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Cho HJ, Gurbuz F, Stamou M, Kotan LD, Farmer SM, Can S, Tompkins MF, Mammadova J, Altincik SA, Gokce C, Catli G, Bugrul F, Bartlett K, Turan I, Balasubramanian R, Yuksel B, Seminara SB, Wray S, Topaloglu AK. POU6F2 mutation in humans with pubertal failure alters GnRH transcript expression. Front Endocrinol (Lausanne) 2023; 14:1203542. [PMID: 37600690 PMCID: PMC10436210 DOI: 10.3389/fendo.2023.1203542] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/23/2023] [Indexed: 08/22/2023] Open
Abstract
Idiopathic hypogonadotropic hypogonadism (IHH) is characterized by the absence of pubertal development and subsequent impaired fertility often due to gonadotropin-releasing hormone (GnRH) deficits. Exome sequencing of two independent cohorts of IHH patients identified 12 rare missense variants in POU6F2 in 15 patients. POU6F2 encodes two distinct isoforms. In the adult mouse, expression of both isoform1 and isoform2 was detected in the brain, pituitary, and gonads. However, only isoform1 was detected in mouse primary GnRH cells and three immortalized GnRH cell lines, two mouse and one human. To date, the function of isoform2 has been verified as a transcription factor, while the function of isoform1 has been unknown. In the present report, bioinformatics and cell assays on a human-derived GnRH cell line reveal a novel function for isoform1, demonstrating it can act as a transcriptional regulator, decreasing GNRH1 expression. In addition, the impact of the two most prevalent POU6F2 variants, identified in five IHH patients, that were located at/or close to the DNA-binding domain was examined. Notably, one of these mutations prevented the repression of GnRH transcripts by isoform1. Normally, GnRH transcription increases as GnRH cells mature as they near migrate into the brain. Augmentation earlier during development can disrupt normal GnRH cell migration, consistent with some POU6F2 variants contributing to the IHH pathogenesis.
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Affiliation(s)
- Hyun-Ju Cho
- Cellular and Developmental Neurobiology Section, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Fatih Gurbuz
- Division of Pediatric Endocrinology, Faculty of Medicine, Cukurova University, Adana, Türkiye
| | - Maria Stamou
- Harvard Reproductive Sciences Center, The Reproductive Endocrine Unit and The Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, MA, United States
| | - Leman Damla Kotan
- Division of Pediatric Endocrinology, Faculty of Medicine, Cukurova University, Adana, Türkiye
| | - Stephen Matthew Farmer
- Cellular and Developmental Neurobiology Section, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Sule Can
- Division of Pediatric Endocrinology, İzmir Tepecik Training and Research Hospital, Health Sciences University, İzmir, Türkiye
| | - Miranda Faith Tompkins
- Cellular and Developmental Neurobiology Section, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Jamala Mammadova
- Division of Pediatric Endocrinology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Türkiye
| | - S. Ayca Altincik
- Division of Pediatric Endocrinology, Faculty of Medicine, Pamukkale University, Denizli, Türkiye
| | - Cumali Gokce
- Division of Endocrinology, Faculty of Medicine, Mustafa Kemal University, Hatay, Türkiye
| | - Gonul Catli
- Division of Pediatric Endocrinology, İzmir Tepecik Training and Research Hospital, Health Sciences University, İzmir, Türkiye
| | - Fuat Bugrul
- Division of Pediatric Endocrinology, Faculty of Medicine, Selcuk University, Konya, Türkiye
| | - Keenan Bartlett
- Cellular and Developmental Neurobiology Section, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Ihsan Turan
- Division of Pediatric Endocrinology, Faculty of Medicine, Cukurova University, Adana, Türkiye
| | - Ravikumar Balasubramanian
- Harvard Reproductive Sciences Center, The Reproductive Endocrine Unit and The Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, MA, United States
| | - Bilgin Yuksel
- Division of Pediatric Endocrinology, Faculty of Medicine, Cukurova University, Adana, Türkiye
| | - Stephanie B. Seminara
- Harvard Reproductive Sciences Center, The Reproductive Endocrine Unit and The Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, MA, United States
| | - Susan Wray
- Cellular and Developmental Neurobiology Section, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - A. Kemal Topaloglu
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Mississippi Medical Center, Jackson, MS, United States
- Division of Pediatric Endocrinology, Massachusetts General Hospital for Children and Harvard Medical School, Boston, MS, United States
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Prolič-Kalinšek M, Volkov AN, Hadži S, Van Dyck J, Bervoets I, Charlier D, Loris R. Structural basis of DNA binding by YdaT, a functional equivalent of the CII repressor in the cryptic prophage CP-933P from Escherichia coli O157:H7. Acta Crystallogr D Struct Biol 2023; 79:245-258. [PMID: 36876434 PMCID: PMC9986795 DOI: 10.1107/s2059798323001249] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 02/10/2023] [Indexed: 03/01/2023] Open
Abstract
YdaT is a functional equivalent of the CII repressor in certain lambdoid phages and prophages. YdaT from the cryptic prophage CP-933P in the genome of Escherichia coli O157:H7 is functional as a DNA-binding protein and recognizes a 5'-TTGATTN6AATCAA-3' inverted repeat. The DNA-binding domain is a helix-turn-helix (HTH)-containing POU domain and is followed by a long α-helix (α6) that forms an antiparallel four-helix bundle, creating a tetramer. The loop between helix α2 and the recognition helix α3 in the HTH motif is unusually long compared with typical HTH motifs, and is highly variable in sequence and length within the YdaT family. The POU domains have a large degree of freedom to move relative to the helix bundle in the free structure, but their orientation becomes fixed upon DNA binding.
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Affiliation(s)
- Maruša Prolič-Kalinšek
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium
| | - Alexander N Volkov
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium
| | - San Hadži
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Jeroen Van Dyck
- Department of Chemistry, Universiteit Antwerpen, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Indra Bervoets
- Research Group of Microbiology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium
| | - Daniel Charlier
- Research Group of Microbiology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium
| | - Remy Loris
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium
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Bhargava A. Unraveling corticotropin-releasing factor family-orchestrated signaling and function in both sexes. VITAMINS AND HORMONES 2023; 123:27-65. [PMID: 37717988 DOI: 10.1016/bs.vh.2023.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Stress responses to physical, psychological, environmental, or cellular stressors, has two arms: initiation and recovery. Corticotropin-releasing factor (CRF) is primarily responsible for regulating and/or initiating stress responses via, whereas urocortins (UCNs) are involved in the recovery response to stress via feedback inhibition. Stress is a loaded, polysemous word and is experienced in a myriad of ways. Some stressors are good for an individual, in fact essential, whereas other stressors are associated with bad outcomes. Perceived stress, like beauty, lies in the eye of the beholder, and hence the same stressor can result in individual-specific outcomes. In mammals, there are two main biological sexes with reproduction as primary function. Reproduction and nutrition can also be viewed as stressors; based on a body of work from my laboratory, we propose that the functions of all other organs have co-evolved to optimize and facilitate an individual's nutritional and reproductive functions. Hence, sex differences in physiologically relevant outcomes are innate and occur at all levels- molecular, endocrine, immune, and (patho)physiological. CRF and three UCNs are peptide hormones that mediate their physiological effects by binding to two known G protein-coupled receptors (GPCRs), CRF1 and CRF2. Expression and function of CRF family of hormones and their receptors is likely to be sexually dimorphic in all organs. In this chapter, based on the large body of work from others and my laboratory, an overview of the CRF family with special emphasis on sex-specific actions of peripherally expressed CRF2 receptor in health and disease is provided.
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Affiliation(s)
- Aditi Bhargava
- Center for Reproductive Sciences, Department of Obstetrics and Gynecology, University of California San Francisco, San Francisco, CA, United States.
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Käppel S, Eggeling R, Rümpler F, Groth M, Melzer R, Theißen G. DNA-binding properties of the MADS-domain transcription factor SEPALLATA3 and mutant variants characterized by SELEX-seq. PLANT MOLECULAR BIOLOGY 2021; 105:543-557. [PMID: 33486697 PMCID: PMC7892521 DOI: 10.1007/s11103-020-01108-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 12/11/2020] [Indexed: 05/13/2023]
Abstract
We studied the DNA-binding profile of the MADS-domain transcription factor SEPALLATA3 and mutant variants by SELEX-seq. DNA-binding characteristics of SEPALLATA3 mutant proteins lead us to propose a novel DNA-binding mode. MIKC-type MADS-domain proteins, which function as essential transcription factors in plant development, bind as dimers to a 10-base-pair AT-rich motif termed CArG-box. However, this consensus motif cannot fully explain how the abundant family members in flowering plants can bind different target genes in specific ways. The aim of this study was to better understand the DNA-binding specificity of MADS-domain transcription factors. Also, we wanted to understand the role of a highly conserved arginine residue for binding specificity of the MADS-domain transcription factor family. Here, we studied the DNA-binding profile of the floral homeotic MADS-domain protein SEPALLATA3 by performing SELEX followed by high-throughput sequencing (SELEX-seq). We found a diverse set of bound sequences and could estimate the in vitro binding affinities of SEPALLATA3 to a huge number of different sequences. We found evidence for the preference of AT-rich motifs as flanking sequences. Whereas different CArG-boxes can act as SEPALLATA3 binding sites, our findings suggest that the preferred flanking motifs are almost always the same and thus mostly independent of the identity of the central CArG-box motif. Analysis of SEPALLATA3 proteins with a single amino acid substitution at position 3 of the DNA-binding MADS-domain further revealed that the conserved arginine residue, which has been shown to be involved in a shape readout mechanism, is especially important for the recognition of nucleotides at positions 3 and 8 of the CArG-box motif. This leads us to propose a novel DNA-binding mode for SEPALLATA3, which is different from that of other MADS-domain proteins known.
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Affiliation(s)
- Sandra Käppel
- Matthias Schleiden Institute/Genetics, Friedrich Schiller University Jena, Philosophenweg 12, 07743, Jena, Germany
| | - Ralf Eggeling
- Department of Computer Science, University of Helsinki, Pietari Kalmin katu 5, 00014, Helsinki, Finland
- Methods in Medical Informatics, Department of Computer Science, University of Tübingen, Sand 14, 72076, Tübingen, Germany
- Institute for Biomedical Informatics, University of Tübingen, Tübingen, Germany
| | - Florian Rümpler
- Matthias Schleiden Institute/Genetics, Friedrich Schiller University Jena, Philosophenweg 12, 07743, Jena, Germany
| | - Marco Groth
- Leibniz Institute on Aging-Fritz Lipmann Institute (FLI), Core Facility DNA Sequencing, Beutenbergstraße 11, 07745, Jena, Germany
| | - Rainer Melzer
- School of Biology and Environmental Science and Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Günter Theißen
- Matthias Schleiden Institute/Genetics, Friedrich Schiller University Jena, Philosophenweg 12, 07743, Jena, Germany.
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POU domain motif3 (Pdm3) induces wingless (wg) transcription and is essential for development of larval neuromuscular junctions in Drosophila. Sci Rep 2020; 10:517. [PMID: 31949274 PMCID: PMC6965103 DOI: 10.1038/s41598-020-57425-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/31/2019] [Indexed: 02/07/2023] Open
Abstract
Wnt is a conserved family of secreted proteins that play diverse roles in tissue growth and differentiation. Identification of transcription factors that regulate wnt expression is pivotal for understanding tissue-specific signaling pathways regulated by Wnt. We identified pdm3m7, a new allele of the pdm3 gene encoding a POU family transcription factor, in a lethality-based genetic screen for modifiers of Wingless (Wg) signaling in Drosophila. Interestingly, pdm3m7 larvae showed slow locomotion, implying neuromuscular defects. Analysis of larval neuromuscular junctions (NMJs) revealed decreased bouton number with enlarged bouton in pdm3 mutants. pdm3 NMJs also had fewer branches at axon terminals than wild-type NMJs. Consistent with pdm3m7 being a candidate wg modifier, NMJ phenotypes in pdm3 mutants were similar to those of wg mutants, implying a functional link between these two genes. Indeed, lethality caused by Pdm3 overexpression in motor neurons was completely rescued by knockdown of wg, indicating that Pdm3 acts upstream to Wg. Furthermore, transient expression of Pdm3 induced ectopic expression of wg-LacZ reporter and Wg effector proteins in wing discs. We propose that Pdm3 expressed in presynaptic NMJ neurons regulates wg transcription for growth and development of both presynaptic neurons and postsynaptic muscles.
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Karthigeyan D, Bose A, Boopathi R, Rao VJ, Shima H, Bharathy N, Igarashi K, Taneja R, Trivedi AK, Kundu TK. Aurora kinase A-mediated phosphorylation of mPOU at a specific site drives skeletal muscle differentiation. J Biochem 2019; 167:195-201. [DOI: 10.1093/jb/mvz088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 09/15/2019] [Indexed: 12/17/2022] Open
Abstract
Abstract
Aurora kinases are Ser/Thr-directed protein kinases which play pivotal roles in mitosis. Recent evidences highlight the importance of these kinases in multiple biological events including skeletal muscle differentiation. Our earlier study identified the transcription factor POU6F1 (or mPOU) as a novel Aurora kinase (Aurk) A substrate. Here, we report that Aurora kinase A phosphorylates mPOU at Ser197 and inhibit its DNA-binding ability. Delving into mPOU physiology, we find that the phospho-mimic (S197D) mPOU mutant exhibits enhancement, while the wild type or the phospho-deficient mutant shows retardation in C2C12 myoblast differentiation. Interestingly, POU6F1 depletion phenocopies S197D-mPOU overexpression in the differentiation context. Collectively, our results signify mPOU as a negative regulator of skeletal muscle differentiation and strengthen the importance of AurkA in skeletal myogenesis.
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Affiliation(s)
- Dhanasekan Karthigeyan
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
| | - Arnab Bose
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
| | - Ramachandran Boopathi
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
| | - Vinay Jaya Rao
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
| | - Hiroki Shima
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Aoba-ku, Sendai 980-8575, Japan
| | - Narendra Bharathy
- Department of Physiology, Cellular Differentiation and Apoptosis, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Kazuhiko Igarashi
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Aoba-ku, Sendai 980-8575, Japan
| | - Reshma Taneja
- Department of Physiology, Cellular Differentiation and Apoptosis, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Arun Kumar Trivedi
- Division of Cancer Biology, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector-10, Jankipuram Extension, Lucknow 226031, Uttar Pradesh, India
| | - Tapas K Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
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Malik V, Zimmer D, Jauch R. Diversity among POU transcription factors in chromatin recognition and cell fate reprogramming. Cell Mol Life Sci 2018; 75:1587-1612. [PMID: 29335749 PMCID: PMC11105716 DOI: 10.1007/s00018-018-2748-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/23/2017] [Accepted: 01/08/2018] [Indexed: 12/28/2022]
Abstract
The POU (Pit-Oct-Unc) protein family is an evolutionary ancient group of transcription factors (TFs) that bind specific DNA sequences to direct gene expression programs. The fundamental importance of POU TFs to orchestrate embryonic development and to direct cellular fate decisions is well established, but the molecular basis for this activity is insufficiently understood. POU TFs possess a bipartite 'two-in-one' DNA binding domain consisting of two independently folding structural units connected by a poorly conserved and flexible linker. Therefore, they represent a paradigmatic example to study the molecular basis for the functional versatility of TFs. Their modular architecture endows POU TFs with the capacity to accommodate alternative composite DNA sequences by adopting different quaternary structures. Moreover, associations with partner proteins crucially influence the selection of their DNA binding sites. The plentitude of DNA binding modes confers the ability to POU TFs to regulate distinct genes in the context of different cellular environments. Likewise, different binding modes of POU proteins to DNA could trigger alternative regulatory responses in the context of different genomic locations of the same cell. Prominent POU TFs such as Oct4, Brn2, Oct6 and Brn4 are not only essential regulators of development but have also been successfully employed to reprogram somatic cells to pluripotency and neural lineages. Here we review biochemical, structural, genomic and cellular reprogramming studies to examine how the ability of POU TFs to select regulatory DNA, alone or with partner factors, is tied to their capacity to epigenetically remodel chromatin and drive specific regulatory programs that give cells their identities.
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Affiliation(s)
- Vikas Malik
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 511436, China
- Genome Regulation Laboratory, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Dennis Zimmer
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 511436, China
- Genome Regulation Laboratory, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Ralf Jauch
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 511436, China.
- Genome Regulation Laboratory, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.
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The ATM- and ATR-related SCD domain is over-represented in proteins involved in nervous system development. Sci Rep 2016; 6:19050. [PMID: 26743489 PMCID: PMC4705472 DOI: 10.1038/srep19050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/02/2015] [Indexed: 12/16/2022] Open
Abstract
ATM and ATR are cellular kinases with a well-characterized role in the DNA-damage response. Although the complete set of ATM/ATR targets is unknown, they often contain clusters of S/TQ motifs that constitute an SCD domain. In this study, we identified putative ATM/ATR targets that have a conserved SCD domain across vertebrates. Using this approach, we have identified novel putative ATM/ATR targets in pathways known to be under direct control of these kinases. Our analysis has also unveiled significant enrichment of SCD-containing proteins in cellular pathways, such as vesicle trafficking and actin cytoskeleton, where a regulating role for ATM/ATR is either unknown or poorly understood, hinting at a much broader and overarching role for these kinases in the cell. Of particular note is the overrepresentation of conserved SCD-containing proteins involved in pathways related to neural development. This finding suggests that ATM/ATR could be directly involved in controlling this process, which may be linked to the adverse neurological effects observed in patients with mutations in ATM.
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Jerabek S, Merino F, Schöler HR, Cojocaru V. OCT4: dynamic DNA binding pioneers stem cell pluripotency. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1839:138-54. [PMID: 24145198 DOI: 10.1016/j.bbagrm.2013.10.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 10/02/2013] [Accepted: 10/06/2013] [Indexed: 12/12/2022]
Abstract
OCT4 was discovered more than two decades ago as a transcription factor specific to early embryonic development. Early studies with OCT4 were descriptive and looked at determining the functional roles of OCT4 in the embryo as well as in pluripotent cell lines derived from embryos. Later studies showed that OCT4 was one of the transcription factors in the four-factor cocktail required for reprogramming somatic cells into induced pluripotent stem cells (iPSCs) and that it is the only factor that cannot be substituted in this process by other members of the same protein family. In recent years, OCT4 has emerged as a master regulator of the induction and maintenance of cellular pluripotency, with crucial roles in the early stages of differentiation. Currently, mechanistic studies look at elucidating the molecular details of how OCT4 contributes to establishing selective gene expression programs that define different developmental stages of pluripotent cells. OCT4 belongs to the POU family of proteins, which have two conserved DNA-binding domains connected by a variable linker region. The functions of OCT4 depend on its ability to recognize and bind to DNA regulatory regions alone or in cooperation with other transcription factors and on its capacity to recruit other factors required to regulate the expression of specific sets of genes. Undoubtedly, future iPSC-based applications in regenerative medicine will benefit from understanding how OCT4 functions. Here we provide an integrated view of OCT4 research conducted to date by reviewing the different functional roles for OCT4 and discussing the current progress in understanding their underlying molecular mechanisms. This article is part of a Special Issue entitled: Chromatin and epigenetic regulation of animal development.
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Affiliation(s)
- Stepan Jerabek
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Felipe Merino
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Hans Robert Schöler
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany.
| | - Vlad Cojocaru
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany.
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Functional specificity of a protein-DNA complex mediated by two arginines bound to the minor groove. J Bacteriol 2012; 194:4727-35. [PMID: 22753063 DOI: 10.1128/jb.00677-12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A bacteriophage Ø29 transcriptional regulator, protein p4, interacts with its DNA target by employing two mechanisms: by direct readout of the chemical signatures of only one DNA base and by inducing local modification on the topology of short A tracts (indirect readout). p4 binds as a dimer to targets consisting of imperfect inverted repeats. Here we used molecular dynamic simulation to define interactions of a cluster of 12 positively charged amino acids of p4 with DNA and biochemical assays with modified DNA targets and mutated proteins to quantify the contribution of residues in the nucleoprotein complex. Our results show the implication of Arg54, with non-base-specific interaction in the central A tract, in p4 binding affinity. Despite being chemically equivalent and in identical protein monomers, the two Arg54 residues differed in their interactions with DNA. We discuss an indirect-readout mechanism for p4-DNA recognition mediated by dissimilar interaction of arginines penetrating the minor groove and the inherent properties of the A tract. Our findings extend the current understanding of protein-DNA recognition and contribute to the relevance of the sequence-dependent conformational malleability of the DNA, shedding light on the role of arginines in binding affinity. Characterization of mutant p4R54A shows that the residue is required for the activity of the protein as a transcriptional regulator.
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Rohs R, Jin X, West SM, Joshi R, Honig B, Mann RS. Origins of specificity in protein-DNA recognition. Annu Rev Biochem 2010; 79:233-69. [PMID: 20334529 DOI: 10.1146/annurev-biochem-060408-091030] [Citation(s) in RCA: 656] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Specific interactions between proteins and DNA are fundamental to many biological processes. In this review, we provide a revised view of protein-DNA interactions that emphasizes the importance of the three-dimensional structures of both macromolecules. We divide protein-DNA interactions into two categories: those when the protein recognizes the unique chemical signatures of the DNA bases (base readout) and those when the protein recognizes a sequence-dependent DNA shape (shape readout). We further divide base readout into those interactions that occur in the major groove from those that occur in the minor groove. Analogously, the readout of the DNA shape is subdivided into global shape recognition (for example, when the DNA helix exhibits an overall bend) and local shape recognition (for example, when a base pair step is kinked or a region of the minor groove is narrow). Based on the >1500 structures of protein-DNA complexes now available in the Protein Data Bank, we argue that individual DNA-binding proteins combine multiple readout mechanisms to achieve DNA-binding specificity. Specificity that distinguishes between families frequently involves base readout in the major groove, whereas shape readout is often exploited for higher resolution specificity, to distinguish between members within the same DNA-binding protein family.
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Affiliation(s)
- Remo Rohs
- Howard Hughes Medical Institute, Center for Computational Biology and Bioinformatics, Columbia University, New York, NY 10032, USA
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