1
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Dror I, Chitiashvili T, Tan SYX, Cano CT, Sahakyan A, Markaki Y, Chronis C, Collier AJ, Deng W, Liang G, Sun Y, Afasizheva A, Miller J, Xiao W, Black DL, Ding F, Plath K. XIST directly regulates X-linked and autosomal genes in naive human pluripotent cells. Cell 2024; 187:110-129.e31. [PMID: 38181737 PMCID: PMC10783549 DOI: 10.1016/j.cell.2023.11.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/01/2023] [Accepted: 11/28/2023] [Indexed: 01/07/2024]
Abstract
X chromosome inactivation (XCI) serves as a paradigm for RNA-mediated regulation of gene expression, wherein the long non-coding RNA XIST spreads across the X chromosome in cis to mediate gene silencing chromosome-wide. In female naive human pluripotent stem cells (hPSCs), XIST is in a dispersed configuration, and XCI does not occur, raising questions about XIST's function. We found that XIST spreads across the X chromosome and induces dampening of X-linked gene expression in naive hPSCs. Surprisingly, XIST also targets specific autosomal regions, where it induces repressive chromatin changes and gene expression dampening. Thereby, XIST equalizes X-linked gene dosage between male and female cells while inducing differences in autosomes. The dispersed Xist configuration and autosomal localization also occur transiently during XCI initiation in mouse PSCs. Together, our study identifies XIST as the regulator of X chromosome dampening, uncovers an evolutionarily conserved trans-acting role of XIST/Xist, and reveals a correlation between XIST/Xist dispersal and autosomal targeting.
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Affiliation(s)
- Iris Dror
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tsotne Chitiashvili
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Shawn Y X Tan
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Clara T Cano
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Anna Sahakyan
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yolanda Markaki
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute for Structural and Chemical Biology & Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Constantinos Chronis
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Amanda J Collier
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Weixian Deng
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Guohao Liang
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA
| | - Yu Sun
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Anna Afasizheva
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jarrett Miller
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Wen Xiao
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Douglas L Black
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Fangyuan Ding
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA; Department of Developmental and Cell Biology, Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Kathrin Plath
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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2
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Elkoshi N, Parikh S, Malcov-Brog H, Parikh R, Manich P, Netti F, Maliah A, Elkoshi H, Haj M, Rippin I, Frand J, Perluk T, Haiat-Factor R, Golan T, Regev-Rudzki N, Kiper E, Brenner R, Gonen P, Dror I, Levi H, Hameiri O, Cohen-Gulkar M, Eldar-Finkelman H, Ast G, Nizri E, Ziv Y, Elkon R, Khaled M, Ebenstein Y, Shiloh Y, Levy C. Ataxia Telangiectasia Mutated Signaling Delays Skin Pigmentation upon UV Exposure by Mediating MITF Function toward DNA Repair Mode. J Invest Dermatol 2023; 143:2494-2506.e4. [PMID: 37236596 DOI: 10.1016/j.jid.2023.03.1686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 02/24/2023] [Accepted: 03/02/2023] [Indexed: 05/28/2023]
Abstract
Skin pigmentation is paused after sun exposure; however, the mechanism behind this pausing is unknown. In this study, we found that the UVB-induced DNA repair system, led by the ataxia telangiectasia mutated (ATM) protein kinase, represses MITF transcriptional activity of pigmentation genes while placing MITF in DNA repair mode, thus directly inhibiting pigment production. Phosphoproteomics analysis revealed ATM to be the most significantly enriched pathway among all UVB-induced DNA repair systems. ATM inhibition in mouse or human skin, either genetically or chemically, induces pigmentation. Upon UVB exposure, MITF transcriptional activation is blocked owing to ATM-dependent phosphorylation of MITF on S414, which modifies MITF activity and interactome toward DNA repair, including binding to TRIM28 and RBBP4. Accordingly, MITF genome occupancy is enriched in sites of high DNA damage that are likely repaired. This suggests that ATM harnesses the pigmentation key activator for the necessary rapid, efficient DNA repair, thus optimizing the chances of the cell surviving. Data are available from ProteomeXchange with the identifier PXD041121.
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Affiliation(s)
- Nadav Elkoshi
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shivang Parikh
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hagar Malcov-Brog
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Roma Parikh
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Paulee Manich
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Francesca Netti
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Avishai Maliah
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hana Elkoshi
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Majd Haj
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ido Rippin
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Jacob Frand
- Department of Plastic and Reconstructive Surgery, Edith Wolfson Medical Center, Holon, Israel
| | - Tomer Perluk
- Department of Plastic and Reconstructive Surgery, Edith Wolfson Medical Center, Holon, Israel
| | - Rivi Haiat-Factor
- Department of Plastic and Reconstructive Surgery, Edith Wolfson Medical Center, Holon, Israel
| | - Tamar Golan
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Neta Regev-Rudzki
- Department of Biomolecular Sciences, Faculty of Biochemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Edo Kiper
- Department of Biomolecular Sciences, Faculty of Biochemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Ronen Brenner
- Institute of Oncology, Edith Wolfson Medical Center, Holon, Israel
| | - Pinchas Gonen
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Iris Dror
- Department of Biological Chemistry, University of California Loss Angeles School of Medicine, Los Angeles, California, USA
| | - Hagai Levi
- The Blavatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel
| | - Ofir Hameiri
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Mazal Cohen-Gulkar
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hagit Eldar-Finkelman
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Gil Ast
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eran Nizri
- Department of Dermatology, Tel Aviv Sourasky Medical Center Ichilov, Tel Aviv, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yael Ziv
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Rani Elkon
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Mehdi Khaled
- INSERM 1186, Gustave Roussy, Université Paris-Saclay, Villejuif, France
| | - Yuval Ebenstein
- School of Chemistry, Center for Nanoscience and Nanotechnology, Center for Light-Matter Interaction, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yosef Shiloh
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Carmit Levy
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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3
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Chitiashvili T, Hsu FM, Dror I, Plath K, Clark A. FGFR3 is expressed by human primordial germ cells and is repressed after meiotic initiation to form primordial oocytes. Stem Cell Reports 2022; 17:1268-1278. [PMID: 35594860 PMCID: PMC9214056 DOI: 10.1016/j.stemcr.2022.04.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 04/15/2022] [Accepted: 04/19/2022] [Indexed: 01/19/2023] Open
Abstract
Human germ cell development is a highly regulated process beginning soon after embryo implantation with the specification of primordial germ cells (PGCs) and ending in adulthood with the differentiation of gametes. Here, we show that fibroblast growth factor receptor 3 (FGFR3) is expressed by human PGCs during the first and second trimester, becoming repressed as PGCs differentiate into primordial oocytes. Using fluorescence-activated cell sorting (FACS) with antibodies that recognize FGFR3 followed by single-cell RNA sequencing, we show that isolating FGFR3-positive cells enriches for human PGCs. Taken together, FGFR3 could be used in future studies as a strategy to identify maturing PGCs in vitro.
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Affiliation(s)
- Tsotne Chitiashvili
- Molecular Cell and Developmental Biology Department, University of California Los Angeles, Los Angeles, CA, USA,Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA,Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Fei-man Hsu
- Molecular Cell and Developmental Biology Department, University of California Los Angeles, Los Angeles, CA, USA
| | - Iris Dror
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Kathrin Plath
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA,Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, USA,Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA,Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA, USA
| | - Amander Clark
- Molecular Cell and Developmental Biology Department, University of California Los Angeles, Los Angeles, CA, USA,Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, USA,Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA,Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA, USA,Corresponding author
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4
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Malejko J, Godlewska-Żyłkiewicz B, Vanek T, Landa P, Nath J, Dror I, Berkowitz B. Uptake, translocation, weathering and speciation of gold nanoparticles in potato, radish, carrot and lettuce crops. J Hazard Mater 2021; 418:126219. [PMID: 34102370 DOI: 10.1016/j.jhazmat.2021.126219] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/06/2021] [Accepted: 05/23/2021] [Indexed: 06/12/2023]
Abstract
Extensive use of nanomaterials in agriculture will inevitably lead to their release to the environment in significant loads. Thus, understanding the fate of nanoparticles in the soil-plant environment, and potential presence and consequent implication of nanoparticles in food and feed products, is required. We study plant uptake of gold nanoparticles from soil, and their distribution, translocation and speciation (in terms of particle size change and release of ionic Au) in the different plant tissues of four important crops (potato, radish, carrot and lettuce). Our new analytical protocol and experiments show the feasibility of determining the presence, concentration and distribution of nanoparticles in different plant parts, which differ from plant to plant. Critically, we identify the evident capacity of plants to break down (or substantially change the properties of) nanoparticles in the rhizosphere prior to uptake, as well as the evident capacity of plants to reorganize ionic metals as nanoparticles in their tissues. This could lead to nanoparticle exposure through consumption of crops.
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Affiliation(s)
- J Malejko
- Department of Analytical Chemistry, Faculty of Chemistry, University of Bialystok, K. Ciołkowskiego 1K, 15-245 Białystok, Poland
| | - B Godlewska-Żyłkiewicz
- Department of Analytical Chemistry, Faculty of Chemistry, University of Bialystok, K. Ciołkowskiego 1K, 15-245 Białystok, Poland
| | - T Vanek
- Laboratory of Plant Biotechnologies, Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojova 263, 165 02 Prague 6, Czech Republic
| | - P Landa
- Laboratory of Plant Biotechnologies, Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojova 263, 165 02 Prague 6, Czech Republic
| | - J Nath
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - I Dror
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel.
| | - B Berkowitz
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
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5
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Malcov-Brog H, Alpert A, Golan T, Parikh S, Nordlinger A, Netti F, Sheinboim D, Dror I, Thomas L, Cosson C, Gonen P, Stanevsky Y, Brenner R, Perluk T, Frand J, Elgavish S, Nevo Y, Rahat D, Tabach Y, Khaled M, Shen-Orr SS, Levy C. UV-Protection Timer Controls Linkage between Stress and Pigmentation Skin Protection Systems. Mol Cell 2018; 72:444-456.e7. [PMID: 30401431 PMCID: PMC6224604 DOI: 10.1016/j.molcel.2018.09.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 08/15/2018] [Accepted: 09/18/2018] [Indexed: 11/25/2022]
Abstract
Skin sun exposure induces two protection programs: stress responses and pigmentation, the former within minutes and the latter only hours afterward. Although serving the same physiological purpose, it is not known whether and how these programs are coordinated. Here, we report that UVB exposure every other day induces significantly more skin pigmentation than the higher frequency of daily exposure, without an associated increase in stress responses. Using mathematical modeling and empirical studies, we show that the melanocyte master regulator, MITF, serves to synchronize stress responses and pigmentation and, furthermore, functions as a UV-protection timer via damped oscillatory dynamics, thereby conferring a trade-off between the two programs. MITF oscillations are controlled by multiple negative regulatory loops, one at the transcriptional level involving HIF1α and another post-transcriptional loop involving microRNA-148a. These findings support trait linkage between the two skin protection programs, which, we speculate, arose during furless skin evolution to minimize skin damage. UV exposure frequency reveals a trade-off between skin protection programs MITF dynamics synchronize skin stress responses and pigmentation MITF serves as a UV-protection timer Two negative regulatory loops involving miR-148a and HIF1α underlie MITF dynamics
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Affiliation(s)
- Hagar Malcov-Brog
- Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ayelet Alpert
- Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Tamar Golan
- Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shivang Parikh
- Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Alice Nordlinger
- INSERM U1186, Gustave Roussy Cancer Center, Université Paris-Saclay, Villejuif 94805, France
| | - Francesca Netti
- Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Danna Sheinboim
- Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Iris Dror
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Laetitia Thomas
- INSERM U1186, Gustave Roussy Cancer Center, Université Paris-Saclay, Villejuif 94805, France
| | - Camille Cosson
- INSERM U1186, Gustave Roussy Cancer Center, Université Paris-Saclay, Villejuif 94805, France
| | - Pinchas Gonen
- Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | | | | | | | - Jacob Frand
- E. Wolfson Medical Center, Holon 58100, Israel
| | - Sharona Elgavish
- Bioinformatics Unit of the I-CORE Computation Center, Hebrew University, Jerusalem 91120, Israel
| | - Yuval Nevo
- Bioinformatics Unit of the I-CORE Computation Center, Hebrew University, Jerusalem 91120, Israel
| | - Dolev Rahat
- Department of Developmental Biology and Cancer Research, Hadassah Medical School, Hebrew University, Jerusalem 91120, Israel
| | - Yuval Tabach
- Department of Developmental Biology and Cancer Research, Hadassah Medical School, Hebrew University, Jerusalem 91120, Israel
| | - Mehdi Khaled
- INSERM U1186, Gustave Roussy Cancer Center, Université Paris-Saclay, Villejuif 94805, France.
| | - Shai S Shen-Orr
- Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
| | - Carmit Levy
- Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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6
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Schöne S, Jurk M, Helabad MB, Dror I, Lebars I, Kieffer B, Imhof P, Rohs R, Vingron M, Thomas-Chollier M, Meijsing SH. Corrigendum: Sequences flanking the core-binding site modulate glucocorticoid receptor structure and activity. Nat Commun 2016; 7:13784. [PMID: 27873998 PMCID: PMC5121421 DOI: 10.1038/ncomms13784] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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7
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Schöne S, Jurk M, Helabad MB, Dror I, Lebars I, Kieffer B, Imhof P, Rohs R, Vingron M, Thomas-Chollier M, Meijsing SH. Sequences flanking the core-binding site modulate glucocorticoid receptor structure and activity. Nat Commun 2016; 7:12621. [PMID: 27581526 PMCID: PMC5025757 DOI: 10.1038/ncomms12621] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/18/2016] [Indexed: 02/07/2023] Open
Abstract
The glucocorticoid receptor (GR) binds as a homodimer to genomic response elements, which have particular sequence and shape characteristics. Here we show that the nucleotides directly flanking the core-binding site, differ depending on the strength of GR-dependent activation of nearby genes. Our study indicates that these flanking nucleotides change the three-dimensional structure of the DNA-binding site, the DNA-binding domain of GR and the quaternary structure of the dimeric complex. Functional studies in a defined genomic context show that sequence-induced changes in GR activity cannot be explained by differences in GR occupancy. Rather, mutating the dimerization interface mitigates DNA-induced changes in both activity and structure, arguing for a role of DNA-induced structural changes in modulating GR activity. Together, our study shows that DNA sequence identity of genomic binding sites modulates GR activity downstream of binding, which may play a role in achieving regulatory specificity towards individual target genes.
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Affiliation(s)
- Stefanie Schöne
- Max Planck Institute for Molecular Genetics, Department of Computational Molecular Biology, Ihnestrasse 63-73, Berlin 14195, Germany
| | - Marcel Jurk
- Max Planck Institute for Molecular Genetics, Department of Computational Molecular Biology, Ihnestrasse 63-73, Berlin 14195, Germany
| | | | - Iris Dror
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Isabelle Lebars
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Biologie Structurale, Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institute National de la Santé et de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, 67404 Illkirch Cedex, France
| | - Bruno Kieffer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Biologie Structurale, Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institute National de la Santé et de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, 67404 Illkirch Cedex, France
| | - Petra Imhof
- Institute of Theoretical Physics, Free University Berlin, 14195 Berlin, Germany
| | - Remo Rohs
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Martin Vingron
- Max Planck Institute for Molecular Genetics, Department of Computational Molecular Biology, Ihnestrasse 63-73, Berlin 14195, Germany
| | - Morgane Thomas-Chollier
- Institut de Biologie de l'Ecole Normale Supérieure, Institut National de la Santé et de la Recherche Médicale, U1024, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8197, F-75005 Paris, France
| | - Sebastiaan H Meijsing
- Max Planck Institute for Molecular Genetics, Department of Computational Molecular Biology, Ihnestrasse 63-73, Berlin 14195, Germany
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8
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Sheinboim D, Maza I, Dror I, Hanna J, Levy C. Pluripotent genes role in normal melanocyte lineage commitment and malignant transformation. Eur J Cancer 2016. [DOI: 10.1016/s0959-8049(16)61386-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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9
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Abstract
Transcription factors (TFs) have to find their binding sites, which are distributed throughout the genome. Facilitated diffusion is currently the most widely accepted model for this search process. Based on this model the TF alternates between one-dimensional sliding along the DNA, and three-dimensional bulk diffusion. In this view, the non-specific associations between the proteins and the DNA play a major role in the search dynamics. However, little is known about how the DNA properties around the motif contribute to the search. Accumulating evidence showing that TF binding sites are embedded within a unique environment, specific to each TF, leads to the hypothesis that the search process is facilitated by favorable DNA features that help to improve the search efficiency. Here, we review the field and present the hypothesis that TF-DNA recognition is dictated not only by the motif, but is also influenced by the environment in which the motif resides.
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Affiliation(s)
- Iris Dror
- Department of Biology, Technion - Israel Institute of Technology, Technion City, Haifa, Israel.,Departments of Biological Sciences, Chemistry, Physics, and Computer Science, Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA, USA
| | - Remo Rohs
- Departments of Biological Sciences, Chemistry, Physics, and Computer Science, Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA, USA
| | - Yael Mandel-Gutfreund
- Department of Biology, Technion - Israel Institute of Technology, Technion City, Haifa, Israel
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10
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Dror I, Golan T, Levy C, Rohs R, Mandel-Gutfreund Y. A widespread role of the motif environment in transcription factor binding across diverse protein families. Genome Res 2015; 25:1268-80. [PMID: 26160164 PMCID: PMC4561487 DOI: 10.1101/gr.184671.114] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 07/08/2015] [Indexed: 12/12/2022]
Abstract
Transcriptional regulation requires the binding of transcription factors (TFs) to short sequence-specific DNA motifs, usually located at the gene regulatory regions. Interestingly, based on a vast amount of data accumulated from genomic assays, it has been shown that only a small fraction of all potential binding sites containing the consensus motif of a given TF actually bind the protein. Recent in vitro binding assays, which exclude the effects of the cellular environment, also demonstrate selective TF binding. An intriguing conjecture is that the surroundings of cognate binding sites have unique characteristics that distinguish them from other sequences containing a similar motif that are not bound by the TF. To test this hypothesis, we conducted a comprehensive analysis of the sequence and DNA shape features surrounding the core-binding sites of 239 and 56 TFs extracted from in vitro HT-SELEX binding assays and in vivo ChIP-seq data, respectively. Comparing the nucleotide content of the regions around the TF-bound sites to the counterpart unbound regions containing the same consensus motifs revealed significant differences that extend far beyond the core-binding site. Specifically, the environment of the bound motifs demonstrated unique sequence compositions, DNA shape features, and overall high similarity to the core-binding motif. Notably, the regions around the binding sites of TFs that belong to the same TF families exhibited similar features, with high agreement between the in vitro and in vivo data sets. We propose that these unique features assist in guiding TFs to their cognate binding sites.
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Affiliation(s)
- Iris Dror
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel; Molecular and Computational Biology Program, Departments of Biological Sciences, Chemistry, Physics, and Computer Science, University of Southern California, Los Angeles, California 90089, USA
| | - Tamar Golan
- Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Carmit Levy
- Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Remo Rohs
- Molecular and Computational Biology Program, Departments of Biological Sciences, Chemistry, Physics, and Computer Science, University of Southern California, Los Angeles, California 90089, USA
| | - Yael Mandel-Gutfreund
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
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Yang L, Dror I, Zhou T, Mathelier A, Wasserman WW, Gordân R, Rohs R. 15 TFBSshape: a motif database for DNA shape features of transcription factor binding sites. J Biomol Struct Dyn 2015. [DOI: 10.1080/07391102.2015.1032555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Abe N, Dror I, Yang L, Slattery M, Zhou T, Bussemaker HJ, Rohs R, Mann RS. Deconvolving the recognition of DNA shape from sequence. Cell 2015; 161:307-18. [PMID: 25843630 DOI: 10.1016/j.cell.2015.02.008] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/08/2014] [Accepted: 01/26/2015] [Indexed: 01/25/2023]
Abstract
Protein-DNA binding is mediated by the recognition of the chemical signatures of the DNA bases and the 3D shape of the DNA molecule. Because DNA shape is a consequence of sequence, it is difficult to dissociate these modes of recognition. Here, we tease them apart in the context of Hox-DNA binding by mutating residues that, in a co-crystal structure, only recognize DNA shape. Complexes made with these mutants lose the preference to bind sequences with specific DNA shape features. Introducing shape-recognizing residues from one Hox protein to another swapped binding specificities in vitro and gene regulation in vivo. Statistical machine learning revealed that the accuracy of binding specificity predictions improves by adding shape features to a model that only depends on sequence, and feature selection identified shape features important for recognition. Thus, shape readout is a direct and independent component of binding site selection by Hox proteins.
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Affiliation(s)
- Namiko Abe
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - Iris Dror
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA; Department of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Lin Yang
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Matthew Slattery
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA
| | - Tianyin Zhou
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Harmen J Bussemaker
- Department of Biological Sciences, Columbia University, New York, NY 10032, USA
| | - Remo Rohs
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA; Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA; Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA; Department of Computer Science, University of Southern California, Los Angeles, CA 90089, USA.
| | - Richard S Mann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA.
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13
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Yang L, Zhou T, Dror I, Mathelier A, Wasserman WW, Gordân R, Rohs R. TFBSshape: a motif database for DNA shape features of transcription factor binding sites. Nucleic Acids Res 2013; 42:D148-55. [PMID: 24214955 PMCID: PMC3964943 DOI: 10.1093/nar/gkt1087] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Transcription factor binding sites (TFBSs) are most commonly characterized by the nucleotide preferences at each position of the DNA target. Whereas these sequence motifs are quite accurate descriptions of DNA binding specificities of transcription factors (TFs), proteins recognize DNA as a three-dimensional object. DNA structural features refine the description of TF binding specificities and provide mechanistic insights into protein-DNA recognition. Existing motif databases contain extensive nucleotide sequences identified in binding experiments based on their selection by a TF. To utilize DNA shape information when analysing the DNA binding specificities of TFs, we developed a new tool, the TFBSshape database (available at http://rohslab.cmb.usc.edu/TFBSshape/), for calculating DNA structural features from nucleotide sequences provided by motif databases. The TFBSshape database can be used to generate heat maps and quantitative data for DNA structural features (i.e., minor groove width, roll, propeller twist and helix twist) for 739 TF datasets from 23 different species derived from the motif databases JASPAR and UniPROBE. As demonstrated for the basic helix-loop-helix and homeodomain TF families, our TFBSshape database can be used to compare, qualitatively and quantitatively, the DNA binding specificities of closely related TFs and, thus, uncover differential DNA binding specificities that are not apparent from nucleotide sequence alone.
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Affiliation(s)
- Lin Yang
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA, Department of Biology, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada and Institute for Genome Sciences & Policy, Duke University, Durham, NC 27708, USA
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14
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Dror I, Zhou T, Mandel-Gutfreund Y, Rohs R. Covariation between homeodomain transcription factors and the shape of their DNA binding sites. Nucleic Acids Res 2013; 42:430-41. [PMID: 24078250 PMCID: PMC3874178 DOI: 10.1093/nar/gkt862] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Protein–DNA recognition is a critical component of gene regulatory processes but the underlying molecular mechanisms are not yet completely understood. Whereas the DNA binding preferences of transcription factors (TFs) are commonly described using nucleotide sequences, the 3D DNA structure is recognized by proteins and is crucial for achieving binding specificity. However, the ability to analyze DNA shape in a high-throughput manner made it only recently feasible to integrate structural information into studies of protein–DNA binding. Here we focused on the homeodomain family of TFs and analyzed the DNA shape of thousands of their DNA binding sites, investigating the covariation between the protein sequence and the sequence and shape of their DNA targets. We found distinct homeodomain regions that were more correlated with either the nucleotide sequence or the DNA shape of their preferred binding sites, demonstrating different readout mechanisms through which homeodomains attain DNA binding specificity. We identified specific homeodomain residues that likely play key roles in DNA recognition via shape readout. Finally, we showed that adding DNA shape information when characterizing binding sites improved the prediction accuracy of homeodomain binding specificities. Taken together, our findings indicate that DNA shape information can generally provide new mechanistic insights into TF binding.
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Affiliation(s)
- Iris Dror
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA and Department of Biology, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel
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15
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Erlikhman G, Ghose T, Garrigan P, Mnookin J, Dror I, Charleton D, Kellman P. Fingerprint Matching Expertise and its Determinants. J Vis 2013. [DOI: 10.1167/13.9.51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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16
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Zhou T, Yang L, Lu Y, Dror I, Dantas Machado AC, Ghane T, Di Felice R, Rohs R. DNAshape: a method for the high-throughput prediction of DNA structural features on a genomic scale. Nucleic Acids Res 2013; 41:W56-62. [PMID: 23703209 PMCID: PMC3692085 DOI: 10.1093/nar/gkt437] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a method and web server for predicting DNA structural features in a high-throughput (HT) manner for massive sequence data. This approach provides the framework for the integration of DNA sequence and shape analyses in genome-wide studies. The HT methodology uses a sliding-window approach to mine DNA structural information obtained from Monte Carlo simulations. It requires only nucleotide sequence as input and instantly predicts multiple structural features of DNA (minor groove width, roll, propeller twist and helix twist). The results of rigorous validations of the HT predictions based on DNA structures solved by X-ray crystallography and NMR spectroscopy, hydroxyl radical cleavage data, statistical analysis and cross-validation, and molecular dynamics simulations provide strong confidence in this approach. The DNAshape web server is freely available at http://rohslab.cmb.usc.edu/DNAshape/.
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Affiliation(s)
- Tianyin Zhou
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
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17
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Dror I, Zhou T, Mandel-Gutfreund Y, Rohs R. 67 Covariation between homeodomains and the DNA shape of their binding sites provides new insights into protein–DNA recognition. J Biomol Struct Dyn 2013. [DOI: 10.1080/07391102.2013.786501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Gordân R, Shen N, Dror I, Zhou T, Horton J, Rohs R, Bulyk ML. 71 Genomic regions flanking E-box binding sites influence DNA binding specificity of bHLH transcription factors through DNA shape. J Biomol Struct Dyn 2013. [DOI: 10.1080/07391102.2013.786505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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19
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Abe N, Slattery M, Dror I, Rohs R, Honig B, Mann RS. 68 Deconvoluting the recognition of DNA shape from DNA sequence. J Biomol Struct Dyn 2013. [DOI: 10.1080/07391102.2013.786502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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20
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Machado ACD, Saleebyan SB, Holmes BT, Karelina M, Tam J, Kim SY, Kim KH, Dror I, Hodis E, Martz E, Compeau PA, Rohs R. Proteopedia: 3D visualization and annotation of transcription factor-DNA readout modes. Biochem Mol Biol Educ 2012; 40:400-401. [PMID: 23166030 DOI: 10.1002/bmb.20650] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/14/2012] [Indexed: 06/01/2023]
Abstract
3D visualization assists in identifying diverse mechanisms of protein-DNA recognition that can be observed for transcription factors and other DNA binding proteins. We used Proteopedia to illustrate transcription factor-DNA readout modes with a focus on DNA shape, which can be a function of either nucleotide sequence (Hox proteins) or base pairing geometry (p53). © 2012 by The International Union of Biochemistry and Molecular Biology.
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Affiliation(s)
- Ana Carolina Dantas Machado
- Molecular and Computational Biology Program, Departments of Biological Sciences, Chemistry, and Physics and Astronomy, University of Southern California, 1050 Childs Way, Los Angeles, CA 90089, USA
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21
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Slattery M, Riley T, Liu P, Abe N, Gomez-Alcala P, Dror I, Zhou T, Rohs R, Honig B, Bussemaker HJ, Mann RS. Cofactor binding evokes latent differences in DNA binding specificity between Hox proteins. Cell 2012; 147:1270-82. [PMID: 22153072 DOI: 10.1016/j.cell.2011.10.053] [Citation(s) in RCA: 366] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 08/19/2011] [Accepted: 10/06/2011] [Indexed: 11/30/2022]
Abstract
Members of transcription factor families typically have similar DNA binding specificities yet execute unique functions in vivo. Transcription factors often bind DNA as multiprotein complexes, raising the possibility that complex formation might modify their DNA binding specificities. To test this hypothesis, we developed an experimental and computational platform, SELEX-seq, that can be used to determine the relative affinities to any DNA sequence for any transcription factor complex. Applying this method to all eight Drosophila Hox proteins, we show that they obtain novel recognition properties when they bind DNA with the dimeric cofactor Extradenticle-Homothorax (Exd). Exd-Hox specificities group into three main classes that obey Hox gene collinearity rules and DNA structure predictions suggest that anterior and posterior Hox proteins prefer DNA sequences with distinct minor groove topographies. Together, these data suggest that emergent DNA recognition properties revealed by interactions with cofactors contribute to transcription factor specificities in vivo.
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Affiliation(s)
- Matthew Slattery
- Department of Biochemistry and Molecular Biophysics, Columbia University, 701 West 168(th) Street, HHSC 1104, New York, NY 10032, USA
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22
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Dror I, Shazman S, Mukherjee S, Zhang Y, Glaser F, Mandel-Gutfreund Y. Predicting nucleic acid binding interfaces from structural models of proteins. Proteins 2011; 80:482-9. [PMID: 22086767 DOI: 10.1002/prot.23214] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 09/27/2011] [Accepted: 09/30/2011] [Indexed: 11/06/2022]
Abstract
The function of DNA- and RNA-binding proteins can be inferred from the characterization and accurate prediction of their binding interfaces. However, the main pitfall of various structure-based methods for predicting nucleic acid binding function is that they are all limited to a relatively small number of proteins for which high-resolution three-dimensional structures are available. In this study, we developed a pipeline for extracting functional electrostatic patches from surfaces of protein structural models, obtained using the I-TASSER protein structure predictor. The largest positive patches are extracted from the protein surface using the patchfinder algorithm. We show that functional electrostatic patches extracted from an ensemble of structural models highly overlap the patches extracted from high-resolution structures. Furthermore, by testing our pipeline on a set of 55 known nucleic acid binding proteins for which I-TASSER produces high-quality models, we show that the method accurately identifies the nucleic acids binding interface on structural models of proteins. Employing a combined patch approach we show that patches extracted from an ensemble of models better predicts the real nucleic acid binding interfaces compared with patches extracted from independent models. Overall, these results suggest that combining information from a collection of low-resolution structural models could be a valuable approach for functional annotation. We suggest that our method will be further applicable for predicting other functional surfaces of proteins with unknown structure.
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Affiliation(s)
- Iris Dror
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel 32000
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23
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Paz I, Akerman M, Dror I, Kosti I, Mandel-Gutfreund Y. SFmap: a web server for motif analysis and prediction of splicing factor binding sites. Nucleic Acids Res 2010; 38:W281-5. [PMID: 20501600 PMCID: PMC2896136 DOI: 10.1093/nar/gkq444] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Alternative splicing (AS) is a post-transcriptional process considered to be responsible for the huge diversity of proteins in higher eukaryotes. AS events are regulated by different splicing factors (SFs) that bind to sequence elements on the RNA. SFmap is a web server for predicting putative SF binding sites in genomic data (http://sfmap.technion.ac.il). SFmap implements the COS(WR) algorithm, which computes similarity scores for a given regulatory motif based on information derived from its sequence environment and its evolutionary conservation. Input for SFmap is a human genomic sequence or a list of sequences in FASTA format that can either be uploaded from a file or pasted into a window. SFmap searches within a given sequence for significant hits of binding motifs that are either stored in our database or defined by the user. SFmap results are provided both as a text file and as a graphical web interface.
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Affiliation(s)
- Inbal Paz
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
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24
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Krane DE, Bahn V, Balding D, Barlow B, Cash H, Desportes BL, D'Eustachio P, Devlin K, Doom TE, Dror I, Ford S, Funk C, Gilder J, Hampikian G, Inman K, Jamieson A, Kent PE, Koppl R, Kornfield I, Krimsky S, Mnookin J, Mueller L, Murphy E, Paoletti DR, Petrov DA, Raymer M, Risinger DM, Roth A, Rudin N, Shields W, Siegel JA, Slatkin M, Song YS, Speed T, Spiegelman C, Sullivan P, Swienton AR, Tarpey T, Thompson WC, Ungvarsky E, Zabell S. Time for DNA disclosure. Science 2010; 326:1631-2. [PMID: 20019271 DOI: 10.1126/science.326.5960.1631] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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25
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Abstract
This study examined whether stereotypes of aging might contribute to decisions the elderly make about when to die. Old and young participants (N=64) were subliminally primed with either negative or positive stereotypes of old age and then responded to hypothetical medical situations involving potentially fatal illnesses. Consistent with our prediction, the aged participants primed with negative stereotypes tended to refuse life-prolonging interventions, whereas the old participants primed with positive age stereotypes tended to accept the interventions. This priming effect did not emerge among the young participants for whom the stereotypes were less relevant. The results suggest that societally-transmitted negative stereotypes of aging can weaken elderly people's will to live.
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Affiliation(s)
- B Levy
- Department of Epidemiology and Public Health, Yale University, 60 College Street, P.O. Box 208034, New Haven, CT 06520-8034, USA
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26
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Abstract
This study was designed to provide high-density data on spatial distribution of three herbicides with different physiochemical characteristics in a sludge-amended and non-amended control field over the course of an irrigation season. The field experiment was carried out on a sandy loam Hamra Red Mediterranean soil (Rhodoxeralf) at Bet Dagan, Israel. After a single 50 mm irrigation event, the mean centers of mass (COM) in the control field were at 15.6, 14.9, and 17 cm for bromacil, atrazine and terbuthylazine, respectively; in the sludge-amended field, mean COMs were at 28.8, 31.2, and 34.1 cm, respectively. After 500 mm of irrigation in the control field, the COM depth distribution of the three pesticides was inversely correlated with octanol-water (Kow) distribution coefficients and soil sorption coefficients (Koc), and positively correlated with aqueous solubilities. After 500 mm irrigation in the sludge-amended field, the mean terbuthylazine COM was at 19.8 cm versus 13.8 cm for the control field, demonstrating a sustained enhanced effect on terbuthylazine transport. Downward transport of atrazine was also enhanced by sludge amendment, albeit less than terbuthylazine. Bromacil was preferentially accumulated in the upper soil layers of the sludge-amended field as compared with the control field after 500 mm irrigation. The enhanced transport of all three pesticides in the sludge-amended field after a single irrigation event is attributed to development of preferential flow pathways around hydrophobic clods of sludge. Enhanced transport of terbuthylazine, and to a lesser extent, atrazine, throughout the irrigation season, is attributed to their transport as complexes with dissolved, colloidal and suspended organic matter derived from sludge degradation.
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Affiliation(s)
- E R Graber
- Institute of Soil, Water and Environmental Sciences, The Volcani Center, Agricultural Research Organization, Bet Dagan, Israel.
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27
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Abstract
A field experiment was designed to determine the combined effect of leaching and natural attenuation on the redistribution dynamics of kerosene--a volatile petroleum hydrocarbon mixture (VPHM)--and of its selected individual components in the soil subsurface. Variables included the composition of contaminant spilled, the soil water content before contamination and the leaching pattern. Temporal changes in the residual kerosene concentration and composition in the soil subsurface of the experimental field during 39 days and leaching by 500 mm of irrigation water were determined to a depth of 100 cm. The main processes controlling contaminant attenuation were volatilization and redistribution with depth. Soil hydration status was found to affect the attenuation, redistribution and composition of VPHM in the porous media. An initial relative increase of n-alkanes in the subsurface compared with the total VPHM in the first leaching period was a result of the volatilization of low vapor pressure compounds. The redistribution of individual components in the soil profile during leaching was in accordance with their physico-chemical properties.
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Affiliation(s)
- I Dror
- Institute of Soil, Water and Environmental Sciences, ARO, The Volcani Center, Bet Dagan 50250, Israel.
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28
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Dror I, Sandrov A, Kopeika NS. Experimental investigation of the influence of the relative position of the scattering layer on image quality: the shower curtain effect. Appl Opt 1998; 37:6495-6499. [PMID: 18286158 DOI: 10.1364/ao.37.006495] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The imaging quality of optical systems in a turbid environment is influenced not only by the content of the turbid layer between the object and the optical receiver but also by the inhomogeneity of that medium. This is important, particularly when imaging is performed through clouds, nonhomogeneous layers of dust, or over vertical or slant paths through the atmosphere. Forward small-angle scattering influences image quality and blur more severely when the scattering layer is closer to the receiver. In this study it is the influence of the relative position of the scattering layer on the image quality and modulation transfer function (MTF) that is investigated. The scattering layer in controlled laboratory experiments consists of calibrated polystyrene particles of known size and quantity in a small cuvette. A point source was imaged by a computerized imaging system through a layer containing polystyrene particles, and the point-spread function (PSF) was recorded. The aerosol MTF was calculated using the measured PSF. The MTF was measured as a function of changing relative distance of the scattering layer from the receiver, whereas the object-plane-to-receiver distance was constant. The experimental results were compared to theoretical shower curtain effect models based on the solution from radiative transfer theory under the small-angle approximation. Although the general trend of the experimental results certainly agrees with the theoretical models, it could be that the small-angle approximation method might be of limited validity at such low spatial frequencies. Aggregation also causes some disagreement with predictions from theory.
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29
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Dror I, Kopeika NS. Aerosol and turbulence modulation transfer functions: comparison measurements in the open atmosphere. Opt Lett 1992; 17:1532. [PMID: 19798238 DOI: 10.1364/ol.17.001532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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30
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Sandbank U, Bubis JJ, Bartov I, Dror I, Budowski P, Wolman M. Basal membrane labyrinths in the healing stages of chick nutritional encephalopathy. Neuropathol Appl Neurobiol 1980; 6:3-8. [PMID: 7374910 DOI: 10.1111/j.1365-2990.1980.tb00198.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Chicks were fed a diet rich in oxidized oil and deficient in alpha-tocopherol. As soon as nutritional encephalopathy developed the animals were immediately put on to a normal diet, and kept alive for up to 166 days. Examination of the cerebellum showed multiple foci of healed encephalomalacia with EM appearance of basal membrane labyrinths between astroglial cells and around blood vessels. The possible origin of the basement membrane material in this conditions was considered and compared with similar formations in normal animals, in CNS tumour explants, and after portocaval anastomosis as well as after spinal cord lesions.
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