1
|
Al-Hawary SIS, Pallathadka H, Hjazi A, Zhumanov ZE, Alazbjee AAA, Imad S, Alsalamy A, Hussien BM, Jaafer NS, Mahmoudi R. ETS transcription factor ELK3 in human cancers: An emerging therapeutic target. Pathol Res Pract 2023; 248:154728. [PMID: 37542863 DOI: 10.1016/j.prp.2023.154728] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 07/26/2023] [Accepted: 07/29/2023] [Indexed: 08/07/2023]
Abstract
Cancer is a genetic and complex disorder, resulting from several events associated with onset, development, and metastasis. Tumor suppressors and oncogenes are among the main regulators of tumor progression, contributing to various cancer-related behaviors like cell proliferation, invasion, migration, epithelial-mesenchymal transition (EMT), cell cycle, and apoptosis. Transcription factors (TFs) could act as tumor suppressors or oncogenes in cancer progression. E-twenty-six/E26 (ETS) family of TFs have a winged helix-turn-helix (HLH) motif, which interacted with specific DNA regions with high levels of purines and GGA core. ETS proteins act as transcriptional repressors or activators to modulate the expression of target genes. ETS transcription factor ELK3 (ELK3), as a type of ETS protein, was shown to enhance in various cancers, suggesting that it may have an oncogenic role. These studies indicated that ELK3 promoted invasion, migration, cell cycle, proliferation, and EMT, and suppressed cell apoptosis. In addition, these studies demonstrated that ELK3 could be a promising diagnostic and prognostic biomarker in human cancer. Moreover, accumulating data proved that ELK3 could be a novel chemoresistance mediator in human cancer. Here, we aimed to explore the overall change of ELK3 and its underlying molecular mechanism in human cancers. Moreover, we aimed to investigate the potential role of ELK3 as a prognostic and diagnostic biomarker as well as its capability as a chemoresistance mediator in cancer.
Collapse
Affiliation(s)
| | | | - Ahmed Hjazi
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
| | - Ziyadulla Eshmamatovich Zhumanov
- Department of Pathological Anatomy, With a Section-biopsy Course, Samarkand State Medical Institute, Amir Temur Street 18, Samarkand, Uzbekistan; Department of Scientific Affairs, Tashkent State Dental Institute, Makhtumkuli Street 103, Tashkent 100047, Uzbekistan
| | | | - Shad Imad
- Medical Technical College, Al-Farahidi University, Baghdad, Iraq
| | - Ali Alsalamy
- College of Technical Engineering, Imam Ja'afar Al-Sadiq University, Al-Muthanna 66002, Iraq
| | - Beneen M Hussien
- Medical Laboratory Technology Department, College of Medical Technology, The Islamic University, Najaf, Iraq
| | - Noor Sadiq Jaafer
- Department of Medical Laboratory Technologies, Al Rafidain University College, Bagdad, Iraq
| | - Reza Mahmoudi
- Department of Toxicology and Pharmacology, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
2
|
EGF-Dependent Activation of ELK1 Contributes to the Induction of CLDND1 Expression Involved in Tight Junction Formation. Biomedicines 2022; 10:biomedicines10081792. [PMID: 35892692 PMCID: PMC9329870 DOI: 10.3390/biomedicines10081792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/14/2022] [Accepted: 07/22/2022] [Indexed: 11/23/2022] Open
Abstract
Claudin proteins are intercellular adhesion molecules. Increased claudin domain-containing 1 (CLDND1) expression is associated with the malignant transformation of estrogen receptor-negative breast cancer cells with low sensitivity to hormone therapy. Abnormal CLDND1 expression is also implicated in vascular diseases. Previously, we investigated the regulatory mechanism underlying CLDND1 expression and identified a strong enhancer region near the promoter. In silico analysis of the sequence showed high homology to the ETS domain-containing protein-1 (ELK1)-binding sequence which is involved in cell growth, differentiation, angiogenesis, and cancer. Transcriptional ELK1 activation is associated with the mitogen-activated protein kinase (MAPK) signaling cascade originating from the epidermal growth factor receptor (EGFR). Here, we evaluated the effect of gefitinib, an EGFR tyrosine kinase inhibitor, on the suppression of CLDND1 expression using ELK1 overexpression in luciferase reporter and chromatin immunoprecipitation assays. ELK1 was found to be an activator of the enhancer region, and its transient expression increased that of CLDND1 at the mRNA and protein levels. CLDND1 expression was increased following EGF-induced ELK1 phosphorylation. Furthermore, this increase in CLDND1 was significantly suppressed by gefitinib. Therefore, EGF-dependent activation of ELK1 contributes to the induction of CLDND1 expression. These findings open avenues for the development of new anticancer agents targeting CLDND1.
Collapse
|
3
|
Gene Regulatory Network of ETS Domain Transcription Factors in Different Stages of Glioma. J Pers Med 2021; 11:jpm11020138. [PMID: 33671331 PMCID: PMC7922321 DOI: 10.3390/jpm11020138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/07/2021] [Accepted: 02/13/2021] [Indexed: 12/30/2022] Open
Abstract
The ETS domain family of transcription factors is involved in a number of biological processes, and is commonly misregulated in various forms of cancer. Using microarray datasets from patients with different grades of glioma, we have analyzed the expression profiles of various ETS genes, and have identified ETV1, ELK3, ETV4, ELF4, and ETV6 as novel biomarkers for the identification of different glioma grades. We have further analyzed the gene regulatory networks of ETS transcription factors and compared them to previous microarray studies, where Elk-1-VP16 or PEA3-VP16 were overexpressed in neuroblastoma cell lines, and we identify unique and common regulatory networks for these ETS proteins.
Collapse
|
4
|
Pardy L, Rosati R, Soave C, Huang Y, Kim S, Ratnam M. The ternary complex factor protein ELK1 is an independent prognosticator of disease recurrence in prostate cancer. Prostate 2020; 80:198-208. [PMID: 31794091 PMCID: PMC7302117 DOI: 10.1002/pros.23932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 11/18/2019] [Indexed: 01/28/2023]
Abstract
BACKGROUND Both hormone-sensitive and castration- and enzalutamide-resistant prostate cancers (PCa) depend on the ternary complex factor (TCF) protein ELK1 to serve as a tethering protein for the androgen receptor (AR) to activate a critical set of growth genes. The two sites in ELK1 required for AR binding are conserved in other members of the TCF subfamily, ELK3 and ELK4. Here we examine the potential utility of the three proteins as prognosticators of disease recurrence in PCa. METHODS Transcriptional activity assays; Retrospective analysis of PCa recurrence using data on 501 patients in The Cancer Genome Atlas (TCGA) database; Unpaired Wilcoxon rank-sum test and multiple comparison correction using the Holm's method; Spearman's correlations; Kaplan-Meier methods; Univariable and multivariable Cox regression analyses; LASSO-based penalized Cox regression models; Time-dependent area under the receiver operating characteristic (ROC) curve. RESULTS ELK4 but not ELK3 was coactivated by AR similar to ELK1. Tumor expression of neither ELK3 nor ELK4 was associated with disease-free survival (DFS). ELK1 was associated with higher clinical T-stage, pathology T-stage, Gleason score, prognostic grade, and positive lymph node status. ELK1 was a negative prognosticator of DFS, independent of ELK3, ELK4, clinical T-stage, pathology T-stage, prognostic grade, lymph node status, age, and race. Inclusion of ELK1 increased the abilities of the Oncotype DX and Prolaris gene panels to predict disease recurrence, correctly predicting disease recurrence in a unique subset of patients. CONCLUSIONS ELK1 is a strong, independent prognosticator of disease recurrence in PCa, underscoring its unique role in PCa growth. Inclusion of ELK1 may enhance the utility of currently used prognosticators for clinical decision making in prostate cancer.
Collapse
Affiliation(s)
- Luke Pardy
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Rayna Rosati
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Claire Soave
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Yanfang Huang
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Seongho Kim
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| | - Manohar Ratnam
- Department of Oncology and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan
| |
Collapse
|
5
|
Liu F, Liu Q, Yuan F, Guo S, Liu J, Sun Z, Gao P, Wang Y, Yan S, Liu J. Erg mediates downregulation of claudin-5 in the brain endothelium of a murine experimental model of cerebral malaria. FEBS Lett 2019; 593:2585-2595. [PMID: 31271645 DOI: 10.1002/1873-3468.13526] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 06/19/2019] [Accepted: 06/20/2019] [Indexed: 12/17/2022]
Abstract
Cerebral malaria (CM) is a severe complication with brain vascular hyperpermeability. Claudin-5 is the major component of tight junctions. To investigate the expression of claudin-5 in CM, we established a murine experimental cerebral malaria (ECM) model and an in vitro model by treating murine brain endothelial cells (bEnd3) with plasma from ECM mice. Expression of claudin-5 and the ETS transcription factor Erg was reduced in the brain endothelium of ECM mice. In bEnd3 cells exposed to ECM plasma, decreased expression of claudin-5 and Erg, and increased permeability were observed. Silencing of Erg significantly reduced Cldn5 expression. ChIP assays indicated that Erg binds to the -813 ETS motif of the murine Cldn5 gene promoter, and the binding is decreased by treatment with ECM plasma.
Collapse
Affiliation(s)
- Fuhong Liu
- Laboratory of Microvascular Medicine, Medical Research Center, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, China
| | - Qiang Liu
- Laboratory of Microvascular Medicine, Medical Research Center, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, China
| | - Fangshu Yuan
- Department of Human Parasitology, School of Medicine, Shandong University, Jinan, China
| | - Shuling Guo
- Department of Human Parasitology, School of Medicine, Shandong University, Jinan, China
| | - Jinzhi Liu
- Department of Neurology, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, China
| | - Zongguo Sun
- Laboratory of Microvascular Medicine, Medical Research Center, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, China
| | - Peng Gao
- Laboratory of Microvascular Medicine, Medical Research Center, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, China
| | - Yu Wang
- School of Medicine, Shandong University, Jinan, China
| | - Suhua Yan
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, China
| | - Ju Liu
- Laboratory of Microvascular Medicine, Medical Research Center, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, China
| |
Collapse
|
6
|
Adamo P, Porazinski S, Rajatileka S, Jumbe S, Hagen R, Cheung MK, Wilson I, Ladomery MR. The oncogenic transcription factor ERG represses the transcription of the tumour suppressor gene PTEN in prostate cancer cells. Oncol Lett 2017; 14:5605-5610. [PMID: 29113189 DOI: 10.3892/ol.2017.6841] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 08/03/2017] [Indexed: 11/05/2022] Open
Abstract
The oncogene ETS-related gene (ERG) encodes a transcription factor with roles in the regulation of haematopoiesis, angiogenesis, vasculogenesis, inflammation, migration and invasion. The ERG oncogene is activated in >50% of prostate cancer cases, generally through a gene fusion with the androgen-responsive promoter of transmembrane protease serine 2. Phosphatase and tensin homologue (PTEN) is an important tumour suppressor gene that is often inactivated in cancer. ERG overexpression combined with PTEN inactivation or loss is often associated with aggressive prostate cancer. The present study aimed to determine whether or not ERG regulates PTEN transcription directly. ERG was demonstrated to bind to the PTEN promoter and repress its transcription. ERG overexpression reduced endogenous PTEN expression, whereas ERG knockdown increased PTEN expression. The ability of ERG to repress PTEN may contribute to a more cancer-permissive environment.
Collapse
Affiliation(s)
- Patricia Adamo
- Faculty of Health and Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Sean Porazinski
- Faculty of Health and Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Shavanthi Rajatileka
- Faculty of Health and Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Samantha Jumbe
- Faculty of Health and Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Rachel Hagen
- Faculty of Health and Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Man-Kim Cheung
- Faculty of Health and Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Ian Wilson
- Faculty of Health and Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Michael R Ladomery
- Faculty of Health and Applied Sciences, University of the West of England, Bristol BS16 1QY, UK
| |
Collapse
|
7
|
Panagoulias I, Georgakopoulos T, Aggeletopoulou I, Agelopoulos M, Thanos D, Mouzaki A. Transcription Factor Ets-2 Acts as a Preinduction Repressor of Interleukin-2 (IL-2) Transcription in Naive T Helper Lymphocytes. J Biol Chem 2016; 291:26707-26721. [PMID: 27815505 DOI: 10.1074/jbc.m116.762179] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/01/2016] [Indexed: 11/06/2022] Open
Abstract
IL-2 is the first cytokine produced when naive T helper (Th) cells are activated and differentiate into dividing pre-Th0 proliferating precursors. IL-2 expression is blocked in naive, but not activated or memory, Th cells by the transcription factor Ets-2 that binds to the antigen receptor response element (ARRE)-2 of the proximal IL-2 promoter. Ets-2 acts as an independent preinduction repressor in naive Th cells and does not interact physically with the transcription factor NFAT (nuclear factor of activated T-cells) that binds to the ARRE-2 in activated Th cells. In naive Th cells, Ets-2 mRNA expression, Ets-2 protein levels, and Ets-2 binding to ARRE-2 decrease upon cell activation followed by the concomitant expression of IL-2. Cyclosporine A stabilizes Ets-2 mRNA and protein when the cells are activated. Ets-2 silences directly constitutive or induced IL-2 expression through the ARRE-2. Conversely, Ets-2 silencing allows for constitutive IL-2 expression in unstimulated cells. Ets-2 binding to ARRE-2 in chromatin is stronger in naive compared with activated or memory Th cells; in the latter, Ets-2 participates in a change of the IL-2 promoter architecture, possibly to facilitate a quick response when the cells re-encounter antigen. We propose that Ets-2 expression and protein binding to the ARRE-2 of the IL-2 promoter are part of a strictly regulated process that results in a physiological transition of naive Th cells to Th0 cells upon antigenic stimulation. Malfunction of such a repression mechanism at the molecular level could lead to a disturbance of later events in Th cell plasticity, leading to autoimmune diseases or other pathological conditions.
Collapse
Affiliation(s)
- Ioannis Panagoulias
- From the Division of Hematology, Department of Internal Medicine, Faculty of Medicine, University of Patras, Patras GR-26500, Greece and
| | - Tassos Georgakopoulos
- From the Division of Hematology, Department of Internal Medicine, Faculty of Medicine, University of Patras, Patras GR-26500, Greece and
| | - Ioanna Aggeletopoulou
- From the Division of Hematology, Department of Internal Medicine, Faculty of Medicine, University of Patras, Patras GR-26500, Greece and
| | - Marios Agelopoulos
- the Institute of Molecular Biology, Genetics and Biotechnology, Biomedical Research Foundation, Academy of Athens, Athens GR-11527, Greece
| | - Dimitris Thanos
- the Institute of Molecular Biology, Genetics and Biotechnology, Biomedical Research Foundation, Academy of Athens, Athens GR-11527, Greece
| | - Athanasia Mouzaki
- From the Division of Hematology, Department of Internal Medicine, Faculty of Medicine, University of Patras, Patras GR-26500, Greece and
| |
Collapse
|
8
|
The oncogene ERG: a key factor in prostate cancer. Oncogene 2015; 35:403-14. [PMID: 25915839 DOI: 10.1038/onc.2015.109] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/05/2015] [Accepted: 03/06/2015] [Indexed: 12/20/2022]
Abstract
ETS-related gene (ERG) is a member of the E-26 transformation-specific (ETS) family of transcription factors with roles in development that include vasculogenesis, angiogenesis, haematopoiesis and bone development. ERG's oncogenic potential is well known because of its involvement in Ewing's sarcoma and leukaemia. However, in the past decade ERG has become highly associated with prostate cancer development, particularly as a result of a gene fusion with the promoter region of the androgen-induced TMPRRSS2 gene. We review ERG's structure and function, and its role in prostate cancer. We discuss potential new therapies that are based on targeting ERG.
Collapse
|
9
|
Chen L, Feng L, Wang X, Du J, Chen Y, Yang W, Zhou C, Cheng L, Shen Y, Fang S, Li J, Shen Y. Mesencephalic astrocyte-derived neurotrophic factor is involved in inflammation by negatively regulating the NF-κB pathway. Sci Rep 2015; 5:8133. [PMID: 25640174 PMCID: PMC4313098 DOI: 10.1038/srep08133] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/08/2015] [Indexed: 12/12/2022] Open
Abstract
Inflammation can cause endoplasmic reticulum (ER) stress and therefore activates the unfolded protein response (UPR). ER stress and the consequent UPR have the potential to activate NF-κB. However, the factors mediating the crosstalk between ER stress and the NF-κB pathway remain unclear. Here, we determined that ER stress inducible protein Mesencephalic Astrocyte-derived Neurotrophic Factor (MANF) was up-regulated in autoimmune diseases and inflammatory disease models. Inflammation caused MANF to relocalize to the nuclei. MANF interacted with the DNA binding domain of p65 through its C-terminal SAP-like domain in the nuclei under the condition of inflammation or ER stress. MANF consequently inhibited p65-mediated transcriptional activation by interfering with the binding of p65 to its target genes promoters. Consistently, MANF suppressed the expressions of NF-κB-dependent target genes and the proliferation of inflammatory synoviocytes. These findings suggest that MANF may be a negative regulator of inflammation and mediate the crosstalk between the NF-κB pathway and ER stress.
Collapse
Affiliation(s)
- Lijian Chen
- 1] School of Pharmacy, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China [3] Department of Anesthesiology of the First Affiliated Hospital, Anhui Medical University, Hefei 230022, Anhui, China
| | - Lijie Feng
- 1] School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China
| | - Xia Wang
- 1] School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China
| | - Jian Du
- 1] School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China
| | - Ying Chen
- Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China
| | - Wen Yang
- 1] School of Pharmacy, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China
| | - Chengyue Zhou
- 1] School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China
| | - Li Cheng
- 1] School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China
| | - Yujun Shen
- 1] School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China
| | - Shengyun Fang
- 1] School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China [3] Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, MD 21201, USA
| | - Jun Li
- School of Pharmacy, Anhui Medical University, Hefei 230032, Anhui, China
| | - Yuxian Shen
- 1] School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, Anhui, China [2] Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, Anhui, China
| |
Collapse
|
10
|
Diverse ETS transcription factors mediate FGF signaling in the Ciona anterior neural plate. Dev Biol 2015; 399:218-25. [PMID: 25576927 DOI: 10.1016/j.ydbio.2014.12.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/23/2014] [Accepted: 12/24/2014] [Indexed: 11/24/2022]
Abstract
The ascidian Ciona intestinalis is a marine invertebrate belonging to the sister group of the vertebrates, the tunicates. Its compact genome and simple, experimentally tractable embryos make Ciona well-suited for the study of cell-fate specification in chordates. Tunicate larvae possess a characteristic chordate body plan, and many developmental pathways are conserved between tunicates and vertebrates. Previous studies have shown that FGF signals are essential for neural induction and patterning at sequential steps of Ciona embryogenesis. Here we show that two different ETS family transcription factors, Ets1/2 and Elk1/3/4, have partially redundant activities in the anterior neural plate of gastrulating embryos. Whereas Ets1/2 promotes pigment cell formation in lateral lineages, both Ets1/2 and Elk1/3/4 are involved in the activation of Myt1L in medial lineages and the restriction of Six3/6 expression to the anterior-most regions of the neural tube. We also provide evidence that photoreceptor cells arise from posterior regions of the presumptive sensory vesicle, and do not depend on FGF signaling. Cells previously identified as photoreceptor progenitors instead form ependymal cells and neurons of the larval brain. Our results extend recent findings on FGF-dependent patterning of anterior-posterior compartments in the Ciona central nervous system.
Collapse
|
11
|
Kar A, Gutierrez-Hartmann A. Molecular mechanisms of ETS transcription factor-mediated tumorigenesis. Crit Rev Biochem Mol Biol 2013; 48:522-43. [PMID: 24066765 DOI: 10.3109/10409238.2013.838202] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The E26 transformation-specific (ETS) family of transcription factors is critical for development, differentiation, proliferation and also has a role in apoptosis and tissue remodeling. Changes in expression of ETS proteins therefore have a significant impact on normal physiology of the cell. Transcriptional consequences of ETS protein deregulation by overexpression, gene fusion, and modulation by RAS/MAPK signaling are linked to alterations in normal cell functions, and lead to unlimited increased proliferation, sustained angiogenesis, invasion and metastasis. Existing data show that ETS proteins control pathways in epithelial cells as well as stromal compartments, and the crosstalk between the two is essential for normal development and cancer. In this review, we have focused on ETS factors with a known contribution in cancer development. Instead of focusing on a prototype, we address cancer associated ETS proteins and have highlighted the diverse mechanisms by which they affect carcinogenesis. Finally, we discuss strategies for ETS factor targeting as a potential means for cancer therapeutics.
Collapse
|
12
|
Patki M, Chari V, Sivakumaran S, Gonit M, Trumbly R, Ratnam M. The ETS domain transcription factor ELK1 directs a critical component of growth signaling by the androgen receptor in prostate cancer cells. J Biol Chem 2013; 288:11047-65. [PMID: 23426362 DOI: 10.1074/jbc.m112.438473] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The androgen receptor (AR) is essential for diverse aspects of prostate development and function. Molecular mechanisms by which prostate cancer (PC) cells redirect AR signaling to genes that primarily support growth are unclear. A systematic search for critical AR-tethering proteins led to ELK1, an ETS transcription factor of the ternary complex factor subfamily. Although genetically redundant, ELK1 was obligatory for AR-dependent growth and clonogenic survival in both hormone-dependent PC and castration-recurrent PC cells but not for AR-negative cell growth. AR required ELK1 to up-regulate a major subset of its target genes that was strongly and primarily enriched for cell growth functions. AR functioned as a coactivator of ELK1 by association through its A/B domain, bypassing the classical mechanism of ELK1 activation by phosphorylation and without inducing ternary complex target genes. The ELK1-AR synergy per se was ligand-independent, although it required ligand for nuclear localization of AR as targeting the AR A/B domain to the nucleus recapitulated the action of hormone; accordingly, Casodex was a poor antagonist of the synergy. ELK3, the closest substitute for ELK1 in structure/function and genome recognition, did not interact with AR. ELK1 thus directs selective and sustained gene induction that is a substantial and critical component of growth signaling by AR in PC cells. The ELK1-AR interaction offers a functionally tumor-selective drug target.
Collapse
Affiliation(s)
- Mugdha Patki
- Barbara Ann Karmanos Cancer Institute, Detroit, Michigan 48201-2013, USA
| | | | | | | | | | | |
Collapse
|
13
|
Hussain A, Shaw PE, Hirst JD. Molecular dynamics simulations and in silico peptide ligand screening of the Elk-1 ETS domain. J Cheminform 2011; 3:49. [PMID: 22044511 PMCID: PMC3227621 DOI: 10.1186/1758-2946-3-49] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 11/01/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Elk-1 transcription factor is a member of a group of proteins called ternary complex factors, which serve as a paradigm for gene regulation in response to extracellular signals. Its deregulation has been linked to multiple human diseases including the development of tumours. The work herein aims to inform the design of potential peptidomimetic compounds that can inhibit the formation of the Elk-1 dimer, which is key to Elk-1 stability. We have conducted molecular dynamics simulations of the Elk-1 ETS domain followed by virtual screening. RESULTS We show the ETS dimerisation site undergoes conformational reorganisation at the α1β1 loop. Through exhaustive screening of di- and tri-peptide libraries against a collection of ETS domain conformations representing the dynamics of the loop, we identified a series of potential binders for the Elk-1 dimer interface. The di-peptides showed no particular preference toward the binding site; however, the tri-peptides made specific interactions with residues: Glu17, Gln18 and Arg49 that are pivotal to the dimer interface. CONCLUSIONS We have shown molecular dynamics simulations can be combined with virtual peptide screening to obtain an exhaustive docking protocol that incorporates dynamic fluctuations in a receptor. Based on our findings, we suggest experimental binding studies to be performed on the 12 SILE ranked tri-peptides as possible compounds for the design of inhibitors of Elk-1 dimerisation. It would also be reasonable to consider the score-ranked tri-peptides as a comparative test to establish whether peptide size is a determinant factor of binding to the ETS domain.
Collapse
Affiliation(s)
- Abrar Hussain
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Peter E Shaw
- School of Biomedical Sciences, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Jonathan D Hirst
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| |
Collapse
|
14
|
Demir O, Aysit N, Onder Z, Turkel N, Ozturk G, Sharrocks AD, Kurnaz IA. ETS-domain transcription factor Elk-1 mediates neuronal survival: SMN as a potential target. Biochim Biophys Acta Mol Basis Dis 2011; 1812:652-62. [PMID: 21362474 DOI: 10.1016/j.bbadis.2011.02.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 02/11/2011] [Accepted: 02/23/2011] [Indexed: 11/16/2022]
Abstract
Elk-1 belongs to the ternary complex factors (TCFs) subfamily of the ETS domain proteins, and plays a critical role in the expression of immediate-early genes (IEGs) upon mitogen stimulation and activation of the mitogen-activated protein kinase (MAPK) cascade. The association of TCFs with serum response elements (SREs) on IEG promoters has been widely studied and a role for Elk-1 in promoting cell cycle entry has been determined. However, the presence of the ETS domain transcription factor Elk-1 in axons and dendrites of post-mitotic adult brain neurons has implications for an alternative function for Elk-1 in neurons other than controlling proliferation. In this study, possible alternative roles for Elk-1 in neurons were investigated, and it was demonstrated that blocking TCF-mediated transactivation in neuronal cells leads to apoptosis through a caspase-dependent mechanism. Indeed RNAi-mediated depletion of endogenous Elk-1 results in increased caspase activity. Conversely, overexpression of either Elk-1 or Elk-VP16 fusion proteins was shown to rescue PC12 cells from chemically-induced apoptosis, and that higher levels of endogenous Elk-1 correlated with longer survival of DRGs in culture. It was shown that Elk-1 regulated the Mcl-1 gene expression required for survival, and that RNAi-mediated degradation of endogenous Elk-1 resulted in elimination of the mcl-1 message. We have further identified the survival-of-motor neuron-1 (SMN1) gene as a novel target of Elk-1, and show that the ets motifs in the SMN1 promoter are involved in this regulation.
Collapse
Affiliation(s)
- Ozlem Demir
- Yeditepe University, Department of Genetics and Bioengineering, 26 Agustos Yerlesimi, 34755, Kayisdagi, Istanbul, Turkey
| | | | | | | | | | | | | |
Collapse
|
15
|
Severyn CJ, Rotwein P. Conserved proximal promoter elements control repulsive guidance molecule c/hemojuvelin (Hfe2) gene transcription in skeletal muscle. Genomics 2010; 96:342-51. [PMID: 20858542 PMCID: PMC2988867 DOI: 10.1016/j.ygeno.2010.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Revised: 09/06/2010] [Accepted: 09/15/2010] [Indexed: 01/18/2023]
Abstract
Repulsive guidance molecule c (RGMc; gene symbol: Hfe2) plays a critical role in iron metabolism. Inactivating mutations cause juvenile hemochromatosis, a severe iron overload disorder. Understanding mechanisms controlling RGMc biosynthesis has been hampered by minimal information about the RGMc gene. Here we define the structure, examine the evolution, and establish mechanisms of regulation of the mouse RGMc gene. RGMc is a 4-exon gene that undergoes alternative RNA splicing to yield 3 mRNAs with 5' different untranslated regions. Gene transcription is induced during myoblast differentiation, producing all 3 mRNAs. We identify 3 critical promoter elements responsible for transcriptional activation in skeletal muscle, comprising paired E-boxes, a putative Stat and/or Ets element, and a MEF2 site, and muscle transcription factors myogenin and MEF2C stimulate RGMc promoter function in non-muscle cells. As these elements are conserved in RGMc genes from multiple species, our results suggest that RGMc has been a muscle-enriched gene throughout its evolutionary history.
Collapse
Affiliation(s)
- Christopher J. Severyn
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239-3098, U.S.A
| | - Peter Rotwein
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239-3098, U.S.A
| |
Collapse
|
16
|
Costello P, Nicolas R, Willoughby J, Wasylyk B, Nordheim A, Treisman R. Ternary Complex Factors SAP-1 and Elk-1, but Not Net, Are Functionally Equivalent in Thymocyte Development. THE JOURNAL OF IMMUNOLOGY 2010; 185:1082-92. [DOI: 10.4049/jimmunol.1000472] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
17
|
Genome-wide analysis of ETS-family DNA-binding in vitro and in vivo. EMBO J 2010; 29:2147-60. [PMID: 20517297 PMCID: PMC2905244 DOI: 10.1038/emboj.2010.106] [Citation(s) in RCA: 423] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Accepted: 05/04/2010] [Indexed: 12/30/2022] Open
Abstract
Members of the large ETS family of transcription factors (TFs) have highly similar DNA-binding domains (DBDs)—yet they have diverse functions and activities in physiology and oncogenesis. Some differences in DNA-binding preferences within this family have been described, but they have not been analysed systematically, and their contributions to targeting remain largely uncharacterized. We report here the DNA-binding profiles for all human and mouse ETS factors, which we generated using two different methods: a high-throughput microwell-based TF DNA-binding specificity assay, and protein-binding microarrays (PBMs). Both approaches reveal that the ETS-binding profiles cluster into four distinct classes, and that all ETS factors linked to cancer, ERG, ETV1, ETV4 and FLI1, fall into just one of these classes. We identify amino-acid residues that are critical for the differences in specificity between all the classes, and confirm the specificities in vivo using chromatin immunoprecipitation followed by sequencing (ChIP-seq) for a member of each class. The results indicate that even relatively small differences in in vitro binding specificity of a TF contribute to site selectivity in vivo.
Collapse
|
18
|
Lee SM, Vasishtha M, Prywes R. Activation and repression of cellular immediate early genes by serum response factor cofactors. J Biol Chem 2010; 285:22036-49. [PMID: 20466732 DOI: 10.1074/jbc.m110.108878] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The induction of expression of many cellular immediate early genes (IEG) involves the transcription factor serum response factor (SRF). Two families of SRF coactivators have also been implicated in IEG induction, the ternary complex factors (TCFs), ELK1, Sap1, and Net, and the myocardin-related factors, MKL1 and MKL2. We found that serum induction of some SRF target genes is preferentially regulated by MKL1/2, whereas others are redundantly activated by both TCFs and MKL1/2. Yet ELK1 can also repress transcription. Binding of ELK1 and MKL1 to SRF has been found to be mutually exclusive in vitro, suggesting that ELK1 could repress expression of IEGs by blocking MKL1 binding. We characterized the in vivo binding of MKL1 and ELK1 to target genes and found an inverse relationship of serum-induced MKL1 binding and serum-decreased ELK1 binding. However, experiments with short hairpin RNA-mediated MKL1/2 depletion and expression of a nuclear MKL1 (N100) variant in stably transfected cells failed to alter ELK1 binding, suggesting that ELK1 binding to target genes is regulated independently of MKL1/2. Nevertheless, we found that short interfering RNA-mediated depletion of TCFs increased target gene expression in cells containing the N100 MKL1 activator, most notably in cells under continuous growth conditions. These results indicate that the TCFs can function both as activators and repressors of target gene expression depending upon the cellular growth conditions.
Collapse
Affiliation(s)
- Seung-Min Lee
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | | | | |
Collapse
|
19
|
Wang Z, Zhang Q. Genome-wide identification and evolutionary analysis of the animal specific ETS transcription factor family. Evol Bioinform Online 2009; 5:119-31. [PMID: 20011068 PMCID: PMC2789578 DOI: 10.4137/ebo.s2948] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The ETS proteins are a family of transcription factors (TFs) that regulate a variety of biological processes. We made genome-wide analyses to explore the classification of the ETS gene family. We identified 207 ETS genes which encode 321 ETS TFs from ten animal species. Of the 321 ETS TFs, 155 contain only an ETS domain, about 50% contain a ETS_PEA3_N or a SAM_PNT domain in addition to an ETS domain, the rest (only four) contain a second ETS domain or a second ETS_PEA3_N domain or an another domain (AT_hook or DNA_pol_B). A Neighbor-Joining phylogenetic tree was constructed using the amino acid sequences of the ETS domain of the ETS TFs. The results revealed that the ETS genes of the ten species can be divided into two distinct groups. Group I contains one nematode ETS gene and 18 vertebrate animal ETS genes. Group II contains the majority of the ETS TFs and can be further divided into eleven subgroups. The sequence motifs outside the DNA-binding domain and the conservation of the exon-intron structural patterns of the ETS TFs in human, cattle, and chicken further support the phylogenetic classification among these ETS TFs. Extensive duplication of the ETS genes was found in the genome of each species. The duplicated ETS genes account for ~69% of the total of ETS genes. Furthermore, we also found there are ETS gene clusters in all of the ten animal species. Statistical analysis of the Gene Ontology annotations of the ETS genes showed that the ETS proteins tend to be related to RNA biosynthetic process, biopolymer metabolic process and macromolecule metabolic process expected from the common GO categories of transcriptional factors. We also discussed the functional conservation and diversification of ETS TFs.
Collapse
Affiliation(s)
- Zhipeng Wang
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | | |
Collapse
|
20
|
Winter HY, Dayaram T, Marriott SJ. Activation of the human T-cell leukemia virus type 1 long terminal repeat by the ternary complex factor Elk-1. J Virol 2007; 81:13075-81. [PMID: 17898074 PMCID: PMC2169132 DOI: 10.1128/jvi.00968-07] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Serum response factor (SRF) was recently shown to bind and activate the human T-cell leukemia virus type 1 (HTLV-1) promoter at bases -116 to -125 relative to the transcription start site. In addition to the SRF binding site (CArG box), serum response elements (SRE) also typically contain a binding site for a member of the ternary complex factor (TCF) family. Here we demonstrate the presence of two TCF binding sites upstream of the viral CArG box. Binding of the TCF family member Elk-1 to these sites was shown to activate transcription of the promoter. Based on these results, the position of the previously described viral SRE (vSRE) within the HTLV-1 promoter can be extended from -116 to -157 to include the two newly identified TCF sites. Purified Elk-1 bound to a probe containing the vSRE, and this complex formed a ternary complex with SRF. In addition, the complex formed by nuclear extract on this probe contained Elk-1, as shown by electrophoretic mobility shift assay supershift. Both of the predicted TCF sites independently bound Elk-1. Elk-1 activated transcription of the HTLV-1 long terminal repeat (LTR), and mutations within either of the TCF sites or the CArG box reduced responsiveness of the LTR to Elk-1. Chromatin immunoprecipitation demonstrated that Elk-1 associates with the HTLV-1 LTR in vivo. These results identify a functional SRE within the HTLV-1 LTR and suggest that both Elk-1 and SRF play important roles in regulating basal HTLV-1 gene expression.
Collapse
Affiliation(s)
- Heather Y Winter
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, MS-385, One Baylor Plaza, Houston, Texas 77030, USA
| | | | | |
Collapse
|
21
|
Abstract
The association of transcriptional coactivators with DNA-binding proteins provides an efficient mechanism to expand and modulate genetic information encoded within the genome. Myocardin-related transcription factors (MRTFs), including myocardin, MRTF-A/MKL1/MAL, and MRTF-B/MKL2, comprise a family of related transcriptional coactivators that physically associate with the MADS box transcription factor, serum response factor, and synergistically activate transcription. MRTFs transduce cytoskeletal signals to the nucleus, activating a subset of serum response factor-dependent genes promoting myogenic differentiation and cytoskeletal organization. MRTFs are multifunctional proteins that share evolutionarily conserved domains required for actin-binding, homo- and heterodimerization, high-order chromatin organization, and transcriptional activation. Mice harboring loss-of-function mutations in myocardin, MRTF-A, and MRTF-B, respectively, display distinct phenotypes, including cell autonomous defects in vascular smooth muscle cell and myoepithelial cell differentiation and function. This article reviews the molecular basis of MRTF function with particular focus on the role MRTFs play in regulating cardiovascular patterning, vascular smooth muscle cell and cardiomyocyte differentiation and in the pathogenesis of congenital heart disease and vascular proliferative syndromes.
Collapse
Affiliation(s)
- Michael S Parmacek
- University of Pennsylvania Cardiovascular Institute and Department of Medicine, University of Pennsylvania, Philadelphia, USA.
| |
Collapse
|
22
|
Chumakov AM, Silla A, Williamson EA, Koeffler HP. Modulation of DNA binding properties of CCAAT/enhancer binding protein epsilon by heterodimer formation and interactions with NFkappaB pathway. Blood 2007; 109:4209-19. [PMID: 17255362 PMCID: PMC1885488 DOI: 10.1182/blood-2005-09-031963] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
C/EBP epsilon is a transcription factor involved in myeloid cell differentiation. Along with C/EBP-alpha, -beta, -gamma, -delta, and -zeta, C/EBP-epsilon belongs to the family of CCAAT/enhancer binding proteins that are implicated in control of growth and differentiation of several cell lineages in inflammation and stress response. We have previously shown that C/EBP-epsilon preferentially binds DNA as a heterodimer with other C/EBP family members such as C/EBP-delta, CHOP (C/EBP-zeta), and the b-zip family protein ATF4. In this study, we define the consensus binding sites for C/EBP-epsilon dimers and C/EBP-epsilon-ATF4 heterodimers. We show that the activated NFkappaB pathway promotes interaction of the C/EBP-epsilon subunit with its cognate DNA binding site via interaction with RelA. RelA-C/EBP interaction is enhanced by phosphorylation of threonine at amino acid 75 and results in increased DNA binding compared with the wild-type nonphosphorylated C/EBP both in vitro and in vivo. We suggest that interaction of the activated NFkappaB pathway and C/EBP-epsilon may be important in selective activation of a subset of C/EBP-epsilon-responsive genes.
Collapse
Affiliation(s)
- Alexey M Chumakov
- Department of Medicine, Cedars-Sinai Medical Center, University of California at Los Angeles, CA 90048, USA.
| | | | | | | |
Collapse
|
23
|
Ahn J, Ko M, Lee K, Oh J, Jeon SH, Seong RH. Expression of SRG3, a core component of mouse SWI/SNF chromatin-remodeling complex, is regulated by cooperative interactions between Sp1/Sp3 and Ets transcription factors. Biochem Biophys Res Commun 2005; 338:1435-46. [PMID: 16288722 DOI: 10.1016/j.bbrc.2005.10.107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 10/19/2005] [Indexed: 11/16/2022]
Abstract
SRG3, a mouse homolog of yeast SWI3 and human BAF155, is known to be a core component of SWI/SNF chromatin-remodeling complex. We have previously shown that SRG3 plays essential roles in early mouse embryogenesis, brain development, and T-cell development. SRG3 gene expression was differentially regulated depending on the developmental stages and exhibited tissue-specific pattern. In this study, we showed that the functional interactions between Sp and Ets family transcription factors are crucial for the SRG3 expression. Sp1 and Sp3 specifically bound to the two canonical Sp-binding sites (GC boxes) at -152 and -114, and a non-canonical Sp-binding site (CCTCCT motif) at -108 in the SRG3 promoter. Using Drosophila SL2 cells, we found that various Sp or Ets family members activate the SRG3 promoter through these Sp- or Ets-binding sites, respectively, in a dose-dependent manner. Intriguingly, different combinatorial expression of Ets and Sp factors in SL2 cells resulted in either strong synergistic activation or repression of the SRG3 promoter activity. Moreover, the Sp-mediated activation of SRG3 promoter required the intact Ets-binding element. Taken together, these results suggest that diverse interactions between Sp1/Sp3 and Ets factors are crucial for the SRG3 gene expression.
Collapse
Affiliation(s)
- Jeongeun Ahn
- Department of Biological Sciences, Institute of Molecular Biology and Genetics, Research Center for Functional Cellomics, Seoul National University, Seoul 151-742, Republic of Korea
| | | | | | | | | | | |
Collapse
|
24
|
Keeley MB, Busch J, Singh R, Abel T. TetR hybrid transcription factors report cell signaling and are inhibited by doxycycline. Biotechniques 2005; 39:529-36. [PMID: 16235565 DOI: 10.2144/000112002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We developed a bigenic reporter system composed of a hybrid transcription factor that combines the regulatory and activation domains of either Elk-1 or cyclic AMP-responsive element binding protein (CREB) with the DNA binding, dimerization, and regulatory domains from a synthetic variant of the bacterial Tet repressor (TetR). The novel hybrid transcription factor TetR-Elk-1 was regulated by MAPK ERK kinase 1 (MEK-1) overexpression, and TetR-CREB was regulated by protein kinase A (PKA) overexpression or elevation of cyclic AMP levels. These hybrid transcription factors could be useful reporters of cell signaling pathways because, unlike previous GAL4 hybrid reporters, TetR hybrid transcription factors are inhibited by the administration of doxycycline. We validated this system in cell culture transfection experiments utilizing luciferase assays to monitor reporter gene expression and Western blot analysis to monitor transcription factor expression and phosphorylation levels. This system may be useful in creating temporally restricted windows of response to cell signaling and may be of value in the advancement of methods used to study signal transduction.
Collapse
|
25
|
Williamson EA, Williamson IK, Chumakov AM, Friedman AD, Koeffler HP. CCAAT/enhancer binding protein epsilon: changes in function upon phosphorylation by p38 MAP kinase. Blood 2005; 105:3841-7. [PMID: 15677566 PMCID: PMC1895069 DOI: 10.1182/blood-2004-09-3708] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2004] [Accepted: 01/01/2005] [Indexed: 11/20/2022] Open
Abstract
C/EBPepsilon, a member of the CCAAT/enhancer binding protein family, is a transcription factor important in neutrophil differentiation. We have determined that it is phosphorylated on multiple serine and threonine residues and can be a target for phosphorylation by a number of kinases. We identified a threonine at amino acid 75, part of a consensus mitogen-activated protein (MAP) kinase site within the transactivation domain of C/EBPepsilon, as being phosphorylated only by p38 MAP kinase. Phosphorylation of this residue resulted in enhanced transcriptional activity on a myeloid-specific promoter in in vitro transient transfection reporter assays. We also determined that phosphorylation at Thr75 yielded a protein that was more effective at binding its cognate DNA sequence compared with the wild-type nonphosphorylated C/EBPepsilon. Stable expression of C/EBPepsilonT75A in interleukin 3 (IL-3)-dependent 32Dcl3 did not result in the up-regulation of expression of secondary granule genes compared with wild-type C/EBPepsilon or C/EBPepsilonT75D. Therefore we suggest that C/EBPepsilon is a target for p38 MAP kinase activity.
Collapse
Affiliation(s)
- Elizabeth A Williamson
- Department of Medicine, Hematology/Oncology, Cedars-Sinai Medical Center, University of California-Los Angeles, USA.
| | | | | | | | | |
Collapse
|
26
|
Park S, Boder ET, Saven JG. Modulating the DNA Affinity of Elk-1 with Computationally Selected Mutations. J Mol Biol 2005; 348:75-83. [PMID: 15808854 DOI: 10.1016/j.jmb.2004.12.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2004] [Revised: 12/13/2004] [Accepted: 12/16/2004] [Indexed: 10/25/2022]
Abstract
In order to regulate gene expression, transcription factors must first bind their target DNA sequences. The affinity of this binding is determined by both the network of interactions at the interface and the entropy change associated with the complex formation. To study the role of structural fluctuation in fine-tuning DNA affinity, we performed molecular dynamics simulations of two highly homologous proteins, Elk-1 and SAP-1, that exhibit different sequence specificity. Simulation studies show that several residues in Elk have significantly higher main-chain root-mean-square deviations than their counterparts in SAP. In particular, a single residue, D69, may contribute to Elk's lower DNA affinity for P(c-fos) by structurally destabilizing the carboxy terminus of the recognition helix. While D69 does not contact DNA directly, the increased mobility in the region may contribute to its weaker binding. We measured the ability of single point mutants of Elk to bind P(c-fos) in a reporter assay, in which D69 of wild-type Elk has been mutated to other residues with higher helix propensity in order to stabilize the local conformation. The gains in transcriptional activity and the free energy of binding suggested from these measurements correlate well with stability gains computed from helix propensity and charge-macrodipole interactions. The study suggests that residues that are distal to the binding interface may indirectly modulate the binding affinity by stabilizing the protein scaffold required for efficient DNA interaction.
Collapse
Affiliation(s)
- Sheldon Park
- Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | | | | |
Collapse
|
27
|
Miley GR, Fantz D, Glossip D, Lu X, Saito RM, Palmer RE, Inoue T, Van Den Heuvel S, Sternberg PW, Kornfeld K. Identification of residues of the Caenorhabditis elegans LIN-1 ETS domain that are necessary for DNA binding and regulation of vulval cell fates. Genetics 2005; 167:1697-709. [PMID: 15342509 PMCID: PMC1471005 DOI: 10.1534/genetics.104.029017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
LIN-1 is an ETS domain protein. A receptor tyrosine kinase/Ras/mitogen-activated protein kinase signaling pathway regulates LIN-1 in the P6.p cell to induce the primary vulval cell fate during Caenorhabditis elegans development. We identified 23 lin-1 loss-of-function mutations by conducting several genetic screens. We characterized the molecular lesions in these lin-1 alleles and in several previously identified lin-1 alleles. Nine missense mutations and 10 nonsense mutations were identified. All of these lin-1 missense mutations affect highly conserved residues in the ETS domain. These missense mutations can be arranged in an allelic series; the strongest mutations eliminate most or all lin-1 functions, and the weakest mutation partially reduces lin-1 function. An electrophoretic mobility shift assay was used to demonstrate that purified LIN-1 protein has sequence-specific DNA-binding activity that required the core sequence GGAA. LIN-1 mutant proteins containing the missense substitutions had dramatically reduced DNA binding. These experiments identify eight highly conserved residues of the ETS domain that are necessary for DNA binding. The identification of multiple mutations that reduce the function of lin-1 as an inhibitor of the primary vulval cell fate and also reduce DNA binding suggest that DNA binding is essential for LIN-1 function in an animal.
Collapse
Affiliation(s)
- Ginger R Miley
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Argyropoulos C, Nikiforidis GC, Theodoropoulou M, Adamopoulos P, Boubali S, Georgakopoulos TN, Paliogianni F, Papavassiliou AG, Mouzaki A. Mining microarray data to identify transcription factors expressed in naïve resting but not activated T lymphocytes. Genes Immun 2004; 5:16-25. [PMID: 14735145 DOI: 10.1038/sj.gene.6364034] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transcriptional repressors controlling the expression of cytokine genes have been implicated in a variety of physiological and pathological phenomena. An unknown repressor that binds to the distal NFAT element of the interleukin-2 (IL-2) gene promoter in naive T-helper lymphocytes has been implicated in autoimmune phenomena and has emerged as a potentially important factor controlling the latency of HIV-1. The aim of this paper was the identification of this repressor. We resorted to public microarray databases looking for DNA-binding proteins that are present in naïve resting T cells but are downregulated when the cells are activated. A Bayesian data mining statistical analysis uncovered 25 candidate factors. Of the 25, NFAT4 and the oncogene ets-2 bind to the common motif AAGGAG found in the HIV-1 LTR and IL-2 probes. Ets-2 binding site contains the three G's that have been shown to be important for binding of the unknown factor; hence, we considered it the likeliest candidate. Electrophoretic mobility shift assays confirmed cross-reactivity between the unknown repressor and anti-ets-2 antibodies, and cotransfection experiments demonstrated the direct involvement of Ets-2 in silencing the IL-2 promoter. Designing experiments for transcription factor analysis using microarrays and Bayesian statistical methodologies provides a novel way toward elucidation of gene control networks.
Collapse
Affiliation(s)
- C Argyropoulos
- Laboratory of Hematology and Transfusion Medicine, University of Patras, Patras, Greece
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Wang Z, Wang DZ, Hockemeyer D, McAnally J, Nordheim A, Olson EN. Myocardin and ternary complex factors compete for SRF to control smooth muscle gene expression. Nature 2004; 428:185-9. [PMID: 15014501 DOI: 10.1038/nature02382] [Citation(s) in RCA: 452] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Accepted: 01/26/2004] [Indexed: 12/17/2022]
Abstract
Smooth muscle cells switch between differentiated and proliferative phenotypes in response to extracellular cues, but the transcriptional mechanisms that confer such phenotypic plasticity remain unclear. Serum response factor (SRF) activates genes involved in smooth muscle differentiation and proliferation by recruiting muscle-restricted cofactors, such as the transcriptional coactivator myocardin, and ternary complex factors (TCFs) of the ETS-domain family, respectively. Here we show that growth signals repress smooth muscle genes by triggering the displacement of myocardin from SRF by Elk-1, a TCF that acts as a myogenic repressor. The opposing influences of myocardin and Elk-1 on smooth muscle gene expression are mediated by structurally related SRF-binding motifs that compete for a common docking site on SRF. A mutant smooth muscle promoter, retaining responsiveness to myocardin and SRF but defective in TCF binding, directs ectopic transcription in the embryonic heart, demonstrating a role for TCFs in suppression of smooth muscle gene expression in vivo. We conclude that growth and developmental signals modulate smooth muscle gene expression by regulating the association of SRF with antagonistic cofactors.
Collapse
Affiliation(s)
- Zhigao Wang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, Texas 75390-9148, USA
| | | | | | | | | | | |
Collapse
|
30
|
Abstract
The three ternary complex factors (TCFs) Elk-1, Net and Sap-1 form a subfamily of the E twenty-six (Ets) domain transcription factors. Their characteristic property is the ability to form a ternary nucleoprotein complex with the serum response factor (SRF) over the serum response element (SRE) of the c-fos promoter. The molecular mechanisms that underlie the function and regulation of these factors have been extensively studied and the TCFs are a paradigm for the study of transcriptional regulation in response to extracellular signalling through the mitogen-activated protein (MAP) kinase pathway. As final effectors of multiple signalling pathways and components of protein complexes on immediate early promoters, they represent key elements in the complex and dynamic regulation of gene expression. This review summarises the molecular, structural and biochemical studies that have led to the understanding of the functional domains of the TCFs, ternary complex formation, transcriptional regulation, protein partners and target genes in cell lines. Finally, the emerging studies of the biological roles of the TCFs in vivo will be discussed.
Collapse
Affiliation(s)
- Gilles Buchwalter
- Institut de Génétique et Biologie Moléculaire et Cellulaire, 1 rue Laurent Fries, BP 101142, CNRS, INSERM, ULP, 67404 Illkirch Cedex, France
| | | | | |
Collapse
|
31
|
Gao R, Ball DK, Perbal B, Brigstock DR. Connective tissue growth factor induces c-fos gene activation and cell proliferation through p44/42 MAP kinase in primary rat hepatic stellate cells. J Hepatol 2004; 40:431-8. [PMID: 15123357 DOI: 10.1016/j.jhep.2003.11.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Revised: 10/08/2003] [Accepted: 11/06/2003] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Connective tissue growth factor (CCN2) is expressed during activation of hepatic stellate cells (HSC) and promotes HSC proliferation, adhesion, and collagen production. The aim of the study was to investigate CCN2 signaling pathways in HSC. METHODS Primary HSC were obtained by enzymatic perfusion of rat liver. DNA synthesis was evaluated by [(3)H]thymidine incorporation. Phosphorylation of Elk-1, extracellular signal-regulated kinase (ERK1/2) and focal adhesion kinase (FAK) was evaluated by Western blot. Transcriptional factor binding activity was determined by gel mobility shift assay while c-fos promoter and CCN2 promoter activity was evaluated using luciferase reporters. c-fos mRNA expression was evaluated by Northern blot. RESULTS CCN2 stimulated DNA synthesis and phosphorylation of FAK, Elk-1 and ERK1/2, the latter of which was blocked by heparin. The serum response element binding activity and luciferase reporter activity of the c-fos promoter, together with expression of c-fos, were enhanced by CCN2. CCN2-induced c-fos gene activation, expression and cell proliferation were blocked by inhibiting ERK1/2 with PD98059. CCN2 promoter activity was enhanced by TGF-beta1 or PDGF via a Smad7-dependent pathway. CONCLUSIONS CCN2-stimulated HSC DNA synthesis is associated with transient induction of c-fos gene activation and expression as well as activation of the ERK1/2 signal pathway.
Collapse
Affiliation(s)
- Runping Gao
- Laboratoire d'Oncologie Virale et Moléculaire, Université Paris 7, Diderot 75005, France
| | | | | | | |
Collapse
|
32
|
Ano S, Pereira R, Pironin M, Lesault I, Milley C, Lebigot I, Quang CT, Ghysdael J. Erythroblast transformation by FLI-1 depends upon its specific DNA binding and transcriptional activation properties. J Biol Chem 2003; 279:2993-3002. [PMID: 14570912 DOI: 10.1074/jbc.m303816200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
FLI-1 is a transcriptional regulator of the ETS family of proteins. Insertional activation at the FLI-1 locus is an early event in F-murine leukemia virus-induced erythroleukemia. Consistent with its essential role in erythroid transformation, enforced expression of FLI-1 in primary erythroblasts strongly impairs the response of these cells to erythropoietin (Epo), a cytokine essential to erythropoiesis. We show here that point mutations in the ETS domain that abolished FLI-1 binding to specific DNA elements (ETS-binding sites) suppressed the ability of FLI-1 to transform erythroblasts. The exchange of the entire ETS domain (DNA binding domain) of FLI-1 for that of PU.1 changed the DNA binding specificity of FLI-1 for that of PU.1 and impaired FLI-1 transforming properties. In contrast, ETS domain swapping mutants that maintained the DNA binding specificity of FLI-1 did not affect the ability of FLI-1 to transform erythroblasts. Deletion and swapping mutants that failed to inhibit the DNA binding activity of FLI-1 but impaired its transcriptional activation properties were also transformation-defective. Taken together, these results show that both the ability of FLI-1 to inhibit Epo-induced differentiation of erythroblasts and to confer enhanced cell survival in the absence of Epo critically depend upon FLI-1 ETS-binding site-dependent transcriptional activation properties.
Collapse
Affiliation(s)
- Sabine Ano
- CNRS UMR 146, Institut Curie, Centre Universitaire, Bâatiment 110, 91405 Orsay, France
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Mora-Garcia P, Cheng J, Crans-Vargas HN, Countouriotis A, Shankar D, Sakamoto KM. Transcriptional regulators and myelopoiesis: the role of serum response factor and CREB as targets of cytokine signaling. Stem Cells 2003; 21:123-30. [PMID: 12634408 DOI: 10.1634/stemcells.21-2-123] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hematopoiesis is a complex process in which mature myeloid and lymphoid cells are produced from a small population of pluripotent stem cells within the bone marrow. Blood cell formation occurs, in part, by progenitor cell exposure to humoral growth regulators, known as hematopoietic cytokines, as well as by the regulated expression of genes by transcription factors. In this paper, we review two important nuclear proteins, the serum response factor and the cyclic adenosine monophosphate response element-binding protein, as downstream targets of mitogens, with a specific focus on hematopoietic cytokine signaling and the role these proteins play in gene regulation.
Collapse
Affiliation(s)
- Patricia Mora-Garcia
- Department of Pediatrics, Division of Hematology-Oncology, Mattel Children's Hospital, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA
| | | | | | | | | | | |
Collapse
|
34
|
Yang SH, Bumpass DC, Perkins ND, Sharrocks AD. The ETS domain transcription factor Elk-1 contains a novel class of repression domain. Mol Cell Biol 2002; 22:5036-46. [PMID: 12077333 PMCID: PMC139783 DOI: 10.1128/mcb.22.14.5036-5046.2002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ETS domain transcription factor Elk-1 serves as an integration point for different mitogen-activated protein (MAP) kinase pathways. Phosphorylation of Elk-1 by MAP kinases triggers its activation. However, while the activation process is well understood, its downregulation-inactivation is less well characterized. The ETS DNA-binding domain plays a role in the downregulation of Elk-dependent promoter activity following mitogenic activation by recruiting the mSin3A-HDAC complex. Here we have identified a novel evolutionarily conserved repression domain in Elk-1, termed the R motif, which serves to reduce the basal transcriptional activity of Elk-1 and dampen its response to mitogenic signals. This domain is highly potent and portable and can repress transcription in trans. The R motif is related to the CRD1 repression domain in p300 and can functionally replace this domain and confer p21(waf1/cip1) inducibility on p300. However, the R motif acts in a context-dependent manner and is not p21(waf1/cip1) responsive in Elk-1. Thus, the Elk-1 R motif and the p300 CRD1 motif represent a new class of repression domains that are regulated in a context-dependent manner.
Collapse
Affiliation(s)
- Shen-Hsi Yang
- School of Biological Sciences, University of Manchester, 2205 Stopford Building, Oxford Road, Manchester M13 9PT, UK
| | | | | | | |
Collapse
|
35
|
Shore P, Dietrich W, Corcoran LM. Oct-2 regulates CD36 gene expression via a consensus octamer, which excludes the co-activator OBF-1. Nucleic Acids Res 2002; 30:1767-73. [PMID: 11937630 PMCID: PMC113195 DOI: 10.1093/nar/30.8.1767] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The POU domain transcription factor, Oct-2, is essential for the B cell-specific expression of CD36 in mouse B cells. In order to determine how Oct-2 mediates expression of CD36 in B cells, we cloned and analysed the mouse CD36 promoter. In contrast to the human CD36 promoter, the mouse promoter contains a consensus octamer element of the type ATGCTAAT. This octamer element can be bound by either Oct-1 or Oct-2 but requires the expression of Oct-2 to activate transcription in B cells. Mutation of the octamer element renders the CD36 promoter refractory to activation by Oct-2. Furthermore, we demonstrate that the CD36 octamer element does not support recruitment of the B cell-specific co-activator OBF-1 and that CD36 expression is unaffected in primary B cells derived from obf-1(-/-) mice. We conclude that Oct-2 activates CD36 gene expression in mouse B cells via the octamer element in the promoter. Our data also demonstrate that CD36 is the first example of an Oct-2-dependent gene whose expression in B cells is independent of OBF-1. These findings support the notion that Oct-2 regulates gene transcription by both OBF-1-dependent and -independent mechanisms.
Collapse
Affiliation(s)
- Paul Shore
- School of Biological Sciences, University of Manchester, 2.205, Stopford Building, Oxford Road, Manchester M13 9PT, UK.
| | | | | |
Collapse
|
36
|
Abstract
Ets proteins are a family of transcription factors that regulate the expression of a myriad of genes in a variety of tissues and cell types. This functional versatility emerges from their interactions with other structurally unrelated transcription factors. Indeed, combinatorial control is a characteristic property of Ets family members, involving interactions between Ets and other key transcriptional factors such as AP1, SRF, and Pax family members. Intriguingly, recent molecular modeling and crystallographic data suggest that not only the ETS DNA-binding domain, but also the DNA recognition helix alpha3, are often directly required for Ets partner's selection. Indeed, while most DNA-binding proteins appear to exploit differences within their DNA recognition helices for sites selection, the Ets proteins exploit differences in their surfaces that interact with other transcription factors, which in turn may modify their DNA-binding properties in a promoter-specific fashion. Taken together, the gene-specific architecture of these unique complexes can mediate the selective control of transcriptional activity.
Collapse
Affiliation(s)
- Alexis Verger
- CNRS UMR 8526, Institut de Biologie de Lille, B.P. 447, 1 rue Calmette, 59021 Lille Cedex, France
| | | |
Collapse
|
37
|
Graham TE, Prossnitz ER, Dorin RI. Dexras1/AGS-1 inhibits signal transduction from the Gi-coupled formyl peptide receptor to Erk-1/2 MAP kinases. J Biol Chem 2002; 277:10876-82. [PMID: 11751935 DOI: 10.1074/jbc.m110397200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dexras1 is a novel GTP-binding protein (G protein) that was recently discovered on the basis of rapid mRNA up-regulation by glucocorticoids in murine AtT-20 corticotroph cells and in several primary tissues. The human homologue of Dexras1, termed activator of G protein signaling-1 (AGS-1), has been reported to stimulate signaling by G(i) heterotrimeric G proteins independently of receptor activation. The effects of Dexras1/AGS-1 on receptor-initiated signaling by G(i) have not been examined. Here we report that Dexras1 inhibits ligand-dependent signaling by the G(i)-coupled N-formyl peptide receptor (FPR). Dexras1 and FPR were transiently co-expressed in both COS-7 and HEK-293 cells. Activation of FPR by ligand (N-formyl-methionine-leucine-phenylalanine (f-MLF)) caused phosphorylation of endogenous Erk-1/2 that was reduced by co-expression of Dexras1. Direct effects of Dexras1 on the activity of co-expressed, epitope-tagged Erk-2 (hemagglutinin (HA)-Erk-2) were measured by immune complex in vitro kinase assay. Expression of Dexras1 alone resulted in a 1.9- to 4.9-fold increase in HA-Erk-2 activity; expression of the unliganded FPR alone resulted in a 6.2- to 8.1-fold increase in HA-Erk-2 activity. Stimulation of FPR by f-MLF produced a further 8- to 10-fold increase in HA-Erk-2 activity over the basal (non-ligand-stimulated) state, and this ligand-dependent activity was attenuated at the time points of maximal activity by co-expression of Dexras1 (reduced 31 +/- 6.8% in COS-7 at 10 min and 86 +/- 9.2% in HEK-293 at 5 min, p < 0.01 for each). Expression of Dexras1 did not influence protein expression of FPR or Erk, suggesting that the inhibitory effects of Dexras1 reflect a functional alteration in the signaling cascade from FPR to Erk. Expression of Dexras1 had no effect on expression of G(i)alpha species, but significantly impaired pertussis toxin-catalyzed ADP-ribosylation of membrane-associated G(i)alpha. Expression of Dexras1 also significantly decreased in vitro binding of GTPgammaS in f-MLF-stimulated membranes of cells co-transfected with FPR. These data suggest that Dexras1 inhibits signal transduction from FPR to Erk-1/2 through an effect that is very proximal to receptor-G(i) coupling. While Dexras1 weakly activates Erk in the resting state, more potent effects are evident in the modulation of ligand-stimulated receptor signal transduction, where Dexras1 functions as an inhibitor rather than activator of the Erk mitogen-activated protein kinase signaling cascade.
Collapse
Affiliation(s)
- Timothy E Graham
- New Mexico Veterans Affairs Health Care System, Albuquerque, New Mexico 87108, USA
| | | | | |
Collapse
|
38
|
Mo Y, Ho W, Johnston K, Marmorstein R. Crystal structure of a ternary SAP-1/SRF/c-fos SRE DNA complex. J Mol Biol 2001; 314:495-506. [PMID: 11846562 DOI: 10.1006/jmbi.2001.5138] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Combinatorial DNA binding by proteins for promoter-specific gene activation is a common mode of DNA regulation in eukaryotic organisms, and occurs at the promoter of the c-fos proto-oncogene. The c-fos promoter contains a serum response element (SRE) that mediates ternary complex formation with the Ets proteins SAP-1 or Elk-1 and the MADS-box protein, serum response factor (SRF). Here, we report the crystal structure of a ternary SAP-1/SRF/c-fos SRE DNA complex containing the minimal DNA-binding domains of each protein. The structure of the complex reveals that the SAP-1 monomer and SRF dimer are bound on opposite faces of the DNA, and that the DNA recognition helix of SAP-1 makes direct contact with the DNA recognition helix of one of the two SRF subunits. These interactions facilitate an 82 degrees DNA bend around SRF and a modulation of protein-DNA contacts by each protein when compared to each of the binary DNA complexes. A comparison with a recently determined complex containing SRF, an idealized DNA site, and a SAP-1 fragment containing a SRF-interacting B-box region, shows a similar overall architecture but also shows important differences. Specifically, the comparison suggests that the B-box region of the Ets protein does not significantly influence DNA recognition by either of the proteins, and that the sequence of the DNA target effects the way in which the two proteins cooperate for DNA recognition. These studies have implications for how DNA-bound SRF may modulate the DNA-binding properties of other Ets proteins such as Elk-1, and for how other Ets proteins may modulate the DNA-binding properties of other DNA-bound accessory factors to facilitate promoter-specific transcriptional responses.
Collapse
Affiliation(s)
- Y Mo
- The Wistar Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | | | | |
Collapse
|
39
|
Abstract
ETS-domain transcription-factor networks represent a model for how combinatorial gene expression is achieved. These transcription factors interact with a multitude of co-regulatory partners to elicit gene-specific responses and drive distinct biological processes. These proteins are controlled by a complex series of inter and intramolecular interactions, and signalling pathways impinge on these proteins to further regulate their action.
Collapse
Affiliation(s)
- A D Sharrocks
- School of Biological Sciences, University of Manchester, 2.205 Stopford Building, Oxford Road, Manchester, M13 9PT, UK.
| |
Collapse
|
40
|
Fitzsimmons D, Lutz R, Wheat W, Chamberlin HM, Hagman J. Highly conserved amino acids in Pax and Ets proteins are required for DNA binding and ternary complex assembly. Nucleic Acids Res 2001; 29:4154-65. [PMID: 11600704 PMCID: PMC60220 DOI: 10.1093/nar/29.20.4154] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Combinatorial association of DNA-binding proteins on composite binding sites enhances their nucleotide sequence specificity and functional synergy. As a paradigm for these interactions, Pax-5 (BSAP) assembles ternary complexes with Ets proteins on the B cell-specific mb-1 promoter through interactions between their respective DNA-binding domains. Pax-5 recruits Ets-1 to bind the promoter, but not the closely related Ets protein SAP1a. Here we show that, while several different mutations increase binding of SAP1a to an optimized Ets binding site, only conversion of Val68 to an acidic amino acid facilitates ternary complex assembly with Pax-5 on the mb-1 promoter. This suggests that enhanced DNA binding by SAP1a is not sufficient for recruitment by Pax-5, but instead involves protein-protein interactions mediated by the acidic side chain. Recruitment of Ets proteins by Pax-5 requires Gln22 within the N-terminal beta-hairpin motif of its paired domain. The beta-hairpin also participates in recognition of a subset of Pax-5-binding sites. Thus, Pax-5 incorporates protein-protein interaction and DNA recognition functions in a single motif. The Caenorhabditis elegans Pax protein EGL-38 also binds specifically to the mb-1 promoter and recruits murine Ets-1 or the C.elegans Ets protein T08H4.3, but not the related LIN-1 protein. Together, our results define specific amino acid requirements for Pax-Ets ternary complex assembly and show that the mechanism is conserved between evolutionarily related proteins of diverse animal species. Moreover, the data suggest that interactions between Pax and Ets proteins are an important mechanism that regulates fundamental biological processes in worms and humans.
Collapse
Affiliation(s)
- D Fitzsimmons
- Integrated Department of Immunology, University of Colorado Health Sciences Center, Denver, CO 80262, USA
| | | | | | | | | |
Collapse
|
41
|
Hassler M, Richmond TJ. The B-box dominates SAP-1-SRF interactions in the structure of the ternary complex. EMBO J 2001; 20:3018-28. [PMID: 11406578 PMCID: PMC150215 DOI: 10.1093/emboj/20.12.3018] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The serum response element (SRE) is found in several immediate-early gene promoters. This DNA sequence is necessary and sufficient for rapid transcriptional induction of the human c-fos proto-oncogene in response to stimuli external to the cell. Full activation of the SRE requires the cooperative binding of a ternary complex factor (TCF) and serum response factor (SRF) to their specific DNA sites. The X-ray structure of the human SAP-1-SRF-SRE DNA ternary complex was determined (Protein Data Bank code 1hbx). It shows SAP-1 TCF bound to SRF through interactions between the SAP-1 B-box and SRF MADS domain in addition to contacts between their respective DNA-binding motifs. The SAP-1 B-box is part of a flexible linker of which 21 amino acids become ordered upon ternary complex formation. Comparison with a similar region from the yeast MATalpha2-MCM1-DNA complex suggests a common binding motif through which MADS-box proteins may interact with additional factors such as Fli-1.
Collapse
Affiliation(s)
| | - Timothy J. Richmond
- ETH Zürich, Institut für Molekularbiologie und Biophysik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
Corresponding author e-mail:
| |
Collapse
|
42
|
Greenall A, Willingham N, Cheung E, Boam DS, Sharrocks AD. DNA binding by the ETS-domain transcription factor PEA3 is regulated by intramolecular and intermolecular protein.protein interactions. J Biol Chem 2001; 276:16207-15. [PMID: 11278941 DOI: 10.1074/jbc.m011582200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The control of DNA binding by eukaryotic transcription factors represents an important regulatory mechanism. Many transcription factors are controlled by cis-acting autoinhibitory modules that are thought to act by blocking promiscuous DNA binding in the absence of appropriate regulatory cues. Here, we have investigated the determinants and regulation of the autoinhibitory mechanism employed by the ETS-domain transcription factor, PEA3. DNA binding is inhibited by a module composed of a combination of two short motifs located on either side of the ETS DNA-binding domain. A second type of protein, Ids, can act in trans to mimic the effect of these cis-acting inhibitory motifs and reduce DNA binding by PEA3. By using a one-hybrid screen, we identified the basic helix-loop-helix-leucine zipper transcription factor USF-1 as an interaction partner for PEA3. PEA3 and USF-1 form DNA complexes in a cooperative manner. Moreover, the formation of ternary PEA3.USF-1.DNA complexes requires parts of the same motifs in PEA3 that form the autoinhibitory module. Thus the binding of USF-1 to PEA3 acts as a switch that modifies the autoinhibitory motifs in PEA3 to first relieve their inhibitory action, and second, promote ternary nucleoprotein complex assembly.
Collapse
Affiliation(s)
- A Greenall
- School of Biochemistry and Genetics, The Medical School, University of Newcastle Upon Tyne, Newcastle Upon Tyne NE2 4HH, United Kingdom
| | | | | | | | | |
Collapse
|
43
|
Withers DA, Hakomori SI. Human alpha (1,3)-fucosyltransferase IV (FUTIV) gene expression is regulated by elk-1 in the U937 cell line. J Biol Chem 2000; 275:40588-93. [PMID: 11006292 DOI: 10.1074/jbc.m007262200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The alpha1,3-fucosyltransferase IV (FucTIV) encoded by its gene (FUTIV) is responsible for synthesis of Le(x) (Galbeta4[Fucalpha3]GlcNAcbeta3Galbeta1,R), which causes compaction in the morula stage of the preimplantation mouse embryo, as well as alpha1,3-fucosylation at multiple internal GlcNAc of unbranched poly-N-acetyllactosamine, termed "myeloglycan," the physiological epitope of E-selectin. Since myeloglycan-type structure is also expressed in various types of human cancer and may mediate E-selectin-dependent metastasis, expression of FUTIV is oncodevelopmentally regulated. The mechanisms controlling FUTIV expression remain to be clarified. In this report, we further characterize FUTIV gene structure and define a non-TATA box-dependent transcriptional start region just upstream from the translational start. FUTIV promoter/reporter fusion constructs defined a "full-length" promoter and highly active fragments in the macrophage-derived U937 and myeloid HL60 cell lines. One highly active fragment contains a consensus binding site for the Ets-1 transcription factor (Withers, D. A., and Hakomori, S. (1997) Glycoconj. J. 14, 764). Gel shift analysis shows specific binding to this site in nuclear extracts from U937 cells. Mutation of the Ets consensus site significantly reduces FUTIV promoter activity in both cell lines. Gel supershift and dominant negative cotransfection experiments identified the Ets family member Elk-1 as one component binding and regulating the FUTIV promoter in U937 cells. The significance of FUTIV regulation by Elk-1 is discussed.
Collapse
Affiliation(s)
- D A Withers
- Pacific Northwest Research Institute, Seattle, Washington 98122, USA.
| | | |
Collapse
|
44
|
Identification and characterization of a new human ETS-family transcription factor, TEL2, that is expressed in hematopoietic tissues and can associate with TEL1/ETV6. Blood 2000. [DOI: 10.1182/blood.v95.11.3341] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
The ETS family of proteins is a large group of transcription factors implicated in many aspects of normal hematopoietic development, as well as oncogenesis. For example, the TEL1/ETV6 (TEL1) gene is required for normal yolk sac angiogenesis, adult bone marrow hematopoiesis, and is rearranged or deleted in numerous leukemias. This report describes the cloning and characterization of a novelETS gene that is highly related to TEL1 and is therefore called TEL2. The TEL2 gene consists of 8 exons spanning approximately 21 kilobases (kb) in human chromosome 6p21. Unlike the ubiquitously expressed TEL1 gene, however,TEL2 appears to be expressed predominantly in hematopoietic tissues. Antibodies raised against the C-terminus of the TEL2 protein were used to show that TEL2 localizes to the nucleus. All ETS proteins can bind DNA via the highly conserved ETS domain, which recognizes a purine-rich DNA sequence with a GGAA core motif. DNA binding assays show that TEL2 can bind the same consensus DNA binding sequence recognized by TEL1/ETV6. Additionally, the TEL2 protein is capable of associating with itself and with TEL1 in doubly transfected Hela cells, and this interaction is mediated through the pointed (PNT) domain of TEL1. The striking similarities ofTEL2 to the oncogenic TEL1, its expression in hematopoietic tissues, and its ability to associate withTEL1 suggest that TEL2 may be an important hematopoietic regulatory protein.
Collapse
|
45
|
Identification and characterization of a new human ETS-family transcription factor, TEL2, that is expressed in hematopoietic tissues and can associate with TEL1/ETV6. Blood 2000. [DOI: 10.1182/blood.v95.11.3341.011k44_3341_3348] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ETS family of proteins is a large group of transcription factors implicated in many aspects of normal hematopoietic development, as well as oncogenesis. For example, the TEL1/ETV6 (TEL1) gene is required for normal yolk sac angiogenesis, adult bone marrow hematopoiesis, and is rearranged or deleted in numerous leukemias. This report describes the cloning and characterization of a novelETS gene that is highly related to TEL1 and is therefore called TEL2. The TEL2 gene consists of 8 exons spanning approximately 21 kilobases (kb) in human chromosome 6p21. Unlike the ubiquitously expressed TEL1 gene, however,TEL2 appears to be expressed predominantly in hematopoietic tissues. Antibodies raised against the C-terminus of the TEL2 protein were used to show that TEL2 localizes to the nucleus. All ETS proteins can bind DNA via the highly conserved ETS domain, which recognizes a purine-rich DNA sequence with a GGAA core motif. DNA binding assays show that TEL2 can bind the same consensus DNA binding sequence recognized by TEL1/ETV6. Additionally, the TEL2 protein is capable of associating with itself and with TEL1 in doubly transfected Hela cells, and this interaction is mediated through the pointed (PNT) domain of TEL1. The striking similarities ofTEL2 to the oncogenic TEL1, its expression in hematopoietic tissues, and its ability to associate withTEL1 suggest that TEL2 may be an important hematopoietic regulatory protein.
Collapse
|
46
|
Huang Y, Deng T, Winston BW. Characterization of hPRP4 kinase activation: potential role in signaling. Biochem Biophys Res Commun 2000; 271:456-63. [PMID: 10799319 DOI: 10.1006/bbrc.2000.2651] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) and cyclin-dependent kinases (CDKs) are important proline-directed Ser/Thr kinases that play distinct roles in cell differentiation and proliferation. hPRP4 (pre-mRNA processing gene), a human homologue of S. pombe Prp4, is a recently isolated CDK-like kinase with homology to MAPKs. Little is known about the mRNA processing function of hPRP4 or about the signaling pathways with which it is associated. hPRP4 is expressed in a variety of human tissues with the highest expression in the brain, lung and liver. In this paper, we characterize the activation of hPRP4 in COS-7 cells and show that hPRP4 also possesses a transcription factor activation function. hPRP4 is activated by epidermal growth factor (EGF) or forskolin treatment, but not tetradecanoyl phorbol acetate (TPA) nor ultraviolet (UV) irradiation. Activated hPRP4 phosphorylates residue Thr-417 on Elk-1 resulting in Elk-1 activation. This site of Elk-1 phosphorylation is distinct from that of other MAPKs. Coexpression of hPRP4 with an Elk-1 reporter construct causes trans activation of the reporter. These findings suggest that hPRP4, a CDK-like kinase related to MAPKs, may play a distinct role in signal transduction in addition to its role in mRNA processing.
Collapse
Affiliation(s)
- Y Huang
- Department of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | | | | |
Collapse
|
47
|
Brown LA, Yang SH, Hair A, Galanis A, Sharrocks AD. Molecular characterization of a zebrafish TCF ETS-domain transcription factor. Oncogene 1999; 18:7985-93. [PMID: 10637509 DOI: 10.1038/sj.onc.1203197] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ternary complex factor (TCF) subfamily of ETS-transcription factors represent key nuclear targets of the MAP kinase pathways. Members of this subfamily are classified by the presence of several conserved domains for DNA binding, interaction with SRF, interaction with MAP kinases and transcriptional activation. In this study we have isolated a further member of this subfamily (TCF-1) from zebrafish. The protein product of zebrafish TCF-1 (zTCF-1), shares sequence similarity with the mammalian TCFs in all four conserved domains, with highest overall similarity to SAP-1. Zebrafish TCF-1 is expressed throughout zebrafish embryonic development and exhibits typical TCF DNA binding characteristics, with the B-box being required for interaction with SRF. Of the mammalian TCFs, its DNA binding specificity resembles Elk-1. zTCF-1 is a target for both the growth factor/mitogen-activated and stress-activated MAP kinase cascades in vitro and in vivo. However, differential targeting occurs, with the profile of its activation closely resembling that of mammalian SAP-1. Together, our results demonstrate that the TCFs have been functionally conserved during vertebrate development.
Collapse
Affiliation(s)
- L A Brown
- Department of Biochemistry and Genetics, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, NE2 4HH, UK
| | | | | | | | | |
Collapse
|
48
|
Clarkson RW, Shang CA, Levitt LK, Howard T, Waters MJ. Ternary complex factors Elk-1 and Sap-1a mediate growth hormone-induced transcription of egr-1 (early growth response factor-1) in 3T3-F442A preadipocytes. Mol Endocrinol 1999; 13:619-31. [PMID: 10194767 DOI: 10.1210/mend.13.4.0266] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In our search for transcription factors induced by GH, we have analyzed immediate early gene activation in a model of GH-dependent differentiation. Here we describe the activation of early growth response factor-1 (egr-1) in GH-stimulated 3T3-F442A preadipocytes and the transcription factors responsible for its transactivation. Binding activity of egr-1 in electrophoretic mobility shift assay (EMSA) increased transiently 1 h after GH stimulation, accompanied by a concomitant increase in egr-1 mRNA. egr-1 induction appeared not to be related to proliferation since it was amplified in quiescent preadipocytes at a time when cells were refractive to GH-stimulated DNA synthesis. Truncations of the proximal 1 kb of the egr-1 promoter revealed that a 374-bp region (-624 to -250) contributes about 80% of GH inducibility in 3T3-F442A cells and approximately 90% inducibility in CHO-K1 cells. This region contains three juxtaposed SRE (serum response element)/Ets site pairs known to be important for egr-1 activity in response to exogenous stimuli. Site-specific mutations of individual SRE and Ets sites within this region each reduced GH inducibility of the promoter. Use of these site-specific mutations in EMSA showed that disruption of either Ets or SRE sites abrogated ternary complex formation at the composite sites. DNA binding of ternary complexes, but not binary complexes, in EMSA was rapidly and transiently increased by GH. EMSA supershifts indicated these ternary complexes contained serum response factor (SRF) and the Ets factors Elk-1 and Sap-1a. Coexpression of Sap-1a and Elk-1 resulted in a marked increase in GH induction of egr-1 promoter activity, although transfection with expression vectors for either Ets factor alone did not significantly enhance the GH response. We conclude that GH stimulates transcription of egr-1 primarily through activation of these Ets factors at multiple sites on the promoter and that stabilization of ternary complexes with SRF at these sites maximizes this response.
Collapse
Affiliation(s)
- R W Clarkson
- Department of Physiology and Pharmacology, University Queensland, St. Lucia, Australia
| | | | | | | | | |
Collapse
|
49
|
Yates PR, Atherton GT, Deed RW, Norton JD, Sharrocks AD. Id helix-loop-helix proteins inhibit nucleoprotein complex formation by the TCF ETS-domain transcription factors. EMBO J 1999; 18:968-76. [PMID: 10022839 PMCID: PMC1171189 DOI: 10.1093/emboj/18.4.968] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The Id subfamily of helix-loop-helix (HLH) proteins plays a fundamental role in the regulation of cellular proliferation and differentiation. Id proteins are thought to inhibit differentiation mainly through interaction with other HLH proteins and by blocking their DNA-binding activity. Members of the ternary complex factor (TCF) subfamily of ETS-domain proteins have key functions in regulating immediate-early gene expression in response to mitogenic stimulation. TCFs form DNA-bound complexes with the serum response factor (SRF) and are direct targets of MAP kinase (MAPK) signal transduction cascades. In this study we demonstrate functional interactions between Id proteins and TCFs. Ids bind to the ETS DNA-binding domain and disrupt the formation of DNA-bound complexes between TCFs and SRF on the c-fos serum response element (SRE). Inhibition occurs by disrupting protein-DNA interactions with the TCF component of this complex. In vivo, the Id proteins cause down-regulation of the transcriptional activity mediated by the TCFs and thereby block MAPK signalling to SREs. Therefore, our results demonstrate a novel facet of Id function in the coordination of mitogenic signalling and cell cycle entry.
Collapse
Affiliation(s)
- P R Yates
- Department of Biochemistry and Genetics, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, NE2 4HH
| | | | | | | | | |
Collapse
|
50
|
Lutfiyya LL, Iyer VR, DeRisi J, DeVit MJ, Brown PO, Johnston M. Characterization of three related glucose repressors and genes they regulate in Saccharomyces cerevisiae. Genetics 1998; 150:1377-91. [PMID: 9832517 PMCID: PMC1460414 DOI: 10.1093/genetics/150.4.1377] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mig1 and Mig2 are proteins with similar zinc fingers that are required for glucose repression of SUC2 expression. Mig1, but not Mig2, is required for repression of some other glucose-repressed genes, including the GAL genes. A second homolog of Mig1, Yer028, appears to be a glucose-dependent transcriptional repressor that binds to the Mig1-binding sites in the SUC2 promoter, but is not involved in glucose repression of SUC2 expression. Despite their functional redundancy, we found several significant differences between Mig1 and Mig2: (1) in the absence of glucose, Mig1, but not Mig2, is inactivated by the Snf1 protein kinase; (2) nuclear localization of Mig1, but not Mig2, is regulated by glucose; (3) expression of MIG1, but not MIG2, is repressed by glucose; and (4) Mig1 and Mig2 bind to similar sites but with different relative affinities. By two approaches, we have identified many genes regulated by Mig1 and Mig2, and confirmed a role for Mig1 and Mig2 in repression of several of them. We found no genes repressed by Yer028. Also, we identified no genes repressed by only Mig1 or Mig2. Thus, Mig1 and Mig2 are redundant glucose repressors of many genes.
Collapse
Affiliation(s)
- L L Lutfiyya
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
| | | | | | | | | | | |
Collapse
|