1
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Gautam S, Fioravanti J, Zhu W, Le Gall JB, Brohawn P, Lacey NE, Hu J, Hocker JD, Hawk NV, Kapoor V, Telford WG, Gurusamy D, Yu Z, Bhandoola A, Xue HH, Roychoudhuri R, Higgs BW, Restifo NP, Bender TP, Ji Y, Gattinoni L. The transcription factor c-Myb regulates CD8 + T cell stemness and antitumor immunity. Nat Immunol 2019; 20:337-349. [PMID: 30778251 PMCID: PMC6489499 DOI: 10.1038/s41590-018-0311-z] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 12/19/2018] [Indexed: 12/13/2022]
Abstract
Stem cells are maintained by transcriptional programs that promote self-renewal and repress differentiation. Here, we found that the transcription factor c-Myb was essential for generating and maintaining stem cells in the CD8+ T cell memory compartment. Following viral infection, CD8+ T cells lacking Myb underwent terminal differentiation and generated fewer stem cell-like central memory cells than did Myb-sufficient T cells. c-Myb acted both as a transcriptional activator of Tcf7 (which encodes the transcription factor Tcf1) to enhance memory development and as a repressor of Zeb2 (which encodes the transcription factor Zeb2) to hinder effector differentiation. Domain-mutagenesis experiments revealed that the transactivation domain of c-Myb was necessary for restraining differentiation, whereas its negative regulatory domain was critical for cell survival. Myb overexpression enhanced CD8+ T cell memory formation, polyfunctionality and recall responses that promoted curative antitumor immunity after adoptive transfer. These findings identify c-Myb as a pivotal regulator of CD8+ T cell stemness and highlight its therapeutic potential.
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Affiliation(s)
- Sanjivan Gautam
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Jessica Fioravanti
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Wei Zhu
- Department of Bioinformatics, Inova Translational Medicine Institute, Fairfax, VA, USA
| | - John B Le Gall
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | | | - Neal E Lacey
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Jinhui Hu
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - James D Hocker
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Nga Voong Hawk
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Veena Kapoor
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - William G Telford
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Devikala Gurusamy
- Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Zhiya Yu
- Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Avinash Bhandoola
- Laboratory of Genome Integrity, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Hai-Hui Xue
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Rahul Roychoudhuri
- Laboratory of Lymphocyte Signaling and Development, Babraham Institute, Cambridge, UK
| | | | - Nicholas P Restifo
- Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Timothy P Bender
- Department of Microbiology, University of Virginia, Charlottesville, VA, USA
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, VA, USA
| | - Yun Ji
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
- Cellular Biomedicine Group, Gaithersburg, MD, USA
| | - Luca Gattinoni
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA.
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2
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A novel HER2 gene body enhancer contributes to HER2 expression. Oncogene 2017; 37:687-694. [PMID: 29035388 PMCID: PMC5794618 DOI: 10.1038/onc.2017.382] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 08/09/2017] [Accepted: 09/08/2017] [Indexed: 12/13/2022]
Abstract
The transcriptional regulation of the human epidermal growth factor receptor-2 (HER2) contributes to an enhanced HER2 expression in HER2-positive breast cancers with HER2 gene amplification and HER2-low or HER2-negative breast cancers following radiotherapy or endocrine therapy, and this drives tumorigenesis and the resistance to therapy. Epigenetic mechanisms are critical for transcription regulation, however, such mechanisms in the transcription regulation of HER2 are limited to the involvement of tri-methylated histone 3 lysine 4 (H3K4me3) and acetylated histone 3 lysine 9 (H3K9ac) at the HER2 promoter region. Here, we report the identification of a novel enhancer in the HER2 3’ gene body, which we have termed HER2 gene body enhancer (HGE). The HGE starts from the 3’ end of intron 19 and extends into intron 22, possesses enhancer histone modification marks in specific cells and enhances the transcriptional activity of the HER2 promoters. We also found that TFAP2C, a known regulator of HER2, binds to HGE and is required for its enhancer function and that DNA methylation in the HGE region inhibits the histone modifications characterizing enhancer and is inversely correlated with HER2 expression in breast cancer samples. The identification of this novel enhancer sheds a light on the roles of epigenetic mechanisms in HER2 transcription, in both HER2-positive breast cancer samples and individuals with HER2-low or HER2-negative breast cancers undergoing radiotherapy or endocrine therapy.
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3
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Duval C, Zaniolo K, Leclerc S, Salesse C, Guérin SL. Characterization of the human α9 integrin subunit gene: Promoter analysis and transcriptional regulation in ocular cells. Exp Eye Res 2015; 135:146-63. [PMID: 25746835 DOI: 10.1016/j.exer.2015.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 01/26/2015] [Accepted: 03/02/2015] [Indexed: 11/29/2022]
Abstract
α9β1 is the most recent addition to the integrin family of membrane receptors and consequently remains the one that is the least characterized. To better understand how transcription of the human gene encoding the α9 subunit is regulated, we cloned the α9 promoter and characterized the regulatory elements that are required to ensure its transcription. Transfection of α9 promoter/CAT plasmids in primary cultured human corneal epithelial cells (HCECs) and uveal melanoma cell lines demonstrated the presence of both negative and positive regulatory elements along the α9 promoter and positioned the basal α9 promoter to within 118 bp from the α9 mRNA start site. In vitro DNaseI footprinting and in vivo ChIP analyses demonstrated the binding of the transcription factors Sp1, c-Myb and NFI to the most upstream α9 negative regulatory element. The transcription factors Sp1 and NFI were found to bind the basal α9 promoter individually but Sp1 binding clearly predominates when both transcription factors are present in the same extract. Suppression of Sp1 expression through RNAi also caused a dramatic reduction in the expression of the α9 gene. Most of all, addition of tenascin-C (TNC), the ligand of α9β1, to the tissue culture plates prior to seeding HCECs increased α9 transcription whereas it simultaneously decreased expression of the α5 integrin subunit gene. This dual regulatory action of TNC on the transcription of the α9 and α5 genes suggests that both these integrins must work together to appropriately regulate cell adhesion, migration and differentiation that are hallmarks of tissue wound healing.
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Affiliation(s)
- Céline Duval
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada
| | - Karine Zaniolo
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada
| | - Steeve Leclerc
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada
| | - Christian Salesse
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada; Département d'Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Sylvain L Guérin
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada; Département d'Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC, Canada.
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4
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Complete genome sequence of a J subgroup avian leukosis virus isolated from local commercial broilers. J Virol 2013; 86:11937-8. [PMID: 23043170 DOI: 10.1128/jvi.02009-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Subgroup J avian leukosis virus (ALV-J) isolate GDKP1202 was isolated from a 50-day-old local yellow commercial broiler in the Guangdong province of China in 2012. Here we report the complete genomic sequence of the GDKP1202 isolate, which caused high mortality, serious growth suppression, thymic atrophy, and liver enlargement in commercial broilers. A novel potential binding site (5'-GGCACCTCC-3') for c-myb was identified in the GDKP1202 genome. These findings will provide additional insights into the molecular characteristics in the genomes and pathogenicity of ALV-J.
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5
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Lungova V, Buchtova M, Janeckova E, Tucker AS, Knopfova L, Smarda J, Matalova E. Localization of c-MYB in differentiated cells during postnatal molar and alveolar bone development. Eur J Oral Sci 2012; 120:495-504. [DOI: 10.1111/j.1600-0722.2012.01004.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2012] [Indexed: 12/12/2022]
Affiliation(s)
| | | | | | - Abigail S. Tucker
- Department of Craniofacial Development and Stem Cell Biology, and Department of Orthodontics; KCL; London; UK
| | - Lucia Knopfova
- Department of Experimental Biology; Faculty of Science; Masaryk University; Brno; Czech Republic
| | - Jan Smarda
- Department of Experimental Biology; Faculty of Science; Masaryk University; Brno; Czech Republic
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Kurima K, Hertzano R, Gavrilova O, Monahan K, Shpargel KB, Nadaraja G, Kawashima Y, Lee KY, Ito T, Higashi Y, Eisenman DJ, Strome SE, Griffith AJ. A noncoding point mutation of Zeb1 causes multiple developmental malformations and obesity in Twirler mice. PLoS Genet 2011; 7:e1002307. [PMID: 21980308 PMCID: PMC3183090 DOI: 10.1371/journal.pgen.1002307] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 07/30/2011] [Indexed: 01/05/2023] Open
Abstract
Heterozygous Twirler (Tw) mice develop obesity and circling behavior associated with malformations of the inner ear, whereas homozygous Tw mice have cleft palate and die shortly after birth. Zeb1 is a zinc finger protein that contributes to mesenchymal cell fate by repression of genes whose expression defines epithelial cell identity. This developmental pathway is disrupted in inner ears of Tw/Tw mice. The purpose of our study was to comprehensively characterize the Twirler phenotype and to identify the causative mutation. The Tw/+ inner ear phenotype includes irregularities of the semicircular canals, abnormal utricular otoconia, a shortened cochlear duct, and hearing loss, whereas Tw/Tw ears are severely malformed with barely recognizable anatomy. Tw/+ mice have obesity associated with insulin-resistance and have lymphoid organ hypoplasia. We identified a noncoding nucleotide substitution, c.58+181G>A, in the first intron of the Tw allele of Zeb1 (Zeb1Tw). A knockin mouse model of c.58+181G>A recapitulated the Tw phenotype, whereas a wild-type knockin control did not, confirming the mutation as pathogenic. c.58+181G>A does not affect splicing but disrupts a predicted site for Myb protein binding, which we confirmed in vitro. In comparison, homozygosity for a targeted deletion of exon 1 of mouse Zeb1, Zeb1ΔEx1, is associated with a subtle abnormality of the lateral semicircular canal that is different than those in Tw mice. Expression analyses of E13.5 Twirler and Zeb1ΔEx1 ears confirm that Zeb1ΔEx1 is a null allele, whereas Zeb1Tw RNA is expressed at increased levels in comparison to wild-type Zeb1. We conclude that a noncoding point mutation of Zeb1 acts via a gain-of-function to disrupt regulation of Zeb1Tw expression, epithelial-mesenchymal cell fate or interactions, and structural development of the inner ear in Twirler mice. This is a novel mechanism underlying disorders of hearing or balance. Twirler (Tw) mice have a combination of abnormalities that includes cleft palate, malformations of the inner ear, hearing loss, vestibular dysfunction, obesity, and lymphoid hypoplasia. In this study, we show that the underlying mutation affects the Zeb1 gene. Zeb1 was already known to encode a protein normally expressed in mesenchymal cells, where it represses expression of genes that are uniquely expressed in epithelial cells. The Tw mutation is a rare example of a single-nucleotide substitution in a region of a gene that does not encode protein, promoter, or splice sites, so we engineered a mouse model with the mutation that confirmed its causative role. The Tw mutation disrupts a consensus DNA binding site sequence for the Myb family of regulatory proteins. We conclude that this mutation leads to abnormal expression of Zeb1, structural malformations of the inner ear, and a loss of hearing and balance function. A similar mechanism may underlie other features of Twirler, such as obesity and cleft palate.
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Affiliation(s)
- Kiyoto Kurima
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Ronna Hertzano
- Department of Otorhinolaryngology–Head and Neck Surgery, University of Maryland, Baltimore, Maryland, United States of America
| | - Oksana Gavrilova
- Mouse Metabolism Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kelly Monahan
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Karl B. Shpargel
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Garani Nadaraja
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Yoshiyuki Kawashima
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Kyu Yup Lee
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Taku Ito
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
| | - Yujiro Higashi
- Department of Perinatology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Japan
| | - David J. Eisenman
- Department of Otorhinolaryngology–Head and Neck Surgery, University of Maryland, Baltimore, Maryland, United States of America
| | - Scott E. Strome
- Department of Otorhinolaryngology–Head and Neck Surgery, University of Maryland, Baltimore, Maryland, United States of America
| | - Andrew J. Griffith
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail:
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7
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Miao RY, Drabsch Y, Cross RS, Cheasley D, Carpinteri S, Pereira L, Malaterre J, Gonda TJ, Anderson RL, Ramsay RG. MYB is essential for mammary tumorigenesis. Cancer Res 2011; 71:7029-37. [PMID: 21948968 DOI: 10.1158/0008-5472.can-11-1015] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
MYB oncogene upregulation is associated with estrogen receptor (ER)-positive breast cancer, but disease requirements for MYB function in vivo have not been explored. In this study, we provide evidence of a critical requirement for MYB functions in models of human and murine breast cancer. In human breast cancer, we found that MYB expression was critical for tumor cell growth both in vitro and in vivo in xenograft settings. In transgenic knockout mice, tissue-specific deletion of the murine MYB gene caused a transient defect in mammary gland development that was reflected in delayed ductal branching and defective apical bud formation. In mouse mammary tumor virus (MMTV)-NEU mice where tumors are initiated by activation of HER2, MYB deletion was sufficient to abolish tumor formation. In the more aggressive MMTV-PyMT model system, MYB deletion delayed tumorigenesis significantly. Together, the findings in these transgenic knockout models implied that MYB was critical during an early window in mammary development when it was essential for tumor initiation, even though MYB loss did not exert a lasting impact upon normal mammary function. Two important MYB-target genes that promote cell survival, BCL2 and GRP78/BIP, were each elevated compared with nontransformed mammary epithelial cells, thereby promoting survival as confirmed in colony formation assays in vitro. Taken together, our findings establish a role for MYB at the hub of ER- and HER2-dependent pathways in mammary carcinogenesis.
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Affiliation(s)
- Rebecca Yu Miao
- Peter MacCallum Cancer Centre and Department of Pathology, University of Melbourne, Melbourne, Victoria, Australia
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8
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Zhao L, Glazov EA, Pattabiraman DR, Al-Owaidi F, Zhang P, Brown MA, Leo PJ, Gonda TJ. Integrated genome-wide chromatin occupancy and expression analyses identify key myeloid pro-differentiation transcription factors repressed by Myb. Nucleic Acids Res 2011; 39:4664-79. [PMID: 21317192 PMCID: PMC3113568 DOI: 10.1093/nar/gkr024] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/11/2011] [Accepted: 01/12/2011] [Indexed: 12/28/2022] Open
Abstract
To gain insight into the mechanisms by which the Myb transcription factor controls normal hematopoiesis and particularly, how it contributes to leukemogenesis, we mapped the genome-wide occupancy of Myb by chromatin immunoprecipitation followed by massively parallel sequencing (ChIP-Seq) in ERMYB myeloid progenitor cells. By integrating the genome occupancy data with whole genome expression profiling data, we identified a Myb-regulated transcriptional program. Gene signatures for leukemia stem cells, normal hematopoietic stem/progenitor cells and myeloid development were overrepresented in 2368 Myb regulated genes. Of these, Myb bound directly near or within 793 genes. Myb directly activates some genes known critical in maintaining hematopoietic stem cells, such as Gfi1 and Cited2. Importantly, we also show that, despite being usually considered as a transactivator, Myb also functions to repress approximately half of its direct targets, including several key regulators of myeloid differentiation, such as Sfpi1 (also known as Pu.1), Runx1, Junb and Cebpb. Furthermore, our results demonstrate that interaction with p300, an established coactivator for Myb, is unexpectedly required for Myb-mediated transcriptional repression. We propose that the repression of the above mentioned key pro-differentiation factors may contribute essentially to Myb's ability to suppress differentiation and promote self-renewal, thus maintaining progenitor cells in an undifferentiated state and promoting leukemic transformation.
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Affiliation(s)
| | | | | | | | | | | | | | - Thomas J. Gonda
- The University of Queensland Diamantina Institute, Brisbane, Queensland 4102, Australia
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9
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Deblois G, Chahrour G, Perry MC, Sylvain-Drolet G, Muller WJ, Giguère V. Transcriptional control of the ERBB2 amplicon by ERRalpha and PGC-1beta promotes mammary gland tumorigenesis. Cancer Res 2010; 70:10277-87. [PMID: 20961995 DOI: 10.1158/0008-5472.can-10-2840] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Overexpression of ERBB2 and its neighboring genes on chromosome 17 occurs in approximately 25% of breast tumors and is associated with poor prognosis. While amplification of the 17q12-21 chromosomal region often correlates with an increase in the transcriptional rates of the locus, the molecular mechanisms and the factors involved in the coordinated expression of genes residing within the ERBB2 amplicon remain largely unknown. Here we demonstrate that estrogen-related receptor α (ERRα, NR3B1) and its coregulator PGC-1β are key effectors in this process. Using a mouse model of ERBB2-initiated mammary tumorigenesis, we first show that ablation of ERRα significantly delays ERBB2-induced tumor development and lowers the levels of amplicon transcripts. Chromosome 17q-wide binding site location analyses in human breast cancer cells show preferential recruitment of ERRα to DNA segments associated with the ERBB2 amplicon. Furthermore, ERRα directs the co-recruitment of the coactivator PGC-1β to segments in the 17q12 region and the recruitment of RNA polymerase II to the promoters of the ERBB2 and coamplified genes. ERRα and PGC-1β also participate in the de-repression of ERBB2 expression through competitive genomic cross-talk with estrogen receptor α (ERα) and, as a consequence, influence tamoxifen sensitivity in breast cancer cells. Taken together, our results suggest that ERRα and PGC-1β are key players in the etiology of malignant breast cancer by coordinating the transcriptional regulation of genes located in the 17q12 region, a process that also involves interference with the repressive function of ERα on ERBB2 expression.
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MESH Headings
- Animals
- Breast Neoplasms/genetics
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cell Line, Tumor
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Chromosomes, Human, Pair 17
- Drug Resistance, Neoplasm
- Female
- GRB7 Adaptor Protein/genetics
- Gene Amplification
- Gene Expression Regulation, Neoplastic
- Genes, erbB-2
- Humans
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/metabolism
- Mice
- Mice, Transgenic
- RNA-Binding Proteins
- Receptor, ErbB-2/biosynthesis
- Receptor, ErbB-2/genetics
- Receptors, Estrogen/genetics
- Receptors, Estrogen/metabolism
- Tamoxifen/pharmacology
- ERRalpha Estrogen-Related Receptor
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Affiliation(s)
- Geneviève Deblois
- Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
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10
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Shimizu H, Nakagawa Y, Murakami C, Aoki N, Kim-Mitsuyama S, Miyazaki H. Protein tyrosine phosphatase PTPepsilonM negatively regulates PDGF beta-receptor signaling induced by high glucose and PDGF in vascular smooth muscle cells. Am J Physiol Cell Physiol 2010; 299:C1144-52. [PMID: 20686073 DOI: 10.1152/ajpcell.00536.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular smooth muscle cell (VSMC) proliferation and migration and vascular endothelial cell (VEC) dysfunction are closely associated with the development of atherosclerosis. We previously demonstrated that protein tyrosine phosphatase ε M (PTPεM) promotes VEC survival and migration. The present study investigates the biological functions of PTPεM in VSMCs and determines whether PTPεM is implicated in diabetes-accelerated atherosclerosis. We overexpressed wild-type and inactive PTPεM and an small interfering RNA (siRNA) of PTPεM by using an adenovirus vector to investigate the effects of PTPεM upon platelet-derived growth factor (PDGF)- and high glucose (HG)-induced responses of rat VSMCs in vitro. We found that PTPεM decreased PDGF-induced DNA synthesis and migration by reducing the phosphorylation level of the PDGF β-receptor (PDGFRβ) with subsequently suppressed H(2)O(2) generation. The HG content in the medium generated H(2)O(2), upregulated PDGFRβ expression and its tyrosine-phosphorylation, and elevated NADPH oxidase 1 (Nox1) expression even without exogenous PDGF, all of which were downregulated by PTPεM. The PDGFR inhibitor AG1296 also blocked HG-induced Nox1 expression and H(2)O(2) production. Moreover, HG suppressed PTPεM expression itself, which was blocked by the antioxidant N-acetyl-l-cysteine. The effects of PTPεM siRNA were the opposite of those of wild-type PTPεM. Therefore, PTPεM negatively regulates PDGFRβ-mediated signaling pathways that are crucial for the pathogenesis of atherosclerosis, and PTPεM may be involved in diabetes-accelerated atherosclerosis.
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Affiliation(s)
- Hidehisa Shimizu
- Graduate School of Life and Environmental Sciences, Alliance for Research on North Africa, University of Tsukuba, Ibaraki, Japan
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11
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Nagaoka H, Tran TH, Kobayashi M, Aida M, Honjo T. Preventing AID, a physiological mutator, from deleterious activation: regulation of the genomic instability that is associated with antibody diversity. Int Immunol 2010; 22:227-35. [DOI: 10.1093/intimm/dxq023] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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12
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Tran TH, Nakata M, Suzuki K, Begum NA, Shinkura R, Fagarasan S, Honjo T, Nagaoka H. B cell-specific and stimulation-responsive enhancers derepress Aicda by overcoming the effects of silencers. Nat Immunol 2009; 11:148-54. [PMID: 19966806 DOI: 10.1038/ni.1829] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 10/28/2009] [Indexed: 01/17/2023]
Abstract
Activation-induced cytidine deaminase (AID) is essential for the generation of antibody memory but also targets oncogenes, among other genes. We investigated the transcriptional regulation of Aicda (which encodes AID) in class switch-inducible CH12F3-2 cells and found that Aicda regulation involved derepression by several layers of positive regulatory elements in addition to the 5' promoter region. The 5' upstream region contained functional motifs for the response to signaling by cytokines, the ligand for the costimulatory molecule CD40 or stimuli that activated the transcription factor NF-kappaB. The first intron contained functional binding elements for the ubiquitous silencers c-Myb and E2f and for the B cell-specific activator Pax5 and E-box-binding proteins. Our results show that Aicda is regulated by the balance between B cell-specific and stimulation-responsive elements and ubiquitous silencers.
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Affiliation(s)
- Thinh Huy Tran
- Department of Immunology and Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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13
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Birnbaum D, Sircoulomb F, Imbert J. A reason why the ERBB2 gene is amplified and not mutated in breast cancer. Cancer Cell Int 2009; 9:5. [PMID: 19226453 PMCID: PMC2649042 DOI: 10.1186/1475-2867-9-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 02/18/2009] [Indexed: 12/15/2022] Open
Abstract
Alterations of receptor-type tyrosine kinases (RTK) are frequent in human cancers. They can result from translocation, mutation or amplification. The ERBB2 RTK is encoded by a gene that is amplified in about 20% breast cancers. The question is: why is this RTK specifically subjected to this type of alteration? We propose that ERBB2 gene amplification is used to overcome repression of its expression by sequence-specific transcription factors.
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Affiliation(s)
- Daniel Birnbaum
- Centre de Recherche en Cancérologie de Marseille, UMR891 Inserm and Institut Paoli-Calmettes, Marseille, F-13009, France.
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14
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Liu JY, Chuang TC, Way TD, Tsai TC, Hu CL, Liu GY, Wang SS, Chung JG, Kao MC. The N-terminal domain of EBNA1 acts as a suppressor of the HER2/neu oncogene. Cancer Lett 2008; 273:273-80. [PMID: 18805633 DOI: 10.1016/j.canlet.2008.08.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Revised: 05/23/2008] [Accepted: 08/08/2008] [Indexed: 11/15/2022]
Abstract
HER2/neu oncogene-mediated malignancy is clearly associated with various human cancers. Therefore, HER2/neu targeting is an effective approach to cancer therapy. We have previously demonstrated that Epstein-Barr virus nuclear antigen-1 (EBNA1) can suppress HER2/neu oncogene expression, although EBNA1 itself has oncogenic potential. Here, we found that the N-terminal domain of EBNA1 alone, named EBNA1-NT, which contains the N-terminal region of amino acid residues 1-86 of EBNA1, is required and sufficient to suppress HER2/neu oncogene expression at the transcriptional level. Furthermore, in EBNA1-NT-transfected HER2/neu-overexpressing cells, we found EBNA1-NT could down-regulate the endogenous production of p185(HER2/neu), lower transformation ability, sensitize paclitaxel-induced apoptosis and decrease tumorigenic potential. These data suggest that EBNA1-NT may act as a repressor of the HER2/neu oncogene.
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Affiliation(s)
- Jah-Yao Liu
- Department of Obstetrics and Gynecology, Tri-Service General Hospital, Taipei, Taiwan
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15
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Kopecki Z, Luchetti MM, Adams DH, Strudwick X, Mantamadiotis T, Stoppacciaro A, Gabrielli A, Ramsay RG, Cowin AJ. Collagen loss and impaired wound healing is associated with c-Myb deficiency. J Pathol 2007; 211:351-61. [PMID: 17152050 DOI: 10.1002/path.2113] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Collagen type I serves as an abundant structural and signalling component of skin. It is also an established target gene of the transcription factor, c-Myb. When c-myb-/- embryos were examined it was observed that their skin was markedly thinner than normal. Importantly, immunohistochemical investigation showed complete absence of collagen type I. Although these homozygous knock-out embryos fail to develop beyond day 15, fibroblasts established from these embryos (mouse embryonic fibroblasts [MEFs]) show defective proliferative responses. Furthermore, in vitro scratch wound assays demonstrated that these c-myb-/- MEFs also exhibit slower closure than their wild-type counterparts. Embryonic lethality has meant that examination of the role of c-Myb in adult mouse skin has not been reported to date. However, in view of the abundance of collagen type I in normal skin, its role in skin integrity and the in vitro data showing proliferative and migration defects in c-myb-/- MEFs, we investigated the consequences of heterozygous c-myb loss in adult mice on the complex process of skin repair in response to injury. Our studies clearly demonstrate that heterozygous c-myb deficiency has a functional effect on wound repair, collagen type I levels and, in response to wounding, transforming growth factor-beta1 (an important collagen stimulating factor) induction expression is aberrantly high. Manipulation of c-Myb may therefore provide new therapeutic opportunities for improving wound repair while uncontrolled expression may underpin some fibrotic disorders.
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Affiliation(s)
- Z Kopecki
- Child Health Research Institute, North Adelaide, South Australia and School of Pharmacy and Medical Sciences, University of South Australia, Australia
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16
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Abstract
PURPOSE OF REVIEW Many noninherited or inherited variations have been described in fibrinogen and they may affect the different functions of fibrinogen. RECENT FINDINGS A number of the acquired variations in fibrinogen affect the properties of the fibrinogen molecule, such as the conversion rate to fibrin and/or the characteristics of the fibrin clot. Also, genetic polymorphisms are known that can affect the function of the fibrinogen molecule. In addition, some other genetic variants are associated with plasma levels of fibrinogen and with the increase of fibrinogen levels during an acute-phase reaction. SUMMARY In this review the authors discuss the noninherited and inherited variations of fibrinogen and the clinical implications (e.g. when determining the risk of cardiovascular disease).
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Affiliation(s)
- Moniek P M de Maat
- Department of Hematology, Erasmus Medical Center, Rotterdam, The Netherlands.
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17
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Petrovas C, Jeay S, Lewis RE, Sonenshein GE. B-Myb repressor function is regulated by cyclin A phosphorylation and sequences within the C-terminal domain. Oncogene 2003; 22:2011-20. [PMID: 12673206 DOI: 10.1038/sj.onc.1206231] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
B-Myb is a widely expressed member of the myb oncogene family that has been shown to act as either an activator or repressor of gene transcription in a cell-type-specific fashion. For example, in aortic smooth muscle cells B-Myb represses transcription of the alpha2(V) collagen gene. Recently, phosphorylation of B-Myb by cyclin A was shown to enhance greatly its ability to transactivate. Here, we have tested the effects of cyclin A on the ability of B-Myb to repress. We report that coexpression of cyclin A abolished repression of the alpha2(V) collagen promoter, whereas a dominant-negative cyclin-dependent kinase 2 (cdk2) enhanced repression by ectopic and endogenous B-Myb protein. Mutation of 10 of 22 putative cyclin A sites, which greatly reduces the effects of cyclin A on transactivation by B-Myb, had no effect on the ability of cyclin A to alleviate B-Myb-mediated repression of alpha2(V) collagen promoter activity. Furthermore, the stability of the mutant B-Myb protein was largely unaffected by cyclin A, although ectopic expression of cyclin A enhanced the rate of decay of wild-type B-Myb protein. Thus, the mechanisms of repression and activation appear distinct, for example, mediated by different critical phosphorylation sites or protein-protein interactions. B-Myb mutants with either deletion of aa 374-581 (B-Myb-Mut3) or C-terminal truncation beyond aa 491 (B-Myb-491) positively regulated alpha2(V) collagen promoter activity, and were not affected by cyclin A. Thus, our findings indicate that the ability of B-Myb to function as a repressor of matrix promoter activity is abolished by cyclin A, and maps the sites mediating negative regulation by B-Myb to the region between aa 491 and 582.
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18
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You XM, Mungrue IN, Kalair W, Afroze T, Ravi B, Sadi AM, Gros R, Husain M. Conditional expression of a dominant-negative c-Myb in vascular smooth muscle cells inhibits arterial remodeling after injury. Circ Res 2003; 92:314-21. [PMID: 12595344 DOI: 10.1161/01.res.0000056758.73215.5a] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inhibiting activity of the c-Myb transcription factor attenuates G1 to S phase cell cycle transitions in vascular smooth muscle cells (SMCs) in vitro. To determine the effects of arterial SMC-specific expression of a dominant-negative c-Myb molecule (Myb-Engrailed) on vascular remodeling in vivo, we performed carotid artery wire-denudation in 2 independent lines of binary transgenic mice with SM22alpha promoter-defined Doxycycline-suppressible expression of Myb-Engrailed. Adult mice with arterial SMC-specific expression of Myb-Engrailed were overtly normal in appearance and did not display any changes in cardiovascular structure or physiology. However, bromodeoxyuridine-defined arterial SMC proliferation, neointima formation, medial hyperplasia, and arterial remodeling were markedly decreased in mice expressing arterial SMC-restricted Myb-Engrailed after arterial injury. These data suggest that c-Myb activity in arterial SMCs is not essential for arterial structure or function during development, but is involved in the proliferation of arterial SMCs as occurs in vascular pathology, and that the expression of a dominant-negative c-Myb can dramatically reduce adverse arterial remodeling in an in vivo model of restenosis. As such, this model represents a novel tissue-specific strategy for the potential gene therapy of diseases characterized by arterial SMC proliferation.
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MESH Headings
- Animals
- Bromodeoxyuridine
- Carotid Stenosis/pathology
- Carotid Stenosis/prevention & control
- Cell Division/genetics
- Disease Models, Animal
- Gene Expression/drug effects
- Genes, Dominant
- Homeodomain Proteins/genetics
- Mice
- Mice, Transgenic
- Microfilament Proteins/genetics
- Muscle Proteins/genetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Promoter Regions, Genetic
- Proto-Oncogene Proteins c-myb/biosynthesis
- Proto-Oncogene Proteins c-myb/genetics
- Proto-Oncogene Proteins c-myb/pharmacology
- Tetracycline/pharmacology
- Transcription Factors
- Tunica Intima/drug effects
- Tunica Intima/metabolism
- Tunica Intima/pathology
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Affiliation(s)
- Xiao-Mang You
- Division of Cellular and Molecular Biology, The Toronto General Hospital Research Institute, Ontario, Canada
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19
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Chuang TC, Way TD, Lin YS, Lee YC, Law SL, Kao MC. The Epstein-Barr virus nuclear antigen-1 may act as a transforming suppressor of the HER2/neu oncogene. FEBS Lett 2002; 532:135-42. [PMID: 12459478 DOI: 10.1016/s0014-5793(02)03658-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is known that the HER2/neu proto-oncogene is associated with a wide variety of human cancers and considered to be an attractive target for developing anti-cancer agents. We report here for the first time that the Epstein-Barr virus nuclear antigen-1 (EBNA1) suppresses the HER2/neu oncogene expression at the transcriptional level. Recombinant clones of EBNA1 were subcloned and stably transfected into HER2/neu-overexpressing human ovarian cancer SKOV3.ip1 cells. These EBNA1-containing clones down-regulated the endogenous production of p185(HER2/neu). In addition, the EBNA1-expressing stable transfectants showed reduced growth rate, low soft agarose colony-forming ability and tumorigenic potential as compared with the parental line. These data suggest that EBNA1 may act as a transforming suppressor of the HER2/neu oncogene.
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Affiliation(s)
- Tzu-Chao Chuang
- Graduate Institute of Life Sciences, National Defense Medical Center, National Defense University, Taipei, Taiwan
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20
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Tanno B, Negroni A, Vitali R, Pirozzoli MC, Cesi V, Mancini C, Calabretta B, Raschellà G. Expression of insulin-like growth factor-binding protein 5 in neuroblastoma cells is regulated at the transcriptional level by c-Myb and B-Myb via direct and indirect mechanisms. J Biol Chem 2002; 277:23172-80. [PMID: 11973331 DOI: 10.1074/jbc.m200141200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuroblastoma (NB), a malignant childhood tumor deriving from the embryonic neural crest, is sensitive to the growth-stimulating effects of insulin-like growth factors (IGFs). Aggressive cases of this disease often acquire autocrine loops of IGF production, but the mechanisms through which the different components of the IGF axis are regulated in tumor cells remain unclear. Upon conditional expression of c-Myb in a NB cell line, we detected up-regulation of IGF1, IGF1 receptor, and insulin-like growth factor-binding protein 5 (IGFBP-5) expression. Analysis of the IGFBP-5 promoter revealed two potential Myb binding sites at position -59 to -54 (M1) and -429 to -424 (M2) from the transcription start site; both sites were bound by c-Myb and B-Myb in vitro and in vivo. Reporter assays carried out using the proximal region of the human IGFBP-5 promoter demonstrated that c-Myb and B-Myb enhanced transcription. However, site-directed mutagenesis and deletion of the Myb binding sites coupled with reporter assays revealed that M2 but not M1 was important for Myb-dependent transactivation of the IGFBP-5 promoter. The double mutant M1/M2 was still transactivated by c-Myb, suggesting the existence of Myb binding-independent mechanisms of IGFBP-5 promoter regulation. A constitutively active AKT transactivated the IGFBP-5 promoter, whereas the phosphatidylinositol 3-kinase inhibitor LY294002 suppressed it. Moreover, the kinase dead dominant negative K179M AKT mutant was able to inhibit transcription from the M2 and M1/M2 IGFBP-5 mutant promoters. Deletion analysis of the IGFBP-5 promoter revealed that the AKT-responsive region lies between nucleotides -334 and -83. Together, these data suggest that the Myb binding-independent transactivation of the IGFBP-5 promoter was due to the activation of the phosphatidylinositol 3-kinase/AKT pathway likely mediated by IGF1 receptor-dependent signals. Finally, IGFBP-5 was able to modulate proliferation of NB cells in a manner dependent on its concentration and on the presence of IGFs.
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Affiliation(s)
- Barbara Tanno
- Ente Nuove Tecnologie Energia Ambiente (ENEA), Section of Toxicology and Biomedical Sciences, Via Anguillarese 301, 00060 S. Maria di Galeria, Rome, Italy
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21
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Monticelli S, Ghittoni R, Kabesch M, Vercelli D. Myb proteins repress human Ig epsilon germline transcription by inhibiting STAT6-dependent promoter activation. Mol Immunol 2002; 38:1129-38. [PMID: 12044779 DOI: 10.1016/s0161-5890(02)00037-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cytokine-dependent induction of correctly spliced germline (GL) transcripts is required to target the appropriate switch region for class switch recombination. GL transcription is linked to the cell cycle and the number of cell divisions through mechanisms that have not been defined. The human proximal epsilon GL promoter contains an IL-4 responsive element (IL-4RE) that binds STAT6 and is sufficient to confer IL-4 inducibility to a heterologous promoter in transient transfection studies. We show herein that the IL-4RE contains a novel Myb binding motif that overlaps the 3' end of the STAT6 palindrome. EMSA analysis showed binding to the IL-4RE of endogenous Myb proteins expressed in BL-2 B cells and Jurkat T cells. However, double occupancy of a probe spanning both STAT6 and Myb binding motifs could not be detected. Thus, binding of either factor may prevent protein/DNA interactions at the other site, raising the possibility that Myb binding may interfere with STAT6-dependent activation of the IL-4RE. Indeed, cotransfection of A-Myb or c-Myb expression vectors in HEK293 and BL-2 cells suppressed STAT6-dependent transcription from a reporter construct containing four copies of the IL-4RE cloned upstream of a minimal thymidine kinase promoter. Most importantly, overexpression of A-Myb was sufficient to suppress IL-4-induced endogenous epsilon GL transcription in BL-2 cells. Our results indicate that Myb proteins, which are known to act as cell cycle sensors, may play an important mechanistic role in the in vivo regulation of epsilon GL transcription in human B cells.
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Affiliation(s)
- Silvia Monticelli
- Arizona Respiratory Center, College of Medicine, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724, USA
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22
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Reichman TW, Muñiz LC, Mathews MB. The RNA binding protein nuclear factor 90 functions as both a positive and negative regulator of gene expression in mammalian cells. Mol Cell Biol 2002; 22:343-56. [PMID: 11739746 PMCID: PMC134226 DOI: 10.1128/mcb.22.1.343-356.2002] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nuclear factor 90 (NF90) was originally isolated in a complex that binds to the antigen recognition response element (ARRE-2) present in the interleukin-2 promoter. To characterize the transcriptional properties of NF90 in mammalian cells, we examined its ability to modulate promoter function in cellular transfection assays. NF90-Gal4 fusion proteins inhibited transcription from the adenovirus major late promoter in a fashion that was dependent on Gal4 targeting. Conversely, NF90 activated the cytomegalovirus immediate-early promoter, to which it was not targeted. These effects required distinct but overlapping domains in the C terminus of NF90, which contains a functional nuclear localization signal and two double-stranded-RNA binding motifs. NF90 is present in cellular complexes together with the NF45 protein. Transfection assays showed that NF45 binds NF90 strongly and stimulates its ability to activate but not to inhibit gene expression. This report characterizes NF90 as both a positive and negative regulator of gene expression, depending on the promoter context, and suggests a role for NF45 as a regulator of NF90.
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Affiliation(s)
- Trevor W Reichman
- Department of Biochemistry and Molecular Biology, New Jersey Medical School and Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07013-2714, USA
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23
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Masselink H, Vastenhouw N, Bernards R. B-myb rescues ras-induced premature senescence, which requires its transactivation domain. Cancer Lett 2001; 171:87-101. [PMID: 11485831 DOI: 10.1016/s0304-3835(01)00631-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
B-myb, a ubiquitously expressed member of the myb gene family, is highly regulated throughout the cell cycle and appears to be required for cell cycle progression. In contrast to its relatives A-myb, c-myb, and v-myb, no transforming activity of B-myb has been reported thus far. We report here that B-myb can rescue senescence induced by an activated ras oncogene in rodent cells in vitro. We show that transformation by B-Myb involves its ability to activate transcription. Similar to other oncogenic transcription factors, such as c-Myc and E2F, we show that B-Myb also has repression activity. We demonstrate that the C-terminus of B-Myb can function as a repressor of transcription, that B-Myb interacts with the repressor molecules BS69 and N-CoR and that the repression function, like the transactivation domain, contributes to B-myb transformation.
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Affiliation(s)
- H Masselink
- Division of Molecular Carcinogenesis and Center for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
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24
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Bartley PA, Lutwyche JK, Gonda TJ. Identification and validation of candidate Myb target genes. Blood Cells Mol Dis 2001; 27:409-15. [PMID: 11259163 DOI: 10.1006/bcmd.2001.0398] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
While a considerable number of candidate Myb target genes have been reported to date, most of these are likely to play little or no role in transformation by myb oncogenes. Here we have used a conditionally myb-transformed myeloid cell line (ERMYB) to further examine Myb regulation of one candidate target gene--c-myc--that has the potential to affect cell proliferation. It was found that the major influence on c-myc expression was the presence of cytokine (GM-CSF) rather than Myb activity. We also describe the application of PCR-based subtractive hybridization and low-density cDNA array screening, in conjunction with the ERMYB line, to the identification of additional Myb target genes. Preliminary identification of a number of candidates is reported; these include myeloperoxidase, which is known to have essential Myb-binding sites in its regulatory region.
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Affiliation(s)
- P A Bartley
- Hanson Centre for Cancer Research, Division of Human Immunology, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA, 5000, Australia
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25
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Leu JH, Yan SJ, Lee TF, Chou CM, Chen ST, Hwang PP, Chou CK, Huang CJ. Complete genomic organization and promoter analysis of the round-spotted pufferfish JAK1, JAK2, JAK3, and TYK2 genes. DNA Cell Biol 2000; 19:431-46. [PMID: 10945233 DOI: 10.1089/10445490050085924] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have previously reported the isolation of the JAK1 gene from the round-spotted pufferfish. In the present study, we cloned and characterized genomic sequences encoding pufferfish JAK2, JAK3, and TYK2, which are other members of JAK family. To our knowledge, this is the first report to demonstrate the existence of four JAK genes in fish. All pufferfish JAK genes except JAK1 are composed of 24 exons; JAK1 has an additional exon. A comparison of the exon-intron organization of these genes revealed that the splice sites of JAK genes are nearly identical. In addition, all pufferfish JAK genes have one intron in the 5' untranslated region. Taken together, these data suggest that the pufferfish JAK genes may have evolved from a common ancestor. By 5' rapid amplification of cDNA ends and sequence analysis, we deduced the promoter regions for all JAK genes and found they do not contain typical TATA or CCAAT boxes but rather numerous other potential binding sites for transcription factors. Interestingly, the TYK2 gene is linked to CDC37 in a head-to-tail manner with a small intergenic region of 292 bp. Within this region, there are two potential binding sites for transcriptional factors such as c-Myb and NF-IL6. The putative promoter regions of all JAK genes were tested either in a carp CF cell line or in zebrafish embryos using CAT or lacZ as reporter genes. Both assays confirmed the transcriptional activities of these promoters in vitro and in vivo.
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Affiliation(s)
- J H Leu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
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26
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Afroze T, Husain M. c-Myb-binding sites mediate G(1)/S-associated repression of the plasma membrane Ca(2+)-ATPase-1 promoter. J Biol Chem 2000; 275:9062-9. [PMID: 10722757 DOI: 10.1074/jbc.275.12.9062] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We demonstrate that two Myb-binding sites of the mouse plasma membrane Ca(2+)-ATPase-1 (PMCA1) promoter are required for G(1)/S cell cycle stage-associated repression of PMCA1 promoter activity. Nuclear run-on experiments revealed G(1)/S-associated repression of PMCA1 transcription. Ribonuclease protection assays revealed two transcription initiation sites between two Myb-binding sites in the PMCA1 promoter. Gel shift assays showed that c-Myb can bind to wild-type but not point mutated Myb binding sequences of the PMCA1 promoter. Transient transfection assays using cell cycle-synchronized vascular smooth muscle cells (VSMC) and PMCA1 promoter-luciferase constructs showed a 2-fold decrease in reporter activity at G(1)/S as compared with G(0). Overexpression of wild-type c-Myb severely repressed PMCA1 promoter activity at both G(0) and G(1)/S while co-transfection of a dominant negative c-Myb, or a construct encoding an anti-c-Myb neutralizing antibody, completely abolished the repression seen at G(1)/S. Single nucleotide substitutions in the first, second, or both Myb-binding sites alleviated the G(1)/S-associated repression of PMCA1 promoter activity in transformed rat VSMC and primary mouse VSMC cultures. We conclude that c-Myb mediates G(1)/S-associated transcriptional repression of the PMCA1 Ca(2+) pump in rodent VSMC by direct binding to the PMCA1 promoter.
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Affiliation(s)
- T Afroze
- Centre for Cardiovascular Research, Toronto General Hospital, Toronto, Ontario, Canada
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27
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David-Cordonnier MH, Hamdane M, D'Halluin JC. c-Myb protein binds to the EP element of the HBV enhancer and regulates transcription in synergy with NF-M. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1446:82-92. [PMID: 10395921 DOI: 10.1016/s0167-4781(99)00070-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The hepatitis B virus (HBV) enhancer contains multiple active elements, one of which is the EP element, a 15 bp site important for its regulation by acting on other functional elements like the E site. The EP element, in the HBV enhancer context, contains two putative binding sites for c-myb family gene products. Electrophoretic mobility shift assays showed that the minimal c-Myb DNA-binding domain binds to the EP sequence. DNase I footprinting experiments revealed that only one consensus binding site was effectively protected. We found that c-Myb down-regulates transcription driving by the HBV enhancer in CAT assays performed in a haematopoietic (K562) and in a hepatic (HepG2) cell line. Interestingly, co-expression of both c-Myb and NF-M, a C/EBPbeta homologue which recognises the E element of the HBV enhancer, showed a synergistic transactivation of the HBV enhancer while, separately, each of them had an inhibitory effect on transcription in HepG2 and K562 cell lines, two cell types potentially infected by the hepatitis B virus.
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Affiliation(s)
- M H David-Cordonnier
- U 124 INSERM Onco-Hématologie Moléculaire, Institut de Recherches sur le Cancer de Lille, Place de Verdun, 59.045, Lille, France
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28
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Abstract
The v-myb oncogene of the avian myeloblastosis virus (AMV) is unique among known oncogenes in that it causes only acute leukemia in animals and transforms only hematopoietic cells in culture. AMV was discovered in the 1930s as a virus that caused a disease in chickens that is similar to acute myelogenous leukemia in humans (Hall et al., 1941). This avian retrovirus played an important role in the history of cancer research for two reasons. First, AMV was used to demonstrate that all oncogenic viruses did not contain a single cancer-causing principle. In particular, although both Rous sarcoma virus (RSV) and AMV could replicate in cultures of either embryonic fibroblasts or hematopoietic cells, RSV could transform only fibroblasts whereas AMV could transform only hematopoietic cells (Baluda, 1963; Durban and Boettiger, 1981a). Second, chickens infected with AMV develop remarkably high white counts and therefore their peripheral blood contains remarkably large quantities of viral particles (Beard, 1963). For this reason AMV was often used as a prototypic retrovirus in order to study viral assembly and later to produce large amounts of reverse transcriptase for both research and commercial purposes. Following the discovery of the v-src oncogene of RSV and the demonstration that it arose from the normal c-src proto-oncogene, a number of acute leukemia viruses were analysed by similar techniques and found to also contain viral oncogenes of cellular origin (Roussel et al., 1979). In the case of AMV, it was shown that almost the entire retroviral env gene had been replaced by a sequence of cellular origin (initially called mab or amv, but later renamed v-myb) (Duesberg et al., 1980; Souza et al., 1980). Remarkably, sequences contained in this myb oncogene were shared between AMV and the avian E26 leukemia virus, but were not contained in any other acutely transforming retroviruses. In addition, the E26 virus contained a second sequence of cellular origin (ets) that was unique. The E26 leukemia virus was first described in the 1960s and causes an acute erythroblastosis in chickens, more reminiscent of the disease caused by avian erythroblastosis virus (AEV) than by AMV (Ivanov et al., 1962).
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Affiliation(s)
- J S Lipsick
- Department of Pathology, Stanford University School of Medicine, California 94305-5324, USA
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29
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Affiliation(s)
- B Ganter
- Department of Pathology, Stanford University School of Medicine, California 94305, USA
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30
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Ess KC, Witte DP, Bascomb CP, Aronow BJ. Diverse developing mouse lineages exhibit high-level c-Myb expression in immature cells and loss of expression upon differentiation. Oncogene 1999; 18:1103-11. [PMID: 10023687 DOI: 10.1038/sj.onc.1202387] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The c-myb gene encodes a sequence specific transactivator that is required for fetal hematopoiesis, but its potential role in other tissues is less clear because of the early fetal demise of mice with targeted deletions of the c-myb gene and incomplete of knowledge about c-myb's expression pattern. In the hematopoietic system, c-Myb protein acts on target genes whose expression is restricted to individual lineages, despite Myb's presence and role in multiple immature lineages. This suggests that c-Myb actions within different cell type-specific contexts are strongly affected by combinatorial interactions. To consider the possibility of similar c-Myb actions could extend into non-hematopoietic systems in other cell and tissue compartments, we characterized c-myb expression in developing and adult mice using in situ hybridization and correlated this with stage-specific differentiation and mitotic activity. Diverse tissues exhibited strong c-myb expression during development, notably tooth buds, the thyroid primordium, developing trachea and proximal branching airway epithelium, hair follicles, hematopoietic cells, and gastrointestinal crypt epithelial cells. The latter three of these all maintained high expression into adulthood, but with characteristic restriction to immature cell lineages prior to their terminal differentiation. In all sites, during fetal and adult stages, loss of c-Myb expression correlated strikingly with the initiation of terminal differentiation, but not the loss of mitotic activity. Based on these data, we hypothesize that c-Myb's function during cellular differentiation is both an activator of immature gene expression and a suppressor of terminal differentiation in diverse lineages.
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Affiliation(s)
- K C Ess
- Division of Molecular and Developmental Biology Children's Hospital Research Foundation, University of Cincinnati, Ohio 45229, USA
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Bein K, Ware JA, Simons M. Myb-dependent regulation of thrombospondin 2 expression. Role of mRNA stability. J Biol Chem 1998; 273:21423-9. [PMID: 9694906 DOI: 10.1074/jbc.273.33.21423] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The nuclear transcription factor c-Myb, which is highly expressed in hematopoietic cells, has been shown to be functional in NIH 3T3 cells: cells that do not possess detectable levels of c-Myb. To identify endogenous target genes of c-Myb in fibroblasts, RNA isolated from NIH 3T3 cells stably transfected with a full-length or a dominant negative c-myb construct (GREMyb and GREMEn, respectively) was subjected to differential display analysis. 5'-Rapid amplification of cDNA ends of a selected band, sequencing, and a nucleotide homology search led to the identification of thrombospondin 2 (TSP 2) as the gene product repressed in GREMyb and induced in GREMEn cells. The pattern of TSP 2 expression during the cell cycle was consistent with c-myb-dependent regulation. The possibility that the identified transcript was TSP 1, a homologous product known to be repressed by v-Src, c-Jun, and v-Myc, was ruled out by using a TSP 2-specific DNA probe and by showing a distinct pattern of regulation of TSP 1 and TSP 2 expression. Nuclear run-on and TSP 2 promoter-reporter (chloramphenicol acetyltransferase) assays showed similar transcriptional levels in GREMyb and NIH 3T3 cells. However, mRNA stability studies showed a much shorter TSP 2 mRNA half-life in GREMyb compared with wild type NIH 3T3 cells, suggesting that c-myb affects TSP 2 expression via a post-transcriptional mechanism. The implications of a protooncogene-mediated suppression of TSP expression are discussed.
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Affiliation(s)
- K Bein
- Angiogenesis Research Center, Cardiovascular Division, Department of Medicine Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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Lee TC, Li L, Philipson L, Ziff EB. Myc represses transcription of the growth arrest gene gas1. Proc Natl Acad Sci U S A 1997; 94:12886-91. [PMID: 9371770 PMCID: PMC24233 DOI: 10.1073/pnas.94.24.12886] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/1997] [Indexed: 02/05/2023] Open
Abstract
Cell proliferation is regulated by the induction of growth promoting genes and the suppression of growth inhibitory genes. Malignant growth can result from the altered balance of expression of these genes in favor of cell proliferation. Induction of the transcription factor, c-Myc, promotes cell proliferation and transformation by activating growth promoting genes, including the ODC and cdc25A genes. We show that c-Myc transcriptionally represses the expression of a growth arrest gene, gas1. A conserved Myc structure, Myc box 2, is required for repression of gas1, and for Myc induction of proliferation and transformation, but not for activation of ODC. Activation of a Myc-estrogen receptor fusion protein by 4-hydroxytamoxifen was sufficient to repress gas1 gene transcription. These findings suggest that transcriptional repression of growth arrest genes, including gas1, is one step in promotion of cell growth by Myc.
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Affiliation(s)
- T C Lee
- Howard Hughes Medical Institute, Department of Biochemistry, New York University Medical Center, NY 10016, USA
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Kato A, Sugiura N, Saruta Y, Hosoiri T, Yasue H, Hirose S. Targeting of endopeptidase 24.16 to different subcellular compartments by alternative promoter usage. J Biol Chem 1997; 272:15313-22. [PMID: 9182559 DOI: 10.1074/jbc.272.24.15313] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Endopeptidase 24.16 or mitochondrial oligopeptidase, abbreviated here as EP 24.16 (MOP), is a thiol- and metal-dependent oligopeptidase that is found in multiple intracellular compartments in mammalian cells. From an analysis of the corresponding gene, we found that the distribution of the enzyme to appropriate subcellular locations is achieved by the use of alternative sites for the initiation of transcription. The pig EP 24.16 (MOP) gene spans over 100 kilobases and is organized into 16 exons. The core protein sequence is encoded by exons 5-16 which match perfectly with exons 2-13 of the gene for endopeptidase 24.15, another member of the thimet oligopeptidase family. These two sets of 11 exons share the same splice sites, suggesting a common ancestor. Multiple species of mRNA for EP 24.16 (MOP) were detected by the 5'-rapid amplification of cDNA ends and they were shown to have been generated from a single gene by alternative choices of sites for the initiation of transcription and splicing. Two types of transcript were prepared, corresponding to transcription from distal and proximal sites. Their expression in vitro in COS-1 cells indicated that they encoded two isoforms (long and short) which differed only at their amino termini: the long form contained a cleavable mitochondrial targeting sequence and was directed to mitochondria; the short form, lacking such a signal sequence, remained in the cytosol. The complex structure of the EP 24.16 (MOP) gene thus allows, by alternative promoter usage, a fine transcriptional regulation of coordinate expression, in the different subcellular compartments, of the two isoforms arising from a single gene.
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Affiliation(s)
- A Kato
- Department of Biological Sciences, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226, Japan
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Wolff L. Contribution of oncogenes and tumor suppressor genes to myeloid leukemia. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1332:F67-104. [PMID: 9196020 DOI: 10.1016/s0304-419x(97)00006-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- L Wolff
- Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, MD, USA.
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Bates NP, Hurst HC. Transcriptional regulation of type I receptor tyrosine kinases in the mammary gland. J Mammary Gland Biol Neoplasia 1997; 2:153-63. [PMID: 10882301 DOI: 10.1023/a:1026303814855] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The transcriptional regulation of the human EGFR3 and ERBB2 genes has been extensively studied, particularly in the context of their overexpression in breast cancer. Here we summarize published work detailing the transcription factors which interact with the promoters of these and the rat ERBB2 homologue, neu, genes and discuss their possible relevance to gene activation in cancer. In addition we review the biologically significant molecules which modulate expression of these genes and discuss the nuclear factors involved in mediating these responses. We also describe novel therapies which may result from these studies and highlight directions for future research into the control of expression of the EGFR and ERBB2 genes in the normal mammary gland and in breast cancer.
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Affiliation(s)
- N P Bates
- ICRF Oncology Unit, Royal Postgraduate Medical School, London, United Kingdom
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36
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De Bortoli M, Dati C. Hormonal regulation of type I receptor tyrosine kinase expression in the mammary gland. J Mammary Gland Biol Neoplasia 1997; 2:175-85. [PMID: 10882303 DOI: 10.1023/a:1026308015763] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Hormones guide mammary gland development and differentiation by regulating the expression of local growth factors and their receptors at the cell surface. In line with this principle the expression of the epidermal growth factor receptor (EGFR)3 and ErbB2 receptors varies in the mammary gland during pregnancy, following the changing hormonal profile. In breast cancer, expression of EGFR and ErbB2 is clearly related to the absence of estrogen and progesterone receptors. In breast cancer cells in vitro, the expression of these receptors is modulated by hormones and other growth-modulatory reagents. Moreover, transcriptional regulation of both EGFR and ERBB2 by estrogens has been demonstrated. The action of hormones may therefore result in the differential availability of individual ErbB family members at the cell surface, in this way determining the specific response of the cell to EGF-like factors and heregulins.
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Affiliation(s)
- M De Bortoli
- Department of Animal and Human Biology, University of Torino, Italy.
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37
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Affiliation(s)
- S A Ness
- Northwestern University, Department of Biochemistry, Molecular Biology and Cell Biology, Evanston, IL 60208-3500, USA.
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Dash AB, Orrico FC, Ness SA. The EVES motif mediates both intermolecular and intramolecular regulation of c-Myb. Genes Dev 1996; 10:1858-69. [PMID: 8756344 DOI: 10.1101/gad.10.15.1858] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The c-Myb transcription factor is a proto-oncoprotein whose latent transforming activity can be unmasked by truncation of either terminus. Because both ends of Myb are involved in negative regulation, we tested whether they could associate in a two-hybrid assay and identified a carboxy-terminal motif that interacts with the amino-terminal DNA-binding domain. The EVES motif is highly conserved in vertebrate c-Myb proteins and contains a known site of phosphorylation previously implicated in the negative regulation of c-Myb. Interestingly, a related EVES motif is present in p100, a ubiquitously expressed transcriptional coactivator found in diverse species. We show that p100 interacts with and influences the activity of c-Myb, implicating it in the regulation of c-Myb, differentiation, and cell growth. Our results suggest that Myb is regulated by a novel mechanism in which intramolecular interactions and conformational changes control the intermolecular associations among Myb, p100, and the transcriptional apparatus.
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Affiliation(s)
- A B Dash
- Northwestern University, Department of Biochemistry, Molecular Biology and Cell Biology, Evanston, Illinois 60208-3500, USA
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Golay J, Basilico L, Loffarelli L, Songia S, Broccoli V, Introna M. Regulation of hematopoietic cell proliferation and differentiation by the myb oncogene family of transcription factors. INTERNATIONAL JOURNAL OF CLINICAL & LABORATORY RESEARCH 1996; 26:24-32. [PMID: 8739852 DOI: 10.1007/bf02644770] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The myb family of genes include the virally encoded v-myb oncogene, its normal cellular equivalent c-myb and two related members called A-myb and B-myb. They are all transcription factors that recognize the same DNA sequence (PyAACG/TG) and are all involved in the regulation of proliferation and differentiation in different cell types, including hematopoietic cells. C-myb is most highly expressed in hematopoietic cells and its oncogenic activation leads to transformation of these cells. Several lines of evidence have demonstrated that c-myb regulates both the proliferation and differentiation of hematopoietic cells of different lineages. The mechanisms of action of c-myb and v-myb are becoming clearer, mostly through the study of the different genes that are regulated by these transcription factors and the cofactors with which c-myb and v-myb co-operate. More recently the biological and biochemical functions of the B-myb and A-myb gene products have been investigated. Evidence for the function of the different members of the myb family in relation to hematopoietic proliferation and differentiation is presented, and the different roles of the myb genes are discussed.
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Affiliation(s)
- J Golay
- Department of Immunology and Cell Biology, Istituto Ricerche Farmacologiche, Mario Negri, Milan, Italy
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40
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Deng QL, Ishii S, Sarai A. Binding site analysis of c-Myb: screening of potential binding sites by using the mutation matrix derived from systematic binding affinity measurements. Nucleic Acids Res 1996; 24:766-74. [PMID: 8604322 PMCID: PMC145691 DOI: 10.1093/nar/24.4.766] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The c-Myb oncoprotein is known to bind to multiple sites in the promoters of target genes. We have developed a protocol to screen the binding site of c-Myb by using the systematic binding data derived form measurements of binding affinity for oligonucleotide containing a known Myb-binding site and its complete single mutants. We first applied the method to predict the binding affinity for the known binding sites and compared with available experimental data. The predicated binding sites agree with many putative binding sites of known target promoters. However, there are some binding sites not predicated by the analysis. These sequences deviate from the consensus sequence derived from the binding analyses. In the light of the structure of Myb-DNA complex, these results indicate that different DNA-binding modes may be used by c-Myb to recognize different classes of binding sites. We also screened the sequence database for potential Myb-binding sites, and found sequences of several promoters that have not been identified experimentally but could be the target for c-Myb.
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Affiliation(s)
- Q L Deng
- Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Tsukuba, Ibaraki 305, Japan
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41
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Kanei-Ishii C, Nomura T, Ogata K, Sarai A, Yasukawa T, Tashiro S, Takahashi T, Tanaka Y, Ishii S. Structure and function of the proteins encoded by the myb gene family. Curr Top Microbiol Immunol 1996; 211:89-98. [PMID: 8585968 DOI: 10.1007/978-3-642-85232-9_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- C Kanei-Ishii
- Tsukuba Life Science Center, Institute of Physical & Chemical Research (RIKEN), Ibaraki, Japan
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