1
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Epasto LM, Pötzl C, Peterlik H, Khalil M, Saint‐Pierre C, Gasparutto D, Sicoli G, Kurzbach D. NMR-identification of the interaction between BRCA1 and the intrinsically disordered monomer of the Myc-associated factor X. Protein Sci 2024; 33:e4849. [PMID: 38037490 PMCID: PMC10731500 DOI: 10.1002/pro.4849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/17/2023] [Accepted: 11/27/2023] [Indexed: 12/02/2023]
Abstract
The breast cancer susceptibility 1 (BRCA1) protein plays a pivotal role in modulating the transcriptional activity of the vital intrinsically disordered transcription factor MYC. In this regard, mutations of BRCA1 and interruption of its regulatory activity are related to hereditary breast and ovarian cancer (HBOC). Interestingly, so far, MYC's main dimerization partner MAX (MYC-associated factor X) has not been found to bind BRCA1 despite a high sequence similarity between both oncoproteins. Herein, we show that a potential reason for this discrepancy is the heterogeneous conformational space of MAX, which encloses a well-documented folded coiled-coil homodimer as well as a less common intrinsically disordered monomer state-contrary to MYC, which exists mostly as intrinsically disordered protein in the absence of any binding partner. We show that when the intrinsically disordered state of MAX is artificially overpopulated, the binding of MAX to BRCA1 can readily be observed. We characterize this interaction by nuclear magnetic resonance (NMR) spectroscopy chemical shift and relaxation measurements, complemented with ITC and SAXS data. Our results suggest that BRCA1 directly binds the MAX monomer to form a disordered complex. Though probed herein under biomimetic in-vitro conditions, this finding can potentially stimulate new perspectives on the regulatory network around BRCA1 and its involvement in MYC:MAX regulation.
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Affiliation(s)
- Ludovica Martina Epasto
- Faculty of Chemistry, Institute for Biological ChemistryUniversity of ViennaViennaAustria
- Vienna Doctoral School in Chemistry (DoSChem)University of ViennaViennaAustria
| | - Christopher Pötzl
- Faculty of Chemistry, Institute for Biological ChemistryUniversity of ViennaViennaAustria
- Vienna Doctoral School in Chemistry (DoSChem)University of ViennaViennaAustria
| | | | - Mahdi Khalil
- CNRS UMR 8516, LASIREUniversity of LilleVilleneuve d'Ascq CedexFrance
| | | | | | - Giuseppe Sicoli
- CNRS UMR 8516, LASIREUniversity of LilleVilleneuve d'Ascq CedexFrance
| | - Dennis Kurzbach
- Faculty of Chemistry, Institute for Biological ChemistryUniversity of ViennaViennaAustria
- Vienna Doctoral School in Chemistry (DoSChem)University of ViennaViennaAustria
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2
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Schütz S, Bergsdorf C, Goretzki B, Lingel A, Renatus M, Gossert AD, Jahnke W. The disordered MAX N-terminus modulates DNA binding of the transcription factor MYC:MAX. J Mol Biol 2022; 434:167833. [PMID: 36174765 DOI: 10.1016/j.jmb.2022.167833] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/05/2022] [Accepted: 09/17/2022] [Indexed: 11/15/2022]
Abstract
The intrinsically disordered protein MYC belongs to the family of basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factors (TFs). In complex with its cognate binding partner MAX, MYC preferentially binds to E-Box promotor sequences where it controls fundamental cellular processes such as cell cycle progression, metabolism, and apoptosis. Intramolecular regulation of MYC:MAX has not yet been investigated in detail. In this work, we use Nuclear Magnetic Resonance (NMR) spectroscopy to identify and map interactions between the disordered MAX N-terminus and the MYC:MAX DNA binding domain (DBD). We find that this binding event is mainly driven by electrostatic interactions and that it is competitive with DNA binding. Using Nuclear Magnetic resonance (NMR) spectroscopy and Surface Plasmon Resonance (SPR), we demonstrate that the MAX N-terminus serves to accelerate DNA binding kinetics of MYC:MAX and MAX:MAX dimers, while it simultaneously provides specificity for E-Box DNA. We also establish that these effects are further enhanced by Casein Kinase 2-mediated phosphorylation of two serine residues in the MAX N-terminus. Our work provides new insights how bHLH-LZ TFs are regulated by intramolecular interactions between disordered regions and the folded DNA binding domain.
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Affiliation(s)
- Stefan Schütz
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Christian Bergsdorf
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Benedikt Goretzki
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Andreas Lingel
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Martin Renatus
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Alvar D Gossert
- Department of Biology, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Wolfgang Jahnke
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland.
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3
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Epasto LM, Che K, Kozak F, Selimovic A, Kadeřávek P, Kurzbach D. Toward protein NMR at physiological concentrations by hyperpolarized water-Finding and mapping uncharted conformational spaces. SCIENCE ADVANCES 2022; 8:eabq5179. [PMID: 35930648 PMCID: PMC9355353 DOI: 10.1126/sciadv.abq5179] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a key method for determining the structural dynamics of proteins in their native solution state. However, the low sensitivity of NMR typically necessitates nonphysiologically high sample concentrations, which often limit the relevance of the recorded data. We show how to use hyperpolarized water by dissolution dynamic nuclear polarization (DDNP) to acquire protein spectra at concentrations of 1 μM within seconds and with a high signal-to-noise ratio. The importance of approaching physiological concentrations is demonstrated for the vital MYC-associated factor X, which we show to switch conformations when diluted. While in vitro conditions lead to a population of the well-documented dimer, concentrations lowered by more than two orders of magnitude entail dimer dissociation and formation of a globularly folded monomer. We identified this structure by integrating DDNP with computational techniques to overcome the often-encountered constraint of DDNP of limited structural information provided by the typically detected one-dimensional spectra.
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Affiliation(s)
- Ludovica M. Epasto
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
| | - Kateryna Che
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
| | - Fanny Kozak
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
| | - Albina Selimovic
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
| | - Pavel Kadeřávek
- Masaryk University, CEITEC, Kamenice 5, 625 00 Brno, Czech Republic
| | - Dennis Kurzbach
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090 Vienna, Austria
- Corresponding author.
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4
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Hilty C, Kurzbach D, Frydman L. Hyperpolarized water as universal sensitivity booster in biomolecular NMR. Nat Protoc 2022; 17:1621-1657. [PMID: 35546640 DOI: 10.1038/s41596-022-00693-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 02/25/2022] [Indexed: 11/09/2022]
Abstract
NMR spectroscopy is the only method to access the structural dynamics of biomolecules at high (atomistic) resolution in their native solution state. However, this method's low sensitivity has two important consequences: (i) typically experiments have to be performed at high concentrations that increase sensitivity but are not physiological, and (ii) signals have to be accumulated over long periods, complicating the determination of interaction kinetics on the order of seconds and impeding studies of unstable systems. Both limitations are of equal, fundamental relevance: non-native conditions are of limited pharmacological relevance, and the function of proteins, enzymes and nucleic acids often relies on their interaction kinetics. To overcome these limitations, we have developed applications that involve 'hyperpolarized water' to boost signal intensities in NMR of proteins and nucleic acids. The technique includes four stages: (i) preparation of the biomolecule in partially deuterated buffers, (ii) preparation of 'hyperpolarized' water featuring enhanced 1H NMR signals via cryogenic dynamic nuclear polarization, (iii) sudden melting of the cryogenic pellet and dissolution of the protein or nucleic acid in the hyperpolarized water (enabling spontaneous exchanges of protons between water and target) and (iv) recording signal-amplified NMR spectra targeting either labile 1H or neighboring 15N/13C nuclei in the biomolecule. Water in the ensuing experiments is used as a universal 'hyperpolarization' agent, rendering the approach versatile and applicable to any biomolecule possessing labile hydrogens. Thus, questions can be addressed, ranging from protein and RNA folding problems to resolving structure-function relationships of intrinsically disordered proteins to investigating membrane interactions.
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Affiliation(s)
- Christian Hilty
- Chemistry Department, Texas A&M University, College Station, TX, USA.
| | - Dennis Kurzbach
- Faculty of Chemistry, Institute for Biological Chemistry, University of Vienna, Vienna, Austria.
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
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5
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Heydarnezhad Asl M, Pasban Khelejani F, Bahojb Mahdavi SZ, Emrahi L, Jebelli A, Mokhtarzadeh A. The various regulatory functions of long noncoding RNAs in apoptosis, cell cycle, and cellular senescence. J Cell Biochem 2022; 123:995-1024. [PMID: 35106829 DOI: 10.1002/jcb.30221] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 12/28/2021] [Accepted: 01/11/2022] [Indexed: 12/12/2022]
Abstract
Long noncoding RNAs (lncRNAs) are a group of noncoding cellular RNAs involved in significant biological phenomena such as differentiation, cell development, genomic imprinting, adjusting the enzymatic activity, regulating chromosome conformation, apoptosis, cell cycle, and cellular senescence. The misregulation of lncRNAs interrupting normal biological processes has been implicated in tumor formation and metastasis, resulting in cancer. Apoptosis and cell cycle, two main biological phenomena, are highly conserved and intimately coupled mechanisms. Hence, some cell cycle regulators can influence both programmed cell death and cell division. Apoptosis eliminates defective and unwanted cells, and the cell cycle enables cells to replicate themselves. The improper regulation of apoptosis and cell cycle contributes to numerous disorders such as neurodegenerative and autoimmune diseases, viral infection, anemia, and mainly cancer. Cellular senescence is a tumor-suppressing response initiated by environmental and internal stress factors. This phenomenon has recently attained more attention due to its therapeutic implications in the field of senotherapy. In this review, the regulatory roles of lncRNAs on apoptosis, cell cycle, and senescence will be discussed. First, the role of lncRNAs in mitochondrial dynamics and apoptosis is addressed. Next, the interaction between lncRNAs and caspases, pro/antiapoptotic proteins, and also EGFR/PI3K/PTEN/AKT/mTORC1 signaling pathway will be investigated. Furthermore, the effect of lncRNAs in the cell cycle is surveyed through interaction with cyclins, cdks, p21, and wnt/β-catenin/c-myc pathway. Finally, the function of essential lncRNAs in cellular senescence is mentioned.
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Affiliation(s)
| | - Faezeh Pasban Khelejani
- Department of Cell and Molecular Biology, Faculty of Basic Sciences, University of Maragheh, Maragheh, Iran
| | | | - Leila Emrahi
- Department of Medical Genetics, Faculty of Medical Science, Tarbiat Modares University, Tehran, Iran
| | - Asiyeh Jebelli
- Department of Biological Science, Faculty of Basic Science, Higher Education Institute of Rab-Rashid, Tabriz, Iran.,Tuberculosis and Lung Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ahad Mokhtarzadeh
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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6
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Xu T, Cheng D, Zhao Y, Zhang J, Zhu X, Zhang F, Chen G, Wang Y, Yan X, Robertson GP, Gaddameedhi S, Lazarus P, Wang S, Zhu J. Polymorphic tandem DNA repeats activate the human telomerase reverse transcriptase gene. Proc Natl Acad Sci U S A 2021; 118:e2019043118. [PMID: 34155099 PMCID: PMC8256013 DOI: 10.1073/pnas.2019043118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Multiple independent sequence variants of the hTERT locus have been associated with telomere length and cancer risks in genome-wide association studies. Here, we identified an intronic variable number tandem repeat, VNTR2-1, as an enhancer-like element, which activated hTERT transcription in a cell in a chromatin-dependent manner. VNTR2-1, consisting of 42-bp repeats with an array of enhancer boxes, cooperated with the proximal promoter in the regulation of hTERT transcription by basic helix-loop-helix transcription factors and maintained hTERT expression during embryonic stem-cell differentiation. Genomic deletion of VNTR2-1 in MelJuSo melanoma cells markedly reduced hTERT transcription, leading to telomere shortening, cellular senescence, and impairment of xenograft tumor growth. Interestingly, VNTR2-1 lengths varied widely in human populations; hTERT alleles with shorter VNTR2-1 were underrepresented in African American centenarians, indicating its role in human aging. Therefore, this polymorphic element is likely a missing link in the telomerase regulatory network and a molecular basis for genetic diversities of telomere homeostasis and age-related disease susceptibilities.
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Affiliation(s)
- Tao Xu
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
- College of Life Science, Northeast Forestry University, Harbin 150040, China
| | - De Cheng
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Yuanjun Zhao
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Jinglong Zhang
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Xiaolu Zhu
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Fan Zhang
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Gang Chen
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Yang Wang
- College of Life Science, Northeast Forestry University, Harbin 150040, China
| | - Xiufeng Yan
- College of Life Science, Northeast Forestry University, Harbin 150040, China
- College of Life and Environmental Science, Wenzhou University, Chashan University Town, Wenzhou 325035, China
| | - Gavin P Robertson
- Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Dermatology, Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Surgery, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Shobhan Gaddameedhi
- Center for Human Health and the Environment, Department of Biological Sciences, North Carolina State University, Raleigh, NC 27606
| | - Philip Lazarus
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Shuwen Wang
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Jiyue Zhu
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210;
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7
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Dai L, Yu J. Inchworm stepping of Myc-Max heterodimer protein diffusion along DNA. Biochem Biophys Res Commun 2020; 533:97-103. [PMID: 32933752 DOI: 10.1016/j.bbrc.2020.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 08/02/2020] [Indexed: 02/07/2023]
Abstract
Oncogenic protein Myc serves as a transcription factor to control cell metabolisms. Myc dimerizes via leucine zipper with its associated partner protein Max to form a heterodimer structure, which then binds target DNA sequences to regulate gene transcription. The regulation depends on Myc-Max binding to DNA and searching for target sequences via diffusional motions along DNA. Here, we conduct structure-based molecular dynamics (MD) simulations to investigate the diffusion dynamics of the Myc-Max heterodimer along DNA. We found that the heterodimer protein slides on the DNA in a rotation-uncoupled manner in coarse-grained simulations, as its two helical DNA binding basic regions (BRs) alternate between open and closed conformations via inchworm stepping motions. In such motions, the two BRs of the heterodimer step across the DNA strand one by one, with step sizes reaching about half of a DNA helical pitch length. Atomic MD simulations of the Myc-Max heterodimer in complex with DNA have also been conducted. Hydrogen bond interactions are revealed between the two BRs and two complementary DNA strands, respectively. In the non-specific DNA binding, the BR from Myc shows an onset of stepping on one association DNA strand and starts detaching from the other strand. Overall, our simulation studies suggest that the inchworm stepping motions of the Myc-Max heterodimer can be achieved during the protein diffusion along DNA.
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Affiliation(s)
- Liqiang Dai
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Jin Yu
- Department of Physics and Astronomy, Department of Chemistry, NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, CA, 92697, USA.
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8
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Beaulieu ME, Castillo F, Soucek L. Structural and Biophysical Insights into the Function of the Intrinsically Disordered Myc Oncoprotein. Cells 2020; 9:E1038. [PMID: 32331235 PMCID: PMC7226237 DOI: 10.3390/cells9041038] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 12/13/2022] Open
Abstract
Myc is a transcription factor driving growth and proliferation of cells and involved in the majority of human tumors. Despite a huge body of literature on this critical oncogene, our understanding of the exact molecular determinants and mechanisms that underlie its function is still surprisingly limited. Indubitably though, its crucial and non-redundant role in cancer biology makes it an attractive target. However, achieving successful clinical Myc inhibition has proven challenging so far, as this nuclear protein is an intrinsically disordered polypeptide devoid of any classical ligand binding pockets. Indeed, Myc only adopts a (partially) folded structure in some contexts and upon interacting with some protein partners, for instance when dimerizing with MAX to bind DNA. Here, we review the cumulative knowledge on Myc structure and biophysics and discuss the implications for its biological function and the development of improved Myc inhibitors. We focus this biophysical walkthrough mainly on the basic region helix-loop-helix leucine zipper motif (bHLHLZ), as it has been the principal target for inhibitory approaches so far.
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Affiliation(s)
| | | | - Laura Soucek
- Peptomyc S.L., Edifici Cellex, 08035 Barcelona, Spain; (F.C.); (L.S.)
- Vall d’Hebron Institute of Oncology (VHIO), Edifici Cellex, 08035 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08035 Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, 08035 Bellaterra, Spain
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9
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Li M, Liu Y, Wei Y, Wu C, Meng H, Niu W, Zhou Y, Wang H, Wen Q, Fan S, Li Z, Li X, Zhou J, Cao K, Xiong W, Zeng Z, Li X, Qiu Y, Li G, Zhou M. Zinc-finger protein YY1 suppresses tumor growth of human nasopharyngeal carcinoma by inactivating c-Myc-mediated microRNA-141 transcription. J Biol Chem 2019; 294:6172-6187. [PMID: 30718276 DOI: 10.1074/jbc.ra118.006281] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/18/2019] [Indexed: 12/12/2022] Open
Abstract
Yin Yang 1 (YY1) is a zinc-finger protein that plays critical roles in various biological processes by interacting with DNA and numerous protein partners. YY1 has been reported to play dual biological functions as either an oncogene or tumor suppressor in the development and progression of multiple cancers, but its role in human nasopharyngeal carcinoma (NPC) has not yet been revealed. In this study, we found that YY1 overexpression significantly inhibits cell proliferation and cell-cycle progression from G1 to S and promotes apoptosis in NPC cells. Moreover, we identified YY1 as a component of the c-Myc complex and observed that ectopic expression of YY1 inhibits c-Myc transcriptional activity, as well as the promoter activity and expression of the c-Myc target gene microRNA-141 (miR-141). Furthermore, restoring miR-141 expression could at least partially reverse the inhibitory effect of YY1 on cell proliferation and tumor growth and on the expression of some critical c-Myc targets, such as PTEN/AKT pathway components both in vitro and in vivo We also found that YY1 expression is reduced in NPC tissues, negatively correlates with miR-141 expression and clinical stages in NPC patients, and positively correlates with survival prognosis. Our results reveal a previously unappreciated mechanism in which the YY1/c-Myc/miR-141 axis plays a critical role in NPC progression and may provide some potential and valuable targets for the diagnosis and treatment of NPC.
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Affiliation(s)
- Mengna Li
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013; the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Yukun Liu
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013; the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Yanmei Wei
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013; the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Chunchun Wu
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013; the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Hanbing Meng
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013; the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Weihong Niu
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013; the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Yao Zhou
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013; the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Heran Wang
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013
| | - Qiuyuan Wen
- the Second XiangYa Hospital, Central South University, Changsha, Hunan 410011
| | - Songqing Fan
- the Second XiangYa Hospital, Central South University, Changsha, Hunan 410011
| | - Zheng Li
- the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078; the High Resolution Mass Spectrometry Laboratory of Advanced Research Center, Central South University, Changsha, Hunan 410013
| | - Xiayu Li
- the Third XiangYa Hospital, Central South University, Changsha, Hunan 410008, China
| | - Jianda Zhou
- the Third XiangYa Hospital, Central South University, Changsha, Hunan 410008, China
| | - Ke Cao
- the Third XiangYa Hospital, Central South University, Changsha, Hunan 410008, China
| | - Wei Xiong
- the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Zhaoyang Zeng
- the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Xiaoling Li
- the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Yuanzheng Qiu
- the Department of Otolaryngology Head and Neck Surgery, the Xiangya Hospital, Central South University, Changsha, Hunan 410008
| | - Guiyuan Li
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013; the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078
| | - Ming Zhou
- From the Hunan Cancer Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013; the Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, and Cancer Research Institute, Central South University, Changsha, Hunan 410078.
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10
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Mitra S, Sharma P, Kaur S, Khursheed MA, Gupta S, Chaudhary M, Kurup AJ, Ramachandran R. Dual regulation of lin28a by Myc is necessary during zebrafish retina regeneration. J Cell Biol 2019; 218:489-507. [PMID: 30606747 PMCID: PMC6363449 DOI: 10.1083/jcb.201802113] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 08/31/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023] Open
Abstract
Cellular reprogramming leading to induction of Muller glia-derived progenitor cells (MGPCs) with stem cell characteristics is essential for zebrafish retina regeneration. Although several regeneration-specific genes are characterized, the significance of MGPC-associated Mycb induction remains unknown. Here, we show that early expression of Mycb induces expression of genes like ascl1a, a known activator of lin28a in MGPCs. Notably, mycb is simultaneously activated by Ascl1a and repressed by Insm1a in regenerating retina. Here, we unravel a dual role of Mycb in lin28a expression, both as an activator through Ascl1a in MGPCs and a repressor in combination with Hdac1 in neighboring cells. Myc inhibition reduces the number of MGPCs and abolishes normal regeneration. Myc in collaboration with Hdac1 inhibits her4.1, an effector of Delta-Notch signaling. Further, we also show the repressive role of Delta-Notch signaling on lin28a expression in post-injured retina. Our studies reveal mechanistic understanding of Myc pathway during zebrafish retina regeneration, which could pave way for therapeutic intervention during mammalian retina regeneration.
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Affiliation(s)
- Soumitra Mitra
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Poonam Sharma
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Simran Kaur
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Mohammad Anwar Khursheed
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Shivangi Gupta
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Mansi Chaudhary
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Akshai J Kurup
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Rajesh Ramachandran
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
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11
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Vancraenenbroeck R, Hofmann H. Occupancies in the DNA-Binding Pathways of Intrinsically Disordered Helix-Loop-Helix Leucine-Zipper Proteins. J Phys Chem B 2018; 122:11460-11467. [DOI: 10.1021/acs.jpcb.8b07351] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Renee Vancraenenbroeck
- Department of Structural Biology, Weizmann Institute of Science, Herzl St. 234, 76100 Rehovot, Israel
| | - Hagen Hofmann
- Department of Structural Biology, Weizmann Institute of Science, Herzl St. 234, 76100 Rehovot, Israel
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12
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Macek P, Cliff MJ, Embrey KJ, Holdgate GA, Nissink JWM, Panova S, Waltho JP, Davies RA. Myc phosphorylation in its basic helix-loop-helix region destabilizes transient α-helical structures, disrupting Max and DNA binding. J Biol Chem 2018; 293:9301-9310. [PMID: 29695509 DOI: 10.1074/jbc.ra118.002709] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/16/2018] [Indexed: 01/01/2023] Open
Abstract
Myelocytomatosis proto-oncogene transcription factor (Myc) is an intrinsically disordered protein with critical roles in cellular homeostasis and neoplastic transformation. It is tightly regulated in the cell, with Myc phosphorylation playing a major role. In addition to the well-described tandem phosphorylation of Thr-52 and Ser-62 in the Myc transactivation domain linked to its degradation, P21 (RAC1)-activated kinase 2 (PAK2)-mediated phosphorylation of serine and threonine residues in the C-terminal basic helix-loop-helix leucine zipper (bHLH-LZ) region regulates Myc transcriptional activity. Here we report that PAK2 preferentially phosphorylates Myc twice, at Thr-358 and Ser-373, with only a minor fraction being modified at the previously identified Thr-400 site. For transcriptional activity, Myc binds E-box DNA elements, requiring its heterodimerization with Myc-associated factor X (Max) via the bHLH-LZ regions. Using isothermal calorimetry (ITC), we found that Myc phosphorylation destabilizes this ternary protein-DNA complex by decreasing Myc's affinity for Max by 2 orders of magnitude, suggesting a major effect of phosphorylation on this complex. Phosphomimetic substitutions revealed that Ser-373 dominates the effect on Myc-Max heterodimerization. Moreover, a T400D substitution disrupted Myc's affinity for Max. ITC, NMR, and CD analyses of several Myc variants suggested that the effect of phosphorylation on the Myc-Max interaction is caused by secondary structure disruption during heterodimerization rather than by a change in the structurally disordered state of Myc or by phosphorylation-induced electrostatic repulsion in the heterodimer. Our findings provide critical insights into the effects of PAK2-catalyzed phosphorylation of Myc on its interactions with Max and DNA.
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Affiliation(s)
- Pavel Macek
- From AstraZeneca, IMED Discovery Sciences, Alderley Park SK10 4TG, United Kingdom,
| | - Matthew J Cliff
- the Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Kevin J Embrey
- AstraZeneca, IMED Discovery Sciences, Cambridge CB4 0WG, United Kingdom
| | | | | | - Stanislava Panova
- the Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Jonathan P Waltho
- the Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Rick A Davies
- From AstraZeneca, IMED Discovery Sciences, Alderley Park SK10 4TG, United Kingdom,
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13
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Associating transcription factors and conserved RNA structures with gene regulation in the human brain. Sci Rep 2017; 7:5776. [PMID: 28720872 PMCID: PMC5516038 DOI: 10.1038/s41598-017-06200-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/20/2017] [Indexed: 02/06/2023] Open
Abstract
Anatomical subdivisions of the human brain can be associated with different neuronal functions. This functional diversification is reflected by differences in gene expression. By analyzing post-mortem gene expression data from the Allen Brain Atlas, we investigated the impact of transcription factors (TF) and RNA secondary structures on the regulation of gene expression in the human brain. First, we modeled the expression of a gene as a linear combination of the expression of TFs. We devised an approach to select robust TF-gene interactions and to determine localized contributions to gene expression of TFs. Among the TFs with the most localized contributions, we identified EZH2 in the cerebellum, NR3C1 in the cerebral cortex and SRF in the basal forebrain. Our results suggest that EZH2 is involved in regulating ZIC2 and SHANK1 which have been linked to neurological diseases such as autism spectrum disorder. Second, we associated enriched regulatory elements inside differentially expressed mRNAs with RNA secondary structure motifs. We found a group of purine-uracil repeat RNA secondary structure motifs plus other motifs in neuron related genes such as ACSL4 and ERLIN2.
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14
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Miao Z, Wu L, Lu M, Meng X, Gao B, Qiao X, Zhang W, Xue D. Analysis of the transcriptional regulation of cancer-related genes by aberrant DNA methylation of the cis-regulation sites in the promoter region during hepatocyte carcinogenesis caused by arsenic. Oncotarget 2016; 6:21493-506. [PMID: 26046465 PMCID: PMC4673281 DOI: 10.18632/oncotarget.4085] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 05/11/2015] [Indexed: 12/12/2022] Open
Abstract
Liver is the major organ for arsenic methylation metabolism and may be the potential target of arsenic-induced cancer. In this study, normal human liver cell was treated with arsenic trioxide, and detected using DNA methylation microarray. Some oncogenes, tumor suppressor genes, transcription factors (TF), and tumor-associated genes (TAG) that have aberrant DNA methylation have been identified. However, simple functional studies of genes adjacent to aberrant methylation sites cannot well reflect the regulatory relationship between DNA methylation and gene transcription during the pathogenesis of arsenic-induced liver cancer, whereas a further analysis of the cis-regulatory elements and their trans-acting factors adjacent to DNA methylation can more precisely reflect the relationship between them. MYC and MAX (MYC associated factor X) were found to participating cell cycle through a bioinformatics analysis. Additionally, it was found that the hypomethylation of cis-regulatory sites in the MYC promoter region and the hypermethylation of cis-regulatory sites in the MAX promoter region result in the up-regulation of MYC mRNA expression and the down-regulation of MAX mRNA, which increased the hepatocyte carcinogenesis tendency.
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Affiliation(s)
- Zhuang Miao
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, PR China
| | - Lin Wu
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, PR China
| | - Ming Lu
- Department of Surgery, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Xianzhi Meng
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, PR China
| | - Bo Gao
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, PR China
| | - Xin Qiao
- Department of Surgery, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Weihui Zhang
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, PR China
| | - Dongbo Xue
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, PR China
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15
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Isakova A, Berset Y, Hatzimanikatis V, Deplancke B. Quantification of Cooperativity in Heterodimer-DNA Binding Improves the Accuracy of Binding Specificity Models. J Biol Chem 2016; 291:10293-306. [PMID: 26912662 PMCID: PMC4858977 DOI: 10.1074/jbc.m115.691154] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 02/18/2016] [Indexed: 12/31/2022] Open
Abstract
Many transcription factors (TFs) have the ability to cooperate on DNA elements as heterodimers. Despite the significance of TF heterodimerization for gene regulation, a quantitative understanding of cooperativity between various TF dimer partners and its impact on heterodimer DNA binding specificity models is still lacking. Here, we used a novel integrative approach, combining microfluidics-steered measurements of dimer-DNA assembly with mechanistic modeling of the implicated protein-protein-DNA interactions to quantitatively interrogate the cooperative DNA binding behavior of the adipogenic peroxisome proliferator-activated receptor γ (PPARγ):retinoid X receptor α (RXRα) heterodimer. Using the high throughput MITOMI (mechanically induced trapping of molecular interactions) platform, we derived equilibrium DNA binding data for PPARγ, RXRα, as well as the PPARγ:RXRα heterodimer to more than 300 target DNA sites and variants thereof. We then quantified cooperativity underlying heterodimer-DNA binding and derived an integrative heterodimer DNA binding constant. Using this cooperativity-inclusive constant, we were able to build a heterodimer-DNA binding specificity model that has superior predictive power than the one based on a regular one-site equilibrium. Our data further revealed that individual nucleotide substitutions within the target site affect the extent of cooperativity in PPARγ:RXRα-DNA binding. Our study therefore emphasizes the importance of assessing cooperativity when generating DNA binding specificity models for heterodimers.
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Affiliation(s)
- Alina Isakova
- From the Institute of Bioengineering, Swiss Institute of Bioinformatics (SIB), CH-1015 Lausanne, Switzerland
| | - Yves Berset
- From the Institute of Bioengineering, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, and Swiss Institute of Bioinformatics (SIB), CH-1015 Lausanne, Switzerland
| | - Vassily Hatzimanikatis
- Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, and Swiss Institute of Bioinformatics (SIB), CH-1015 Lausanne, Switzerland
| | - Bart Deplancke
- From the Institute of Bioengineering, Swiss Institute of Bioinformatics (SIB), CH-1015 Lausanne, Switzerland
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16
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Zheng X, Bi C, Li Z, Podariu M, Hage DS. Analytical methods for kinetic studies of biological interactions: A review. J Pharm Biomed Anal 2015; 113:163-80. [PMID: 25700721 PMCID: PMC4516701 DOI: 10.1016/j.jpba.2015.01.042] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/16/2015] [Accepted: 01/19/2015] [Indexed: 01/13/2023]
Abstract
The rates at which biological interactions occur can provide important information concerning the mechanism and behavior of these processes in living systems. This review discusses several analytical methods that can be used to examine the kinetics of biological interactions. These techniques include common or traditional methods such as stopped-flow analysis and surface plasmon resonance spectroscopy, as well as alternative methods based on affinity chromatography and capillary electrophoresis. The general principles and theory behind these approaches are examined, and it is shown how each technique can be utilized to provide information on the kinetics of biological interactions. Examples of applications are also given for each method. In addition, a discussion is provided on the relative advantages or potential limitations of each technique regarding its use in kinetic studies.
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Affiliation(s)
- Xiwei Zheng
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588, USA
| | - Cong Bi
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588, USA
| | - Zhao Li
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588, USA
| | - Maria Podariu
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588, USA
| | - David S Hage
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588, USA.
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17
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Yoo YS, Park S, Gwak J, Ju BG, Oh S. Involvement of transcription repressor Snail in the regulation of human telomerase reverse transcriptase (hTERT) by transforming growth factor-β. Biochem Biophys Res Commun 2015; 465:131-6. [PMID: 26235880 DOI: 10.1016/j.bbrc.2015.07.146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 07/29/2015] [Indexed: 12/28/2022]
Abstract
Human telomerase reverse transcriptase (hTERT), a catalytic subunit of telomerase, is the primary determinant for telomerase enzyme activity, which has been associated with cellular immortality. Expression of the hTERT gene is regulated by various extracellular (external) stimuli and is aberrantly up-regulated in more than 90% of cancers. Here we show that hTERT gene expression was repressed in response to transforming growth factor-β (TGF-β) by a mechanism dependent on transcription factors Snail and c-Myc. TGF-β activated Snail and down-regulated c-Myc gene expression. In addition, ectopic expression of Snail strongly inhibited hTERT promoter activity, although co-expression of c-Myc abrogated this effect. Chromatin immunoprecipitation (ChIP) analysis revealed that TGF-β decreased c-Myc occupancy and dramatically increased recruitment of Snail to the E-box motifs of the hTERT promoter, thereby repressing hTERT expression. Our findings suggest a dynamic alteration in hTERT promoter occupancy by Snail and c-Myc is the mechanistic basis for TGF-β-mediated regulation of hTERT.
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Affiliation(s)
- Young-Sun Yoo
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul 136-702, Republic of Korea
| | - Seoyoung Park
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul 136-702, Republic of Korea
| | - Jungsug Gwak
- Research Institute for Basic Science, Sogang University, 35 Baekbeom-ro (Sinsu-dong), Mapo-gu, Seoul 121-742, Republic of Korea
| | - Bong Gun Ju
- Research Institute for Basic Science, Sogang University, 35 Baekbeom-ro (Sinsu-dong), Mapo-gu, Seoul 121-742, Republic of Korea
| | - Sangtaek Oh
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul 136-702, Republic of Korea.
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18
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Sammak S, Zinzalla G. Targeting protein-protein interactions (PPIs) of transcription factors: Challenges of intrinsically disordered proteins (IDPs) and regions (IDRs). PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 119:41-6. [PMID: 26126425 DOI: 10.1016/j.pbiomolbio.2015.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 06/23/2015] [Accepted: 06/25/2015] [Indexed: 12/26/2022]
Abstract
In this review we discuss recent progress in targeting the protein-protein interactions made by oncogenic transcription factors. We particularly focus on the challenges posed by the prevalence of intrinsically disordered regions in this class of protein and the strategies being used to overcome them.
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Affiliation(s)
- Susan Sammak
- Department of Microbiology, Cell and Tumour Biology, and Science for Life Laboratory, Karolinska Institutet, Tomtebodavägen 23A, Stockholm 171 65, Sweden
| | - Giovanna Zinzalla
- Department of Microbiology, Cell and Tumour Biology, and Science for Life Laboratory, Karolinska Institutet, Tomtebodavägen 23A, Stockholm 171 65, Sweden.
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19
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Luo Y, North JA, Poirier MG. Single molecule fluorescence methodologies for investigating transcription factor binding kinetics to nucleosomes and DNA. Methods 2014; 70:108-18. [PMID: 25304387 DOI: 10.1016/j.ymeth.2014.09.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 09/03/2014] [Accepted: 09/30/2014] [Indexed: 11/20/2022] Open
Abstract
Site specific DNA binding complexes must bind their DNA target sites and then reside there for a sufficient amount of time for proper regulation of DNA processing including transcription, replication and DNA repair. In eukaryotes, the occupancy of DNA binding complexes at their target sites is regulated by chromatin structure and dynamics. Methodologies that probe both the binding and dissociation kinetics of DNA binding proteins with naked and nucleosomal DNA are essential for understanding the mechanisms by which these complexes function. Here, we describe single-molecule fluorescence methodologies for quantifying the binding and dissociation kinetics of transcription factors at a target site within DNA, nucleosomes and nucleosome arrays. This approach allowed for the unexpected observation that nucleosomes impact not only binding but also dissociation kinetics of transcription factors and is well-suited for the investigation of numerous DNA processing complexes that directly interact with DNA organized into chromatin.
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Affiliation(s)
- Yi Luo
- Department of Physics, The Ohio State University, Columbus, OH 43210-1117, United States; Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210-1117, United States
| | - Justin A North
- Department of Physics, The Ohio State University, Columbus, OH 43210-1117, United States
| | - Michael G Poirier
- Department of Physics, The Ohio State University, Columbus, OH 43210-1117, United States; Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210-1117, United States.
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20
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Suda N, Itoh T, Nakato R, Shirakawa D, Bando M, Katou Y, Kataoka K, Shirahige K, Tickle C, Tanaka M. Dimeric combinations of MafB, cFos and cJun control the apoptosis-survival balance in limb morphogenesis. Development 2014; 141:2885-94. [DOI: 10.1242/dev.099150] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Apoptosis is an important mechanism for sculpting morphology. However, the molecular cascades that control apoptosis in developing limb buds remain largely unclear. Here, we show that MafB was specifically expressed in apoptotic regions of chick limb buds, and MafB/cFos heterodimers repressed apoptosis, whereas MafB/cJun heterodimers promoted apoptosis for sculpting the shape of the limbs. Chromatin immunoprecipitation sequencing in chick limb buds identified potential target genes and regulatory elements controlled by Maf and Jun. Functional analyses revealed that expression of p63 and p73, key components known to arrest the cell cycle, was directly activated by MafB and cJun. Our data suggest that dimeric combinations of MafB, cFos and cJun in developing chick limb buds control the number of apoptotic cells, and that MafB/cJun heterodimers lead to apoptosis via activation of p63 and p73.
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Affiliation(s)
- Natsuno Suda
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, B-17, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
| | - Takehiko Itoh
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, B-34, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
| | - Ryuichiro Nakato
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Daisuke Shirakawa
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, B-17, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
| | - Masashige Bando
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Yuki Katou
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Kohsuke Kataoka
- Graduate School of Medical Life Sciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Katsuhiko Shirahige
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Cheryll Tickle
- Department of Biology and Biochemistry, University of Bath, Claverton Down Road, Bath BA2 7AY, UK
| | - Mikiko Tanaka
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, B-17, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
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21
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Myc and its interactors take shape. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:469-83. [PMID: 24933113 DOI: 10.1016/j.bbagrm.2014.06.002] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 06/03/2014] [Accepted: 06/04/2014] [Indexed: 12/11/2022]
Abstract
The Myc oncoprotein is a key contributor to the development of many human cancers. As such, understanding its molecular activities and biological functions has been a field of active research since its discovery more than three decades ago. Genome-wide studies have revealed Myc to be a global regulator of gene expression. The identification of its DNA-binding partner protein, Max, launched an area of extensive research into both the protein-protein interactions and protein structure of Myc. In this review, we highlight key insights with respect to Myc interactors and protein structure that contribute to the understanding of Myc's roles in transcriptional regulation and cancer. Structural analyses of Myc show many critical regions with transient structures that mediate protein interactions and biological functions. Interactors, such as Max, TRRAP, and PTEF-b, provide mechanistic insight into Myc's transcriptional activities, while others, such as ubiquitin ligases, regulate the Myc protein itself. It is appreciated that Myc possesses a large interactome, yet the functional relevance of many interactors remains unknown. Here, we discuss future research trends that embrace advances in genome-wide and proteome-wide approaches to systematically elucidate mechanisms of Myc action. This article is part of a Special Issue entitled: Myc proteins in cell biology and pathology.
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22
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Guo J, Li T, Schipper J, Nilson KA, Fordjour FK, Cooper JJ, Gordân R, Price DH. Sequence specificity incompletely defines the genome-wide occupancy of Myc. Genome Biol 2014; 15:482. [PMID: 25287278 PMCID: PMC4242493 DOI: 10.1186/s13059-014-0482-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/22/2014] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The Myc-Max heterodimer is a transcription factor that regulates expression of a large number of genes. Genome occupancy of Myc-Max is thought to be driven by Enhancer box (E-box) DNA elements, CACGTG or variants, to which the heterodimer binds in vitro. RESULTS By analyzing ChIP-Seq datasets, we demonstrate that the positions occupied by Myc-Max across the human genome correlate with the RNA polymerase II, Pol II, transcription machinery significantly better than with E-boxes. Metagene analyses show that in promoter regions, Myc is uniformly positioned about 100 bp upstream of essentially all promoter proximal paused polymerases with Max about 15 bp upstream of Myc. We re-evaluate the DNA binding properties of full length Myc-Max proteins. Electrophoretic mobility shift assay results demonstrate Myc-Max heterodimers display significant sequence preference, but have high affinity for any DNA. Quantification of the relative affinities of Myc-Max for all possible 8-mers using universal protein-binding microarray assays shows that sequences surrounding core 6-mers significantly affect binding. Compared to the in vitro sequence preferences,Myc-Max genomic occupancy measured by ChIP-Seq is largely, although not completely, independent of sequence specificity. CONCLUSIONS We quantified the affinity of Myc-Max to all possible 8-mers and compared this with the sites of Myc binding across the human genome. Our results indicate that the genomic occupancy of Myc cannot be explained by its intrinsic DNA specificity and suggest that the transcription machinery and associated promoter accessibility play a predominant role in Myc recruitment.
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Affiliation(s)
- Jiannan Guo
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
| | - Tiandao Li
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
- />The Genome Institute, Washington University in St. Louis, St. Louis, MO 63108 USA
| | - Joshua Schipper
- />Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708 USA
| | - Kyle A Nilson
- />Molecular and Cellular Biology Program, University of Iowa, Iowa City, IA 52242 USA
| | - Francis K Fordjour
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
| | - Jeffrey J Cooper
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
| | - Raluca Gordân
- />Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708 USA
| | - David H Price
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
- />Molecular and Cellular Biology Program, University of Iowa, Iowa City, IA 52242 USA
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23
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The roles of HLH transcription factors in epithelial mesenchymal transition and multiple molecular mechanisms. Clin Exp Metastasis 2013; 31:367-77. [PMID: 24158354 DOI: 10.1007/s10585-013-9621-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 10/10/2013] [Indexed: 02/06/2023]
Abstract
Epithelial-to-mesenchymal transition (EMT) is presently recognized as an important event and the initiating stage for tumor invasion and metastasis. Several EMT inducers have been identified, among which the big family of helix-loop-helix (HLH) transcription factors are rising as a novel and promising family of proteins in EMT mediation, such as Twist1, Twist2, E47, and HIFs, etc. Due to the variety and complexities of HLH members, the pathways and mechanisms they employ to promote EMT are also complex and characteristic. In this review, we will discuss the roles of various HLH proteins in the regulation and sustenance of the EMT and multiple cellular mechanisms, attempting to provide a novel and broadened view towards the link between HLH proteins and EMT.
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24
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Lin CY, Lovén J, Rahl PB, Paranal RM, Burge CB, Bradner JE, Lee TI, Young RA. Transcriptional amplification in tumor cells with elevated c-Myc. Cell 2012; 151:56-67. [PMID: 23021215 DOI: 10.1016/j.cell.2012.08.026] [Citation(s) in RCA: 1133] [Impact Index Per Article: 94.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/29/2012] [Accepted: 08/08/2012] [Indexed: 12/12/2022]
Abstract
Elevated expression of the c-Myc transcription factor occurs frequently in human cancers and is associated with tumor aggression and poor clinical outcome. The effect of high levels of c-Myc on global gene regulation is poorly understood but is widely thought to involve newly activated or repressed "Myc target genes." We report here that in tumor cells expressing high levels of c-Myc the transcription factor accumulates in the promoter regions of active genes and causes transcriptional amplification, producing increased levels of transcripts within the cell's gene expression program. Thus, rather than binding and regulating a new set of genes, c-Myc amplifies the output of the existing gene expression program. These results provide an explanation for the diverse effects of oncogenic c-Myc on gene expression in different tumor cells and suggest that transcriptional amplification reduces rate-limiting constraints for tumor cell growth and proliferation.
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Affiliation(s)
- Charles Y Lin
- Whitehead Institute for Biomedical Research, Cambridge Center, MA 02142, USA
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25
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Verzele D, Madder A. Synthetic Progress in cMyc-Max Oncoprotein Miniaturization: Semi-Online Monitoring Gives Solid-Phase Access to Hydrophobic b(-HLH-)ZIP Peptidosteroid Tweezers. European J Org Chem 2012. [DOI: 10.1002/ejoc.201201235] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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26
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Matsuura T, Hosoda K, Ichihashi N, Kazuta Y, Yomo T. Kinetic analysis of β-galactosidase and β-glucuronidase tetramerization coupled with protein translation. J Biol Chem 2011; 286:22028-34. [PMID: 21531724 DOI: 10.1074/jbc.m111.240168] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Both β-galactosidase (GAL) and β-glucuronidase (GUS) are tetrameric enzymes used widely as reporter proteins. However, little is known about the folding and assembly of these enzymes. Although the refolding kinetics of GAL from a denatured enzyme have been reported, it is not known how the kinetics differ when coupled with a protein translation reaction. Elucidating the assembly kinetics of GAL and GUS when coupled with protein translation will illustrate the differences between these two reporter proteins and also the assembly process under conditions more relevant to those in vivo. In this study, we used an in vitro translation/transcription system to synthesize GAL and GUS, measured the time development of the activity and oligomerization state of these enzymes, and determined the rate constants of the monomer to tetramer assembly process. We found that at similar concentrations, GAL assembles into tetramers faster than GUS. The rate constant of monomer to dimer assembly of GAL was 50-fold faster when coupled with protein translation than that of refolding from the denatured state. Furthermore, GAL synthesis was found to lack the rate-limiting step in the assembly process, whereas GUS has two rate-limiting steps: monomer to dimer assembly and dimer to tetramer assembly. The consequence of these differences when used as reporter proteins is discussed.
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Affiliation(s)
- Tomoaki Matsuura
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
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