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Fu L, Liu R, Ma V, Shi YB. Upregulation of proto-oncogene ski by thyroid hormone in the intestine and tail during Xenopus metamorphosis. Gen Comp Endocrinol 2022; 328:114102. [PMID: 35944650 PMCID: PMC9530006 DOI: 10.1016/j.ygcen.2022.114102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 07/31/2022] [Accepted: 08/03/2022] [Indexed: 11/12/2022]
Abstract
Thyroid hormone (T3) is important for adult organ function and vertebrate development, particularly during the postembryonic period when many organs develop/mature into their adult forms. Amphibian metamorphosis is totally dependent on T3 and can be easily manipulated, thus offering a unique opportunity for studying how T3 controls postembryonic development in vertebrates. Numerous early studies have demonstrated that T3 affects frog metamorphosis through T3 receptor (TR)-mediated regulation of T3 response genes, where TR forms a heterodimer with RXR (9-cis retinoic acid receptor) and binds to T3 response elements (TREs) in T3 response genes to regulate their expression. We have previously identified many candidate direct T3 response genes in Xenopus tropicalis tadpole intestine. Among them is the proto-oncogene Ski, which encodes a nuclear protein with complex function in regulating cell fate. We show here that Ski is upregulated in the intestine and tail of premetamorphic tadpoles upon T3 treatment and its expression peaks at stage 62, the climax of metamorphosis. We have further discovered a putative TRE in the first exon that can bind to TR/RXR in vitro and mediate T3 regulation of the promoter in vivo. These data demonstrate that Ski is activated by T3 through TR binding to a TRE in the first exon during Xenopus tropicalis metamorphosis, implicating a role of Ski in regulating cell fate during metamorphosis.
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Affiliation(s)
- Liezhen Fu
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert Liu
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD 20892, USA
| | - Vincent Ma
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD 20892, USA
| | - Yun-Bo Shi
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD 20892, USA.
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2
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Feld C, Sahu P, Frech M, Finkernagel F, Nist A, Stiewe T, Bauer UM, Neubauer A. Combined cistrome and transcriptome analysis of SKI in AML cells identifies SKI as a co-repressor for RUNX1. Nucleic Acids Res 2019; 46:3412-3428. [PMID: 29471413 PMCID: PMC5909421 DOI: 10.1093/nar/gky119] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 02/09/2018] [Indexed: 11/16/2022] Open
Abstract
SKI is a transcriptional co-regulator and overexpressed in various human tumors, for example in acute myeloid leukemia (AML). SKI contributes to the origin and maintenance of the leukemic phenotype. Here, we use ChIP-seq and RNA-seq analysis to identify the epigenetic alterations induced by SKI overexpression in AML cells. We show that approximately two thirds of differentially expressed genes are up-regulated upon SKI deletion, of which >40% harbor SKI binding sites in their proximity, primarily in enhancer regions. Gene ontology analysis reveals that many of the differentially expressed genes are annotated to hematopoietic cell differentiation and inflammatory response, corroborating our finding that SKI contributes to a myeloid differentiation block in HL60 cells. We find that SKI peaks are enriched for RUNX1 consensus motifs, particularly in up-regulated SKI targets upon SKI deletion. RUNX1 ChIP-seq displays that nearly 70% of RUNX1 binding sites overlap with SKI peaks, mainly at enhancer regions. SKI and RUNX1 occupy the same genomic sites and cooperate in gene silencing. Our work demonstrates for the first time the predominant co-repressive function of SKI in AML cells on a genome-wide scale and uncovers the transcription factor RUNX1 as an important mediator of SKI-dependent transcriptional repression.
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Affiliation(s)
- Christine Feld
- Institute of Molecular Biology and Tumor Research (IMT), School of Medicine, Philipps University Marburg, Hans-Meerwein-Str. 2, 35043 Marburg, Germany.,Department of Internal Medicine and Hematology, Oncology and Immunology, Philipps University Marburg, University Hospital Giessen and Marburg, Baldingerstr., 35043 Marburg, Germany
| | - Peeyush Sahu
- Institute of Molecular Biology and Tumor Research (IMT), School of Medicine, Philipps University Marburg, Hans-Meerwein-Str. 2, 35043 Marburg, Germany
| | - Miriam Frech
- Department of Internal Medicine and Hematology, Oncology and Immunology, Philipps University Marburg, University Hospital Giessen and Marburg, Baldingerstr., 35043 Marburg, Germany
| | - Florian Finkernagel
- Institute of Molecular Biology and Tumor Research (IMT), School of Medicine, Philipps University Marburg, Hans-Meerwein-Str. 2, 35043 Marburg, Germany
| | - Andrea Nist
- Genomics Core Facility, Philipps University Marburg, Hans-Meerwein-Str. 3, 35043 Marburg, Germany
| | - Thorsten Stiewe
- Genomics Core Facility, Philipps University Marburg, Hans-Meerwein-Str. 3, 35043 Marburg, Germany.,Institute of Molecular Oncology, Philipps University Marburg, Hans-Meerwein-Str. 3, 35043 Marburg, Germany
| | - Uta-Maria Bauer
- Institute of Molecular Biology and Tumor Research (IMT), School of Medicine, Philipps University Marburg, Hans-Meerwein-Str. 2, 35043 Marburg, Germany
| | - Andreas Neubauer
- Department of Internal Medicine and Hematology, Oncology and Immunology, Philipps University Marburg, University Hospital Giessen and Marburg, Baldingerstr., 35043 Marburg, Germany
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3
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Zeglinski MR, Moghadam AR, Ande SR, Sheikholeslami K, Mokarram P, Sepehri Z, Rokni H, Mohtaram NK, Poorebrahim M, Masoom A, Toback M, Sareen N, Saravanan S, Jassal DS, Hashemi M, Marzban H, Schaafsma D, Singal P, Wigle JT, Czubryt MP, Akbari M, Dixon IM, Ghavami S, Gordon JW, Dhingra S. Myocardial Cell Signaling During the Transition to Heart Failure. Compr Physiol 2018; 9:75-125. [DOI: 10.1002/cphy.c170053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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4
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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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5
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Rivas S, Armisén R, Rojas DA, Maldonado E, Huerta H, Tapia JC, Espinoza J, Colombo A, Michea L, Hayman MJ, Marcelain K. The Ski Protein is Involved in the Transformation Pathway of Aurora Kinase A. J Cell Biochem 2016; 117:334-43. [PMID: 26138431 DOI: 10.1002/jcb.25275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 06/29/2015] [Indexed: 12/19/2022]
Abstract
Oncogenic kinase Aurora A (AURKA) has been found to be overexpresed in several tumors including colorectal, breast, and hematological cancers. Overexpression of AURKA induces centrosome amplification and aneuploidy and it is related with cancer progression and poor prognosis. Here we show that AURKA phosphorylates in vitro the transcripcional co-repressor Ski on aminoacids Ser326 and Ser383. Phosphorylations on these aminoacids decreased Ski protein half-life. Reduced levels of Ski resulted in centrosomes amplification and multipolar spindles formation, same as AURKA overexpressing cells. Importantly, overexpression of Ski wild type, but not S326D and S383D mutants inhibited centrosome amplification and cellular transformation induced by AURKA. Altogether, these results suggest that the Ski protein is a target in the transformation pathway mediated by the AURKA oncogene.
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Affiliation(s)
- Solange Rivas
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Ricardo Armisén
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile.,Centro de Investigación y Tratamiento del Cáncer, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Diego A Rojas
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Edio Maldonado
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Hernán Huerta
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Julio C Tapia
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile.,Centro de Investigación y Tratamiento del Cáncer, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Jaime Espinoza
- Department of Pathology, UC-Center for Investigational Oncology (CITO), School of Medicine, Pontificia Universidad Católica de Chile 8330034, Santiago, Chile
| | - Alicia Colombo
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile.,Centro de Investigación y Tratamiento del Cáncer, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Luis Michea
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile.,Centro de Investigación y Tratamiento del Cáncer, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile.,Millenium Institute of Immunology and Immunotherapy, Santiago, Chile
| | - Michael J Hayman
- Department of Microbiology and Molecular Genetics, Stony Brook University, Stony Brook, New York 11794
| | - Katherine Marcelain
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile.,Centro de Investigación y Tratamiento del Cáncer, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
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6
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Tarapore P, Ying J, Ouyang B, Burke B, Bracken B, Ho SM. Exposure to bisphenol A correlates with early-onset prostate cancer and promotes centrosome amplification and anchorage-independent growth in vitro. PLoS One 2014; 9:e90332. [PMID: 24594937 PMCID: PMC3940879 DOI: 10.1371/journal.pone.0090332] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 01/30/2014] [Indexed: 01/19/2023] Open
Abstract
Human exposure to bisphenol A (BPA) is ubiquitous. Animal studies found that BPA contributes to development of prostate cancer, but human data are scarce. Our study examined the association between urinary BPA levels and Prostate cancer and assessed the effects of BPA on induction of centrosome abnormalities as an underlying mechanism promoting prostate carcinogenesis. The study, involving 60 urology patients, found higher levels of urinary BPA (creatinine-adjusted) in Prostate cancer patients (5.74 µg/g [95% CI; 2.63, 12.51]) than in non-Prostate cancer patients (1.43 µg/g [95% CI; 0.70, 2.88]) (p = 0.012). The difference was even more significant in patients <65 years old. A trend toward a negative association between urinary BPA and serum PSA was observed in Prostate cancer patients but not in non-Prostate cancer patients. In vitro studies examined centrosomal abnormalities, microtubule nucleation, and anchorage-independent growth in four Prostate cancer cell lines (LNCaP, C4-2, 22Rv1, PC-3) and two immortalized normal prostate epithelial cell lines (NPrEC and RWPE-1). Exposure to low doses (0.01–100 nM) of BPA increased the percentage of cells with centrosome amplification two- to eight-fold. Dose responses either peaked or reached the plateaus with 0.1 nM BPA exposure. This low dose also promoted microtubule nucleation and regrowth at centrosomes in RWPE-1 and enhanced anchorage-independent growth in C4-2. These findings suggest that urinary BPA level is an independent prognostic marker in Prostate cancer and that BPA exposure may lower serum PSA levels in Prostate cancer patients. Moreover, disruption of the centrosome duplication cycle by low-dose BPA may contribute to neoplastic transformation of the prostate.
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Affiliation(s)
- Pheruza Tarapore
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- Cincinnati Cancer Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Jun Ying
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Bin Ouyang
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- Cincinnati Cancer Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Barbara Burke
- Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Bruce Bracken
- Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Shuk-Mei Ho
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- Cincinnati Cancer Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- Cincinnati Veteran Affairs Hospital Medical Center, Cincinnati, Ohio, United States of America
- * E-mail:
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7
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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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8
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Nyman T, Trésaugues L, Welin M, Lehtiö L, Flodin S, Persson C, Johansson I, Hammarström M, Nordlund P. The crystal structure of the Dachshund domain of human SnoN reveals flexibility in the putative protein interaction surface. PLoS One 2010; 5:e12907. [PMID: 20957027 PMCID: PMC2944819 DOI: 10.1371/journal.pone.0012907] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 08/30/2010] [Indexed: 11/18/2022] Open
Abstract
The human SnoN is an oncoprotein that interacts with several transcription-regulatory proteins such as the histone-deacetylase, N-CoR containing co-repressor complex and Smad proteins. This study presents the crystal structure of the Dachshund homology domain of human SnoN. The structure reveals a groove composed of conserved residues with characteristic properties of a protein-interaction surface. A comparison of the 12 monomers in the asymmetric unit reveals the presence of two major conformations: an open conformation with a well accessible groove and a tight conformation with a less accessible groove. The variability in the backbone between the open and the tight conformations matches the differences seen in previously determined structures of individual Dachshund homology domains, suggesting a general plasticity within this fold family. The flexibility observed in the putative protein binding groove may enable SnoN to recognize multiple interaction partners.
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Affiliation(s)
- Tomas Nyman
- Structural Genomics Consortium, Karolinska Institutet, Stockholm, Sweden
- * E-mail: (TN); (PN)
| | - Lionel Trésaugues
- Structural Genomics Consortium, Karolinska Institutet, Stockholm, Sweden
| | - Martin Welin
- Structural Genomics Consortium, Karolinska Institutet, Stockholm, Sweden
| | - Lari Lehtiö
- Pharmaceutical Sciences, Department of Biosciences, Åbo Akademi University, Turku, Finland
| | - Susanne Flodin
- Structural Genomics Consortium, Karolinska Institutet, Stockholm, Sweden
| | - Camilla Persson
- Structural Genomics Consortium, Karolinska Institutet, Stockholm, Sweden
| | - Ida Johansson
- Structural Genomics Consortium, Karolinska Institutet, Stockholm, Sweden
| | - Martin Hammarström
- Structural Genomics Consortium, Karolinska Institutet, Stockholm, Sweden
| | - Pär Nordlund
- Structural Genomics Consortium, Karolinska Institutet, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- * E-mail: (TN); (PN)
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9
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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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10
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Ueki N, Zhang L, Hayman MJ, Haymann MJ. Ski can negatively regulates macrophage differentiation through its interaction with PU.1. Oncogene 2007; 27:300-7. [PMID: 17621263 PMCID: PMC2850268 DOI: 10.1038/sj.onc.1210654] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the hematopoietic cell system, the oncoprotein Ski dramatically affects growth and differentiation programs, in some cases leading to malignant leukemia. However, little is known about the interaction partners or signaling pathways involved in the Ski-mediated block of differentiation in hematopoietic cells. Here we show that Ski interacts with PU.1, a lineage-specific transcription factor essential for terminal myeloid differentiation, and thereby represses PU.1-dependent transcriptional activation. Consistent with this, Ski inhibits the biological function of PU.1 to promote myeloid cells to differentiate into macrophage colony-stimulating factor receptor (M-CSFR)-positive macrophages. Using a Ski mutant deficient in PU.1 binding, we demonstrate that Ski-PU.1 interaction is critical for Ski's ability to repress PU.1-dependent transcription and block macrophage differentiation. Furthermore, we provide evidence that Ski-mediated repression of PU.1 is due to Ski's ability to recruit histone deacetylase 3 to PU.1 bound to DNA. Since inactivation of PU.1 is closely related to the development of myeloid leukemia and Ski strongly inhibits PU.1 function, we propose that aberrant Ski expression in certain types of myeloid cell lineages might contribute to leukemogenesis.
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Affiliation(s)
- N Ueki
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
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11
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Ito S, Honma T, Ishida K, Wada N, Sasaoka S, Hosoda M, Nohno T. Differential expression of the human alpha-enolase gene in oral epithelium and squamous cell carcinoma. Cancer Sci 2007; 98:499-505. [PMID: 17284257 PMCID: PMC11159807 DOI: 10.1111/j.1349-7006.2007.00411.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
alpha-Enolase and c-myc promoter binding protein 1 are encoded by a single gene, ENO1, and are synthesized from the same transcript through alternative use of translational start sites. We have investigated the localization of ENO1 gene transcripts detected as proteins with an immunohistochemical method and also as mRNA with an in situ hybridization method on tissue sections of oral epithelium and oral squamous cell carcinoma, and demonstrated the differential distribution of the gene transcripts in normal oral epithelium and oral squamous cell carcinoma in humans. Expression of the ENO1 transcript was detectable in the region from the basal cell layers to the lower granular cell layers. Three patterns of ENO1 localization were observed with immunostaining in the epithelia: cytoplasm, nuclei, and both nuclei and cytoplasm. These patterns were observed randomly within the same specimen. In contrast to normal oral epithelium, ENO1 protein was not detectable in the nuclei of carcinoma cells. Our results indicate that differential subcellular localization of ENO1 products may be closely related to carcinogenesis of the oral epithelium.
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Affiliation(s)
- Satoshi Ito
- Department of Oral Surgery, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan.
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12
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Levy AM, Gilad O, Xia L, Izumiya Y, Choi J, Tsalenko A, Yakhini Z, Witter R, Lee L, Cardona CJ, Kung HJ. Marek's disease virus Meq transforms chicken cells via the v-Jun transcriptional cascade: a converging transforming pathway for avian oncoviruses. Proc Natl Acad Sci U S A 2005; 102:14831-6. [PMID: 16203997 PMCID: PMC1253582 DOI: 10.1073/pnas.0506849102] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Marek's disease virus (MDV) is a highly pathogenic and oncogenic herpesvirus of chickens. MDV encodes a basic leucine zipper (bZIP) protein, Meq (MDV EcoQ). The bZIP domain of Meq shares homology with Jun/Fos, whereas the transactivation/repressor domain is entirely different. Increasing evidence suggests that Meq is the oncoprotein of MDV. Direct evidence that Meq transforms chicken cells and the underlying mechanism, however, remain completely unknown. Taking advantage of the DF-1 chicken embryo fibroblast transformation system, a well established model for studying avian sarcoma and leukemia oncogenes, we probed the transformation properties and pathways of Meq. We found that Meq transforms DF-1, with a cell morphology akin to v-Jun and v-Ski transformed cells, and protects DF-1 from apoptosis, and the transformed cells are tumorigenic in chorioallantoic membrane assay. Significantly, using microarray and RT-PCR analyses, we have identified up-regulated genes such as JTAP-1, JAC, and HB-EGF, which belong to the v-Jun transforming pathway. In addition, c-Jun was found to form stable dimers with Meq and colocalize with it in the transformed cells. RNA interference to Meq and c-Jun down-modulated the expression of these genes and reduced the growth of the transformed DF-1, suggesting that Meq transforms chicken cells by pirating the Jun pathway. These data suggest that avian herpesvirus and retrovirus oncogenes use a similar strategy in transformation and oncogenesis.
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Affiliation(s)
- Alon M Levy
- Department of Biological Chemistry, School of Medicine, University of California, Davis, CA 95616, USA
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13
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Ueki N, Zhang L, Hayman MJ. Ski negatively regulates erythroid differentiation through its interaction with GATA1. Mol Cell Biol 2005; 24:10118-25. [PMID: 15542823 PMCID: PMC529047 DOI: 10.1128/mcb.24.23.10118-10125.2004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Ski oncoprotein dramatically affects cell growth, differentiation, and/or survival. Recently, Ski was shown to act in distinct signaling pathways including those involving nuclear receptors, transforming growth factor beta, and tumor suppressors. These divergent roles of Ski are probably dependent on Ski's capacity to bind multiple partners with disparate functions. In particular, Ski alters the growth and differentiation program of erythroid progenitor cells, leading to malignant leukemia. However, the mechanism underlying this important effect has remained elusive. Here we show that Ski interacts with GATA1, a transcription factor essential in erythropoiesis. Using a Ski mutant deficient in GATA1 binding, we show that this Ski-GATA1 interaction is critical for Ski's ability to repress GATA1-mediated transcription and block erythroid differentiation. Furthermore, the repression of GATA1-mediated transcription involves Ski's ability to block DNA binding of GATA1. This finding is in marked contrast to those in previous reports on the mechanism of repression by Ski, which have described a model involving the recruitment of corepressors into DNA-bound transcription complexes. We propose that Ski cooperates in the process of transformation in erythroid cells by interfering with GATA1 function, thereby contributing to erythroleukemia.
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Affiliation(s)
- Nobuhide Ueki
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5222, USA
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14
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MacDonald PN, Dowd DR, Zhang C, Gu C. Emerging insights into the coactivator role of NCoA62/SKIP in Vitamin D-mediated transcription. J Steroid Biochem Mol Biol 2004; 89-90:179-86. [PMID: 15225769 DOI: 10.1016/j.jsbmb.2004.03.097] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
NCoA62/SKIP was discovered as a nuclear protein that interacts with the Vitamin D receptor (VDR) and the SKI oncoprotein. NCoA62/SKIP expresses properties consistent with other nuclear receptor transcriptional coactivator proteins. For example, NCoA62/SKIP interacts selectively with the VDR-RXR heterodimer, it forms a ternary complex with liganded VDR and steroid receptor coactivator (SRC) proteins, and it synergizes with SRCs to augment 1,25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)]- and VDR-activated transcription. Chromatin immunoprecipitation studies show that NCoA62/SKIP is recruited in a 1,25-(OH)(2)D(3)-dependent manner to native Vitamin D responsive gene promoters and it enters these promoter complexes after VDR and SRC entry. This suggests that NCoA62/SKIP functions at a distal step in the transactivation process. Recent studies indicate that NCoA62/SKIP is a component of the spliceosome machinery and interacts with important splicing factors such as prp8 and the U5 200kDa helicase. Functional studies also support an involvement of NCoA62/SKIP in mRNA splicing. Collectively, these data suggest a pivotal role for NCoA62/SKIP in coupling transcriptional regulation by VDR to RNA splicing. They further solidify an important role for VDR/NR-interactors downstream of the transcription process in determining the overall response of Vitamin D and steroid hormone regulated genes.
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Affiliation(s)
- Paul N MacDonald
- Department of Pharmacology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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15
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Tewari M, Hu PJ, Ahn JS, Ayivi-Guedehoussou N, Vidalain PO, Li S, Milstein S, Armstrong CM, Boxem M, Butler MD, Busiguina S, Rual JF, Ibarrola N, Chaklos ST, Bertin N, Vaglio P, Edgley ML, King KV, Albert PS, Vandenhaute J, Pandey A, Riddle DL, Ruvkun G, Vidal M. Systematic interactome mapping and genetic perturbation analysis of a C. elegans TGF-beta signaling network. Mol Cell 2004; 13:469-82. [PMID: 14992718 DOI: 10.1016/s1097-2765(04)00033-4] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2003] [Revised: 12/16/2003] [Accepted: 12/23/2003] [Indexed: 11/24/2022]
Abstract
To initiate a system-level analysis of C. elegans DAF-7/TGF-beta signaling, we combined interactome mapping with single and double genetic perturbations. Yeast two-hybrid (Y2H) screens starting with known DAF-7/TGF-beta pathway components defined a network of 71 interactions among 59 proteins. Coaffinity purification (co-AP) assays in mammalian cells confirmed the overall quality of this network. Systematic perturbations of the network using RNAi, both in wild-type and daf-7/TGF-beta pathway mutant animals, identified nine DAF-7/TGF-beta signaling modifiers, seven of which are conserved in humans. We show that one of these has functional homology to human SNO/SKI oncoproteins and that mutations at the corresponding genetic locus daf-5 confer defects in DAF-7/TGF-beta signaling. Our results reveal substantial molecular complexity in DAF-7/TGF-beta signal transduction. Integrating interactome maps with systematic genetic perturbations may be useful for developing a systems biology approach to this and other signaling modules.
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Affiliation(s)
- Muneesh Tewari
- Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
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16
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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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17
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Medrano EE. Repression of TGF-beta signaling by the oncogenic protein SKI in human melanomas: consequences for proliferation, survival, and metastasis. Oncogene 2003; 22:3123-9. [PMID: 12793438 DOI: 10.1038/sj.onc.1206452] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Transforming growth factor-beta (TGF-beta ) has dual and paradoxical functions as a tumor suppressor and promoter of tumor progression and metastasis. TGF-Ji-mediated growth inhibition is gradually lost during melanoma tumor progression, but there are no measurable defects at the receptor level. Furthermore, melanoma cells release high levels of TGF-beta to the microenvironment, which upon activation induces matrix deposition, angiogenesis, survival, and transition to more aggressive phenotypes. The SKI and SnoN protein family associate with and repress the activity of Smad2, Smad3, and Smad4, three members of the TGF-fl signaling pathway. SKI also facilitates cell-cycle progression by targeting the RB pathway by at least two ways: it directly associates with RB and represses its activity when expressed at high levels, and indirectly, it represses Smad-mediated induction of p21(Waf-1) This results in increased CDK2 activity, RB phosphorylation,and inactivation. Therefore, high levels of SKI result in lesions to the RB pathway in a manner similar to p16 (INK4a) loss. SKI mRNA and protein levels dramatically increase during human melanoma tumor progression. In addition,the SKI protein shifts from nuclear localization in intraepidermal melanoma cells to nuclear and cytoplasmic in invasive and metastatic melanomas. Here, I discuss the basis for repression of intracellular TGF-beta signaling by SKI, some additional activities of this protein, and propose that by disrupting multiple tumor suppressor pathways, SKI functions as a melanoma oncogene.
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Affiliation(s)
- Estela E Medrano
- Departments of Molecural and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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18
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Prathapam T, Kühne C, Banks L. Skip interacts with the retinoblastoma tumor suppressor and inhibits its transcriptional repression activity. Nucleic Acids Res 2002; 30:5261-8. [PMID: 12466551 PMCID: PMC137971 DOI: 10.1093/nar/gkf658] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Ski interacting protein (Skip) plays an important role in the transforming activity of both v-Ski and EBNA2 (Epstein-Barr virus encoded latency protein) and is involved in EBNA2 and NotchIC activation of CBF1-repressed promoters. We have previously shown that Skip acts as a transcriptional co-activator on a number of cellular and viral promoters. Here, we report that Skip also interacts with pRb and, in cooperation with Ski, can overcome pRb-induced transcriptional repression. We show a strong and direct interaction between pRb and Skip, and we map the site of interaction to amino acid residues 171-353 of the evolutionarily conserved SNW domain of Skip. Furthermore, the combination of Skip and Ski can successfully overcome the G1 arrest and flat cell phenotype induced by pRb. Taken together, these studies suggest that one potential function of the Skip-Ski complex is to overcome the growth-suppressive activities of pRb.
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Affiliation(s)
- Tulasiram Prathapam
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012, Trieste, Italy
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19
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Prathapam T, Kühne C, Banks L. The HPV-16 E7 oncoprotein binds Skip and suppresses its transcriptional activity. Oncogene 2001; 20:7677-85. [PMID: 11753645 DOI: 10.1038/sj.onc.1204960] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2001] [Revised: 09/05/2001] [Accepted: 09/13/2001] [Indexed: 11/09/2022]
Abstract
E7 is the major transforming protein of human papillomavirus (HPV), which is implicated in the development of cervical cancer. The transforming activity of E7 has been attributed in part to its interaction with the retinoblastoma (Rb) tumour suppressor; however, the Rb interaction alone is not sufficient for transformation by E7. In a screen for cellular targets of HPV E7, we identified the Ski interacting protein, Skip, as a new interacting partner of E7. We show that HPV-16 E7 associates with Skip via sequences in its carboxy terminal region, and the evolutionarily conserved proline rich sequences (PRS) of the SNW domain of Skip. E7 functionally targets Skip in vivo and inhibits its transcriptional activation activity. Two transformation defective mutants of E7 were identified that failed both to bind Skip and to inhibit its transcriptional activity. These results suggest that inhibition of Skip function may contribute to cell transformation by HPV-16 E7.
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Affiliation(s)
- T Prathapam
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012, Trieste, Italy
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20
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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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21
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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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22
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Sun Y, Liu X, Eaton EN, Lane WS, Lodish HF, Weinberg RA. Interaction of the Ski oncoprotein with Smad3 regulates TGF-beta signaling. Mol Cell 1999; 4:499-509. [PMID: 10549282 DOI: 10.1016/s1097-2765(00)80201-4] [Citation(s) in RCA: 216] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
TGF-beta treatment of cells induces a variety of physiologic responses, including growth inhibition, differentiation, and induction of apoptosis. TGF-beta induces phosphorylation and nuclear translocation of Smad3. We describe here the association of Smad3 with the nuclear protooncogene protein Ski in response to the activation of TGF-beta signaling. Association with Ski represses transcriptional activation by Smad3, and overexpression of Ski renders cells resistant to the growth-inhibitory effects of TGF-beta. The transcriptional repression as well as the growth resistance to TGF-beta by overexpression of Ski can be overcome by overexpression of Smad3. These results demonstrate that Ski is a novel component of the TGF-beta signaling pathway and shed light on the mechanism of action of the Ski oncoprotein.
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Affiliation(s)
- Y Sun
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Massachusetts 02142, USA
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23
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Dahl R, Kieslinger M, Beug H, Hayman MJ. Transformation of hematopoietic cells by the Ski oncoprotein involves repression of retinoic acid receptor signaling. Proc Natl Acad Sci U S A 1998; 95:11187-92. [PMID: 9736711 PMCID: PMC21617 DOI: 10.1073/pnas.95.19.11187] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Ski oncogene has dramatic effects on the differentiation of several different cell types. It induces the differentiation of quail embryo cells into myoblasts and arrests the differentiation of chicken hematopoietic cells. The mechanism that Ski uses to carry out these disparate biological activities is unknown. However, we were struck by the similarity of these effects to those of certain members of the nuclear hormone receptor family. Both Ski and the thyroid hormone receptor-derived oncogene v-ErbA can arrest the differentiation of avian erythroblasts, and v-Ski-transformed avian multipotent progenitor cells resemble murine hematopoietic cells that express a dominant-negative form of the retinoic acid receptor, RARalpha. In this paper, we have tested the hypothesis that v-Ski and its cellular homologue c-Ski exert their effects by interfering with nuclear hormone receptor-induced transcription. We demonstrate that Ski associates with the RAR complex and can repress transcription from a retinoic acid response element. The physiological significance of this finding is demonstrated by the ability of high concentrations of a RARalpha-specific ligand to abolish v-Ski-induced transformation of the multipotent progenitors. These results strongly suggest that the ability of Ski to alter cell differentiation is caused in part by the modulation of RAR signaling pathways.
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Affiliation(s)
- R Dahl
- Department of Molecular Genetics and Microbiology and Institute of Cell and Developmental Biology, State University of New York, Stony Brook, NY 11794-5222, USA
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24
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KANO K, TOJO H, YAMANOUCHI K, SOETA C, TANAKA S, ISHII S, TACHI C. Skeletal Muscles of Transgenic Mice Expressing Human snoN, a Homologue of c-ski. J Reprod Dev 1998. [DOI: 10.1262/jrd.44.253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Kiyoshi KANO
- Laboratory of Applied Genetics, Department of Animal Resource Science, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113, Japan
| | - Hideaki TOJO
- Laboratory of Applied Genetics, Department of Animal Resource Science, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113, Japan
| | - Keitaro YAMANOUCHI
- Laboratory of Applied Genetics, Department of Animal Resource Science, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113, Japan
| | - Chie SOETA
- Laboratory of Applied Genetics, Department of Animal Resource Science, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113, Japan
| | - Satoshi TANAKA
- Laboratory of Applied Genetics, Department of Animal Resource Science, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113, Japan
| | - Shunsuke ISHII
- Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN), 3-1 Koyadai, Tsukuba-shi, Ibaraki 305, Japan
| | - Chikashi TACHI
- Laboratory of Developmental and Reproductive Biotechnology, School of Veterinary Medicine and Life Science, Azabu University, 1-17-71 Fuchinobe, Sagamihara-shi, Kanagawa 229, Japan
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25
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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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26
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Zheng G, Blumenthal KM, Ji Y, Shardy DL, Cohen SB, Stavnezer E. High affinity dimerization by Ski involves parallel pairing of a novel bipartite alpha-helical domain. J Biol Chem 1997; 272:31855-64. [PMID: 9395532 DOI: 10.1074/jbc.272.50.31855] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
c-Ski protein possesses a C-terminal dimerization domain that was deleted during the generation of v-ski, and has been implicated in the increased potency of c-ski in cellular transformation compared with the viral gene. The domain is predicted to consist of an extended alpha-helical segment made up of two motifs: a tandem repeat (TR) consisting of five imperfect repeats of 25 residues each and a leucine zipper (LZ) consisting of six heptad repeats. We have examined the structure and dimerization of TR or LZ individually or the entire TR-LZ domain. Using a quenched chemical cross-linking method, we show that the TR dimerizes with moderate efficiency (Kd = 4 x 10(-6) M), whereas LZ dimerizes poorly (Kd > 2 x 10(-5) M). However, the entire TR-LZ domain dimerizes efficiently (Kd = 2 x 10(-8) M), showing a cooperative effect of the two motifs. CD analyses indicate that all three proteins contain predominantly alpha-helices. Limited proteolysis of the TR-LZ dimer indicates that the two helical motifs are linked by a small loop. Interchain disulfide bond formation indicates that both the LZ and TR helices are oriented in parallel. We propose a model for the dimer interface in the TR region consisting of discontinuous clusters of hydrophobic residues forming "leucine buttons."
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Affiliation(s)
- G Zheng
- Department of Biochemistry, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106-4935, USA
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27
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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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28
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Kelder B, Richmond C, Stavnezer E, List EO, Kopchick JJ. Production, characterization and functional activities of v-Ski in cultured cells. Gene 1997; 202:15-21. [PMID: 9427540 DOI: 10.1016/s0378-1119(97)00439-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The v-ski oncogene was introduced into mammalian cells in order to study its biochemical and biological properties. v-Ski, produced at relatively high levels by mouse L cells stably transfected with this DNA, was localized to the cell nucleus, was of correct apparent molecular mass, and was capable of complexing with DNA. Transient transfection of reporter plasmids into control or Ski producing mouse L cells revealed that Ski acts as a transcriptional activator of various transcriptional regulatory elements, including CMVie, RSV LTR and SV40. These results indicate that mouse L cells contain the nuclear cofactor(s) required for the ability of v-Ski to bind to DNA and also suggest that the v-Ski present within the cells is functional.
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Affiliation(s)
- B Kelder
- Edison Biotechnology Institute, Ohio University, Athens 45701, USA.
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29
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Tarapore P, Richmond C, Zheng G, Cohen SB, Kelder B, Kopchick J, Kruse U, Sippel AE, Colmenares C, Stavnezer E. DNA binding and transcriptional activation by the Ski oncoprotein mediated by interaction with NFI. Nucleic Acids Res 1997; 25:3895-903. [PMID: 9380514 PMCID: PMC146989 DOI: 10.1093/nar/25.19.3895] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The Ski oncoprotein has been found to bind non-specifically to DNA in association with unindentified nuclear factors. In addition, Ski has been shown to activate transcription of muscle-specific and viral promoters/enhancers. The present study was undertaken to identify Ski's DNA binding and transcriptional activation partners by identifying specific DNA binding sites. We used nuclear extracts from a v-Ski-transduced mouse L-cell line and selected Ski-bound sequences from a pool of degenerate oligonucleotides with anti-Ski monoclonal antibodies. Two sequences were identified by this technique. The first (TGGC/ANNNNNT/GCCAA) is the previously identified binding site of the nuclear factor I (NFI) family of transcription factors. The second (TCCCNNGGGA) is the binding site of Olf-1/EBF. By electophoretic mobility shift assays we find that Ski is a component of one or more NFI complexes but we fail to detect Ski in Olf-1/EBF complexes. We show that Ski binds NFI proteins and activates transcription of NFI reporters, but only in the presence of NFI. We also find that homodimerization of Ski is essential for co-activation with NFI. However, the C-terminal dimerization domain of c-Ski, which is missing in v-Ski, can be substituted by the leucine zipper domain of GCN4.
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Affiliation(s)
- P Tarapore
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
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30
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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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Proux V, Provot S, Felder-Schmittbuhl MP, Laugier D, Calothy G, Marx M. Characterization of a leucine zipper-containing protein identified by retroviral insertion in avian neuroretina cells. J Biol Chem 1996; 271:30790-7. [PMID: 8940059 DOI: 10.1074/jbc.271.48.30790] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We reported previously that post-mitotic chicken embryonic neuroretina (NR) cells are induced to proliferate following in vitro infection with RAV-1, a retrovirus that does not carry an oncogene. NR cell multiplication results from the frequent activation and subsequent retroviral transduction of two related serine/threonine protein kinases, the c-mil/c-raf or c-Rmil/B-raf genes. We also showed that a very early event in the activation of these proto-oncogenes is the synthesis of chimeric mRNAs containing viral and cellular sequences joined by a splicing mechanism. In the current study, we have examined the ability of RAV-1 to induce proliferation of quail NR cells. By using the reverse transcription-polymerase chain reaction technique, we identified, in several proliferating quail NR cultures infected with RAV-1, a chimeric mRNA containing cellular sequences joined to the RAV-1 splice donor site. These cellular sequences are derived from a gene designated R10, which is expressed through a 1.9-kilobase (kb) mRNA detected in several embryonic tissues. A second transcript of 2.3 kb is specifically expressed in the NR, where both transcripts are developmentally regulated. The R10 cDNA encodes a 251-amino acid polypeptide that contains a leucine zipper motif. It exhibits significant similarity with the putative D52/N8L protein, encoded by an mRNA reported previously to be overexpressed in human breast and lung carcinomas. By using polyclonal antibodies specific for its amino-terminal and leucine zipper-containing regions, we identified the R10 gene product as a cytoplasmic protein of 23 kDa in cultured avian fibroblasts. A second protein of 30 kDa is detected in post-mitotic NR cells that express the 2.3-kb transcript. We also show, by in vitro transcription/translation and immunoprecipitation, that the R10 protein can readily form homodimers, presumably through its leucine zipper motif.
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Affiliation(s)
- V Proux
- Unité Mixte de Recherche 146 du CNRS, Institut Curie, Laboratoire 110, Centre Universitaire, 91405 Orsay Cédex, France.
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Tuck MT, James CB, Kelder B, Kopchick JJ. Elevation of internal 6-methyladenine mRNA methyltransferase activity after cellular transformation. Cancer Lett 1996; 103:107-13. [PMID: 8616802 DOI: 10.1016/0304-3835(96)04203-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A comparison of internal 6-methyladenine mRNA methyltransferase activity in a variety of cell types demonstrated an 8-15-fold increase as a result of cellular transformation. Utilizing adenovirus transformed rat embryo cells, it was found that the increase in methyltransferase activity was concomitant with or occurred rapidly after transformation. An 80-fold increase in activity was observed in the cells isolated from the transformed foci and remained elevated through subsequent passages. The relationship between methyltransferase activity and tumor formation was also investigated. High level expression of the avian ski oncogene in mouse L cells causes a reversion of the transformed phenotype to a non-transformed state, and resulted in a 47% reduction in the specific activity of the methyltransferase as compared with mock transfected cells.
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Affiliation(s)
- M T Tuck
- Department of Chemistry, Clippinger Laboratories, Ohio University, Athens 45701, USA
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Rulong S, Zhou R, Tsarfaty I, Hughes S, Vande Woude G, Pinto da Silva P. Immunogold labeling of oncogenic and tumor related proteins. Microsc Res Tech 1995; 31:159-73. [PMID: 7655089 DOI: 10.1002/jemt.1070310207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Immunogold labeling electron microscopy technique has been used to study the ultrastructural localization of oncogenic proteins: Mos, Met, Ski, and the tumor-associated protein, Muc1, as well as their relationship with other tumor-related proteins. By pre- and postembedding immunogold labeling electron microscopy techniques, we showed that the Mos protein pp39mos colocalized with microtubule bundles, suggesting that microtubulin or microtubule-associated protein(s) may be the substrate of Mos. Met protein was labeled at the microvilli of the lumen that are formed in cultured T47D cells, implying its potential involvement in lumen formation. Ski localization experiments revealed a unique globular structure "Ski body" that is present inside the nucleus of interphase chicken embryo fibroblast infected with Ski cDNA FB29 and FB2-29. Ski bodies were also found scattered in the cytoplasm of metaphase FB29 and FB2-29 Ski expressing chicken embryo fibroblasts. In T47D cells, tumor-associated protein Muc1 was associated with both the plasma membrane and the membranes of secretory vesicles in the cytoplasm. In MUC1 infected NIH3T3 cells, however, labeling showed that in addition to the plasma membrane and the membranes of secretory vesicles, some Muc1 gold spheres were seen inside the secretory vesicles, suggesting that the subcellular localization of the protein may vary in different cell types.
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Affiliation(s)
- S Rulong
- ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Maryland 21702-1201, USA
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Abstract
We have cloned and analyzed the chicken c-sno (cellular ski novel) gene. The promoter region and all of the intron/exon boundaries have been sequenced. The gene is approx. 12-kb long and contains six exons, the first of which is noncoding. The amino-acid sequences encoded in this first coding exon of c-sno and c-ski are highly related; however, the remainder of these two genes appears to be unrelated. Although there is evidence that the transcripts of mammalian c-sno are alternatively spliced, there is no evidence that chicken c-sno is alternatively spliced. The promoter region has a high G + C content and contains neither a TATAA nor a CAAT box. Potential binding sites for the transcription factors SP1, AP1 and AP2, are present upstream from the transcription start point.
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Affiliation(s)
- I Givol
- ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, MD 21702-1201, USA
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Ludolph DC, Neff AW, Parker MA, Mescher AL, Smith RC, Malacinski GM. Cloning and expression of the axolotl proto-oncogene ski. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1260:102-4. [PMID: 7999783 DOI: 10.1016/0167-4781(94)00194-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In vitro and in vivo overexpression studies have demonstrated that the c-ski proto-oncogene can influence proliferation, morphological transformation and myogenic differentiation. We report the isolation and expression of an axolotl (Ambystoma mexicanum) c-ski (aski) gene. Sequence analysis revealed a high degree of nucleotide and predicted amino acid (AA) homology with mammalian and anuran c-ski, showing the highest conservation to Xenopus laevis c-ski (74% nucleotide and 87% AA). Northern analysis showed that axolotl c-ski is expressed in unfertilized eggs and at increasing levels in embryos from blastula to tadpole stage. c-ski expression was also detected in larval limb muscle and in several stages of regenerating limb blastemas. These data indicate that axolotl c-ski is highly conserved among amphibians and mammals and suggests that it plays a role in urodele embryogenesis and limb regeneration.
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Affiliation(s)
- D C Ludolph
- Department of Biology, Indiana University, Bloomington 47405
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36
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Pearson-White S. SnoI, a novel alternatively spliced isoform of the ski protooncogene homolog, sno. Nucleic Acids Res 1993; 21:4632-8. [PMID: 8233802 PMCID: PMC311202 DOI: 10.1093/nar/21.19.4632] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We have cloned and sequenced a novel human isoform of sno, snoI for insertion. SnoI contains 1330 nucleotides inserted in place of 7 nucleotides of the snoN mRNA. Sno is a member of the ski protooncogene family, which has been implicated in muscle development. The two previously known sno alternatively spliced isoforms are snoN (684 amino acids), and snoA (415 amino acids); snoI encodes a truncated isoform of 399 amino acids (44,298 MW). Southern blot experiments show that snoI contains a third alternative exon from the sno gene; a single sno gene can express all three isoforms of sno by alternative splicing. All three isoforms contain the region that is most similar to the ski proto-oncogene. The relationship between snoI and snoN is analogous to that between delta fosB and fosB, where a truncated form of the fosB transcription factor is produced by alternative splicing. We find conservation of human snoI-specific sequences in several mammalian species, in monkey, dog, cow, rabbit and pig, but not in rodents, whereas the common portion of the sno gene is conserved in all vertebrate species tested. SnoN, snoA, and ski mRNAs accumulate in many human tissues including skeletal muscle; the snoI alternative mRNA accumulates more specifically in skeletal muscle. SnoI is also expressed in rhabdomyosarcoma tumor, a tumor that contains differentiated skeletal muscle. The tissue-specific alternative splicing of human snoI, an mRNA in the ski/sno gene family, and the presence of sno mRNAs in muscle are consistent with a proposed role for the sno oncogene in muscle gene regulation.
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Affiliation(s)
- S Pearson-White
- Department of Pediatrics, University of Virginia Medical Center, Charlottesville 22908
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37
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Grimes HL, Szente BE, Goodenow MM. C-ski cDNAs are encoded by eight exons, six of which are closely linked within the chicken genome. Nucleic Acids Res 1992; 20:1511-6. [PMID: 1579443 PMCID: PMC312231 DOI: 10.1093/nar/20.7.1511] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The c-ski locus extends a minimum of 65 kb in the chicken genome and is expressed as multiple mRNAs resulting from alternative exon usage. Four exons comprising approximately 1.5 kb of cDNA sequence have been mapped within the chicken c-ski locus. However, c-ski cDNAs include almost 3 kb of sequence for which the exon structure was not defined. From our studies using the polymerase chain reaction and templates of RNA and genomic DNA, it is clear that c-ski cDNAs are encoded by a minimum of eight exons. A long 3' untranslated region is contiguous in the genome with the distal portion of the ski open reading frame such that exon 8 is composed of both coding and noncoding sequences. Exons 2 and 3 are separated by more than 25 kb of genomic sequence. In contrast, exons 3 through 8, representing more than half the length of c-ski cDNA sequences, are closely linked within 10 kb in the chicken genome.
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Affiliation(s)
- H L Grimes
- Graduate Program in Immunology and Molecular Pathology, J.Hillis Miller Health Center, University of Florida, Gainesville 32610
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39
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Abstract
The v-ski oncogene is a truncated version of the cellular proto-oncogene, c-ski, and lacks sequences coding for both the N- and C-terminal ends of the c-ski protein. In the region of overlap, v-ski and c-ski differ by only one amino acid. To determine whether these differences underlie v-ski's oncogenic activation, we have cloned cDNAs for several alternatively spliced c-ski mRNAs and introduced these cDNAs into replication-competent retroviral vectors. The biological activities of these c-ski constructs have been compared with those of v-ski. We found that all c-ski gene products, when expressed at high levels from the promoter in the retroviral long terminal repeat, can induce morphological transformation, anchorage independence, and muscle differentiation in avian cells. Cells that are susceptible to ski-induced transformation and myogenesis normally express endogenous c-ski at low levels. Thus, it appears that overexpression of ski is sufficient for oncogenic and myogenic activation.
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Affiliation(s)
- C Colmenares
- Department of Molecular Genetics, University of Cincinnati Medical Center, Ohio 45267-0524
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40
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Sutrave P, Kelly AM, Hughes SH. ski can cause selective growth of skeletal muscle in transgenic mice. Genes Dev 1990; 4:1462-72. [PMID: 2253874 DOI: 10.1101/gad.4.9.1462] [Citation(s) in RCA: 142] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have created several lines of mice that contain a truncated chicken c-ski cDNA linked to an MSV LTR promoter. Adult mice from three independent lines show large increases in skeletal muscle. All three lines of mice express high levels of c-ski mRNA and protein in skeletal muscle. All other tissues examined show little or no expression of the c-ski transgene. The muscles of one of the three lines were examined in more detail. Type II fast fibers undergo selective hypertrophy in affected muscles of this line.
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Affiliation(s)
- P Sutrave
- National Cancer Institute-Frederick Cancer Research and Development Center, ABL-Basic Research Program, Maryland 21701-1013
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41
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Abstract
We constructed replication-competent avian retrovirus vectors that contain two of the three known types of chicken c-ski cDNAs and a third vector that contains a truncated c-ski cDNA. We developed antisera that recognize the c-ski proteins made by the three transforming c-ski viruses. All three proteins (apparent molecular masses, 50, 60, and 90 kilodaltons) are localized primarily in the nucleus. The proteins are differentially phosphorylated; immunofluorescence also suggests that there are differences in subnuclear localization of the c-ski proteins and that c-ski protein is associated with condensed chromatin in dividing cells.
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42
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Sutrave P, Copeland TD, Showalter SD, Hughes SH. Characterization of chicken c-ski oncogene products expressed by retrovirus vectors. Mol Cell Biol 1990; 10:3137-44. [PMID: 2188109 PMCID: PMC360678 DOI: 10.1128/mcb.10.6.3137-3144.1990] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We constructed replication-competent avian retrovirus vectors that contain two of the three known types of chicken c-ski cDNAs and a third vector that contains a truncated c-ski cDNA. We developed antisera that recognize the c-ski proteins made by the three transforming c-ski viruses. All three proteins (apparent molecular masses, 50, 60, and 90 kilodaltons) are localized primarily in the nucleus. The proteins are differentially phosphorylated; immunofluorescence also suggests that there are differences in subnuclear localization of the c-ski proteins and that c-ski protein is associated with condensed chromatin in dividing cells.
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Affiliation(s)
- P Sutrave
- Advanced BioScience Laboratories, Inc., National Cancer Institute--Frederick Cancer Research and Development Center, Maryland 21701
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43
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Nagase T, Mizuguchi G, Nomura N, Ishizaki R, Ueno Y, Ishii S. Requirement of protein co-factor for the DNA-binding function of the human ski proto-oncogene product. Nucleic Acids Res 1990; 18:337-43. [PMID: 2183181 PMCID: PMC330272 DOI: 10.1093/nar/18.2.337] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We identified the human c-ski gene product (c-Ski) as a protein with the apparent molecular weight of 100,000, p100c-ski, by using a c-Ski-specific polyclonal antibody. p100c-ski was a nuclear protein and p100c-ski in nuclear extracts of Molt4 cells bound to calf thymus DNA cellulose, but the bacterially synthesized c-Ski did not, suggesting that Ski was associated with another protein(s) and that the Ski complex had DNA-binding activity. This hypothesis was supported by the finding that the bacterially synthesized Ski bounds to DNA cellulose after being mixed with a nuclear extract of Molt4 cells. By use of a series of deletion mutants of Ski synthesized in an in vitro translation system, two portions in Ski were found to be necessary for the DNA binding of the Ski complex: the N-proximal portion containing a cystein/histidine-rich domain and the C-terminal portion including a region rich in basic amino acids.
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Affiliation(s)
- T Nagase
- Tsukuba life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan
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44
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Abstract
Three types of c-ski cDNAs have been isolated from two different chicken cDNA libraries. Sequence comparisons suggest that the cDNAs derive from alternatively spliced mRNAs. A short stretch of sequence homology that exists between c-ski and avian leukosis virus may have played a role in viral transduction.
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45
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The v-ski oncogene encodes a truncated set of c-ski coding exons with limited sequence and structural relatedness to v-myc. Mol Cell Biol 1989. [PMID: 2674685 DOI: 10.1128/mcb.9.9.4038] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nucleotide sequence of a biologically active v-ski gene from a cloned proviral segment shows that ski is a 1,312-base sequence embedded in the p19 region of the avian leukosis virus gag gene. The v-ski sequence contains a single open translational reading frame that encodes a polypeptide with a molecular mass of 49,000 daltons. The predicted amino acid sequence includes nuclear localization motifs that have been identified in other nuclear oncoproteins. It also contains a proline-rich region and a set of cysteine and histidine residues that could constitute a metal-binding domain. Two regions of the amino acid sequences of v-ski and v-myc are related, and the two proteins exhibit similar distributions of hydrophobic and hydrophilic amino acids. Cloned segments of the chicken c-ski proto-oncogene totaling 65 kilobases have been analyzed, and regions related to v-ski have been sequenced. The results indicate that v-ski is derived from at least five coding exons of c-ski, that it is correctly spliced, and that it is missing c-ski coding sequences at both its 5' and 3' ends. The c-ski and avian leukosis virus sequences that overlap the 5' virus/v-ski junction in Sloan-Kettering virus contain an 18-of-20-base sequence match that presumably played a role in the transduction of ski by facilitating virus/c-ski recombination.
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Abstract
Quail embryo cells (QECs) are primary cultures of fibroblastoid cells that become myogenic after infection with avian retroviruses expressing the ski oncogene (SKVs). ski also stimulates proliferation of QECs and induces morphological transformation and anchorage-independent growth. Paradoxically, ski-transformed clones picked from soft agar are capable of muscle differentiation. ski-induced differentiation is essentially indistinguishable from that of uninfected myoblasts in culture with regard to muscle-specific gene expression, commitment, and inhibition by growth factors or other oncogenes. However, ski-induced myoblasts have less stringent requirements for growth and differentiation. Uninfected QECs cannot differentiate and do not express an early marker for the myogenic lineage. Clonal analysis indicates that at least 40% of QECs are converted by ski to differentiating myoblasts. The data suggest that ski induces either the capacity for differentiation in an "incompetent" muscle precursor or the determination of nonmyogenic cells to the myogenic lineage.
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Affiliation(s)
- C Colmenares
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati Medical Center, Ohio 45267-0524
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47
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Sutrave P, Hughes SH. Isolation and characterization of three distinct cDNAs for the chicken c-ski gene. Mol Cell Biol 1989; 9:4046-51. [PMID: 2779576 PMCID: PMC362469 DOI: 10.1128/mcb.9.9.4046-4051.1989] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Three types of c-ski cDNAs have been isolated from two different chicken cDNA libraries. Sequence comparisons suggest that the cDNAs derive from alternatively spliced mRNAs. A short stretch of sequence homology that exists between c-ski and avian leukosis virus may have played a role in viral transduction.
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Affiliation(s)
- P Sutrave
- National Cancer Institute-Frederick Cancer Research Facility, BRI-Basic Research Program, Maryland 21701
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48
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Stavnezer E, Brodeur D, Brennan LA. The v-ski oncogene encodes a truncated set of c-ski coding exons with limited sequence and structural relatedness to v-myc. Mol Cell Biol 1989; 9:4038-45. [PMID: 2674685 PMCID: PMC362468 DOI: 10.1128/mcb.9.9.4038-4045.1989] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The nucleotide sequence of a biologically active v-ski gene from a cloned proviral segment shows that ski is a 1,312-base sequence embedded in the p19 region of the avian leukosis virus gag gene. The v-ski sequence contains a single open translational reading frame that encodes a polypeptide with a molecular mass of 49,000 daltons. The predicted amino acid sequence includes nuclear localization motifs that have been identified in other nuclear oncoproteins. It also contains a proline-rich region and a set of cysteine and histidine residues that could constitute a metal-binding domain. Two regions of the amino acid sequences of v-ski and v-myc are related, and the two proteins exhibit similar distributions of hydrophobic and hydrophilic amino acids. Cloned segments of the chicken c-ski proto-oncogene totaling 65 kilobases have been analyzed, and regions related to v-ski have been sequenced. The results indicate that v-ski is derived from at least five coding exons of c-ski, that it is correctly spliced, and that it is missing c-ski coding sequences at both its 5' and 3' ends. The c-ski and avian leukosis virus sequences that overlap the 5' virus/v-ski junction in Sloan-Kettering virus contain an 18-of-20-base sequence match that presumably played a role in the transduction of ski by facilitating virus/c-ski recombination.
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Affiliation(s)
- E Stavnezer
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Ohio 45267-0524
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49
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Nomura N, Sasamoto S, Ishii S, Date T, Matsui M, Ishizaki R. Isolation of human cDNA clones of ski and the ski-related gene, sno. Nucleic Acids Res 1989; 17:5489-500. [PMID: 2762147 PMCID: PMC318172 DOI: 10.1093/nar/17.14.5489] [Citation(s) in RCA: 148] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
cDNA clones of ski and the ski-related gene, sno, were obtained by screening human cDNA libraries. The predicted open reading frame of h-ski could encode a protein of 728 amino acid residues. The h-ski protein is highly homologous with the v-ski protein. The overall homology between h-ski and v-ski is 91% at the amino acid level. DNA sequencing analysis revealed two types of cDNA clones from the sno (ski-related novel gene) gene, possibly due to alternative splicing. The first type, named snoN (non Alu-containing), encoded a protein of 684 amino acid residues. The second type, named snoA (Alu-containing), encoded a protein of 415 amino acid residues. The first 366 amino acid residues of snoN and snoA are the same, but subsequent amino acids show divergence. Several transcripts of h-ski (6.0, 4.7, 3.8, 3.0, 2.1 and 1.8 kb) were detected. The mRNAs of h-sno were 6.2, 4.4 and 3.2kb.
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Affiliation(s)
- N Nomura
- Molecular Oncology Laboratory, Nippon Veterinary and Zootechnical College, Tokyo, Japan
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50
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Marx M, Crisanti P, Eychène A, Béchade C, Laugier D, Ghysdaël J, Pessac B, Calothy G. Activation and transduction of c-mil sequences in chicken neuroretina cells induced to proliferate by infection with avian lymphomatosis virus. J Virol 1988; 62:4627-33. [PMID: 2846875 PMCID: PMC253575 DOI: 10.1128/jvi.62.12.4627-4633.1988] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We report that nondividing neuroretina cells from chicken embryos can be induced to proliferate following infection with Rous-associated virus type 1 (RAV-1), an avian lymphomatosis retrovirus lacking transforming genes. Multiplication of RAV-1-infected neuroretina cells is observed after a long latency period and takes place initially in a small number of cells. We also show that serial virus passaging onto fresh neuroretina cultures leads to the generation of novel mitogenic viruses containing the mil oncogene. DNA analysis indicated that RAV-1 is the only provirus detected in cells infected at virus passage 1, whereas neuroretina cells infected at subsequent virus passages harbor mil-containing proviruses. Three viruses, designated IC1, IC2, and IC3, were molecularly cloned. Restriction mapping indicated that in each virus, truncated c-mil sequences were inserted within different portions of the RAV-1 genome. In addition, IC1 and IC2 viruses have transduced novel sequences that belong to the 3' noncoding portion of the c-mil locus. All three viruses induce neuroretina cell multiplication and direct the synthesis of mil-specific proteins. Proliferation of neuroretina cells infected at passage 1 of RAV-1 was not associated with any detectable rearrangement of c-mil, when a v-mil probe was used. However, these cells expressed high levels of an aberrant 2.8-kilobase mRNA hybridizing to mil but not to a long terminal repeat probe. Therefore, transcriptional activation of a portion of c-mil could represent the initial events induced by RAV-1 infection and lead to retroviral transduction of activated c-mil sequences.
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Affiliation(s)
- M Marx
- Institut Curie-Biologie, Centre Universitaire, Orsay, France
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