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Starkova T, Polyanichko A, Tomilin AN, Chikhirzhina E. Structure and Functions of HMGB2 Protein. Int J Mol Sci 2023; 24:ijms24098334. [PMID: 37176041 PMCID: PMC10179549 DOI: 10.3390/ijms24098334] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
High-Mobility Group (HMG) chromosomal proteins are the most numerous nuclear non-histone proteins. HMGB domain proteins are the most abundant and well-studied HMG proteins. They are involved in variety of biological processes. HMGB1 and HMGB2 were the first members of HMGB-family to be discovered and are found in all studied eukaryotes. Despite the high degree of homology, HMGB1 and HMGB2 proteins differ from each other both in structure and functions. In contrast to HMGB2, there is a large pool of works devoted to the HMGB1 protein whose structure-function properties have been described in detail in our previous review in 2020. In this review, we attempted to bring together diverse data about the structure and functions of the HMGB2 protein. The review also describes post-translational modifications of the HMGB2 protein and its role in the development of a number of diseases. Particular attention is paid to its interaction with various targets, including DNA and protein partners. The influence of the level of HMGB2 expression on various processes associated with cell differentiation and aging and its ability to mediate the differentiation of embryonic and adult stem cells are also discussed.
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Affiliation(s)
- Tatiana Starkova
- Laboratory of Molecular Biology of Stem Cells, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Av. 4, 194064 St. Petersburg, Russia
| | - Alexander Polyanichko
- Laboratory of Molecular Biology of Stem Cells, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Av. 4, 194064 St. Petersburg, Russia
| | - Alexey N Tomilin
- Laboratory of Molecular Biology of Stem Cells, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Av. 4, 194064 St. Petersburg, Russia
| | - Elena Chikhirzhina
- Laboratory of Molecular Biology of Stem Cells, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Av. 4, 194064 St. Petersburg, Russia
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2
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Epimutations and Their Effect on Chromatin Organization: Exciting Avenues for Cancer Treatment. Cancers (Basel) 2022; 15:cancers15010215. [PMID: 36612210 PMCID: PMC9818548 DOI: 10.3390/cancers15010215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/14/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022] Open
Abstract
The three-dimensional architecture of genomes is complex. It is organized as fibers, loops, and domains that form high-order structures. By using different chromosome conformation techniques, the complex relationship between transcription and genome organization in the three-dimensional organization of genomes has been deciphered. Epigenetic changes, such as DNA methylation and histone modification, are the hallmark of cancers. Tumor initiation, progression, and metastasis are linked to these epigenetic modifications. Epigenetic inhibitors can reverse these altered modifications. A number of epigenetic inhibitors have been approved by FDA that target DNA methylation and histone modification. This review discusses the techniques involved in studying the three-dimensional organization of genomes, DNA methylation and histone modification, epigenetic deregulation in cancer, and epigenetic therapies targeting the tumor.
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Tsujikawa LM, Kharenko OA, Stotz SC, Rakai BD, Sarsons CD, Gilham D, Wasiak S, Fu L, Sweeney M, Johansson JO, Wong NCW, Kulikowski E. Breaking boundaries: Pan BETi disrupt 3D chromatin structure, BD2-selective BETi are strictly epigenetic transcriptional regulators. Biomed Pharmacother 2022; 152:113230. [PMID: 35687908 DOI: 10.1016/j.biopha.2022.113230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/25/2022] [Accepted: 06/01/2022] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Bromodomain and extraterminal proteins (BETs) are more than just epigenetic regulators of transcription. Here we highlight a new role for the BET protein BRD4 in the maintenance of higher order chromatin structure at Topologically Associating Domain Boundaries (TADBs). BD2-selective and pan (non-selective) BET inhibitors (BETi) differentially support chromatin structure, selectively affecting transcription and cell viability. METHODS Using RNA-seq and BRD4 ChIP-seq, the differential effect of BETi treatment on the transcriptome and BRD4 chromatin occupancy of human aortic endothelial cells from diabetic patients (dHAECs) stimulated with TNFα was evaluated. Chromatin decondensation and DNA fragmentation was assessed by immunofluorescence imaging and quantification. Key dHAEC findings were verified in proliferating monocyte-like THP-1 cells using real time-PCR, BRD4 co-immunoprecipitation studies, western blots, proliferation and apoptosis assays. FINDINGS We discovered that 1) BRD4 co-localizes with Ying-Yang 1 (YY1) at TADBs, critical chromatin structure complexes proximal to many DNA repair genes. 2) BD2-selective BETi enrich BRD4/YY1 associations, while pan-BETi do not. 3) Failure to support chromatin structures through BRD4/YY1 enrichment inhibits DNA repair gene transcription, which induces DNA damage responses, and causes widespread chromatin decondensation, DNA fragmentation, and apoptosis. 4) BD2-selective BETi maintain high order chromatin structure and cell viability, while reducing deleterious pro-inflammatory transcription. INTERPRETATION BRD4 plays a previously unrecognized role at TADBs. BETi differentially impact TADB stability. Our results provide translational insight for the development of BETi as therapeutics for a range of diseases including CVD, chronic kidney disease, cancer, and COVID-19.
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Affiliation(s)
- Laura M Tsujikawa
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
| | - Olesya A Kharenko
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
| | - Stephanie C Stotz
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
| | - Brooke D Rakai
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
| | - Christopher D Sarsons
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
| | - Dean Gilham
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
| | - Sylwia Wasiak
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
| | - Li Fu
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
| | - Michael Sweeney
- Resverlogix Corporation, Suite 4010, 44 Montgomery Street, San Francisco, CA 94104, USA.
| | - Jan O Johansson
- Resverlogix Corporation, Suite 4010, 44 Montgomery Street, San Francisco, CA 94104, USA.
| | - Norman C W Wong
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
| | - Ewelina Kulikowski
- Resverlogix Corporation, Suite 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada.
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Hu G, Dong X, Gong S, Song Y, Hutchins AP, Yao H. Systematic screening of CTCF binding partners identifies that BHLHE40 regulates CTCF genome-wide distribution and long-range chromatin interactions. Nucleic Acids Res 2020; 48:9606-9620. [PMID: 32885250 PMCID: PMC7515718 DOI: 10.1093/nar/gkaa705] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 07/27/2020] [Accepted: 08/14/2020] [Indexed: 11/14/2022] Open
Abstract
CTCF plays a pivotal role in mediating chromatin interactions, but it does not do so alone. A number of factors have been reported to co-localize with CTCF and regulate CTCF loops, but no comprehensive analysis of binding partners has been performed. This prompted us to identify CTCF loop participants and regulators by co-localization analysis with CTCF. We screened all factors that had ChIP-seq data in humans by co-localization analysis with human super conserved CTCF (hscCTCF) binding sites, and identified many new factors that overlapped with hscCTCF binding sites. Combined with CTCF loop information, we observed that clustered factors could promote CTCF loops. After in-depth mining of each factor, we found that many factors might have the potential to promote CTCF loops. Our data further demonstrated that BHLHE40 affected CTCF loops by regulating CTCF binding. Together, this study revealed that many factors have the potential to participate in or regulate CTCF loops, and discovered a new role for BHLHE40 in modulating CTCF loop formation.
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Affiliation(s)
- Gongcheng Hu
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health GuangDong Laboratory), Guangzhou 510005, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaotao Dong
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health GuangDong Laboratory), Guangzhou 510005, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shixin Gong
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health GuangDong Laboratory), Guangzhou 510005, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yawei Song
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health GuangDong Laboratory), Guangzhou 510005, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Andrew P Hutchins
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
| | - Hongjie Yao
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health GuangDong Laboratory), Guangzhou 510005, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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5
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Kane AE, Sinclair DA. Epigenetic changes during aging and their reprogramming potential. Crit Rev Biochem Mol Biol 2019; 54:61-83. [PMID: 30822165 PMCID: PMC6424622 DOI: 10.1080/10409238.2019.1570075] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 01/09/2019] [Accepted: 01/11/2019] [Indexed: 02/07/2023]
Abstract
The aging process results in significant epigenetic changes at all levels of chromatin and DNA organization. These include reduced global heterochromatin, nucleosome remodeling and loss, changes in histone marks, global DNA hypomethylation with CpG island hypermethylation, and the relocalization of chromatin modifying factors. Exactly how and why these changes occur is not fully understood, but evidence that these epigenetic changes affect longevity and may cause aging, is growing. Excitingly, new studies show that age-related epigenetic changes can be reversed with interventions such as cyclic expression of the Yamanaka reprogramming factors. This review presents a summary of epigenetic changes that occur in aging, highlights studies indicating that epigenetic changes may contribute to the aging process and outlines the current state of research into interventions to reprogram age-related epigenetic changes.
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Affiliation(s)
- Alice E. Kane
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Charles Perkins Centre, The University of Sydney, Sydney, Australia
| | - David A. Sinclair
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Pharmacology, The University of New South Wales, Sydney, Australia
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6
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Spermiogenesis and Male Fertility Require the Function of Suppressor of Hairy-Wing in Somatic Cyst Cells of Drosophila. Genetics 2018; 209:757-772. [PMID: 29739818 DOI: 10.1534/genetics.118.301088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/01/2018] [Indexed: 02/07/2023] Open
Abstract
Drosophila Suppressor of Hairy-wing [Su(Hw)] protein is an example of a multivalent transcription factor. Although best known for its role in establishing the chromatin insulator of the gypsy retrotransposon, Su(Hw) functions as an activator and repressor at non-gypsy genomic sites. It remains unclear how the different regulatory activities of Su(Hw) are utilized during development. Motivated from observations of spatially restricted expression of Su(Hw) in the testis, we investigated the role of Su(Hw) in spermatogenesis to advance an understanding of its developmental contributions as an insulator, repressor, and activator protein. We discovered that Su(Hw) is required for sustained male fertility. Although dynamics of Su(Hw) expression coincide with changes in nuclear architecture and activation of coregulated testis-specific gene clusters, we show that loss of Su(Hw) does not disrupt meiotic chromosome pairing or transcription of testis-specific genes, suggesting that Su(Hw) has minor architectural or insulator functions in the testis. Instead, Su(Hw) has a prominent role as a repressor of neuronal genes, consistent with suggestions that Su(Hw) is a functional homolog of mammalian REST, a repressor of neuronal genes in non-neuronal tissues. We show that Su(Hw) regulates transcription in both germline and somatic cells. Surprisingly, the essential spermatogenesis function of Su(Hw) resides in somatic cyst cells, implying context-specific consequences due to loss of this transcription factor. Together, our studies highlight that Su(Hw) has a major developmental function as a transcriptional repressor, with the effect of its loss dependent upon the cell-specific factors.
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Baxley RM, Bullard JD, Klein MW, Fell AG, Morales-Rosado JA, Duan T, Geyer PK. Deciphering the DNA code for the function of the Drosophila polydactyl zinc finger protein Suppressor of Hairy-wing. Nucleic Acids Res 2017; 45:4463-4478. [PMID: 28158673 PMCID: PMC5416891 DOI: 10.1093/nar/gkx040] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 01/30/2017] [Indexed: 12/19/2022] Open
Abstract
Polydactyl zinc finger (ZF) proteins have prominent roles in gene regulation and often execute multiple regulatory functions. To understand how these proteins perform varied regulation, we studiedDrosophila Suppressor of Hairy-wing [Su(Hw)], an exemplar multifunctional polydactyl ZF protein. We identified separation-of-function (SOF) alleles that encode proteins disrupted in a single ZF that retain one of the Su(Hw) regulatory activities. Through extended in vitro analyses of the Su(Hw) ZF domain, we show that clusters of ZFs bind individual modules within a compound DNA consensus sequence. Through in vivo analysis of SOF mutants, we find that Su(Hw) genomic sites separate into sequence subclasses comprised of combinations of modules, with subclasses enriched for different chromatin features. These data suggest a Su(Hw) code, wherein DNA binding dictates its cofactor recruitment and regulatory output. We propose that similar DNA codes might be used to confer multiple regulatory functions of other polydactyl ZF proteins.
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Affiliation(s)
- Ryan M Baxley
- Interdisciplinary Graduate Program in Molecular and Cellular Biology, University of Iowa, Iowa City, IA 52242, USA
| | - James D Bullard
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Michael W Klein
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Ashley G Fell
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | | | - Tingting Duan
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Pamela K Geyer
- Interdisciplinary Graduate Program in Molecular and Cellular Biology, University of Iowa, Iowa City, IA 52242, USA.,Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
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8
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Identifying low density lipoprotein cholesterol associated variants in the Annexin A2 (ANXA2) gene. Atherosclerosis 2017; 261:60-68. [PMID: 28456096 PMCID: PMC5446264 DOI: 10.1016/j.atherosclerosis.2017.04.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/24/2017] [Accepted: 04/12/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND AIMS Annexin-A2 (AnxA2) is an endogenous inhibitor of proprotein convertase subtilisin/kexin type-9 (PCSK9). The repeat-one (R1) domain of AnxA2 binds to PCSK9, blocking its ability to promote degradation of low-density lipoprotein cholesterol-receptors (LDL-R) and thereby regulate low-density lipoprotein cholesterol (LDL-C) levels. Here we identify variants in ANXA2 influencing LDL-C levels and we determine the molecular mechanisms of their effects. RESULTS The ANXA2 single nucleotide polymorphism (SNP) genotype-phenotype association was examined using the Second-Northwick-Park Heart Study (NPHSII) (n∼2700) and the UCL-LSHTM-Edinburgh-Bristol (UCLEB) consortium (n∼14,600). The ANXA2-R1 domain coding-SNP rs17845226 (V98L) associated with LDL-C, homozygotes for the minor allele having ≈18.8% higher levels of LDL-C (p = 0.004), and higher risk of coronary heart disease (CHD) (p = 0.04). The SNP is in modest linkage disequilibrium (r2 > 0.5) with two intergenic SNPs, rs17191344 and rs11633032. Both SNPs showed allele-specific protein binding, and the minor alleles caused significant reduction in reporter gene expression (≈18%, p < 0.001). In the expression quantitative trait loci (eQTL) study, minor allele homozygotes have significantly lower levels of ANXA2-mRNA expression (p = 1.36 × 10-05). CONCLUSIONS Both rs11633032 and rs17191344 SNPs are functional variants, where the minor alleles create repressor-binding protein sites for transcription factors that contribute to reduced ANXA2 gene expression. Lower AnxA2 levels could increase plasma levels of PCSK9 and thus increase LDL-C levels and risk of CHD. This supports, for the first time in humans, previous observations in mouse models that changes in the levels of AnxA2 directly influence plasma LDL-C levels, and thus implicate this protein as a potential therapeutic target for LDL-C lowering.
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Li C, Hong T, Webb CH, Karner H, Sun S, Nie Q. A self-enhanced transport mechanism through long noncoding RNAs for X chromosome inactivation. Sci Rep 2016; 6:31517. [PMID: 27527711 PMCID: PMC4985753 DOI: 10.1038/srep31517] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 07/21/2016] [Indexed: 11/09/2022] Open
Abstract
X-chromosome inactivation (XCI) is the mammalian dosage compensation strategy for balancing sex chromosome content between females and males. While works exist on initiation of symmetric breaking, the underlying allelic choice mechanisms and dynamic regulation responsible for the asymmetric fate determination of XCI remain elusive. Here we combine mathematical modeling and experimental data to examine the mechanism of XCI fate decision by analyzing the signaling regulatory circuit associated with long noncoding RNAs (lncRNAs) involved in XCI. We describe three plausible gene network models that incorporate features of lncRNAs in their localized actions and rapid transcriptional turnovers. In particular, we show experimentally that Jpx (a lncRNA) is transcribed biallelically, escapes XCI, and is asymmetrically dispersed between two X's. Subjecting Jpx to our test of model predictions against previous experimental observations, we identify that a self-enhanced transport feedback mechanism is critical to XCI fate decision. In addition, the analysis indicates that an ultrasensitive response of Jpx signal on CTCF is important in this mechanism. Overall, our combined modeling and experimental data suggest that the self-enhanced transport regulation based on allele-specific nature of lncRNAs and their temporal dynamics provides a robust and novel mechanism for bi-directional fate decisions in critical developmental processes.
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Affiliation(s)
- Chunhe Li
- Department of Mathematics, University of California, Irvine, Irvine, CA 92697, USA
- Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697, USA
| | - Tian Hong
- Department of Mathematics, University of California, Irvine, Irvine, CA 92697, USA
- Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697, USA
| | - Chiu-Ho Webb
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Heather Karner
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Sha Sun
- Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697, USA
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Qing Nie
- Department of Mathematics, University of California, Irvine, Irvine, CA 92697, USA
- Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697, USA
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
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10
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Kotova ES, Akopov SB, Didych DA, Petrova NV, Iarovaia OV, Razin SV, Nikolaev LG. Binding of Protein Factor CTCF within Chicken Genome Alpha-Globin Locus. Acta Naturae 2016; 8:90-7. [PMID: 27099788 PMCID: PMC4837575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A systematic search for DNA fragments containing potential CTCF transcription factor binding sites in the chicken alpha-globin domain and its flanking regions was performed by means of the two-dimension electrophoretic mobility shift assay. For the alpha-globin domain fragments selected, the occupancy by the CTCF in erythroid and lymphoid chicken cells was tested by chromatin immunoprecipitation. Only one of 13 DNA fragments capable of CTCF binding in vitro was efficiently bound to this protein in vivo in erythroid cells, and somewhat less efficiently - in lymphoid cells. So, binding of CTCF to the DNA fragment in vitro in most cases does not mean that this fragment will be occupied by CTCF in the cell nucleus. Yet, CTCF binding in vivo, as a rule, is accompanied by the binding of the protein to this DNA region in vitro. During the erythroid differentiation, no significant changes in CTCF binding to the DNA fragments studied were detected.
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Affiliation(s)
- E. S. Kotova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya St., Moscow 117997, Russia
| | - S. B. Akopov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya St., Moscow 117997, Russia
| | - D. A. Didych
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya St., Moscow 117997, Russia
| | - N. V. Petrova
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - O. V. Iarovaia
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - S. V. Razin
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - L. G. Nikolaev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya St., Moscow 117997, Russia
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11
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Harr JC, Luperchio TR, Wong X, Cohen E, Wheelan SJ, Reddy KL. Directed targeting of chromatin to the nuclear lamina is mediated by chromatin state and A-type lamins. ACTA ACUST UNITED AC 2015; 208:33-52. [PMID: 25559185 PMCID: PMC4284222 DOI: 10.1083/jcb.201405110] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nuclear organization has been implicated in regulating gene activity. Recently, large developmentally regulated regions of the genome dynamically associated with the nuclear lamina have been identified. However, little is known about how these lamina-associated domains (LADs) are directed to the nuclear lamina. We use our tagged chromosomal insertion site system to identify small sequences from borders of fibroblast-specific variable LADs that are sufficient to target these ectopic sites to the nuclear periphery. We identify YY1 (Ying-Yang1) binding sites as enriched in relocating sequences. Knockdown of YY1 or lamin A/C, but not lamin A, led to a loss of lamina association. In addition, targeted recruitment of YY1 proteins facilitated ectopic LAD formation dependent on histone H3 lysine 27 trimethylation and histone H3 lysine di- and trimethylation. Our results also reveal that endogenous loci appear to be dependent on lamin A/C, YY1, H3K27me3, and H3K9me2/3 for maintenance of lamina-proximal positioning.
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Affiliation(s)
- Jennifer C Harr
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Teresa Romeo Luperchio
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Xianrong Wong
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Erez Cohen
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Sarah J Wheelan
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Karen L Reddy
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
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12
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Choi I, Kim R, Lim HW, Kaestner KH, Won KJ. 5-hydroxymethylcytosine represses the activity of enhancers in embryonic stem cells: a new epigenetic signature for gene regulation. BMC Genomics 2014; 15:670. [PMID: 25106691 PMCID: PMC4133056 DOI: 10.1186/1471-2164-15-670] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 07/31/2014] [Indexed: 02/08/2023] Open
Abstract
Background Recent mapping of 5-hydroxymethylcytosine (5hmC) provides a genome-wide view of the distribution of this important chromatin mark. However, the role of 5hmC in specific regulatory regions is not clear, especially at enhancers. Results We found a group of distal transcription factor binding sites highly enriched for 5-hdroxymethylcytosine (5hmC), but lacking any known activating histone marks and being depleted for nascent transcripts, suggesting a repressive role for 5hmC in mouse embryonic stem cells (mESCs). 5-formylcytosine (5fC), which is known to mark poised enhancers where H3K4me1 is enriched, is also observed at these sites. Furthermore, the 5hmC levels were inversely correlated with RNA polymerase II (PolII) occupancy in mESCs as well as in fully differentiated adipocytes. Interestingly, activating H3K4me1/2 histone marks were enriched at these sites when the associated genes become activated following lineage specification. These putative enhancers were shown to be functional in embryonic stem cells when unmethylated. Together, these data suggest that 5hmC suppresses the activity of this group of enhancers, which we termed “silenced enhancers”. Conclusions Our findings indicate that 5hmC has a repressive role at specific proximal and distal regulatory regions in mESCs, and suggest that 5hmC is a new epigenetic mark for silenced enhancers. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-670) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Klaus H Kaestner
- Department of Genetics, Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, 3400 Civic Center Blvd, 19104 Philadelphia, PA, USA.
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Maksimenko O, Kyrchanova O, Bonchuk A, Stakhov V, Parshikov A, Georgiev P. Highly conserved ENY2/Sus1 protein binds to Drosophila CTCF and is required for barrier activity. Epigenetics 2014; 9:1261-70. [PMID: 25147918 DOI: 10.4161/epi.32086] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Chromatin insulators affect interactions between promoters and enhancers/silencers and function as barriers for the spreading of repressive chromatin. Drosophila insulator protein dCTCF marks active promoters and boundaries of many histone H3K27 trimethylation domains associated with repressed chromatin. In particular, dCTCF binds to such boundaries between the parasegment-specific regulatory domains of the Bithorax complex. Here we demonstrate that the evolutionarily conserved protein ENY2 is recruited to the zinc-finger domain of dCTCF and is required for the barrier activity of dCTCF-dependent insulators in transgenic lines. Inactivation of ENY2 by RNAi in BG3 cells leads to the spreading of H3K27 trimethylation and Pc protein at several dCTCF boundaries. The results suggest that evolutionarily conserved ENY2 is responsible for barrier activity mediated by the dCTCF protein.
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Affiliation(s)
- Oksana Maksimenko
- Laboratory of Gene Expression Regulation in Development; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Olga Kyrchanova
- Group of Transcriptional Regulation; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Artem Bonchuk
- Group of Transcriptional Regulation; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Viacheslav Stakhov
- Laboratory of Gene Expression Regulation in Development; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Alexander Parshikov
- Department of the Control of Genetic Processes; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
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Kotova ES, Sorokina IV, Akopov SB, Nikolaev LG, Sverdlov ED. Expression of chicken CTCF gene in COS-1 cells and partial purification of CTCF protein. BIOCHEMISTRY (MOSCOW) 2014; 78:879-83. [PMID: 24228875 DOI: 10.1134/s0006297913080038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The chicken gene for transcription factor CTCF was expressed in COS-1 mammalian cells. The CTCF protein containing polyhistidine tag was partially purified using metallo-affinity and ion-exchange chromatography. The expressed protein localized in the cell nucleus and was shown to be functionally active in the electrophoretic mobility shift assay and specifically interacted with anti-CTCF antibodies.
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Affiliation(s)
- E S Kotova
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
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15
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Wood AM, Garza-Gongora AG, Kosak ST. A Crowdsourced nucleus: understanding nuclear organization in terms of dynamically networked protein function. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1839:178-90. [PMID: 24412853 PMCID: PMC3954575 DOI: 10.1016/j.bbagrm.2014.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/30/2013] [Accepted: 01/02/2014] [Indexed: 01/14/2023]
Abstract
The spatial organization of the nucleus results in a compartmentalized structure that affects all aspects of nuclear function. This compartmentalization involves genome organization as well as the formation of nuclear bodies and plays a role in many functions, including gene regulation, genome stability, replication, and RNA processing. Here we review the recent findings associated with the spatial organization of the nucleus and reveal that a common theme for nuclear proteins is their ability to participate in a variety of functions and pathways. We consider this multiplicity of function in terms of Crowdsourcing, a recent phenomenon in the world of information technology, and suggest that this model provides a novel way to synthesize the many intersections between nuclear organization and function. This article is part of a Special Issue entitled: Chromatin and epigenetic regulation of animal development.
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Affiliation(s)
- Ashley M Wood
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Arturo G Garza-Gongora
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Steven T Kosak
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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Smirnov NA, Didych DA, Akopov SB, Nikolaev LG, Sverdlov ED. Assay of insulator enhancer-blocking activity with the use of transient transfection. BIOCHEMISTRY (MOSCOW) 2013; 78:895-903. [PMID: 24228877 DOI: 10.1134/s0006297913080051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We used a transient transfection of cultured cells with linearized plasmids to analyze the enhancer-blocking activity of potential insulators including the standard cHS4 chicken beta-globin insulator and several DNA fragments selected from the human genome sequence. About 60-80% of the potential insulators do reveal the enhancer-blocking activity when probed by the transient transfection assay. The activity of different sequences is characterized by certain tissue specificity and by dependence on the orientation of the fragments relative to the promoter. Thus, the transfection model may be used for quantitative analysis of the enhancer-blocking activity of the potential insulators.
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Affiliation(s)
- N A Smirnov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
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CTCF occupation of the herpes simplex virus 1 genome is disrupted at early times postreactivation in a transcription-dependent manner. J Virol 2012; 86:12741-59. [PMID: 22973047 DOI: 10.1128/jvi.01655-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In herpes simplex virus 1 (HSV-1), binding clusters enriched in CTCF during latency have been previously identified. We hypothesized that CTCF binding to CTCF clusters in HSV-1 would be disrupted in a reactivation event. To investigate, CTCF occupation of three CTCF binding clusters in HSV-1 was analyzed following sodium butyrate (NaB)- and explant-induced reactivation in the mouse. Our data show that the CTCF domains positioned within the HSV-1 genome, specifically around the latency-associated transcript (LAT) and ICP0 and ICP4 regions of the genome, lose CTCF occupancy following the application of reactivation stimuli in wild-type virus. We also found that CTCF binding clusters upstream of the ICP0 and ICP4 promoters both function as classical insulators capable of acting as enhancer blockers of the LAT enhancer. Finally, our results suggest that CTCF occupation of domains in HSV-1 may be differentially regulated both during latency and at early times following reactivation by the presence of lytic transcripts and further implicate epigenetic regulation of HSV-1 as a critical component of the latency-reactivation transition.
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Didych DA, Kotova ES, Akopov SB, Nikolaev LG, Sverdlov ED. DNA fragments binding CTCF in vitro and in vivo are capable of blocking enhancer activity. BMC Res Notes 2012; 5:178. [PMID: 22480385 PMCID: PMC3369819 DOI: 10.1186/1756-0500-5-178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 04/05/2012] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Earlier we identified ten 100-300-bp long CTCF-binding DNA fragments selected earlier from a 1-Mb human chromosome 19 region. Here the positive-negative selection technique was used to check the ability of CTCF-binding human genomic fragments to block enhancer-promoter interaction when inserted into the genome. RESULTS Ten CTCF-binding DNA fragments were inserted between the CMV enhancer and CMV minimal promoter driving the herpes simplex virus thymidine kinase (HSV-tk) gene in a vector expressing also the neoR gene under a separate promoter. The constructs were then integrated into the genome of CHO cells, and the cells resistant to neomycin and ganciclovir (positive-negative selection) were picked up, and their DNAs were PCR analyzed to confirm the presence of the fragments between the enhancer and promoter in both orientations. CONCLUSIONS We demonstrated that all sequences identified by their CTCF binding both in vitro and in vivo had enhancer-blocking activity when inserted between the CMV minimal promoter and enhancer in stably transfected CHO cells.
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Affiliation(s)
- Dmitry A Didych
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya, Moscow 117997, Russia
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Soshnev AA, He B, Baxley RM, Jiang N, Hart CM, Tan K, Geyer PK. Genome-wide studies of the multi-zinc finger Drosophila Suppressor of Hairy-wing protein in the ovary. Nucleic Acids Res 2012; 40:5415-31. [PMID: 22406832 PMCID: PMC3384341 DOI: 10.1093/nar/gks225] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The Drosophila Suppressor of Hairy-wing [Su(Hw)] protein is a globally expressed, multi-zinc finger (ZnF) DNA-binding protein. Su(Hw) forms a classic insulator when bound to the gypsy retrotransposon and is essential for female germline development. These functions are genetically separable, as exemplified by Su(Hw)(f) that carries a defective ZnF10, causing a loss of insulator but not germline function. Here, we completed the first genome-wide analysis of Su(Hw)-binding sites (SBSs) in the ovary, showing that tissue-specific binding is not responsible for the restricted developmental requirements for Su(Hw). Mapping of ovary Su(Hw)(f) SBSs revealed that female fertility requires binding to only one third of the wild-type sites. We demonstrate that Su(Hw)(f) retention correlates with binding site affinity and partnership with Modifier of (mdg4) 67.2 protein. Finally, we identify clusters of co-regulated ovary genes flanked by Su(Hw)(f) bound sites and show that loss of Su(Hw) has limited effects on transcription of these genes. These data imply that the fertility function of Su(Hw) may not depend upon the demarcation of transcriptional domains. Our studies establish a framework for understanding the germline Su(Hw) function and provide insights into how chromatin occupancy is achieved by multi-ZnF proteins, the most common transcription factor class in metazoans.
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Affiliation(s)
- Alexey A Soshnev
- Interdisciplinary Program in Molecular and Cellular Biology, University of Iowa, Iowa City, IA 52242, USA
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Lamina C, Coassin S, Illig T, Kronenberg F. Look beyond one's own nose: combination of information from publicly available sources reveals an association of GATA4 polymorphisms with plasma triglycerides. Atherosclerosis 2011; 219:698-703. [PMID: 21945496 DOI: 10.1016/j.atherosclerosis.2011.08.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 08/26/2011] [Accepted: 08/30/2011] [Indexed: 12/31/2022]
Abstract
OBJECTIVE GATA4iKO mice exhibit impeded triglyceride absorption from intestine and decreased plasma triglyceride levels. Data in humans are lacking. We hypothesized that triglyceride levels might also be regulated by polymorphisms in the GATA4 gene in humans. We used publicly available data from different sources to evaluate this hypothesis. Our approach is a more often applicable advance to uncover associations and their functional implications which would have been otherwise missed by standard genome-wide association studies (GWAS). METHODS We used the publicly available GWAS results from 137 SNPs in the GATA4 region for triglyceride levels. We embedded these results into the comprehensive functional genomics data provided in the UCSC Genome Browser including among others information on regulatory elements and interspecies conservation. A concise graphical presentation is proposed together with an R function for automatic data preparation. This process is presented in an educational manner using a screencast to become most useful for other researchers. RESULTS We observed several polymorphisms in and around the GATA4 gene which have a significant influence on plasma triglyceride levels with the lowest p-value at SNP rs1466785 (Bonferroni-corrected p-value = 1.76e-5). The bioinformatic evaluation of this locus in publicly available functional genomics data provided converging evidence for the presence of a transcriptional regulator downstream of GATA4. CONCLUSION The combination of different sources of data has revealed an association of GATA4 with triglyceride levels in humans. Our evaluation exemplifies how an integrative analysis including both statistical and biological perspectives can shed new light on available association data and reveals novel candidate genes, which are otherwise hidden in the noisy region below genome-wide significance.
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Affiliation(s)
- Claudia Lamina
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
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Understanding the molecular circuitry of cell lineage specification in the early mouse embryo. Genes (Basel) 2011; 2:420-48. [PMID: 24710206 PMCID: PMC3927619 DOI: 10.3390/genes2030420] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 06/24/2011] [Accepted: 07/05/2011] [Indexed: 11/16/2022] Open
Abstract
Pluripotent stem cells hold great promise for cell-based therapies in regenerative medicine. However, critical to understanding and exploiting mechanisms of cell lineage specification, epigenetic reprogramming, and the optimal environment for maintaining and differentiating pluripotent stem cells is a fundamental knowledge of how these events occur in normal embryogenesis. The early mouse embryo has provided an excellent model to interrogate events crucial in cell lineage commitment and plasticity, as well as for embryo-derived lineage-specific stem cells and induced pluripotent stem (iPS) cells. Here we provide an overview of cell lineage specification in the early (preimplantation) mouse embryo focusing on the transcriptional circuitry and epigenetic marks necessary for successive differentiation events leading to the formation of the blastocyst.
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Sorotokina AN, Chernov IP, Stukacheva EA, Nikolaev LG, Sverdlov ED. [Enhancer activity of DNA fragments from FXYD5-COX7A region of human chromosome 19]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2011; 37:244-52. [PMID: 21721257 DOI: 10.1134/s1068162011020142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The enhancer activity of four previously identified within the one megabase region of human chromosome 19 DNA fragments was investigated. All four fragments had similar tissue-specific profile--maximum of enhancer activity was observed in HEK293 and minimum in HeLa cells. Enhancers obtained had pronounced specificity toward cytomegalovirus promoter compared with SV40 promoter. Functional dissection of one of the fragments (enhancer 14) demonstrated that only its inner 127 b.p. part possessed enhancer activity. The negative regulators, i.e. silencers or insulators are probably located in flanking regions of enhancer 14 and limit its effect on promoter. At the same time, enhancer activity of enhancer 14 depends on its orientation relative to promoter that isn't typical to majority of enhancer elements. Inner 127 b.p. fragment contains 11 transcription factor binding sites; 8 of them are factors that take part in immune system regulation. Enhancer 14 is located 500 b.p. upstream of transcription start site of TYROBP (DAP12) gene that codes for of T-killer cells activator protein and possibly functions as tissue-specific enhancer for this gene.
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Spudich GM, Fernández-Suárez XM. Disease and phenotype data at Ensembl. CURRENT PROTOCOLS IN HUMAN GENETICS 2011; Chapter 6:Unit 6.11. [PMID: 21400687 PMCID: PMC3099348 DOI: 10.1002/0471142905.hg0611s69] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Biological databases are an important resource for the life sciences community. Accessing the hundreds of databases supporting molecular biology and related fields is a daunting and time-consuming task. Integrating this information into one access point is a necessity for the life sciences community, which includes researchers focusing on human disease. Here we discuss the Ensembl genome browser, which acts as a single entry point with Graphical User Interface to data from multiple projects, including OMIM, dbSNP, and the NHGRI GWAS catalog. Ensembl provides a comprehensive source of annotation for the human genome, along with other species of biomedical interest. In this unit, we explore how to use the Ensembl genome browser in example queries related to human genetic diseases. Support protocols demonstrate quick sequence export using the BioMart tool.
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Schaack J, Qiao L, Walkiewicz MP, Stonehouse M, Engel DA, Vazquez-Torres A, Nordeen SK, Shao J, Moorhead JW. Insertion of CTCF-binding sites into a first-generation adenovirus vector reduces the innate inflammatory response and prolongs transgene expression. Virology 2011; 412:136-45. [DOI: 10.1016/j.virol.2010.12.053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 12/21/2010] [Accepted: 12/27/2010] [Indexed: 10/18/2022]
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Abstract
Cohesin is a conserved multisubunit protein complex with diverse cellular roles, making key contributions to the coordination of chromosome segregation, the DNA damage response and chromatin regulation by epigenetic mechanisms. Much has been learned in recent years about the roles of cohesin in a physiological context, whereas its potential and emerging role in tumour initiation and/or progression has received relatively little attention. In this Opinion article we examine how cohesin deregulation could contribute to cancer development on the basis of its physiological roles.
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Affiliation(s)
- Huiling Xu
- Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria 8006, Australia
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