1
|
Cesari E, Farini D, Medici V, Ehrmann I, Guerra M, Testa E, Naro C, Geloso MC, Pagliarini V, La Barbera L, D’Amelio M, Orsini T, Vecchioli SF, Tamagnone L, Fort P, Viscomi MT, Elliott DJ, Sette C. Differential expression of paralog RNA binding proteins establishes a dynamic splicing program required for normal cerebral cortex development. Nucleic Acids Res 2024; 52:4167-4184. [PMID: 38324473 PMCID: PMC11077083 DOI: 10.1093/nar/gkae071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 01/17/2024] [Accepted: 01/25/2024] [Indexed: 02/09/2024] Open
Abstract
Sam68 and SLM2 are paralog RNA binding proteins (RBPs) expressed in the cerebral cortex and display similar splicing activities. However, their relative functions during cortical development are unknown. We found that these RBPs exhibit an opposite expression pattern during development. Sam68 expression declines postnatally while SLM2 increases after birth, and this developmental pattern is reinforced by hierarchical control of Sam68 expression by SLM2. Analysis of Sam68:Slm2 double knockout (Sam68:Slm2dko) mice revealed hundreds of exons that respond to joint depletion of these proteins. Moreover, parallel analysis of single and double knockout cortices indicated that exons regulated mainly by SLM2 are characterized by a dynamic splicing pattern during development, whereas Sam68-dependent exons are spliced at relatively constant rates. Dynamic splicing of SLM2-sensitive exons is completely suppressed in the Sam68:Slm2dko developing cortex. Sam68:Slm2dko mice die perinatally with defects in neurogenesis and in neuronal differentiation, and develop a hydrocephalus, consistent with splicing alterations in genes related to these biological processes. Thus, our study reveals that developmental control of separate Sam68 and Slm2 paralog genes encoding homologous RBPs enables the orchestration of a dynamic splicing program needed for brain development and viability, while ensuring a robust redundant mechanism that supports proper cortical development.
Collapse
Affiliation(s)
- Eleonora Cesari
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
| | - Donatella Farini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
- Fondazione Santa Lucia IRCCS, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
| | - Vanessa Medici
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Ingrid Ehrmann
- Newcastle University Centre for Cancer, Newcastle University Institute of Biosciences, Newcastle NE1 3BZ, UK
| | - Marika Guerra
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Erika Testa
- Department of Life Science and Public Health, Section of Histology and Embryology, Catholic University of the Sacred Heart, Rome
| | - Chiara Naro
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
| | - Maria Concetta Geloso
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
| | - Livia La Barbera
- Fondazione Santa Lucia IRCCS, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
| | - Marcello D’Amelio
- Fondazione Santa Lucia IRCCS, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
- Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 21, 00128 Rome, Italy
| | - Tiziana Orsini
- Institute of Biochemistry and Cell Biology, National Research Council (IBBC/CNR), Monterotondo, 00015 Rome, Italy
| | - Stefano Farioli Vecchioli
- Institute of Biochemistry and Cell Biology, National Research Council (IBBC/CNR), Monterotondo, 00015 Rome, Italy
| | - Luca Tamagnone
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
- Department of Life Science and Public Health, Section of Histology and Embryology, Catholic University of the Sacred Heart, Rome
| | - Philippe Fort
- Centre de Recherche en Biologie Cellulaire de Montpellier, University of Montpellier, CNRS, 1919 Route de Mende, 34293 Montpellier Cedex 05, France
| | - Maria Teresa Viscomi
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
- Department of Life Science and Public Health, Section of Histology and Embryology, Catholic University of the Sacred Heart, Rome
| | - David J Elliott
- Newcastle University Centre for Cancer, Newcastle University Institute of Biosciences, Newcastle NE1 3BZ, UK
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
| |
Collapse
|
2
|
Verdile V, Palombo R, Ferrante G, Ferri A, Amadio S, Volonté C, Paronetto MP. Dysregulation of alternative splicing underlies synaptic defects in familial amyotrophic lateral sclerosis. Prog Neurobiol 2023; 231:102529. [PMID: 37739207 DOI: 10.1016/j.pneurobio.2023.102529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 09/11/2023] [Accepted: 09/17/2023] [Indexed: 09/24/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease characterized by the degeneration of upper and lower motor neurons, progressive wasting and paralysis of voluntary muscles. A hallmark of ALS is the frequent nuclear loss and cytoplasmic accumulation of RNA binding proteins (RBPs) in motor neurons (MN), which leads to aberrant alternative splicing regulation. However, whether altered splicing patterns are also present in familial models of ALS without mutations in RBP-encoding genes has not been investigated yet. Herein, we found that altered splicing of synaptic genes is a common trait of familial ALS MNs. Similar deregulation was also observed in hSOD1G93A MN-like cells. In silico analysis identified the potential regulators of these pre-mRNAs, including the RBP Sam68. Immunofluorescence analysis and biochemical fractionation experiments revealed that Sam68 accumulates in the cytoplasmic insoluble ribonucleoprotein fraction of MN. Remarkably, the synaptic splicing events deregulated in ALS MNs were also affected in Sam68-/- spinal cords. Recombinant expression of Sam68 protein was sufficient to rescue these splicing changes in ALS hSOD1G93A MN-like cells. Hence, our study highlights an aberrant function of Sam68, which leads to splicing changes in synaptic genes and may contribute to the MN phenotype that characterizes ALS.
Collapse
Affiliation(s)
- Veronica Verdile
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135 Rome, Italy; Division of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, Rome 00143, Italy
| | - Ramona Palombo
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135 Rome, Italy
| | - Gabriele Ferrante
- Division of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, Rome 00143, Italy
| | - Alberto Ferri
- Division of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, Rome 00143, Italy; National Research Council (CNR), Institute of Translational Pharmacology (IFT), Rome, Italy
| | - Susanna Amadio
- Division of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, Rome 00143, Italy
| | - Cinzia Volonté
- Division of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, Rome 00143, Italy; National Research Council (CNR), Institute for Systems Analysis and Computer Science (IASI), Rome, Italy
| | - Maria Paola Paronetto
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135 Rome, Italy; Division of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, Rome 00143, Italy.
| |
Collapse
|
3
|
Boustanai I, Raanani H, Aizer A, Orvieto R, Elizur SE. Granulosa Cell Dysfunction Is Associated With Diminished Ovarian Response in FMR1 Premutation Carriers. J Clin Endocrinol Metab 2022; 107:3000-3009. [PMID: 36112470 DOI: 10.1210/clinem/dgac536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Indexed: 02/13/2023]
Abstract
CONTEXT FMR1 premutation (PM) carriers are at increased risk of ovarian impairment resulting in diminished ovarian response (DOR) to exogenous follicle-stimulating hormone (FSH) stimulation. Expanded CGG repeat transcript and RAN-associated protein (FMRpolyG) have been shown to accumulate in cellular aggregates and sequester proteins, thus impairing their function. Sam68 is a multifunctional RNA-binding protein highly expressed in the gonads involved in FSH receptor (FSHR) transcript maturation during FSH-dependent follicular development. OBJECTIVE The present study examined a possible pathophysiological explanation for DOR to exogenous FSH stimulation in FMR1 PM carriers. METHODS We used both a human granulosa cell (GC) line model and human GCs from FMR1 PM carriers to evaluate whether Sam68 is sequestered with expanded CGG repeat transcript. RESULTS We show that Sam68 is sequestered in GCs, most likely by interaction with the expanded CGG repeat transcript. The sequestration may lead to reduced levels of free Sam68 available for FHSR precursor transcript processing, causing dysregulation of FSHR transcript maturation, and a consequent decrease in FSHR protein levels. CONCLUSION Sam68 sequestration may underlie the diminished ovarian response to FSH stimulation in FMR1 PM carriers.
Collapse
Affiliation(s)
- Ilana Boustanai
- Sheba Medical Center Hospital-Tel Hashomer, Ramat-Gan 52621, Israel
| | - Hila Raanani
- Sheba Medical Center Hospital-Tel Hashomer, Ramat-Gan 52621, Israel
| | - Adva Aizer
- Sheba Medical Center Hospital-Tel Hashomer, Ramat-Gan 52621, Israel
| | - Raoul Orvieto
- Sheba Medical Center Hospital-Tel Hashomer, Ramat-Gan 52621, Israel
- Sackler Faculty of Medicine Tel-Aviv University, Tel-Aviv 6997801, Israel
| | - Shai E Elizur
- Sheba Medical Center Hospital-Tel Hashomer, Ramat-Gan 52621, Israel
- Sackler Faculty of Medicine Tel-Aviv University, Tel-Aviv 6997801, Israel
| |
Collapse
|
4
|
Vilariño-García T, Guadix P, Dorado-Silva M, Sánchez-Martín P, Pérez-Pérez A, Sánchez-Margalet V. Decreased Expression of Sam68 Is Associated with Insulin Resistance in Granulosa Cells from PCOS Patients. Cells 2022; 11:cells11182821. [PMID: 36139396 PMCID: PMC9496917 DOI: 10.3390/cells11182821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND AND OBJECTIVE Polycystic ovary syndrome (PCOS) is a complex metabolic disorder associated with ovulatory dysfunction, hyperandrogenism, obesity, and insulin resistance, which leads to subfertility. PCOS is the most frequent metabolic disorder in women and the major cause of infertility. Susceptibility to developing PCOS is determined by a complex interaction between environmental and genetic factors. Although different mechanisms have been proposed to explain PCOS manifestations, defects in insulin actions or in the insulin signaling pathways are central in the pathogenesis of the syndrome. However, the mechanisms (molecular players and signaling pathways) underlying its primary origin still remain an unsolved issue. Current research is increasingly focusing on the discovery of novel biomarkers to further elucidate the complex pathophysiology of PCOS. Sam68, an RNA-binding protein, is recruited to insulin signaling, mediating different insulin actions. We aimed to investigate the role of Sam68 in insulin signaling and the possible implications of Sam68 in the insulin resistance in PCOS. MATERIALS AND METHODS Granulosa cells were taken from women with PCOS (n = 25) and healthy donors (n = 25) and, within the age range of 20 to 42 years, from GINEMED, Assisted Reproduction Centre, Seville, Spain. The Sam68 expression level was analyzed both by qPCR and immunoblot. Statistical significance was assessed by one-way ANOVA, followed by a post-hoc test. A p value of < 0.05 was considered statistically significant. RESULTS We found that insulin stimulation increases the phosphorylation and expression level of Sam68 in granulosa cells from normal donors. The downregulation of Sam68 expression resulted in a lower activation of both the MAPK and the PI3K pathways in response to insulin. Moreover, the granulosa cells from the women with PCOS presented a lower expression of Sam68, as well as insulin receptor and insulin receptor substrate-1 (IRS-1). In these cells, the overexpression of Sam68 resulted in an increased activation of both the MAPK and the PI3K pathways in response to insulin. CONCLUSIONS These results suggest the participation of Sam68 in insulin receptor signaling, mediating the insulin effect in granulosa cells, and they suggest the possible role of Sam68 in the insulin resistance of PCOS.
Collapse
Affiliation(s)
- Teresa Vilariño-García
- Department of Medical Biochemistry and Molecular Biology and Immunology, Virgen Macarena University Hospital, School of Medicine, University of Seville, 41009 Seville, Spain
| | - Pilar Guadix
- Obstetrics and Gynecology Department, Virgen Macarena University Hospital, School of Medicine, University of Seville, 41009 Seville, Spain
| | | | | | - Antonio Pérez-Pérez
- Department of Medical Biochemistry and Molecular Biology and Immunology, Virgen Macarena University Hospital, School of Medicine, University of Seville, 41009 Seville, Spain
- Correspondence: (A.P.-P.); (V.S.-M.); Tel.: +95-4559-850 (A.P.-P.)
| | - Víctor Sánchez-Margalet
- Department of Medical Biochemistry and Molecular Biology and Immunology, Virgen Macarena University Hospital, School of Medicine, University of Seville, 41009 Seville, Spain
- Correspondence: (A.P.-P.); (V.S.-M.); Tel.: +95-4559-850 (A.P.-P.)
| |
Collapse
|
5
|
Rosario R, Anderson R. The molecular mechanisms that underlie fragile X-associated premature ovarian insufficiency: is it RNA or protein based? Mol Hum Reprod 2021; 26:727-737. [PMID: 32777047 PMCID: PMC7566375 DOI: 10.1093/molehr/gaaa057] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/03/2020] [Indexed: 01/30/2023] Open
Abstract
The FMR1 gene contains a polymorphic CGG trinucleotide sequence within its 5′ untranslated region. More than 200 CGG repeats (termed a full mutation) underlie the severe neurodevelopmental condition fragile X syndrome, while repeat lengths that range between 55 and 200 (termed a premutation) result in the conditions fragile X-associated tremor/ataxia syndrome and fragile X-associated premature ovarian insufficiency (FXPOI). Premutations in FMR1 are the most common monogenic cause of premature ovarian insufficiency and are routinely tested for clinically; however, the mechanisms that contribute to the pathology are still largely unclear. As studies in this field move towards unravelling the molecular mechanisms involved in FXPOI aetiology, we review the evidence surrounding the two main theories which describe an RNA toxic gain-of-function mechanism, resulting in the loss of function of RNA-binding proteins, or a protein-based mechanism, where repeat-associated non-AUG translation leads to the formation of an abnormal polyglycine containing protein, called FMRpolyG.
Collapse
Affiliation(s)
- Roseanne Rosario
- MRC Centre for Reproductive Health, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Richard Anderson
- MRC Centre for Reproductive Health, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
6
|
Yang Q, Mumusoglu S, Qin Y, Sun Y, Hsueh AJ. A kaleidoscopic view of ovarian genes associated with premature ovarian insufficiency and senescence. FASEB J 2021; 35:e21753. [PMID: 34233068 DOI: 10.1096/fj.202100756r] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/04/2021] [Accepted: 06/08/2021] [Indexed: 12/14/2022]
Abstract
Ovarian infertility and subfertility presenting with premature ovarian insufficiency (POI) and diminished ovarian reserve are major issues facing the developed world due to the trend of delaying childbirth. Ovarian senescence and POI represent a continuum of physiological/pathophysiological changes in ovarian follicle functions. Based on advances in whole exome sequencing, evaluation of gene copy variants, together with family-based and genome-wide association studies, we discussed genes responsible for POI and ovarian senescence. We used a gene-centric approach to sort out literature deposited in the Ovarian Kaleidoscope database (http://okdb.appliedbioinfo.net) by sub-categorizing candidate genes as ligand-receptor signaling, meiosis and DNA repair, transcriptional factors, RNA metabolism, enzymes, and others. We discussed individual gene mutations found in POI patients and verification of gene functions in gene-deleted model organisms. Decreased expression of some of the POI genes could be responsible for ovarian senescence, especially those essential for DNA repair, meiosis and mitochondrial functions. We propose to set up a candidate gene panel for targeted sequencing in POI patients together with studies on mitochondria-associated genes in middle-aged subfertile patients.
Collapse
Affiliation(s)
- Qingling Yang
- Center for Reproductive Medicine, Henan Key Laboratory of Reproduction and Genetics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA, USA
| | - Sezcan Mumusoglu
- Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Obstetrics and Gynecology, Hacettepe University School of Medicine, Ankara, Turkey
| | - Yingying Qin
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yingpu Sun
- Center for Reproductive Medicine, Henan Key Laboratory of Reproduction and Genetics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Aaron J Hsueh
- Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA, USA
| |
Collapse
|
7
|
Dysregulation of anti-Mullerian hormone expression levels in mural granulosa cells of FMR1 premutation carriers. Sci Rep 2021; 11:14139. [PMID: 34238973 PMCID: PMC8266831 DOI: 10.1038/s41598-021-93489-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 06/04/2021] [Indexed: 12/26/2022] Open
Abstract
FMR1 premutation (55–200 CGG repeats) results in fragile X-associated primary ovarian insufficiency (FXPOI). We evaluated expression levels of folliculogenesis-related mediators, follicle-stimulating hormone (FSH) receptor and anti-Mullerian hormone (AMH), to gain insights into the mechanisms underlying the reduced ovarian function. Mural granulosa cells (MGCs) were collected from FMR1 premutation carriers and noncarriers undergoing IVF treatments. At baseline, MGCs of carriers demonstrated significantly higher mRNA expression levels of AMH (3.5 ± 2.2, n = 12 and 0.97 ± 0.5, n = 17, respectively; p = 0.0003) and FSH receptor (5.6 ± 2.8 and 2.7 ± 2.8, respectively; p = 0.02) and higher AMH protein expression on immunostaining. Accordingly, FMR1 premutation-transfected COV434 cells exhibited higher AMH protein expression than COV434 cells transfected with 20 CGG repeats. We conclude that FMR1 premutation may lead to dysregulation of AMH expression levels, probably due to a compensatory mechanism. Elucidating the pathophysiology of FXPOI may help in early detection of ovarian dysfunction and tailoring IVF treatments to FMR1 premutation carriers.
Collapse
|
8
|
De Paola E, Forcina L, Pelosi L, Pisu S, La Rosa P, Cesari E, Nicoletti C, Madaro L, Mercatelli N, Biamonte F, Nobili A, D'Amelio M, De Bardi M, Volpe E, Caporossi D, Sette C, Musarò A, Paronetto MP. Sam68 splicing regulation contributes to motor unit establishment in the postnatal skeletal muscle. Life Sci Alliance 2020; 3:3/10/e201900637. [PMID: 32753528 PMCID: PMC7409371 DOI: 10.26508/lsa.201900637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 01/08/2023] Open
Abstract
Sam68 ensures the establishment of neuromuscular junctions (NMJs) and motor unit integrity by orchestrating a neuronal splicing program. RNA-binding proteins orchestrate the composite life of RNA molecules and impact most physiological processes, thus underlying complex phenotypes. The RNA-binding protein Sam68 regulates differentiation processes by modulating splicing, polyadenylation, and stability of select transcripts. Herein, we found that Sam68−/− mice display altered regulation of alternative splicing in the spinal cord of key target genes involved in synaptic functions. Analysis of the motor units revealed that Sam68 ablation impairs the establishment of neuromuscular junctions and causes progressive loss of motor neurons in the spinal cord. Importantly, alterations of neuromuscular junction morphology and properties in Sam68−/− mice correlate with defects in muscle and motor unit integrity. Sam68−/− muscles display defects in postnatal development, with manifest signs of atrophy. Furthermore, fast-twitch muscles in Sam68−/− mice show structural features typical of slow-twitch muscles, suggesting alterations in the metabolic and functional properties of myofibers. Collectively, our data identify a key role for Sam68 in muscle development and suggest that proper establishment of motor units requires timely expression of synaptic splice variants.
Collapse
Affiliation(s)
- Elisa De Paola
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy.,IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy
| | - Laura Forcina
- Laboratory Affiliated to Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Laura Pelosi
- Laboratory Affiliated to Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Simona Pisu
- Laboratory Affiliated to Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Piergiorgio La Rosa
- IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy
| | - Eleonora Cesari
- IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy.,Institute of Human Anatomy and Cell Biology, Catholic University of the Sacred Heart, Rome, Italy
| | - Carmine Nicoletti
- Laboratory Affiliated to Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Luca Madaro
- Institute of Human Anatomy and Cell Biology, Catholic University of the Sacred Heart, Rome, Italy
| | - Neri Mercatelli
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy.,IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy
| | - Filippo Biamonte
- Institute of Biochemistry and Clinical Biochemistry, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Annalisa Nobili
- IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy.,Department of Medicine, University Campus-Biomedico, Rome, Italy
| | - Marcello D'Amelio
- IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy.,Department of Medicine, University Campus-Biomedico, Rome, Italy
| | - Marco De Bardi
- IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy
| | - Elisabetta Volpe
- IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy
| | - Daniela Caporossi
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy
| | - Claudio Sette
- IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy .,Institute of Human Anatomy and Cell Biology, Catholic University of the Sacred Heart, Rome, Italy
| | - Antonio Musarò
- Laboratory Affiliated to Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Maria Paola Paronetto
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy .,IRCCS (Institute for Treatment and Research) Fondazione Santa Lucia, Rome, Italy
| |
Collapse
|
9
|
Vilariño-García T, Pérez-Pérez A, Santamaría-López E, Prados N, Fernández-Sánchez M, Sánchez-Margalet V. Sam68 mediates leptin signaling and action in human granulosa cells: possible role in leptin resistance in PCOS. Endocr Connect 2020; 9:479-488. [PMID: 32375121 PMCID: PMC7354740 DOI: 10.1530/ec-20-0062] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Polycystic ovary syndrome (PCOS) is a complex metabolic disorder associated with ovulatory dysfunction, hyperandrogenism, obesity, and insulin resistance, that leads to subfertility. Sam68 is an RNA-binding protein with signaling functions that is ubiquitously expressed, including gonads. Sam68 is recruited to leptin signaling, mediating different leptin actions. OBJECTIVE We aimed to investigate the role of Sam68 in leptin signaling, mediating the effect on aromatase expression in granulosa cells and the posible implication of Sam68 in the leptin resistance in PCOS. MATERIALS AND METHODS Granulosa cells were from healthy donors (n = 25) and women with PCOS (n = 25), within the age range of 20 to 40 years, from Valencian Infertility Institute (IVI), Seville, Spain. Sam68 expression was inhibited by siRNA method and overexpressed by expression vector. Expression level was analysed by qPCR and immunoblot. Statistical significance was assessed by ANOVA followed by different post-hoc tests. A P value of <0.05 was considered statistically significant. RESULTS We have found that leptin stimulation increases phosphorylation and expression level of Sam68 and aromatase in granulosa cells from normal donors. Downregulation of Sam68 expression resulted in a lower activation of MAPK and PI3K pathways in response to leptin, whereas overexpression of Sam68 increased leptin stimulation of signaling, enhancing aromatase expression. Granulosa cells from women with PCOS presented lower expression of Sam68 and were resistant to the leptin effect on aromatase expression. CONCLUSIONS These results suggest the participation of Sam68 in leptin receptor signaling, mediating the leptin effect on aromatase expression in granulosa cells, and point to a new target in leptin resistance in PCOS.
Collapse
Affiliation(s)
- Teresa Vilariño-García
- Department of Medical Biochemistry, Molecular Biology and Immunology. Medical School, Virgen Macarena University Hospital, University of Seville, Seville, Spain
| | - Antonio Pérez-Pérez
- Department of Medical Biochemistry, Molecular Biology and Immunology. Medical School, Virgen Macarena University Hospital, University of Seville, Seville, Spain
| | | | | | | | - Víctor Sánchez-Margalet
- Department of Medical Biochemistry, Molecular Biology and Immunology. Medical School, Virgen Macarena University Hospital, University of Seville, Seville, Spain
- Correspondence should be addressed to V Sánchez-Margalet:
| |
Collapse
|
10
|
França MM, Mendonca BB. Genetics of Primary Ovarian Insufficiency in the Next-Generation Sequencing Era. J Endocr Soc 2020; 4:bvz037. [PMID: 32099950 PMCID: PMC7033037 DOI: 10.1210/jendso/bvz037] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 12/17/2019] [Indexed: 01/12/2023] Open
Abstract
Primary ovarian insufficiency (POI) is characterized by amenorrhea, increased follicle-stimulating hormone (FSH) levels, and hypoestrogenism, leading to infertility before the age of 40 years. Elucidating the cause of POI is a key point for diagnosing and treating affected women. Here, we review the genetic etiology of POI, highlighting new genes identified in the last few years using next-generation sequencing (NGS) approaches. We searched the MEDLINE/PubMed, Cochrane, and Web of Science databases for articles published in or translated to English. Several genes were found to be associated with POI genetic etiology in humans and animal models (SPIDR, BMPR2, MSH4, MSH5, GJA4, FANCM, POLR2C, MRPS22, KHDRBS1, BNC1, WDR62, ATG7/ATG9, BRCA2, NOTCH2, POLR3H, and TP63). The heterogeneity of POI etiology has been revealed to be remarkable in the NGS era, and discoveries have indicated that meiosis and DNA repair play key roles in POI development.
Collapse
Affiliation(s)
- Monica Malheiros França
- Unidade de Endocrinologia do Desenvolvimento, Laboratório de Hormônios e Genética Molecular/LIM42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Berenice Bilharinho Mendonca
- Unidade de Endocrinologia do Desenvolvimento, Laboratório de Hormônios e Genética Molecular/LIM42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| |
Collapse
|
11
|
Jiao X, Ke H, Qin Y, Chen ZJ. Molecular Genetics of Premature Ovarian Insufficiency. Trends Endocrinol Metab 2018; 29:795-807. [PMID: 30078697 DOI: 10.1016/j.tem.2018.07.002] [Citation(s) in RCA: 155] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 07/06/2018] [Accepted: 07/10/2018] [Indexed: 12/31/2022]
Abstract
Premature ovarian insufficiency (POI) is highly heterogeneous in genetic etiology. Yet identifying causative genes has been challenging with candidate gene approaches. Recent approaches using next generation sequencing (NGS), especially whole exome sequencing (WES), in large POI pedigrees have identified new causatives and proposed relevant candidates, mainly enriched in DNA damage repair, homologous recombination, and meiosis. In the near future, NGS or whole genome sequencing will help better define genes involved in intricate regulatory networks. The research into miRNA and age at menopause represents an emerging field that will help unveil the molecular mechanisms underlying pathogenesis of POI. Shedding light on the genetic architecture is important in interpreting pathogenesis of POI, and will facilitate risk prediction for POI.
Collapse
Affiliation(s)
- Xue Jiao
- Center for Reproductive Medicine, Shandong University, Jinan 250021, Shandong, China; National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Jinan 250021, Shandong, China; The Key Laboratory of Reproductive Endocrinology (Shandong University), Ministry of Education, Jinan 250021, Shandong, China; Suzhou Institute of Shandong University, Suzhou 215123, Jiangsu, China
| | - Hanni Ke
- Center for Reproductive Medicine, Shandong University, Jinan 250021, Shandong, China; National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Jinan 250021, Shandong, China; The Key Laboratory of Reproductive Endocrinology (Shandong University), Ministry of Education, Jinan 250021, Shandong, China
| | - Yingying Qin
- Center for Reproductive Medicine, Shandong University, Jinan 250021, Shandong, China; National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Jinan 250021, Shandong, China; The Key Laboratory of Reproductive Endocrinology (Shandong University), Ministry of Education, Jinan 250021, Shandong, China.
| | - Zi-Jiang Chen
- Center for Reproductive Medicine, Shandong University, Jinan 250021, Shandong, China; National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Jinan 250021, Shandong, China; The Key Laboratory of Reproductive Endocrinology (Shandong University), Ministry of Education, Jinan 250021, Shandong, China; Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China; Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai 200127, China.
| |
Collapse
|
12
|
The RNA binding protein Sam68 controls T helper 1 differentiation and anti-mycobacterial response through modulation of miR-29. Cell Death Differ 2018; 26:1169-1180. [PMID: 30258098 DOI: 10.1038/s41418-018-0201-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 08/08/2018] [Accepted: 08/27/2018] [Indexed: 12/24/2022] Open
Abstract
Polarization of naive T cells into interferon (IFN)-γ-producing T helper 1 (Th1) cells is an essential event in the inflammatory response to pathogens. Herein, we identify the RNA binding protein Sam68 as a specific modulator of Th1 differentiation. Sam68-knockout (ko) naive T cells are strongly defective in IL-12-mediated Th1 polarization and express low levels of T-bet and Eomes. Consequently, Sam68-ko Th1 cells are significantly impaired in IFN-γ production. Moreover, we found that Sam68 is required for the induction of an inflammatory Th1 response during Mycobacterium bovis Bacillus Calmette-Guerin (BCG) infection, thus limiting bacterial dissemination in the lungs. Mechanistically, Sam68 directly binds to the microRNA miR-29, a negative regulator of Th1 response, and inhibits its expression during BCG infection. These findings uncover a novel post-transcriptional mechanism required for the Th1-mediated defense against intracellular pathogens and identify a new function for Sam68 in the regulation of the immune response.
Collapse
|
13
|
Carlosama C, Patiño LC, Beau I, Morel A, Delemer B, Young J, Binart N, Laissue P. A novel mutation in KHDRBS1 in a patient affected by primary ovarian insufficiency. Clin Endocrinol (Oxf) 2018; 89:245-246. [PMID: 29808484 DOI: 10.1111/cen.13749] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Carolina Carlosama
- Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, GENIUROS Research Group, Universidad del Rosario, Bogotá, Colombia
| | - Liliana Catherine Patiño
- Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, GENIUROS Research Group, Universidad del Rosario, Bogotá, Colombia
| | - Isabelle Beau
- Inserm 1185, Faculté de Médecine Paris Sud, Le Kremlin-Bicêtre, Université Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Adrien Morel
- Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, GENIUROS Research Group, Universidad del Rosario, Bogotá, Colombia
| | - Brigitte Delemer
- Service d'Endocrinologie-Diabète-Nutrition, CHU de Reims-Hôpital Robert-Debré, Reims, France
| | - Jacques Young
- Inserm 1185, Faculté de Médecine Paris Sud, Le Kremlin-Bicêtre, Université Paris-Saclay, Le Kremlin-Bicêtre, France
- Service d'Endocrinologie et des Maladies de la Reproduction, APHP, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France
| | - Nadine Binart
- Inserm 1185, Faculté de Médecine Paris Sud, Le Kremlin-Bicêtre, Université Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Paul Laissue
- Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, GENIUROS Research Group, Universidad del Rosario, Bogotá, Colombia
| |
Collapse
|
14
|
Man L, Lekovich J, Rosenwaks Z, Gerhardt J. Fragile X-Associated Diminished Ovarian Reserve and Primary Ovarian Insufficiency from Molecular Mechanisms to Clinical Manifestations. Front Mol Neurosci 2017; 10:290. [PMID: 28955201 PMCID: PMC5600956 DOI: 10.3389/fnmol.2017.00290] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 08/28/2017] [Indexed: 12/12/2022] Open
Abstract
Fragile X syndrome (FXS), is caused by a loss-of-function mutation in the FMR1 gene located on the X-chromosome, which leads to the most common cause of inherited intellectual disability in males and the leading single-gene defect associated with autism. A full mutation (FM) is represented by more than 200 CGG repeats within the FMR1 gene, resulting in FXS. A FM is inherited from women carrying a FM or a premutation (PM; 55–200 CGG repeats) allele. PM is associated with phenotypes distinct from those associated with FM. Some manifestations of the PM are unique; fragile-X-associated tremor/ataxia syndrome (FXTAS), and fragile-X-associated primary ovarian insufficiency (FXPOI), while others tend to be non-specific such as intellectual disability. In addition, women carrying a PM may suffer from subfertility or infertility. There is a need to elucidate whether the impairment of ovarian function found in PM carriers arises during the primordial germ cell (PGC) development stage, or due to a rapidly diminishing oocyte pool throughout life or even both. Due to the possibility of expansion into a FM in the next generation, and other ramifications, carrying a PM can have an enormous impact on one’s life; therefore, preconception counseling for couples carrying the PM is of paramount importance. In this review, we will elaborate on the clinical manifestations in female PM carriers and propose the definition of fragile-X-associated diminished ovarian reserve (FXDOR), then we will review recent scientific findings regarding possible mechanisms leading to FXDOR and FXPOI. Lastly, we will discuss counseling, preventative measures and interventions available for women carrying a PM regarding different aspects of their reproductive life, fertility treatment, pregnancy, prenatal testing, contraception and fertility preservation options.
Collapse
Affiliation(s)
- Limor Man
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Jovana Lekovich
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Zev Rosenwaks
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Jeannine Gerhardt
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| |
Collapse
|
15
|
Wang B, Li L, Zhu Y, Zhang W, Wang X, Chen B, Li T, Pan H, Wang J, Kee K, Cao Y. Sequence variants of KHDRBS1 as high penetrance susceptibility risks for primary ovarian insufficiency by mis-regulating mRNA alternative splicing. Hum Reprod 2017; 32:2138-2146. [DOI: 10.1093/humrep/dex263] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 08/03/2017] [Indexed: 11/12/2022] Open
|
16
|
Khalaj K, Miller JE, Fenn CR, Ahn S, Luna RL, Symons L, Monsanto SP, Koti M, Tayade C. RNA-Binding Proteins in Female Reproductive Pathologies. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:1200-1210. [PMID: 28408123 DOI: 10.1016/j.ajpath.2017.01.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 01/26/2017] [Indexed: 12/14/2022]
Abstract
RNA-binding proteins are key regulatory molecules involved primarily in post-transcriptional gene regulation of RNAs. Post-transcriptional gene regulation is critical for adequate cellular growth and survival. Recent reports have shown key interactions between these RNA-binding proteins and other regulatory elements, such as miRNAs and long noncoding RNAs, either enhancing or diminishing their response to RNA stabilization. Many RNA-binding proteins have been reported to play a functional role in mediation of cytokines involved in inflammation and immune dysfunction, and some have been classified as global post-transcriptional regulators of inflammation. The ubiquitous expression of RNA-binding proteins in a wide variety of cell types and their unique mechanisms of degradative action provide evidence that they are involved in reproductive tract pathologies. Aberrant inflammation and immune dysfunction are major contributors to the pathogenesis and disease pathophysiology of many reproductive pathologies, including ovarian and endometrial cancers in the female reproductive tract. Herein, we discuss various RNA-binding proteins and their unique contributions to female reproductive pathologies with a focus on those mediated by aberrant inflammation and immune dysfunction.
Collapse
Affiliation(s)
- Kasra Khalaj
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Jessica E Miller
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Christian R Fenn
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - SooHyun Ahn
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Rayana L Luna
- Ultrastructure Laboratory, Aggeu Magalhães Research Center of the Oswaldo Cruz Foundation, Recife, Brazil
| | - Lindsey Symons
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Stephany P Monsanto
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Madhuri Koti
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Chandrakant Tayade
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.
| |
Collapse
|
17
|
La Rosa P, Bielli P, Compagnucci C, Cesari E, Volpe E, Farioli Vecchioli S, Sette C. Sam68 promotes self-renewal and glycolytic metabolism in mouse neural progenitor cells by modulating Aldh1a3 pre-mRNA 3'-end processing. eLife 2016; 5. [PMID: 27845622 PMCID: PMC5122457 DOI: 10.7554/elife.20750] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/14/2016] [Indexed: 12/20/2022] Open
Abstract
The balance between self-renewal and differentiation of neural progenitor cells (NPCs) dictates neurogenesis and proper brain development. We found that the RNA- binding protein Sam68 (Khdrbs1) is strongly expressed in neurogenic areas of the neocortex and supports the self-renewing potential of mouse NPCs. Knockout of Khdrbs1 constricted the pool of proliferating NPCs by accelerating their cell cycle exit and differentiation into post-mitotic neurons. Sam68 function was linked to regulation of Aldh1a3 pre-mRNA 3'-end processing. Binding of Sam68 to an intronic polyadenylation site prevents its recognition and premature transcript termination, favoring expression of a functional enzyme. The lower ALDH1A3 expression and activity in Khdrbs1-/- NPCs results in reduced glycolysis and clonogenicity, thus depleting the embryonic NPC pool and limiting cortical expansion. Our study identifies Sam68 as a key regulator of NPC self-renewal and establishes a novel link between modulation of ALDH1A3 expression and maintenance of high glycolytic metabolism in the developing cortex. DOI:http://dx.doi.org/10.7554/eLife.20750.001 Neurons develop from cells called neural progenitors. These cells can either divide to produce more progenitor cells or develop into specific types of neurons. These two activities – known as self-renewal and differentiation – must be balanced to produce the right number of specialized neurons, without depleting the pool of progenitor cells. The self-renewal and differentiation of progenitor cells is balanced by essentially regulating which genes are active, or expressed, within the cells. In the first step of gene expression, the genetic instructions are copied to form a molecule of pre-messenger RNA (or pre-mRNA for short). Each pre-mRNA molecule is then processed to produce a final product that can be translated into protein. Importantly, two copies of the same pre-mRNA may sometimes be processed in different ways, which allows multiple proteins to be produced from a single gene. RNA-binding proteins control pre-mRNA processing. The expression of one such protein, called Sam68, oscillates during the development of the nervous system, such that its expression peaks when there is intense production of new neurons and then declines. However, it was not known whether Sam68 actually helps neurons to develop. La Rosa et al. have now analysed the role of Sam68 in the developing brain of mice. The experiments confirmed that Sam68 is highly expressed in neural progenitor cells and showed that its levels dictate the cell’s fate: high expression encourages a cell to self-renew, while low expression triggers it to develop into a specialized neuron. Further investigation revealed that Sam68 works by promoting the expression of a metabolic enzyme called Aldehyde Dehydrogenase 1A3 or ALDH1A3. This enzyme promotes the release of energy from molecules of glucose via a process known as anaerobic glycolysis. La Rosa et al. found that cells that lack Sam68 make a truncated version of the pre-mRNA encoding ALDH1A3. This truncated pre-mRNA encodes a shortened version of the enzyme that is inactive. Further experiments confirmed that Sam68 normally prevents this from happening by binding to the pre-mRNA and processing it to produce the full-length, working version of the ALDH1A3 enzyme. Also, La Rosa et al. found that progenitor cells need working ALDH1A3 to keep them dividing, and to stop them from developing into specialized neurons too soon. Finally, because the processing of pre-RNA plays a major role in brain development, problems with this process often lead to intellectual disabilities and neurodegenerative diseases, such as autism spectrum disorder and amyotrophic lateral sclerosis. The next step following on from these new findings will be to investigate whether defects in Sam68 contribute to such conditions and, if so, to look for ways to counteract these defects. DOI:http://dx.doi.org/10.7554/eLife.20750.002
Collapse
Affiliation(s)
- Piergiorgio La Rosa
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
| | - Pamela Bielli
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
| | - Claudia Compagnucci
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
| | - Eleonora Cesari
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
| | - Elisabetta Volpe
- Laboratory of Neuroimmunology, Fondazione Santa Lucia, Rome, Italy
| | | | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
| |
Collapse
|
18
|
Dong L, Che H, Li M, Li X. Sam68 is Overexpressed in Epithelial Ovarian Cancer and Promotes Tumor Cell Proliferation. Med Sci Monit 2016; 22:3248-56. [PMID: 27623016 PMCID: PMC5031168 DOI: 10.12659/msm.899980] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Epithelial ovarian cancer (EOC) is the deadliest gynecological malignancy, and evidence is accumulating on how molecular markers may be associated with the origin and process of EOC. Sam68 (Src-associated in mitosis, of 68 kD), is a K homology domain RNA-binding protein that has been investigated as a risk factor in multiple types of tumors. The aim of the present study was to investigate the contribution of the Sam68 gene in the pathogenesis of EOC. MATERIAL AND METHODS Western blot assay and real-time quantitative PCR methods were performed to examine Sam68 expression in EOC tissue specimens. The association of Sam68 expression with clinic-pathologic variables of EOC was evaluated. Then gain-of-function and loss-of-function strategies were adopted to examine the regulation of Sam68 on the proliferation of EOC OVCAR-3 cells using CCK-8 and colony forming assays. RESULTS Sam68 was overexpressed in both mRNA and protein levels in EOC tumor tissue (n=152) in an association with malignant factors of EOC such as International Federation of Gynecology and Obstetrics (FIGO) stage, residual tumor size (cm), histological grade, and lymph node metastasis. In vitro results demonstrated that Sam68 overexpression was upregulated while Sam68 knockdown downregulated the proliferation of EOC OVCAR-3 cells via regulation of cell growth and colony formation. CONCLUSIONS Sam68 was overexpressed in EOC tissue in association with such cancer malignant factors of FIGO stage, histological grade, and lymph node metastasis, and also positively regulated the proliferation of EOC cells. Our research suggests that Sam68 might accelerate cell cycle progression, and present as a prognostic marker for EOC.
Collapse
Affiliation(s)
- Lijuan Dong
- Department of Obstetrics and Gynecology, Zaozhuang Municipal Hospital, Zaozhuang, Shandong, China (mainland)
| | - Hailuo Che
- Department of Obstetrics and Gynecology, Zaozhuang Municipal Hospital, Zaozhuang, Shandong, China (mainland)
| | - Mingmei Li
- , Health and Family Planning Bureau in Shanting District, Zaozhuang, Shandong, China (mainland)
| | - Xuepeng Li
- Department of Obstetrics and Gynecology, Zaozhuang Municipal Hospital, Zaozhuang, Shandong, China (mainland)
| |
Collapse
|
19
|
Pagliarini V, Pelosi L, Bustamante MB, Nobili A, Berardinelli MG, D'Amelio M, Musarò A, Sette C. SAM68 is a physiological regulator of SMN2 splicing in spinal muscular atrophy. J Cell Biol 2015; 211:77-90. [PMID: 26438828 PMCID: PMC4602033 DOI: 10.1083/jcb.201502059] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 08/31/2015] [Indexed: 02/05/2023] Open
Abstract
Knockout of the splicing factor SAM68 promotes SMN2 splicing, improving neuromuscular defects and viability in SMA mice. Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by loss of motor neurons in patients with null mutations in the SMN1 gene. The almost identical SMN2 gene is unable to compensate for this deficiency because of the skipping of exon 7 during pre–messenger RNA (mRNA) processing. Although several splicing factors can modulate SMN2 splicing in vitro, the physiological regulators of this disease-causing event are unknown. We found that knockout of the splicing factor SAM68 partially rescued body weight and viability of SMAΔ7 mice. Ablation of SAM68 function promoted SMN2 splicing and expression in SMAΔ7 mice, correlating with amelioration of SMA-related defects in motor neurons and skeletal muscles. Mechanistically, SAM68 binds to SMN2 pre-mRNA, favoring recruitment of the splicing repressor hnRNP A1 and interfering with that of U2AF65 at the 3′ splice site of exon 7. These findings identify SAM68 as the first physiological regulator of SMN2 splicing in an SMA mouse model.
Collapse
Affiliation(s)
- Vittoria Pagliarini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Laura Pelosi
- Institute Pasteur Cenci-Bolognetti Foundation, DAHFMO-Unit of Histology and Medical Embryology, IIM, University of Rome La Sapienza, 00161 Rome, Italy
| | - Maria Blaire Bustamante
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Annalisa Nobili
- Laboratory of Molecular Neuroscience, Fondazione Santa Lucia, 00143 Rome, Italy Medical School University Campus Bio-Medico, 00128 Rome, Italy
| | - Maria Grazia Berardinelli
- Institute Pasteur Cenci-Bolognetti Foundation, DAHFMO-Unit of Histology and Medical Embryology, IIM, University of Rome La Sapienza, 00161 Rome, Italy
| | - Marcello D'Amelio
- Laboratory of Molecular Neuroscience, Fondazione Santa Lucia, 00143 Rome, Italy Medical School University Campus Bio-Medico, 00128 Rome, Italy
| | - Antonio Musarò
- Institute Pasteur Cenci-Bolognetti Foundation, DAHFMO-Unit of Histology and Medical Embryology, IIM, University of Rome La Sapienza, 00161 Rome, Italy Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, 00161 Rome, Italy
| | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| |
Collapse
|
20
|
SAM68: Signal Transduction and RNA Metabolism in Human Cancer. BIOMED RESEARCH INTERNATIONAL 2015; 2015:528954. [PMID: 26273626 PMCID: PMC4529925 DOI: 10.1155/2015/528954] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 02/24/2015] [Indexed: 12/21/2022]
Abstract
Alterations in expression and/or activity of splicing factors as well as mutations in cis-acting
splicing regulatory sequences contribute to cancer phenotypes. Genome-wide
studies have revealed more than 15,000 tumor-associated splice variants derived from
genes involved in almost every aspect of cancer cell biology, including proliferation,
differentiation, cell cycle control, metabolism, apoptosis, motility, invasion, and
angiogenesis. In the past decades, several RNA binding proteins (RBPs) have been
implicated in tumorigenesis. SAM68 (SRC associated in mitosis of 68 kDa) belongs to
the STAR (signal transduction and activation of RNA metabolism) family of RBPs.
SAM68 is involved in several steps of mRNA metabolism, from transcription to
alternative splicing and then to nuclear export. Moreover, SAM68 participates in signaling
pathways associated with cell response to stimuli, cell cycle transitions, and viral
infections. Recent evidence has linked this RBP to the onset and progression of
different tumors, highlighting misregulation of SAM68-regulated splicing events as a
key step in neoplastic transformation and tumor progression. Here we review recent
studies on the role of SAM68 in splicing regulation and we discuss its contribution to
aberrant pre-mRNA processing in cancer.
Collapse
|
21
|
Knockout of RNA Binding Protein MSI2 Impairs Follicle Development in the Mouse Ovary: Characterization of MSI1 and MSI2 during Folliculogenesis. Biomolecules 2015; 5:1228-44. [PMID: 26131972 PMCID: PMC4598749 DOI: 10.3390/biom5031228] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/29/2015] [Accepted: 06/09/2015] [Indexed: 01/20/2023] Open
Abstract
Characterizing the mechanisms underlying follicle development in the ovary is crucial to understanding female fertility and is an area of increasing research interest. The RNA binding protein Musashi is essential for post-transcriptional regulation of oocyte maturation in Xenopus and is expressed during ovarian development in Drosophila. In mammals Musashi is important for spermatogenesis and male fertility, but its role in the ovary has yet to be characterized. In this study we determined the expression of mammalian Musashi proteins MSI1 and MSI2 during mouse folliculogenesis, and through the use of a MSI2-specific knockout mouse model we identified that MSI2 is essential for normal follicle development. Time-course characterization of MSI1 and MSI2 revealed distinct differences in steady-state mRNA levels and protein expression/localization at important developmental time-points during folliculogenesis. Using a gene-trap mouse model that inactivates Msi2, we observed a significant decrease in ovarian mass, and change in follicle-stage composition due to developmental blocking of antral stage follicles and pre-antral follicle loss through atresia. We also confirmed that hormonally stimulated Msi2-deficient mice produce significantly fewer MII oocytes (60.9% less than controls, p < 0.05). Furthermore, the majority of these oocytes are of poor viability (62.2% non-viable/apoptotic, p < 0.05), which causes a reduction in female fertility evidenced by decreased litter size in Msi2-deficient animals (33.1% reduction to controls, p < 0.05). Our findings indicate that MSI1 and MSI2 display distinct expression profiles during mammalian folliculogenesis and that MSI2 is required for pre-antral follicle development.
Collapse
|
22
|
Wang Q, Li Y, Zhou J, Liu J, Qin J, Xing F, Zhang J, Cheng J. Clinical significance of Sam68 expression in endometrial carcinoma. Tumour Biol 2015; 36:4509-18. [PMID: 25874492 DOI: 10.1007/s13277-015-3095-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 01/08/2015] [Indexed: 12/19/2022] Open
Abstract
Sam68 (Src-associated in mitosis of 68 kDa) is a substrate for tyrosine kinase c-Src during mitosis. The nuclear protein level has been found to be associated with progression and prognosis in various human malignant tumors. The aim of this study is to investigate the clinical value of Sam68 in endometrial carcinoma (EC). Sam68 expression was confirmed by real-time PCR, Western blot, and immunofluorescent assay in primary normal endometrial epithelial cells, endometrial carcinoma cell lines, as well as seven pairs of EC and matched adjacent noncancerous endometrial tissues. Moreover, the protein level of Sam68 was evaluated by immunohistochemistry in a cohort of surgical specimens derived from 131 patients including primary endometrial carcinoma (n = 95), endometrial atypical hyperplasia (precancerous lesions, n = 26), and normal endometria (n = 10). In endometrial cancer cell lines, RNA interfering approach was employed to downregulate Sam68 expression to determine its role in proliferation. Clinicopathological relevance and prognostic associations were examined by statistical analyses. Compared with normal endometrial and endometrial atypical hyperplasia tissues, Sam68 significantly elevated in endometrial cancer samples (P < 0.01), which was negative or low in 37 cases (38.9 %) and high in 58 cases (61.1 %). The high expression of Sam68 was associated with histological grade (P < 0.001), FIGO stage (P = 0.039), and myometrial invasion (P = 0.002). Kaplan-Meier analysis demonstrated that overexpression of Sam68 correlated with shorter overall survival. It is confirmed by univariate and multivariate analysis (P < 0.001 and P = 0.048, respectively). Additionally, we found that Sam68 was highly expressed at both the transcriptional and translational levels in endometrial cancer cell lines (Ishikawa, HEC-1B, AN3CA, KLE, and RL95-2) and siRNA knockdown of Sam68 remarkably inhibited cellular proliferation in in vitro models. Sam68 may be useful prognostic marker for EC, and it plays an important role in promoting the cellular proliferation. Further investigation of Sam68 as a potential therapeutic target for EC patients could be of interest.
Collapse
Affiliation(s)
- Qingying Wang
- Department of Obstetrics and Gynecology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Yanchang Middle Road, Shanghai, 200072, China
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Elizur SE, Lebovitz O, Derech-Haim S, Dratviman-Storobinsky O, Feldman B, Dor J, Orvieto R, Cohen Y. Elevated levels of FMR1 mRNA in granulosa cells are associated with low ovarian reserve in FMR1 premutation carriers. PLoS One 2014; 9:e105121. [PMID: 25153074 PMCID: PMC4143194 DOI: 10.1371/journal.pone.0105121] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 07/17/2014] [Indexed: 11/25/2022] Open
Abstract
Aim To assess the role of mRNA accumulation in granulosa cells as the cause of low ovarian response among FMR1 premutation carriers undergoing pre-implantation genetic diagnosis (PGD). Design Case control study in an academic IVF unit. Twenty-one consecutive FMR1 premutation carriers and 15 control women were included. After oocyte retrieval the granulosa cells mRNA levels of FMR1 was measured using RT-PCR. Results In FMR1 premutation carriers, there was a significant non-linear association between the number of CGG repeats and the number of retrieved oocytes (p<0.0001) and a trend to granulosa cells FMR1 mRNA levels (p = 0.07). The lowest number of retrieved oocytes and the highest level of mRNA were seen in women with mid-size CGG repeats (80–120). A significant negative linear correlation was observed between the granulosa cells FMR1 mRNA levels and the number of retrieved oocytes (R2 linear = 0.231, P = 0.02). Conclusion We suggest that there is a no-linear association between the number of CGG repeats and ovarian function, resulting from an increased granulosa cells FMR1 mRNA accumulation in FMR1 carriers in the mid-range (80–120 repeats).
Collapse
Affiliation(s)
- Shai E. Elizur
- Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, (Tel Hashomer), Ramat Gan, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Oshrit Lebovitz
- Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, (Tel Hashomer), Ramat Gan, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sanaz Derech-Haim
- Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, (Tel Hashomer), Ramat Gan, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Olga Dratviman-Storobinsky
- Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, (Tel Hashomer), Ramat Gan, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Baruch Feldman
- Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, (Tel Hashomer), Ramat Gan, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Jehoshua Dor
- Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, (Tel Hashomer), Ramat Gan, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Raoul Orvieto
- Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, (Tel Hashomer), Ramat Gan, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yoram Cohen
- Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, (Tel Hashomer), Ramat Gan, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- * E-mail:
| |
Collapse
|
24
|
Li LJ, Zhang FB, Liu SY, Tian YH, Le F, Lou HY, Huang HF, Jin F. Decreased expression of SAM68 in human testes with spermatogenic defects. Fertil Steril 2014; 102:61-67.e3. [PMID: 24794312 DOI: 10.1016/j.fertnstert.2014.03.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 03/02/2014] [Accepted: 03/20/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To assess the expression patterns of SAM68 in the testes of azoospermic patients with normal and abnormal spermatogenesis. DESIGN Retrospective study and in vitro study. SETTING University hospital. PATIENT(S) Testicular biopsies of azoospermic men with normal spermatogenesis (OAZ; n=20), with maturation arrest at the spermatocyte stage (MA; n=20), and with Sertoli cell-only syndrome (SCOS; n=10). INTERVENTION(S) No interventions with patients. Knockdown of Sam68 was performed in the GC-2spd(ts) cell line. MAIN OUTCOME MEASURE(S) SAM68 expression was analyzed using quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, and immunohistochemistry analysis in tissues. Moreover, Sam68 was knocked down in GC-2spd(ts) cells. Cell viability was measured using the MTT assay, and the apoptosis rate was detected using flow cytometry with the Annexin V-FITC kit. RESULT(S) Using qRT-PCR, the expression level of testicular SAM68 mRNA in MA and SCOS patients was statistically reduced compared with in OAZ patients. In addition, using qRT-PCR, Western blot, and immunohistochemistry analyses, mRNA and protein expressions of SAM68 were absent or barely detectable in testicular tissues in 45% (9 of 20) of patients with MA and in all patients with SCOS. Furthermore, decreased expression of Sam68 suppressed germ cell proliferation and induced apoptosis in transfected GC-2spd(ts) cells. CONCLUSION(S) Deficient SAM68 expression was observed in the human testis with MA at the spermatocyte stage and SCOS. These results may offer new perspectives on the molecular basis of abnormal spermatogenesis.
Collapse
Affiliation(s)
- Le-Jun Li
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Feng-Bin Zhang
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Shu-Yuan Liu
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Yong-Hong Tian
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Fang Le
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Hang-Ying Lou
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - He-Feng Huang
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Fan Jin
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China; Key Laboratory of Reproductive Genetics, National Ministry of Education (Zhejiang University), Women's Reproductive Health Laboratory of Zhejiang Province, Hangzhou, Zhejiang, People's Republic of China.
| |
Collapse
|
25
|
Sánchez-Jiménez F, Sánchez-Margalet V. Role of Sam68 in post-transcriptional gene regulation. Int J Mol Sci 2013; 14:23402-19. [PMID: 24287914 PMCID: PMC3876053 DOI: 10.3390/ijms141223402] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/11/2013] [Accepted: 11/13/2013] [Indexed: 01/10/2023] Open
Abstract
The STAR family of proteins links signaling pathways to various aspects of post-transcriptional regulation and processing of RNAs. Sam68 belongs to this class of heteronuclear ribonucleoprotein particle K (hnRNP K) homology (KH) single domain-containing family of RNA-binding proteins that also contains some domains predicted to bind critical components in signal transduction pathways. In response to phosphorylation and other post-transcriptional modifications, Sam68 has been shown to have the ability to link signal transduction pathways to downstream effects regulating RNA metabolism, including transcription, alternative splicing or RNA transport. In addition to its function as a docking protein in some signaling pathways, this prototypic STAR protein has been identified to have a nuclear localization and to take part in the formation of both nuclear and cytosolic multi-molecular complexes such as Sam68 nuclear bodies and stress granules. Coupling with other proteins and RNA targets, Sam68 may play a role in the regulation of differential expression and mRNA processing and translation according to internal and external signals, thus mediating important physiological functions, such as cell death, proliferation or cell differentiation.
Collapse
Affiliation(s)
- Flora Sánchez-Jiménez
- Department of Medical Biochemistry and Molecular Biology and Immunology, UGC Clinical Biochemistry, Virgen Macarena University Hospital, Avenue. Sánchez Pizjuan 4, Medical School, University of Seville, Seville 41009, Spain.
| | | |
Collapse
|
26
|
Abstract
Alternative splicing is well known to be tissue-specific. Although several genes have been shown to undergo alternative splicing in adipocytes, little is known about the mechanism that regulates alternative splicing during adipogenesis. We recently reported that Sam68−/− mice exhibit a lean phenotype and are protected against diet-induced obesity. Our genome-wide exon array analysis in white adipose tissue (WAT) from wild-type and Sam68−/− mice revealed that Sam68 deficiency leads to an abnormal splicing of the mTOR gene. This has been shown to reduce the overall mTOR protein content and activity during in vitro adipose differentiation. In Sam68−/− mice, this situation leads to an increased energy expenditure, decreased adipogenesis and WAT formation.
Collapse
|
27
|
Vogel G, Richard S. Emerging roles for Sam68 in adipogenesis and neuronal development. RNA Biol 2012; 9:1129-33. [PMID: 23018781 DOI: 10.4161/rna.21409] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Sam68, the Src-associated substrate during mitosis of 68 kDa, belongs to the large class of heteronuclear ribonucleoprotein particle K (hnRNP K) homology (KH) domain family of RNA-binding proteins. Sam68 contains a single KH domain harboring conserved N- and C-terminal sequences required for RNA binding and homodimerization. The KH domain is one of the most prevalent RNA binding domains that directly contacts single-stranded RNA. Sam68 has been implicated in numerous aspects of RNA metabolism including alternative splicing and polysomal recruitment of mRNAs. Studies in mice have revealed physiological roles linking Sam68 to osteoporosis, obesity, cancer, infertility and ataxia. Recent publications have greatly enhanced our understanding of Sam68 mechanism of action in addition to its cellular role. Herein, we will discuss the latest advances in the literature pertaining to obesity and neuronal development.
Collapse
Affiliation(s)
- Gillian Vogel
- Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research and Departments of Oncology and Medicine, McGill University, Montréal, QC Canada
| | | |
Collapse
|
28
|
Hoffman GE, Le WW, Entezam A, Otsuka N, Tong ZB, Nelson L, Flaws JA, McDonald JH, Jafar S, Usdin K. Ovarian abnormalities in a mouse model of fragile X primary ovarian insufficiency. J Histochem Cytochem 2012; 60:439-56. [PMID: 22470123 PMCID: PMC3393073 DOI: 10.1369/0022155412441002] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 02/04/2012] [Indexed: 11/22/2022] Open
Abstract
FMR1 premutation (PM) alleles have 55-200 CGG·CCG-repeats in their 5' UTR. PM carriers are at risk of fragile X-associated tremor and ataxia syndrome (FXTAS). Females are also at risk for FX primary ovarian insufficiency (FXPOI). PM pathology is generally attributed to deleterious properties of transcripts with long CGG-tracts. For FXPOI, hormone changes suggest a reduced residual follicle pool. Whether this is due to a smaller than normal original follicle pool or an increased rate of follicle depletion is unclear. A FX-PM mouse the authors generated with 130 CGG·CCG-repeats in the endogenous Fmr1 gene recapitulates features of FXTAS. Here the authors demonstrate that the gross development of the ovary and the establishment of the primordial follicle pool is normal in these mice. However, these animals show a faster loss of follicles of all follicle classes, suggesting that the problem is intrinsic to the ovary. In addition, many oocytes show aberrant nuclear accumulation of FMRP and elevated levels of ubiquitination. Furthermore, PM follicles are smaller and have fewer granulosa cells (GCs) than normal. Thus, these animals have ovarian abnormalities involving both the oocytes and GCs that may shed light on the molecular basis of FXPOI in humans.
Collapse
Affiliation(s)
- Gloria E Hoffman
- Department of Biology, Morgan State University, Baltimore, MD 21251, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Huot MÉ, Vogel G, Zabarauskas A, Ngo CTA, Coulombe-Huntington J, Majewski J, Richard S. The Sam68 STAR RNA-binding protein regulates mTOR alternative splicing during adipogenesis. Mol Cell 2012; 46:187-99. [PMID: 22424772 DOI: 10.1016/j.molcel.2012.02.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 12/28/2011] [Accepted: 02/10/2012] [Indexed: 11/16/2022]
Abstract
We report that mice ablated for the Sam68 RNA-binding protein exhibit a lean phenotype as a result of increased energy expenditure, decreased commitment to early adipocyte progenitors, and defects in adipogenic differentiation. The Sam68(-/-) mice were protected from obesity, insulin resistance, and glucose intolerance induced with a high-fat diet. To identify the alternative splice events regulated by Sam68, genome-wide exon usage profiling in white adipose tissue was performed. Adipocytes from Sam68(-/-) mice retained intron 5 within the mTOR transcript introducing a premature termination codon, leading to an unstable mRNA. Consequently, Sam68-depleted cells had reduced mTOR levels resulting in lower levels of insulin-stimulated S6 and Akt phosphorylation leading to defects in adipogenesis, and this defect was rescued by the exogenous expression of full-length mTOR. Sam68 bound intronic splice elements within mTOR intron 5 required for the usage of the 5' splice site. We propose that Sam68 regulates alternative splicing during adipogenesis.
Collapse
Affiliation(s)
- Marc-Étienne Huot
- Terry Fox Molecular Oncology Group and Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research, McGill University, Montreal, QC H3T 1E2, Canada
| | | | | | | | | | | | | |
Collapse
|
30
|
Bielli P, Busà R, Paronetto MP, Sette C. The RNA-binding protein Sam68 is a multifunctional player in human cancer. Endocr Relat Cancer 2011; 18:R91-R102. [PMID: 21565971 DOI: 10.1530/erc-11-0041] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Src associated in mitosis, of 68 kDa (Sam68) is a KH domain RNA-binding protein that belongs to the signal transduction and activation of RNA family. Although ubiquitously expressed, Sam68 plays very specialized roles in different cellular environments. In most cells, Sam68 resides in the nucleus and is involved in several steps of mRNA processing, from transcription, to alternative splicing, to nuclear export. In addition, Sam68 translocates to the cytoplasm upon cell stimulation, cell cycle transitions or viral infections, where it takes part to signaling complexes and associates with the mRNA translation machinery. Recent evidence has linked Sam68 function to the onset and progression of endocrine tumors, such as prostate and breast carcinomas. Notably, all the biochemical activities reported for Sam68 seem to be implicated in carcinogenesis. Herein, we review the recent advancement in the knowledge of Sam68 function and regulation and discuss it in the frame of its participation to neoplastic transformation and tumor progression.
Collapse
Affiliation(s)
- Pamela Bielli
- Department of Public Health and Cell Biology, University of Rome Tor Vergata, Italy
| | | | | | | |
Collapse
|
31
|
Gunter KM, McLaughlin EA. Translational control in germ cell development: A role for the RNA-binding proteins Musashi-1 and Musashi-2. IUBMB Life 2011; 63:678-85. [PMID: 21766416 DOI: 10.1002/iub.499] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 04/13/2011] [Indexed: 12/26/2022]
Abstract
Mammalian gametogenesis is a complex process involving specialised cell cycle progression and differentiation. As part of their differentiation, germ cells experience periods of transcriptional inactivation and chromatin inaccessibility whilst continuing to coordinate the correct temporal and spatial expression of genes required for continued development. To overcome these obstacles, mammalian germ cells express a wide variety of sequence-specific RNA-binding proteins, which assist in the translational control of many mRNA transcripts which are produced and stored during periods of high mRNA synthesis. In this review we focus on the Musashi family of RNA-binding proteins, a highly conserved family of translational regulatory proteins whose recent identification in germ cells of Drosophila and Xenopus, as well as their well described role in processes such as cell cycle progression and stem cell identity, has led us to investigate the role of these proteins in mammalian germ cell development.
Collapse
Affiliation(s)
- Kara M Gunter
- Reproductive Science Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | | |
Collapse
|
32
|
Sánchez-Jiménez F, Pérez-Pérez A, González-Yanes C, Varone CL, Sánchez-Margalet V. Sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic JEG-3 cells. Hum Reprod 2011; 26:2306-15. [PMID: 21672929 DOI: 10.1093/humrep/der187] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Sam68, a member of the signal transduction and activation of RNA metabolism (STAR) family of RNA-binding proteins, has been previously implicated as an adaptor molecule in different signaling systems, including leptin receptor (LEPR) signaling. LEPR activation is known to stimulate JAK-STAT, MAPK and PI3K signaling pathways, thus mediating the biological effects of leptin in different cell types, including trophoblastic cells. We have recently found that leptin stimulation also promotes the overexpression and tyrosine phosphorylation of Sam68 in human trophoblastic JEG-3 cells, suggesting a role for Sam68 in leptin signaling and action in these cells. In the present work, we have studied the participation of Sam68 in the main signaling pathways activated by LEPR to increase growth and proliferation in trophoblastic JEG-3 cells. METHODS We used an antisense strategy to down-regulate Sam68 expression in these cells, and we studied LEPR signaling by immunoprecipitation and poly-U affinity precipitation and by analyzing phosphorylation levels of signaling proteins by immunoblot. The effect of leptin on protein synthesis and proliferation was studied by ³[H]-leucine and ³[H]-thymidine incorporation. RESULTS Sam68 knockdown impaired leptin activation of JAK-STAT, PI3K and MAPK signaling pathways in JEG-3 cells. We have also found that leptin-stimulated Sam68 tyrosine phosphorylation is dependent on JAK-2 activity, since the pharmacological inhibitor AG490 prevents the phosphorylation of Sam68 in JEG-3 cells. Finally, the trophic and proliferative effect of leptin in trophoblastic cells is dependent on Sam68 expression, since its down-regulation impaired the leptin-stimulated DNA and protein synthesis. CONCLUSIONS These data demonstrate that Sam68 participates in the main signaling pathways of LEPR to mediate the trophic and proliferative effect of leptin in human trophoblastic cells.
Collapse
Affiliation(s)
- F Sánchez-Jiménez
- Department of Clinical Biochemistry, Virgen Macarena University Hospital, University of Seville, Seville 41071, Spain
| | | | | | | | | |
Collapse
|
33
|
Post-transcriptional control of gene expression in mouse early embryo development: a view from the tip of the iceberg. Genes (Basel) 2011; 2:345-59. [PMID: 24710195 PMCID: PMC3924817 DOI: 10.3390/genes2020345] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 02/22/2011] [Accepted: 04/02/2011] [Indexed: 11/17/2022] Open
Abstract
Fertilization is a very complex biological process that requires the perfect cooperation between two highly specialized cells: the male and female gametes. The oocyte provides the physical space where this process takes place, most of the energetic need, and half of the genetic contribution. The spermatozoon mostly contributes the other half of the chromosomes and it is specialized to reach and to penetrate the oocyte. Notably, the mouse oocyte and early embryo are transcriptionally inactive. Hence, they fully depend on the maternal mRNAs and proteins stored during oocyte maturation to drive the onset of development. The new embryo develops autonomously around the four-cell stage, when maternal supplies are exhausted and the zygotic genome is activated in mice. This oocyte-to-embryo transition needs an efficient and tightly regulated translation of the maternally-inherited mRNAs, which likely contributes to embryonic genome activation. Full understanding of post-transcriptional regulation of gene expression in early embryos is crucial to understand the reprogramming of the embryonic genome, it might help driving reprogramming of stem cells in vitro and will likely improve in vitro culturing of mammalian embryos for assisted reproduction. Nevertheless, the knowledge of the mechanism(s) underlying this fundamental step in embryogenesis is still scarce, especially if compared to other model organisms. We will review here the current knowledge on the post-transcriptional control of gene expression in mouse early embryos and discuss some of the unanswered questions concerning this fascinating field of biology.
Collapse
|
34
|
Paronetto MP, Messina V, Barchi M, Geremia R, Richard S, Sette C. Sam68 marks the transcriptionally active stages of spermatogenesis and modulates alternative splicing in male germ cells. Nucleic Acids Res 2011; 39:4961-74. [PMID: 21355037 PMCID: PMC3130265 DOI: 10.1093/nar/gkr085] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Sam68 plays an essential role in mouse spermatogenesis and male fertility. Herein, we report an interaction between Sam68 and the phosphorylated forms of the RNA polymerase II (RNAPII) in meiotic spermatocytes. RNase treatment decreased but did not abolish the interaction, consistently with in vitro binding of RNAPII to the Sam68 carboxyl-terminal region. Sam68 retention in the spermatocyte nucleus was dependent on the integrity of cellular RNAs, suggesting that the protein is recruited to transcriptionally active chromatin. Mouse knockout models characterized by stage-specific arrest of spermatogenesis and staining with the phosphorylated form of RNAPII documented that Sam68 expression is confined to the transcriptionally active stages of spermatogenesis. Furthermore, Sam68 associates with splicing regulators in germ cells and we report that alternative splicing of Sgce exon 8 is regulated in a Sam68-dependent manner during spermatogenesis. RNA and chromatin crosslink immunoprecipitation experiments showed that Sam68 binds in vivo to sequences surrounding the intron 7/exon 8 boundary, thereby affecting the recruitment of the phosphorylated RNAPII and of the general splicing factor U2AF65. These results suggest that Sam68 regulates alternative splicing at transcriptionally active sites in differentiating germ cells and provide new insights into the regulation of Sam68 expression during spermatogenesis.
Collapse
Affiliation(s)
- Maria Paola Paronetto
- Department of Public Health and Cell Biology, Section of Anatomy, University of Rome, 00133 Rome, Italy
| | | | | | | | | | | |
Collapse
|