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Kuramoto T. Positional cloning of rat mutant genes reveals new functions of these genes. Exp Anim 2023; 72:1-8. [PMID: 36058846 PMCID: PMC9978133 DOI: 10.1538/expanim.22-0089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The laboratory rat (Rattus norvegicus) is a key model organism for biomedical research. Rats can be subjected to strict genetic and environmental controls. The rat's large body size is suitable for both surgical operations and repeated measurements of physiological parameters. These advantages have led to the development of numerous rat models for genetic diseases. Forward genetics is a proven approach for identifying the causative genes of these disease models but requires genome resources including genetic markers and genome sequences. Over the last few decades, rat genome resources have been developed and deposited in bioresource centers, which have enabled us to perform positional cloning in rats. To date, more than 100 disease-related genes have been identified by positional cloning. Since some disease models are more accessible in rats than mice, the identification of causative genes in these models has sometimes led to the discovery of novel functions of genes. As before, various mutant rats are also expected to be discovered and developed as disease models in the future. Thus, the forward genetics continues to be an important approach to find genes involved in disease phenotypes in rats. In this review, I provide an overview the development of rat genome resources and describe examples of positional cloning in rats in which novel gene functions have been identified.
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Affiliation(s)
- Takashi Kuramoto
- Laboratory of Animal Nutrition, Department of Animal Science, Faculty of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa 243-0034, Japan
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2
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Li N, Gao S, Wang S, He S, Wang J, He L, Jiang D, Shi YS, Zhang J, Gu Y, Chen T, Kong M, Xu X, Zhao Q. Attractin Participates in Schizophrenia by Affecting Testosterone Levels. Front Cell Dev Biol 2021; 9:755165. [PMID: 34869343 PMCID: PMC8636034 DOI: 10.3389/fcell.2021.755165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 09/30/2021] [Indexed: 11/30/2022] Open
Abstract
Attractin (ATRN) is a widely expressed glycoprotein that is involved in energy homeostasis, neurodevelopment, and immune response. It is encoded by a gene spanning 180 kb on chromosome 20p13, a region previously implicated in schizophrenia by linkage studies. To address a possible role of ATRN in disorders of the central nervous system, we created an atrn knockout zebrafish line and performed behavioral tests. Adult atrn–/– zebrafish exhibited more pronounced attack behavior relative to wild-type control zebrafish in a tracking analysis. Biochemical analysis revealed elevated testosterone levels in atrn–/– zebrafish. At the gene expression level, we noted an upregulation of cyp51 and hsd17b7, key proteins in testosterone synthesis in the brains of both adult and larvae of atrn–/– zebrafish. In order to further elucidate the relationship between testosterone and behavioral syndromes, we then compared testosterone levels of 9,008 psychiatric patients and 247 healthy controls from the same catchment area. Of all subjects examined, male subjects with schizophrenia exhibited lower testosterone levels compared with controls. In contrast, female subjects with a diagnosis of schizophrenia or bipolar disorder featured higher testosterone levels than did same sex controls. Purposeful sampling of extreme groups showed reduced ATRN expression in a subset of these subjects. Finally, we identified 14 subjects with ATRN mutations. All of whom displayed abnormal testosterone levels. In summary, the interplay of ATRN and testosterone may help to explain sexual dimorphisms in selected behavioral phenotypes.
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Affiliation(s)
- Nan Li
- Model Animal Research Center, Medical School, Nanjing University, Nanjing, China
| | - Shuzhan Gao
- Department of Psychiatry, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Shuang Wang
- Model Animal Research Center, Medical School, Nanjing University, Nanjing, China
| | | | - Jiayin Wang
- Department of Psychiatry, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Luqingqing He
- Model Animal Research Center, Medical School, Nanjing University, Nanjing, China
| | - Dongya Jiang
- Model Animal Research Center, Medical School, Nanjing University, Nanjing, China
| | - Yun Stone Shi
- Department of Psychiatry, Nanjing Brain Hospital, Medical School, Nanjing University, Nanjing, China
| | | | - Yuan Gu
- Department of Psychiatry, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Tian Chen
- Department of Psychiatry, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Mingjun Kong
- Department of Psychiatry, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Xijia Xu
- Department of Psychiatry, Nanjing Brain Hospital, Medical School, Nanjing University, Nanjing, China.,Department of Psychiatry, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Qingshun Zhao
- Model Animal Research Center, Medical School, Nanjing University, Nanjing, China
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3
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Szpirer C. Rat models of human diseases and related phenotypes: a systematic inventory of the causative genes. J Biomed Sci 2020; 27:84. [PMID: 32741357 PMCID: PMC7395987 DOI: 10.1186/s12929-020-00673-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
The laboratory rat has been used for a long time as the model of choice in several biomedical disciplines. Numerous inbred strains have been isolated, displaying a wide range of phenotypes and providing many models of human traits and diseases. Rat genome mapping and genomics was considerably developed in the last decades. The availability of these resources has stimulated numerous studies aimed at discovering causal disease genes by positional identification. Numerous rat genes have now been identified that underlie monogenic or complex diseases and remarkably, these results have been translated to the human in a significant proportion of cases, leading to the identification of novel human disease susceptibility genes, helping in studying the mechanisms underlying the pathological abnormalities and also suggesting new therapeutic approaches. In addition, reverse genetic tools have been developed. Several genome-editing methods were introduced to generate targeted mutations in genes the function of which could be clarified in this manner [generally these are knockout mutations]. Furthermore, even when the human gene causing a disease had been identified without resorting to a rat model, mutated rat strains (in particular KO strains) were created to analyze the gene function and the disease pathogenesis. Today, over 350 rat genes have been identified as underlying diseases or playing a key role in critical biological processes that are altered in diseases, thereby providing a rich resource of disease models. This article is an update of the progress made in this research and provides the reader with an inventory of these disease genes, a significant number of which have similar effects in rat and humans.
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Affiliation(s)
- Claude Szpirer
- Université Libre de Bruxelles, B-6041, Gosselies, Belgium.
- , Waterloo, Belgium.
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Azouz A, Duke-Cohan JS. Post-developmental extracellular proteoglycan maintenance in attractin-deficient mice. BMC Res Notes 2020; 13:301. [PMID: 32580758 PMCID: PMC7313179 DOI: 10.1186/s13104-020-05130-1] [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: 04/03/2020] [Accepted: 06/04/2020] [Indexed: 11/19/2022] Open
Abstract
Objective Neurodegeneration and hair pigmentation alterations in mice occur consequent to aberrations at the Atrn locus coding for the transmembrane form of attractin. Earlier results pointed to a possible involvement in intracellular trafficking/export of secretory vesicles containing proteoglycan. Here we examined kidney and liver, both heavily dependent upon proteoglycan, of attractin-deficient mice to determine whether abnormalities were observed in these tissues. Results Histological and histochemical analysis to detect glycosylated protein identified a severe loss in attractin-deficient mice of extracellular proteoglycan between kidney tubules in addition to a loss of glycosylated material within the intratubular brush border. In the liver, extracellular matrix material was significantly depleted between hepatocytes together with swollen sinuses and aberrations in the proteoglycan-dependent space of Disse. These results are consistent with a generalized defect in extracellular proteoglycan deposition in Atrn-mutant mice and support previous reports suggesting a role for attractin in the secretory vesicle pathway.
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Affiliation(s)
- Abdallah Azouz
- Department of Pathology, Regional One Health, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Jonathan S Duke-Cohan
- Department of Medical Oncology, Dana-Farber Cancer Institute, JF517, 450 Brookline Avenue, Boston, MA, 02215, USA. .,Department of Medicine, Harvard Medical School, Boston, MA, USA.
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5
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Ayhan F, Perez BA, Shorrock HK, Zu T, Banez-Coronel M, Reid T, Furuya H, Clark HB, Troncoso JC, Ross CA, Subramony SH, Ashizawa T, Wang ET, Yachnis AT, Ranum LP. SCA8 RAN polySer protein preferentially accumulates in white matter regions and is regulated by eIF3F. EMBO J 2018; 37:embj.201899023. [PMID: 30206144 DOI: 10.15252/embj.201899023] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 12/12/2022] Open
Abstract
Spinocerebellar ataxia type 8 (SCA8) is caused by a bidirectionally transcribed CTG·CAG expansion that results in the in vivo accumulation of CUG RNA foci, an ATG-initiated polyGln and a polyAla protein expressed by repeat-associated non-ATG (RAN) translation. Although RAN proteins have been reported in a growing number of diseases, the mechanisms and role of RAN translation in disease are poorly understood. We report a novel toxic SCA8 polySer protein which accumulates in white matter (WM) regions as aggregates that increase with age and disease severity. WM regions with polySer aggregates show demyelination and axonal degeneration in SCA8 human and mouse brains. Additionally, knockdown of the eukaryotic translation initiation factor eIF3F in cells reduces steady-state levels of SCA8 polySer and other RAN proteins. Taken together, these data show polySer and WM abnormalities contribute to SCA8 and identify eIF3F as a novel modulator of RAN protein accumulation.
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Affiliation(s)
- Fatma Ayhan
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Barbara A Perez
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hannah K Shorrock
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tao Zu
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Monica Banez-Coronel
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tammy Reid
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hirokazu Furuya
- Department of Neurology, Kochi Medical School, Kochi University, Kochi, Japan.,Department of Neurology, Neuro-Muscular Center, NHO Omuta Hospital, Fukuoka, Japan
| | - H Brent Clark
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Juan C Troncoso
- Department of Pathology and Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Christopher A Ross
- Department of Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pharmacology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Huntington's Disease Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - S H Subramony
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tetsuo Ashizawa
- Department of Neurology, Houston Methodist Hospital, Houston, TX, USA
| | - Eric T Wang
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Anthony T Yachnis
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Laura Pw Ranum
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA .,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.,Genetics Institute, University of Florida, Gainesville, FL, USA
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6
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Ehara A, Maekawa M, Hori Y, Nakadate K, Ueda S. Age-related behavioral, morphological and physiological changes in the hippocampus of zitter rats. Anat Sci Int 2017; 93:332-339. [DOI: 10.1007/s12565-017-0416-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
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7
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Enhanced Expression of Trib3 during the Development of Myelin Breakdown in dmy Myelin Mutant Rats. PLoS One 2016; 11:e0168250. [PMID: 27977799 PMCID: PMC5158197 DOI: 10.1371/journal.pone.0168250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/28/2016] [Indexed: 12/02/2022] Open
Abstract
The demyelination (dmy) rat exhibits hind limb ataxia and severe myelin breakdown in the central nervous system. The causative gene of dmy rats is the MRS2 magnesium transporter gene. Tribbles homolog 3 (Trib3) is a pseudokinase molecule that modifies certain signal pathways, and its expression is increased in response to various stresses. Here we sought to clarify the mechanism of myelin breakdown by focusing Trib3, which is remarkably up-regulated in dmy rats. The expression of Trib3 mRNA was significantly increased at 4, 5, 6, 7 and 8 weeks of age in the dmy rats, prior to the prominent myelin breakdown between 7 and 10 weeks of age. The expression level of Trib3 was increased concurrently with the progression of the clinical and pathological conditions in the dmy rats. Double immunofluorescence demonstrated that TRIB3 was mainly expressed in neurons and oligodendrocytes and localized in the Golgi apparatus. Our findings indicate that Trib3 may be associated with the pathogenic mechanism of dmy rats.
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8
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Duncan ID, Radcliff AB. Inherited and acquired disorders of myelin: The underlying myelin pathology. Exp Neurol 2016; 283:452-75. [PMID: 27068622 PMCID: PMC5010953 DOI: 10.1016/j.expneurol.2016.04.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 01/26/2023]
Abstract
Remyelination is a major therapeutic goal in human myelin disorders, serving to restore function to demyelinated axons and providing neuroprotection. The target disorders that might be amenable to the promotion of this repair process are diverse and increasing in number. They range primarily from those of genetic, inflammatory to toxic origin. In order to apply remyelinating strategies to these disorders, it is essential to know whether the myelin damage results from a primary attack on myelin or the oligodendrocyte or both, and whether indeed these lead to myelin breakdown and demyelination. In some disorders, myelin sheath abnormalities are prominent but demyelination does not occur. This review explores the range of human and animal disorders where myelin pathology exists and focusses on defining the myelin changes in each and their cause, to help define whether they are targets for myelin repair therapy. We reviewed myelin disorders of the CNS in humans and animals. Myelin damage results from primary attack on the oligodendrocyte or myelin sheath. All major categories of disease can affect CNS myelin. Myelin vacuolation is common, yet does not always result in demyelination.
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Affiliation(s)
- Ian D Duncan
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States.
| | - Abigail B Radcliff
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States
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9
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Izawa T, Yamate J, Franklin RJ, Kuwamura M. Abnormal iron accumulation is involved in the pathogenesis of the demyelinating dmy rat but not in the hypomyelinating mv rat. Brain Res 2010; 1349:105-14. [PMID: 20599839 DOI: 10.1016/j.brainres.2010.06.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 06/10/2010] [Accepted: 06/10/2010] [Indexed: 10/19/2022]
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10
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Walker WP, Gunn TM. Shades of meaning: the pigment-type switching system as a tool for discovery. Pigment Cell Melanoma Res 2010; 23:485-95. [PMID: 20465596 DOI: 10.1111/j.1755-148x.2010.00721.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The pigment-type switching system, which controls whether melanocytes produce black/brown eumelanin or yellow/red pheomelanin, is responsible for many familiar coat coloration patterns in both domestic and wild mammals. In conjunction with the accessory proteins attractin and mahogunin ring finger 1, endogenous agonists and antagonists modulate signaling by the melanocortin 1 receptor to determine pigment type. Mutations in pigment-type switching genes can cause a variety of pleiotropic phenotypes, and these are often similar between mutants at different loci because the proteins encoded by these genes act together as part of conserved molecular pathways that are deployed in multiple biological contexts. When this is the case, pigment-type switching provides a powerful model system for elucidating the shared molecular mechanisms underlying the pigmentary and non-pigmentary phenotypes. This review outlines the current understanding of the pigment-type switching pathway and discusses the opportunities that exist for exploring the molecular basis of pleiotropic phenotypes using this model system.
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11
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Izawa T, Yamate J, Franklin RJ, Kuwamura M. Abnormal myelinogenesis both in the white and gray matter of the attractin-deficient mv rat. Brain Res 2010; 1312:145-55. [DOI: 10.1016/j.brainres.2009.11.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 11/10/2009] [Accepted: 11/11/2009] [Indexed: 10/20/2022]
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12
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Li J, Wang S, Huang S, Cheng D, Shen S, Xiong C. Attractin gene deficiency contributes to testis vacuolization and sperm dysfunction in male mice. ACTA ACUST UNITED AC 2009; 29:750-4. [DOI: 10.1007/s11596-009-0616-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Indexed: 02/03/2023]
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13
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Scalabrino G. The multi-faceted basis of vitamin B12 (cobalamin) neurotrophism in adult central nervous system: Lessons learned from its deficiency. Prog Neurobiol 2009; 88:203-20. [DOI: 10.1016/j.pneurobio.2009.04.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 03/03/2009] [Accepted: 04/16/2009] [Indexed: 10/20/2022]
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Sakakibara SI, Nakadate K, Ookawara S, Ueda S. Non-cell autonomous impairment of oligodendrocyte differentiation precedes CNS degeneration in the Zitter rat: implications of macrophage/microglial activation in the pathogenesis. BMC Neurosci 2008; 9:35. [PMID: 18394170 PMCID: PMC2323389 DOI: 10.1186/1471-2202-9-35] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 04/05/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The zitter (zi/zi) rat, a loss-of-function mutant of the glycosylated transmembrane protein attractin (atrn), exhibits widespread age-dependent spongiform degeneration, hypomyelination, and abnormal metabolism of reactive oxygen species (ROS) in the brain. To date, the mechanisms underlying these phenotypes have remained unclear. RESULTS Here, we show differentiation defects in zi/zi oligodendrocytes, accompanied by aberrant extension of cell-processes and hypomyelination. Axonal bundles were relatively preserved during postnatal development. With increasing in age, the injured oligodendrocytes in zi/zi rats become pathological, as evidenced by the accumulation of iron in their cell bodies. Immunohistochemical analysis revealed that atrn expression was absent from an oligodendrocyte lineage, including A2B5-positive progenitors and CNPase-positive differentiated cells. The number and distribution of Olig2-positive oligodendrocyte progenitors was unchanged in the zi/zi brain. Furthermore, an in vitro differentiation assay of cultured oligodendrocyte progenitors prepared from zi/zi brains revealed their normal competence for proliferation and differentiation into mature oligodendrocytes. Interestingly, we demonstrated the accelerated recruitment of ED1-positive macrophages/microglia to the developing zi/zi brain parenchyma prior to the onset of hypomyelination. Semiquantitative RT-PCR analysis revealed a significant up-regulation of CD26 and IL1-beta in the zi/zi brain during this early postnatal stage. CONCLUSION We demonstrated that the onset of the impairment of oligodendrocyte differentiation occurs in a non-cell autonomous manner in zi/zi rats. Hypomyelination of oligodendrocytes was not due to a failure of the intrinsic program of oligodendrocytes, but rather, was caused by extrinsic factors that interrupt oligodendrocyte development. It is likely that macrophage/microglial activation in the zi/zi CNS leads to disturbances in oligodendrocyte differentiation via deleterious extrinsic factors, such as the cytokine IL1-beta or ROS. Atrn might be involved in the activation of brain macrophages/microglia by suppressing excessive migration of monocytes into the CNS, or by accelerating the transformation of brain monocytes into resting microglia. Understanding the pathogenesis of the zi/zi rat may provide novel insights into the developmental interaction betweens macrophages/microglia and cells of an oligodendrocyte lineage.
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Affiliation(s)
- Shin-ichi Sakakibara
- Department of Histology and Neurobiology, Dokkyo Medical University School of Medicine, Tochigi, Japan.
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15
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Izawa T, Takenaka S, Ihara H, Kotani T, Yamate J, Franklin RJ, Kuwamura M. Cellular responses in the spinal cord during development of hypomyelination in the mv rat. Brain Res 2008; 1195:120-9. [DOI: 10.1016/j.brainres.2007.12.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 12/10/2007] [Accepted: 12/12/2007] [Indexed: 10/22/2022]
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16
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Nakadate K, Sakakibara SI, Ueda S. Attractin/mahogany protein expression in the rodent central nervous system. J Comp Neurol 2008; 508:94-111. [DOI: 10.1002/cne.21662] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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17
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Azouz A, Gunn TM, Duke-Cohan JS. Juvenile-onset loss of lipid-raft domains in attractin-deficient mice. Exp Cell Res 2006; 313:761-71. [PMID: 17196964 DOI: 10.1016/j.yexcr.2006.11.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 11/09/2006] [Accepted: 11/27/2006] [Indexed: 11/29/2022]
Abstract
Mutations at the attractin (Atrn) locus in mice result in altered pigmentation on an agouti background, higher basal metabolic rate and juvenile-onset hypomyelination leading to neurodegeneration, while studies on human immune cells indicate a chemotaxis regulatory function. The underlying biochemical defect remains elusive. In this report we identify a role for attractin in plasma membrane maintenance. In attractin's absence there is a decline in plasma membrane glycolipid-enriched rafts from normal levels at 8 weeks to a complete absence by 24 weeks. The structural integrity of lipid rafts depends upon cholesterol and sphingomyelin, and can be identified by partitioning within of ganglioside GM(1). Despite a significant fall in cellular cholesterol with maturity, and a lesser fall in both membrane and total cellular GM(1), these parameters lag behind raft loss, and are normal when hypomyelination/neurodegeneration has already begun thus supporting consequence rather than cause. These findings can be recapitulated in Atrn-deficient cell lines propagated in vitro. Further, signal transduction through complex membrane receptor assemblies is not grossly disturbed despite the complete absence of lipid rafts. We find these results compatible with a role for attractin in plasma membrane maintenance and consistent with the proposal that the juvenile-onset hypomyelination and neurodegeneration represent a defect in attractin-mediated raft-dependent myelin biogenesis.
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Affiliation(s)
- Abdallah Azouz
- Department of Medical Oncology, Dana-Farber Cancer Institute, and Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
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18
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Kuwamura M, Kanehara T, Tokuda S, Kumagai D, Yamate J, Kotani T, Nakane Y, Kuramoto T, Serikawa T. Immunohistochemical and morphometrical studies on myelin breakdown in the demyelination (dmy) mutant rat. Brain Res 2006; 1022:110-6. [PMID: 15353220 DOI: 10.1016/j.brainres.2004.07.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2004] [Indexed: 10/26/2022]
Abstract
The demyelination (dmy) rat is a unique mutant exhibiting severe myelin breakdown in the central nervous system (CNS). In this study, we conducted immunohistochemical and morphometrical investigations in the dmy rat. From around 6 weeks of age, the affected rats developed ataxia especially in the hindlimbs. Afterwards, ataxia worsened rapidly, resulting in complete paralysis of the hindlimbs and recumbency. Histopathology at 7 to 10 weeks of age revealed myelin destruction throughout the white matter of the CNS in the dmy rats. The most severely affected lesions were distributed in the corpus callosum, capsula interna, striatum, subcortical white matter, cerebellar peduncle, and ventral and lateral parts of the spinal cord. Immunohistochemistry demonstrated prominent astrogliosis and many ED-1 positive macrophages in the myelin-destructed areas. Until the 4th week, no significant differences in myelin thickness and fiber diameter were found between dmy and control rats. However, from 5 weeks of age, myelin thickness of residual myelinated fibers in dmy rats became significantly less than that in controls. These data indicated that the dmy phenotype shows a prolonged period of myelin destruction, suggesting that dmy mutation affects the adequate maintenance of myelin.
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Affiliation(s)
- Mitsuru Kuwamura
- Laboratory of Veterinary Pathology, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
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Di Giovanni S, Faden AI, Yakovlev A, Duke-Cohan JS, Finn T, Thouin M, Knoblach S, De Biase A, Bregman BS, Hoffman EP. Neuronal plasticity after spinal cord injury: identification of a gene cluster driving neurite outgrowth. FASEB J 2004; 19:153-4. [PMID: 15522907 DOI: 10.1096/fj.04-2694fje] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Functional recovery after spinal cord injury (SCI) may result in part from axon outgrowth and related plasticity through coordinated changes at the molecular level. We employed microarray analysis to identify a subset of genes the expression patterns of which were temporally coregulated and correlated to functional recovery after SCI. Steady-state mRNA levels of this synchronously regulated gene cluster were depressed in both ventral and dorsal horn neurons within 24 h after injury, followed by strong re-induction during the following 2 wk, which paralleled functional recovery. The identified cluster includes neuritin, attractin, microtubule-associated protein 1a, and myelin oligodendrocyte protein genes. Transcriptional and protein regulation of this novel gene cluster was also evaluated in spinal cord tissue and in single neurons and was shown to play a role in axonal plasticity. Finally, in vitro transfection experiments in primary dorsal root ganglion cells showed that cluster members act synergistically to drive neurite outgrowth.
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Affiliation(s)
- Simone Di Giovanni
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
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20
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Abstract
Rat myelin vacuolation mutation at the Attractin locus (Atrn(mv)) is a genomic deletion including the whole exon 1 of the Atrn gene. The precise size and location of the deleted region has not yet been identified because of poor information on genomic organization of the rat Atrn gene. Here, we identified the breakpoints of the Atrn(mv) mutation, using a draft sequence of the rat genome. In the Atrn(mv/mv) rat, a 6,914-bp genomic region was deleted. Primers flanked 5'- and 3'- breakpoints amplified the Atrn(mv) allele but not the wild-type allele. This primer set enables us to distinguish Atrn(mv/+) heterozygous rats from Atrn(+/+) rats, and will contribute to the efficient production of Atrn(mv/mv) rats.
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Affiliation(s)
- Satoko Tokuda
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Haqq AM, René P, Kishi T, Khong K, Lee CE, Liu H, Friedman JM, Elmquist JK, Cone RD. Characterization of a novel binding partner of the melanocortin-4 receptor: attractin-like protein. Biochem J 2004; 376:595-605. [PMID: 14531729 PMCID: PMC1223823 DOI: 10.1042/bj20031241] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2003] [Revised: 09/15/2003] [Accepted: 10/07/2003] [Indexed: 11/17/2022]
Abstract
The gene dosage effect of the MC4-R (melanocortin 4 receptor) on obesity suggests that regulation of MC4-R expression and function is critically important to the central control of energy homoeostasis. In order to identify putative MC4-R regulatory proteins, we performed a yeast two-hybrid screen of a mouse brain cDNA library using the mouse MC4-R intracellular tail (residues 303-332) as bait. We report here on one positive clone that shares 63% amino acid identity with the C-terminal part of the mouse attractin gene product, a single-transmembrane-domain protein characterized as being required for agouti signalling through the melanocortin 1 receptor. We confirmed a direct interaction between this ALP (attractin-like protein) and the C-terminus of the mouse MC4-R by glutathione S-transferase pulldown experiments, and mapped the regions involved in this interaction using N- and C-terminal truncation constructs; residues 303-313 in MC4-R and residues 1280-1317 in ALP are required for binding. ALP is highly expressed in brain, but also in heart, lung, kidney and liver. Furthermore, co-localization analyses in mice showed co-expression of ALP in cells expressing MC4-R in a number of regions known to be important in the regulation of energy homoeostasis by melanocortins, such as the paraventricular nucleus of hypothalamus and the dorsal motor nucleus of the vagus.
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Affiliation(s)
- Andrea M Haqq
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
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