1
|
Custom G4 Microarrays Reveal Selective G-Quadruplex Recognition of Small Molecule BMVC: A Large-Scale Assessment of Ligand Binding Selectivity. Molecules 2020; 25:molecules25153465. [PMID: 32751510 PMCID: PMC7436161 DOI: 10.3390/molecules25153465] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/24/2020] [Accepted: 07/25/2020] [Indexed: 11/17/2022] Open
Abstract
G-quadruplexes (G4) are considered new drug targets for human diseases such as cancer. More than 10,000 G4s have been discovered in human chromatin, posing challenges for assessing the selectivity of a G4-interactive ligand. 3,6-bis(1-Methyl-4-vinylpyridinium) carbazole diiodide (BMVC) is the first fluorescent small molecule for G4 detection in vivo. Our previous structural study shows that BMVC binds to the MYC promoter G4 (MycG4) with high specificity. Here, we utilize high-throughput, large-scale custom DNA G4 microarrays to analyze the G4-binding selectivity of BMVC. BMVC preferentially binds to the parallel MycG4 and selectively recognizes flanking sequences of parallel G4s, especially the 3′-flanking thymine. Importantly, the microarray results are confirmed by orthogonal NMR and fluorescence binding analyses. Our study demonstrates the potential of custom G4 microarrays as a platform to broadly and unbiasedly assess the binding selectivity of G4-interactive ligands, and to help understand the properties that govern molecular recognition.
Collapse
|
2
|
Sengupta P, Chatterjee S. Inosine 5'-diphosphate, a molecular decoy rescues Nucleoside diphosphate kinase from c-MYC G-Quadruplex unfolding. Biochim Biophys Acta Gen Subj 2020; 1864:129649. [PMID: 32492501 DOI: 10.1016/j.bbagen.2020.129649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/02/2020] [Accepted: 05/27/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND The transcription-inhibitory G-Quadruplex(Pu27-GQ) at c-MYC promoter is challenging to target due to structural heterogeneity. Nucleoside diphosphate kinase (NM23-H2) specifically binds and unfolds Pu27-GQ to increase c-MYC transcription. Here, we used Inosine 5'-diphosphate (IDP) to disrupt NM23-H2-Pu27-GQ interactions and arrest c-MYC transcription without compromising NM23-H2-mediated kinase properties. METHODS Site-directed mutagenesis,31P-NMR and STD-NMR studies delineate the epitope of NM23-H2-IDP complex and characterize specific amino acids in NM23-H2 involved in Pu27-GQ and IDP interactions. Immunoprecipitations and phosphohistidine-immunoblots reveal how IDP blocks NM23-H2-Pu27 association to downregulate c-MYC transcription in MDAMB-231 cells exempting NM23-H2-mediated kinase properties. RESULTS NMR studies show that IDP binds to the Guanosine diphosphate-binding pocket of NM23-H2 (KD = 5.0 ± 0.276 μM). Arg88-driven hydrogen bonds to the terminal phosphate of IDP restricts P-O-P bond-rotation increasing its pKa (∆pKa = 0.85 ± 0.0025).9-inosinyl moiety of IDP is stacked over Phe60 phenyl ring driving trans-conformation of inosine and axial geometry of pyrophosphates. Chromatin immunoprecipitations revealed that these interactions rescue NM23-H2-driven Pu27-GQ unfolding, which triggers Nucleolin recruitment and lowers Sp1 occupancy at c-MYC promoter stabilizing Pu27-GQ. This silences c-MYC transcription that reduces c-MYC-Sp1 association amplifying Sp1 recruitment across P21 promoter stimulating P21 transcription and G2/M arrest. CONCLUSIONS IDP synergizes the effects of Pu27-GQ-interacting compounds to abrogate c-MYC transcription and induce apoptosis in MDAMB-231 cells by disrupting NM23-H2-Pu27-GQ interactions without affecting NM23-H2-mediated kinase properties. GENERAL SIGNIFICANCE Our study provides a pragmatic approach for developing NM23-H2-targeting regulators to rescue NM23-H2 binding at structurally ambiguous Pu27-GQ that synergizes the anti-tumorigenic effects of GQ-based therapeutics with minimized off-target effects.
Collapse
Affiliation(s)
- Pallabi Sengupta
- Department of Biophysics, Bose Institute, Centenary Campus, P-1/12, C.I.T. Scheme VIIM, Kankurgachi, Kolkata 700054, India
| | - Subhrangsu Chatterjee
- Department of Biophysics, Bose Institute, Centenary Campus, P-1/12, C.I.T. Scheme VIIM, Kankurgachi, Kolkata 700054, India.
| |
Collapse
|
3
|
Yang Q, Lang C, Wu Z, Dai Y, He S, Guo W, Huang S, Du H, Ren D, Peng X. MAZ promotes prostate cancer bone metastasis through transcriptionally activating the KRas-dependent RalGEFs pathway. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:391. [PMID: 31488180 PMCID: PMC6729064 DOI: 10.1186/s13046-019-1374-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 08/09/2019] [Indexed: 01/22/2023]
Abstract
Background Clinically, prostate cancer (PCa) exhibits a high avidity to metastasize to bone. Myc-associated zinc-finger protein (MAZ) is a well-documented oncogene involved in the progression and metastasis of multiple cancer types, even in PCa. However, the clinical significance and biological roles of MAZ in bone metastasis of PCa remain unclear. Methods MAZ expression was examined in PCa tissues with bone metastasis, PCa tissues without bone metastasis and metastatic bone tissues by real-time PCR and immunohistochemistry (IHC), respectively. Statistical analysis was performed to evaluate the clinical correlation between MAZ expression and clinicopathological features and bone metastasis-free survival in PCa patients. Biological roles of MAZ in bone metastasis of PCa were investigated both in vitro by transwell assay, and in vivo by a mouse model of left cardiac ventricle inoculation. The bioinformatics analysis, western blot, pull-down assays, chromatin immunoprecipitation (ChIP) and luciferase reporter assays were applied to demonstrate and examine the relationship between MAZ and its potential downstream signalling pathway. TaqMan copy number assay was performed to identify the underlying mechanism responsible for MAZ overexpression in PCa tissues. Results MAZ expression is elevated in PCa tissues with bone metastasis compared with that in PCa tissues without bone metastasis, and is further increased in metastatic bone tissues. High expression of MAZ positively correlates with poor overall and bone metastasis-free survival in PCa patients. Upregulating MAZ elevates, while silencing MAZ represses the invasion and migration abilities of PCa cells in vitro and bone metastasis ability in vivo. Our results further reveal that MAZ promotes bone metastasis of PCa dependent on KRas signalling, although MAZ transcriptionally upregulates KRas and HRas expression, where the Ral guanine nucleotide exchange factor (RalGEF) signaling is responsible for the different roles of KRas and HRas in mediating the pro-bone metastasis of MAZ in PCa. Finally, our results indicate that recurrent gains contribute to MAZ overexpression in a small portion of PCa tissues. Conclusion These results indicate that the MAZ/Kras/ RalGEF signalling axis plays a crucial role in promoting PCa cell bone metastasis, suggesting a potential therapeutic utility of MAZ in bone metastasis of PCa. Electronic supplementary material The online version of this article (10.1186/s13046-019-1374-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Qing Yang
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, 58# Zhongshan 2rd Road, Guangzhou, 510080, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Guangzhou, 510080, Guangdong Province, China
| | - Chuandong Lang
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, 58# Zhongshan 2rd Road, Guangzhou, 510080, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Guangzhou, 510080, Guangdong Province, China
| | - Zhengquan Wu
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, 58# Zhongshan 2rd Road, Guangzhou, 510080, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Guangzhou, 510080, Guangdong Province, China
| | - Yuhu Dai
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, 58# Zhongshan 2rd Road, Guangzhou, 510080, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Guangzhou, 510080, Guangdong Province, China
| | - Shaofu He
- Department of Radiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510080, Guangdong Province, China
| | - Wei Guo
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, 58# Zhongshan 2rd Road, Guangzhou, 510080, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Guangzhou, 510080, Guangdong Province, China
| | - Shuai Huang
- Department of Orthopaedic Surgery, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, China
| | - Hong Du
- Department of Pathology, The First People's Hospital of Guangzhou City, Guangzhou, 510180, Guangdong, China
| | - Dong Ren
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, 58# Zhongshan 2rd Road, Guangzhou, 510080, Guangdong Province, China. .,Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Guangzhou, 510080, Guangdong Province, China.
| | - Xinsheng Peng
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, 58# Zhongshan 2rd Road, Guangzhou, 510080, Guangdong Province, China. .,Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Guangzhou, 510080, Guangdong Province, China.
| |
Collapse
|
4
|
Chen Y, Zeng Y, Xiao Z, Chen S, Li Y, Zou J, Zeng X. Role of heterogeneous nuclear ribonucleoprotein K in tumor development. J Cell Biochem 2019; 120:14296-14305. [PMID: 31127648 DOI: 10.1002/jcb.28867] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 12/11/2022]
Abstract
Heterogeneous nuclear ribonucleoprotein K (hnRNP K) is an RNA/DNA special binding protein that participates in regulating the expression of related genes, transcription, RNA alternative splicing, translation, posttranslational modification, cell signal transduction, cell movement, interacts with ncRNAs, and induces angiogenesis. Moreover, several cellular functions forcefully indicated that hnRNP K participates in tumorigenesis. Numerous studies indicated hnRNP K is aberrantly elevated in multiple tumors. In addition, hnRNP K abnormal accumulation in cytoplasmic is also associated with poor prognosis. This suggests that hnRNP K may play a role in the development and progression of tumors. However, related studies demonstrated that hnRNP K acts as a tumor suppressor to suppress tumor formation. Therefore, this paper aims to explore the role of hnRNPK in tumors.
Collapse
Affiliation(s)
- Yuting Chen
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, Hengyang School of Medicine, University of South China, Hengyang, China
| | - Ying Zeng
- School of Nursing, University of South China, Hengyang, China
| | - Zheng Xiao
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, Hengyang School of Medicine, University of South China, Hengyang, China
| | - Shi Chen
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, Hengyang School of Medicine, University of South China, Hengyang, China
| | - Yukun Li
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, Hengyang School of Medicine, University of South China, Hengyang, China
| | - Juan Zou
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, Hengyang School of Medicine, University of South China, Hengyang, China
| | - Xi Zeng
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, Hengyang School of Medicine, University of South China, Hengyang, China.,Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| |
Collapse
|
5
|
Geltinger C, Hörtnagel K, Polack A. TATA box and Sp1 sites mediate the activation of c-myc promoter P1 by immunoglobulin kappa enhancers. Gene Expr 2018; 6:113-27. [PMID: 8979089 PMCID: PMC6148303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In Burkitt's lymphoma (BL) cells the proto-oncogene c-myc is transcriptionally activated by chromosomal translocation to the immunoglobulin (Ig) gene loci. This activation is characterized by preferential transcription from the c-myc promoter P1 and accomplished by juxtaposed Ig enhancer elements. To identify promoter elements required for enhancer-activated P1 transcription, we studied the activation of c-myc reporter gene constructs by the Ig kappa intron and 3' enhancers. Deletion analysis defined the core promoter with a TATA box and two adjacent GC/GT boxes upstream sufficient for basal and enhancer-activated transcription. Gel retardation assays revealed Sp1's binding affinity to the GC/GT box proximal to the TATA box to be higher than to the distal one. This difference correlated well with the resulting levels of transcription mediated by Sp1 in contransfection experiments in BL and Sp1-deficient SL2 cells. Sp3 also bound to the core promoter in vitro, but failed to transactivate in vivo. Mutation of the distal Sp1 site moderately affected basal transcription concomitant with a modest decrease in enhancer stimulation. Mutation of the proximal Sp1 site almost entirely abolished basal as well as enhanced transcription. A considerable level of basal transcription was maintained upon mutation of the TATA box, whereas enhancer-activated transcription largely was abolished. Stable transfection of the BL cell line Raji with constructs containing core promoter mutations confirmed that the proximal Sp1 site and the TATA box are essential for the activation of promoter P1 by the Ig kappa enhancers.
Collapse
Affiliation(s)
- C Geltinger
- GSF-National Research Center for Environment and Health, Institute of Clinical Molecular Biology and Tumour Genetics, München, Germany
| | | | | |
Collapse
|
6
|
Bardales JA, Wieser E, Kawaji H, Murakawa Y, Darzacq X. Selective Activation of Alternative MYC Core Promoters by Wnt-Responsive Enhancers. Genes (Basel) 2018; 9:genes9060270. [PMID: 29882899 PMCID: PMC6027352 DOI: 10.3390/genes9060270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/14/2018] [Accepted: 05/15/2018] [Indexed: 11/16/2022] Open
Abstract
In Metazoans, transcription of most genes is driven by the use of multiple alternative promoters. Although the precise regulation of alternative promoters is important for proper gene expression, the mechanisms that mediates their differential utilization remains unclear. Here, we investigate how the two alternative promoters (P1, P2) that drive MYC expression are regulated. We find that P1 and P2 can be differentially regulated across cell-types and that their selective usage is largely mediated by distal regulatory sequences. Moreover, we show that in colon carcinoma cells, Wnt-responsive enhancers preferentially upregulate transcription from the P1 promoter using reporter assays and in the context of the endogenous Wnt induction. In addition, multiple enhancer deletions using CRISPR/Cas9 corroborate the regulatory specificity of P1. Finally, we show that preferential activation between Wnt-responsive enhancers and the P1 promoter is influenced by the distinct core promoter elements that are present in the MYC promoters. Taken together, our results provide new insight into how enhancers can specifically target alternative promoters and suggest that formation of these selective interactions could allow more precise combinatorial regulation of transcription initiation.
Collapse
Affiliation(s)
- Jorge A Bardales
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA.
| | - Evin Wieser
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
| | - Hideya Kawaji
- Division of Genomic Technologies, RIKEN Center for Life Science Technologies, Yokohama 230-0045, Japan.
- RIKEN Preventive Medicine and Diagnosis Innovation Program, Yokohama 230-0045, Japan.
- Preventive Medicine and Applied Genomics Unit, RIKEN Advanced Center for Computing and Communication, Yokohama 230-0045, Japan.
| | - Yasuhiro Murakawa
- Division of Genomic Technologies, RIKEN Center for Life Science Technologies, Yokohama 230-0045, Japan.
- RIKEN Preventive Medicine and Diagnosis Innovation Program, Yokohama 230-0045, Japan.
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
- Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley, CA 94720, USA.
| |
Collapse
|
7
|
Liu HY, Chen AC, Yin QK, Li Z, Huang SM, Du G, He JH, Zan LP, Wang SK, Xu YH, Tan JH, Ou TM, Li D, Gu LQ, Huang ZS. New Disubstituted Quindoline Derivatives Inhibiting Burkitt's Lymphoma Cell Proliferation by Impeding c-MYC Transcription. J Med Chem 2017; 60:5438-5454. [PMID: 28603988 DOI: 10.1021/acs.jmedchem.7b00099] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The c-MYC oncogene is overactivated during Burkitt's lymphoma pathogenesis. Targeting c-MYC to inhibit its transcriptional activity has emerged as an effective anticancer strategy. We synthesized four series of disubstituted quindoline derivatives by introducing the second cationic amino side chain and 5-N-methyl group based on a previous study of SYUIQ-5 (1) as c-MYC promoter G-quadruplex ligands. The in vitro evaluations showed that all new compounds exhibited higher stabilities and binding affinities, and most of them had better selectivity (over duplex DNA) for the c-MYC G-quadruplex compared to 1. Moreover, the new ligands prevented NM23-H2, a transcription factor, from effectively binding to the c-MYC G-quadruplex. Further studies showed that the selected ligand, 7a4, down-regulated c-MYC transcription by targeting promoter G-quadruplex and disrupting the NM23-H2/c-MYC interaction in RAJI cells. 7a4 could inhibit Burkitt's lymphoma cell proliferation through cell cycle arrest and apoptosis and suppress tumor growth in a human Burkitt's lymphoma xenograft.
Collapse
Affiliation(s)
- Hui-Yun Liu
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Ai-Chun Chen
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Qi-Kun Yin
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Zeng Li
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Su-Mei Huang
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Gang Du
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Jin-Hui He
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Li-Peng Zan
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Shi-Ke Wang
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Yao-Hao Xu
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Jia-Heng Tan
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Tian-Miao Ou
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Ding Li
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Lian-Quan Gu
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| | - Zhi-Shu Huang
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, People's Republic of China
| |
Collapse
|
8
|
Sutherland C, Cui Y, Mao H, Hurley LH. A Mechanosensor Mechanism Controls the G-Quadruplex/i-Motif Molecular Switch in the MYC Promoter NHE III1. J Am Chem Soc 2016; 138:14138-14151. [DOI: 10.1021/jacs.6b09196] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Caleb Sutherland
- University of Arizona Cancer Center, 1515 North Campbell Avenue, Tucson, Arizona 85724, United States
| | - Yunxi Cui
- Department
of Chemistry and Biochemistry and School of Biomedical Sciences, Kent State University, Kent, Ohio 44242, United States
| | - Hanbin Mao
- Department
of Chemistry and Biochemistry and School of Biomedical Sciences, Kent State University, Kent, Ohio 44242, United States
| | - Laurence H. Hurley
- University of Arizona Cancer Center, 1515 North Campbell Avenue, Tucson, Arizona 85724, United States
- University of Arizona, College of Pharmacy, 1703 East Mabel Street, Tucson, Arizona 85721, United States
- BIO5 Institute, 1657 East
Helen Street, Tucson, Arizona 85721, United States
| |
Collapse
|
9
|
Nuclear AURKA acquires kinase-independent transactivating function to enhance breast cancer stem cell phenotype. Nat Commun 2016; 7:10180. [PMID: 26782714 PMCID: PMC4735655 DOI: 10.1038/ncomms10180] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 11/12/2015] [Indexed: 12/26/2022] Open
Abstract
Centrosome-localized mitotic Aurora kinase A (AURKA) facilitates G2/M events. Here we show that AURKA translocates to the nucleus and causes distinct oncogenic properties in malignant cells by enhancing breast cancer stem cell (BCSC) phenotype. Unexpectedly, this function is independent of its kinase activity. Instead, AURKA preferentially interacts with heterogeneous nuclear ribonucleoprotein K (hnRNP K) in the nucleus and acts as a transcription factor in a complex that induces a shift in MYC promoter usage and activates the MYC promoter. Blocking AURKA nuclear localization inhibits this newly discovered transactivating function of AURKA, sensitizing resistant BCSC to kinase inhibition. These findings identify a previously unknown oncogenic property of the spatially deregulated AURKA in tumorigenesis and provide a potential therapeutic opportunity to overcome kinase inhibitor resistance.
Collapse
|
10
|
Liu N, Liu X, Zhou N, Wu Q, Zhou L, Li Q. Gene expression profiling and bioinformatics analysis of gastric carcinoma. Exp Mol Pathol 2014; 96:361-6. [PMID: 24589858 DOI: 10.1016/j.yexmp.2014.02.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 02/21/2014] [Indexed: 12/12/2022]
Abstract
Gastric cancer remains one of the major health problems worldwide, and it is one of the most common cancers and the leading cause of cancer-related deaths in China. This study was to analyze the expression profiles of genes in gastric carcinoma, and predict potential regulating factors. The gene expression profile data GSE13911 was downloaded from Gene Expression Omnibus and the differentially expressed genes (DEGs) were identified by t-test. Gene modules were constructed using hierarchical clustering in R based on average linkage and Pearson's correlation coefficient and functional analysis for these genes were performed with DAVID. Genes in each module with Pearson's correlation coefficient >0.3 were obtained to construct co-expression network. Protein-protein interactions (PPIs) were identified by comparing protein-protein interaction (PPI) network with co-expression networks. In addition, the potential regulatory microRNAs and the transcription factors for each module were screened out. In this study, six modules associated with protein degradation, cell cycle, protein trafficking and immunoreaction were identified. COPS5 (COP9 Subunit 5) was the core protein in the largest PPI network of module 1. The transcription factors MYC and MAZ (Myc-associated zinc-finger protein) were enriched in module 1. A total of 9 microRNA-target bi-clusters were identified and module 1 enriched 20 genes targeting to miR-17-92 gene cluster(miR-17/20ab)and miR-106b-25 gene cluster (miR-106b/93). In conclusion, we constructed 6 gene modules and screened out some genes, transcriptional factors and microRNAs that may be used as potential molecular biomarkers for gastric carcinoma.
Collapse
Affiliation(s)
- Ningning Liu
- Department of Medical Oncology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China; Interventional Cancer Institute of Integrative Medicine & Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, PR China
| | - Xuan Liu
- Department of Medical Oncology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China
| | - Ning Zhou
- Interventional Cancer Institute of Integrative Medicine & Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, PR China
| | - Qiong Wu
- Interventional Cancer Institute of Integrative Medicine & Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, PR China
| | - Lihong Zhou
- Department of Medical Oncology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China
| | - Qi Li
- Department of Medical Oncology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China.
| |
Collapse
|
11
|
Jeong W, Lim W, Ahn SE, Lim CH, Lee JY, Bae SM, Kim J, Bazer FW, Song G. Recrudescence mechanisms and gene expression profile of the reproductive tracts from chickens during the molting period. PLoS One 2013; 8:e76784. [PMID: 24098561 PMCID: PMC3788108 DOI: 10.1371/journal.pone.0076784] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/03/2013] [Indexed: 02/04/2023] Open
Abstract
The reproductive system of chickens undergoes dynamic morphological and functional tissue remodeling during the molting period. The present study identified global gene expression profiles following oviductal tissue regression and regeneration in laying hens in which molting was induced by feeding high levels of zinc in the diet. During the molting and recrudescence processes, progressive morphological and physiological changes included regression and re-growth of reproductive organs and fluctuations in concentrations of testosterone, progesterone, estradiol and corticosterone in blood. The cDNA microarray analysis of oviductal tissues revealed the biological significance of gene expression-based modulation in oviductal tissue during its remodeling. Based on the gene expression profiles, expression patterns of selected genes such as, TF, ANGPTL3, p20K, PTN, AvBD11 and SERPINB3 exhibited similar patterns in expression with gradual decreases during regression of the oviduct and sequential increases during resurrection of the functional oviduct. Also, miR-1689* inhibited expression of Sp1, while miR-17-3p, miR-22* and miR-1764 inhibited expression of STAT1. Similarly, chicken miR-1562 and miR-138 reduced the expression of ANGPTL3 and p20K, respectively. These results suggest that these differentially regulated genes are closely correlated with the molecular mechanism(s) for development and tissue remodeling of the avian female reproductive tract, and that miRNA-mediated regulation of key genes likely contributes to remodeling of the avian reproductive tract by controlling expression of those genes post-transcriptionally. The discovered global gene profiles provide new molecular candidates responsible for regulating morphological and functional recrudescence of the avian reproductive tract, and provide novel insights into understanding the remodeling process at the genomic and epigenomic levels.
Collapse
Affiliation(s)
- Wooyoung Jeong
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Whasun Lim
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Suzie E. Ahn
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Chul-Hong Lim
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Jin-Young Lee
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Seung-Min Bae
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Jinyoung Kim
- Department of Animal Resources Science, Dankook University, Cheonan, Republic of Korea
| | - Fuller W. Bazer
- Center for Animal Biotechnology and Genomics and Department of Animal Science, Texas A&M University, College Station, Texas, United States of America
| | - Gwonhwa Song
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| |
Collapse
|
12
|
Song HK, Hong SE, Kim T, Kim DH. Deep RNA sequencing reveals novel cardiac transcriptomic signatures for physiological and pathological hypertrophy. PLoS One 2012; 7:e35552. [PMID: 22523601 PMCID: PMC3327670 DOI: 10.1371/journal.pone.0035552] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2011] [Accepted: 03/21/2012] [Indexed: 12/25/2022] Open
Abstract
Although both physiological hypertrophy (PHH) and pathological hypertrophy (PAH) of the heart have similar morphological appearances, only PAH leads to fatal heart failure. In the present study, we used RNA sequencing (RNA-Seq) to determine the transcriptomic signatures for both PHH and PAH. Approximately 13-20 million reads were obtained for both models, among which PAH showed more differentially expressed genes (DEGs) (2,041) than PHH (245). The expression of 417 genes was barely detectable in the normal heart but was suddenly activated in PAH. Among them, Foxm1 and Plk1 are of particular interest, since Ingenuity Pathway Analysis (IPA) using DEGs and upstream motif analysis showed that they are essential hub proteins that regulate the expression of downstream proteins associated with PAH. Meanwhile, 52 genes related to collagen, chemokines, and actin showed opposite expression patterns between PHH and PAH. MAZ-binding motifs were enriched in the upstream region of the participating genes. Alternative splicing (AS) of exon variants was also examined using RNA-Seq data for PAH and PHH. We found 317 and 196 exon inclusions and exon exclusions, respectively, for PAH, and 242 and 172 exon inclusions and exclusions, respectively for PHH. The AS pattern was mostly related to gains or losses of domains, changes in activity, and localization of the encoded proteins. The splicing variants of 8 genes (i.e., Fhl1, Rcan1, Ndrg2, Synpo, Ttll1, Cxxc5, Egfl7, and Tmpo) were experimentally confirmed. Multilateral pathway analysis showed that the patterns of quantitative (DEG) and qualitative (AS) changes differ depending on the type of pathway in PAH and PHH. One of the most significant changes in PHH is the severe downregulation of autoimmune pathways accompanied by significant AS. These findings revealed the unique transcriptomic signatures of PAH and PHH and also provided a more comprehensive understanding at both the quantitative and qualitative levels.
Collapse
Affiliation(s)
| | | | | | - Do Han Kim
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| |
Collapse
|
13
|
Lin PY, Lin YL, Huang CC, Chen SS, Liu YW. Inorganic arsenic in drinking water accelerates N-butyl-N-(4-hydroxybutyl)nitrosamine-induced bladder tissue damage in mice. Toxicol Appl Pharmacol 2011; 259:27-37. [PMID: 22178741 DOI: 10.1016/j.taap.2011.11.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 11/23/2011] [Accepted: 11/25/2011] [Indexed: 10/14/2022]
Abstract
Epidemiological studies have revealed that exposure to an arsenic-contaminated environment correlates with the incidence of bladder cancer. Bladder cancer is highly recurrent after intravesical therapy, and most of the deaths from this disease are due to invasive metastasis. In our present study, the role of inorganic arsenic in bladder carcinogenesis is characterized in a mouse model. This work provides the first evidence that inorganic arsenic in drinking water promotes N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-induced bladder tissue damage, including the urothelium and submucosal layer. This damage to the bladder epithelium induced by BBN includes thickening of the submucosal layer, the loss of the glycosaminoglycan layer and an increase in both the deoxyguanosine oxidation and cytosine methylation levels in the DNA. Further, when 10ppm inorganic arsenic is combined with BBN, the number of bladder submucosal capillaries is increased. In addition, inorganic arsenic also increases the deoxyguanosine oxidation level, alters the cytosine methylation state, decreases the activities of glutathione reductase and glucose-6-phosphate dehydrogenase, decreases the protein expression of NAD(P)H quinone oxidoreductase-1 (NQO-1) and increases the protein expression of specific protein 1 (Sp1) in bladder tissues. In summary, our data reveal that inorganic arsenic in drinking water promotes the BBN-induced pre-neoplastic damage of bladder tissue in mice, and that the 8-hydroxy-2'-deoxyguanosine, 5-methylcytosine, NQO-1 protein and Sp1 protein levels may be pre-neoplastic markers of bladder tumors.
Collapse
Affiliation(s)
- Paul-Yann Lin
- Department of Pathology, Chang Gung Memorial Hospital at Chiayi, Chang Gung University, Chiayi, Taiwan
| | | | | | | | | |
Collapse
|
14
|
Wang C, Mayer JA, Mazumdar A, Fertuck K, Kim H, Brown M, Brown PH. Estrogen induces c-myc gene expression via an upstream enhancer activated by the estrogen receptor and the AP-1 transcription factor. Mol Endocrinol 2011; 25:1527-38. [PMID: 21835891 DOI: 10.1210/me.2011-1037] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
c-myc oncogene is implicated in tumorigenesis of many cancers, including breast cancer. Although c-myc is a well-known estrogen-induced gene, its promoter has no estrogen-response element, and the underlying mechanism by which estrogen induces its expression remains obscure. Recent genome-wide studies by us and others suggested that distant elements may mediate estrogen induction of gene expression. In this study, we investigated the molecular mechanism by which estrogen induces c-myc expression with a focus on these distal elements. Estrogen rapidly induced c-myc expression in estrogen receptor (ER)-positive breast cancer cells. Although estrogen had little effect on c-myc proximal promoter activity, it did stimulate the activity of a luciferase reporter containing a distal 67-kb enhancer. Estrogen induction of this luciferase reporter was dependent upon both a half-estrogen response element and an activator protein 1 (AP-1) site within this enhancer, which are conserved across 11 different mammalian species. Small interfering RNA experiments and chromatin immunoprecipitation assays demonstrated the necessity of ER and AP-1 cross talk for estrogen to induce c-myc expression. TAM67, the AP-1 dominant negative, partially inhibited estrogen induction of c-myc expression and suppressed estrogen-induced cell cycle progression. Together, these results demonstrate a novel pathway of estrogen regulation of gene expression by cooperation between ER and AP-1 at the distal enhancer element and that AP-1 is involved in estrogen induction of the c-myc oncogene. These results solve the long-standing question in the field of endocrinology of how estrogen induces c-myc expression.
Collapse
Affiliation(s)
- Chunyu Wang
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | | | | | | | | | | | | |
Collapse
|
15
|
Li L, Davie JR. The role of Sp1 and Sp3 in normal and cancer cell biology. Ann Anat 2010; 192:275-83. [PMID: 20810260 DOI: 10.1016/j.aanat.2010.07.010] [Citation(s) in RCA: 443] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 07/22/2010] [Indexed: 10/19/2022]
Abstract
Sp1 and Sp3 are transcription factors expressed in all mammalian cells. These factors are involved in regulating the transcriptional activity of genes implicated in most cellular processes. Dysregulation of Sp1 and Sp3 is observed in many cancers and diseases. Due to the amino acid sequence similarity of the DNA binding domains, Sp1 and Sp3 recognize and associate with the same DNA element with similar affinity. However, others and our laboratory demonstrated that these two factors possess different properties and exert different functional roles. Both Sp1 and Sp3 can interact with and recruit a large number of proteins including the transcription initiation complex, histone modifying enzymes and chromatin remodeling complexes, which strongly suggest that Sp1 and Sp3 are important transcription factors in the remodeling chromatin and the regulation of gene expression. In this review, the role of Sp1 and Sp3 in normal and cancer cell biology and the multiple mechanisms deciding the functional roles of Sp1 and Sp3 will be presented.
Collapse
Affiliation(s)
- Lin Li
- Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Manitoba R3E 0V9, Canada
| | | |
Collapse
|
16
|
Hsin IL, Sheu GT, Chen HH, Chiu LY, Wang HD, Chan HW, Hsu CP, Ko JL. N-acetyl cysteine mitigates curcumin-mediated telomerase inhibition through rescuing of Sp1 reduction in A549 cells. Mutat Res 2010; 688:72-77. [PMID: 20363232 DOI: 10.1016/j.mrfmmm.2010.03.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 03/14/2010] [Accepted: 03/15/2010] [Indexed: 05/29/2023]
Abstract
Curcumin is a natural compound that has been extensively observed due to its potential as an anticancer drug. Curcumin restrains cancer cell progression via telomerase activity suppression. However, the exact mechanism is still unknown. In this study, we demonstrate that the effects of curcumin on cell viability and telomerase activity can be blunted by reactive oxygen species (ROS) inhibitor N-acetyl cysteine (NAC). The ROS induced by curcumin in A549 cells was detected by flow cytometry. Using Western blot and RT-PCR, human telomerase reverse transcriptase (hTERT) decreased in the presence of curcumin. Sp1 is one of the important transcription factors in hTERT expression. Our data showed that curcumin decreases the expression of Sp1 through proteasome pathway. In addition, NAC blunted the Sp1 reduction and hTERT downregulation by curcumin. Further, reporter assay and DNA affinity precipitation assay confirmed the influence of curcumin on Sp1 in hTERT regulation. This is the first study to demonstrate that curcumin induces ROS production resulting in Sp1 binding activity inhibition and hTERT downregulation.
Collapse
Affiliation(s)
- I-Lun Hsin
- Institute of Medical and Molecular Toxicology, Chung Shan Medical University, Taichung, Taiwan, ROC
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Cellular nucleic-acid-binding protein, a transcriptional enhancer of c-Myc, promotes the formation of parallel G-quadruplexes. Biochem J 2010; 428:491-8. [DOI: 10.1042/bj20100038] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
G-rich sequences that contain stretches of tandem guanines can form four-stranded, intramolecular stable DNA structures called G-quadruplexes (termed G4s). Regulation of the equilibrium between single-stranded and G4 DNA in promoter regions is essential for control of gene expression in the cell. G4s are highly stable structures; however, their folding kinetics are slow under physiological conditions. CNBP (cellular nucleic-acid-binding protein) is a nucleic acid chaperone that binds the G4-forming G-rich sequence located within the NHE (nuclease hypersensitivity element) III of the c-Myc proto-oncogene promoter. Several reports have demonstrated that CNBP enhances the transcription of c-Myc in vitro and in vivo; however, none of these reports have assessed the molecular mechanisms responsible for this control. In the present study, by means of Taq polymerase stop assays, electrophoretic mobility-shift assays and CD spectroscopy, we show that CNBP promotes the formation of parallel G4s to the detriment of anti-parallel G4s, and its nucleic acid chaperone activity is required for this effect. These findings are the first to implicate CNBP as a G4-folding modulator and, furthermore, assign CNBP a novel mode-of-action during c-Myc transcriptional regulation.
Collapse
|
18
|
Abstract
c-MYC is an important regulator of a wide array of cellular processes necessary for normal cell growth and differentiation, and its dysregulation is one of the hallmarks of many cancers. Consequently, understanding c-MYC transcriptional activation is critical for understanding developmental and cancer biology, as well as for the development of new anticancer drugs. The nuclease hypersensitive element (NHE) III(1) region of the c-MYC promoter has been shown to be particularly important in regulating c-MYC expression. Specifically, the formation of a G-quadruplex structure appears to promote repression of c-MYC transcription. This review focuses on what is known about the formation of a G-quadruplex in the NHE III(1) region of the c-MYC promoter, as well as on those factors that are known to modulate its formation. Last, we discuss the development of small molecules that stabilize or induce the formation of G-quadruplex structures and could potentially be used as anticancer agents.
Collapse
|
19
|
Yang L, He J, Chen L, Wang G. Hepatitis B virus X protein upregulates expression of SMYD3 and C-MYC in HepG2 cells. Med Oncol 2008; 26:445-51. [PMID: 19082926 DOI: 10.1007/s12032-008-9144-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Accepted: 11/21/2008] [Indexed: 01/11/2023]
Abstract
The carcinogenic role of Hepatitis B X (HBX) in hepatocellular carcinoma (HCC) remains largely unknown. Histone H3 lysine 4 methyltransferase SMYD3 was found to be over-expressed and have a pro-carcinogenic effect in HCC. The role of HBX in regulating SMYD3 activity and the corresponding C-MYC gene in HCC carcinogenesis was investigated. SMYD3 and C-MYC expression in HBV-negative HepG2 and HBV-positive HepG2.2.15 were detected by real time PCR and Western blot. After transfection of HBX into HepG2, SMYD3 and C-MYC protein expression was detected and the apoptosis and proliferation of hepatoma cells were assayed. After SMYD3 expression in HepG2 with HBX transfection downregulated by siRNA, the corresponding C-MYC expression, cellular apoptosis, and proliferation were assayed by FACS. SMYD3 mRNA and protein and C-MYC protein were significantly higher in HepG2.2.15 than in HepG2. HBX transfection resulted in enhanced SMYD3 and C-MYC expressions, decreased cell apoptosis, and increased cell proliferation in HepG2 cells. Knocking down of SMYD3 in HepG2 with HBX transfection inhibited C-MYC expression and promoted apoptosis. These results suggest that HBX upregulates SMYD3 expression in HepG2, which may promote hepatoma development and progress. C-MYC may act as a down-stream gene in HBX-SMYD3-related hepatocarcinogenesis.
Collapse
Affiliation(s)
- Lian Yang
- Hepatobiliary Center, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Jiefang Dadao 1277, Wuhan 430022, People's Republic of China
| | | | | | | |
Collapse
|
20
|
Armas P, Nasif S, Calcaterra NB. Cellular nucleic acid binding protein binds G-rich single-stranded nucleic acids and may function as a nucleic acid chaperone. J Cell Biochem 2008; 103:1013-36. [PMID: 17661353 DOI: 10.1002/jcb.21474] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cellular nucleic acid binding protein (CNBP) is a small single-stranded nucleic acid binding protein made of seven Zn knuckles and an Arg-Gly rich box. CNBP is strikingly conserved among vertebrates and was reported to play broad-spectrum functions in eukaryotic cells biology. Neither its biological function nor its mechanisms of action were elucidated yet. The main goal of this work was to gain further insights into the CNBP biochemical and molecular features. We studied Bufo arenarum CNBP (bCNBP) binding to single-stranded nucleic acid probes representing the main reported CNBP putative targets. We report that, although bCNBP is able to bind RNA and single-stranded DNA (ssDNA) probes in vitro, it binds RNA as a preformed dimer whereas both monomer and dimer are able to bind to ssDNA. A systematic analysis of variant probes shows that the preferred bCNBP targets contain unpaired guanosine-rich stretches. These data expand the knowledge about CNBP binding stoichiometry and begins to dissect the main features of CNBP nucleic acid targets. Besides, we show that bCNBP presents a highly disordered predicted structure and promotes the annealing and melting of nucleic acids in vitro. These features are typical of proteins that function as nucleic acid chaperones. Based on these data, we propose that CNBP may function as a nucleic acid chaperone through binding, remodeling, and stabilizing nucleic acids secondary structures. This novel CNBP biochemical activity broadens the field of study about its biological function and may be the basis to understand the diverse ways in which CNBP controls gene expression.
Collapse
Affiliation(s)
- Pablo Armas
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Dpto. de Ciencias Biológicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Argentina
| | | | | |
Collapse
|
21
|
Marampon F, Casimiro MC, Fu M, Powell MJ, Popov VM, Lindsay J, Zani BM, Ciccarelli C, Watanabe G, Lee RJ, Pestell RG. Nerve Growth factor regulation of cyclin D1 in PC12 cells through a p21RAS extracellular signal-regulated kinase pathway requires cooperative interactions between Sp1 and nuclear factor-kappaB. Mol Biol Cell 2008; 19:2566-78. [PMID: 18367547 DOI: 10.1091/mbc.e06-12-1110] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The PC12 pheochromocytoma cell line responds to nerve growth factor (NGF) by exiting from the cell cycle and differentiating to induce extending neurites. Cyclin D1 is an important regulator of G1/S phase cell cycle progression, and it is known to play a role in myocyte differentiation in cultured cells. Herein, NGF induced cyclin D1 promoter, mRNA, and protein expression via the p21(RAS) pathway. Antisense- or small interfering RNA to cyclin D1 abolished NGF-mediated neurite outgrowth, demonstrating the essential role of cyclin D1 in NGF-mediated differentiation. Expression vectors encoding mutants of the Ras/mitogen-activated protein kinase pathway, and chemical inhibitors, demonstrated NGF induction of cyclin D1 involved cooperative interactions of extracellular signal-regulated kinase, p38, and phosphatidylinositol 3-kinase pathways downstream of p21(RAS). NGF induced the cyclin D1 promoter via Sp1, nuclear factor-kappaB, and cAMP-response element/activated transcription factor sites. NGF induction via Sp1 involved the formation of a Sp1/p50/p107 complex. Cyclin D1 induction by NGF governs differentiation and neurite outgrowth in PC12 cells.
Collapse
Affiliation(s)
- Francesco Marampon
- Department of Cancer Biology and Medical Oncology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Wierstra I. Sp1: emerging roles--beyond constitutive activation of TATA-less housekeeping genes. Biochem Biophys Res Commun 2008; 372:1-13. [PMID: 18364237 DOI: 10.1016/j.bbrc.2008.03.074] [Citation(s) in RCA: 275] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 03/17/2008] [Indexed: 01/21/2023]
|
23
|
Palumbo SL, Memmott RM, Uribe DJ, Krotova-Khan Y, Hurley LH, Ebbinghaus SW. A novel G-quadruplex-forming GGA repeat region in the c-myb promoter is a critical regulator of promoter activity. Nucleic Acids Res 2008; 36:1755-69. [PMID: 18252774 PMCID: PMC2330228 DOI: 10.1093/nar/gkm1069] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The c-myb promoter contains multiple GGA repeats beginning 17 bp downstream of the transcription initiation site. GGA repeats have been previously shown to form unusual DNA structures in solution. Results from chemical footprinting, circular dichroism and RNA and DNA polymerase arrest assays on oligonucleotides representing the GGA repeat region of the c-myb promoter demonstrate that the element is able to form tetrad:heptad:heptad:tetrad (T:H:H:T) G-quadruplex structures by stacking two tetrad:heptad G-quadruplexes formed by two of the three (GGA)(4) repeats. Deletion of one or two (GGA)(4) motifs destabilizes this secondary structure and increases c-myb promoter activity, indicating that the G-quadruplexes formed in the c-myb GGA repeat region may act as a negative regulator of the c-myb promoter. Complete deletion of the c-myb GGA repeat region abolishes c-myb promoter activity, indicating dual roles of the c-myb GGA repeat element as both a transcriptional repressor and an activator. Furthermore, we demonstrated that Myc-associated zinc finger protein (MAZ) represses c-myb promoter activity and binds to the c-myb T:H:H:T G-quadruplexes. Our findings show that the T:H:H:T G-quadruplex-forming region in the c-myb promoter is a critical cis-acting element and may repress c-myb promoter activity through MAZ interaction with G-quadruplexes in the c-myb promoter.
Collapse
Affiliation(s)
- SunMi L Palumbo
- Arizona Cancer Center, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ 85724-5024, USA
| | | | | | | | | | | |
Collapse
|
24
|
|
25
|
Wierstra I, Alves J. FOXM1c and Sp1 transactivate the P1 and P2 promoters of human c-myc synergistically. Biochem Biophys Res Commun 2007; 352:61-8. [PMID: 17141659 DOI: 10.1016/j.bbrc.2006.10.151] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Accepted: 10/26/2006] [Indexed: 12/31/2022]
Abstract
We have previously shown that FOXM1c transactivates the c-myc P1 and P2 promoters via their TATA-boxes by a new transactivation mechanism, namely by directly binding to the P1 and P2 TATA-boxes and to TBP, TFIIA, and TFIIB. We now confirm this surprising mechanism by demonstrating that FOXM1c transactivates the human c-myc P1 and P2 promoters synergistically with Sp1, a transcription factor known to bind and transactivate these two promoters. This synergism requires the P1 or P2 TATA-boxes as well as the respective Sp1-binding sites. Moreover FOXM1c binds directly to Sp1. Cooperative DNA binding, if it should occur, is not sufficient for synergism of Sp1 and FOXM1c at P1, but their contacts to multiple components of the basal transcription complex (TFIID, TFIIA, TFIIB) seem to be essential. However, FOXM1c does not synergize with Sp1 if it transactivates via its conventional binding site.
Collapse
Affiliation(s)
- Inken Wierstra
- Institute of Molecular Biology, Medical School Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
| | | |
Collapse
|
26
|
Muñoz E, Brewer M, Baler R. Modulation of BMAL/CLOCK/E-Box complex activity by a CT-rich cis-acting element. Mol Cell Endocrinol 2006; 252:74-81. [PMID: 16650525 DOI: 10.1016/j.mce.2006.03.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The interaction between the BMAL1/CLOCK transcription factor and the cis-acting element known as the E-Box is a key event in the regulation of clock and clock-controlled gene expression. However, the fact that the ubiquitous E-Box element sits at the center of a presumably highly discriminating control system generates a certain level of puzzlement. Widely spread E-Boxes with a generic sequence CANNTG have been associated with expression of genes involved in a host of disparate biological processes, including the orchestration of circadian physiology. The intriguing specificity of this short DNA consensus element begs the hypothesis that its actual circadian properties might be encoded elsewhere, e.g., other factors or adjacent sequences. In a previous study, we found evidence that a short sequence in the mouse arginine vasopressin (AVP) proximal promoter has the ability to confer robust BMAL1/CLOCK responsiveness onto an adjacent E-Box. Here, we report the systematic analysis of this element. Our findings further define the determining features and sequence boundaries of this element, establish the effect of the photoperiod upon its interacting protein(s), and suggest that its cognate binding activity might be modulated by Zn2+ in a peripheral oscillator.
Collapse
Affiliation(s)
- Estela Muñoz
- Unit on Temporal Gene Expression, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, United States
| | | | | |
Collapse
|
27
|
Liu J, Kouzine F, Nie Z, Chung HJ, Elisha-Feil Z, Weber A, Zhao K, Levens D. The FUSE/FBP/FIR/TFIIH system is a molecular machine programming a pulse of c-myc expression. EMBO J 2006; 25:2119-30. [PMID: 16628215 PMCID: PMC1462968 DOI: 10.1038/sj.emboj.7601101] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2005] [Accepted: 03/20/2006] [Indexed: 11/08/2022] Open
Abstract
FarUpStream Element (FUSE) Binding Protein (FBP) binds the human c-myc FUSE in vitro only in single-stranded or supercoiled DNA. Because transcriptionally generated torsion melts FUSE in vitro even in linear DNA, and FBP/FBP Interacting Repressor (FIR) regulates transcription through TFIIH, these components have been speculated to be the mechanosensor (FUSE) and effectors (FBP/FIR) of a real-time mechanism controlling c-myc transcription. To ascertain whether the FUSE/FBP/FIR system operates according to this hypothesis in vivo, the flux of activators, repressors and chromatin remodeling complexes on the c-myc promoter was monitored throughout the serum-induced pulse of transcription. After transcription was switched on by conventional factors and chromatin regulators, FBP and FIR were recruited and established a dynamically remodeled loop with TFIIH at the P2 promoter. In XPB cells carrying mutant TFIIH, loop formation failed and the serum response was abnormal; RNAi depletion of FIR similarly disabled c-myc regulation. Engineering FUSE into episomal vectors predictably re-programmed metallothionein-promoter-driven reporter expression. The in vitro recruitment of FBP and FIR to dynamically stressed c-myc DNA paralleled the in vivo process.
Collapse
Affiliation(s)
- Juhong Liu
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD, USA
| | - Fedor Kouzine
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD, USA
| | - Zuqin Nie
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD, USA
| | - Hye-Jung Chung
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD, USA
| | | | - Achim Weber
- Institute of Pathology, University of Mainz, Mainz, Germany
| | - Keji Zhao
- Laboratory of Molecular Immunology, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - David Levens
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD, USA
- Laboratory of Pathology, National Cancer Institute, Building 10, Room 2N106, NCI, CCR, Bethesda, MD 20892-1500, USA. Tel.: +1 301 496 2176; Fax: +1 301 594 5227; E-mail:
| |
Collapse
|
28
|
Abstract
Myc regulates to some degree every major process in the cell. Proliferation, growth, differentiation, apoptosis, and metabolism are all under myc control. In turn, these processes feed back to adjust the level of c-myc expression. Although Myc is regulated at every level from RNA synthesis to protein degradation, c-myc transcription is particularly responsive to multiple diverse physiological and pathological signals. These signals are delivered to the c-myc promoter by a wide variety of transcription factors and chromatin remodeling complexes. How these diverse and sometimes disparate signals are processed to manage the output of the c-myc promoter involves chromatin, recruitment of the transcription machinery, post-initiation transcriptional regulation, and mechanisms to provide dynamic feedback. Understanding these mechanisms promises to add new dimensions to models of transcriptional control and to reveal new strategies to manipulate Myc levels.
Collapse
Affiliation(s)
- J Liu
- Gene Regulation Section, Laboratory of Pathology, NCI, DCS, Bldg. 10, Rm 2N106, Bethesda, MD 20892-1500, USA
| | | |
Collapse
|
29
|
Nagai MA, Da Rós N, Neto MM, de Faria Junior SR, Brentani MM, Hirata R, Neves EJ. Gene expression profiles in breast tumors regarding the presence or absence of estrogen and progesterone receptors. Int J Cancer 2004; 111:892-9. [PMID: 15300801 DOI: 10.1002/ijc.20329] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Estrogen acts via its receptor (ER) to stimulate cell growth and differentiation in the mammary gland. ER and progesterone receptor (PR), which is regulated by estrogen via ER, have been used as prognostic markers in clinical management of breast cancer patients. Patients with ER- breast tumors have a poorer prognosis than patients with ER+ tumors. The aim of the present study was the identification of tumor-associated genes differentially expressed in breast tumors regarding the presence or absence of ER and PR hybridized with cDNA microarrays containing 4,500 tumor-derived expressed sequence tags generated using the ORESTES technique. Samples of human primary breast carcinomas from 38 patients were analyzed. The experiments were performed in triplicates and data from each element were acquired by phosphoimage scanning. Data acquisition was performed using the ArrayVision software. After normalization statistical analysis was applied. In a preliminary analysis, 98 differentially expressed transcripts were identified, 46 were found to be more expressed in ER+/PR+ and 52 were found to be more expressed in ER-/PR- breast tumors. The biochemical functions of the genes in the reported expression profile are diverse and include metabolic enzymes, protein kinases, helicases, transcription factors, cell cycle regulators and apoptotic factors. ER-/PR- breast tumors displayed increased levels of transcripts of genes associated with neurodegeneration and genes associated with proliferation were found in ER+/PR+ tumors.
Collapse
Affiliation(s)
- Maria Aparecida Nagai
- Disciplina de Oncologia, Departamento de Radiologia da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
| | | | | | | | | | | | | |
Collapse
|
30
|
Stains JP, Lecanda F, Screen J, Towler DA, Civitelli R. Gap junctional communication modulates gene transcription by altering the recruitment of Sp1 and Sp3 to connexin-response elements in osteoblast promoters. J Biol Chem 2003; 278:24377-87. [PMID: 12700237 DOI: 10.1074/jbc.m212554200] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Loss-of-function mutations of gap junction proteins, connexins, represent a mechanism of disease in a variety of tissues. We have shown that recessive (gene deletion) or dominant (connexin45 overexpression) disruption of connexin43 function results in osteoblast dysfunction and abnormal expression of osteoblast genes, including down-regulation of osteocalcin transcription. To elucidate the molecular mechanisms of gap junction-sensitive transcriptional regulation, we systematically analyzed the rat osteocalcin promoter for sensitivity to gap junctional intercellular communication. We identified an Sp1/Sp3 containing complex that assembles on a minimal element in the -70 to -57 region of the osteocalcin promoter in a gap junction-dependent manner. This CT-rich connexin-response element is necessary and sufficient to confer gap junction sensitivity to the osteocalcin proximal promoter. Repression of osteocalcin transcription occurs as a result of displacement of the stimulatory Sp1 by the inhibitory Sp3 on the promoter when gap junctional communication is perturbed. Modulation of Sp1/Sp3 recruitment also occurs on the collagen Ialpha1 promoter and translates into gap junction-sensitive transcriptional control of collagen Ialpha1 gene expression. Thus, regulation of Sp1/Sp3 recruitment to the promoter may represent a potential general mechanism for transcriptional control of target genes by signals passing through gap junctions.
Collapse
Affiliation(s)
- Joseph P Stains
- Division of Bone and Mineral Diseases, Washington University School of Medicine and Barnes-Jewish Hospital, St. Louis, Missouri 63110, USA
| | | | | | | | | |
Collapse
|
31
|
Sekiguchi T, Mizutani T, Yamada K, Yazawa T, Kawata H, Yoshino M, Kajitani T, Kameda T, Minegishi T, Miyamoto K. Transcriptional regulation of the epiregulin gene in the rat ovary. Endocrinology 2002; 143:4718-29. [PMID: 12446600 DOI: 10.1210/en.2002-220440] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ovarian follicular development is initiated by FSH secreted from the pituitary gland. The FSH-induced follicular development involves granulosa cell proliferation and differentiation. We demonstrated that a growth factor of epidermal growth factor (EGF) family epiregulin was rapidly induced in the primary culture of rat ovarian granulosa cells by FSH within 1 h. Epiregulin gene expression was also observed in granulosa cells of antral ovarian follicles from pregnant mare's serum gonadotropin-primed rats in vivo. To analyze the regulation of gene expression of epiregulin, we isolated and characterized the rat epiregulin gene of 22.1 kb, including 3.8 kb of 5'-upstream region as well as all five exons and four introns. We determined the transcriptional start site of rat epiregulin gene by primer extension analysis and then characterized the upstream promoter region of the gene. By using a luciferase reporter system, deletion and mutation analyses of rat epiregulin gene promoter region revealed that 125 bp upstream of transcriptional start site was essential, and that two CT boxes and one GT box within this region were important for the gene expression. We also demonstrated by EMSAs that Sp1/Sp3 proteins were involved in the epiregulin gene expression via the upstream sequence. Involvement of Sp1/Sp3 was also demonstrated that transfection of Sp1 or Sp3 expression plasmids dramatically increased the epiregulin gene promoter activities about 90- or 7.9-fold, respectively, in Drosophila SL2 cells that lack endogenous Sp family proteins. Such an increase in the promoter activity was also observed in mammalian cells when NIH-3T3 cells were used. In conclusion, we demonstrated here for the first time that EGF-type growth factor epiregulin is rapidly and strongly induced in the ovarian granulosa cells by FSH stimulation, and that two CT boxes and one GT box present in the upstream region are essential for the promoter activity of rat epiregulin. We also demonstrated that Sp family members play crucial roles in the epiregulin promoter activity through the CT boxes. The restricted and hormonally regulated expression of epiregulin in the rat ovarian granulosa cells may correspond to the physiological relevance of this peptide growth factor to the FSH-induced ovarian follicular growth and maturation.
Collapse
Affiliation(s)
- Toshio Sekiguchi
- Department of Biochemistry, Fukui Medical University, Shimoaizuki, Matsuoka, Fukui 910-1193, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
García-Ruiz I, de la Torre P, Díaz T, Esteban E, Fernández I, Muñoz-Yagüe T, Solís-Herruzo JA. Sp1 and Sp3 transcription factors mediate malondialdehyde-induced collagen alpha 1(I) gene expression in cultured hepatic stellate cells. J Biol Chem 2002; 277:30551-8. [PMID: 12055194 DOI: 10.1074/jbc.m203368200] [Citation(s) in RCA: 221] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Malondialdehyde, the end product of lipid peroxidation, has been shown to stimulate collagen alpha1(I) (Col1a1) gene expression. However, mechanisms of this effect are unclear. The purpose of this study was to clarify these mechanisms. Rat hepatic stellate cells were cultured in the presence of 200 microm malondialdehyde, and the effects on collagen gene expression and the binding of nuclear proteins to the col1a1 promoter were analyzed. Malondialdehyde treatment induced an increase in the cellular levels of col1a1 mRNA that was abrogated by pretreating cells with cycloheximide, p-hydroxymercuribenzoate, pyridoxal 5'-phosphate, and mithramycin. Transient transfections showed that malondialdehyde exerted its effect through regulatory elements located between -220 and -110 bp of the col1a1 promoter. Gel retardation assays demonstrated that malondialdehyde increased the binding of nuclear proteins to two elements located between -161 and -110 bp of the col1a1 promoter. These bindings were supershifted with Sp1 and Sp3 antibodies. Finally, malondialdehyde increased cellular levels of the Sp1 and Sp3 proteins and Sp1 mRNA. Our data indicated that treatment of hepatic stellate cells with malondialdehyde stimulated col1a1 gene expression by inducing the synthesis of Sp1 and Sp3 and their binding to two regulatory elements located between -161 and -110 bp of the col1a1 promoter.
Collapse
Affiliation(s)
- Inmaculada García-Ruiz
- Department of Gastroenterology, Research Center, Universidad Complutense Hospital Universitario 12 de Octubre, 28041-Madrid, Spain
| | | | | | | | | | | | | |
Collapse
|
33
|
Hughes TR, Tengku-Muhammad TS, Irvine SA, Ramji DP. A novel role of Sp1 and Sp3 in the interferon-gamma -mediated suppression of macrophage lipoprotein lipase gene transcription. J Biol Chem 2002; 277:11097-106. [PMID: 11796707 DOI: 10.1074/jbc.m106774200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The regulation of macrophage lipoprotein lipase by cytokines is of potentially crucial importance in the pathogenesis of atherosclerosis. We have shown previously that macrophage lipoprotein lipase expression is suppressed by interferon-gamma (IFN-gamma) at the transcriptional level. We investigated the regulatory sequence elements and the transcription factors that are involved in this response. We demonstrated that the -31/+187 sequence contains the minimal IFN-gamma-responsive elements. Electrophoretic mobility shift assays showed that the binding of proteins to two regions in the -31/+187 sequence was reduced dramatically when the cells were exposed to IFN-gamma. Both competition electrophoretic mobility shift assays and antibody supershift assays showed that the interacting proteins were composed of Sp1 and Sp3. Mutations of the Sp1/Sp3-binding sites in the minimal IFN-gamma-responsive elements abolished the IFN-gamma-mediated suppression of promoter activity, whereas multimers of the sequence were able to impart the response to a heterologous promoter. Western blot analysis showed that IFN-gamma reduced the steady state levels of Sp3 protein. In contrast, the cytokine decreased the DNA binding activity of Sp1 without affecting the protein levels. These studies therefore reveal a novel mechanism for IFN-gamma-mediated regulation of macrophage gene transcription.
Collapse
Affiliation(s)
- Timothy R Hughes
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, P. O. Box 911, Cardiff CF10 3US, United Kingdom
| | | | | | | |
Collapse
|
34
|
Hu HM, Arcinas M, Boxer LM. A Myc-associated zinc finger protein-related factor binding site is required for the deregulation of c-myc expression by the immunoglobulin heavy chain gene enhancers in Burkitt's lymphoma. J Biol Chem 2002; 277:9819-24. [PMID: 11777933 DOI: 10.1074/jbc.m111426200] [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: 11/06/2022] Open
Abstract
The deregulation of expression of the c-myc gene in Burkitt's lymphoma results from the translocation that links one c-myc allele to one of the immunoglobulin genes. This physical linkage promotes interactions between c-myc and immunoglobulin gene regulatory elements that affect c-myc transcription initiation and elongation. We have located a region in the c-myc promoter that is required for the complete activation by the immunoglobulin heavy chain gene enhancer. This regulatory element contains a core sequence, GGGAGG, similar to the GA box recognized by the transcription factor Myc-associated zinc finger protein (MAZ). UV cross-link analysis indicated that the mass of this protein did not correspond to that of MAZ, suggesting that a protein related to but distinct from MAZ bound to this site. Mutation of this regulatory element resulted in a loss of promoter activity induced by the immunoglobulin heavy chain gene enhancer. This site was also required for the c-myc promoter shift from P2 to P1. In vivo footprinting revealed that this site was occupied on the translocated c-myc allele but not on the untranslocated allele. Taken together, these findings suggest that this regulatory element is required for the full activation of c-myc promoter activity by the immunoglobulin heavy chain gene enhancer.
Collapse
Affiliation(s)
- Hsien-Ming Hu
- Center for Molecular Biology in Medicine, Veterans Affairs Palo Alto Health Care System, Stanford University School of Medicine, Stanford, California 94305, USA
| | | | | |
Collapse
|
35
|
Ugai H, Li HO, Komatsu M, Tsutsui H, Song J, Shiga T, Fearon E, Murata T, Yokoyama KK. Interaction of Myc-associated zinc finger protein with DCC, the product of a tumor-suppressor gene, during the neural differentiation of P19 EC cells. Biochem Biophys Res Commun 2001; 286:1087-97. [PMID: 11527412 DOI: 10.1006/bbrc.2001.5469] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Expression of the DCC (deleted in colorectal cancer) protein is strongly induced during the neural differentiation of mouse P19 embryonal carcinoma (EC) cells that occurs when these cells are treated with retinoic acid (RA). Myc-associated zinc finger protein (MAZ) is a DNA-binding protein that is widely expressed and functions in human, mouse and hamster cells as an activator, an initiator or a terminator of transcription. However, the biological functions of MAZ remain elusive. We report here that MAZ associates with the cytoplasmic domain of the DCC protein in vivo and in vitro. Yeast two-hybrid assays confirmed this association. An immunofluorescence study demonstrated that DCC protein is expressed at elevated levels in neuron-like P19 EC cells, in particular in axons, in which the MAZ protein is also expressed. We found that MAZ was translocated from the nucleus to the cytoplasm during the RA-induced terminal differentiation of P19 EC cells with resultant loss of the ability of MAZ to bind to the ME1a1 site of the c-myc promoter. Taken together, our observations imply that the DCC protein might play a critical role as a signaling molecule in the regulation of the transcriptional activity of MAZ during the neural differentiation of P19 EC cells.
Collapse
MESH Headings
- Active Transport, Cell Nucleus
- Amino Acid Sequence
- Animals
- Binding Sites
- Blotting, Northern
- Blotting, Western
- Cell Adhesion Molecules/metabolism
- Cell Differentiation
- Cell Line
- Cell Nucleus/metabolism
- Cytoplasm/metabolism
- DCC Receptor
- DNA-Binding Proteins
- Genes, myc/genetics
- Humans
- Immunohistochemistry
- Microscopy, Fluorescence
- Models, Biological
- Molecular Sequence Data
- Neurons/metabolism
- Plasmids/metabolism
- Precipitin Tests
- Promoter Regions, Genetic
- Protein Binding
- Protein Structure, Tertiary
- RNA/metabolism
- RNA, Messenger/metabolism
- Receptors, Cell Surface
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Signal Transduction
- Time Factors
- Transcription Factors/metabolism
- Transcription, Genetic
- Transfection
- Tretinoin/metabolism
- Tumor Suppressor Proteins
- Two-Hybrid System Techniques
- Xenopus
- Zinc Fingers
Collapse
Affiliation(s)
- H Ugai
- Gene Engineering Division, Bioresource Center, Tsukuba Institute, RIKEN (The Institute of Physical and Chemical Research), 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Matsumoto K, Taniura H, Uetsuki T, Yoshikawa K. Necdin acts as a transcriptional repressor that interacts with multiple guanosine clusters. Gene 2001; 272:173-9. [PMID: 11470523 DOI: 10.1016/s0378-1119(01)00544-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Necdin is a growth suppressor expressed predominantly in postmitotic neurons, and ectopic expression of this protein suppresses cell growth. Here we report that Necdin directly binds to specific DNA sequences and serves as a transcriptional repressor. Polyhistidine-tagged Necdin was used for selection of random-sequence oligonucleotides by polymerase chain reaction-based amplification. Necdin recognized guanosine (G)-rich sequences that encompass multiple G clusters and intervening mono- or di-nucleotides of A, T and C. These sequences, termed GN boxes, resemble multiply aligned forms of the canonical GC box which is recognized by Sp family members. Necdin directly bound to a GN box consisting of contiguous two GC boxes with four G clusters, but not to a single GC box with two G clusters, whereas Sp1 bound to both. In a reporter system using Drosophila Schneider Line 2 cells, Necdin repressed Sp1-dependent activity of mouse c-myc P1 promoter that contains a typical GN box. Deletion of the GN box from the c-myc P1 promoter or its conversion to the single GC box abolished the Necdin-dependent repression. These results suggest that Necdin modulates gene transcription via the GN box that is potentially recognized by GC box-targeting Sp family members.
Collapse
Affiliation(s)
- K Matsumoto
- Division of Regulation of Macromolecular Functions, Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | | | | | | |
Collapse
|
37
|
Albert T, Wells J, Funk JO, Pullner A, Raschke EE, Stelzer G, Meisterernst M, Farnham PJ, Eick D. The chromatin structure of the dual c-myc promoter P1/P2 is regulated by separate elements. J Biol Chem 2001; 276:20482-90. [PMID: 11279041 DOI: 10.1074/jbc.m100265200] [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 proto-oncogene c-myc is transcribed from a dual promoter P1/P2, with transcription initiation sites 160 base pairs apart. Here we have studied the transcriptional activation of both promoters on chromatin templates. c-myc chromatin was reconstituted on stably transfected, episomal, Epstein-Barr virus-derived vectors in a B cell line. Episomal P1 and P2 promoters showed only basal activity but were strongly inducible by histone deacetylase inhibitors. The effect of promoter mutations on c-myc activity, chromatin structure, and E2F binding was studied. The ME1a1 binding site between P1 and P2 was required for the maintenance of an open chromatin configuration of the dual c-myc promoters. Mutation of this site strongly reduced the sensitivity of the core promoter region of P1/P2 to micrococcal nuclease and prevented binding of polymerase II (pol II) at the P2 promoter. In contrast, mutation of the P2 TATA box also abolished binding of pol II at the P2 promoter but did not affect the chromatin structure of the P1/P2 core promoter region. The E2F binding site adjacent to ME1a1 is required for repression of the P2 promoter but not the P1 promoter, likely by recruitment of histone deacetylase activity. Chromatin precipitation experiments with E2F-specific antibodies revealed binding of E2F-1, E2F-2, and E2F-4 to the E2F site of the c-myc promoter in vivo if the E2F site was intact. Taken together, the analyses support a model with a functional hierarchy for regulatory elements in the c-myc promoter region; binding of proteins to the ME1a1 site provides a nucleosome-free region of chromatin near the P2 start site, binding of E2F results in transcriptional repression without affecting polymerase recruitment, and the TATA box is required for polymerase recruitment.
Collapse
Affiliation(s)
- T Albert
- Institute of Clinical Molecular Biology and Tumor Genetics, Department for Protein Chemistry, Research Centre for Environment and Health (GSF), Marchioninistrasse 25, D-81377 München, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Song J, Ugai H, Kanazawa I, Sun K, Yokoyama KK. Independent repression of a GC-rich housekeeping gene by Sp1 and MAZ involves the same cis-elements. J Biol Chem 2001; 276:19897-904. [PMID: 11259406 DOI: 10.1074/jbc.m010658200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transcription factors Sp1 and MAZ (Myc-associated zinc finger protein) contain several zinc finger motifs, and each functions as both a positive and a negative regulator of gene expression. In this study, we characterized the extremely GC-rich promoter of the human gene for MAZ, which is known as a housekeeping gene. Unique symmetrical motifs in the promoter region (nucleotides -383 to -334) were essential for the expression of the gene for MAZ, whereas an upstream silencer element (nucleotides -784 to -612) was found to act in a position-dependent but orientation-independent manner. Sp1 and MAZ bound to the same cis-elements in the GC-rich promoter, apparently sharing DNA-binding sites. The relative extent of binding of Sp1 and MAZ to these cis-elements corresponded to the extent of negative regulation of the expression of the gene for MAZ in various lines of cells. Furthermore, novel repressive domains in both Sp1 (amino acids 622-788) and MAZ (amino acids 127-292) were identified. Suppression by Sp1 and suppression by MAZ were independent phenomena; histone deacetylases were involved in the autorepression by MAZ itself, whereas DNA methyltransferase 1 was associated with suppression by Sp1. Our results indicate that both deacetylation and methylation might be involved in the regulation of expression of a single gene via the actions of different zinc finger proteins that bind to the same cis-elements.
Collapse
Affiliation(s)
- J Song
- RIKEN (The Insitute of Physical & Chemical Research), Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | | | | | | | | |
Collapse
|
39
|
Bourgarel-Rey V, Vallee S, Rimet O, Champion S, Braguer D, Desobry A, Briand C, Barra Y. Involvement of nuclear factor kappaB in c-Myc induction by tubulin polymerization inhibitors. Mol Pharmacol 2001; 59:1165-70. [PMID: 11306700 DOI: 10.1124/mol.59.5.1165] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We showed previously that microtubule disassembly by vinblastine induces the proto-oncogene c-myc in epithelial mammary HBL100 cells. In this study, we demonstrate that vinblastine treatment in these cells, in contrast to what was observed with the colon adenocarcinoma cell line HT29-D4, activated the transcription factor NFkappaB, which has been involved in c-myc regulation. The microtubule disassembly also induced IkappaB degradation. Using transient transfection analysis, we show that the trans-activation of c-myc by vinblastine was decreased when NFkappaB binding sites on c-myc promoter were mutated. Additionally, we demonstrate that microtubule dissolution trans-activated a thymidine kinase-CAT construct containing an NFkappaB binding site at -1180 to -1080 bp relative to the P1 promoter. Thus, vinblastine up-regulates the enhancer activity of the NFkappaB binding site. These results suggest that microtubule disassembly induced by vinblastine can trans-activate the c-myc oncogene through NFkappaB. Taking into consideration the paradoxical roles of both c-myc and NFkappaB in proliferation or apoptosis, this data reveals the complex action mechanism of this microtubule interfering agent.
Collapse
Affiliation(s)
- V Bourgarel-Rey
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 6032, Faculté de Pharmacie, Marseille, France
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Ko JL, Loh HH. Single-stranded DNA-binding complex involved in transcriptional regulation of mouse mu-opioid receptor gene. J Biol Chem 2001; 276:788-95. [PMID: 11027679 DOI: 10.1074/jbc.m004279200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previously, we reported the presence of dual (distal and proximal) promoters in mouse mu-opioid receptor (mor) gene, with mor transcription in mouse brain predominantly initiated by the proximal promoter. Sp factors, bound to double-stranded (ds) cis-regulatory elements, are critical for proximal promoter activity. Here, we further report that a single-stranded (ss) cis-regulatory element and trans-acting protein factor are also important for proximal promoter activity. A 26-bp mor polypyrimidine/polypurine region (PPy/u) can adopt ss DNA conformation, as demonstrated by S1 nuclease sensitivity. Using electrophoretic mobility shift analysis with nuclear extracts from mor-expressing SH-SY5Y cells, we demonstrate that the sense strand of PPy/u interacts with a major nuclear protein, termed mor polypyrimidine-binding protein (mPy), which is not related to Sp factors. Southwestern blot analysis indicated that mPy protein is approximately 25 kDa in size. Functional analysis suggests that mPy protein can trans-activate mor promoter as well as a heterologous promoter. Moreover, combinatorial activation of ss (mPy) and ds (Sps) DNA binding factors, interacting with an overlapping DNA (PPy/u) region, is necessary for proximal promoter activation. Thus our results suggest that transcription of mouse mor gene is regulated by an interplay of ss and ds DNA binding factors.
Collapse
Affiliation(s)
- J L Ko
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA.
| | | |
Collapse
|
41
|
Simonsson T, Pribylova M, Vorlickova M. A nuclease hypersensitive element in the human c-myc promoter adopts several distinct i-tetraplex structures. Biochem Biophys Res Commun 2000; 278:158-66. [PMID: 11071868 DOI: 10.1006/bbrc.2000.3783] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nucleic acid structure-function correlations are pivotal to major biological events like transcription, replication, and recombination. Depending on intracellular conditions in vivo and buffer composition in vitro, DNA appears capable of inexhaustible structure variation. At moderately acidic, or even neutral pH, DNA strands that are rich in cytosine bases can associate both inter- and intramolecularly to form i-tetraplexes. The hemiprotonated cytosine(+)-cytosine base pair constitutes the building block for the formation of i-tetraplexes, and motifs for their formation are frequent in vertebrate genomes. A major control element upstream of the human c-myc gene, which has been shown to interact sequence specifically with several transcription factors, becomes hypersensitive to nucleases upon c-myc expression. The control element is asymmetric inasmuch as that one strand is uncommonly rich in cytosines and exhibits multiple motifs for the formation of i-tetraplexes. To investigate the propensity for their formation we employ circular dichroism (CD) in combination with ultra violet (UV) spectroscopy and native gel electrophoresis. Our results demonstrate the cooperative formation of well-defined i-tetraplex structures. We conclude that i-tetraplex formation occurs in the promoter region of the human c-myc gene in vitro, and discuss implications of possible biological roles for i-tetraplex structures in vivo. Hypothetical formation of intramolecular fold-back i-tetraplexes is important to c-myc transcription, whereas chromosomal translocation events might involve the formation of bimolecular i-tetraplex structures.
Collapse
Affiliation(s)
- T Simonsson
- Department of Molecular Biotechnology, Chalmers University of Technology, SE 405 30 Göteborg, Sweden.
| | | | | |
Collapse
|
42
|
Gartel AL, Goufman E, Najmabadi F, Tyner AL. Sp1 and Sp3 activate p21 (WAF1/CIP1) gene transcription in the Caco-2 colon adenocarcinoma cell line. Oncogene 2000; 19:5182-8. [PMID: 11064455 DOI: 10.1038/sj.onc.1203900] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The CDK inhibitor p21WAF1/CIP1 is a negative regulator of the cell cycle, and its expression is induced during terminal differentiation in vitro and in vivo. Expression of p21 is controlled at the transcriptional level by both p53-dependent and -independent mechanisms. Our previous studies established that p21 is expressed in the Caco-2 adenocarcinoma cell line, and its expression is induced by a p53-independent mechanism during differentiation of these cells. Here we have found that transcription of p21 in Caco-2 cells is controlled primarily by the transcription factors Sp1 and Sp3 through two Sp1 binding sites, Sp1-1 and Sp1-2, located between -119 and -114 bp and between -109 and -104 bp of the p21 promoter, respectively. Sp1 and Sp3 binding to the p21 promoter increased during Caco-2 cell differentiation, while the absolute level of Sp1 did not change and the absolute level of Sp3 increased approximately twofold. Transfection experiments in the SL2 Drosophila cell line that lacks endogenous Sp3 activity demonstrated that Sp1 transactivates the p21 promoter primarily through the Sp1-2 site, while Sp3 acts through the Sp1-1 site. In these cells Sp3 is a stronger transactivator of the p21 promoter than Sp1. Our data suggest that induction of p21 transcription during Caco-2 differentiation is modulated by Sp1/Sp3 interactions with the p21 promoter.
Collapse
Affiliation(s)
- A L Gartel
- Department of Molecular Genetics, University of Illinois at Chicago, 900 S. Ashland Avenue, Chicago, Illinois, IL 60607, USA
| | | | | | | |
Collapse
|
43
|
Tsutsui H, Geltinger C, Murata T, Itakura K, Wada T, Handa H, Yokoyama KK. The DNA-binding and transcriptional activities of MAZ, a myc-associated zinc finger protein, are regulated by casein kinase II. Biochem Biophys Res Commun 1999; 262:198-205. [PMID: 10448092 DOI: 10.1006/bbrc.1999.1130] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myc-associated zinc finger protein (MAZ) is a transcription factor that contains proline-rich, alanine repeats and six C(2)H(2)-type zinc finger motifs, as well as five putative sites of phosphorylation by casein kinase II (CKII). Site-specific mutagenesis of MAZ revealed that the serine residue at position 480 was the major site of phosphorylation by CKII both in vitro and in vivo. Phosphorylation of MAZ by CKII at this serine residue was required for maximum binding of MAZ to the pyrimidine-rich DNA of the nuclease-hypersensitive element (NHE) in the 5'-end promoter region of the c-myc gene. Mutation of serine at position 480 to alanine eliminated the DNA-binding activity of MAZ to this element. Moreover, the mutated MAZ was unable to enhance the expression of luciferase encoded by a c-myc promoter/luciferase reporter gene in HeLa cells in the presence of CKII. These results suggest that phosphorylation of the serine residue at position 480 of MAZ by CKII can control the function of MAZ by altering its DNA-binding activity.
Collapse
Affiliation(s)
- H Tsutsui
- Tsukuba Life Science Center, RIKEN (The Institute of Physical and Chemical Research), 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan
| | | | | | | | | | | | | |
Collapse
|
44
|
Her S, Bell RA, Bloom AK, Siddall BJ, Wong DL. Phenylethanolamine N-methyltransferase gene expression. Sp1 and MAZ potential for tissue-specific expression. J Biol Chem 1999; 274:8698-707. [PMID: 10085109 DOI: 10.1074/jbc.274.13.8698] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Phenylethanolamine N-methyltransferase (PNMT) promoter-luciferase reporter gene constructs (pGL3RP863, pGL3RP444, and pGL3RP392) transfected into COS1, RS1, PC12, NIH/3T3, or Neuro2A cells showed the highest basal luciferase activity in the Neuro2A cells. DNase I footprinting with Neuro2A cell nuclear extract identified protected PNMT promoter regions spanning the -168/-165 and -48/-45 base pair Sp1/Egr-1 binding sites. Gel mobility shift assays and transient transfection assays using site-directed mutant PNMT promoter-luciferase reporter gene constructs indicated that the elevated basal luciferase activity in the Neuro2A cells was mediated by Sp-1. Furthermore, activation of the PNMT promoter by Sp1 depends on both its binding affinity for its cognate target sequences and its intracellular concentrations. When Sp1 levels were increased through an expression plasmid, luciferase reporter gene expression rose well beyond basal wild-type levels, even with either Sp1 binding element mutated. Finally, another transcription factor expressed in the Neuro2A cells competes with Sp1 by interacting with DNA sequences 3' to the -48 base pair Sp1 site to prevent Sp1 binding and induction of the PNMT promoter. The DNA consensus sequence, Southwestern analysis, and gel mobility shift assays with antibodies identify MAZ as the competitive factor. These findings suggest that Sp1 may potentially contribute to the tissue-specific expression of the PNMT gene, with the competition between Sp1 and MAZ conferring additional tissue-specific control.
Collapse
Affiliation(s)
- S Her
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California 94305-5485, USA
| | | | | | | | | |
Collapse
|
45
|
Xu G, Goodridge AG. Function of a C-rich sequence in the polypyrimidine/polypurine tract of the promoter of the chicken malic enzyme gene depends on promoter context. Arch Biochem Biophys 1999; 363:202-12. [PMID: 10068441 DOI: 10.1006/abbi.1998.1083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The promoters of many genes contain C-rich polypyrimidine/polypurine (PPY/PPU) sequences that are important for gene expression. The promoter of the chicken malic enzyme gene contains a long PPY/PPU tract that can act as an alternative promoter. This tract can be separated functionally into a C-rich and (CT)7 sequences. The (CT)7 region together with some 3' nucleotides is essential for function of the alternative transcription start site and the C-rich sequence as a regulatory element. In constructs that contained the PPY/PPU tract or the -147/+31-bp promoter of the malic enzyme gene connected to a reporter gene, deletion of the C-rich region increased gene expression. In constructs containing 5.8-kb 5'-flanking DNA of the gene, deletion of the same C-rich region decreased expression of the reporter gene. Positive function of the C-rich sequence required two upstream DNA regions, -237 to -147 bp and -3474 to -2715 bp. To understand the mechanism(s) by which the same sequence exerts different effects, we examined the transcription start sites in the construct where the C-rich region was deleted. We directly visualized transcription start sites by performing 5'-rapid amplification of cDNA ends and a subsequent primer extension on a single-stranded template. Deletion of the C-rich region from constructs containing 5.8 kb of 5'-flanking DNA almost completely abolished transcription initiation from the PPY/PPU promoter and reduced transcription from the major endogenous start site. DEAE fractionation of hepatic nuclear extract revealed more than 10 proteins that bound specifically to C-rich DNA. These results suggest that interactions between upstream DNA elements and the C-rich sequence and the selective use of DNA-binding activities may bestow different functions on the same nucleotide sequence.
Collapse
Affiliation(s)
- G Xu
- Department of Biochemistry, University of Iowa, Iowa City, Iowa, 52240, USA
| | | |
Collapse
|
46
|
Gerbitz A, Mautner J, Geltinger C, Hörtnagel K, Christoph B, Asenbauer H, Klobeck G, Polack A, Bornkamm GW. Deregulation of the proto-oncogene c-myc through t(8;22) translocation in Burkitt's lymphoma. Oncogene 1999; 18:1745-53. [PMID: 10208435 DOI: 10.1038/sj.onc.1202468] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In Burkitt's lymphoma (BL) cells the proto-oncogene c-myc is juxtaposed to one of the immunoglobulin (Ig) loci on chromosomes 2, 14, or 22. The c-myc gene becomes transcriptionally activated as a consequence of the chromosomal translocation and shows preferential usage of promoter P1 over P2, a phenomenon referred to as promoter shift. In order to define the responsible regulatory elements within the Ig lambda locus, we studied the effect of the human Ig lambda enhancer (HuE lambda) on c-myc expression after stable transfection into BL cells. A 12 kb genomic fragment encompassing HuE lambda, but not HuE lambda alone, strongly activated c-myc expression and induced the promoter shift. To identify additional elements involved in c-myc deregulation, we mapped DNaseI hypersensitive sites within the 12 kb lambda fragment on the construct. Besides one hypersensitive site corresponding to HuE lambda, three additional sites were detected. Two of these elements displayed enhancer activity after transient transfection. The third element did not activate c-myc transcription, but was required for full c-myc activation and promoter shift. Deletion analyses of the c-myc promoter identified the immediate promoter region as sufficient for activation by the Ig lambda. locus, but also revealed that induction of the promoter shift requires additional upstream elements.
Collapse
Affiliation(s)
- A Gerbitz
- Dana Farber Cancer Institute, Pediatric Oncology, Boston, Massachusetts 02115, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Song J, Murakami H, Tsutsui H, Ugai H, Geltinger C, Murata T, Matsumura M, Itakura K, Kanazawa I, Sun K, Yokoyama KK. Structural organization and expression of the mouse gene for Pur-1, a highly conserved homolog of the human MAZ gene. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 259:676-83. [PMID: 10092852 DOI: 10.1046/j.1432-1327.1999.00081.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have characterized the genomic structure and expression of the mouse gene for Pur-1. The cloned Pur-1 gene spans a 5-kb region encompassing the promoter, five exons, four introns and the 3'-untranslated region. All exon-intron junction sequences conform to the GT/AG rule. The promoter region has typical features of a housekeeping gene: a high G + C content (77.5%); a high frequency of CpG dinucleotides, in particular within the region 0.5 kb upstream of the site of initiation of translation; and the absence of canonical TATA and CAAT boxes. S1 nuclease protection assay demonstrated the presence of multiple sites for initiation of transcription around a site 108 nucleotides upstream of the ATG codon. Comparison of Pur-1 with the human gene for MAZ (Myc-associated zinc finger protein) revealed a striking homology of both their nucleotide and deduced protein sequences, an identical genomic organization and high similarity in promoter architecture and mRNA expression pattern. Sequence analysis of the 5'-flanking region of Pur-1 revealed numerous potential binding sites for transcription factors Sp1, AP-2 and Pur-1/MAZ itself. An element required for basal Pur-1 expression was mapped from nucleotide -258 to +43. This region also mediated stimulation of basal transcription by ectopically expressed MAZ protein. We conclude that the Pur-1 gene is the murine homolog of human MAZ and, like it, belongs to the family of housekeeping genes.
Collapse
Affiliation(s)
- J Song
- Tsukuba Life Science Center, Ibaraki, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Karantzoulis-Fegaras F, Antoniou H, Lai SL, Kulkarni G, D'Abreo C, Wong GK, Miller TL, Chan Y, Atkins J, Wang Y, Marsden PA. Characterization of the human endothelial nitric-oxide synthase promoter. J Biol Chem 1999; 274:3076-93. [PMID: 9915847 DOI: 10.1074/jbc.274.5.3076] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Understanding transcription initiation of the endothelial nitric-oxide synthase (eNOS) gene appears pivotal to gaining a comprehensive view of NO biology in the blood vessel wall. The present study therefore focused upon a detailed dissection of the functionally important cis-DNA elements and the multiprotein complexes implicated in the cooperative control of constitutive expression of the human eNOS gene in vascular endothelium. Two tightly clustered cis-regulatory regions were identified in the proximal enhancer of the TATA-less eNOS promoter using deletion analysis and linker-scanning mutagenesis: positive regulatory domains I (-104/-95 relative to transcription initiation) and II (-144/-115). Analysis of trans-factor binding and functional expression studies revealed a surprising degree of cooperativity and complexity. The nucleoprotein complexes that form upon these regions in endothelial cells contained Ets family members, Sp1, variants of Sp3, MAZ, and YY1. Functional domain studies in Drosophila Schneider cells and endothelial cells revealed examples of positive and negative protein-protein cooperativity involving Sp1, variants of Sp3, Ets-1, Elf-1, and MAZ. Therefore, multiprotein complexes are formed on the activator recognition sites within this 50-base pair region of the human eNOS promoter in vascular endothelium.
Collapse
Affiliation(s)
- F Karantzoulis-Fegaras
- Renal Division and Department of Medicine, St. Michael's Hospital and University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Ungefroren H, Gellersen B, Krull NB, Kalthoff H. Biglycan gene expression in the human leiomyosarcoma cell line SK-UT-1. Basal and protein kinase A-induced transcription involves binding of Sp1-like/Sp3 proteins in the proximal promoter region. J Biol Chem 1998; 273:29230-40. [PMID: 9786935 DOI: 10.1074/jbc.273.44.29230] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In this study we demonstrate that the gene encoding the small leucine-rich proteoglycan biglycan is expressed in human myometrial tissue and in the human leiomyosarcoma cell line SK-UT-1. Treatment of SK-UT-1 cells with forskolin or 8-bromo-cAMP strongly increased biglycan mRNA and this effect was transcriptional as shown by transient transfection experiments with biglycan promoter-luciferase reporter fusion genes. The cAMP-mediated induction of the transfected biglycan promoter in SK-UT-1 cells was abolished by coexpression of a specific protein kinase A inhibitor, and was mimicked by overexpression of the catalytic subunit (Cbeta) of protein kinase A. By 5' deletion analysis, part of the cAMP response was localized to the segment from residues -78 to -46 of the biglycan promoter. This region conferred strong cAMP responsiveness to a heterologous promoter. Electrophoretic mobility shift and antibody supershift assays identified two specific complexes that contained nuclear proteins antigenically related to the ubiquitous transcription factors Sp1 and Sp3, respectively. The binding site of these proteins was mapped to a CT-rich sequence extending from -59 to -49 in the biglycan promoter. Mutating this sequence eliminated complex formation and markedly reduced basal and cAMP-dependent promoter activity of transfected reporter genes. In vitro binding studies using recombinant Sp1 revealed that the nuclear factor binding to the CT element was not Sp1 but a Sp1-like protein(s). Western blot analysis of SK-UT-1 nuclear proteins confirmed expression of Sp3, Sp1 and nuclear proteins that crossreacted with Sp1 antibody but according to their molecular weight were not Sp1. These results indicate that all cAMP-dependent as well as some basal biglycan transcription in SK-UT-1 cells is mediated through activated protein kinase A and that both functions are conferred at the promoter level through the interaction of Sp1-like/Sp3 factors with the CT element at -59 in the biglycan promoter.
Collapse
Affiliation(s)
- H Ungefroren
- Research Unit Molecular Oncology, Clinic for General Surgery and Thoracic Surgery, Christian-Albrechts University, 24105 Kiel, Germany.
| | | | | | | |
Collapse
|
50
|
Ko JL, Liu HC, Minnerath SR, Loh HH. Transcriptional regulation of mouse mu-opioid receptor gene. J Biol Chem 1998; 273:27678-85. [PMID: 9765304 DOI: 10.1074/jbc.273.42.27678] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previously, the existence of dual promoters was reported in mouse mu-opioid receptor (mor) gene, with mor transcription in the mouse brain predominantly initiated by the proximal promoter. In this study, we further analyzed the proximal promoter region, base pairs -450 to -249, to identify cis-DNA regulatory elements and trans-acting protein factors that are important for mor promoter activity. The results revealed that a mor inverted GA (iGA) motif and a canonical Sp1 binding site are required for the promoter activity. Using electrophoretic mobility shift analysis, we identified nuclear proteins that specifically bind to the mor iGA motif and that are immunologically related to Sp1 and Sp3. Mutation of the mor iGA motif, resulting in a loss of Sp binding, led to a 50% decrease in activity. Mutation of the canonical Sp1 binding site yielded a lesser (approximately 25%) loss of activity. Mutation of both motifs together resulted in an approximately 70% decrease in activity. In cotransfection assays using Drosophila SL2 cells, Sp1 trans-activated the promoter in a manner dependent on the presence of mor iGA and canonical Sp1 binding motifs. Sp3 can also trans-activate the promoter, and furthermore, Sp1 and Sp3 can trans-activate the mor promoter additively. Our results suggest that combined or cooperative interaction of Sp transcription factors within the proximal promoter is necessary for activation of mor gene transcription.
Collapse
Affiliation(s)
- J L Ko
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | | | | | | |
Collapse
|