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Liao HY, Da CM, Wu ZL, Zhang HH. Ski: Double roles in cancers. Clin Biochem 2020; 87:1-12. [PMID: 33188772 DOI: 10.1016/j.clinbiochem.2020.10.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/29/2020] [Accepted: 10/31/2020] [Indexed: 02/07/2023]
Abstract
The Ski (Sloan-Kettering Institute) is an evolutionarily conserved protein that plays a dual role as an oncoprotein and tumor suppressor gene in the development of human cancer. The Ski oncogene was first identified as a transforming protein of the avian Sloan-Kettering retrovirus in 1986. Since its discovery, Ski has been identified as a carcinogenic regulator in a variety of malignant tumors. Later, it was reported that Ski regulates the occurrence and development of some cancers by acting as an oncogene. Ski mediates the proliferation, differentiation, metastasis, and invasion of numerous cancer cells through various mechanisms. Several studies have shown that Ski expression is correlated with the clinical characteristics of cancer patients and is a promising biomarker and therapeutic target for cancer. In this review, we summarize the mechanisms and potential clinical implications of Ski in dimorphism, cancer occurrence, and progression in various types of cancer.
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Affiliation(s)
- Hai-Yang Liao
- The Second Clinical Medical College of Lanzhou University, 82 Cuiying Men, Lanzhou 730030, PR China; Orthopaedics Key Laboratory of Gansu Province, Lanzhou 730000, PR China
| | - Chao-Ming Da
- The Second Clinical Medical College of Lanzhou University, 82 Cuiying Men, Lanzhou 730030, PR China; Orthopaedics Key Laboratory of Gansu Province, Lanzhou 730000, PR China
| | - Zuo-Long Wu
- The Second Clinical Medical College of Lanzhou University, 82 Cuiying Men, Lanzhou 730030, PR China; Orthopaedics Key Laboratory of Gansu Province, Lanzhou 730000, PR China
| | - Hai-Hong Zhang
- The Second Clinical Medical College of Lanzhou University, 82 Cuiying Men, Lanzhou 730030, PR China; Orthopaedics Key Laboratory of Gansu Province, Lanzhou 730000, PR China.
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2
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Maire P, Dos Santos M, Madani R, Sakakibara I, Viaut C, Wurmser M. Myogenesis control by SIX transcriptional complexes. Semin Cell Dev Biol 2020; 104:51-64. [PMID: 32247726 DOI: 10.1016/j.semcdb.2020.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 02/07/2023]
Abstract
SIX homeoproteins were first described in Drosophila, where they participate in the Pax-Six-Eya-Dach (PSED) network with eyeless, eyes absent and dachsund to drive synergistically eye development through genetic and biochemical interactions. The role of the PSED network and SIX proteins in muscle formation in vertebrates was subsequently identified. Evolutionary conserved interactions with EYA and DACH proteins underlie the activity of SIX transcriptional complexes (STC) both during embryogenesis and in adult myofibers. Six genes are expressed throughout muscle development, in embryonic and adult proliferating myogenic stem cells and in fetal and adult post-mitotic myofibers, where SIX proteins regulate the expression of various categories of genes. In vivo, SIX proteins control many steps of muscle development, acting through feedforward mechanisms: in the embryo for myogenic fate acquisition through the direct control of Myogenic Regulatory Factors; in adult myofibers for their contraction/relaxation and fatigability properties through the control of genes involved in metabolism, sarcomeric organization and calcium homeostasis. Furthermore, during development and in the adult, SIX homeoproteins participate in the genesis and the maintenance of myofibers diversity.
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Affiliation(s)
- Pascal Maire
- Université de Paris, Institut Cochin, INSERM, CNRS, 75014, Paris, France.
| | | | - Rouba Madani
- Université de Paris, Institut Cochin, INSERM, CNRS, 75014, Paris, France
| | - Iori Sakakibara
- Research Center for Advanced Science and Technology, The University of Tokyo, Japan
| | - Camille Viaut
- Université de Paris, Institut Cochin, INSERM, CNRS, 75014, Paris, France
| | - Maud Wurmser
- Department of Integrative Medical Biology (IMB), Umeå universitet, Sweden
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Tecalco-Cruz AC, Ríos-López DG, Vázquez-Victorio G, Rosales-Alvarez RE, Macías-Silva M. Transcriptional cofactors Ski and SnoN are major regulators of the TGF-β/Smad signaling pathway in health and disease. Signal Transduct Target Ther 2018; 3:15. [PMID: 29892481 PMCID: PMC5992185 DOI: 10.1038/s41392-018-0015-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 02/16/2018] [Accepted: 03/15/2018] [Indexed: 12/19/2022] Open
Abstract
The transforming growth factor-β (TGF-β) family plays major pleiotropic roles by regulating many physiological processes in development and tissue homeostasis. The TGF-β signaling pathway outcome relies on the control of the spatial and temporal expression of >500 genes, which depend on the functions of the Smad protein along with those of diverse modulators of this signaling pathway, such as transcriptional factors and cofactors. Ski (Sloan-Kettering Institute) and SnoN (Ski novel) are Smad-interacting proteins that negatively regulate the TGF-β signaling pathway by disrupting the formation of R-Smad/Smad4 complexes, as well as by inhibiting Smad association with the p300/CBP coactivators. The Ski and SnoN transcriptional cofactors recruit diverse corepressors and histone deacetylases to repress gene transcription. The TGF-β/Smad pathway and coregulators Ski and SnoN clearly regulate each other through several positive and negative feedback mechanisms. Thus, these cross-regulatory processes finely modify the TGF-β signaling outcome as they control the magnitude and duration of the TGF-β signals. As a result, any alteration in these regulatory mechanisms may lead to disease development. Therefore, the design of targeted therapies to exert tight control of the levels of negative modulators of the TGF-β pathway, such as Ski and SnoN, is critical to restore cell homeostasis under the specific pathological conditions in which these cofactors are deregulated, such as fibrosis and cancer. Proteins that repress molecular signaling through the transforming growth factor-beta (TGF-β) pathway offer promising targets for treating cancer and fibrosis. Marina Macías-Silva and colleagues from the National Autonomous University of Mexico in Mexico City review the ways in which a pair of proteins, called Ski and SnoN, interact with downstream mediators of TGF-β to inhibit the effects of this master growth factor. Aberrant levels of Ski and SnoN have been linked to diverse range of diseases involving cell proliferation run amok, and therapies that regulate the expression of these proteins could help normalize TGF-β signaling to healthier physiological levels. For decades, drug companies have tried to target the TGF-β pathway, with limited success. Altering the activity of these repressors instead could provide a roundabout way of remedying pathogenic TGF-β activity in fibrosis and oncology.
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Affiliation(s)
- Angeles C Tecalco-Cruz
- 1Instituto de Investigaciones Biomédicas at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
| | - Diana G Ríos-López
- 2Instituto de Fisiología Celular at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
| | | | - Reyna E Rosales-Alvarez
- 2Instituto de Fisiología Celular at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
| | - Marina Macías-Silva
- 2Instituto de Fisiología Celular at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
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Diaz M, Martel N, Fitzsimmons RL, Eriksson NA, Cowin GJ, Thomas GP, Cao KAL, Muscat GEO, Leong GM. Ski overexpression in skeletal muscle modulates genetic programs that control susceptibility to diet-induced obesity and insulin signaling. Obesity (Silver Spring) 2012; 20:2157-67. [PMID: 22513493 DOI: 10.1038/oby.2012.101] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transgenic mice overexpressing chicken Ski (c-Ski) have marked decrease in adipose mass with skeletal muscle hypertrophy. Recent evidence indicates a role for c-Ski in lipogenesis and energy expenditure. In the present study, wild type (WT) and c-Ski mice were challenged on a high-fat (HF) diet to determine whether c-Ski mice were resistant to diet-induced obesity. During the HF feeding WT mice gained significantly more weight than chow-fed animals, while c-Ski mice were partially resistant to the effects of the HF diet on weight. Body composition analysis confirmed the decreased adipose mass in c-Ski mice compared to WT mice. c-Ski mice possess a similar metabolic rate and level of food consumption to WT littermates, despite lower activity levels and on chow diet show mild glucose intolerance relative to WT littermates. On HF diet, glucose tolerance surprisingly remained unchanged in c-Ski mice, while it became worse in WT mice. Skeletal muscle of c-Ski mice exhibit impaired insulin-stimulated Akt phosphorylation and glucose uptake. In concordance, gene expression profiling of skeletal muscle of chow and HF-fed mice indicated that Ski suppresses gene expression associated with insulin signaling and glucose uptake and alters gene pathways involved in myogenesis and adipogenesis. In conclusion, c-Ski mice are partially resistant to diet-induced obesity and display aberrant insulin signaling and glucose homeostasis which is associated with alterations in gene expression that inhibit lipogenesis and insulin signaling. These results suggest Ski plays a major role in skeletal muscle metabolism and adipogenesis and hence influences risk of obesity and diabetes.
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Affiliation(s)
- Marianne Diaz
- The University of Queensland, Obesity Research Centre, Institute for Molecular Bioscience, Queensland, Australia
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5
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Bonnon C, Atanasoski S. c-Ski in health and disease. Cell Tissue Res 2011; 347:51-64. [DOI: 10.1007/s00441-011-1180-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 04/15/2011] [Indexed: 01/28/2023]
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Cunnington RH, Wang B, Ghavami S, Bathe KL, Rattan SG, Dixon IMC. Antifibrotic properties of c-Ski and its regulation of cardiac myofibroblast phenotype and contractility. Am J Physiol Cell Physiol 2010; 300:C176-86. [PMID: 20943957 DOI: 10.1152/ajpcell.00050.2010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cardiac myofibroblasts are key players in chronic remodeling of the cardiac extracellular matrix, which is mediated in part by elevated transforming growth factor-β₁ (TGF-β₁). The c-Ski proto-oncoprotein has been shown to modify TGF-β₁ post-receptor signaling through receptor-activated Smads (R-Smads); however, little is known about how c-Ski regulates fibroblast phenotype and function. We sought to elucidate the function of c-Ski in primary cardiac myofibroblasts using a c-Ski overexpression system. Cardiac myofibroblasts expressed three forms of c-Ski with the predominant band at 105 kDa, and adenoviral c-Ski treatment resulted in overexpression of 95-kDa c-Ski in cellular nuclei. Exogenous c-Ski led to significant inhibition of type I collagen secretion and myofibroblast contractility using two-dimensional semifloating gel contraction assay in both basal and with TGF-β₁ (10 ng/ml for 24 h) stimulation. Overexpressed c-Ski did not inhibit nuclear translocation of phosphorylated R-Smad2, despite their binding, as demonstrated by immunoprecipitation. Acute treatment of primary myofibroblasts with TGF-β₁ in vitro revealed a marked nuclear shuttling of c-Ski at 24 and 48 h following stimulation. Remarkably, overexpression of c-Ski led to a stepwise reduction of the myofibroblast marker α-smooth muscle actin with increasing multiplicity of infection, and these results indicate that 95-kDa c-Ski overexpression may effect a loss of the myofibroblastic phenotype. Furthermore, adenovirus (Ad) for hemagglutinin-tagged c-Ski infection led to a reduction in the number of myofibroblasts versus Ad-LacZ-infected and uninfected controls, due to induction of apoptosis. Finally, we observed a significant increase in 105-kDa c-Ski in the cytosolic fraction of cells of the infarct scar and adjacent remnant myocardium vs. noninfarcted controls.
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Affiliation(s)
- Ryan H Cunnington
- Department of Physiology, Institute of Cardiovascular Sciences, University of Manitoba, Winnipeg, Canada
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7
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Involvement of c-Ski Oncoprotein in Carcinogenesis of Cholangiocacinoma Induced by Opisthorchis viverrini and N-nitrosodimethylamine. Pathol Oncol Res 2010; 17:219-27. [DOI: 10.1007/s12253-010-9300-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 08/12/2010] [Indexed: 12/19/2022]
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Abstract
OBJECTIVE The Ski gene regulates skeletal muscle differentiation in vitro and and in vivo. In the c-Ski overexpression mouse model there occurs marked skeletal muscle hypertrophy with decreased adipose tissue mass. In this study, we have investigated the underlying molecular mechanisms responsible for the increased skeletal muscle and decreased adipose tissue mass in the c-Ski mouse. APPROACH Growth and body composition analysis (tissue weights and dual energy X-ray absorptiometry) coupled with skeletal muscle and white adipose gene expression and metabolic phenotyping in c-Ski mice and wild-type (WT) littermate controls was performed. RESULTS The growth and body composition studies confirmed the early onset of accelerated body growth, with increased lean mass and decreased fat mass in the c-Ski mice. Gene expression analysis in skeletal muscle from c-Ski mice compared with WT mice showed significant differences in myogenic and lipogenic gene expressions that are consistent with the body composition phenotype. Skeletal muscle of c-Ski mice had significantly repressed Smad1, 4, 7 and myostatin gene expression and elevated myogenin, myocyte enhancer factor 2, insulin-like growth factor-1 receptor and insulin-like growth factor-2 expression. Strikingly, expression of the mRNAs encoding the master lipogenic regulators, sterol-regulatory enhancer binding protein 1c (SREBP1c), and the nuclear receptor liver X-receptor-alpha, and their downstream target genes, SCD-1 and FAS, were suppressed in skeletal muscle of c-Ski mice, as were the expressions of other nuclear receptors involved in adipogenesis and metabolism, such as peroxisome proliferator-activated receptor-gamma, glucocorticoid receptor and retinoic acid receptor-related orphan receptor-alpha. Transfection analysis demonstrated Ski repressed the SREBP1c promoter. Moreover, palmitate oxidation and oxidative enzyme activity was increased in skeletal muscle of c-Ski mice. These results suggest that the Ski phenotype involves attenuated lipogenesis, decreased myostatin signalling, coupled to increased myogenesis and fatty acid oxidation. CONCLUSION Ski regulates several genetic programs and signalling pathways that regulate skeletal muscle and adipose mass to influence body composition development, suggesting that Ski may have a role in risk for obesity and metabolic disease.
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Deheuninck J, Luo K. Ski and SnoN, potent negative regulators of TGF-beta signaling. Cell Res 2009; 19:47-57. [PMID: 19114989 DOI: 10.1038/cr.2008.324] [Citation(s) in RCA: 201] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Ski and the closely related SnoN were discovered as oncogenes by their ability to transform chicken embryo fibroblasts upon overexpression. While elevated expressions of Ski and SnoN have also been reported in many human cancer cells and tissues, consistent with their pro-oncogenic activity, emerging evidence also suggests a potential anti-oncogenic activity for both. In addition, Ski and SnoN have been implicated in regulation of cell differentiation, especially in the muscle and neuronal lineages. Multiple cellular partners of Ski and SnoN have been identified in an effort to understand the molecular mechanisms underlying the complex roles of Ski and SnoN. In this review, we summarize recent findings on the biological functions of Ski and SnoN, their mechanisms of action and how their levels of expression are regulated.
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Affiliation(s)
- Julien Deheuninck
- UC Berkeley, Department of Molecular and Cellular Biology, 16 Barker Hall, MC3204, Berkeley, CA 94720, USA
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Zhang H, Stavnezer E. Ski regulates muscle terminal differentiation by transcriptional activation of Myog in a complex with Six1 and Eya3. J Biol Chem 2008; 284:2867-2879. [PMID: 19008232 DOI: 10.1074/jbc.m807526200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Overexpression of the Ski pro-oncogene has been shown to induce myogenesis in non-muscle cells, to promote muscle hypertrophy in postnatal mice, and to activate transcription of muscle-specific genes. However, the precise role of Ski in muscle cell differentiation and its underlying molecular mechanism are not fully understood. To elucidate the involvement of Ski in muscle terminal differentiation, two retroviral systems were used to achieve conditional overexpression or knockdown of Ski in satellite cell-derived C2C12 myoblasts. We found that enforced expression of Ski promoted differentiation, whereas loss of Ski severely impaired it. Compromised terminal differentiation in the absence of Ski was likely because of the failure to induce myogenin (Myog) and p21 despite normal expression of MyoD. Chromatin immunoprecipitation and transcriptional reporter experiments showed that Ski occupied the endogenous Myog regulatory region and activated transcription from the Myog regulatory region upon differentiation. Transactivation of Myog was largely dependent on a MEF3 site bound by Six1, not on the binding site of MyoD or MEF2. Activation of the MEF3 site required direct interaction of Ski with Six1 and Eya3 mediated by the evolutionarily conserved Dachshund homology domain of Ski. Our results indicate that Ski is necessary for muscle terminal differentiation and that it exerts this role, at least in part, through its association with Six1 and Eya3 to regulate the Myog transcription.
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Affiliation(s)
- Hong Zhang
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Ed Stavnezer
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106.
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Le Scolan E, Zhu Q, Wang L, Bandyopadhyay A, Javelaud D, Mauviel A, Sun L, Luo K. Transforming growth factor-beta suppresses the ability of Ski to inhibit tumor metastasis by inducing its degradation. Cancer Res 2008; 68:3277-85. [PMID: 18451154 DOI: 10.1158/0008-5472.can-07-6793] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
c-Ski is an important corepressor of transforming growth factor-beta (TGF-beta) signaling through its ability to bind to and repress the activity of the Smad proteins. It was initially identified as an oncogene that promotes anchorage-independent growth of chicken and quail embryo fibroblasts when overexpressed. Although increased Ski expression is detected in many human cancer cells, the roles of Ski in mammalian carcinogenesis have yet to be defined. Here, we report that reducing Ski expression in breast and lung cancer cells does not affect tumor growth but enhances tumor metastasis in vivo. Thus, in these cells, Ski plays an antitumorigenic role. We also showed that TGF-beta, a cytokine that is often highly expressed in metastatic tumors, induces Ski degradation through the ubiquitin-dependent proteasome in malignant human cancer cells. On TGF-beta treatment, the E3 ubiquitin ligase Arkadia mediates degradation of Ski in a Smad-dependent manner. Although Arkadia interacts with Ski in the absence of TGF-beta, binding of phosphorylated Smad2 or Smad3 to Ski is required to induce efficient degradation of Ski by Arkadia. Our results suggest that the ability of TGF-beta to induce degradation of Ski could be an additional mechanism contributing to its protumorigenic activity.
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Affiliation(s)
- Erwan Le Scolan
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
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Kobayashi N, Goto K, Horiguchi K, Nagata M, Kawata M, Miyazawa K, Saitoh M, Miyazono K. c-Ski activates MyoD in the nucleus of myoblastic cells through suppression of histone deacetylases. Genes Cells 2007; 12:375-85. [PMID: 17352741 DOI: 10.1111/j.1365-2443.2007.01052.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
c-Ski, originally identified as an oncogene product, induces myogenic differentiation in nonmyogenic fibroblasts through transcriptional activation of muscle regulatory factors. Although c-Ski does not bind to DNA directly, it binds to DNA through interaction with Smad proteins and regulates signaling activities of transforming growth factor-beta (TGF-beta). In the present study, we show that c-Ski activates the myogenin promoter independently of regulation of endogenous TGF-beta signaling. Expression of myogenin is regulated by a transcription factor complex containing proteins of the MyoD family and the myocyte enhancer factor 2 (MEF2) family. c-Ski acts on the MyoD-MEF2 complex and modulates the activity of MyoD in myogenin promoter regulation. Interestingly, histone deacetylase (HDAC) inhibitors up-regulated basal activity of transcription from a MyoD-responsive reporter, although c-Ski failed to further augment this transcription in the presence of HDAC inhibitors. c-Ski is observed both in the cytoplasm and in the nucleus, but its nuclear localization is required for myogenic differentiation. We conclude that c-Ski induces myogenic differentiation through acting on MyoD and inhibiting HDAC activity in the nucleus of myogenic cells.
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Affiliation(s)
- Norihiko Kobayashi
- Department of Molecular Pathology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Wu Z, Nagano I, Boonmars T, Takahashi Y. Involvement of the c-Ski oncoprotein in cell cycle arrest and transformation during nurse cell formation after Trichinella spiralis infection. Int J Parasitol 2006; 36:1159-66. [PMID: 16890942 DOI: 10.1016/j.ijpara.2006.05.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 04/27/2006] [Accepted: 05/16/2006] [Indexed: 12/13/2022]
Abstract
The role of c-Ski, an oncoprotein encoded by the oncogene, c-ski, in Trichinella spiralis-infected muscle tissues during nurse cell formation, was investigated by following the expression kinetics and distribution of c-Ski (both protein and mRNA) in the infected muscle cell, as well as the expression kinetics of the transforming growth factor beta (TGF-beta) signaling pathway factor genes (TGF-beta, Smad2 and Smad4) which cooperate with c-Ski. Immunohistochemical analysis using an anti-c-Ski antibody indicated that in the early stages of infection (13 and 18 days post-infection (p.i.)) the increased expression of the c-Ski protein was limited to the eosinophilic cytoplasm and not the enlarged nuclei or basophilic cytoplasm. At a later stage of infection (23 and 28 days p.i.) the c-Ski protein was limited to the enlarged nuclei in the basophilic cytoplasm, rather than the eosinophilic cytoplasm. At 48 days p.i., the c-Ski protein was barely detectable. Real-time PCR analysis showed that expression of the c-ski gene increased from 13 days p.i., reached a peak at 23-28 days p.i. and then decreased to a low level by 48 days p.i. Expression kinetics for the TGF-beta signaling pathway factor genes (TGF-beta, Smad2 and Smad4) were similar to that of c-ski. These findings provide evidence that the c-Ski protein is involved in nurse cell formation through the TGF-beta signaling pathway process in the host cell nucleus.
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Affiliation(s)
- Z Wu
- Department of Parasitology, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1194, Japan
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Bruusgaard JC, Brack AS, Hughes SM, Gundersen K. Muscle hypertrophy induced by the Ski protein: cyto-architecture and ultrastructure. ACTA ACUST UNITED AC 2006; 185:141-9. [PMID: 16168008 DOI: 10.1111/j.1365-201x.2005.01462.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Transgenic mice overexpressing the c-ski proto-oncogene driven by the MSV promoter undergo muscle hypertrophy, most notably fast fibres of the lower limb. This hypertrophy is not accompanied by a correspondingly large increase in force, and individual skinned muscle fibres exhibit a 30% reduction in force per cross-sectional area. In this respect, the MSV ski model is different from most other hypertrophy models and we here aim at describing the mechanisms for the reduced specific force. METHODS Cyoarchitecture and ultrastructure of muscle fibres from the fast extensor digitorum longus muscle of 2-3 months old MSV ski mice was studied. In addition to electron microscopy, we used in vivo intracellular injections of myonuclear dye to investigate nuclear number. RESULTS The number of nuclei did not increase in proportion to size, and consequently nuclear domains were increased compared with wild type. The fraction of the cytoplasm occupied by contractile material was reduced by 18%. In addition we observed poor intracellular alignment of Z-discs. Such staggering has been reported to reduce force in desmin deficient mice, but the amount and distribution of desmin in the MSV ski mice seemed normal. The mitochondria of MSV ski mice showed irregularly spaced cristae that were frequently disrupted. CONCLUSION The reduction in specific force observed in MSV ski mice could be explained by a reduced fraction of contractile material and reduced transversal mechanical coupling. The ultrastructural abnormalities could be related to an increase in nuclear domains.
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Affiliation(s)
- J C Bruusgaard
- Department of Molecular Biosciences, University of Oslo, Blindern, Oslo, Norway
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Kim H, Yamanouchi K, Nishihara M. Expression of Ski in the Granulosa Cells of Atretic Follicles in the Rat Ovary. J Reprod Dev 2006; 52:715-21. [PMID: 16926528 DOI: 10.1262/jrd.18051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of the present study was to locate Ski protein, a product of cellular protooncogene c-ski, in rat ovaries in order to predict the possible involvement of Ski in follicular development and atresia. First, expression of c-ski mRNA in the ovaries of adult female rats was confirmed by RT-PCR. Then, ovaries obtained on the day of estrus were subjected to immunohistochemical analysis for Ski and proliferating cell nuclear antigen (PCNA) in combination with terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL). Ski was expressed in granulosa cells that were positive for TUNEL, but negative for PCNA, regardless of the size of follicles. Expression of Ski in TUNEL-positive granulosa cells, but not in PCNA-positive granulosa cells, was also verified in immature hypophysectomized rats having a single generation of developing and atretic follicles by treatment with equine chorionic gonadotropin. These results indicate that Ski is profoundly expressed in the granulosa cells of atretic follicles, but not in growing follicles, and suggests that Ski plays a role in apoptosis of granulosa cells during follicular atresia.
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Affiliation(s)
- Hyun Kim
- Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Japan
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16
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Kronenwett R, Butterweck U, Steidl U, Kliszewski S, Neumann F, Bork S, Blanco ED, Roes N, Gräf T, Brors B, Eils R, Maercker C, Kobbe G, Gattermann N, Haas R. Distinct molecular phenotype of malignant CD34(+) hematopoietic stem and progenitor cells in chronic myelogenous leukemia. Oncogene 2005; 24:5313-24. [PMID: 15806158 DOI: 10.1038/sj.onc.1208596] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chronic myelogenous leukemia (CML) is a malignant disorder of the hematopoietic stem cell characterized by the BCR-ABL oncogene. We examined gene expression profiles of highly enriched CD34(+) hematopoietic stem and progenitor cells from patients with CML in chronic phase using cDNA arrays covering 1.185 genes. Comparing CML CD34(+) cells with normal CD34(+) cells, we found 158 genes which were significantly differentially expressed. Gene expression patterns reflected BCR-ABL-induced functional alterations such as increased cell-cycle and proteasome activity. Detoxification enzymes and DNA repair proteins were downregulated in CML CD34(+) cells, which might contribute to genetic instability. Decreased expression of junction plakoglobulin and CXC chemokine receptor 4 (CXCR-4) might facilitate the release of immature precursors from bone marrow in CML. GATA-2 was upregulated in CML CD34(+) cells, suggesting an increased self-renewal in comparison with normal CD34(+) cells. Moreover, we found upregulation of the proto-oncogene SKI and of receptors for neuromediators such as opioid mu1 receptor, GABA B receptor, adenosine A1 receptor, orexin 1 and 2 receptors and corticotropine-releasing hormone receptor. Treatment of CML progenitor cells with the selective adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) resulted in a dose-dependent significant inhibition of clonogenic growth by 40% at a concentration of 10(-5) M, which could be reversed by the equimolar addition of the receptor agonist 2-chloro-N6-cyclopentyladenosine (P<0.05). The incubation of normal progenitor cells with DPCPX resulted in an inhibition of clonogenic growth to a significantly lesser extent in comparison with CML cells (P<0.05), suggesting that the adenosine A1 receptor is of functional relevance in CML hematopoietic progenitor cells.
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Affiliation(s)
- Ralf Kronenwett
- Department of Hematology, Oncology and Clinical Immunology, Heinrich Heine University Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany.
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17
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Abstract
Ski and SnoN are unique proto-oncoproteins in that they can induce both oncogenic transformation and terminal muscle differentiation when expressed at high levels. Recent studies using in vitro and in vivo approaches have begun to unravel the complex roles of Ski and SnoN in tumorigenesis and embryonic development. The identification of Ski and SnoN as important negative regulators of signal transduction by the transforming growth factor-beta superfamily of cytokines provides a valuable molecular basis for the complex functions of Ski and SnoN.
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Affiliation(s)
- Kunxin Luo
- Life Sciences Division, Lawrence Berkeley National Laboratory and Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, 237 Hildebrand Hall, Mail code 3206, Berkeley, CA 94720-3206, USA.
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18
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Abstract
The bone morphogenetic proteins (BMPs) play important roles in the regulation of multiple aspects of vertebrate development. BMPs signal through the cell surface receptors and downstream Smad molecules. Upon stimulation with BMP, Smad1, Smad5, and Smad8 are phosphorylated by the activated BMP receptors, form a complex with Smad4, and translocate into the nucleus, where they regulate the expression of BMP target genes. The activity of this signal pathway can be modulated both by extracellular factors that regulate the binding of BMPs to the receptor and by intracellular proteins that interact with the Smad proteins. We have shown that Ski is an important negative regulator of the Smad proteins. Ski can bind to the BMP-Smad protein complexes in response to BMP and repress their ability to activate BMP target genes through disruption of a functional Smad complex and through recruitment of transcriptional co-repressors. The antagonism of BMP signaling by Ski results in neural specification in Xenopus embryos and inhibition of osteoblast differentiation in mouse bone-marrow stromal progenitor cells. This ability to modulate BMP signaling by Ski may play an important role in the regulation of craniofacial, neuronal, and skeletal muscle development.
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Affiliation(s)
- Kunxin Luo
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3206, USA.
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19
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Costelli P, Carbó N, Busquets S, López-Soriano FJ, Baccino FM, Argilés JM. Reduced protein degradation rates and low expression of proteolytic systems support skeletal muscle hypertrophy in transgenic mice overexpressing the c-ski oncogene. Cancer Lett 2003; 200:153-60. [PMID: 14568169 DOI: 10.1016/s0304-3835(03)00415-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have investigated the protein turnover modulations involved in the hypertrophic muscle phenotype of c-ski overexpressing transgenic mice. In these animals, the body weight is increased and all the muscles examined show a definite hypertrophy. The protein degradation rate is significantly reduced in the fast twitch muscles of c-ski transgenic animals with respect to controls; in contrast, there are no detectable differences in the synthesis rates. The down-regulation of protein breakdown is paralleled by decreased expression of genes belonging to the lysosomal as well as to the ATP-ubiquitin-dependent proteolytic pathways.
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Affiliation(s)
- Paola Costelli
- Dipartimento di Medicina ed Oncologia Sperimentale, Università di Torino, Torino, Italy
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20
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Soeta C, Suzuki M, Suzuki S, Naito K, Tachi C, Tojo H. Possible role for the c-ski gene in the proliferation of myogenic cells in regenerating skeletal muscles of rats. Dev Growth Differ 2001; 43:155-64. [PMID: 11284965 DOI: 10.1046/j.1440-169x.2001.00565.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Skeletal muscle regeneration after injury involves various processes, such as infiltration by inflammatory cells, the proliferation of satellite cells and fusion to myotubes. The c-ski nuclear protein has been implicated in the control of cell proliferation and/or terminal differentiation in the growth of skeletal muscle. However, there have been no reports concerning the involution of c-ski in the regeneration of injured skeletal muscle in mammals. A possible role for c-ski in the proliferation of myogenic cells in rat skeletal muscle during regeneration has been investigated with the assistance of in vitro experiments with L6 skeletal muscle cells. The expression levels of c-ski mRNA in regenerating tissues increased to approximately threefold that of intact tissues at 2 days after injury and decreased to normal levels at 2 weeks after injury. Many mononuclear cells among the Ski-positive cells expressed desmin and proliferating cell nuclear antigen, indicating that Ski-producing cells include the proliferating myogenic cells. The proliferation of L6 cells was significantly retarded by expression of the antisense ski gene. The results of the present study reveal that the c-ski gene plays an important role in the proliferation of myogenic cells in the regeneration of injured skeletal muscle.
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Affiliation(s)
- C Soeta
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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21
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Abstract
Transforming growth factor-beta is a potent inhibitor of epithelial cell proliferation. Proteins involved in TGF-beta signaling are bona fide tumor suppressors and many tumor cells acquire the ability to escape TGF-beta growth inhibition through the loss of key signaling transducers in the pathway or through the activation of oncogenes. Recent studies indicate that there is a specific connection between the TGF-beta signaling pathway and the Ski/SnoN family of oncoproteins. We summarize evidence that Ski and SnoN directly associate with Smad proteins and block the ability of the Smads to activate expression of many if not all TGF-beta-responsive genes. This appears to cause abrogation of TGF-beta growth inhibition in epithelial cells.
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Affiliation(s)
- X Liu
- Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, CO 80309, USA
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22
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Wang W, Mariani FV, Harland RM, Luo K. Ski represses bone morphogenic protein signaling in Xenopus and mammalian cells. Proc Natl Acad Sci U S A 2000; 97:14394-9. [PMID: 11121043 PMCID: PMC18929 DOI: 10.1073/pnas.97.26.14394] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The bone morphogenic proteins (BMPs) play important roles in vertebrate development. In Xenopus, BMPs act as epidermal inducers and also as negative regulators of neurogenesis. Antagonism of BMP signaling results in neuralization. BMPs signal through the cell-surface receptors and downstream Smad molecules. Upon stimulation with BMP, Smad1, Smad5, and Smad8 are phosphorylated by the activated BMP receptors, form a complex with Smad4, and translocate into the nucleus, where they regulate the expression of BMP target genes. Here, we show that the Ski oncoprotein can block BMP signaling and the expression of BMP-responsive genes in both Xenopus and mammalian cells by directly interacting with and repressing the activity of BMP-specific Smad complexes. This ability to antagonize BMP signaling results in neuralization by Ski in the Xenopus embryo and blocking of osteoblast differentiation of murine W-20-17 cells. Thus, Ski is able to repress the activity of all receptor-associated Smads and may regulate vertebrate development by modulating the signaling activity of transforming growth factor-beta family members.
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Affiliation(s)
- W Wang
- Life Sciences Division, Lawrence Berkeley National Laboratory, and Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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23
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Abstract
Isoform diversity in striated muscle is largely controlled at the level of transcription. In this review we will concentrate on studies concerning transcriptional regulation of the alkali myosin light chain 1F/3F gene. Uncoupled activity of the MLC1F and 3F promoters, together with complex patterns of transcription in developing skeletal and cardiac muscle, combine to make analysis of this gene particularly intriguing. In vitro and transgenic studies of MLC1F/3F regulatory elements have revealed an array of cis-acting modules that each drive a subset of the expression pattern of the two promoters. These cis-acting regulatory modules, including the MLC1F and 3F promoter regions and two skeletal muscle enhancers, control tissue-specificity, cell or fibre-type specificity, and the spatiotemporal regulation of gene expression, including positional information. How each of these regulatory modules acts and how their individual activites are integrated to coordinate transcription at this locus are discussed.
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Affiliation(s)
- R G Kelly
- CNRS URA 1947, Département de Biologie Moléculaire, Institut Pasteur, 75724 Paris Cedex 15, France
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24
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Kaufman CD, Martínez-Rodriguez G, Hackett PB. Ectopic expression of c-ski disrupts gastrulation and neural patterning in zebrafish. Mech Dev 2000; 95:147-62. [PMID: 10906458 DOI: 10.1016/s0925-4773(00)00351-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The c-ski proto-oncogene encodes a transcriptional regulator that has been implicated in the development of different tissues at different times during vertebrate development. We identified two novel paralogues of the c-ski gene family, skiA and skiB in zebrafish (Danio rerio). The skiA protein is maternal and ubiquitous while skiB is zygotic. Overexpression of SkiA or SkiB disrupted gastrulation and resulted in a dorsalized phenotype. In situ analyses suggested that overexpression of Ski leads to a slight expansion of dorsal-axial mesoderm, diminishment or loss of ventral mesoderm and radialization of dorsal neuroectoderm. The dorsalized phenotype could be rescued by the ventral specifying factor, BMP4. These results provide evidence that Ski proteins participate in dorsal-ventral specification of both neuroectoderm and mesoderm.
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Affiliation(s)
- C D Kaufman
- Department of Genetics, Cell Biology and Development, University of Minnesota, 1445 Gortner Avenue, St. Paul, MN 55108-1095, USA
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25
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Sutrave P, Leferovich JM, Kelly AM, Hughes SH. The induction of skeletal muscle hypertrophy by a ski transgene is promoter-dependent. Gene 2000; 241:107-16. [PMID: 10607904 DOI: 10.1016/s0378-1119(99)00461-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The chicken c-ski gene expresses at least three alternatively spliced messages. Transgenic mice expressing proteins from cDNA corresponding to two of these messages (FB27 and FB29) under the control of a murine sarcoma virus (MSV) long terminal repeat (LTR) express the transgene in skeletal muscle and develop a muscular phenotype. Both a biologically active form of c-ski and the MSV LTR are required for the development of the muscular phenotype. The normal c-ski gene linked to two other tissue-specific promoters failed to induce muscle growth in transgenic mice, as did an inactive mutant of c-ski expressed under the control of the MSV LTR.
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Affiliation(s)
- P Sutrave
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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26
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YAMANOUCHI K, SOETA C, NAITO K, TOJO H. Progesterone Pretreatment Inhibits the Expression of c-ski mRNA and Epithelial Cell Proliferation Induced by Estrogen in the Rat Uterus. J Reprod Dev 2000. [DOI: 10.1262/jrd.46.257] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Keitaro YAMANOUCHI
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Chie SOETA
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kunihiko NAITO
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hideaki TOJO
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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27
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Abstract
Two classes of tilapia c-ski cDNA (accession nos. AJ012011, AJ012012), designated as tski1 and tski2, respectively encoded a 687 and a 714 AA protein and shared a 57% AA identity. Comparison with the Ski proteins of chickens, humans and Xenopus, tilapia TSki polypeptides shared a 60, 57, and 57% (TSki1) and 67, 63, and 61% (TSki2) AA identity, respectively. The most and the least abundant c-ski mRNAs are located in the brain and the skeletal muscle, respectively. Both tski1 and tski2 were widely expressed in the adult tissues examined, but tski2 transcripts were at higher levels except in the ovary and oocytes: tski1 transcripts were predominant in the ovary, whereas tski2 transcripts were predominant in the testes. In the oocytes, the tski1 mRNA was a maternally-inherited stockpile that subsequently was degraded, so that the expression ratio of tski1 to tski2 transcripts declined gradually as the fish developed from oocyte to 4-cm fry. Mol. Reprod. Dev. 54:223- 231.
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Affiliation(s)
- C J Huang
- Institute of Fisheries Science, National Taiwan University, Taipei, Taiwan
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28
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Yamanouchi K, Soeta C, Harada R, Naito K, Tojo H. Endometrial expression of cellular protooncogene c-ski and its regulation by estradiol-17beta. FEBS Lett 1999; 449:273-6. [PMID: 10338147 DOI: 10.1016/s0014-5793(99)00424-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The expression of the cellular protooncogene c-ski was examined in the rat uterus. In situ hybridization revealed that c-ski mRNA was expressed in the uterus of the adult rat on the day of estrous and localized mainly in the luminal and glandular epithelia. To test the possibility that the expression of c-ski mRNA is induced by estrogen, rats were ovariectomized and estradiol-17beta (E2) was injected. The expression of c-ski mRNA was upregulated 3 h after E2 treatment, reaching the highest level at 6 h and this persisted until 24 h; the E2-induced expression of c-ski mRNA was restricted to the luminal and glandular epithelia. These results suggest that the c-ski gene plays a role in uterine epithelial cell proliferation and mediates the proliferative action of E2.
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Affiliation(s)
- K Yamanouchi
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan.
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29
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Amaravadi LS, Neff AW, Sleeman JP, Smith RC. Autonomous neural axis formation by ectopic expression of the protooncogene c-ski. Dev Biol 1997; 192:392-404. [PMID: 9441676 DOI: 10.1006/dbio.1997.8780] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The ski oncogene was originally isolated as an avian retroviral gene with the ability to induce quail embryonic cells to differentiate into muscle. Mice containing a chicken c-ski transgene exhibit postnatal hypertrophy of skeletal muscle. Xenopus ski (Xski) protein is maternal and present throughout early development. We show that overexpression of Xski RNA in Xenopus embryos results in the cell-autonomous induction of secondary neural axis formation. Injection of Xski RNA into prospective endodermal cells resulted in the formation of an ectopic neural tube-like structure and cells derived from the injected blastomeres populated the spinal cord. Injected Xski RNA was able to induce neural-specific gene expression directly in ectodermal explants in the absence of the expression of mesodermal markers. The widespread distribution of ski protein in the early gastrula embryo including the dorsal animal region supports a role for ski in neural axis formation in vivo.
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Affiliation(s)
- L S Amaravadi
- Lilly Research Laboratories, Division of Eli Lilly and Company, Greenfield, Indiana 46140, USA
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30
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Ichikawa K, Nagase T, Ishii S, Asano A, Mimura N. Trans-regulation of myogenin promoter/enhancer activity by c-ski during skeletal-muscle differentiation: the C-terminus of the c-Ski protein is essential for transcriptional regulatory activity in myotubes. Biochem J 1997; 328 ( Pt 2):607-13. [PMID: 9371722 PMCID: PMC1218962 DOI: 10.1042/bj3280607] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
c-ski gene product is a nuclear protein with myogenesis-promoting and transforming activities. We have analysed the effects of c-ski transfection on the promoter/enhancer activity of the upstream region of the myogenin gene during in vitro myogenesis using CAT reporter assay. When co-transfected with c-ski into myogenic C2C12 cells, promoter/enhancer activity was efficiently suppressed in proliferating cells, but the myogenesis-induced increase in activity was potentiated approximately ten times more (150-fold in the ski-transfected cells) than the ordinary increase (12-fold in the mock) 48 h after induction of differentiation. In non-myogenic 10T1/2 cells, c-ski transfection caused persistent suppression of promoter/enhancer activity in both proliferating and growth-arrested (i.e. myogenesis-inducing) conditions. Thus the ski-dependent potentiation of myogenin gene transcriptional activity appears to be specific for myogenesis. The C-terminal region (amino acids 595-663) of the c-Ski protein was essential for the potentiating activity in myotubes. Other members of the ski-gene family, snoN and snoA, were ineffective in transactivation, possibly because of the defect in the corresponding C-terminal region. c-Ski protein underwent a mobility shift on SDS/PAGE after in vitro myogenesis which may explain the conversion of the activity from suppressive in myoblasts to potentiating in myotubes. Deletion analysis of the upstream region of the myogenin gene revealed that a responsive element to c-ski in myotubes is located at a distinct site upstream of the basal promoter/enhancer region.
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Affiliation(s)
- K Ichikawa
- Institute for Protein Research, Osaka University, 3-2, Yamadaoka, Suita, Osaka 565, Japan and AGENE Research Institute, 200 Kajiwara, Kamakura, Kanagawa 247, Japan
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31
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Berk M, Desai SY, Heyman HC, Colmenares C. Mice lacking the ski proto-oncogene have defects in neurulation, craniofacial, patterning, and skeletal muscle development. Genes Dev 1997; 11:2029-39. [PMID: 9284043 PMCID: PMC316447 DOI: 10.1101/gad.11.16.2029] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The c-ski proto-oncogene has been implicated in the control of cell growth and skeletal muscle differentiation. To determine its normal functions in vivo, we have disrupted the mouse c-ski gene. Our results show a novel role for ski in the morphogenesis of craniofacial structures and the central nervous system, and confirm its proposed function as a player in skeletal muscle development. Homozygous mutant mice show perinatal lethality resulting from exencephaly, a defect caused by failed closure of the cranial neural tube during neurulation. The timing of the neural tube defect in ski -/- embryos coincides with excessive apoptosis in the cranial neuroepithelium, as well as in the cranial mesenchyme. Homozygous ski mutants also exhibit a dramatic reduction in skeletal muscle mass, consistent with a defect in expansion of a myogenic precursor population. Nestin is an intermediate filament expressed in highly proliferative neuroepithelial stem cells and in myogenic precursors. Interestingly, we find decreased nestin expression in both the cranial neural tube and the somites of ski -/- embryos, compared with their normal littermates, but no reduction of nestin in the caudal neural tube. These results are consistent with a model in which ski activities are required for the successful expansion of a subset of precursors in the neuroepithelial or skeletal muscle lineages.
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Affiliation(s)
- M Berk
- Department of Cancer Biology, Research Institute, The Cleveland Clinic Foundation, Ohio 44195, USA
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32
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Pearson-White S, Crittenden R. Proto-oncogene Sno expression, alternative isoforms and immediate early serum response. Nucleic Acids Res 1997; 25:2930-7. [PMID: 9207045 PMCID: PMC146803 DOI: 10.1093/nar/25.14.2930] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The mouse Sno gene, a Ski proto-oncogene homolog, expresses two isoforms, SnoN and SnoN2 (also called sno -dE3), which differ from each other in a location downstream from the site of alternative splicing previously described in the human SNO gene. SnoN2 is missing a 138 nt coding segment present in mouse SnoN and human SNON . We have cloned and sequenced the human ortholog of mouse SnoN2 , the existence of which was predicted from conservation of the alternative splice donor site that produces the SnoN2 isoform. Mouse SnoN2 and SnoN are expressed throughout embryonic development, in neonatal muscle and in many adult tissues. SnoN2 is the major species in most tissues, but SnoN and SnoN2 are expressed at approximately equal levels in brain. In human tissues, SNON2 is the less abundantly expressed isoform. Expression of mouse SnoN and SnoN2 mRNAs is induced with immediate early kinetics upon serum stimulation of quiescent fibroblasts, even in the presence of the protein synthesis inhibitor cycloheximide, while Ski is not. Interestingly, although both isoforms of Sno are induced, SnoN2 induction is much higher than SnoN . These data are consistent with a role for Sno in the response to proliferation stimuli.
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Affiliation(s)
- S Pearson-White
- Department of Microbiology, Box 441, University of Virginia Medical Center, Charlottesville, VA 22908, USA.
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33
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YAMANOUCHI K, KANO K, SOETA C, HASEGAWA T, ISHIDA N, MUKOYAMA H, TOJO H, TACHI C. Studies on Expression of the c-ski Gene in Equine (Thoroughbred) Tissues. J Equine Sci 1997. [DOI: 10.1294/jes.8.13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Affiliation(s)
- Keitaro YAMANOUCHI
- Laboratory of Applied Genetics, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113, Japan
| | - Kiyoshi KANO
- Laboratory of Applied Genetics, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113, Japan
| | - Chie SOETA
- Laboratory of Applied Genetics, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113, Japan
| | - Telhisa HASEGAWA
- Laboratory of Molecular and Cellular Biology, Equine Research Institute, Japan Racing Association, Utsunomiya 320, Japan
| | - Nobushige ISHIDA
- Laboratory of Molecular and Cellular Biology, Equine Research Institute, Japan Racing Association, Utsunomiya 320, Japan
| | - Harutaka MUKOYAMA
- Laboratory of Molecular and Cellular Biology, Equine Research Institute, Japan Racing Association, Utsunomiya 320, Japan
| | - Hideaki TOJO
- Laboratory of Applied Genetics, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113, Japan
| | - Chikashi TACHI
- Laboratory of Applied Genetics, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113, Japan
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34
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Pelzer T, Lyons GE, Kim S, Moreadith RW. Cloning and characterization of the murine homolog of the sno proto-oncogene reveals a novel splice variant. Dev Dyn 1996; 205:114-25. [PMID: 8834472 DOI: 10.1002/(sici)1097-0177(199602)205:2<114::aid-aja3>3.0.co;2-l] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The cellular function(s) of the SNO protein remain undefined. To gain a better understanding of possible developmental roles of this cellular proto-oncogene, we have cloned two murine sno cDNAs and have investigated their expression patterns in embryonic and postnatal tissues. A single major transcript of 7.5 kb is detected in multiple tissues by Northern blot. However, reverse transcriptase polymerase chain reaction (RT-PCR) and RNAse protection assays revealed a novel splice variant in every tissue examined. Two isoforms, termed sno N and sno-dE3 (dE3, deletion within exon 3), were identified. The sno-dE3 isoform employs a novel 5' splice site located within the coding region of the third exon and deletes potential kinase recognition motifs. Transcripts of both sno isoforms accumulate ubiquitously but are most abundant in the developing central nervous system. The in situ hybridization patterns of sno expression during murine development suggest potential roles in tissues with a high degree of cellular proliferation. Expression in terminally differentiated tissues such as muscle and neurons indicates that SNO may have multiple functional activities.
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Affiliation(s)
- T Pelzer
- Molecular Cardiology Laboratories, University of Texas Southwestern Medical Center, Dallas 75235, USA
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