1
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Moussavi Nik SH, Porter T, Newman M, Bartlett B, Khan I, Sabale M, Eccles M, Woodfield A, Groth D, Dore V, Villemagne VL, Masters CL, Martins RN, Laws SM, Lardelli M, Verdile G. Relevance of a Truncated PRESENILIN 2 Transcript to Alzheimer's Disease and Neurodegeneration. J Alzheimers Dis 2021; 80:1479-1489. [PMID: 33720885 DOI: 10.3233/jad-201133] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The PRESENILIN genes (PSEN1, PSEN2) encoding for their respective proteins have critical roles in many aspects of Alzheimer's disease (AD) pathogenesis. The PS2V transcript of PSEN2 encodes a truncated protein and is upregulated in AD brains; however, its relevance to AD and disease progression remains to be determined. OBJECTIVE Assess transcript levels in postmortem AD and non-AD brain tissue and in lymphocytes collected under the Australian Imaging Biomarker and Lifestyle (AIBL) study. METHODS Full length PSEN2 and PS2V transcript levels were assessed by quantitative digital PCR in postmortem brain tissue (frontal cortex and hippocampus) from control, AD, frontotemporal dementia (FTD), and Lewy body dementia (LBD). Transcript levels were also assessed in lymphocytes obtained from the Perth subset of the AIBL study (n = 160). Linear regression analysis was used to assess correlations between transcript copy number and brain volume and neocortical amyloid load. RESULTS PS2V levels increased in AD postmortem brain but PS2V was also present at significant levels in FTD and LBD brains. PS2V transcript was detected in lymphocytes and PS2V/PSEN2 ratios were increased in mild cognitive impairment (p = 0.024) and AD (p = 0.019) groups compared to control group. Increased ratios were significantly correlated with hippocampal volumes only (n = 62, β= -0.269, p = 0.03). CONCLUSION Taken together, these results suggest that PS2V may be a marker of overall neurodegeneration.
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Affiliation(s)
- Seyyed Hani Moussavi Nik
- University of Adelaide, School of Biological Sciences, Centre for Molecular Pathology, Adelaide, SA, Australia
| | - Tenielle Porter
- Collaborative Genomics and Translation Group, Strategic Research Centre for Precision Health, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Morgan Newman
- University of Adelaide, School of Biological Sciences, Centre for Molecular Pathology, Adelaide, SA, Australia
| | - Benjamin Bartlett
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia.,Department of Advanced Clinical and Translational Cardiovascular Imaging, Harry Perkins Institute of Medical Research, Murdoch, Western Australia, Australia.,School of Medicine, University of Western Australia, Crawley, Western Australia, Australia
| | - Imran Khan
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Miheer Sabale
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia.,Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia
| | - Melissa Eccles
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Amy Woodfield
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - David Groth
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Vincent Dore
- Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, VIC, Australia
| | - Victor L Villemagne
- Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, VIC, Australia.,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Colin L Masters
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Ralph N Martins
- Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia.,School of Medical and Health Sciences, Edith Cowan University, Western Australia, Australia
| | - Simon M Laws
- Collaborative Genomics and Translation Group, Strategic Research Centre for Precision Health, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Michael Lardelli
- University of Adelaide, School of Biological Sciences, Centre for Molecular Pathology, Adelaide, SA, Australia
| | - Giuseppe Verdile
- Collaborative Genomics and Translation Group, Strategic Research Centre for Precision Health, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
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2
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Dai MH, Zheng H, Zeng LD, Zhang Y. The genes associated with early-onset Alzheimer's disease. Oncotarget 2018; 9:15132-15143. [PMID: 29599933 PMCID: PMC5871104 DOI: 10.18632/oncotarget.23738] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 10/14/2017] [Indexed: 01/31/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder that accounts for the most cases of dementia, which is characterized by the deposition of dense plaques of amyloid beta (Aβ) plaques and neurofibrillary tangles consisting of hyperphosphorylated tau. The two main types of AD can be classified as early-onset AD (EOAD, onset < 65 years) and late-onset AD (LOAD, onset ≥ 65 years). Evidence from family and twin studies indicate that genetic factors are estimated to play a role in at least 80% of AD cases. The first milestone with linkage analysis revealed the mutations in APP, PSEN1, and PSEN2 genes that cause EOAD. But pathogenic mutations in these three genes can only explain a small fraction of EOAD families. The additional disease-causing genes have not yet been identified. This review provides an overview of the genetic basis of EOAD and the relationship between the functions of these risk genes and the neuropathologic features of AD. A better understanding of genetic mechanisms underlying EOAD pathogenesis and the potentially molecular mechanisms of neurodegeneration will lead to the development of effective diagnosis and treatment strategies for this devastating disease.
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Affiliation(s)
- Meng-Hui Dai
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hui Zheng
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Ling-Dan Zeng
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yan Zhang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
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3
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Early onset Alzheimer's disease and oxidative stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:375968. [PMID: 24669286 PMCID: PMC3942075 DOI: 10.1155/2014/375968] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/18/2013] [Indexed: 01/30/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in elderly adults. It is estimated that 10% of the world's population aged more than 60-65 years could currently be affected by AD, and that in the next 20 years, there could be more than 30 million people affected by this pathology. One of the great challenges in this regard is that AD is not just a scientific problem; it is associated with major psychosocial and ethical dilemmas and has a negative impact on national economies. The neurodegenerative process that occurs in AD involves a specific nervous cell dysfunction, which leads to neuronal death. Mutations in APP, PS1, and PS2 genes are causes for early onset AD. Several animal models have demonstrated that alterations in these proteins are able to induce oxidative damage, which in turn favors the development of AD. This paper provides a review of many, although not all, of the mutations present in patients with familial Alzheimer's disease and the association between some of these mutations with both oxidative damage and the development of the pathology.
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4
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Chen XF, Zhang YW, Xu H, Bu G. Transcriptional regulation and its misregulation in Alzheimer's disease. Mol Brain 2013; 6:44. [PMID: 24144318 PMCID: PMC3854070 DOI: 10.1186/1756-6606-6-44] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 10/15/2013] [Indexed: 11/25/2022] Open
Abstract
Alzheimer’s disease (AD) is a devastating neurodegenerative disorder characterized by loss of memory and cognitive function. A key neuropathological event in AD is the accumulation of amyloid-β (Aβ) peptide. The production and clearance of Aβ in the brain are regulated by a large group of genes. The expression levels of these genes must be fine-tuned in the brain to keep Aβ at a balanced amount under physiological condition. Misregulation of AD genes has been found to either increase AD risk or accelerate the disease progression. In recent years, important progress has been made in uncovering the regulatory elements and transcriptional factors that guide the expression of these genes. In this review, we describe the mechanisms of transcriptional regulation for the known AD genes and the misregualtion that leads to AD susceptibility.
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Affiliation(s)
- Xiao-Fen Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, 361102 Xiamen, Fujian, People's Republic of China.
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5
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Abstract
Alzheimer disease (AD) is the most common causes of neurodegenerative disorder in the elderly individuals. Clinically, patients initially present with short-term memory loss, subsequently followed by executive dysfunction, confusion, agitation, and behavioral disturbances. Three causative genes have been associated with autosomal dominant familial AD (APP, PSEN1, and PSEN2) and 1 genetic risk factor (APOEε4 allele). Identification of these genes has led to a number of animal models that have been useful to study the pathogenesis underlying AD. In this article, we provide an overview of the clinical and genetic features of AD.
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Affiliation(s)
- Lynn M. Bekris
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Chang-En Yu
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Thomas D. Bird
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Debby W. Tsuang
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
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6
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Morikawa T, Manabe T. Aberrant regulation of alternative pre-mRNA splicing in schizophrenia. Neurochem Int 2010; 57:691-704. [DOI: 10.1016/j.neuint.2010.08.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/07/2010] [Accepted: 08/12/2010] [Indexed: 01/06/2023]
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7
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Newman M, Verdile G, Martins RN, Lardelli M. Zebrafish as a tool in Alzheimer's disease research. Biochim Biophys Acta Mol Basis Dis 2010; 1812:346-52. [PMID: 20920580 DOI: 10.1016/j.bbadis.2010.09.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Accepted: 09/21/2010] [Indexed: 10/19/2022]
Abstract
Alzheimer's disease is the most prevalent form of neurodegenerative disease. Despite many years of intensive research our understanding of the molecular events leading to this pathology is far from complete. No effective treatments have been defined and questions surround the validity and utility of existing animal models. The zebrafish (and, in particular, its embryos) is a malleable and accessible model possessing a vertebrate neural structure and genome. Zebrafish genes orthologous to those mutated in human familial Alzheimer's disease have been defined. Work in zebrafish has permitted discovery of unique characteristics of these genes that would have been difficult to observe with other models. In this brief review we give an overview of Alzheimer's disease and transgenic animal models before examining the current contribution of zebrafish to this research area. This article is part of a Special Issue entitled Zebrafish Models of Neurological Diseases.
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Affiliation(s)
- Morgan Newman
- Discipline of Genetics, The University of Adelaide, SA 5005, Australia
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8
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Suh YH. Pathogenesis of Alzheimer's Dementia. JOURNAL OF THE KOREAN MEDICAL ASSOCIATION 2006. [DOI: 10.5124/jkma.2006.49.8.717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Yoo-Hun Suh
- Department of Pharmacology, Seoul National University College of Medicine, Korea.
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9
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Marambaud P, Robakis NK. Genetic and molecular aspects of Alzheimer's disease shed light on new mechanisms of transcriptional regulation. GENES BRAIN AND BEHAVIOR 2005; 4:134-46. [PMID: 15810902 DOI: 10.1111/j.1601-183x.2005.00086.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Rapid advances made in biological research aimed at understanding the molecular basis of the pathogenesis of Alzheimer's disease have led to the characterization of a novel catalytic activity termed gamma-secretase. First described for its beta-amyloid-producing function, gamma-secretase is now actively studied for its role in a novel signal transduction paradigm, which implicates cell-surface receptor proteolysis and direct surface-to-nucleus signal transduction. gamma-Secretase targets numerous type I protein receptors involved in diverse functions ranging from normal development to neurodegeneration. In this Review we discuss how the study of the genetic and molecular aspects of Alzheimer's disease has revealed a dual role of gamma-secretase in transcriptional regulation and in the pathogenesis of familial Alzheimer's disease.
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Affiliation(s)
- P Marambaud
- Department of Psychiatry and Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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10
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Higashide S, Morikawa K, Okumura M, Kondo S, Ogata M, Murakami T, Yamashita A, Kanemoto S, Manabe T, Imaizumi K. Identification of regulatory cis-acting elements for alternative splicing of presenilin 2 exon 5 under hypoxic stress conditions. J Neurochem 2005; 91:1191-8. [PMID: 15569262 DOI: 10.1111/j.1471-4159.2004.02798.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
An alternatively spliced form of the presenilin 2 (PS2) gene lacking exon 5 (PS2V) was found in human brains with sporadic Alzheimer's disease. PS2V was induced by hypoxic stress in human neuroblastoma SK-N-SH cells, indicating that hypoxic stress affects the splicing machineries for PS2 exon 5. Here, we identified the critical cis-acting element (sec 2) on the PS2 pre-mRNA responsible for the aberrant splicing of PS2 exon 5 under hypoxic stress conditions. The element was composed of 23 nucleotides in exon 5 and RNA structural analyses showed a stem-loop structure in this sequence. Treatment with an antisense oligonucleotide directed toward the cis-acting element caused an increase in exon 5 inclusion. These results indicate that the sec 2 identified in this study is a novel regulatory element for exon 5 splicing under stress conditions and that trans-acting factors could specifically bind to the element to skip exon 5 of PS2.
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Affiliation(s)
- Satoshi Higashide
- Division of Structural Cellular Biology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
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11
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Smith MJ, Sharples RA, Evin G, McLean CA, Dean B, Pavey G, Fantino E, Cotton RGH, Imaizumi K, Masters CL, Cappai R, Culvenor JG. Expression of truncated presenilin 2 splice variant in Alzheimer's disease, bipolar disorder, and schizophrenia brain cortex. ACTA ACUST UNITED AC 2004; 127:128-35. [PMID: 15306129 DOI: 10.1016/j.molbrainres.2004.05.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2004] [Indexed: 11/19/2022]
Abstract
We have analysed the expression of a truncated variant presenilin 2 protein (PS2V) in frontal cortex from subjects with Alzheimer's disease (AD) and age-matched controls, and compared these results with cortex from bipolar disorder (BP), schizophrenia (SZ) and controls in a second brain bank collection. PS2V protein was detected as a 14 kDa species with antibodies directed to the PS2 N-terminal region and to the new C-terminus created by alternative transcription. PS2V protein levels were significantly increased by two-fold in AD cortex, as compared to age-matched controls. In tissue from the second collection, levels of PS2V were markedly elevated in some BP and SZ cases, but there was no overall difference between diagnostic groups. Our findings support previous evidence for increased expression of this variant PS2 isoform in sporadic AD and suggest this isoform may contribute to neurodegeneration.
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Affiliation(s)
- Margaret J Smith
- Department of Pathology, The University of Melbourne, and The Mental Health Research Institute of Victoria, Grattan St., Parkville, Victoria 3010, Australia
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12
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Takahashi N, Kariya S, Hirano M, Ueno S. Two novel spliced presenilin 2 transcripts in human lymphocyte with oxidant stress and brain. Mol Cell Biochem 2004; 252:279-83. [PMID: 14577603 DOI: 10.1023/a:1025537021543] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We identified two novel spliced human presenilin 2 (PS2) transcripts. The first, PS2deltaEx3-7, lacked part ofexon 3, all of exons 4, 5, and 6, and part of exon 7, resulting in an in-frame shift and inclusion of the natural start codon and proteolytic region. This transcript was detected in cerebral cortex and peripheral lymphocytes. The second transcript, PS2deltaEx4, lacked exon 4, resulting in a frame shift and inclusion of the natural start codon, and was transcribed in peripheral lymphocytes and heart but not in brain. Quantitative RT-PCR analysis revealed that the PS2deltaEx3-7 significantly increased in lymphocytes treated with H2O2, suggesting that this transcript is a novel genetic marker that can be used to study the pathogenesis of Alzheimer's disease.
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13
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Rocchi A, Pellegrini S, Siciliano G, Murri L. Causative and susceptibility genes for Alzheimer's disease: a review. Brain Res Bull 2003; 61:1-24. [PMID: 12788204 DOI: 10.1016/s0361-9230(03)00067-4] [Citation(s) in RCA: 216] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most common type of dementia in the elderly population. Three genes have been identified as responsible for the rare early-onset familial form of the disease: the amyloid precursor protein (APP) gene, the presenilin 1 (PSEN1) gene and the presenilin 2 (PSEN2) gene. Mutations in these genes, however, account for less than 5% of the total number of AD cases. The remaining 95% of AD patients are mostly sporadic late-onset cases, with a complex aetiology due to interactions between environmental conditions and genetic features of the individual. In this paper, we review the most important genes supposed to be involved in the pathogenesis of AD, known as susceptibility genes, in an attempt to provide a comprehensive picture of what is known about the genetic mechanisms underlying the onset and progression of AD. Hypotheses about the role of each gene in the pathogenic pathway are discussed, taking into account the functions and molecular features, if known, of the coded protein. A major susceptibility gene, the apolipoprotein E (APOE) gene, found to be associated with sporadic late-onset AD cases and the only one, whose role in AD has been confirmed in numerous studies, will be included in a specific chapter. As the results reported by association studies are conflicting, we conclude that a better understanding of the complex aetiology that underlies AD may be achieved likely through a multidisciplinary approach that combines clinical and neurophysiological characterization of AD subtypes and in vivo functional brain imaging studies with molecular investigations of genetic components.
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Affiliation(s)
- A Rocchi
- Department of Neurosciences, Neurological Clinics, University of Pisa Medical School, Via Roma 67, 56126 Pisa, Italy
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14
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Abstract
The presenilins are evolutionarily conserved transmembrane proteins that regulate cleavage of certain other proteins in their transmembrane domains. The clinical significance of this regulation is shown by the contribution of presenilin mutations to 20-50% of early-onset cases of inherited Alzheimer's disease. Although the precise molecular mechanism underlying presenilin function or dysfunction remains elusive, presenilins are thought to be part of a complex of proteins that has 'gamma-secretase cleavage' activity, which is clearly central in the pathogenesis of Alzheimer's disease. Mutations in presenilins increase the production of the longer isoforms of amyloid beta peptide, which are neurotoxic and prone to self-aggregation. Biochemical studies indicate that the presenilins do not act alone but operate within large heteromeric protein complexes, whose components and enzymatic core are the subject of much study and controversy; one essential component is nicastrin. The presenilin primary sequence is remarkably well conserved in eukaryotes, suggesting some functional conservation; indeed, defects caused by mutations in the nemotode presenilin homolog can be rescued by human presenilin.
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Affiliation(s)
- Anurag Tandon
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Queen's Park Crescent West, Toronto M5S 3H2, Canada.
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15
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Morihara T, Katayama T, Sato N, Yoneda T, Manabe T, Hitomi J, Abe H, Imaizumi K, Tohyama M. Absence of endoproteolysis but no effects on amyloid beta production by alternative splicing forms of presenilin-1, which lack exon 8 and replace D257A. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2000; 85:85-90. [PMID: 11146110 DOI: 10.1016/s0169-328x(00)00229-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is well known that presenilin-1 (PS1) is involved in cleavage of amyloid precursor protein (APP) at the gamma-secretase site, and that the amino acids residues of D257 and D385 in PS1 are critical for this cleavage of APP and the endoproteolysis of itself. An alternatively spliced form of PS1 skipping exon 8 (PS1d8), which has D257A at the splice junction of exon 7/9, is expressed in human brain and in some cell lines. In this study, we examined production of Amyloid beta (A beta) and the endoproteolysis of the holoproteins in PS1d8-expressing neuroblastoma cells. Western blotting showed an absence of endoproteolysis in PS1d8. However, PS1d8 did not affect the production of A beta, which is different from the artificial point mutant PS1D257A. These results suggest that endoproteolysis of PS1 and gamma-secretase activity could be independent.
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Affiliation(s)
- T Morihara
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka Suita, Osaka 565-0871, Japan
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16
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Abstract
The presenilins (PS-1 and PS-2) are 2 members of a novel family of genes encoding integral membrane proteins recently implicated in Alzheimer's disease (AD) pathology. To date, 43 mutations have been identified in PS-1 and 2 in PS-2 that lead to familial presenile AD (onset before age 65 years). The normal and pathological functions of the PS proteins (ps-1 and ps-2) are unknown, but their high degree of homology predicts similar biological activities. Homologies with ps from other species suggest that they may play a role in intracellular protein sorting and trafficking, in intercellular cell signaling, or in cell death. Since to date only missense mutations and in-frame deletions were identified, it is believed that mutated ps act through either a gain of (dys-)function or a dominant negative effect. In vivo and in vitro studies have linked PS mutations to amyloid deposition, an early pathological event in AD brains.
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Affiliation(s)
- M Cruts
- Flanders Interuniversity Institute for Biotechnology, BornBunge Foundation, University of Antwerp, Department of Biochemistry, Antwerpen, Belgium
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17
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Capell A, Steiner H, Romig H, Keck S, Baader M, Grim MG, Baumeister R, Haass C. Presenilin-1 differentially facilitates endoproteolysis of the beta-amyloid precursor protein and Notch. Nat Cell Biol 2000; 2:205-11. [PMID: 10783238 DOI: 10.1038/35008626] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mutations in the presenilin-1 (PS1) gene are associated with Alzheimer's disease and cause increased secretion of the neurotoxic amyloid-beta peptide (Abeta). Critical intramembraneous aspartates at residues 257 and 385 are required for the function of PS1 protein. Here we investigate the biological function of a naturally occurring PS1 splice variant (PS1 Deltaexon 8), which lacks the critical aspartate 257. Cell lines that stably express PS1 Deltaexon 8 or a PS1 protein in which aspartate residue 257 is mutated secrete significant levels of Abeta, whereas Abeta generation is severely reduced in cells transfected with PS1 containing a mutation of aspartate 385. In contrast, endoproteolytic processing of Notch is almost completely inhibited in cell lines expressing any of the PS1 variants that lack one of the critical aspartates. These data indicate that PS1 may differentially facilitate gamma-secretase-mediated generation of Abeta and endoproteolysis of Notch.
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Affiliation(s)
- A Capell
- Adolf Butenandt-Institute, Department of Biochemistry, Laboratory for Alzheimer's Disease Research, Ludwig-Maximilians-University, 80336 Munich, Germany
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18
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Nowotny P, Gorski SM, Han SW, Philips K, Ray WJ, Nowotny V, Jones CJ, Clark RF, Cagan RL, Goate AM. Posttranslational modification and plasma membrane localization of the Drosophila melanogaster presenilin. Mol Cell Neurosci 2000; 15:88-98. [PMID: 10662508 DOI: 10.1006/mcne.1999.0805] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mutations in two genes, presenilin 1 (PS1) and presenilin 2, are linked to early onset cases of familial Alzheimer's disease. The presenilins are thought to contribute to the pathogenesis of Alzheimer's disease by directly or indirectly affecting the proteolytic processing of the amyloid precursor protein. They have also been implicated in the proteolytic processing of Notch. In PS1-deficient mammalian cells, the proteolytic release of the Notch intracellular domain is reduced. Likewise, loss-of-function mutations in Drosophila presenilin (Psn) prevent the production of the intracellular Notch signaling fragment and lead to phenotypes resembling Notch mutants. Here we characterize the Drosophila Psn protein and demonstrate that it undergoes a proteolytic cleavage. We describe Psn expression at different developmental stages of the fly and show Psn localization near both apical and basal plasma membranes. Furthermore, we demonstrate that portions of the Psn protein span the plasma membrane in S2 cells.
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Affiliation(s)
- P Nowotny
- Department of Psychiatry, Department of Molecular Biology and Pharmacology, Institute for Biomedical Computing, Washington University School of Medicine, 4559 Scott Avenue, St. Louis, Missouri, 63110, USA
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19
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Sato N, Hori O, Yamaguchi A, Lambert JC, Chartier-Harlin MC, Robinson PA, Delacourte A, Schmidt AM, Furuyama T, Imaizumi K, Tohyama M, Takagi T. A novel presenilin-2 splice variant in human Alzheimer's disease brain tissue. J Neurochem 1999; 72:2498-505. [PMID: 10349860 DOI: 10.1046/j.1471-4159.1999.0722498.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mutations in the presenilin-1 (PS-1) and presenilin-2 (PS-2) genes account for the majority of cases of early-onset familial Alzheimer's disease (AD). Alternative splicing forms of the PS-1 and PS-2 gene products have previously been reported in fibroblast and brain tissue from both familial and sporadic AD patients, as well as from normal tissues and cell lines. We demonstrate here unusual alternative splicing of the PS-2 gene that leads to the generation of mRNA lacking exon 5 in human brain tissue. This product was more frequently detected in brain tissue from sporadic AD patients (70.0%; 21 of 30) than from normal age-matched controls (17.6%; three of 17). In cultured neuroblastoma cells, this splice variant was generated in hypoxia but not under other forms of cellular stress. Hypoxia-mediated induction of this splice variant was blocked by pretreatment of neuroblastoma cells with the protein synthesis inhibitor cycloheximide or antioxidants such as N-acetylcysteine and diphenyl iodonium, suggesting that hypoxia-mediated oxidant stress might, at least in part, underlie the alternative splicing of PS-2 mRNA through de novo protein synthesis. Furthermore, the stable transfectants of this splice variant produced the N-terminal part of PS-2 protein (15 kDa) and were more susceptible to cellular stresses than control transfectants. These results suggest the possibility that altered presenilin gene products in stress conditions may also participate in the pathogenesis of AD.
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Affiliation(s)
- N Sato
- Tanabe Seiyaku Co., Ltd., Department of Anatomy and Neuroscience, Osaka University Medical School, Suita, Japan
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20
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Abstract
Most of early-onset forms of Alzheimer's disease (AD) are caused by inherited mutations located on chromosomes 14 and 1, the gene products of which have been recently identified and referred to as presenilins 1 (PS1) and 2 (PS2), respectively. The first phenotypic alterations triggered by mutated PS were reported to be an increased production of the amyloid peptide (Abeta) and, more precisely, its 42 amino-acids long counterpart Abeta42. This overproduction is thought to be responsible for the genesis of the senile plaques that invade the cortical and subcortical areas of these AD-affected brains. The discovery of PSs has triggered numerous studies aimed at better understanding their normal physiology and the dysfunctions brought by the mutations that could explain, at least in part, the neurodegenerative process taking place in this syndrome. In this review, I will focus on the structural aspects of PS and on the various posttranscriptional events they undergo. I will also briefly discuss that current hypotheses concerning their normal functions and the influence of FAD-linked mutations.
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Affiliation(s)
- F Checler
- Institut de Pharmacologie Moléculaire et Cellulaire, UPR 411 du CNRS, Sophia Antipolis, Valbonne, France
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21
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Walter J, Schindzielorz A, Grünberg J, Haass C. Phosphorylation of presenilin-2 regulates its cleavage by caspases and retards progression of apoptosis. Proc Natl Acad Sci U S A 1999; 96:1391-6. [PMID: 9990034 PMCID: PMC15473 DOI: 10.1073/pnas.96.4.1391] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations within the Presenilin-2 (PS-2) gene are associated with early onset familial Alzheimer's disease. The gene encodes a polytopic transmembrane protein that undergoes endoproteolytic processing resulting in the generation of N-terminal and C-terminal fragments (CTFs). PS-2 is also cleaved by proteases of the caspase family during apoptotic cell death. CTFs of PS-2 were shown to inhibit apoptosis, suggesting an important role in the regulation of programmed cell death. Recently, we found that the CTF of PS-2 is phosphorylated in vivo. We mapped the in vivo phosphorylation sites of PS-2 to serine residues 327 and 330, which are localized immediately adjacent to the cleavage sites of caspases after aspartate residues 326 and 329. Phosphorylation of PS-2 inhibits its cleavage by caspase-3. This effect can be mimicked by substitutions of serines 327 and 330 by aspartate or glutamate. In addition, the uncleavable form of PS-2 CTF was found to enhance its antiapoptotic properties, leading to a slower progression of apoptosis. These results demonstrate that PS-2 cleavage as well as its function in apoptosis can be regulated by protein phosphorylation. Alterations in the phosphorylation of PS-2 may therefore promote the pathogenesis of AD by affecting the susceptibility of neurons to apoptotic stimuli.
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Affiliation(s)
- J Walter
- Central Institute of Mental Health, Department of Molecular Biology, J5, 68159 Mannheim, Germany
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22
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Velez-Pardo C, Jimenez Del Rio M, Lopera F. Familial Alzheimer's disease: oxidative stress, beta-amyloid, presenilins, and cell death. GENERAL PHARMACOLOGY 1998; 31:675-81. [PMID: 9809462 DOI: 10.1016/s0306-3623(98)00189-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
1. The basic etiology of Alzheimer's disease remains unknown, although four genes have so far been involved: beta-amyloid precursor protein, presenilin-1, presenilin-2 and apolipoprotein E genes. 2. The largest familial Alzheimer's disease (FAD) kindred so far reported belong to a point mutation in codon 280 that results in a glutamic acid-to-alanine substitution in presenilin-1 characterized in Antioquia, Colombia. 3. A hypothetical unified molecular mechanism model of cell death in FAD mediated by presenilin-1, beta-amyloid, and oxidative stress is proposed as an attempt to explain the mechanisms of neuronal loss in this neurodegenerative disorder.
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Affiliation(s)
- C Velez-Pardo
- Department of Neurology, University Hospital, Medellin, Colombia
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23
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Abstract
Presenilin-1 (PS-1) is localized to chromosome 14 and presenilin-2 (PS-2) to chromosome 1. Mutations in these genes, primarily in PS-1, account for an estimated 60% of early onset familial Alzheimer's disease cases (FAD), while FAD cases account for about 10% of all Alzheimer's disease (AD) cases. The mutations are minor but are 100% penetrant, suggesting that the proteins have acquired a toxic gain in function. The proteins have multiple transmembrane domains and have been reported to be localized to the Golgi apparatus, endoplasmic reticulum, nuclear membranes and cell surface membranes. They are thought to have functions associated with vesicular trafficking, Notch signaling and apoptosis. PS mutants show relative increases in the amount of A beta42/43 compared with A beta40 in plasma, fibroblasts and brain, observations which have been taken as a possible mechanism of their role in AD. In brain, the mRNAs for these two genes are localized primarily in neurons, with the strongest in situ hybridization signals being observed in the hippocampus, cerebellum and cerebral cortex. In AD, signals detected in the hippocampus are weaker than those in normals, while signals in the cerebellum are comparable. Immunohistochemical localization of the proteins is also primarily in neurons, and, at least for PS-1, is reduced in AD affected areas. PS-1 is localized to granular structures which are most abundant in cell bodies and dendrites. The functions of the presenilins are not yet known, but available evidence points to pyramidal neurons as the most logical site for pathological change in AD.
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Affiliation(s)
- P L McGeer
- Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, Canada
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24
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Tanahashi H, Tabira T. Cloning of the cDNA encoding rat presenilin-2. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1396:259-62. [PMID: 9545577 DOI: 10.1016/s0167-4781(97)00219-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We report here the cDNA sequence of rat homologue of presenilin-2 (PS-2). The rat PS-2 cDNA encoded 448 amino acids, and the deduced amino acid sequence was highly homologous to those of the human (94.9%), mouse (96.4%) and Xenopus (70.8%). A minor splicing variant lacking a single glutamate was detected, while the product corresponding to the exon 9 deleted splicing variant observed in human was not detected.
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Affiliation(s)
- H Tanahashi
- Division of Demyelinating Disease and Aging, National Institute of Neuroscience, Tokyo, Japan.
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25
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Cruts M, van Duijn CM, Backhovens H, Van den Broeck M, Wehnert A, Serneels S, Sherrington R, Hutton M, Hardy J, St George-Hyslop PH, Hofman A, Van Broeckhoven C. Estimation of the genetic contribution of presenilin-1 and -2 mutations in a population-based study of presenile Alzheimer disease. Hum Mol Genet 1998; 7:43-51. [PMID: 9384602 DOI: 10.1093/hmg/7.1.43] [Citation(s) in RCA: 303] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Two closely related genes, the presenilins ( PS ), located at chromosomes 14q24.3 and 1q42.1, have been identified for autosomal dominant Alzheimer disease (AD) with onset age below 65 years (presenile AD). We performed a systematic mutation analysis of all coding and 5'-non-coding exons of PS -1 and PS -2 in a population-based epidemiological series of 101 unrelated familial and sporadic presenile AD cases. The familial cases included 10 patients of autosomal dominant AD families sampled for linkage analysis studies. In all patients mutations in the amyloid precursor protein gene ( APP ) had previously been excluded. Four different PS -1 missense mutations were identified in six familial cases, two of which where autosomal dominant cases. Three mutations resulted in onset ages above 55 years, with one segregating in an autosomal dominant family with mean onset age 64 years (range 50-78 years). One PS -2 mutation was identified in a sporadic case with onset age 62 years. Our mutation data provided estimates for PS -1 and PS -2 mutation frequencies in presenile AD of 6 and 1% respectively. When family history was accounted for mutation frequencies for PS -1 were 9% in familial cases and 18% in autosomal dominant cases. Further, polymorphisms were detected in the promoter and the 5'-non-coding region of PS -1 and in intronic and exonic sequences of PS -2 that will be useful in genetic association studies.
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Affiliation(s)
- M Cruts
- Laboratory of Neurogenetics, Flanders Interuniversity Institute for Biotechnology (VIB), Born-Bunge Foundation (BBS), University of Antwerp (UIA), Department of Biochemistry, Antwerpen, Belgium
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26
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Marfany G, Del-Favero J, Valero R, De Jonghe C, Woodrow S, Hendriks L, Van Broeckhoven C, Gonzàlez-Duarte R. Identification of a Drosophila presenilin homologue: evidence of alternatively spliced forms. J Neurogenet 1998; 12:41-54. [PMID: 9666900 DOI: 10.3109/01677069809108554] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Some cases of Alzheimer's disease are inherited as a dominant trait in humans. To date, mutations in three genes account for some of them: the amyloid precursor protein (APP) and presenilins 1 and 2 (PS-1 and PS-2, respectively). The function of the presenilins is still unclear, although they belong to a transmembrane protein-gene family, probably involved in some signaling pathway. We report here the isolation of the Drosophila presenilin homologue using the human PS-1 and PS-2 cDNAs as probes. Only one single gene has been detected in the Drosophila genome and evidence for alternatively spliced forms is presented and compared to the isoforms reported in humans. Temporal and spatial expression has been assessed by Northern blot and in situ hybridization on embryos of different developmental stages.
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Affiliation(s)
- G Marfany
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Spain
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27
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Cruts M, Hendriks L, Van Broeckhoven C. The presenilin genes: a new gene family involved in Alzheimer disease pathology. Hum Mol Genet 1996; 5 Spec No:1449-55. [PMID: 8875251 DOI: 10.1093/hmg/5.supplement_1.1449] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A positional cloning approach has led to the identification of two closely related genes, the presenilins (PS), for autosomal dominant presenile Alzheimer disease (AD): PS-1 at 14q24.3 and PS-2 at 1q31-q42. The PS-1 gene was identified by direct cDNA selection of yeast artificial chromosomes containing the candidate chromosomal region. Subsequently, the PS-2 gene was identified due to its high sequence homology with PS-1 and its location within the candidate region defined by linkage studies. To date, 30 different missense mutations and one in-frame splice site mutation were described in PS-1, while only two missense mutations were detected in PS-2, suggesting that PS-1 mutations are more frequently involved in familial presenile AD. The PS transcripts encode novel proteins that resemble integral transmembrane proteins of roughly 450 amino acids and at least seven transmembrane domains. The genomic organization of the PS genes is very similar showing that full length PS-1 and PS-2 are encoded by 10 exons. However, different alternative splicing patterns have been observed for PS-1 and PS-2 indicating that the corresponding proteins (ps-1 and ps-2) may have similar but not identical biological functions.
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Affiliation(s)
- M Cruts
- Laboratory of Neurogenetics, Flanders Interuniversity Institute for Biotechnology (VIB), Antwerpen, Belgium
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