settings control gene regulation in both developing and postmitotic tissue, whereas abnormal regulation of epigenomic settings has been implicated in many developmental and neurological disorders. Evidence is emerging for the roles of epigenetic mechanisms in the mature nervous system, in the dynamic processes of learning and memory. The discovery of the involvement of DNA methylation and histone acetylation and methylation in neuronal processing provides a possible answer to the long-standing riddle of how memories persist in a biological system whose cellular composition is in a constant state of flux and renewal. This mini review focuses on present research in DNA methylation and histone posttranslational modifications in learning and memory, age-related cognitive decline, and related pathological disorders.
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Gatto CL, Broadie K. Drosophila modeling of heritable neurodevelopmental disorders. Curr Opin Neurobiol 2011; 21:834-41. [PMID: 21596554 DOI: 10.1016/j.conb.2011.04.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 04/08/2011] [Accepted: 04/25/2011] [Indexed: 11/16/2022]
Abstract
Heritable neurodevelopmental disorders are multifaceted disease conditions encompassing a wide range of symptoms including intellectual disability, cognitive dysfunction, autism and myriad other behavioral impairments. In cases where single, causative genetic defects have been identified, such as Angelman syndrome, Rett syndrome, Neurofibromatosis Type 1 and Fragile X syndrome, the classical Drosophila genetic system has provided fruitful disease models. Recent Drosophila studies have advanced our understanding of UBE3A, MECP2, NF1 and FMR1 function, respectively, in genetic, biochemical, anatomical, physiological and behavioral contexts. Investigations in Drosophila continue to provide the essential mechanistic understanding required to facilitate the conception of rational therapeutic treatments.
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Affiliation(s)
- Cheryl L Gatto
- Departments of Biological Sciences and Cell and Developmental Biology, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA
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Beerman RW, Jongens TA. A non-canonical start codon in the Drosophila fragile X gene yields two functional isoforms. Neuroscience 2011; 181:48-66. [PMID: 21333716 DOI: 10.1016/j.neuroscience.2011.02.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 02/10/2011] [Accepted: 02/12/2011] [Indexed: 02/07/2023]
Abstract
Fragile X syndrome is caused by the loss of expression of the fragile X mental retardation protein (FMRP). As a RNA binding protein, FMRP functions in translational regulation, localization, and stability of its neuronal target transcripts. The Drosophila homologue, dFMR1, is well conserved in sequence and function with respect to human FMRP. Although dFMR1 is known to express two main isoforms, the mechanism behind production of the second, more slowly migrating isoform has remained elusive. Furthermore, it remains unknown whether the two isoforms may also contribute differentially to dFMR1 function. We have found that this second dFMR1 isoform is generated through an alternative translational start site in the dfmr1 5'UTR. This 5'UTR coding sequence is well conserved in the melanogaster group. Translation of the predominant, smaller form of dFMR1 (dFMR1-S(N)) begins at a canonical start codon (ATG), whereas translation of the minor, larger form (dFMR1-L(N)) begins upstream at a non-canonical start codon (CTG). To assess the contribution of the N-terminal extension toward dFMR1 activity, we generated transgenic flies that exclusively express either dFMR1-S(N) or dFMR1-L(N). Expression analyses throughout development revealed that dFMR1-S(N) is required for normal dFMR1-L(N) expression levels in adult brains. In situ expression analyses showed that either dFMR1-S(N) or dFMR1-L(N) is individually sufficient for proper dFMR1 localization in the nervous system. Functional studies demonstrated that both dFMR1-S(N) and dFMR1-L(N) can function independently to rescue dfmr1 null defects in synaptogenesis and axon guidance. Thus, dfmr1 encodes two functional isoforms with respect to expression and activity throughout neuronal development.
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Affiliation(s)
- R W Beerman
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Thomas MG, Loschi M, Desbats MA, Boccaccio GL. RNA granules: the good, the bad and the ugly. Cell Signal 2011; 23:324-34. [PMID: 20813183 PMCID: PMC3001194 DOI: 10.1016/j.cellsig.2010.08.011] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 08/20/2010] [Indexed: 12/13/2022]
Abstract
Processing bodies (PBs) and Stress Granules (SGs) are the founding members of a new class of RNA granules, known as mRNA silencing foci, as they harbour transcripts circumstantially excluded from the translationally active pool. PBs and SGs are able to release mRNAs thus allowing their translation. PBs are constitutive, but respond to stimuli that affect mRNA translation and decay, whereas SGs are specifically induced upon cellular stress, which triggers a global translational silencing by several pathways, including phosphorylation of the key translation initiation factor eIF2alpha, and tRNA cleavage among others. PBs and SGs with different compositions may coexist in a single cell. These macromolecular aggregates are highly conserved through evolution, from unicellular organisms to vertebrate neurons. Their dynamics is regulated by several signaling pathways, and depends on microfilaments and microtubules, and the cognate molecular motors myosin, dynein, and kinesin. SGs share features with aggresomes and related aggregates of unfolded proteins frequently present in neurodegenerative diseases, and may play a role in the pathology. Virus infections may induce or impair SG formation. Besides being important for mRNA regulation upon stress, SGs modulate the signaling balancing apoptosis and cell survival. Finally, the formation of Nuclear Stress Bodies (nSBs), which share components with SGs, and the assembly of additional cytosolic aggregates containing RNA -the UV granules and the Ire1 foci-, all of them induced by specific cell damage factors, contribute to cell survival.
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Key Words
- atxn2, ataxin-2
- bicd, bicaudal d
- cbp, creb binding protein
- cpeb, cytoplasmic polyadenylation element binding protein
- dhc, dynein heavy chain
- dic, dynein intermediate chain
- fak, focal adhesion kinase
- fus/tls/hnrnp p2, fused in sarcoma
- g3bp, ras-gap sh3 domain binding protein
- gcn2, general control nonderepressible-2
- grb7, growth factor receptor-bound protein 7
- hap, hnrnp a1 interacting protein
- hdac6, histone deacetylase 6
- hri, heme-regulated inhibitor
- hsf, heat shock transcription factor
- khc, kinesin heavy chain
- klc, kinesin light chain
- mln51, metastatic lymph node 51
- nmd, nonsense mediated decay
- nsbs, nuclear stress bodies
- ogfod1, 2–14 oxoglutarate and fe(ii)-dependent oxygenase domain containing 1
- pb, processing body
- perk, pancreatic endoplasmic reticulum eif2alpha kinase
- pkr/eif2ak2, double stranded rna-dependent protein kinase
- pp1, protein phosphatase 1
- prp, prion protein
- rbp, rna binding protein
- rnp, ribonucleoparticle
- sam68, src associated in mitosis 68 kda
- member of star, signal transducer and activator of rna
- sca, spinocerebellar ataxia
- sg, stress granule
- sma, spinal muscular atrophy
- fmrp, fragile x mental retardation protein
- smn, survival of motor neuron
- tdp43, tar dna-binding protein 43
- traf2, tnf receptor associated factor 2
- uvgs, uv rna granules
- processing body
- stress granule
- kinesin
- dynein
- bicaudal d
- aggresome
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Affiliation(s)
- María Gabriela Thomas
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
| | - Mariela Loschi
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
| | - María Andrea Desbats
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
| | - Graciela Lidia Boccaccio
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
- University of Buenos Aires
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