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Malecki C, Hambly BD, Jeremy RW, Robertson EN. The RNA-binding fragile-X mental retardation protein and its role beyond the brain. Biophys Rev 2020; 12:903-916. [PMID: 32654068 DOI: 10.1007/s12551-020-00730-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/06/2020] [Indexed: 12/17/2022] Open
Abstract
It is well-established that variations of a CGG repeat expansion in the gene FMR1, which encodes the fragile-X mental retardation protein (FMRP), cause the neurocognitive disorder, fragile-X syndrome (FXS). However, multiple observations suggest a general and complex regulatory role of FMRP in processes outside the brain: (1) FMRP is ubiquitously expressed in the body, suggesting it functions in multiple organ systems; (2) patients with FXS can exhibit a physical phenotype that is consistent with an underlying abnormality in connective tissue; (3) different CGG repeat expansion lengths in FMR1 result in different clinical outcomes due to different pathogenic mechanisms; (4) the function of FMRP as an RNA-binding protein suggests it has a general regulatory role. This review details the complex nature of FMRP and the different CGG repeat expansion lengths and the evidence supporting the essential role of the protein in a variety of biological and pathological processes.
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Affiliation(s)
- Cassandra Malecki
- Discipline of Pathology and Bosch Institute, The University of Sydney, Level 4 West, Charles Perkins Centre D17, Sydney, NSW, 2006, Australia.
| | - Brett D Hambly
- Discipline of Pathology and Bosch Institute, The University of Sydney, Level 4 West, Charles Perkins Centre D17, Sydney, NSW, 2006, Australia
| | - Richmond W Jeremy
- Discipline of Pathology and Bosch Institute, The University of Sydney, Level 4 West, Charles Perkins Centre D17, Sydney, NSW, 2006, Australia.,Cardiology Department, Royal Prince Alfred Hospital, Sydney, NSW, Australia
| | - Elizabeth N Robertson
- Discipline of Pathology and Bosch Institute, The University of Sydney, Level 4 West, Charles Perkins Centre D17, Sydney, NSW, 2006, Australia.,Cardiology Department, Royal Prince Alfred Hospital, Sydney, NSW, Australia
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Nistal M, Paniagua R, González-Peramato P, Reyes-Múgica M. Perspectives in Pediatric Pathology, Chapter 15. Macrorchidism as the Expression of Several Congenital and Acquired Pathologies. Pediatr Dev Pathol 2016; 19:202-18. [PMID: 25105801 DOI: 10.2350/14-05-1494-pb.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Manuel Nistal
- 1 Department of Pathology, Hospital La Paz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Ricardo Paniagua
- 2 Department of Cell Biology, Universidad de Alcala, Madrid, Spain
| | | | - Miguel Reyes-Múgica
- 3 Department of Pathology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
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Nistal M, Paniagua R, González-Peramato P, Reyes-Múgica M. Perspectives in pediatric pathology, chapter 3. Testicular development from birth to puberty: systematic evaluation of the prepubertal testis. Pediatr Dev Pathol 2015; 18:173-86. [PMID: 25075859 DOI: 10.2350/12-09-1255-pb.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Manuel Nistal
- Department of Pathology, Hospital La Paz, Universidad Autónoma de Madrid, Calle Arzobispo Morcillo #2, Madrid 28029, Spain
| | - Ricardo Paniagua
- Department of Cell Biology, Universidad de Alcala, Madrid, Spain
| | - Pilar González-Peramato
- Department of Pathology, Hospital La Paz, Universidad Autónoma de Madrid, Calle Arzobispo Morcillo #2, Madrid 28029, Spain
| | - Miguel Reyes-Múgica
- Department of Pathology, Children's Hospital of Pittsburgh of UPMC, One Children's Hospital Drive, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
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Coffee RL, Tessier CR, Woodruff EA, Broadie K. Fragile X mental retardation protein has a unique, evolutionarily conserved neuronal function not shared with FXR1P or FXR2P. Dis Model Mech 2010; 3:471-85. [PMID: 20442204 DOI: 10.1242/dmm.004598] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Fragile X syndrome (FXS), resulting solely from the loss of function of the human fragile X mental retardation 1 (hFMR1) gene, is the most common heritable cause of mental retardation and autism disorders, with syndromic defects also in non-neuronal tissues. In addition, the human genome encodes two closely related hFMR1 paralogs: hFXR1 and hFXR2. The Drosophila genome, by contrast, encodes a single dFMR1 gene with close sequence homology to all three human genes. Drosophila that lack the dFMR1 gene (dfmr1 null mutants) recapitulate FXS-associated molecular, cellular and behavioral phenotypes, suggesting that FMR1 function has been conserved, albeit with specific functions possibly sub-served by the expanded human gene family. To test evolutionary conservation, we used tissue-targeted transgenic expression of all three human genes in the Drosophila disease model to investigate function at (1) molecular, (2) neuronal and (3) non-neuronal levels. In neurons, dfmr1 null mutants exhibit elevated protein levels that alter the central brain and neuromuscular junction (NMJ) synaptic architecture, including an increase in synapse area, branching and bouton numbers. Importantly, hFMR1 can, comparably to dFMR1, fully rescue both the molecular and cellular defects in neurons, whereas hFXR1 and hFXR2 provide absolutely no rescue. For non-neuronal requirements, we assayed male fecundity and testes function. dfmr1 null mutants are effectively sterile owing to disruption of the 9+2 microtubule organization in the sperm tail. Importantly, all three human genes fully and equally rescue mutant fecundity and spermatogenesis defects. These results indicate that FMR1 gene function is evolutionarily conserved in neural mechanisms and cannot be compensated by either FXR1 or FXR2, but that all three proteins can substitute for each other in non-neuronal requirements. We conclude that FMR1 has a neural-specific function that is distinct from its paralogs, and that the unique FMR1 function is responsible for regulating neuronal protein expression and synaptic connectivity.
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Affiliation(s)
- R Lane Coffee
- Department of Biological Sciences, Vanderbilt Brain Institute, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235-1634, USA
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Georgiou I, Syrrou M, Pardalidis N, Karakitsios K, Mantzavinos T, Giotitsas N, Loutradis D, Dimitriadis F, Saito M, Miyagawa I, Tzoumis P, Sylakos A, Kanakas N, Moustakareas T, Baltogiannis D, Touloupides S, Giannakis D, Fatouros M, Sofikitis N. Genetic and epigenetic risks of intracytoplasmic sperm injection method. Asian J Androl 2007; 8:643-73. [PMID: 17111067 DOI: 10.1111/j.1745-7262.2006.00231.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Pregnancies achieved by assisted reproduction technologies, particularly by intracytoplasmic sperm injection (ICSI) procedures, are susceptible to genetic risks inherent to the male population treated with ICSI and additional risks inherent to this innovative procedure. The documented, as well as the theoretical, risks are discussed in the present review study. These risks mainly represent that consequences of the genetic abnormalities underlying male subfertility (or infertility) and might become stimulators for the development of novel approaches and applications in the treatment of infertility. In addition, risks with a polygenic background appearing at birth as congenital anomalies and other theoretical or stochastic risks are discussed. Recent data suggest that assisted reproductive technology might also affect epigenetic characteristics of the male gamete, the female gamete, or might have an impact on early embryogenesis. It might be also associated with an increased risk for genomic imprinting abnormalities.
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Affiliation(s)
- Ioannis Georgiou
- Laboratory of Molecular Urology and Genetics of Human Reproduction, Department of Urology, Ioannina University School of Medicine, Ioannina 45110, Greece
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Abstract
Biopsy of the testis is not universally accepted in contrast with biopsies of other organs. The pathologist studies and reports on the pathophysiology of the testicular biopsy specimen. Methodology requires the inclusion of qualitative and quantitative studies, the evaluation of the lesion's evolution (prognosis), and, often, therapeutic advice regarding treatment. Cooperation between pathologists and clinicians optimizes the utility of the biopsy for the patient.
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Affiliation(s)
- M Nistal
- Department of Pathology, La Paz Hospital, Madrid, Spain
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Abstract
The fragile X syndrome is characterised by mental retardation, behavioural features, and physical features, such as a long face with large protruding ears and macro-orchidism. In 1991, after identification of the fragile X mental retardation (FMR1) gene, the cytogenetic marker (a fragile site at Xq27.3) became replaced by molecular diagnosis. The fragile X syndrome was one of the first examples of a "novel" class of disorders caused by a trinucleotide repeat expansion. In the normal population, the CGG repeat varies from six to 54 units. Affected subjects have expanded CGG repeats (>200) in the first exon of the FMR1 gene (the full mutation). Phenotypically normal carriers of the fragile X syndrome have a repeat in the 43 to 200 range (the premutation). The cloning of the FMR1 gene led to the characterisation of its protein product FMRP, encouraged further clinical studies, and opened up the possibility of more accurate family studies and fragile X screening programmes.
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Affiliation(s)
- B B de Vries
- Department of Clinical Genetics, University Hospital Dijkzigt and Erasmus University, Rotterdam, The Netherlands
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Slegtenhorst-Eegdeman KE, de Rooij DG, Verhoef-Post M, van de Kant HJ, Bakker CE, Oostra BA, Grootegoed JA, Themmen AP. Macroorchidism in FMR1 knockout mice is caused by increased Sertoli cell proliferation during testicular development. Endocrinology 1998; 139:156-62. [PMID: 9421410 DOI: 10.1210/endo.139.1.5706] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The fragile X syndrome is the most frequent hereditary form of mental retardation. This X-linked disorder is, in most cases, caused by an unstable and expanding trinucleotide CGG repeat located in the 5'-untranslated region of the gene involved, the fragile X mental retardation 1 (FMR1) gene. Expansion of the CGG repeat to a length of more than 200 trinucleotides results in silencing of the FMR1 gene promoter and, thus, in an inactive gene. The clinical features of male fragile X patients include mental retardation, autistiform behavior, and characteristic facial features. In addition, macroorchidism is observed. To study the role of Sertoli cell proliferation and FSH signal transduction in the occurrence of macroorchidism in fragile X males, we made use of an animal model for the fragile X syndrome, an Fmr1 knockout mouse. The results indicate that in male Fmr1 knockout mice, the rate of Sertoli cell proliferation is increased from embryonic day 12 to 15 days postnatally. The onset and length of the period of Sertoli cell proliferation were not changed compared with those in the control males. Serum levels of FSH, FSH receptor messenger RNA expression, and short term effects of FSH on Sertoli cell function, as measured by down-regulation of FSH receptor messenger RNA, were not changed. We conclude that macroorchidism in Fmr1 knockout male mice is caused by an increased rate of Sertoli cell proliferation. This increase does not appear to be the result of a major change in FSH signal transduction in Fmr1 knockout mice.
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Affiliation(s)
- K E Slegtenhorst-Eegdeman
- Department of Endocrinology, Faculty of Health and Health Sciences, Erasmus University Rotterdam, The Netherlands
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Nistal M, Martínez-García F, Regadera J, Cobo P, Paniagua R. Macro-orchidism: a clinicopathological approach. J Urol 1994; 151:1155-61. [PMID: 8158750 DOI: 10.1016/s0022-5347(17)35203-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- M Nistal
- Department of Morphology, School of Medicine, Autonomous University of Madrid, Spain
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