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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: 0.3] [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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Hsu SJ, Stow EC, Simmons JR, Wallace HA, Lopez AM, Stroud S, Labrador M. Mutations in the insulator protein Suppressor of Hairy wing induce genome instability. Chromosoma 2020; 129:255-274. [PMID: 33140220 DOI: 10.1007/s00412-020-00743-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 12/14/2022]
Abstract
Insulator proteins orchestrate the three-dimensional organization of the genome. Insulators function by facilitating communications between regulatory sequences and gene promoters, allowing accurate gene transcription regulation during embryo development and cell differentiation. However, the role of insulator proteins beyond genome organization and transcription regulation remains unclear. Suppressor of Hairy wing [Su(Hw)] is a Drosophila insulator protein that plays an important function in female oogenesis. Here we find that su(Hw) has an unsuspected role in genome stability during cell differentiation. We show that su(Hw) mutant developing egg chambers have poorly formed microtubule organization centers (MTOCs) in the germarium and display mislocalization of the anterior/posterior axis specification factor gurken in later oogenesis stages. Additionally, eggshells from partially rescued su(Hw) mutant female germline exhibit dorsoventral patterning defects. These phenotypes are very similar to phenotypes found in the important class of spindle mutants or in piRNA pathway mutants in Drosophila, in which defects generally result from the failure of germ cells to repair DNA damage. Similarities between mutations in su(Hw) and spindle and piRNA mutants are further supported by an excess of DNA damage in nurse cells, and because Gurken localization defects are partially rescued by mutations in the ATR (mei-41) and Chk1 (grapes) DNA damage response genes. Finally, we also show that su(Hw) mutants produce an elevated number of chromosome breaks in dividing neuroblasts from larval brains. Together, these findings suggest that Su(Hw) is necessary for the maintenance of genome integrity during Drosophila development, in both germline and dividing somatic cells.
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Affiliation(s)
- Shih-Jui Hsu
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, 37996, USA
| | - 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
| | - Heather A Wallace
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, 37996, USA
| | - Andrea Mancheno Lopez
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, 37996, USA
| | - Shannon Stroud
- 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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3
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Hinnant TD, Merkle JA, Ables ET. Coordinating Proliferation, Polarity, and Cell Fate in the Drosophila Female Germline. Front Cell Dev Biol 2020; 8:19. [PMID: 32117961 PMCID: PMC7010594 DOI: 10.3389/fcell.2020.00019] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 01/10/2020] [Indexed: 01/05/2023] Open
Abstract
Gametes are highly specialized cell types produced by a complex differentiation process. Production of viable oocytes requires a series of precise and coordinated molecular events. Early in their development, germ cells are an interconnected group of mitotically dividing cells. Key regulatory events lead to the specification of mature oocytes and initiate a switch to the meiotic cell cycle program. Though the chromosomal events of meiosis have been extensively studied, it is unclear how other aspects of oocyte specification are temporally coordinated. The fruit fly, Drosophila melanogaster, has long been at the forefront as a model system for genetics and cell biology research. The adult Drosophila ovary continuously produces germ cells throughout the organism’s lifetime, and many of the cellular processes that occur to establish oocyte fate are conserved with mammalian gamete development. Here, we review recent discoveries from Drosophila that advance our understanding of how early germ cells balance mitotic exit with meiotic initiation. We discuss cell cycle control and establishment of cell polarity as major themes in oocyte specification. We also highlight a germline-specific organelle, the fusome, as integral to the coordination of cell division, cell polarity, and cell fate in ovarian germ cells. Finally, we discuss how the molecular controls of the cell cycle might be integrated with cell polarity and cell fate to maintain oocyte production.
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Affiliation(s)
- Taylor D Hinnant
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Julie A Merkle
- Department of Biology, University of Evansville, Evansville, IN, United States
| | - Elizabeth T Ables
- Department of Biology, East Carolina University, Greenville, NC, United States
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5
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Pauli T, Vedder L, Dowling D, Petersen M, Meusemann K, Donath A, Peters RS, Podsiadlowski L, Mayer C, Liu S, Zhou X, Heger P, Wiehe T, Hering L, Mayer G, Misof B, Niehuis O. Transcriptomic data from panarthropods shed new light on the evolution of insulator binding proteins in insects : Insect insulator proteins. BMC Genomics 2016; 17:861. [PMID: 27809783 PMCID: PMC5094011 DOI: 10.1186/s12864-016-3205-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 10/25/2016] [Indexed: 01/19/2023] Open
Abstract
Background Body plan development in multi-cellular organisms is largely determined by homeotic genes. Expression of homeotic genes, in turn, is partially regulated by insulator binding proteins (IBPs). While only a few enhancer blocking IBPs have been identified in vertebrates, the common fruit fly Drosophila melanogaster harbors at least twelve different enhancer blocking IBPs. We screened recently compiled insect transcriptomes from the 1KITE project and genomic and transcriptomic data from public databases, aiming to trace the origin of IBPs in insects and other arthropods. Results Our study shows that the last common ancestor of insects (Hexapoda) already possessed a substantial number of IBPs. Specifically, of the known twelve insect IBPs, at least three (i.e., CP190, Su(Hw), and CTCF) already existed prior to the evolution of insects. Furthermore we found GAF orthologs in early branching insect orders, including Zygentoma (silverfish and firebrats) and Diplura (two-pronged bristletails). Mod(mdg4) is most likely a derived feature of Neoptera, while Pita is likely an evolutionary novelty of holometabolous insects. Zw5 appears to be restricted to schizophoran flies, whereas BEAF-32, ZIPIC and the Elba complex, are probably unique to the genus Drosophila. Selection models indicate that insect IBPs evolved under neutral or purifying selection. Conclusions Our results suggest that a substantial number of IBPs either pre-date the evolution of insects or evolved early during insect evolution. This suggests an evolutionary history of insulator binding proteins in insects different to that previously thought. Moreover, our study demonstrates the versatility of the 1KITE transcriptomic data for comparative analyses in insects and other arthropods. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3205-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Thomas Pauli
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany.
| | - Lucia Vedder
- University of Tübingen, Geschwister-Scholl-Platz, 72074, Tübingen, Germany
| | - Daniel Dowling
- Johannes Gutenberg University Mainz, Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Malte Petersen
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany
| | - Karen Meusemann
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany.,Department for Evolutionary Biology and Ecology (Institut for Biology I, Zoology), University of Freiburg, Hauptstr. 1, 79104, Freiburg, Germany.,Australian National Insect Collection, CSIRO National Research Collections Australia, Clunies Ross Street, Acton, ACT, 2601, Australia
| | - Alexander Donath
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany
| | - Ralph S Peters
- Zoological Research Museum Alexander Koenig, Arthropod Department, Adenauerallee 160, 53113, Bonn, Germany
| | - Lars Podsiadlowski
- University of Bonn, Institute of Evolutionary Biology and Ecology, An der Immenburg 1, 53121, Bonn, Germany
| | - Christoph Mayer
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany
| | - Shanlin Liu
- China National GeneBank-Shenzhen, BGI-Shenzhen, Shenzhen, Guangdong Province, 518083, China.,Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350, Copenhagen, Denmark
| | - Xin Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, 100193, China.,College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Peter Heger
- University of Cologne, Cologne Biocenter, Institute for Genetics, Zülpicher Straße 47a, 50674, Köln, Germany
| | - Thomas Wiehe
- University of Cologne, Cologne Biocenter, Institute for Genetics, Zülpicher Straße 47a, 50674, Köln, Germany
| | - Lars Hering
- Department of Zoology, University of Kassel, Heinrich-Plett-Str. 40, 34132, Kassel, Germany
| | - Georg Mayer
- Department of Zoology, University of Kassel, Heinrich-Plett-Str. 40, 34132, Kassel, Germany
| | - Bernhard Misof
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany
| | - Oliver Niehuis
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany.
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Jukam D, Viets K, Anderson C, Zhou C, DeFord P, Yan J, Cao J, Johnston RJ. The insulator protein BEAF-32 is required for Hippo pathway activity in the terminal differentiation of neuronal subtypes. Development 2016; 143:2389-97. [PMID: 27226322 DOI: 10.1242/dev.134700] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 05/11/2016] [Indexed: 01/07/2023]
Abstract
The Hippo pathway is crucial for not only normal growth and apoptosis but also cell fate specification during development. What controls Hippo pathway activity during cell fate specification is incompletely understood. In this article, we identify the insulator protein BEAF-32 as a regulator of Hippo pathway activity in Drosophila photoreceptor differentiation. Though morphologically uniform, the fly eye is composed of two subtypes of R8 photoreceptor neurons defined by expression of light-detecting Rhodopsin proteins. In one R8 subtype, active Hippo signaling induces Rhodopsin 6 (Rh6) and represses Rhodopsin 5 (Rh5), whereas in the other subtype, inactive Hippo signaling induces Rh5 and represses Rh6. The activity state of the Hippo pathway in R8 cells is determined by the expression of warts, a core pathway kinase, which interacts with the growth regulator melted in a double-negative feedback loop. We show that BEAF-32 is required for expression of warts and repression of melted Furthermore, BEAF-32 plays a second role downstream of Warts to induce Rh6 and prevent Rh5 fate. BEAF-32 is dispensable for Warts feedback, indicating that BEAF-32 differentially regulates warts and Rhodopsins. Loss of BEAF-32 does not noticeably impair the functions of the Hippo pathway in eye growth regulation. Our study identifies a context-specific regulator of Hippo pathway activity in post-mitotic neuronal fate, and reveals a developmentally specific role for a broadly expressed insulator protein.
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Affiliation(s)
- David Jukam
- Center for Developmental Genetics, Department of Biology, New York University, 100 Washington Square East, New York, NY 10003-6688, USA
| | - Kayla Viets
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2685, USA
| | - Caitlin Anderson
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2685, USA
| | - Cyrus Zhou
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2685, USA
| | - Peter DeFord
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2685, USA
| | - Jenny Yan
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2685, USA
| | - Jinshuai Cao
- Center for Developmental Genetics, Department of Biology, New York University, 100 Washington Square East, New York, NY 10003-6688, USA
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2685, USA
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