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Chavan A, Isenhart R, Nguyen SC, Kotb N, Harke J, Sintsova A, Ulukaya G, Uliana F, Ashiono C, Kutay U, Pegoraro G, Rangan P, Joyce EF, Jagannathan M. A nuclear architecture screen in Drosophila identifies Stonewall as a link between chromatin position at the nuclear periphery and germline stem cell fate. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.17.567611. [PMID: 38014085 PMCID: PMC10680830 DOI: 10.1101/2023.11.17.567611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The association of genomic loci to the nuclear periphery is proposed to facilitate cell-type specific gene repression and influence cell fate decisions. However, the interplay between gene position and expression remains incompletely understood, in part because the proteins that position genomic loci at the nuclear periphery remain unidentified. Here, we used an Oligopaint-based HiDRO screen targeting ~1000 genes to discover novel regulators of nuclear architecture in Drosophila cells. We identified the heterochromatin-associated protein, Stonewall (Stwl), as a factor promoting perinuclear chromatin positioning. In female germline stem cells (GSCs), Stwl binds and positions chromatin loci, including GSC differentiation genes, at the nuclear periphery. Strikingly, Stwl-dependent perinuclear positioning is associated with transcriptional repression, highlighting a likely mechanism for Stwl's known role in GSC maintenance and ovary homeostasis. Thus, our study identifies perinuclear anchors in Drosophila and demonstrates the importance of gene repression at the nuclear periphery for cell fate.
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Affiliation(s)
- Ankita Chavan
- Institute of Biochemistry, Department of Biology, ETH Zürich, Switzerland
- Bringing Materials to Life Consortium, ETH Zürich, Switzerland
- Life Science Zurich Graduate School, Zürich, Switzerland
- These authors contributed equally
| | - Randi Isenhart
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- These authors contributed equally
| | - Son C. Nguyen
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Noor Kotb
- Department of Cell, Developmental and Regenerative Biology, Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jailynn Harke
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anna Sintsova
- Institute of Microbiology, Department of Biology, ETH Zürich, Switzerland
| | - Gulay Ulukaya
- Bioinformatics for Next Generation Sequencing (BiNGS) core, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Federico Uliana
- Institute of Biochemistry, Department of Biology, ETH Zürich, Switzerland
| | - Caroline Ashiono
- Institute of Biochemistry, Department of Biology, ETH Zürich, Switzerland
| | - Ulrike Kutay
- Institute of Biochemistry, Department of Biology, ETH Zürich, Switzerland
| | - Gianluca Pegoraro
- High Throughput Imaging Facility (HiTIF), National Cancer Institute, NIH, Bethesda, MD 20892 USA
| | - Prashanth Rangan
- Department of Cell, Developmental and Regenerative Biology, Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Eric F. Joyce
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Madhav Jagannathan
- Institute of Biochemistry, Department of Biology, ETH Zürich, Switzerland
- Bringing Materials to Life Consortium, ETH Zürich, Switzerland
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Finger DS, Whitehead KM, Phipps DN, Ables ET. Nuclear receptors linking physiology and germline stem cells in Drosophila. VITAMINS AND HORMONES 2021; 116:327-362. [PMID: 33752824 PMCID: PMC8063499 DOI: 10.1016/bs.vh.2020.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Maternal nutrition and physiology are intimately associated with reproductive success in diverse organisms. Despite decades of study, the molecular mechanisms linking maternal diet to the production and quality of oocytes remain poorly defined. Nuclear receptors (NRs) link nutritional signals to cellular responses and are essential for oocyte development. The fruit fly, Drosophila melanogaster, is an excellent genetically tractable model to study the relationship between NR signaling and oocyte production. In this review, we explore how NRs in Drosophila regulate the earliest stages of oocyte development. Long-recognized as an essential mediator of developmental transitions, we focus on the intrinsic roles of the Ecdysone Receptor and its ligand, ecdysone, in oogenesis. We also review recent studies suggesting broader roles for NRs as regulators of maternal physiology and their impact specifically on oocyte production. We propose that NRs form the molecular basis of a broad physiological surveillance network linking maternal diet with oocyte production. Given the functional conservation between Drosophila and humans, continued experimental investigation into the molecular mechanisms by which NRs promote oogenesis will likely aid our understanding of human fertility.
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Affiliation(s)
- Danielle S Finger
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Kaitlin M Whitehead
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Daniel N Phipps
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Elizabeth T Ables
- Department of Biology, East Carolina University, Greenville, NC, United States.
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He G, Mu T, Yuan Y, Yang W, Zhang Y, Chen Q, Bian M, Pan Y, Xiang Q, Chen Z, Sun A. Effects of Notch Signaling Pathway in Cervical Cancer by Curcumin Mediated Photodynamic Therapy and Its Possible Mechanisms in Vitro and in Vivo. J Cancer 2019; 10:4114-4122. [PMID: 31417656 PMCID: PMC6692604 DOI: 10.7150/jca.30690] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 05/05/2019] [Indexed: 02/07/2023] Open
Abstract
Curcumin, as a high effect and low toxicity anti-cancer drug and photosensitiser, has synergistic and complementary effects with photodynamic therapy (PDT). However, due to its unclear mechanism, PDT's application and efficacy were limited. Notch signaling pathway, which is highly correlates with carcinogenesis and development of cervical cancer, could be a potential therapeutic targets to improve the effectiveness of PDT. Therefore, in this study, we explored the effects of Notch signaling pathway in cervical cancer by curcumin mediated PDT with/without Notch receptor blocker (DAPT), and hope to elucidate its mechanism. Firstly, the effect on the proliferation of cervical cancer Me180 cells were detected with MTT assay, and apoptosis were detected with Annexin V-FITC/PI combined with flow cytometry. Secondly, after establishment of nude mice model, dividing the experimental animals into model group, curcumin PDT group, simple DAPT group, and curcumin-PDT+DAPT group, and analyzing tumor volume changes as well as HE staining in each group. mRNA and protein expression of gene Notch-1 and its downstream NF-κB and VEGF were observed with RT-PCR, immunohistochemical staining and Western-blot with/without inhibition of Notch signaling pathway by DAPT, both in vivo and in vitro experiments. We found both DAPT and curcumin-PDT can inhibit the proliferation and induce apoptosis of cervical cancer cell. The two have synergistic effect in vitro and in vivo. This effect can effectively block the conduction of Notch signaling pathway, which is associated with down-regulation of the expression of Notch1 and NF-κB. Notch signaling pathway could be one of the targets of curcumin-PDT photodynamic therapy.
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Affiliation(s)
- Guifang He
- Department of Gynecology & Obstetrics, China-Japan Friendship Hospital, Beijing, China, 100029
| | - Tianlong Mu
- Department of Pathology, Oriental Hospital of Beijing University of Chinese Medicine, Beijing, China, 100078
| | - Yali Yuan
- China-Japan Friendship School of Clinical Medicine, Peking University, Beijing, China, 100029
| | - Wenyan Yang
- China-Japan Friendship School of Clinical Medicine, Peking University, Beijing, China, 100029
| | - Yuan Zhang
- China-Japan Friendship School of Clinical Medicine, Peking University, Beijing, China, 100029
| | - Qingyun Chen
- Department of Gynecology & Obstetrics, China-Japan Friendship Hospital, Beijing, China, 100029
| | - Meilu Bian
- Department of Gynecology & Obstetrics, China-Japan Friendship Hospital, Beijing, China, 100029
| | - Yanshu Pan
- Department of Pathology, School of Basic Medical Sciences, Beijing University of Chinese Medicine, Beijing, China, 100029
| | - Qing Xiang
- Department of Biochemistry & Molecular Biology, Institute of Clinical Medical Science, China-Japan Friendship Hospital, Beijing , China, 100029
| | - Zhihua Chen
- Department of Biochemistry & Molecular Biology, Institute of Clinical Medical Science, China-Japan Friendship Hospital, Beijing , China, 100029
| | - Aiping Sun
- Department of Gynecology & Obstetrics, China-Japan Friendship Hospital, Beijing, China, 100029
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Mazina MY, Vorobyeva NE. Mechanisms of transcriptional regulation of ecdysone response. Vavilovskii Zhurnal Genet Selektsii 2019. [DOI: 10.18699/vj19.484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The mechanisms of ecdysone-dependent expression have been studied for many decades. Initially, the activation of individual genes under the influence of ecdysone was studied on the model of polythene chromosomes from salivary glands of Drosophila melanogaster. These works helped to investigate the many aspects of the Drosophila development. They also revealed plenty of valuable information regarding the fundamental mechanisms controlling the genes’ work. Many years ago, a model describing the process of gene activation by ecdysone, named after the author – Ashburner model – was proposed. This model is still considered an excellent description of the ecdysone cascade, which is implemented in the salivary glands during the formation of the Drosophila pupa. However, these days there is an opinion that the response of cells to the hormone ecdysone can develop with significant differences, depending on the type of cells. The same genes can be activated or repressed under the influence of ecdysone in different tissues. Likely, certain DNA-binding transcription factors that are involved in the ecdysonedependent response together with the EcR/Usp heterodimer are responsible for cell-type specificity. A number of transcriptional regulators involved in the ecdysone response have been described. Among them are several complexes responsible for chromatin remodeling and modification. It has been shown by various methods that ecdysone-dependent activation/repression of gene transcription develops with significant structural changes of chromatin on regulatory elements. The description of the molecular mechanism of this process, in particular, the role of individual proteins in it, as well as structural interactions between various regulatory elements is a matter of the future. This review is aimed to discuss the available information regarding the main regulators that interact with the ecdysone receptor. We provide a brief description of the regulator’s participation in the ecdysone response and links to the corresponding study. We also discuss general aspects of the mechanism of ecdysone-dependent regulation and highlight the most promising points for further research.
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Affiliation(s)
- M. Yu. Mazina
- Institute of Gene Biology, RAS, Group of transcriptional complexes dynamics
| | - N. E. Vorobyeva
- Institute of Gene Biology, RAS, Group of transcriptional complexes dynamics
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Chan SKK, Cerda-Moya G, Stojnic R, Millen K, Fischer B, Fexova S, Skalska L, Gomez-Lamarca M, Pillidge Z, Russell S, Bray SJ. Role of co-repressor genomic landscapes in shaping the Notch response. PLoS Genet 2017; 13:e1007096. [PMID: 29155828 PMCID: PMC5714389 DOI: 10.1371/journal.pgen.1007096] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 12/04/2017] [Accepted: 11/01/2017] [Indexed: 11/18/2022] Open
Abstract
Repressors are frequently deployed to limit the transcriptional response to signalling pathways. For example, several co-repressors interact directly with the DNA-binding protein CSL and are proposed to keep target genes silenced in the absence of Notch activity. However, the scope of their contributions remains unclear. To investigate co-repressor activity in the context of this well defined signalling pathway, we have analysed the genome-wide binding profile of the best-characterized CSL co-repressor in Drosophila, Hairless, and of a second CSL interacting repressor, SMRTER. As predicted there was significant overlap between Hairless and its CSL DNA-binding partner, both in Kc cells and in wing discs, where they were predominantly found in chromatin with active enhancer marks. However, while the Hairless complex was widely present at some Notch regulated enhancers in the wing disc, no binding was detected at others, indicating that it is not essential for silencing per se. Further analysis of target enhancers confirmed differential requirements for Hairless. SMRTER binding significantly overlapped with Hairless, rather than complementing it, and many enhancers were apparently co-bound by both factors. Our analysis indicates that the actions of Hairless and SMRTER gate enhancers to Notch activity and to Ecdysone signalling respectively, to ensure that the appropriate levels and timing of target gene expression are achieved. The communication between cells that occurs during development, as well as in disease contexts, involves a small number of signalling pathways of which the Notch pathway is one. One outstanding question is how these pathways can bring about different gene responses in different contexts. As gene expression is co-ordinated by a mixture of activators and repressors, we set out to investigate whether the distribution of repressors across the genome is important in shaping whether genes are able to respond to Notch activity. Our results from analyzing the binding profile of two repressors, Hairless and SMRTER, show that, in many cases, they are not essential for preventing a gene from responding. Instead they are deployed at a limited number of genetic loci where they gate the response, helping to set a threshold for gene activation. Perturbations to their function lead to enhanced gene expression in limited territories rather than to new programmes of gene expression. Their main role therefore is to restrict the time or levels of signal that a gene needs to receive before it will respond.
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Affiliation(s)
- Stephen K. K. Chan
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Gustavo Cerda-Moya
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Robert Stojnic
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge, United Kingdom
| | - Kat Millen
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Bettina Fischer
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Silvie Fexova
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Lenka Skalska
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Maria Gomez-Lamarca
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Zoe Pillidge
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Steven Russell
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Sarah J. Bray
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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6
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Guo Y, Flegel K, Kumar J, McKay DJ, Buttitta LA. Ecdysone signaling induces two phases of cell cycle exit in Drosophila cells. Biol Open 2016; 5:1648-1661. [PMID: 27737823 PMCID: PMC5155522 DOI: 10.1242/bio.017525] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
During development, cell proliferation and differentiation must be tightly coordinated to ensure proper tissue morphogenesis. Because steroid hormones are central regulators of developmental timing, understanding the links between steroid hormone signaling and cell proliferation is crucial to understanding the molecular basis of morphogenesis. Here we examined the mechanism by which the steroid hormone ecdysone regulates the cell cycle in Drosophila. We find that a cell cycle arrest induced by ecdysone in Drosophila cell culture is analogous to a G2 cell cycle arrest observed in the early pupa wing. We show that in the wing, ecdysone signaling at the larva-to-puparium transition induces Broad which in turn represses the cdc25c phosphatase String. The repression of String generates a temporary G2 arrest that synchronizes the cell cycle in the wing epithelium during early pupa wing elongation and flattening. As ecdysone levels decline after the larva-to-puparium pulse during early metamorphosis, Broad expression plummets, allowing String to become re-activated, which promotes rapid G2/M progression and a subsequent synchronized final cell cycle in the wing. In this manner, pulses of ecdysone can both synchronize the final cell cycle and promote the coordinated acquisition of terminal differentiation characteristics in the wing. Summary: Pulsed ecdysone signaling remodels cell cycle dynamics, causing distinct primary and secondary cell cycle arrests in Drosophila cells, analogous to those observed in the wing during metamorphosis.
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Affiliation(s)
- Yongfeng Guo
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kerry Flegel
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jayashree Kumar
- Biology Department and Genetics Department, Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Daniel J McKay
- Biology Department and Genetics Department, Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laura A Buttitta
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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7
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The Ecdysone and Notch Pathways Synergistically Regulate Cut at the Dorsal-Ventral Boundary in Drosophila Wing Discs. J Genet Genomics 2016; 43:179-86. [PMID: 27117286 DOI: 10.1016/j.jgg.2016.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/05/2016] [Accepted: 03/04/2016] [Indexed: 11/23/2022]
Abstract
Metazoan development requires coordination of signaling pathways to regulate patterns of gene expression. In Drosophila, the wing imaginal disc provides an excellent model for the study of how signaling pathways interact to regulate pattern formation. The determination of the dorsal-ventral (DV) boundary of the wing disc depends on the Notch pathway, which is activated along the DV boundary and induces the expression of the homeobox transcription factor, Cut. Here, we show that Broad (Br), a zinc-finger transcription factor, is also involved in regulating Cut expression in the DV boundary region. However, Br expression is not regulated by Notch signaling in wing discs, while ecdysone signaling is the upstream signal that induces Br for Cut upregulation. Also, we find that the ecdysone-Br cascade upregulates cut-lacZ expression, a reporter containing a 2.7 kb cut enhancer region, implying that ecdysone signaling, similar to Notch, regulates cut at the transcriptional level. Collectively, our findings reveal that the Notch and ecdysone signaling pathways synergistically regulate Cut expression for proper DV boundary formation in the wing disc. Additionally, we show br promotes Delta, a Notch ligand, near the DV boundary to suppress aberrant high Notch activity, indicating further interaction between the two pathways for DV patterning of the wing disc.
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Oswald F, Rodriguez P, Giaimo BD, Antonello ZA, Mira L, Mittler G, Thiel VN, Collins KJ, Tabaja N, Cizelsky W, Rothe M, Kühl SJ, Kühl M, Ferrante F, Hein K, Kovall RA, Dominguez M, Borggrefe T. A phospho-dependent mechanism involving NCoR and KMT2D controls a permissive chromatin state at Notch target genes. Nucleic Acids Res 2016; 44:4703-20. [PMID: 26912830 PMCID: PMC4889922 DOI: 10.1093/nar/gkw105] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 02/11/2016] [Indexed: 01/24/2023] Open
Abstract
The transcriptional shift from repression to activation of target genes is crucial for the fidelity of Notch responses through incompletely understood mechanisms that likely involve chromatin-based control. To activate silenced genes, repressive chromatin marks are removed and active marks must be acquired. Histone H3 lysine-4 (H3K4) demethylases are key chromatin modifiers that establish the repressive chromatin state at Notch target genes. However, the counteracting histone methyltransferase required for the active chromatin state remained elusive. Here, we show that the RBP-J interacting factor SHARP is not only able to interact with the NCoR corepressor complex, but also with the H3K4 methyltransferase KMT2D coactivator complex. KMT2D and NCoR compete for the C-terminal SPOC-domain of SHARP. We reveal that the SPOC-domain exclusively binds to phosphorylated NCoR. The balance between NCoR and KMT2D binding is shifted upon mutating the phosphorylation sites of NCoR or upon inhibition of the NCoR kinase CK2β. Furthermore, we show that the homologs of SHARP and KMT2D in Drosophila also physically interact and control Notch-mediated functions in vivo. Together, our findings reveal how signaling can fine-tune a committed chromatin state by phosphorylation of a pivotal chromatin-modifier.
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Affiliation(s)
- Franz Oswald
- University Medical Center Ulm, Center for Internal Medicine, Department of Internal Medicine I, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - Patrick Rodriguez
- Swiss Institute for Experimental Cancer Research, Lausanne, Switzerland
| | - Benedetto Daniele Giaimo
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany Spemann Graduate School of Biology and Medicine (SGBM), Faculty of Biology, Albert Ludwigs University Freiburg, Germany
| | - Zeus A Antonello
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas-Universidad Miguel Hernández, Campus de Sant Joan, Alicante, Spain
| | - Laura Mira
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas-Universidad Miguel Hernández, Campus de Sant Joan, Alicante, Spain
| | - Gerhard Mittler
- Max-Planck-Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108 Freiburg, Germany
| | - Verena N Thiel
- University Medical Center Ulm, Center for Internal Medicine, Department of Internal Medicine I, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - Kelly J Collins
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Nassif Tabaja
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Wiebke Cizelsky
- Institute for Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany International Graduate School in Molecular Medicine Ulm (IGradU), Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Melanie Rothe
- Institute for Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany International Graduate School in Molecular Medicine Ulm (IGradU), Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Susanne J Kühl
- Institute for Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Michael Kühl
- Institute for Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Francesca Ferrante
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany
| | - Kerstin Hein
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany
| | - Rhett A Kovall
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Maria Dominguez
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas-Universidad Miguel Hernández, Campus de Sant Joan, Alicante, Spain
| | - Tilman Borggrefe
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany
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A large-scale in vivo RNAi screen to identify genes involved in Notch-mediated follicle cell differentiation and cell cycle switches. Sci Rep 2015. [PMID: 26205122 PMCID: PMC4513280 DOI: 10.1038/srep12328] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
During Drosophila oogenesis, follicle cells sequentially undergo three distinct cell-cycle programs: the mitotic cycle, endocycle, and gene amplification. Notch signaling plays a central role in regulating follicle-cell differentiation and cell-cycle switches; its activation is essential for the mitotic cycle/endocycle (M/E) switch. Cut, a linker between Notch signaling and cell-cycle regulators, is specifically downregulated by Notch during the endocycle stage. To determine how signaling pathways coordinate during the M/E switch and to identify novel genes involved in follicle cell differentiation, we performed an in vivo RNAi screen through induced knockdown of gene expression and examination of Cut expression in follicle cells. We screened 2205 RNAi lines and found 33 genes regulating Cut expression during the M/E switch. These genes were confirmed with the staining of two other Notch signaling downstream factors, Hindsight and Broad, and validated with multiple independent RNAi lines. We applied gene ontology software to find enriched biological meaning and compared our results with other publications to find conserved genes across tissues. Specifically, we found earlier endocycle entry in anterior follicle cells than those in the posterior, identified that the insulin-PI3K pathway participates in the precise M/E switch, and suggested Nejire as a cofactor of Notch signaling during oogenesis.
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Regulation of broad by the Notch pathway affects timing of follicle cell development. Dev Biol 2014; 392:52-61. [PMID: 24815210 DOI: 10.1016/j.ydbio.2014.04.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/23/2014] [Accepted: 04/29/2014] [Indexed: 12/20/2022]
Abstract
During Drosophila oogenesis, activation of Notch signaling in the follicular epithelium (FE) around stage 6 of oogenesis is essential for entry into the endocycle and a series of other changes such as cell differentiation and migration of subsets of the follicle cells. Notch induces the expression of zinc finger protein Hindsight and suppresses homeodomain protein Cut to regulate the mitotic/endocycle (ME) switch. Here we report that broad (br), encoding a small group of zinc-finger transcription factors resulting from alternative splicing, is a transcriptional target of Notch nuclear effector Suppressor of Hairless (Su(H)). The early pattern of Br in the FE, uniformly expressed except in the polar cells, is established by Notch signaling around stage 6, through the binding of Su(H) to the br early enhancer (brE) region. Mutation of the Su(H) binding site leads to a significant reduction of brE reporter expression in follicle cells undergoing the endocycle. Chromatin immunoprecipitation results further confirm Su(H) binding to the br early enhancer. Consistent with its expression in follicle cells during midoogenesis, loss of br function results in a delayed entry into the endocycle. Our findings suggest an important role of br in the timing of follicle cell development, and its transcriptional regulation by the Notch pathway.
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11
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Koe CT, Li S, Rossi F, Wong JJL, Wang Y, Zhang Z, Chen K, Aw SS, Richardson HE, Robson P, Sung WK, Yu F, Gonzalez C, Wang H. The Brm-HDAC3-Erm repressor complex suppresses dedifferentiation in Drosophila type II neuroblast lineages. eLife 2014; 3:e01906. [PMID: 24618901 PMCID: PMC3944433 DOI: 10.7554/elife.01906] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The control of self-renewal and differentiation of neural stem and progenitor cells is a crucial issue in stem cell and cancer biology. Drosophila type II neuroblast lineages are prone to developing impaired neuroblast homeostasis if the limited self-renewing potential of intermediate neural progenitors (INPs) is unrestrained. Here, we demonstrate that Drosophila SWI/SNF chromatin remodeling Brahma (Brm) complex functions cooperatively with another chromatin remodeling factor, Histone deacetylase 3 (HDAC3) to suppress the formation of ectopic type II neuroblasts. We show that multiple components of the Brm complex and HDAC3 physically associate with Earmuff (Erm), a type II-specific transcription factor that prevents dedifferentiation of INPs into neuroblasts. Consistently, the predicted Erm-binding motif is present in most of known binding loci of Brm. Furthermore, brm and hdac3 genetically interact with erm to prevent type II neuroblast overgrowth. Thus, the Brm-HDAC3-Erm repressor complex suppresses dedifferentiation of INPs back into type II neuroblasts. DOI:http://dx.doi.org/10.7554/eLife.01906.001 Stem cells show great promise for repairing damaged tissue, and maybe even generating new organs, but stem cell therapies will only be successful if researchers can understand and control the behaviour of stem cells in the lab. Neural stem cells or ‘neuroblasts’ from the brains of larval fruit flies have become a popular model for studying these processes, and one type of neuroblast—known as a ‘type II’ neuroblast—is similar to mammalian neural stem cells in many ways. When type II neuroblasts divide, they generate another neuroblast and a second cell called an intermediate neural progenitor (INP) cell. This progenitor cell then matures and undergoes a limited number of divisions to generate more INP cells and cells called ganglion mother cells. The process by which stem cells and INP cells become specific types of cells is known as differentiation. However, under certain circumstances, the INP cells can undergo the opposite process, which is called dedifferentiation, and become ‘ectopic neuroblasts’. This can give rise to tumors, so cells must employ a mechanism to prevent dedifferentiation. Researchers have known that a protein specifically expressed in INP cells called Earmuff is involved in this process, but many of the details have remained hidden. Now, Koe et al. have discovered that a multi-protein complex containing Earmuff and a number of other proteins—Brahma and HDAC3—have important roles in preventing dedifferentiation. All three proteins are involved in different aspects of gene expression: Earmuff is a transcription factor that controls the process by which the genes in DNA are transcribed to make molecules of messenger RNA; Brahma and HDAC3 are both involved in a process called chromatin remodeling. The DNA inside cells is packaged into a compact structure known as chromatin, and chromatin remodeling involves partially unpacking this structure so that transcription factors and other proteins can have access to the DNA. Koe et al. also showed that Earmuff, Brahma and HDAC3 combine to form a complex that prevents dedifferentiation. An immediate priority is to identify those genes whose expression is regulated by this complex in order to prevent dedifferentiation. DOI:http://dx.doi.org/10.7554/eLife.01906.002
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Affiliation(s)
- Chwee Tat Koe
- Neuroscience and Behavioral Disorders Program, Duke-NUS Graduate Medical School Singapore, Singapore, Singapore
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Abstract
Although intercellular bridges resulting from incomplete cytokinesis were discovered in somatic Drosophila tissues decades ago, the impact of these structures on intercellular communication and tissue biology is largely unknown. In this work, we demonstrate that the ~250-nanometer-diameter somatic ring canals permit diffusion of cytoplasmic contents between connected cells and across mitotic clone boundaries and enable the equilibration of protein between transcriptionally mosaic follicle cells in the Drosophila ovary. We obtained similar, although more restricted, results in the larval imaginal discs. Our work illustrates the lack of cytoplasmic autonomy in these tissues and suggests a role for somatic ring canals in promoting homogeneous protein expression within the tissue.
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Affiliation(s)
- Peter F McLean
- Department of Genetics, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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