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Do C, Jiang G, Cova G, Katsifis CC, Narducci DN, Yang J, Sakellaropoulos T, Vidal R, Lhoumaud P, Tsirigos A, Regis FFD, Kakabadze N, Nora EP, Noyes M, Cheng X, Hansen AS, Skok JA. Brain and cancer associated binding domain mutations provide insight into CTCF's relationship with chromatin and its ability to act as a chromatin organizer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.11.575070. [PMID: 38370764 PMCID: PMC10871189 DOI: 10.1101/2024.01.11.575070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Although only a fraction of CTCF motifs are bound in any cell type, and approximately half of the occupied sites overlap cohesin, the mechanisms underlying cell-type specific attachment and ability to function as a chromatin organizer remain unknown. To investigate the relationship between CTCF and chromatin we applied a combination of imaging, structural and molecular approaches, using a series of brain and cancer associated CTCF mutations that act as CTCF perturbations. We demonstrate that binding and the functional impact of WT and mutant CTCF depend not only on the unique properties of each protein, but also on the genomic context of bound sites. Our studies also highlight the reciprocal relationship between CTCF and chromatin, demonstrating that the unique binding properties of WT and mutant proteins have a distinct impact on accessibility, TF binding, cohesin overlap, chromatin interactivity and gene expression programs, providing insight into their cancer and brain related effects. Graphical abstract
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Exploring Genetic Factors Involved in Huntington Disease Age of Onset: E2F2 as a New Potential Modifier Gene. PLoS One 2015; 10:e0131573. [PMID: 26148071 PMCID: PMC4493078 DOI: 10.1371/journal.pone.0131573] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 06/03/2015] [Indexed: 01/09/2023] Open
Abstract
Age of onset (AO) of Huntington disease (HD) is mainly determined by the length of the CAG repeat expansion (CAGexp) in exon 1 of the HTT gene. Additional genetic variation has been suggested to contribute to AO, although the mechanism by which it could affect AO is presently unknown. The aim of this study is to explore the contribution of candidate genetic factors to HD AO in order to gain insight into the pathogenic mechanisms underlying this disorder. For that purpose, two AO definitions were used: the earliest age with unequivocal signs of HD (earliest AO or eAO), and the first motor symptoms age (motor AO or mAO). Multiple linear regression analyses were performed between genetic variation within 20 candidate genes and eAO or mAO, using DNA and clinical information of 253 HD patients from REGISTRY project. Gene expression analyses were carried out by RT-qPCR with an independent sample of 35 HD patients from Basque Country Hospitals. We found suggestive association signals between HD eAO and/or mAO and genetic variation within the E2F2, ATF7IP, GRIN2A, GRIN2B, LINC01559, HIP1 and GRIK2 genes. Among them, the most significant was the association between eAO and rs2742976, mapping to the promoter region of E2F2 transcription factor. Furthermore, rs2742976 T allele patient carriers exhibited significantly lower lymphocyte E2F2 gene expression, suggesting a possible implication of E2F2-dependent transcriptional activity in HD pathogenesis. Thus, E2F2 emerges as a new potential HD AO modifier factor.
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Chalei V, Sansom SN, Kong L, Lee S, Montiel JF, Vance KW, Ponting CP. The long non-coding RNA Dali is an epigenetic regulator of neural differentiation. eLife 2014; 3:e04530. [PMID: 25415054 PMCID: PMC4383022 DOI: 10.7554/elife.04530] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 11/21/2014] [Indexed: 12/11/2022] Open
Abstract
Many intergenic long noncoding RNA (lncRNA) loci regulate the expression of adjacent protein coding genes. Less clear is whether intergenic lncRNAs commonly regulate transcription by modulating chromatin at genomically distant loci. Here, we report both genomically local and distal RNA-dependent roles of Dali, a conserved central nervous system expressed intergenic lncRNA. Dali is transcribed downstream of the Pou3f3 transcription factor gene and its depletion disrupts the differentiation of neuroblastoma cells. Locally, Dali transcript regulates transcription of the Pou3f3 locus. Distally, it preferentially targets active promoters and regulates expression of neural differentiation genes, in part through physical association with the POU3F3 protein. Dali interacts with the DNMT1 DNA methyltransferase in mouse and human and regulates DNA methylation status of CpG island-associated promoters in trans. These results demonstrate, for the first time, that a single intergenic lncRNA controls the activity and methylation of genomically distal regulatory elements to modulate large-scale transcriptional programmes.
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Affiliation(s)
- Vladislava Chalei
- MRC Functional Genomics
Unit, Department of Physiology, Anatomy and Genetics,
University of Oxford, Oxford, United
Kingdom
| | - Stephen N Sansom
- MRC Functional Genomics
Unit, Department of Physiology, Anatomy and Genetics,
University of Oxford, Oxford, United
Kingdom
- Computational Genomics
Analysis and Training Programme, University of
Oxford, Oxford, United Kingdom
| | - Lesheng Kong
- MRC Functional Genomics
Unit, Department of Physiology, Anatomy and Genetics,
University of Oxford, Oxford, United
Kingdom
| | - Sheena Lee
- Department of
Physiology, Anatomy and Genetics, University of
Oxford, Oxford, United Kingdom
| | - Juan F Montiel
- MRC Functional Genomics
Unit, Department of Physiology, Anatomy and Genetics,
University of Oxford, Oxford, United
Kingdom
| | - Keith W Vance
- MRC Functional Genomics
Unit, Department of Physiology, Anatomy and Genetics,
University of Oxford, Oxford, United
Kingdom
| | - Chris P Ponting
- MRC Functional Genomics
Unit, Department of Physiology, Anatomy and Genetics,
University of Oxford, Oxford, United
Kingdom
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Vance KW, Sansom SN, Lee S, Chalei V, Kong L, Cooper SE, Oliver PL, Ponting CP. The long non-coding RNA Paupar regulates the expression of both local and distal genes. EMBO J 2014; 33:296-311. [PMID: 24488179 PMCID: PMC3983687 DOI: 10.1002/embj.201386225] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Although some long noncoding RNAs (lncRNAs) have been shown to regulate gene expression in cis, it remains unclear whether lncRNAs can directly regulate transcription in trans by interacting with chromatin genome-wide independently of their sites of synthesis. Here, we describe the genomically local and more distal functions of Paupar, a vertebrate-conserved and central nervous system-expressed lncRNA transcribed from a locus upstream of the gene encoding the PAX6 transcription factor. Knockdown of Paupar disrupts the normal cell cycle profile of neuroblastoma cells and induces neural differentiation. Paupar acts in a transcript-dependent manner both locally, to regulate Pax6, as well as distally by binding and regulating genes on multiple chromosomes, in part through physical association with PAX6 protein. Paupar binding sites are enriched near promoters and can function as transcriptional regulatory elements whose activity is modulated by Paupar transcript levels. Our findings demonstrate that a lncRNA can function in trans at transcriptional regulatory elements distinct from its site of synthesis to control large-scale transcriptional programmes.
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Affiliation(s)
- Keith W Vance
- MRC Functional Genomics Unit, University of Oxford, Oxford UK
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Osinalde N, Olea M, Mitxelena J, Aloria K, Rodriguez JA, Fullaondo A, Arizmendi JM, Zubiaga AM. The nuclear protein ALY binds to and modulates the activity of transcription factor E2F2. Mol Cell Proteomics 2013; 12:1087-98. [PMID: 23297349 DOI: 10.1074/mcp.m112.024158] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
E2F transcription factors control the expression of genes involved in a variety of essential cellular processes and consequently their activity needs to be tightly regulated. Protein-protein interactions are thought to be key modulators of E2F activity. To gain insight into the mechanisms that regulate the activity of E2F2, we searched for novel proteins that associate with this transcription factor. We show that the nuclear protein ALY (THO complex 4), originally described as a transcriptional co-activator, associates with DNA-bound E2F2 and represses its transcriptional activity. The capacity of ALY to modulate gene expression was analyzed with expression microarrays by characterizing the transcriptome of E2F2 expressing HEK293T cells in which ALY was either overexpressed or silenced. We show that ALY influences the expression of more than 400 genes, including 98 genes bearing consensus E2F motifs. Thus, ALY emerges as a novel E2F2-interacting protein and a relevant modulator of E2F-responsive gene expression.
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Affiliation(s)
- Nerea Osinalde
- Department of Biochemistry and Molecular Biology, University of the Basque Country, UPV/EHU, 48940 Leioa, Spain
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Tomikawa J, Shimokawa H, Uesaka M, Yamamoto N, Mori Y, Tsukamura H, Maeda KI, Imamura T. Single-stranded noncoding RNAs mediate local epigenetic alterations at gene promoters in rat cell lines. J Biol Chem 2011; 286:34788-99. [PMID: 21844201 PMCID: PMC3186369 DOI: 10.1074/jbc.m111.275750] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 07/21/2011] [Indexed: 01/26/2023] Open
Abstract
A growing number of noncoding RNAs (ncRNAs) are thought to be involved in sequence-specific alterations of epigenetic processes, mostly causing gene repression. In this study, promoter-associated ncRNAs (pancRNAs >200 nucleotides in size) that were endogenously generated from the sense strand at Map2b, antisense strand at Nefl, and both strands at Vim were investigated regarding their epigenetic potential as positive or negative regulators in rat pheochromocytoma (PC12) and fibroblast (normal rat kidney) cell lines. The respective antisense pancRNAs were associated with several active chromatin marks at the Nefl and Vim promoters. Forced expression of fragments expressing the antisense pancRNAs caused sequence-specific DNA demethylation, whereas a decrease of expression induced methylation of the same sequences. In contrast, perturbing the expression of the two sense pancRNAs did not change the DNA methylation status. These results suggest that a fraction of naturally occurring ncRNAs acts in cis as a single-stranded form and that the transcriptional orientation of pancRNA is important for the establishment of sequence-specific epigenetic modifications consistent with open chromatin structure.
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Affiliation(s)
- Junko Tomikawa
- From the Division of Behavioral Biology, National Institute for Basic Biology, Nishigonaka 38, Okazaki 444-8585
- the Laboratory of Reproductive Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601
| | - Hiroko Shimokawa
- From the Division of Behavioral Biology, National Institute for Basic Biology, Nishigonaka 38, Okazaki 444-8585
- the Laboratory of Reproductive Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601
| | - Masahiro Uesaka
- the Laboratory for Biodiversity, Global COE Program, Division of Biological Science, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, and
| | - Naoki Yamamoto
- the Laboratory for Biodiversity, Global COE Program, Division of Biological Science, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, and
| | - Yuji Mori
- From the Division of Behavioral Biology, National Institute for Basic Biology, Nishigonaka 38, Okazaki 444-8585
- the Laboratory of Veterinary Ethology, Animal Resource Sciences/Veterinary Medical Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hiroko Tsukamura
- From the Division of Behavioral Biology, National Institute for Basic Biology, Nishigonaka 38, Okazaki 444-8585
- the Laboratory of Reproductive Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601
| | - Kei-ichiro Maeda
- the Laboratory of Reproductive Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601
| | - Takuya Imamura
- From the Division of Behavioral Biology, National Institute for Basic Biology, Nishigonaka 38, Okazaki 444-8585
- the Laboratory for Biodiversity, Global COE Program, Division of Biological Science, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, and
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Delgado I, Fresnedo O, Iglesias A, Rueda Y, Syn WK, Zubiaga AM, Ochoa B. A role for transcription factor E2F2 in hepatocyte proliferation and timely liver regeneration. Am J Physiol Gastrointest Liver Physiol 2011; 301:G20-31. [PMID: 21527726 DOI: 10.1152/ajpgi.00481.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
E2F transcription factors are key regulators of the cell cycle although the relative contribution of each E2F member in regulating cellular proliferation is still poorly defined. Present evidence suggests that E2F2 may act both as a suppressor and promoter of proliferation, depending on the cellular context. We used a loss-of-function mutant mouse model to investigate the function of E2F2 in liver regeneration after partial hepatectomy, a paradigm of cell-cycle progression. Liver mass recovery and histology were examined over 9 days in 70% hepatectomized E2F2(-/-) and wild-type animals. Transcriptome analysis was performed in quiescent and 48-h regenerating liver samples. TIGR MultiExperiment Viewer was used for the statistical analysis of microarray data, significance was determined by Fischer, and P values were adjusted applying Benjamini-Hochberg multiple-testing correction. We show that E2F2 is required for adult hepatocyte proliferation and for timely liver regeneration, as disruption of the E2F2 gene in hepatocytes leads to a reduced rate of S-phase entry and to delayed liver regeneration. Transcriptome analysis followed by ontological classification of differentially expressed genes and gene-interaction network analysis indicated that the majority of genes involved in normal liver regeneration were related to biosynthetic and catabolic processes of all major biomolecules as well as cellular location and intracellular transport, confirming the complex nature of the regeneration process. Remarkably, transcripts of genes included in functional categories that are crucial for cell cycle, apoptosis and wound-healing response, and fibrosis were absent in the transcriptome of posthepatectomized E2F2(-/-) mice. Our results indicate that the transcriptional activity of E2F2 contributes to promote adult hepatocyte proliferation and liver regeneration.
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Affiliation(s)
- Igotz Delgado
- Departments of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Sarriena s/n, Leioa, Spain
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Liu XH, Xu W, Russ J, Eiden LE, Eiden MV. The host range of gammaretroviruses and gammaretroviral vectors includes post-mitotic neural cells. PLoS One 2011; 6:e18072. [PMID: 21464894 PMCID: PMC3065480 DOI: 10.1371/journal.pone.0018072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 02/20/2011] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Gammaretroviruses and gammaretroviral vectors, in contrast to lentiviruses and lentiviral vectors, are reported to be restricted in their ability to infect growth-arrested cells. The block to this restriction has never been clearly defined. The original assessment of the inability of gammaretroviruses and gammaretroviral vectors to infect growth-arrested cells was carried out using established cell lines that had been growth-arrested by chemical means, and has been generalized to neurons, which are post-mitotic. We re-examined the capability of gammaretroviruses and their derived vectors to efficiently infect terminally differentiated neuroendocrine cells and primary cortical neurons, a target of both experimental and therapeutic interest. METHODOLOGY/PRINCIPAL FINDINGS Using GFP expression as a marker for infection, we determined that both growth-arrested (NGF-differentiated) rat pheochromocytoma cells (PC12 cells) and primary rat cortical neurons could be efficiently transduced, and maintained long-term protein expression, after exposure to murine leukemia virus (MLV) and MLV-based retroviral vectors. Terminally differentiated PC12 cells transduced with a gammaretroviral vector encoding the anti-apoptotic protein Bcl-xL were protected from cell death induced by withdrawal of nerve growth factor (NGF), demonstrating gammaretroviral vector-mediated delivery and expression of genes at levels sufficient for therapeutic effect in non-dividing cells. Post-mitotic rat cortical neurons were also shown to be susceptible to transduction by murine replication-competent gammaretroviruses and gammaretroviral vectors. CONCLUSIONS/SIGNIFICANCE These findings suggest that the host range of gammaretroviruses includes post-mitotic and other growth-arrested cells in mammals, and have implications for re-direction of gammaretroviral gene therapy to neurological disease.
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Affiliation(s)
- Xiu-Huai Liu
- Section on Molecular Neuroscience, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Wenqin Xu
- Section on Directed Gene Transfer, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jill Russ
- Section on Directed Gene Transfer, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lee E. Eiden
- Section on Molecular Neuroscience, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Maribeth V. Eiden
- Section on Directed Gene Transfer, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, United States of America
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Abstract
Zinc is essential for normal brain development. Gestational severe zinc deficiency can lead to overt fetal brain malformations. Although not teratogenic, suboptimal zinc nutrition during gestation can have long-term effects on the offspring's nervous system. This article will review current knowledge on the role of zinc in modulating neurogenesis and neuronal apoptosis as well as the proposed underlying mechanisms. A decrease in neuronal zinc causes cell cycle arrest, which in part involves a deregulation of select signals (ERK1/2, p53, and NF-kappaB). Zinc deficiency also induces apoptotic neuronal death through the intrinsic (mitochondrial) pathway, which can be triggered by the activation of the zinc-regulated enzyme caspase-3, and as a consequence of abnormal regulation of prosurvival signals (ERK1/2 and NF-kappaB). Alterations in the finely tuned processes of neurogenesis, neuronal migration, differentiation, and apoptosis, which involve the developmental shaping of the nervous system, could have a long-term impact on brain health. Zinc deficiency during gestation, even at the marginal levels observed in human populations, could increase the risk for behavioral/neurological disorders in infancy, adolescence, and adulthood.
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Affiliation(s)
- Ana M. Adamo
- Department of Biological Chemistry, IQUIFIB (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina
| | - Patricia I. Oteiza
- Department of Nutrition, University of California, Davis CA 95616, USA
- Department of Environmental Toxicology, University of California, Davis CA 95616, USA
- To whom correspondence should be addressed: Dr. Patricia I. Oteiza, Department of Nutrition, University of California, Davis, One Shields Av., Davis, CA, 95616, USA, Phone: 530-754-6074, Fax: 530-752-8966,
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Chandran NS, Vunnava P, Wu Y, Kapatos G. Specificity proteins Sp1 and Sp3 interact with the rat GTP cyclohydrolase I proximal promoter to regulate transcription. J Neurochem 2008; 104:1233-48. [PMID: 18004997 PMCID: PMC2265209 DOI: 10.1111/j.1471-4159.2007.05054.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The role of the proximal promoter GC-box in regulating basal and cAMP-dependent GTP Cyclohydrolase I gene transcription was investigated using a variety of cell lines and techniques. These studies show that the GC-box is composed of a triad of cis-elements that in vitro bind specificity proteins Sp1 and Sp3. Sp1 and Sp3 were found associated with the native proximal promoter in PC12 cells but were not recruited to the promoter during cAMP-dependent transcription. Studies using Drosophila SL2 cells showed that Sp3 occupies two sites within the GC-box and enhances transcription when acting alone and synergistically when combined with nuclear factor-Y (NF-Y) and CCAAT/Enhancer-Binding Protein (C/EBP)beta, cognate binding proteins for the adjacent cAMP response element (CRE) and CCAAT-box cAMP response elements. In contrast, Sp1 bound only one site within the GC-box and did not enhance transcription unless combined with NF-Y and C/EBPbeta. Studies in SL2 cells also showed that Sp1 and Sp3 do not co-occupy the GC-box, and accordingly Sp1 competes for Sp3 binding to repress Sp3-dependent transcription. In PC12 cells, complete mutation of the GC-box reduced basal but not cAMP-dependent transcription, resulting in an overall increase in the cAMP response and demonstrating that formation of this enhanceosome does not require Sp1 or Sp3. Experiments in which the GC-box was replaced with a Gal4 element and the promoter challenged with Gal4 fusion proteins support this conclusion and a role for Sp3 in maintaining high levels of basal transcription in PC12 cells. Equivalent amounts of Sp1 and Sp3 were found associated with the native proximal promoter in PC12 and Rat2 cells, which differ 10-fold in basal transcription. Similar levels of methylation of CpG dinucleotides located within the GC-box were also observed in these two cells lines. These results suggest that Sp1 and Sp3 bound to the GC-box might help to preserve an open chromatin configuration at the proximal promoter in cells which constitutively express low levels of GTP Cyclohydrolase I.
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Affiliation(s)
- Nitya Sarath Chandran
- Cellular and Clinical Neurobiology Program, Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Prashanthi Vunnava
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Yanning Wu
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Gregory Kapatos
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, USA
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Deregulated E2f-2 underlies cell cycle and maturation defects in retinoblastoma null erythroblasts. Mol Cell Biol 2007; 27:8713-28. [PMID: 17923680 DOI: 10.1128/mcb.01118-07] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
By assessing the contribution of deregulated E2F activity to erythroid defects in Rb null mice, we have identified E2f-2 as being upregulated in end-stage red cells, where we show it is the major pRb-associated E2f and the predominant E2f detected at key target gene promoters. Consistent with its expression pattern, E2f-2 loss restored terminal erythroid maturation to Rb null red cells, including the ability to undergo enucleation. Deletion of E2f-2 also extended the life span of Rb null mice despite persistent defects in placental development, indicating that deregulated E2f-2 activity in differentiating erythroblasts contributes to the premature lethality of Rb null mice. We show that the aberrant entry of Rb null erythroblasts into S phase at times in differentiation when wild-type erythroblasts are exiting the cell cycle is inhibited by E2f-2 deletion. E2f-2 loss induced cell cycle arrest in both wild-type and Rb null erythroblasts and was associated with increased DNA double-strand breaks. These results implicate deregulated E2f-2 in the cell cycle defects observed in Rb null erythroblasts and reveal a novel role for E2f-2 during terminal red blood cell differentiation. The identification of a tissue-restricted role for E2f-2 in erythropoiesis highlights the nonredundant nature of E2f transcription factor activities in cell growth and differentiation.
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Kodama Y, Murakumo Y, Ichihara M, Kawai K, Shimono Y, Takahashi M. Induction of CRMP-2 by GDNF and analysis of the CRMP-2 promoter region. Biochem Biophys Res Commun 2004; 320:108-15. [PMID: 15207709 DOI: 10.1016/j.bbrc.2004.05.139] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Indexed: 10/26/2022]
Abstract
Collapsin response mediator protein-2 (CRMP-2) is a mammalian homologue of UNC-33 of Caenorhabditis elegans. Mutations of CRMP-2 result in abnormal axon termination. Recently, it was demonstrated that CRMP-2 binds to tubulin heterodimers to promote microtubule assembly that is critical for axonal differentiation and growth during development. Here we show that glial cell line-derived neurotrophic factor (GDNF) enhances CRMP-2 expression in TGW human neuroblastoma cells via activation of RET receptor tyrosine kinase. GDNF-mediated CRMP-2 expression was regulated mainly by the extracellular regulated kinase (ERK) pathway, but was independent of activation of phosphatidylinositol 3-kinase and Src family kinases. Analysis of the promoter region of the CRMP-2 gene revealed that the region 214-48 bp upstream of the transcriptional start site is important for CRMP-2 expression. The SP1, E2F, and GATA1/2 binding sites appeared to play some roles in regulation of CRMP-2 expression. As expected, the CRMP-2 protein accumulated in extended neurites of TGW cells treated with GDNF. However, neuritogenesis of TGW cells was mostly dependent on Src family kinase activity and not ERK activity, indicating that the increased expression of CRMP-2 alone was not sufficient for neuritogenesis.
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Affiliation(s)
- Yoshinori Kodama
- Department of Pathology, Nagoya University Graduate School of Medicine, Japan
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Sakai K, Kitagawa Y, Saiki S, Saiki M, Hirose G. Effect of a paraneoplastic cerebellar degeneration-associated neural protein on B-myb promoter activity. Neurobiol Dis 2004; 15:529-33. [PMID: 15056460 DOI: 10.1016/j.nbd.2003.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2003] [Revised: 10/02/2003] [Accepted: 11/04/2003] [Indexed: 11/18/2022] Open
Abstract
In this study, we have shown that a paraneoplastic cerebellar degeneration (PCD)-associated antigen, pcd17, binds to a cell cycle-related protein, MRG15. MRG15 derepresses the E2F-responsive B-myb promoter. The pcd17 antigen inhibits the derepression of the B-myb transcriptional activity by MRG15, and, as a result, pcd17 represses the promoter. Delivery of anti-Purkinje cell antibodies (anti-Yo) into the cells inhibits the repression of B-myb promoter activity by pcd17. Because derepression of the B-myb promoter has been implicated in neuronal death, the results suggest the possible role of the antibodies in the pathogenesis of PCD.
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Affiliation(s)
- Koichiro Sakai
- Department of Neurology, Kanazawa Medical University, Kahoku-gun, 920-0293 Ishikawa, Japan.
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14
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Woo CW, Lucarelli E, Thiele CJ. NGF activation of TrkA decreases N-myc expression via MAPK path leading to a decrease in neuroblastoma cell number. Oncogene 2004; 23:1522-30. [PMID: 14691455 DOI: 10.1038/sj.onc.1207267] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In neuroblastoma (NB), expression of the TrkA receptor is correlated with good prognosis while N-myc amplification is correlated with poor prognosis. Decreased N-myc levels are key to controlling growth and inducing differentiation in NB cells. In this report, we detail mechanisms by which nerve growth factor (NGF) decreases N-myc levels in TrkA-transfected NB cells and its effect on NB cell proliferation. NGF induced a decrease in N-myc mRNA within 1 h of treatment that occurred in the presence of cycloheximide. The stability of N-myc mRNA was not affected by NGF, indicating a transcriptional control of N-myc mRNA by NGF. NGF but not brain-derived neurotrophic factor (BDNF) decreased N-myc levels demonstrating that p75 alone was not involved. The NGF-induced decrease in N-myc expression was blocked by the Trk tyrosine kinase (TK) antagonist K252a indicating that signals transduced by Trk TK downstream targets were involved. Pharmacologic inhibitors implicated the mitogen-activated protein kinase (MAPK) path. This was supported by the finding that expression of a constitutively activated component of the MAPK path, MAPK kinase (MEK), decreased N-myc levels. Alterations in the level of N-myc are known to alter NB cell cycle progression by affecting the levels of E2Fs and p27(kip1). Consistent with these findings, NGF decreased NB cell number and decreased cyclin E-dependent kinase activity via an increase in p27(kip1). Thus, our results indicate that the MAP kinase is selectively involved in the NGF-induced N-myc downregulation through a transcriptional mechanism. Furthermore, NGF affects the time required for 15N TrkA cells to complete a replication cycle by decreasing N-myc, E2Fs, cyclin E kinase activity and increasing p27(kip1) binding to cyclin E kinase.
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Affiliation(s)
- Chan-Wook Woo
- Cell & Molecular Biology Section, Pediatric Oncology Branch, NCI, NIH, Bethesda, MD 20892, USA
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15
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Schmehil AL, Levin LA. Transient transfection protects PC6-3 cells from apoptosis induced by nerve growth factor deprivation. Neuroscience 2003; 116:23-9. [PMID: 12535934 DOI: 10.1016/s0306-4522(02)00558-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Some mammalian neurons undergo apoptosis after neurotrophin deprivation. We studied neuronally differentiated PC6-3 pheochromocytoma cells, which are highly dependent on nerve growth factor for survival. We found that transient transfection with green fluorescent protein or beta-galactosidase protected cells from apoptosis induced by nerve growth factor deprivation. Individual transfection reagent components did not produce increased viability of nerve growth factor-deprived cells. This apparent neuroprotective effect from transient transfection was specific to neurotrophin deprivation, as cells treated with H(2)O(2) or staurosporine were not protected. To determine the mechanism of neuroprotection after transfection, the transfection status of identified groups of cells was assessed both before and after nerve growth factor deprivation. The results were consistent with a model whereby cells that are transfected but not yet expressing the transfected protein are relatively protected from nerve growth factor deprivation. We suggest that apoptosis induced by neurotrophin deprivation may interact with processes of transient transfection and expression of foreign genes in neuronal cells. Not only should these interactions be considered in transient transfection studies of neurotrophin-deprived neurons, but also their elucidation could lead to novel methods for achieving neuroprotection.
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Affiliation(s)
- A L Schmehil
- Department of Ophthalmology and Visual Sciences and the Neuroscience Training Program, University of Wisconsin Medical School, 600 Highland Avenue, Madison, WI 53792-4673, USA
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16
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Haas MJ, Parseghian SA, Sajid RM, Mooradian AD. Effect of thyroid hormone responsive protein (THRP) expression on PC12 cell survival. Exp Brain Res 2003; 150:75-84. [PMID: 12698219 DOI: 10.1007/s00221-003-1406-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2002] [Accepted: 01/22/2003] [Indexed: 10/20/2022]
Abstract
The thyroid hormone responsive protein (THRP) is a novel gene product that remains responsive to thyroid hormone in the cerebral cortex of adult rats. The biological effects of THRP are currently unknown. Since thyroid hormones (TH) are known to cause cell death in primary neuronal cultures, the effect of exogenous THRP expression on PC12 cell viability was investigated. Co-transfection of the THRP expression plasmid with the selectable marker pSV2neo resulted in a lower number of surviving PC12 cells compared to transfection with pSV2neo and the empty vector, pSVL. Similar results were observed when PC12 cells were transfected with the plasmid pCMV. SPORT beta-gal with and without pSVL-THRP. However, expression of exogenous THRP in the colonic epithelial cell line Caco-2 and the glial cell line U251 had no effect on cell viability. Coexpression of THRP with either the wild-type (WT)-c-Abl or a kinase-defective mutant c-Abl (K290R) did not alter the cell viability changes induced by THRP alone. Under these experimental conditions the predominant form of cell death was necrosis as evidenced by in situ analyses, such as terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) and staining with membrane permeating and non-permeating nuclear dyes, Hoechst 33342 and propidium iodide respectively. In addition cell cycle arrest induced by THRP was demonstrated by reduced (3)H-thymidine incorporation into cellular DNA. The number of PC12 cells treated with 10(-7) M of l-3, 5, 3'-triiodothyronine (T(3)) was significantly reduced after the fourth day of culture. Treatment of the cells with T(3 )resulted in a dose dependent induction of THRP mRNA. It is concluded that: (1). THRP expression induces PC12 cell death; (2). under these experimental conditions the form of cell death is predominantly necrosis although cell cycle arrest may also occur; (3). the effect of THRP on cell viability is not modulated by c-Abl tyrosine kinase; and (4). the effect of T(3 )treatment on PC12 cell survival may be mediated by THRP.
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Affiliation(s)
- Michael J Haas
- Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO, USA
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17
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Abstract
Large-scale sources of neural stem cells are crucial for both basic research and novel approaches toward treating neurological disorders. Three sources that produce neural cells closely resembling their normal counterparts are now available: oncogene immortalized stem cells, neurospheres, and embryonic stem cell (ES)-derived neural cells. Cells including multiple subtypes of CNS and PNS neurons, as well as oligodendrocytes, Schwann cells, and astrocytes, are modeled by these large-scale sources. Although most cell lines were originally from rodents, their human counterparts are being discovered and characterized.
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Affiliation(s)
- David I Gottlieb
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri, USA.
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