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Zhou H, Huang Y, Jia C, Pang Y, Liu L, Xu Y, Jin P, Qian J, Ma F. NF-κB factors cooperate with Su(Hw)/E4F1 to balance Drosophila/human immune responses via modulating dynamic expression of miR-210. Nucleic Acids Res 2024; 52:6906-6927. [PMID: 38742642 PMCID: PMC11229355 DOI: 10.1093/nar/gkae394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/25/2024] [Accepted: 04/30/2024] [Indexed: 05/16/2024] Open
Abstract
MicroRNAs (miRNAs) play crucial regulatory roles in controlling immune responses, but their dynamic expression mechanisms are poorly understood. Here, we firstly confirm that the conserved miRNA miR-210 negatively regulates innate immune responses of Drosophila and human via targeting Toll and TLR6, respectively. Secondly, our findings demonstrate that the expression of miR-210 is dynamically regulated by NF-κB factor Dorsal in immune response of Drosophila Toll pathway. Thirdly, we find that Dorsal-mediated transcriptional inhibition of miR-210 is dependent on the transcriptional repressor Su(Hw). Mechanistically, Dorsal interacts with Su(Hw) to modulate cooperatively the dynamic expression of miR-210 in a time- and dose-dependent manner, thereby controlling the strength of Drosophila Toll immune response and maintaining immune homeostasis. Fourthly, we reveal a similar mechanism in human cells, where NF-κB/RelA cooperates with E4F1 to regulate the dynamic expression of hsa-miR-210 in the TLR immune response. Overall, our study reveals a conservative regulatory mechanism that maintains animal innate immune homeostasis and provides new insights into the dynamic regulation of miRNA expression in immune response.
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Affiliation(s)
- Hongjian Zhou
- Laboratory for Comparative Genomics and Bioinformatics & Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
- Institute of Laboratory Medicine, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, 210002 Nanjing, Jiangsu, China
| | - Yu Huang
- Laboratory for Comparative Genomics and Bioinformatics & Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
| | - Chaolong Jia
- Laboratory for Comparative Genomics and Bioinformatics & Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
| | - Yujia Pang
- Laboratory for Comparative Genomics and Bioinformatics & Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
- Institute of Laboratory Medicine, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, 210002 Nanjing, Jiangsu, China
| | - Li Liu
- Laboratory for Comparative Genomics and Bioinformatics & Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
| | - Yina Xu
- Laboratory for Comparative Genomics and Bioinformatics & Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
| | - Ping Jin
- Laboratory for Comparative Genomics and Bioinformatics & Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
| | - Jinjun Qian
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, 210023 Nanjing, Jiangsu, China
| | - Fei Ma
- Laboratory for Comparative Genomics and Bioinformatics & Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, China
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2
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Melnikova LS, Molodina VV, Georgiev PG, Golovnin AK. Role of Mod(mdg4)-67.2 Protein in Interactions between Su(Hw)-Dependent Complexes and Their Recruitment to Chromatin. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:626-636. [PMID: 38831500 DOI: 10.1134/s0006297924040035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 06/05/2024]
Abstract
Su(Hw) belongs to the class of proteins that organize chromosome architecture, determine promoter activity, and participate in formation of the boundaries/insulators between the regulatory domains. This protein contains a cluster of 12 zinc fingers of the C2H2 type, some of which are responsible for binding to the consensus site. The Su(Hw) protein forms complex with the Mod(mdg4)-67.2 and the CP190 proteins, where the last one binds to all known Drosophila insulators. To further study functioning of the Su(Hw)-dependent complexes, we used the previously described su(Hw)E8 mutation with inactive seventh zinc finger, which produces mutant protein that cannot bind to the consensus site. The present work shows that the Su(Hw)E8 protein continues to directly interact with the CP190 and Mod(mdg4)-67.2 proteins. Through interaction with Mod(mdg4)-67.2, the Su(Hw)E8 protein can be recruited into the Su(Hw)-dependent complexes formed on chromatin and enhance their insulator activity. Our results demonstrate that the Su(Hw) dependent complexes without bound DNA can be recruited to the Su(Hw) binding sites through the specific protein-protein interactions that are stabilized by Mod(mdg4)-67.2.
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Affiliation(s)
- Larisa S Melnikova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
| | - Varvara V Molodina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Pavel G Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Anton K Golovnin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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3
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Vdovina YA, Georgieva SG, Kopytova DV. Interaction of mRNA with the C-Terminal Domain of PCID2, a Subunit of the TREX-2 Complex, Is Required for Its Export from the Nucleus to the Cytoplasm in Drosophila melanogaster. DOKL BIOCHEM BIOPHYS 2023; 513:328-331. [PMID: 38066318 PMCID: PMC10810031 DOI: 10.1134/s1607672923700527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/08/2023] [Accepted: 09/08/2023] [Indexed: 01/26/2024]
Abstract
Following the transcription step, the newly synthesized mRNA is exported from the nucleus to the cytoplasm and further to the translation site. The TREX-2 complex is involved in the step of mRNA export from the nucleus to the cytoplasm. This complex in Drosophila melanogaster consists of four proteins: Xmas-2, PCID2, ENY2, and Sem1p. In our work, we have shown that deletion of the C-terminal sequence of PCID2 leads to a decrease in the interaction of the protein with RNA and to impaired mRNA export from the nucleus to the cytoplasm in D. melanogaster.
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Affiliation(s)
- Yu A Vdovina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.
| | - S G Georgieva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - D V Kopytova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.
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4
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Melnikova L, Golovnin A. Multiple Roles of dXNP and dADD1- Drosophila Orthologs of ATRX Chromatin Remodeler. Int J Mol Sci 2023; 24:16486. [PMID: 38003676 PMCID: PMC10671109 DOI: 10.3390/ijms242216486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/11/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023] Open
Abstract
The Drosophila melanogaster dADD1 and dXNP proteins are orthologues of the ADD and SNF2 domains of the vertebrate ATRX (Alpha-Thalassemia with mental Retardation X-related) protein. ATRX plays a role in general molecular processes, such as regulating chromatin status and gene expression, while dADD1 and dXNP have similar functions in the Drosophila genome. Both ATRX and dADD1/dXNP interact with various protein partners and participate in various regulatory complexes. Disruption of ATRX expression in humans leads to the development of α-thalassemia and cancer, especially glioma. However, the mechanisms that allow ATRX to regulate various cellular processes are poorly understood. Studying the functioning of dADD1/dXNP in the Drosophila model may contribute to understanding the mechanisms underlying the multifunctional action of ATRX and its connection with various cellular processes. This review provides a brief overview of the currently available information in mammals and Drosophila regarding the roles of ATRX, dXNP, and dADD1. It discusses possible mechanisms of action of complexes involving these proteins.
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Affiliation(s)
- Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| | - Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
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5
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Tang M, Chen J, Zeng T, Ye DM, Li YK, Zou J, Zhang YP. Systemic analysis of the DNA replication regulator origin recognition complex in lung adenocarcinomas identifies prognostic and expression significance. Cancer Med 2023; 12:5035-5054. [PMID: 36205357 PMCID: PMC9972100 DOI: 10.1002/cam4.5238] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/30/2022] [Accepted: 09/01/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND DNA replication alteration is a hallmark of patients with lung adenocarcinoma (LUAD) and is frequently observed in LUAD progression. Origin recognition complex (ORC) 1, ORC2, ORC3, ORC4, ORC5, and ORC6 form a replication-initiator complex to mediate DNA replication, which plays a key role in carcinogenesis, while their roles in LUAD remain poorly understood. METHODS The mRNA and protein expression of ORCs was confirmed by the GEPIA, HPA, CPTAC, and TCGA databases. The protein-protein interaction network was analyzed by the GeneMANIA database. Functional enrichment was confirmed by the Metascape database. The effects of ORCs on immune infiltration were validated by the TIMER database. The prognostic significance of ORCs in LUAD was confirmed by the KM-plot and GENT2 databases. DNA alteration and protein structure were determined in the cBioProtal and PDB databases. Moreover, the protein expression and prognostic value of ORCs were confirmed in our LUAD data sets by immunohistochemistry (IHC) staining. RESULTS ORC mRNA and protein were significantly increased in patients with LUAD compared with corresponding normal tissue samples. The results of IHC staining analysis were similar result to those of the above bioinformatics analysis. Furthermore, ORC1 and ORC6 had significant prognostic values for LUAD patients. Furthermore, the ORC cooperatively promoted LUAD development by driving DNA replication, cellular senescence, and metabolic processes. CONCLUSION The ORC, especially ORC1/6, has important prognostic and expression significance for LUAD patients.
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Affiliation(s)
- Min Tang
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of University of South China, Hengyang, Hunan, People's Republic of China
| | - Juan Chen
- Department of Radiotherapy, The Second Affiliated Hospital of University of South China, Hengyang, Hunan, People's Republic of China
| | - Tian Zeng
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan, People's Republic of China
| | - Dong-Mei Ye
- Department of Pathology, The First Hospital of Nanchang City, Nanchang, Jiangxi, People's Republic of China
| | - Yu-Kun Li
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan, People's Republic of China
| | - Juan Zou
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan, People's Republic of China
| | - Yu-Ping Zhang
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of University of South China, Hengyang, Hunan, People's Republic of China
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6
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Chen S, Rosin LF, Pegoraro G, Moshkovich N, Murphy PJ, Yu G, Lei EP. NURF301 contributes to gypsy chromatin insulator-mediated nuclear organization. Nucleic Acids Res 2022; 50:7906-7924. [PMID: 35819192 PMCID: PMC9371915 DOI: 10.1093/nar/gkac600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/26/2022] [Accepted: 06/29/2022] [Indexed: 11/14/2022] Open
Abstract
Chromatin insulators are DNA-protein complexes that can prevent the spread of repressive chromatin and block communication between enhancers and promoters to regulate gene expression. In Drosophila, the gypsy chromatin insulator complex consists of three core proteins: CP190, Su(Hw), and Mod(mdg4)67.2. These factors concentrate at nuclear foci termed insulator bodies, and changes in insulator body localization have been observed in mutants defective for insulator function. Here, we identified NURF301/E(bx), a nucleosome remodeling factor, as a novel regulator of gypsy insulator body localization through a high-throughput RNAi imaging screen. NURF301 promotes gypsy-dependent insulator barrier activity and physically interacts with gypsy insulator proteins. Using ChIP-seq, we found that NURF301 co-localizes with insulator proteins genome-wide, and NURF301 promotes chromatin association of Su(Hw) and CP190 at gypsy insulator binding sites. These effects correlate with NURF301-dependent nucleosome repositioning. At the same time, CP190 and Su(Hw) both facilitate recruitment of NURF301 to chromatin. Finally, Oligopaint FISH combined with immunofluorescence revealed that NURF301 promotes 3D contact between insulator bodies and gypsy insulator DNA binding sites, and NURF301 is required for proper nuclear positioning of gypsy binding sites. Our data provide new insights into how a nucleosome remodeling factor and insulator proteins cooperatively contribute to nuclear organization.
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Affiliation(s)
- Shue Chen
- Nuclear Organization and Gene Expression Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.,Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Leah F Rosin
- Nuclear Organization and Gene Expression Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.,Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Gianluca Pegoraro
- High-Throughput Imaging Facility (HiTIF), Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Nellie Moshkovich
- Nuclear Organization and Gene Expression Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.,Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Patrick J Murphy
- Nuclear Organization and Gene Expression Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.,Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Guoyun Yu
- Nuclear Organization and Gene Expression Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.,Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Elissa P Lei
- Nuclear Organization and Gene Expression Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.,Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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7
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Nikolenko JV, Fursova NA, Mazina MY, Vorobyeva NE, Krasnov AN. The Drosophila CG9890 Protein is Involved in the Regulation of Ecdysone-Dependent Transcription. Mol Biol 2022. [DOI: 10.1134/s0026893322040082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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8
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Stow EC, Simmons JR, An R, Schoborg TA, Davenport NM, Labrador M. A Drosophila insulator interacting protein suppresses enhancer-blocking function and modulates replication timing. Gene 2022; 819:146208. [PMID: 35092858 DOI: 10.1016/j.gene.2022.146208] [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: 05/11/2021] [Revised: 12/17/2021] [Accepted: 01/13/2022] [Indexed: 01/02/2023]
Abstract
Insulators play important roles in genome structure and function in eukaryotes. Interactions between a DNA binding insulator protein and its interacting partner proteins define the properties of each insulator site. The different roles of insulator protein partners in the Drosophila genome and how they confer functional specificity remain poorly understood. The Suppressor of Hairy wing [Su(Hw)] insulator is targeted to the nuclear lamina, preferentially localizes at euchromatin/heterochromatin boundaries, and is associated with the gypsy retrotransposon. Insulator activity relies on the ability of the Su(Hw) protein to bind the DNA at specific sites and interact with Mod(mdg4)67.2 and CP190 partner proteins. HP1 and insulator partner protein 1 (HIPP1) is a partner of Su(Hw), but how HIPP1 contributes to the function of Su(Hw) insulator complexes is unclear. Here, we demonstrate that HIPP1 colocalizes with the Su(Hw) insulator complex in polytene chromatin and in stress-induced insulator bodies. We find that the overexpression of either HIPP1 or Su(Hw) or mutation of the HIPP1 crotonase-like domain (CLD) causes defects in cell proliferation by limiting the progression of DNA replication. We also show that HIPP1 overexpression suppresses the Su(Hw) insulator enhancer-blocking function, while mutation of the HIPP1 CLD does not affect Su(Hw) enhancer blocking. These findings demonstrate a functional relationship between HIPP1 and the Su(Hw) insulator complex and suggest that the CLD, while not involved in enhancer blocking, influences cell cycle progression.
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Affiliation(s)
- Emily C Stow
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996, USA
| | - James R Simmons
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996, USA
| | - Ran An
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996, USA
| | - Todd A Schoborg
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996, USA
| | - Nastasya M Davenport
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996, USA
| | - Mariano Labrador
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996, USA.
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9
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Su(Hw) primes 66D and 7F Drosophila chorion genes loci for amplification through chromatin decondensation. Sci Rep 2021; 11:16963. [PMID: 34417521 PMCID: PMC8379230 DOI: 10.1038/s41598-021-96488-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 08/11/2021] [Indexed: 11/11/2022] Open
Abstract
Suppressor of Hairy wing [Su(Hw)] is an insulator protein that participates in regulating chromatin architecture and gene repression in Drosophila. In previous studies we have shown that Su(Hw) is also required for pre-replication complex (pre-RC) recruitment on Su(Hw)-bound sites (SBSs) in Drosophila S2 cells and pupa. Here, we describe the effect of Su(Hw) on developmentally regulated amplification of 66D and 7F Drosophila amplicons in follicle cells (DAFCs), widely used as models in replication studies. We show Su(Hw) binding co-localizes with all known DAFCs in Drosophila ovaries, whereas disruption of Su(Hw) binding to 66D and 7F DAFCs causes a two-fold decrease in the amplification of these loci. The complete loss of Su(Hw) binding to chromatin impairs pre-RC recruitment to all amplification regulatory regions of 66D and 7F loci at early oogenesis (prior to DAFCs amplification). These changes coincide with a considerable Su(Hw)-dependent condensation of chromatin at 66D and 7F loci. Although we observed the Brm, ISWI, Mi-2, and CHD1 chromatin remodelers at SBSs genome wide, their remodeler activity does not appear to be responsible for chromatin decondensation at the 66D and 7F amplification regulatory regions. We have discovered that, in addition to the CBP/Nejire and Chameau histone acetyltransferases, the Gcn5 acetyltransferase binds to 66D and 7F DAFCs at SBSs and this binding is dependent on Su(Hw). We propose that the main function of Su(Hw) in developmental amplification of 66D and 7F DAFCs is to establish a chromatin structure that is permissive to pre-RC recruitment.
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10
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Peterson SC, Samuelson KB, Hanlon SL. Multi-Scale Organization of the Drosophila melanogaster Genome. Genes (Basel) 2021; 12:817. [PMID: 34071789 PMCID: PMC8228293 DOI: 10.3390/genes12060817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/21/2021] [Accepted: 05/26/2021] [Indexed: 12/16/2022] Open
Abstract
Interphase chromatin, despite its appearance, is a highly organized framework of loops and bends. Chromosomes are folded into topologically associating domains, or TADs, and each chromosome and its homolog occupy a distinct territory within the nucleus. In Drosophila, genome organization is exceptional because homologous chromosome pairing is in both germline and somatic tissues, which promote interhomolog interactions such as transvection that can affect gene expression in trans. In this review, we focus on what is known about genome organization in Drosophila and discuss it from TADs to territory. We start by examining intrachromosomal organization at the sub-chromosome level into TADs, followed by a comprehensive analysis of the known proteins that play a key role in TAD formation and boundary establishment. We then zoom out to examine interhomolog interactions such as pairing and transvection that are abundant in Drosophila but rare in other model systems. Finally, we discuss chromosome territories that form within the nucleus, resulting in a complete picture of the multi-scale organization of the Drosophila genome.
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Affiliation(s)
| | | | - Stacey L. Hanlon
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; (S.C.P.); (K.B.S.)
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11
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Glukhova AA, Kurshakova MM, Nabirochkina EN, Georgieva SG, Kopytova DV. PCID2, a subunit of the Drosophila TREX-2 nuclear export complex, is essential for both mRNA nuclear export and its subsequent cytoplasmic trafficking. RNA Biol 2021; 18:1969-1980. [PMID: 33602059 DOI: 10.1080/15476286.2021.1885198] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The TREX-2 complex is essential for the general nuclear mRNA export in eukaryotes. TREX-2 interacts with the nuclear pore and transcriptional apparatus and links transcription to the mRNA export. However, it remains poorly understood how the TREX-2-dependent nuclear export is connected to the subsequent stages of mRNA trafficking. Here, we show that the PCID2 subunit of Drosophila TREX-2 is present in the cytoplasm of the cell. The cytoplasmic PCID2 directly interacts with the NudC protein and this interaction maintains its stability in the cytoplasm. Moreover, PCID2 is associated with the cytoplasmic mRNA and microtubules. The PCID2 knockdown blocks nuclear export of mRNA and also affects the general mRNA transport into the cytoplasm. These data suggest that PCID2 could be the link between the nuclear TREX-2-dependent export and the subsequent cytoplasmic trafficking of mRNA.
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Affiliation(s)
- A A Glukhova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - M M Kurshakova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - E N Nabirochkina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - S G Georgieva
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - D V Kopytova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
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12
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Martin PC, Zabet NR. Dissecting the binding mechanisms of transcription factors to DNA using a statistical thermodynamics framework. Comput Struct Biotechnol J 2020; 18:3590-3605. [PMID: 33304457 PMCID: PMC7708957 DOI: 10.1016/j.csbj.2020.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 01/22/2023] Open
Abstract
Transcription Factors (TFs) bind to DNA and control activity of target genes. Here, we present ChIPanalyser, a user-friendly, versatile and powerful R/Bioconductor package predicting and modelling the binding of TFs to DNA. ChIPanalyser performs similarly to state-of-the-art tools, but is an explainable model and provides biological insights into binding mechanisms of TFs. We focused on investigating the binding mechanisms of three TFs that are known architectural proteins CTCF, BEAF-32 and su(Hw) in three Drosophila cell lines (BG3, Kc167 and S2). While CTCF preferentially binds only to a subset of high affinity sites located mainly in open chromatin, BEAF-32 binds to most of its high affinity binding sites available in open chromatin. In contrast, su(Hw) binds to both open chromatin and also partially closed chromatin. Most importantly, differences in TF binding profiles between cell lines for these TFs are mainly driven by differences in DNA accessibility and not by differences in TF concentrations between cell lines. Finally, we investigated binding of Hox TFs in Drosophila and found that Ubx binds only in open chromatin, while Abd-B and Dfd are capable to bind in both open and partially closed chromatin. Overall, our results show that TFs display different binding mechanisms and that our model is able to recapitulate their specific binding behaviour.
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Affiliation(s)
- Patrick C.N. Martin
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, UK
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Nicolae Radu Zabet
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, UK
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
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13
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Melnikova LS, Georgiev PG, Golovnin AK. The Functions and Mechanisms of Action of Insulators in the Genomes of Higher Eukaryotes. Acta Naturae 2020; 12:15-33. [PMID: 33456975 PMCID: PMC7800606 DOI: 10.32607/actanaturae.11144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/12/2020] [Indexed: 12/22/2022] Open
Abstract
The mechanisms underlying long-range interactions between chromatin regions and the principles of chromosomal architecture formation are currently under extensive scrutiny. A special class of regulatory elements known as insulators is believed to be involved in the regulation of specific long-range interactions between enhancers and promoters. This review focuses on the insulators of Drosophila and mammals, and it also briefly characterizes the proteins responsible for their functional activity. It was initially believed that the main properties of insulators are blocking of enhancers and the formation of independent transcription domains. We present experimental data proving that the chromatin loops formed by insulators play only an auxiliary role in enhancer blocking. The review also discusses the mechanisms involved in the formation of topologically associating domains and their role in the formation of the chromosomal architecture and regulation of gene transcription.
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Affiliation(s)
- L. S. Melnikova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334 Russia
| | - P. G. Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334 Russia
| | - A. K. Golovnin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334 Russia
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14
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Fursova NA, Mazina MY, Nikolenko JV, Vorobyova NE, Krasnov AN. Drosophila Zinc Finger Protein CG9890 Is Colocalized with Chromatin Modifying and Remodeling Complexes on Gene Promoters and Involved in Transcription Regulation. Acta Naturae 2020; 12:114-119. [PMID: 33456983 PMCID: PMC7800599 DOI: 10.32607/actanaturae.11056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this work, we conducted a genome-wide study of the zinc finger protein
CG9890 and showed that it is localized mostly on the promoters of active genes.
The CG9890 binding sites are low-nucleosome-density regions and are colocalized
with the chromatin modifying and remodeling complexes SAGA and dSWI/SNF, as
well as with the ORC replication complex. The CG9890 protein was shown to be
involved in the regulation of the expression of some genes on the promoters of
which it is located, with the ecdysone cascade genes accounting for a
significant percentage of these genes. Thus, the CG9890 protein is a new member
of the transcriptional network which is localized on active promoters,
interacts with the main transcription and replication complexes, and is
involved in the regulation of both basal and inducible transcription.
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Affiliation(s)
- N. A. Fursova
- Institute of Gene Biology Russian Academy of Sciences, Moscow, 119334 Russia
| | - M. Y. Mazina
- Institute of Gene Biology Russian Academy of Sciences, Moscow, 119334 Russia
| | - J. V. Nikolenko
- Institute of Gene Biology Russian Academy of Sciences, Moscow, 119334 Russia
| | - N. E. Vorobyova
- Institute of Gene Biology Russian Academy of Sciences, Moscow, 119334 Russia
| | - A. N. Krasnov
- Institute of Gene Biology Russian Academy of Sciences, Moscow, 119334 Russia
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15
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Nuño-Cabanes C, Rodríguez-Navarro S. The promiscuity of the SAGA complex subunits: Multifunctional or moonlighting proteins? BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194607. [PMID: 32712338 DOI: 10.1016/j.bbagrm.2020.194607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 12/15/2022]
Abstract
Gene expression, the decoding of DNA information into accessible instructions for protein synthesis, is a complex process in which multiple steps, including transcription, mRNA processing and mRNA export, are regulated by different factors. One of the first steps in this process involves chemical and structural changes in chromatin to allow transcription. For such changes to occur, histone tail and DNA epigenetic modifications foster the binding of transcription factors to promoter regions. The SAGA coactivator complex plays a crucial role in this process by mediating histone acetylation through Gcn5, and histone deubiquitination through Ubp8 enzymes. However, most SAGA subunits interact physically with other proteins beyond the SAGA complex. These interactions could represent SAGA-independent functions or a mechanism to widen SAGA multifunctionality. Among the different mechanisms to perform more than one function, protein moonlighting defines unrelated molecular activities for the same polypeptide sequence. Unlike pleiotropy, where a single gene can affect different phenotypes, moonlighting necessarily involves separate functions of a protein at the molecular level. In this review we describe in detail some of the alternative physical interactions of several SAGA subunits. In some cases, the alternative role constitutes a clear moonlighting function, whereas in most of them the lack of molecular evidence means that we can only define these interactions as promiscuous that require further work to verify if these are moonlighting functions.
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Affiliation(s)
- Carme Nuño-Cabanes
- Gene Expression and RNA Metabolism Laboratory, Instituto de Biomedicina de Valencia (CSIC), Jaume Roig, 11, E-46010 Valencia, Spain
| | - Susana Rodríguez-Navarro
- Gene Expression and RNA Metabolism Laboratory, Instituto de Biomedicina de Valencia (CSIC), Jaume Roig, 11, E-46010 Valencia, Spain.
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16
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Wang XK, Wang QQ, Huang JL, Zhang LB, Zhou X, Liu JQ, Chen ZJ, Liao XW, Huang R, Yang CK, Zhu GZ, Han CY, Ye XP, Peng T. Novel candidate biomarkers of origin recognition complex 1, 5 and 6 for survival surveillance in patients with hepatocellular carcinoma. J Cancer 2020; 11:1869-1882. [PMID: 32194798 PMCID: PMC7052853 DOI: 10.7150/jca.39163] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 12/20/2019] [Indexed: 01/02/2023] Open
Abstract
Background: Hepatocellular carcinoma (HCC) has high morbidity and mortality and lacks effective biomarkers for early diagnosis and survival surveillance. Origin recognition complex (ORC), consisting of ORC1-6 isoforms, was examined to assess the potential significance of ORC isoforms for HCC prognosis. Methods: Oncomine and Gene Expression Profiling Interactive Analysis (GEPIA) databases were used to examine differential isoform expression, stage-specific expression, calculate Pearson correlations and perform survival analysis. A human protein atlas database was utilized to evaluate the protein expression of ORCs in liver tissue. The cBioPortal database was used to assess isoform mutations and the survival significance of ORCs in HCC. Cytoscape software was employed to construct gene ontologies, metabolic pathways and gene-gene interaction networks. Results: Differential expression analysis indicated that ORC1 and ORC3-6 were highly expressed in tumor tissues in the Oncomine and GEPIA databases, while ORC2 was not. All the ORCs were showed positive and statistically significant correlations with each other (all P<0.001). ORC1-2 and ORC4-6 expressions were associated with disease stages I-IV (all P<0.05), but ORC3 was not. Survival analysis found that ORC1 and ORC4-6 expressions were associated with overall survival (OS), and ORC1-3 and ORC5-6 expression were associated with recurrence-free survival (RFS; all P<0.05). In addition, low expression of these ORC genes consistently indicated better prognosis compared with high expression. Protein expression analysis revealed that ORC1 and ORC3-6 were expressed in normal liver tissues, whereas ORC2 was not. Enrichment analysis indicated that ORCs were associated with DNA metabolic process, sequence-specific DNA binding and were involved in DNA replication, cell cycle, E2F-enabled inhibition of pre-replication complex formation and G1/S transition. Conclusions: Differentially expressed ORC1, 5 and 6 are candidate biomarkers for survival prediction and recurrence surveillance in HCC.
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Affiliation(s)
- Xiang-Kun Wang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Qiao-Qi Wang
- Department of Medical Cosmetology, The Second Affiliated Hospital of Guangxi Medical University, Nanning 530000, Guangxi Province, China
| | - Jian-Lu Huang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
- Department of Hepatobiliary Surgery, The Third Affiliated Hospital of Guangxi Medical University, Nanning 530031, Guangxi Province, China
| | - Lin-Bo Zhang
- Department of Health Management and Division of Physical Examination, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Zhuang Autonomous Region, People's Republic of China
| | - Xin Zhou
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Jun-Qi Liu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Zi-Jun Chen
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Xi-Wen Liao
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Rui Huang
- Department of Hematology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Cheng-Kun Yang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Guang-Zhi Zhu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Chuang-Ye Han
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Xin-Ping Ye
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
| | - Tao Peng
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi Province, China
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17
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The same domain of Su(Hw) is required for enhancer blocking and direct promoter repression. Sci Rep 2019; 9:5314. [PMID: 30926937 PMCID: PMC6441048 DOI: 10.1038/s41598-019-41761-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 03/14/2019] [Indexed: 12/22/2022] Open
Abstract
Suppressor of Hairy-wing [Su(Hw)] is a DNA-binding architectural protein that participates in the organization of insulators and repression of promoters in Drosophila. This protein contains acidic regions at both ends and a central cluster of 12 zinc finger domains, some of which are involved in the specific recognition of the binding site. One of the well-described in vivo function of Su(Hw) is the repression of transcription of neuronal genes in oocytes. Here, we have found that the same Su(Hw) C-terminal region (aa 720–892) is required for insulation as well as for promoter repression. The best characterized partners of Su(Hw), CP190 and Mod(mdg4)-67.2, are not involved in the repression of neuronal genes. Taken together, these results suggest that an unknown protein or protein complex binds to the C-terminal region of Su(Hw) and is responsible for the direct repression activity of Su(Hw).
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18
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Glenn SE, Geyer PK. Investigation of the Developmental Requirements of Drosophila HP1 and Insulator Protein Partner, HIPP1. G3 (BETHESDA, MD.) 2019; 9:345-357. [PMID: 30514714 PMCID: PMC6385973 DOI: 10.1534/g3.118.200705] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/30/2018] [Indexed: 12/02/2022]
Abstract
Drosophila Suppressor of Hairy-wing [Su(Hw)] is a multifunctional zinc finger DNA binding protein. Transcriptional regulation by Su(Hw) is essential in the ovary and testis, where Su(Hw) functions primarily as a repressor. Recently, the HP1a and Insulator Partner Protein 1 (HIPP1) was found to extensively co-localize with Su(Hw) and other insulator binding proteins in euchromatic regions of the genome, and with Heterochromatin Protein 1a (HP1a) in heterochromatic regions. As HIPP1 is the homolog of the human co-repressor Chromodomain Y-Like (CDYL), we tested its requirement in establishing transcriptional repression in flies. To this end, we generated multiple Hipp1 null alleles and a tagged derivative of the endogenous gene (Hipp1GFP ), using CRISPR mutagenesis. We show that HIPP1 is a widely expressed nuclear protein that is dispensable for viability, as well as female and male fertility. We find that HIPP1 and HP1a display minimum co-localization in interphase cells, and HP1a-dependent transcriptional repression of several reporter genes is HIPP1-independent, indicating that HIPP1 is not essential for HP1a-dependent heterochromatin formation. Despite Su(Hw) having a major role in promoting HIPP1 occupancy in euchromatin, we show that HIPP1 is dispensable for the transcriptional and insulator functions of Su(Hw), indicating that HIPP1 is not a critical Su(Hw) cofactor. Further studies are needed to clarify the role of HIPP1 in Drosophila development.
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Affiliation(s)
| | - Pamela K Geyer
- Molecular Medicine Program
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242
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19
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Melnikova L, Kostyuchenko M, Molodina V, Parshikov A, Georgiev P, Golovnin A. Multiple interactions are involved in a highly specific association of the Mod(mdg4)-67.2 isoform with the Su(Hw) sites in Drosophila. Open Biol 2018; 7:rsob.170150. [PMID: 29021216 PMCID: PMC5666082 DOI: 10.1098/rsob.170150] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 09/18/2017] [Indexed: 12/13/2022] Open
Abstract
The best-studied Drosophila insulator complex consists of two BTB-containing proteins, the Mod(mdg4)-67.2 isoform and CP190, which are recruited to the chromatin through interactions with the DNA-binding Su(Hw) protein. It was shown previously that Mod(mdg4)-67.2 is critical for the enhancer-blocking activity of the Su(Hw) insulators and it differs from more than 30 other Mod(mdg4) isoforms by the C-terminal domain required for a specific interaction with Su(Hw) only. The mechanism of the highly specific association between Mod(mdg4)-67.2 and Su(Hw) is not well understood. Therefore, we have performed a detailed analysis of domains involved in the interaction of Mod(mdg4)-67.2 with Su(Hw) and CP190. We found that the N-terminal region of Su(Hw) interacts with the glutamine-rich domain common to all the Mod(mdg4) isoforms. The unique C-terminal part of Mod(mdg4)-67.2 contains the Su(Hw)-interacting domain and the FLYWCH domain that facilitates a specific association between Mod(mdg4)-67.2 and the CP190/Su(Hw) complex. Finally, interaction between the BTB domain of Mod(mdg4)-67.2 and the M domain of CP190 has been demonstrated. By using transgenic lines expressing different protein variants, we have shown that all the newly identified interactions are to a greater or lesser extent redundant, which increases the reliability in the formation of the protein complexes.
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Affiliation(s)
- Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| | - Margarita Kostyuchenko
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| | - Varvara Molodina
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| | - Alexander Parshikov
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| | - Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
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20
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Maksimenko OG, Belova EV, Georgiev PG. Identification of the ORC Complex Subunits That Can Interact with the ENY2 Protein of Drosophila melanogaster. DOKL BIOCHEM BIOPHYS 2018; 480:155-157. [PMID: 30008099 DOI: 10.1134/s1607672918030080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Indexed: 11/23/2022]
Abstract
The interaction of the Drosophila ENY2 protein with the ORC complex subunits was investigated. It is found that ORC4 and ORC6 subunits directly interact with ENY2.
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Affiliation(s)
- O G Maksimenko
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
| | - E V Belova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - P G Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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21
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Melnikova L, Kostyuchenko M, Parshikov A, Georgiev P, Golovnin A. Role of Su(Hw) zinc finger 10 and interaction with CP190 and Mod(mdg4) proteins in recruiting the Su(Hw) complex to chromatin sites in Drosophila. PLoS One 2018; 13:e0193497. [PMID: 29474480 PMCID: PMC5825117 DOI: 10.1371/journal.pone.0193497] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 02/12/2018] [Indexed: 02/07/2023] Open
Abstract
Su(Hw) belongs to the class of proteins that organize chromosome architecture and boundaries/insulators between regulatory domains. This protein contains a cluster of 12 zinc finger domains most of which are responsible for binding to three different modules in the consensus site. Su(Hw) forms a complex with CP190 and Mod(mdg4)-67.2 proteins that binds to well-known Drosophila insulators. To understand how Su(Hw) performs its activities and binds to specific sites in chromatin, we have examined the previously described su(Hw)f mutation that disrupts the 10th zinc finger (ZF10) responsible for Su(Hw) binding to the upstream module. The results have shown that Su(Hw)f loses the ability to interact with CP190 in the absence of DNA. In contrast, complete deletion of ZF10 does not prevent the interaction between Su(Hw)Δ10 and CP190. Having studied insulator complex formation in different mutant backgrounds, we conclude that both association with CP190 and Mod(mdg4)-67.2 partners and proper organization of DNA binding site are essential for the efficient recruitment of the Su(Hw) complex to chromatin insulators.
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Affiliation(s)
- Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Margarita Kostyuchenko
- Department of Drosophila Molecular Genetics, 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
- * E-mail: (AG); (PG)
| | - Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- * E-mail: (AG); (PG)
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22
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Zolotarev N, Maksimenko O, Kyrchanova O, Sokolinskaya E, Osadchiy I, Girardot C, Bonchuk A, Ciglar L, Furlong EEM, Georgiev P. Opbp is a new architectural/insulator protein required for ribosomal gene expression. Nucleic Acids Res 2017; 45:12285-12300. [PMID: 29036346 PMCID: PMC5716193 DOI: 10.1093/nar/gkx840] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/14/2017] [Indexed: 12/22/2022] Open
Abstract
A special class of poorly characterized architectural proteins is required for chromatin topology and enhancer–promoter interactions. Here, we identify Opbp as a new Drosophila architectural protein, interacting with CP190 both in vivo and in vitro. Opbp binds to a very restrictive set of genomic regions, through a rare sequence specific motif. These sites are co-bound by CP190 in vivo, and generally located at bidirectional promoters of ribosomal protein genes. We show that Opbp is essential for viability, and loss of opbp function, or destruction of its motif, leads to reduced ribosomal protein gene expression, indicating a functional role in promoter activation. As characteristic of architectural/insulator proteins, the Opbp motif is sufficient for distance-dependent reporter gene activation and enhancer-blocking activity, suggesting an Opbp-mediated enhancer–promoter interaction. Rather than having a constitutive role, Opbp represents a new type of architectural protein with a very restricted, yet essential, function in regulation of housekeeping gene expression.
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Affiliation(s)
- Nikolay Zolotarev
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Oksana Maksimenko
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Olga Kyrchanova
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Elena Sokolinskaya
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia.,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119234, Russia
| | - Igor Osadchiy
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Charles Girardot
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Artem Bonchuk
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Lucia Ciglar
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Eileen E M Furlong
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Pavel Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
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23
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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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24
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Ali T, Krüger M, Bhuju S, Jarek M, Bartkuhn M, Renkawitz R. Chromatin binding of Gcn5 in Drosophila is largely mediated by CP190. Nucleic Acids Res 2017; 45:2384-2395. [PMID: 27903907 PMCID: PMC5389606 DOI: 10.1093/nar/gkw1178] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 11/17/2016] [Indexed: 12/18/2022] Open
Abstract
Centrosomal 190 kDa protein (CP190) is a promoter binding factor, mediates long-range interactions in the context of enhancer-promoter contacts and in chromosomal domain formation. All Drosophila insulator proteins bind CP190 suggesting a crucial role in insulator function. CP190 has major effects on chromatin, such as depletion of nucleosomes, high nucleosomal turnover and prevention of heterochromatin expansion. Here, we searched for enzymes, which might be involved in CP190 mediated chromatin changes. Eighty percent of the genomic binding sites of the histone acetyltransferase Gcn5 are colocalizing with CP190 binding. Depletion of CP190 reduces Gcn5 binding to chromatin. Binding dependency was further supported by Gcn5 mediated co-precipitation of CP190. Gcn5 is known to activate transcription by histone acetylation. We used the dCas9 system to target CP190 or Gcn5 to a Polycomb repressed and H3K27me3 marked gene locus. Both, CP190 as well as Gcn5, activate this locus, thus supporting the model that CP190 recruits Gcn5 and thereby activates chromatin.
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Affiliation(s)
- Tamer Ali
- Institute for Genetics, Justus-Liebig-University, D35392 Giessen, Germany
| | - Marcus Krüger
- CECAD Research Center, University of Cologne, D50931 Cologne, Germany
| | - Sabin Bhuju
- Helmholtz Centre for Infection Research, D38124 Braunschweig, Germany
| | - Michael Jarek
- Helmholtz Centre for Infection Research, D38124 Braunschweig, Germany
| | - Marek Bartkuhn
- Institute for Genetics, Justus-Liebig-University, D35392 Giessen, Germany
| | - Rainer Renkawitz
- Institute for Genetics, Justus-Liebig-University, D35392 Giessen, Germany
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25
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Different Evolutionary Strategies To Conserve Chromatin Boundary Function in the Bithorax Complex. Genetics 2016; 205:589-603. [PMID: 28007886 PMCID: PMC5289839 DOI: 10.1534/genetics.116.195586] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/12/2016] [Indexed: 12/01/2022] Open
Abstract
Chromatin boundary elements subdivide chromosomes in multicellular organisms into physically independent domains. In addition to this architectural function, these elements also play a critical role in gene regulation. Here we investigated the evolution of a Drosophila Bithorax complex boundary element called Fab-7, which is required for the proper parasegment specific expression of the homeotic Abd-B gene. Using a “gene” replacement strategy, we show that Fab-7 boundaries from two closely related species, D. erecta and D. yakuba, and a more distant species, D. pseudoobscura, are able to substitute for the melanogaster boundary. Consistent with this functional conservation, the two known Fab-7 boundary factors, Elba and LBC, have recognition sequences in the boundaries from all species. However, the strategies used for maintaining binding and function in the face of sequence divergence is different. The first is conventional, and depends upon conservation of the 8 bp Elba recognition sequence. The second is unconventional, and takes advantage of the unusually large and flexible sequence recognition properties of the LBC boundary factor, and the deployment of multiple LBC recognition elements in each boundary. In the former case, binding is lost when the recognition sequence is altered. In the latter case, sequence divergence is accompanied by changes in the number, relative affinity, and location of the LBC recognition elements.
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26
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Bonchuk AN, Georgiev PG, Maksimenko OG. CTCF and Sgfl1 proteins form alternative complexes with ENY2 proteins. DOKL BIOCHEM BIOPHYS 2016; 468:180-2. [DOI: 10.1134/s1607672916030054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Indexed: 11/23/2022]
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27
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Melnikova L, Shapovalov I, Kostyuchenko M, Georgiev P, Golovnin A. EAST affects the activity of Su(Hw) insulators by two different mechanisms in Drosophila melanogaster. Chromosoma 2016; 126:299-311. [PMID: 27136940 DOI: 10.1007/s00412-016-0596-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/24/2016] [Accepted: 04/21/2016] [Indexed: 10/21/2022]
Abstract
Recent data suggest that insulators organize chromatin architecture in the nucleus. The best characterized Drosophila insulator, found in the gypsy retrotransposon, contains 12 binding sites for the Su(Hw) protein. Enhancer blocking, along with Su(Hw), requires BTB/POZ domain proteins, Mod(mdg4)-67.2 and CP190. Inactivation of Mod(mdg4)-67.2 leads to a direct repression of the yellow gene promoter by the gypsy insulator. Here, we have shown that such repression is regulated by the level of the EAST protein, which is an essential component of the interchromatin compartment. Deletion of the EAST C-terminal domain suppresses Su(Hw)-mediated repression. Partial inactivation of EAST by mutations in the east gene suppresses the enhancer-blocking activity of the gypsy insulator. The binding of insulator proteins to chromatin is highly sensitive to the level of EAST expression. These results suggest that EAST, one of the main components of the interchromatin compartment, can regulate the activity of chromatin insulators.
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Affiliation(s)
- Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Igor Shapovalov
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Margarita Kostyuchenko
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia.
| | - Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia.
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AbuQattam A, Gallego J, Rodríguez-Navarro S. An intronic RNA structure modulates expression of the mRNA biogenesis factor Sus1. RNA (NEW YORK, N.Y.) 2016; 22:75-86. [PMID: 26546116 PMCID: PMC4691836 DOI: 10.1261/rna.054049.115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/03/2015] [Indexed: 06/05/2023]
Abstract
Sus1 is a conserved protein involved in chromatin remodeling and mRNA biogenesis. Unlike most yeast genes, the SUS1 pre-mRNA of Saccharomyces cerevisiae contains two introns and is alternatively spliced, retaining one or both introns in response to changes in environmental conditions. SUS1 splicing may allow the cell to control Sus1 expression, but the mechanisms that regulate this process remain unknown. Using in silico analyses together with NMR spectroscopy, gel electrophoresis, and UV thermal denaturation experiments, we show that the downstream intron (I2) of SUS1 forms a weakly stable, 37-nucleotide stem-loop structure containing the branch site near its apical loop and the 3' splice site after the stem terminus. A cellular assay revealed that two of four mutants containing altered I2 structures had significantly impaired SUS1 expression. Semiquantitative RT-PCR experiments indicated that all mutants accumulated unspliced SUS1 pre-mRNA and/or induced distorted levels of fully spliced mRNA relative to wild type. Concomitantly, Sus1 cellular functions in histone H2B deubiquitination and mRNA export were affected in I2 hairpin mutants that inhibited splicing. This work demonstrates that I2 structure is relevant for SUS1 expression, and that this effect is likely exerted through modulation of splicing.
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Affiliation(s)
- Ali AbuQattam
- Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe, Valencia 46012, Spain Facultad de Medicina, Universidad Católica de Valencia, Valencia 46001, Spain
| | - José Gallego
- Facultad de Medicina, Universidad Católica de Valencia, Valencia 46001, Spain
| | - Susana Rodríguez-Navarro
- Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe, Valencia 46012, Spain
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Golovnin A, Melnikova L, Shapovalov I, Kostyuchenko M, Georgiev P. EAST Organizes Drosophila Insulator Proteins in the Interchromosomal Nuclear Compartment and Modulates CP190 Binding to Chromatin. PLoS One 2015; 10:e0140991. [PMID: 26489095 PMCID: PMC4638101 DOI: 10.1371/journal.pone.0140991] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 10/02/2015] [Indexed: 12/02/2022] Open
Abstract
Recent data suggest that insulators organize chromatin architecture in the nucleus. The best studied Drosophila insulator proteins, dCTCF (a homolog of the vertebrate insulator protein CTCF) and Su(Hw), are DNA-binding zinc finger proteins. Different isoforms of the BTB-containing protein Mod(mdg4) interact with Su(Hw) and dCTCF. The CP190 protein is a cofactor for the dCTCF and Su(Hw) insulators. CP190 is required for the functional activity of insulator proteins and is involved in the aggregation of the insulator proteins into specific structures named nuclear speckles. Here, we have shown that the nuclear distribution of CP190 is dependent on the level of EAST protein, an essential component of the interchromatin compartment. EAST interacts with CP190 and Mod(mdg4)-67.2 proteins in vitro and in vivo. Over-expression of EAST in S2 cells leads to an extrusion of the CP190 from the insulator bodies containing Su(Hw), Mod(mdg4)-67.2, and dCTCF. In consistent with the role of the insulator bodies in assembly of protein complexes, EAST over-expression led to a striking decrease of the CP190 binding with the dCTCF and Su(Hw) dependent insulators and promoters. These results suggest that EAST is involved in the regulation of CP190 nuclear localization.
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Affiliation(s)
- Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Igor Shapovalov
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Margarita Kostyuchenko
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
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Functional Requirements for Fab-7 Boundary Activity in the Bithorax Complex. Mol Cell Biol 2015; 35:3739-52. [PMID: 26303531 DOI: 10.1128/mcb.00456-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/17/2015] [Indexed: 12/23/2022] Open
Abstract
Chromatin boundaries are architectural elements that determine the three-dimensional folding of the chromatin fiber and organize the chromosome into independent units of genetic activity. The Fab-7 boundary from the Drosophila bithorax complex (BX-C) is required for the parasegment-specific expression of the Abd-B gene. We have used a replacement strategy to identify sequences that are necessary and sufficient for Fab-7 boundary function in the BX-C. Fab-7 boundary activity is known to depend on factors that are stage specific, and we describe a novel ∼700-kDa complex, the late boundary complex (LBC), that binds to Fab-7 sequences that have insulator functions in late embryos and adults. We show that the LBC is enriched in nuclear extracts from late, but not early, embryos and that it contains three insulator proteins, GAF, Mod(mdg4), and E(y)2. Its DNA binding properties are unusual in that it requires a minimal sequence of >65 bp; however, other than a GAGA motif, the three Fab-7 LBC recognition elements display few sequence similarities. Finally, we show that mutations which abrogate LBC binding in vitro inactivate the Fab-7 boundary in the BX-C.
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31
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Schoborg T, Labrador M. Expanding the roles of chromatin insulators in nuclear architecture, chromatin organization and genome function. Cell Mol Life Sci 2014; 71:4089-113. [PMID: 25012699 PMCID: PMC11113341 DOI: 10.1007/s00018-014-1672-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/31/2014] [Accepted: 06/23/2014] [Indexed: 01/08/2023]
Abstract
Of the numerous classes of elements involved in modulating eukaryotic chromosome structure and function, chromatin insulators arguably remain the most poorly understood in their contribution to these processes in vivo. Indeed, our view of chromatin insulators has evolved dramatically since their chromatin boundary and enhancer blocking properties were elucidated roughly a quarter of a century ago as a result of recent genome-wide, high-throughput methods better suited to probing the role of these elements in their native genomic contexts. The overall theme that has emerged from these studies is that chromatin insulators function as general facilitators of higher-order chromatin loop structures that exert both physical and functional constraints on the genome. In this review, we summarize the result of recent work that supports this idea as well as a number of other studies linking these elements to a diverse array of nuclear processes, suggesting that chromatin insulators exert master control over genome organization and behavior.
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Affiliation(s)
- Todd Schoborg
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
- Present Address: Laboratory of Molecular Machines and Tissue Architecture, Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 50 South Dr Rm 2122, Bethesda, MD 20892 USA
| | - Mariano Labrador
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
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32
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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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33
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Durairaj G, Sen R, Uprety B, Shukla A, Bhaumik SR. Sus1p facilitates pre-initiation complex formation at the SAGA-regulated genes independently of histone H2B de-ubiquitylation. J Mol Biol 2014; 426:2928-2941. [PMID: 24911582 DOI: 10.1016/j.jmb.2014.05.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/29/2014] [Accepted: 05/31/2014] [Indexed: 12/23/2022]
Abstract
Sus1p is a common component of transcriptional co-activator, SAGA (Spt-Ada-Gcn5-Acetyltransferase), and mRNA export complex, TREX-2 (Transcription-export 2), and is involved in promoting transcription and mRNA export. However, it is not clearly understood how Sus1p promotes transcription. Here, we show that Sus1p is predominantly recruited to the upstream activating sequence of a SAGA-dependent gene, GAL1, under transcriptionally active conditions as a component of SAGA to promote the formation of pre-initiation complex (PIC) at the core promoter and, consequently, transcriptional initiation. Likewise, Sus1p promotes the PIC formation at other SAGA-dependent genes and hence transcriptional initiation. Such function of Sus1p in promoting PIC formation and transcriptional initiation is not mediated via its role in regulation of SAGA's histone H2B de-ubiquitylation activity. However, Sus1p's function in regulation of histone H2B ubiquitylation is associated with transcriptional elongation, DNA repair and replication. Collectively, our results support that Sus1p promotes PIC formation (and hence transcriptional initiation) at the SAGA-regulated genes independently of histone H2B de-ubiquitylation and further controls transcriptional elongation, DNA repair and replication via orchestration of histone H2B ubiquitylation, thus providing distinct functional insights of Sus1p in regulation of DNA transacting processes.
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Affiliation(s)
- Geetha Durairaj
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Rwik Sen
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Bhawana Uprety
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Abhijit Shukla
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
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Stancheva I, Schirmer EC. Nuclear Envelope: Connecting Structural Genome Organization to Regulation of Gene Expression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 773:209-44. [DOI: 10.1007/978-1-4899-8032-8_10] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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35
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Gurskiy DY, Nabirochkina EN, Kopytova DV. Role of multifunctional coactivator complex SAGA in regulation of eukaryotic gene expression. Mol Biol 2013. [DOI: 10.1134/s002689331306006x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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36
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Chetverina D, Aoki T, Erokhin M, Georgiev P, Schedl P. Making connections: insulators organize eukaryotic chromosomes into independent cis-regulatory networks. Bioessays 2013; 36:163-72. [PMID: 24277632 DOI: 10.1002/bies.201300125] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Insulators play a central role in subdividing the chromosome into a series of discrete topologically independent domains and in ensuring that enhancers and silencers contact their appropriate target genes. In this review we first discuss the general characteristics of insulator elements and their associated protein factors. A growing collection of insulator proteins have been identified including a family of proteins whose expression is developmentally regulated. We next consider several unexpected discoveries that require us to completely rethink how insulators function (and how they can best be assayed). These discoveries also require a reevaluation of how insulators might restrict or orchestrate (by preventing or promoting) interactions between regulatory elements and their target genes. We conclude by connecting these new insights into the mechanisms of insulator action to dynamic changes in the three-dimensional topology of the chromatin fiber and the generation of specific patterns of gene activity during development and differentiation.
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Affiliation(s)
- Darya Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
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Matzat LH, Lei EP. Surviving an identity crisis: a revised view of chromatin insulators in the genomics era. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1839:203-14. [PMID: 24189492 DOI: 10.1016/j.bbagrm.2013.10.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022]
Abstract
The control of complex, developmentally regulated loci and partitioning of the genome into active and silent domains is in part accomplished through the activity of DNA-protein complexes termed chromatin insulators. Together, the multiple, well-studied classes of insulators in Drosophila melanogaster appear to be generally functionally conserved. In this review, we discuss recent genomic-scale experiments and attempt to reconcile these newer findings in the context of previously defined insulator characteristics based on classical genetic analyses and transgenic approaches. Finally, we discuss the emerging understanding of mechanisms of chromatin insulator regulation. This article is part of a Special Issue entitled: Chromatin and epigenetic regulation of animal development.
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Affiliation(s)
- Leah H Matzat
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elissa P Lei
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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38
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Soshnev AA, Baxley RM, Manak JR, Tan K, Geyer PK. The insulator protein Suppressor of Hairy-wing is an essential transcriptional repressor in the Drosophila ovary. Development 2013; 140:3613-23. [PMID: 23884443 DOI: 10.1242/dev.094953] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Suppressor of Hairy-wing [Su(Hw)] is a DNA-binding factor required for gypsy insulator function and female germline development in Drosophila. The insulator function of the gypsy retrotransposon depends on Su(Hw) binding to clustered Su(Hw) binding sites (SBSs) and recruitment of the insulator proteins Centrosomal Protein 190 kD (CP190) and Modifier of mdg4 67.2 kD (Mod67.2). By contrast, the Su(Hw) germline function involves binding to non-clustered SBSs and does not require CP190 or Mod67.2. Here, we identify Su(Hw) target genes, using genome-wide analyses in the ovary to uncover genes with an ovary-bound SBS that are misregulated upon Su(Hw) loss. Most Su(Hw) target genes demonstrate enriched expression in the wild-type CNS. Loss of Su(Hw) leads to increased expression of these CNS-enriched target genes in the ovary and other tissues, suggesting that Su(Hw) is a repressor of neural genes in non-neural tissues. Among the Su(Hw) target genes is RNA-binding protein 9 (Rbp9), a member of the ELAV/Hu gene family. Su(Hw) regulation of Rbp9 appears to be insulator independent, as Rbp9 expression is unchanged in a genetic background that compromises the functions of the CP190 and Mod67.2 insulator proteins, even though both localize to Rbp9 SBSs. Rbp9 misregulation is central to su(Hw)(-/-) sterility, as Rbp9(+/-), su(Hw)(-/-) females are fertile. Eggs produced by Rbp9(+/-), su(Hw)(-/-) females show patterning defects, revealing a somatic requirement for Su(Hw) in the ovary. Our studies demonstrate that Su(Hw) is a versatile transcriptional regulatory protein with an essential developmental function involving transcriptional repression.
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Affiliation(s)
- Alexey A Soshnev
- Interdisciplinary Graduate Program in Molecular and Cellular Biology, University of Iowa, Iowa City, IA 52242, USA
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Effective blocking of the white enhancer requires cooperation between two main mechanisms suggested for the insulator function. PLoS Genet 2013; 9:e1003606. [PMID: 23861668 PMCID: PMC3701704 DOI: 10.1371/journal.pgen.1003606] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 05/20/2013] [Indexed: 11/24/2022] Open
Abstract
Chromatin insulators block the action of transcriptional enhancers when interposed between an enhancer and a promoter. In this study, we examined the role of chromatin loops formed by two unrelated insulators, gypsy and Fab-7, in their enhancer-blocking activity. To test for this activity, we selected the white reporter gene that is activated by the eye-specific enhancer. The results showed that one copy of the gypsy or Fab-7 insulator failed to block the eye enhancer in most of genomic sites, whereas a chromatin loop formed by two gypsy insulators flanking either the eye enhancer or the reporter completely blocked white stimulation by the enhancer. However, strong enhancer blocking was achieved due not only to chromatin loop formation but also to the direct interaction of the gypsy insulator with the eye enhancer, which was confirmed by the 3C assay. In particular, it was observed that Mod(mdg4)-67.2, a component of the gypsy insulator, interacted with the Zeste protein, which is critical for the eye enhancer–white promoter communication. These results suggest that efficient enhancer blocking depends on the combination of two factors: chromatin loop formation by paired insulators, which generates physical constraints for enhancer–promoter communication, and the direct interaction of proteins recruited to an insulator and to the enhancer–promoter pair. The mechanism underlying enhancer blocking by insulators is unclear. Current models suggest that insulator proteins block enhancers either by formation of chromatin loops or by direct interaction with protein complexes bound to the enhancers and promoters. Here, we tested the role of a chromatin loop in blocking the activity of two Drosophila insulators, gypsy and Fab-7. Both insulators failed to effectively block the interaction between the eye enhancer and the white promoter at most of genomic sites. Insertion of an additional gypsy copy either upstream of the eye enhancer or downstream from the white gene led to complete blocking of the enhancer–promoter communication. In contrast, flanking of the eye enhancer by Fab-7 insulators only weakly improved enhancer blocking. Such a difference in enhancer blocking may be explained by finding that Mod(mdg4)-67.2, a component of gypsy insulator, directly interacts with the Zeste protein, which is critical for enhancer–promoter communication in the white gene.
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40
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Vorobyeva NE, Mazina MU, Golovnin AK, Kopytova DV, Gurskiy DY, Nabirochkina EN, Georgieva SG, Georgiev PG, Krasnov AN. Insulator protein Su(Hw) recruits SAGA and Brahma complexes and constitutes part of Origin Recognition Complex-binding sites in the Drosophila genome. Nucleic Acids Res 2013; 41:5717-30. [PMID: 23609538 PMCID: PMC3675495 DOI: 10.1093/nar/gkt297] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Despite increasing data on the properties of replication origins, molecular mechanisms underlying origin recognition complex (ORC) positioning in the genome are still poorly understood. The Su(Hw) protein accounts for the activity of best-studied Drosophila insulators. Here, we show that Su(Hw) recruits the histone acetyltransferase complex SAGA and chromatin remodeler Brahma to Su(Hw)-dependent insulators, which gives rise to regions with low nucleosome density and creates conditions for ORC binding. Depletion in Su(Hw) leads to a dramatic drop in the levels of SAGA, Brahma and ORC subunits and a significant increase in nucleosome density on Su(Hw)-dependent insulators, whereas artificial Su(Hw) recruitment itself is sufficient for subsequent SAGA, Brahma and ORC binding. In contrast to the majority of replication origins that associate with promoters of active genes, Su(Hw)-binding sites constitute a small proportion (6%) of ORC-binding sites that are localized preferentially in transcriptionally inactive chromatin regions termed BLACK and BLUE chromatin. We suggest that the key determinants of ORC positioning in the genome are DNA-binding proteins that constitute different DNA regulatory elements, including insulators, promoters and enhancers. Su(Hw) is the first example of such a protein.
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Affiliation(s)
- Nadezhda E Vorobyeva
- Department of Transcriptional Regulation and Chromatin Dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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41
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Galán A, Rodríguez-Navarro S. Sus1/ENY2: a multitasking protein in eukaryotic gene expression. Crit Rev Biochem Mol Biol 2012; 47:556-68. [PMID: 23057668 DOI: 10.3109/10409238.2012.730498] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The purpose of this review is to provide a complete overview on the functions of the transcription/export factor Sus1. Sus1 is a tiny conserved factor in sequence and functions through the eukaryotic kingdom. Although it was discovered recently, research done to address the role of Sus1/ENY2 has provided in deep description of different mechanisms influencing gene expression. Initially found to interact with the transcription and mRNA export machinery in yeast, it is now clear that it has a broad role in mRNA biogenesis. Sus1 is necessary for histone H2B deubiquitination, mRNA export and gene gating. Moreover, interesting observations also suggest a link with the cytoplasmatic mRNP fate. Although the role of Sus1 in human cells is largely unknown, preliminary results suggest interesting links to pathological states that range from rare diseases to diabetes. We will describe what is known about Sus1/ENY2 in yeast and other eukaryotes and discuss some exciting open questions to be solved in the future.
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Affiliation(s)
- Amparo Galán
- Centro de Investigación Príncipe Felipe, CIPF. Gene Expression coupled to RNA Transport Laboratory, Eduardo Primo Yúfera, Valencia, Spain
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42
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Suppression of the nuclear factor Eny2 increases insulin secretion in poorly functioning INS-1E insulinoma cells. EXPERIMENTAL DIABETES RESEARCH 2012; 2012:460869. [PMID: 22649445 PMCID: PMC3357931 DOI: 10.1155/2012/460869] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 02/18/2012] [Accepted: 02/21/2012] [Indexed: 01/01/2023]
Abstract
Eny2, the mammalian ortholog of yeast Sus1 and drosophila E(y)2, is a nuclear factor that participates in several steps of gene transcription and in mRNA export. We had previously found that Eny2 expression changes in mouse pancreatic islets during the metabolic adaptation to pregnancy. We therefore hypothesized that the protein contributes to the regulation of islet endocrine cell function and tested this hypothesis in rat INS-1E insulinoma cells. Overexpression of Eny2 had no effect but siRNA-mediated knockdown of Eny2 resulted in markedly increased glucose and exendin-4-induced insulin secretion from otherwise poorly glucose-responsive INS-1E cells. Insulin content, cellular viability, and the expression levels of several key components of glucose sensing remained unchanged; however glucose-dependent cellular metabolism was higher after Eny2 knockdown. Suppression of Eny2 enhanced the intracellular incretin signal downstream of cAMP. The use of specific cAMP analogues and pathway inhibitors primarily implicated the PKA and to a lesser extent the EPAC pathway. In summary, we identified a potential link between the nuclear protein Eny2 and insulin secretion. Suppression of Eny2 resulted in increased glucose and incretin-induced insulin release from a poorly glucose-responsive INS-1E subline. Whether these findings extend to other experimental conditions or to in vivo physiology needs to be determined in further studies.
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43
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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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Golovnin A, Volkov I, Georgiev P. SUMO conjugation is required for the assembly of Drosophila Su(Hw) and Mod(mdg4) into insulator bodies that facilitate insulator complex formation. J Cell Sci 2012; 125:2064-74. [PMID: 22375064 DOI: 10.1242/jcs.100172] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Chromatin insulators are special regulatory elements involved in modulation of enhancer-promoter interactions. The best studied insulators in Drosophila require Suppressor of Hairy Wing [Su(Hw)], Modifier of mdg4 [Mod(mdg4)] and centrosomal 190 kDa (CP190) proteins to be functional. These insulator proteins are colocalized in nuclear speckles named insulator bodies. Here, we demonstrate that post-translational modification of insulator proteins by small ubiquitin-like modifier (SUMO) and intact CP190 protein is crucial for insulator body formation. Inactivation of SUMO binding sites in Mod(mdg4)-67.2 leads to the inability of the mutant protein and Su(Hw) to be assembled into insulator bodies. In vivo functional tests show that a smaller amount of intact Mod(mdg4)-67.2, compared with the mutant protein, is required to restore the normal activity of the Su(Hw) insulator. However, high expression of mutant Mod(mdg4)-67.2 completely rescues the insulator activity, indicating that sumoylation is not necessary for enhancer blocking. These results suggest that insulator bodies function as a depot of sumoylated proteins that are involved in insulation and can facilitate insulator complex formation, but are nonessential for insulator action.
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Affiliation(s)
- Anton Golovnin
- Department of Molecular Genetics of Drosophila, Russian Academy of Sciences, Moscow 119334, Russia.
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Singer SD, Liu Z, Cox KD. Minimizing the unpredictability of transgene expression in plants: the role of genetic insulators. PLANT CELL REPORTS 2012; 31:13-25. [PMID: 21987122 DOI: 10.1007/s00299-011-1167-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Accepted: 09/27/2011] [Indexed: 05/20/2023]
Abstract
The genetic transformation of plants has become a necessary tool for fundamental plant biology research, as well as the generation of engineered plants exhibiting improved agronomic and industrial traits. However, this technology is significantly hindered by the fact that transgene expression is often highly variable amongst independent transgenic lines. Two of the major contributing factors to this type of inconsistency are inappropriate enhancer-promoter interactions and chromosomal position effects, which frequently result in mis-expression or silencing of the transgene, respectively. Since the precise, often tissue-specific, expression of the transgene(s) of interest is often a necessity for the successful generation of transgenic plants, these undesirable side effects have the potential to pose a major challenge for the genetic engineering of these organisms. In this review, we discuss strategies for improving foreign gene expression in plants via the inclusion of enhancer-blocking insulators, which function to impede enhancer-promoter communication, and barrier insulators, which block the spread of heterochromatin, in transgenic constructs. While a complete understanding of these elements remains elusive, recent studies regarding their use in genetically engineered plants indicate that they hold great promise for the improvement of transgene expression, and thus the future of plant biotechnology.
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Affiliation(s)
- Stacy D Singer
- Department of Plant Pathology and Plant-Microbe Biology, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, USA
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Vorobyeva NE, Nikolenko JV, Krasnov AN, Kuzmina JL, Panov VV, Nabirochkina EN, Georgieva SG, Shidlovskii YV. SAYP interacts with DHR3 nuclear receptor and participates in ecdysone-dependent transcription regulation. RUSS J GENET+ 2012. [DOI: 10.1134/s1022795411120155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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García-Oliver E, García-Molinero V, Rodríguez-Navarro S. mRNA export and gene expression: the SAGA-TREX-2 connection. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:555-65. [PMID: 22178374 DOI: 10.1016/j.bbagrm.2011.11.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 11/29/2011] [Accepted: 11/30/2011] [Indexed: 01/07/2023]
Abstract
In the gene expression field, different steps have been traditionally viewed as discrete and unconnected events. Nowadays, genetic and functional studies support the model of a coupled network of physical and functional connections to carry out mRNA biogenesis. Gene expression is a coordinated process that comprises different linked steps like transcription, RNA processing, export to the cytoplasm, translation and degradation of mRNAs. Its regulation is essential for cellular survival and can occur at many different levels. Transcription is the central function that occurs in the nucleus, and RNAPII plays an essential role in mRNA biogenesis. During transcription, nascent mRNA is associated with the mRNA-binding proteins involved in processing and export of the mRNA particle. Cells have developed a network of multi-protein complexes whose functions regulate the different factors involved both temporally and spatially. This coupling mechanism acts as a quality control to solve some of the organization problems of gene expression in vivo, where all the factors implicated ensure that mRNAs are ready to be exported and translated. In this review, we focus on the functional coupling of gene transcription and mRNA export, and place particular emphasis on the relationship between the NPC-associated complex, TREX2, and the transcription co-activator, SAGA. We have pinpointed the experimental evidence for Sus1's roles in transcription initiation, transcription elongation and mRNA export. In addition, we have reviewed other NPC-related processes such as gene gating to the nuclear envelope, the chromatin structure and the cellular context in which these processes take place. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing.
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Affiliation(s)
- Encar García-Oliver
- Centro de Investigación Príncipe Felipe (CIPF), Gene Expression coupled with RNA Transport Laboratory, Valencia, Spain
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Erokhin M, Davydova A, Kyrchanova O, Parshikov A, Georgiev P, Chetverina D. Insulators form gene loops by interacting with promoters in Drosophila. Development 2011; 138:4097-106. [PMID: 21862564 DOI: 10.1242/dev.062836] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chromatin insulators are regulatory elements involved in the modulation of enhancer-promoter communication. The 1A2 and Wari insulators are located immediately downstream of the Drosophila yellow and white genes, respectively. Using an assay based on the yeast GAL4 activator, we have found that both insulators are able to interact with their target promoters in transgenic lines, forming gene loops. The existence of an insulator-promoter loop is confirmed by the fact that insulator proteins could be detected on the promoter only in the presence of an insulator in the transgene. The upstream promoter regions, which are required for long-distance stimulation by enhancers, are not essential for promoter-insulator interactions. Both insulators support basal activity of the yellow and white promoters in eyes. Thus, the ability of insulators to interact with promoters might play an important role in the regulation of basal gene transcription.
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Affiliation(s)
- Maksim Erokhin
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St, Moscow, 119334 Russia
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Baxley RM, Soshnev AA, Koryakov DE, Zhimulev IF, Geyer PK. The role of the Suppressor of Hairy-wing insulator protein in Drosophila oogenesis. Dev Biol 2011; 356:398-410. [PMID: 21651900 DOI: 10.1016/j.ydbio.2011.05.666] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 05/16/2011] [Accepted: 05/22/2011] [Indexed: 12/21/2022]
Abstract
The Drosophila Suppressor of Hairy wing [Su(Hw)] insulator protein has an essential role in the development of the female germline. Here we investigate the function of Su(Hw) in the ovary. We show that Su(Hw) is universally expressed in somatic cells, while germ cell expression is dynamic. Robust levels accumulate in post-mitotic germ cells, where Su(Hw) localization is limited to chromosomes within nurse cells, the specialized cells that support oocyte growth. Although loss of Su(Hw) causes global defects in nurse cell chromosome structure, we demonstrate that these architectural changes are not responsible for the block in oogenesis. Connections between the fertility and insulator functions of Su(Hw) were investigated through studies of the two gypsy insulator proteins, Modifier of (mdg4)67.2 (Mod67.2) and Centrosomal Protein of 190kDa (CP190). Accumulation of these proteins is distinct from Su(Hw), with Mod67.2 and CP190 showing uniform expression in all cells during early stages of oogenesis that diminishes in later stages. Although Mod67.2 and CP190 extensively co-localize with Su(Hw) on nurse cell chromosomes, neither protein is required for nurse cell chromosome development or oocyte production. These data indicate that while the gypsy insulator function requires both Mod67.2 and CP190, these proteins are not essential for oogenesis. These studies represent the first molecular investigations of Su(Hw) function in the germline, which uncover distinct requirements for Su(Hw) insulator and ovary functions.
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Affiliation(s)
- Ryan M Baxley
- Molecular Biology Program, University of Iowa, College of Medicine, Iowa City, IA 52242, USA
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A barrier-only boundary element delimits the formation of facultative heterochromatin in Drosophila melanogaster and vertebrates. Mol Cell Biol 2011; 31:2729-41. [PMID: 21518956 DOI: 10.1128/mcb.05165-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Formation of facultative heterochromatin at specific genomic loci is fundamentally important in defining cellular properties such as differentiation potential and responsiveness to developmental, physiological, and environmental stimuli. By the nature of their formation, heterochromatin and repressive histone marks propagate until the chain reaction is broken. While certain active promoters can block propagation of heterochromatin, there are also specialized DNA elements, referred to as chromatin barriers, that serve to demarcate the boundary of facultative heterochromatin formation. In this study, we identified a chromatin barrier that specifically limits the formation of repressive chromatin to a distal enhancer region so that repressive histone modifications cannot reach the promoter and promoter-proximal enhancer regions of reaper. Unlike all of the known boundary elements identified for Drosophila melanogaster, this IRER (irradiation-responsive enhancer region) left barrier (ILB) does not exhibit enhancer-blocking activity. Not only has the ILB been conserved in different Drosophila species, it can also function as an effective chromatin barrier in vertebrate cells. This suggests that the mechanism by which it functions to spatially restrict the formation of repressive chromatin marked by trimethylated H3K27 has also been conserved widely during evolution.
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