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DeHaro-Arbona FJ, Roussos C, Baloul S, Townson J, Gómez Lamarca MJ, Bray S. Dynamic modes of Notch transcription hubs conferring memory and stochastic activation revealed by live imaging the co-activator Mastermind. eLife 2024; 12:RP92083. [PMID: 38727722 PMCID: PMC11087053 DOI: 10.7554/elife.92083] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024] Open
Abstract
Developmental programming involves the accurate conversion of signalling levels and dynamics to transcriptional outputs. The transcriptional relay in the Notch pathway relies on nuclear complexes containing the co-activator Mastermind (Mam). By tracking these complexes in real time, we reveal that they promote the formation of a dynamic transcription hub in Notch ON nuclei which concentrates key factors including the Mediator CDK module. The composition of the hub is labile and persists after Notch withdrawal conferring a memory that enables rapid reformation. Surprisingly, only a third of Notch ON hubs progress to a state with nascent transcription, which correlates with polymerase II and core Mediator recruitment. This probability is increased by a second signal. The discovery that target-gene transcription is probabilistic has far-reaching implications because it implies that stochastic differences in Notch pathway output can arise downstream of receptor activation.
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Affiliation(s)
- F Javier DeHaro-Arbona
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Charalambos Roussos
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Sarah Baloul
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Jonathan Townson
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - María J Gómez Lamarca
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocıo/CSIC/Universidad de Sevilla, Departamento de Biologıa CelularSevilleSpain
| | - Sarah Bray
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
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2
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Schiano C, Luongo L, Maione S, Napoli C. Mediator complex in neurological disease. Life Sci 2023; 329:121986. [PMID: 37516429 DOI: 10.1016/j.lfs.2023.121986] [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: 02/13/2023] [Revised: 07/18/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Neurological diseases, including traumatic brain injuries, stroke (haemorrhagic and ischemic), and inherent neurodegenerative diseases cause acquired disability in humans, representing a leading cause of death worldwide. The Mediator complex (MED) is a large, evolutionarily conserved multiprotein that facilities the interaction between transcription factors and RNA Polymerase II in eukaryotes. Some MED subunits have been found altered in the brain, although their specific functions in neurodegenerative diseases are not fully understood. Mutations in MED subunits were associated with a wide range of genetic diseases for MED12, MED13, MED13L, MED20, MED23, MED25, and CDK8 genes. In addition, MED12 and MED23 were deregulated in the Alzheimer's Disease. Interestingly, most of the genomic mutations have been found in the subunits of the kinase module. To date, there is only one evidence on MED1 involvement in post-stroke cognitive deficits. Although the underlying neurodegenerative disorders may be different, we are confident that the signal cascades of the biological-cognitive mechanisms of brain adaptation, which begin after brain deterioration, may also differ. Here, we analysed relevant studies in English published up to June 2023. They were identified through a search of electronic databases including PubMed, Medline, EMBASE and Scopus, including search terms such as "Mediator complex", "neurological disease", "brains". Thematic content analysis was conducted to collect and summarize all studies demonstrating MED alteration to understand the role of this central transcriptional regulatory complex in the brain. Improved and deeper knowledge of the regulatory mechanisms in neurological diseases can increase the ability of physicians to predict onset and progression, thereby improving diagnostic care and providing appropriate treatment decisions.
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Affiliation(s)
- Concetta Schiano
- Department of Advanced Medical and Surgical Sciences (DAMSS), University of Campania "Luigi Vanvitelli", Italy.
| | - Livio Luongo
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Italy; IRCSS, Neuromed, Pozzilli, Italy
| | - Sabatino Maione
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Italy; IRCSS, Neuromed, Pozzilli, Italy
| | - Claudio Napoli
- Department of Advanced Medical and Surgical Sciences (DAMSS), University of Campania "Luigi Vanvitelli", Italy; Clinical Department of Internal Medicine and Specialistic Units, Division of Clinical Immunology and Immunohematology, Transfusion Medicine, and Transplant Immunology (SIMT), Regional Reference Laboratory of Transplant Immunology (LIT), Azienda Universitaria Policlinico (AOU), Italy
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3
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Zaytseva O, Mitchell NC, Muckle D, Delandre C, Nie Z, Werner JK, Lis JT, Eyras E, Hannan RD, Levens DL, Marshall OJ, Quinn LM. Psi promotes Drosophila wing growth via direct transcriptional activation of cell cycle targets and repression of growth inhibitors. Development 2023; 150:286725. [PMID: 36692218 PMCID: PMC10110491 DOI: 10.1242/dev.201563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/03/2023] [Indexed: 01/25/2023]
Abstract
The first characterised FUSE Binding Protein family member, FUBP1, binds single-stranded DNA to activate MYC transcription. Psi, the sole FUBP protein in Drosophila, binds RNA to regulate P-element and mRNA splicing. Our previous work revealed pro-growth functions for Psi, which depend, in part, on transcriptional activation of Myc. Genome-wide functions for FUBP family proteins in transcriptional control remain obscure. Here, through the first genome-wide binding and expression profiles obtained for a FUBP family protein, we demonstrate that, in addition to being required to activate Myc to promote cell growth, Psi also directly binds and activates stg to couple growth and cell division. Thus, Psi knockdown results in reduced cell division in the wing imaginal disc. In addition to activating these pro-proliferative targets, Psi directly represses transcription of the growth inhibitor tolkin (tok, a metallopeptidase implicated in TGFβ signalling). We further demonstrate tok overexpression inhibits proliferation, while tok loss of function increases mitosis alone and suppresses impaired cell division caused by Psi knockdown. Thus, Psi orchestrates growth through concurrent transcriptional activation of the pro-proliferative genes Myc and stg, in combination with repression of the growth inhibitor tok.
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Affiliation(s)
- Olga Zaytseva
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia
| | - Naomi C Mitchell
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia
| | - Damien Muckle
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia
| | - Caroline Delandre
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania 7000, Australia
| | - Zuqin Nie
- National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | | | - John T Lis
- Cornell University, Ithaca, NY 14850, USA
| | - Eduardo Eyras
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia
| | - Ross D Hannan
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia
| | | | - Owen J Marshall
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania 7000, Australia
| | - Leonie M Quinn
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia
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4
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Jullien D, Guillou E, Bernat-Fabre S, Payet A, Bourbon HMG, Boube M. Inducible degradation of the Drosophila Mediator subunit Med19 reveals its role in regulating developmental but not constitutively-expressed genes. PLoS One 2022; 17:e0275613. [PMID: 36445897 PMCID: PMC9707739 DOI: 10.1371/journal.pone.0275613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/20/2022] [Indexed: 11/30/2022] Open
Abstract
The multi-subunit Mediator complex plays a critical role in gene expression by bridging enhancer-bound transcription factors and the RNA polymerase II machinery. Although experimental case studies suggest differential roles of Mediator subunits, a comprehensive view of the specific set of genes regulated by individual subunits in a developing tissue is still missing. Here we address this fundamental question by focusing on the Med19 subunit and using the Drosophila wing imaginal disc as a developmental model. By coupling auxin-inducible degradation of endogenous Med19 in vivo with RNA-seq, we got access to the early consequences of Med19 elimination on gene expression. Differential gene expression analysis reveals that Med19 is not globally required for mRNA transcription but specifically regulates positively or negatively less than a quarter of the expressed genes. By crossing our transcriptomic data with those of Drosophila gene expression profile database, we found that Med19-dependent genes are highly enriched with spatially-regulated genes while the expression of most constitutively expressed genes is not affected upon Med19 loss. Whereas globally downregulation does not exceed upregulation, we identified a functional class of genes encoding spatially-regulated transcription factors, and more generally developmental regulators, responding unidirectionally to Med19 loss with an expression collapse. Moreover, we show in vivo that the Notch-responsive wingless and the E(spl)-C genes require Med19 for their expression. Combined with experimental evidences suggesting that Med19 could function as a direct transcriptional effector of Notch signaling, our data support a model in which Med19 plays a critical role in the transcriptional activation of developmental genes in response to cell signaling pathways.
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Affiliation(s)
- Denis Jullien
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
- * E-mail: (MB); (DJ)
| | - Emmanuelle Guillou
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
| | - Sandra Bernat-Fabre
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
| | - Adeline Payet
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
| | - Henri-Marc G. Bourbon
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
| | - Muriel Boube
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
- RESTORE Research Center, Université de Toulouse, INSERM 1301, CNRS 5070, EFS, ENVT, Toulouse, France
- * E-mail: (MB); (DJ)
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5
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Chang X, Zhang F, Li H, Mo D, Shen J, Zhang J. Characterization of a new mastermind allele identified from somatic mosaic screen. Cells Dev 2021; 165:203664. [PMID: 33993981 DOI: 10.1016/j.cdev.2021.203664] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 01/07/2021] [Accepted: 01/22/2021] [Indexed: 11/18/2022]
Abstract
The Notch signaling pathway is highly conserved and regulates various fundamental development events. Activation of Notch signaling relies on production of the Notch intracellular domain (NICD), which assembles a transcription factor complex to turn on down-stream targets expression. The mastermind (mam) gene encodes an essential co-activator that permits NICD activity in the cell nucleus. During a somatic mosaic screen in Drosophila, an uncharacterized gene l(2)S9998 is identified as a positive regulator of the Notch signaling pathway. Genetic analysis demonstrates that l(2)S9998 functions at the level of transcriptional activation of Notch targets in the signal receiving cells. Whole genome sequencing reveals that l(2)S9998 is a novel allele of the mam gene, which is further confirmed by complementation tests. Along with three molecularly defined transposon insertions isolated from the screen, four mutants of mam are shown to modulate Notch signaling during fly wing development. Our analysis provides additional genetic resources for understanding mam function and Notch signaling regulation.
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Affiliation(s)
- Xinyue Chang
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Fengchao Zhang
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Haomiao Li
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Dongqing Mo
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jie Shen
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Junzheng Zhang
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China.
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6
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Miao YL, Gambini A, Zhang Y, Padilla-Banks E, Jefferson WN, Bernhardt ML, Huang W, Li L, Williams CJ. Mediator complex component MED13 regulates zygotic genome activation and is required for postimplantation development in the mouse. Biol Reprod 2019; 98:449-464. [PMID: 29325037 DOI: 10.1093/biolre/ioy004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 01/08/2018] [Indexed: 12/21/2022] Open
Abstract
Understanding factors that regulate zygotic genome activation (ZGA) is critical for determining how cells are reprogrammed to become totipotent or pluripotent. There is limited information regarding how this process occurs physiologically in early mammalian embryos. Here, we identify a mediator complex subunit, MED13, as translated during mouse oocyte maturation and transcribed early from the zygotic genome. Knockdown and conditional knockout approaches demonstrate that MED13 is essential for ZGA in the mouse, in part by regulating expression of the embryo-specific chromatin remodeling complex, esBAF. The role of MED13 in ZGA is mediated in part by interactions with E2F transcription factors. In addition to MED13, its paralog, MED13L, is required for successful preimplantation embryo development. MED13L partially compensates for loss of MED13 function in preimplantation knockout embryos, but postimplantation development is not rescued by MED13L. Our data demonstrate an essential role for MED13 in supporting chromatin reprogramming and directed transcription of essential genes during ZGA.
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Affiliation(s)
- Yi-Liang Miao
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA.,Key Laboratory of Agricultural Animal Genetics, Breeding, and Reproduction, Ministry of Education College of Animal Science and Technology, Huazhong Agricultural University, China
| | - Andrés Gambini
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Yingpei Zhang
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Elizabeth Padilla-Banks
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Wendy N Jefferson
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Miranda L Bernhardt
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Weichun Huang
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Leping Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Carmen J Williams
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
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7
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A genetic mosaic screen identifies genes modulating Notch signaling in Drosophila. PLoS One 2018; 13:e0203781. [PMID: 30235233 PMCID: PMC6147428 DOI: 10.1371/journal.pone.0203781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 08/27/2018] [Indexed: 01/08/2023] Open
Abstract
Notch signaling is conserved in most multicellular organisms and plays critical roles during animal development. The core components and major signal transduction mechanism of Notch signaling have been extensively studied. However, our understanding of how Notch signaling activity is regulated in diverse developmental processes still remains incomplete. Here, we report a genetic mosaic screen in Drosophila melanogaster that leads to identification of Notch signali ng modulators during wing development. We discovered a group of genes required for the formation of the fly wing margin, a developmental process that is strictly dependent on the balanced Notch signaling activity. These genes encode transcription factors, protein phosphatases, vacuolar ATPases and factors required for RNA transport, stability, and translation. Our data support the view that Notch signaling is controlled through a wide range of molecular processes. These results also provide foundations for further study by showing that Me31B and Wdr62 function as two novel modulators of Notch signaling activity.
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8
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Park MJ, Shen H, Spaeth JM, Tolvanen JH, Failor C, Knudtson JF, McLaughlin J, Halder SK, Yang Q, Bulun SE, Al-Hendy A, Schenken RS, Aaltonen LA, Boyer TG. Oncogenic exon 2 mutations in Mediator subunit MED12 disrupt allosteric activation of cyclin C-CDK8/19. J Biol Chem 2018; 293:4870-4882. [PMID: 29440396 DOI: 10.1074/jbc.ra118.001725] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 01/28/2018] [Indexed: 01/26/2023] Open
Abstract
Somatic mutations in exon 2 of the RNA polymerase II transcriptional Mediator subunit MED12 occur at high frequency in uterine fibroids (UFs) and breast fibroepithelial tumors as well as recurrently, albeit less frequently, in malignant uterine leimyosarcomas, chronic lymphocytic leukemias, and colorectal cancers. Previously, we reported that UF-linked mutations in MED12 disrupt its ability to activate cyclin C (CycC)-dependent kinase 8 (CDK8) in Mediator, implicating impaired Mediator-associated CDK8 activity in the molecular pathogenesis of these clinically significant lesions. Notably, the CDK8 paralog CDK19 is also expressed in myometrium, and both CDK8 and CDK19 assemble into Mediator in a mutually exclusive manner, suggesting that CDK19 activity may also be germane to the pathogenesis of MED12 mutation-induced UFs. However, whether and how UF-linked mutations in MED12 affect CDK19 activation is unknown. Herein, we show that MED12 allosterically activates CDK19 and that UF-linked exon 2 mutations in MED12 disrupt its CDK19 stimulatory activity. Furthermore, we find that within the Mediator kinase module, MED13 directly binds to the MED12 C terminus, thereby suppressing an apparent UF mutation-induced conformational change in MED12 that otherwise disrupts its association with CycC-CDK8/19. Thus, in the presence of MED13, mutant MED12 can bind, but cannot activate, CycC-CDK8/19. These findings indicate that MED12 binding is necessary but not sufficient for CycC-CDK8/19 activation and reveal an additional step in the MED12-dependent activation process, one critically dependent on MED12 residues altered by UF-linked exon 2 mutations. These findings confirm that UF-linked mutations in MED12 disrupt composite Mediator-associated kinase activity and identify CDK8/19 as prospective therapeutic targets in UFs.
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Affiliation(s)
- Min Ju Park
- Departments of Molecular Medicine, San Antonio, Texas 78229
| | - Hailian Shen
- Departments of Molecular Medicine, San Antonio, Texas 78229
| | - Jason M Spaeth
- Departments of Molecular Medicine, San Antonio, Texas 78229
| | - Jaana H Tolvanen
- Genome-Scale Biology Program and Department of Medical Genetics, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland
| | - Courtney Failor
- Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Jennifer F Knudtson
- Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Jessica McLaughlin
- Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Sunil K Halder
- Department of Obstetrics and Gynecology, Augusta University, Augusta, Georgia 30912
| | - Qiwei Yang
- Department of Obstetrics and Gynecology, Augusta University, Augusta, Georgia 30912
| | - Serdar E Bulun
- Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Ayman Al-Hendy
- Department of Obstetrics and Gynecology, Augusta University, Augusta, Georgia 30912
| | - Robert S Schenken
- Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Lauri A Aaltonen
- Genome-Scale Biology Program and Department of Medical Genetics, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland
| | - Thomas G Boyer
- Departments of Molecular Medicine, San Antonio, Texas 78229.
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Bhattacharya A, Li K, Quiquand M, Rimesso G, Baker NE. The Notch pathway regulates the Second Mitotic Wave cell cycle independently of bHLH proteins. Dev Biol 2017; 431:309-320. [PMID: 28919436 DOI: 10.1016/j.ydbio.2017.08.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/08/2017] [Accepted: 08/22/2017] [Indexed: 12/31/2022]
Abstract
Notch regulates both neurogenesis and cell cycle activity to coordinate precursor cell generation in the differentiating Drosophila eye. Mosaic analysis with mitotic clones mutant for Notch components was used to identify the pathway of Notch signaling that regulates the cell cycle in the Second Mitotic Wave. Although S phase entry depends on Notch signaling and on the transcription factor Su(H), the transcriptional co-activator Mam and the bHLH repressor genes of the E(spl)-Complex were not essential, although these are Su(H) coactivators and targets during the regulation of neurogenesis. The Second Mitotic Wave showed little dependence on ubiquitin ligases neuralized or mindbomb, and although the ligand Delta is required non-autonomously, partial cell cycle activity occurred in the absence of known Notch ligands. We found that myc was not essential for the Second Mitotic Wave. The Second Mitotic Wave did not require the HLH protein Extra macrochaetae, and the bHLH protein Daughterless was required only cell-nonautonomously. Similar cell cycle phenotypes for Daughterless and Atonal were consistent with requirement for neuronal differentiation to stimulate Delta expression, affecting Notch activity in the Second Mitotic Wave indirectly. Therefore Notch signaling acts to regulate the Second Mitotic Wave without activating bHLH gene targets.
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Affiliation(s)
- Abhishek Bhattacharya
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Ke Li
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Manon Quiquand
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Gerard Rimesso
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Nicholas E Baker
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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10
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Kassis JA, Kennison JA, Tamkun JW. Polycomb and Trithorax Group Genes in Drosophila. Genetics 2017; 206:1699-1725. [PMID: 28778878 PMCID: PMC5560782 DOI: 10.1534/genetics.115.185116] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 05/15/2017] [Indexed: 01/08/2023] Open
Abstract
Polycomb group (PcG) and Trithorax group (TrxG) genes encode important regulators of development and differentiation in metazoans. These two groups of genes were discovered in Drosophila by their opposing effects on homeotic gene (Hox) expression. PcG genes collectively behave as genetic repressors of Hox genes, while the TrxG genes are necessary for HOX gene expression or function. Biochemical studies showed that many PcG proteins are present in two protein complexes, Polycomb repressive complexes 1 and 2, which repress transcription via chromatin modifications. TrxG proteins activate transcription via a variety of mechanisms. Here we summarize the large body of genetic and biochemical experiments in Drosophila on these two important groups of genes.
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Affiliation(s)
- Judith A Kassis
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - James A Kennison
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - John W Tamkun
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, California 95064
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11
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Zaytseva O, Quinn LM. Controlling the Master: Chromatin Dynamics at the MYC Promoter Integrate Developmental Signaling. Genes (Basel) 2017; 8:genes8040118. [PMID: 28398229 PMCID: PMC5406865 DOI: 10.3390/genes8040118] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/15/2017] [Accepted: 04/07/2017] [Indexed: 02/06/2023] Open
Abstract
The transcription factor and cell growth regulator MYC is potently oncogenic and estimated to contribute to most cancers. Decades of attempts to therapeutically target MYC directly have not resulted in feasible clinical applications, and efforts have moved toward indirectly targeting MYC expression, function and/or activity to treat MYC-driven cancer. A multitude of developmental and growth signaling pathways converge on the MYC promoter to modulate transcription through their downstream effectors. Critically, even small increases in MYC abundance (<2 fold) are sufficient to drive overproliferation; however, the details of how oncogenic/growth signaling networks regulate MYC at the level of transcription remain nebulous even during normal development. It is therefore essential to first decipher mechanisms of growth signal-stimulated MYC transcription using in vivo models, with intact signaling environments, to determine exactly how these networks are dysregulated in human cancer. This in turn will provide new modalities and approaches to treat MYC-driven malignancy. Drosophila genetic studies have shed much light on how complex networks signal to transcription factors and enhancers to orchestrate Drosophila MYC (dMYC) transcription, and thus growth and patterning of complex multicellular tissue and organs. This review will discuss the many pathways implicated in patterning MYC transcription during development and the molecular events at the MYC promoter that link signaling to expression. Attention will also be drawn to parallels between mammalian and fly regulation of MYC at the level of transcription.
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Affiliation(s)
- Olga Zaytseva
- ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia.
- School of Biomedical Sciences, University of Melbourne, Parkville 3010, Australia.
| | - Leonie M Quinn
- ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia.
- School of Biomedical Sciences, University of Melbourne, Parkville 3010, Australia.
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12
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Monribot-Villanueva J, Zurita M, Vázquez M. Developmental transcriptional regulation by SUMOylation, an evolving field. Genesis 2017; 55. [PMID: 27935206 DOI: 10.1002/dvg.23009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/29/2016] [Accepted: 11/29/2016] [Indexed: 02/05/2023]
Abstract
SUMOylation is a reversible post-translational protein modification that affects the intracellular localization, stability, activity, and interactions of its protein targets. The SUMOylation pathway influences several nuclear and cytoplasmic processes. The expression of many genes, in particular those involved in development is finely tuned in space and time by several groups of proteins. There is growing evidence that transcriptional regulation mechanisms involve direct SUMOylation of transcriptional-related proteins such as initiation and elongation factors, and subunits of chromatin modifier and remodeling complexes originally described as members of the trithorax and Polycomb groups in Drosophila. Therefore, it is being unveiled that SUMOylation has a role in both, gene silencing and gene activation mechanisms. The goal of this review is to discuss the information on how SUMO modification in components of these multi-subunit complexes may have an effect in genome architecture and function and, therefore, in the regulation of gene expression in time and space.
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Affiliation(s)
- Juan Monribot-Villanueva
- Departamento de Fisiología Molecular y Genética del Desarrollo, Instituto de Biotecnología-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Mario Zurita
- Departamento de Fisiología Molecular y Genética del Desarrollo, Instituto de Biotecnología-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Martha Vázquez
- Departamento de Fisiología Molecular y Genética del Desarrollo, Instituto de Biotecnología-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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Shukla JP, Deshpande G, Shashidhara LS. Ataxin 2-binding protein 1 is a context-specific positive regulator of Notch signaling during neurogenesis in Drosophila melanogaster. Development 2017; 144:905-915. [PMID: 28174239 DOI: 10.1242/dev.140657] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 01/18/2017] [Indexed: 12/28/2022]
Abstract
The role of the Notch pathway during the lateral inhibition that underlies binary cell fate choice is extensively studied, but the context specificity that generates diverse outcomes is less well understood. In the peripheral nervous system of Drosophila melanogaster, differential Notch signaling between cells of the proneural cluster orchestrates sensory organ specification. Here we report functional analysis of Drosophila Ataxin 2-binding protein 1 (A2BP1) during this process. Its human ortholog is linked to type 2 spinocerebellar ataxia and other complex neuronal disorders. Downregulation of Drosophila A2BP1 in the proneural cluster increases adult sensory bristle number, whereas its overexpression results in loss of bristles. We show that A2BP1 regulates sensory organ specification by potentiating Notch signaling. Supporting its direct involvement, biochemical analysis shows that A2BP1 is part of the Suppressor of Hairless [Su(H)] complex in the presence and absence of Notch. However, in the absence of Notch signaling, the A2BP1 interacting fraction of Su(H) does not associate with the repressor proteins Groucho and CtBP. We propose a model explaining the requirement of A2BP1 as a positive regulator of context-specific Notch activity.
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Affiliation(s)
- Jay Prakash Shukla
- Indian Institute of Science Education and Research Pune, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India
| | - Girish Deshpande
- Indian Institute of Science Education and Research Pune, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India.,Department of Molecular Biology, Princeton University, Princeton, NJ 08540, USA
| | - L S Shashidhara
- Indian Institute of Science Education and Research Pune, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India
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14
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Guo L, Zaysteva O, Nie Z, Mitchell NC, Amanda Lee JE, Ware T, Parsons L, Luwor R, Poortinga G, Hannan RD, Levens DL, Quinn LM. Defining the essential function of FBP/KSRP proteins: Drosophila Psi interacts with the mediator complex to modulate MYC transcription and tissue growth. Nucleic Acids Res 2016; 44:7646-58. [PMID: 27207882 PMCID: PMC5027480 DOI: 10.1093/nar/gkw461] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/17/2016] [Indexed: 12/21/2022] Open
Abstract
Despite two decades of research, the major function of FBP-family KH domain proteins during animal development remains controversial. The literature is divided between RNA processing and transcriptional functions for these single stranded nucleic acid binding proteins. Using Drosophila, where the three mammalian FBP proteins (FBP1-3) are represented by one ortholog, Psi, we demonstrate the primary developmental role is control of cell and tissue growth. Co-IP-mass spectrometry positioned Psi in an interactome predominantly comprised of RNA Polymerase II (RNA Pol II) transcriptional machinery and we demonstrate Psi is a potent transcriptional activator. The most striking interaction was between Psi and the transcriptional mediator (MED) complex, a known sensor of signaling inputs. Moreover, genetic manipulation of MED activity modified Psi-dependent growth, which suggests Psi interacts with MED to integrate developmental growth signals. Our data suggest the key target of the Psi/MED network in controlling developmentally regulated tissue growth is the transcription factor MYC. As FBP1 has been implicated in controlling expression of the MYC oncogene, we predict interaction between MED and FBP1 might also have implications for cancer initiation and progression.
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Affiliation(s)
- Linna Guo
- School of Biomedical Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Olga Zaysteva
- School of Biomedical Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Zuqin Nie
- Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Naomi C Mitchell
- School of Biomedical Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jue Er Amanda Lee
- School of Biomedical Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Thomas Ware
- Department of Surgery, University of Melbourne, Royal Melbourne Hospital, Parkville, VIC 3010, Australia
| | - Linda Parsons
- School of Biomedical Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Rodney Luwor
- Department of Surgery, University of Melbourne, Royal Melbourne Hospital, Parkville, VIC 3010, Australia
| | - Gretchen Poortinga
- Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne, VIC 3002, Australia
| | - Ross D Hannan
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Parkville, VIC 3010, Australia Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra City, ACT 2600, Australia
| | - David L Levens
- Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Leonie M Quinn
- School of Biomedical Sciences, University of Melbourne, Parkville, VIC 3010, Australia
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15
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Integration of Orthogonal Signaling by the Notch and Dpp Pathways in Drosophila. Genetics 2016; 203:219-40. [PMID: 26975664 PMCID: PMC4858776 DOI: 10.1534/genetics.116.186791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/08/2016] [Indexed: 11/18/2022] Open
Abstract
The transcription factor Suppressor of Hairless and its coactivator, the Notch intracellular domain, are polyglutamine (pQ)-rich factors that target enhancer elements and interact with other locally bound pQ-rich factors. To understand the functional repertoire of such enhancers, we identify conserved regulatory belts with binding sites for the pQ-rich effectors of both Notch and BMP/Dpp signaling, and the pQ-deficient tissue selectors Apterous (Ap), Scalloped (Sd), and Vestigial (Vg). We find that the densest such binding site cluster in the genome is located in the BMP-inducible nab locus, a homolog of the vertebrate transcriptional cofactors NAB1/NAB2 We report three major findings. First, we find that this nab regulatory belt is a novel enhancer driving dorsal wing margin expression in regions of peak phosphorylated Mad in wing imaginal discs. Second, we show that Ap is developmentally required to license the nab dorsal wing margin enhancer (DWME) to read out Notch and Dpp signaling in the dorsal compartment. Third, we find that the nab DWME is embedded in a complex of intronic enhancers, including a wing quadrant enhancer, a proximal wing disc enhancer, and a larval brain enhancer. This enhancer complex coordinates global nab expression via both tissue-specific activation and interenhancer silencing. We suggest that DWME integration of BMP signaling maintains nab expression in proliferating margin descendants that have divided away from Notch-Delta boundary signaling. As such, uniform expression of genes like nab and vestigial in proliferating compartments would typically require both boundary and nonboundary lineage-specific enhancers.
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16
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Jahan I, Pan N, Elliott KL, Fritzsch B. The quest for restoring hearing: Understanding ear development more completely. Bioessays 2015. [PMID: 26208302 DOI: 10.1002/bies.201500044] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neurosensory hearing loss is a growing problem of super-aged societies. Cochlear implants can restore some hearing, but rebuilding a lost hearing organ would be superior. Research has discovered many cellular and molecular steps to develop a hearing organ but translating those insights into hearing organ restoration remains unclear. For example, we cannot make various hair cell types and arrange them into their specific patterns surrounded by the right type of supporting cells in the right numbers. Our overview of the topologically highly organized and functionally diversified cellular mosaic of the mammalian hearing organ highlights what is known and unknown about its development. Following this analysis, we suggest critical steps to guide future attempts toward restoration of a functional organ of Corti. We argue that generating mutant mouse lines that mimic human pathology to fine-tune attempts toward long-term functional restoration are needed to go beyond the hope generated by restoring single hair cells in postnatal sensory epithelia.
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Affiliation(s)
- Israt Jahan
- Department of Biology, CLAS, University of Iowa, Iowa City, IA, USA
| | - Ning Pan
- Department of Biology, CLAS, University of Iowa, Iowa City, IA, USA
| | - Karen L Elliott
- Department of Biology, CLAS, University of Iowa, Iowa City, IA, USA
| | - Bernd Fritzsch
- Department of Biology, CLAS, University of Iowa, Iowa City, IA, USA
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17
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Clark AD, Oldenbroek M, Boyer TG. Mediator kinase module and human tumorigenesis. Crit Rev Biochem Mol Biol 2015; 50:393-426. [PMID: 26182352 DOI: 10.3109/10409238.2015.1064854] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mediator is a conserved multi-subunit signal processor through which regulatory informatiosn conveyed by gene-specific transcription factors is transduced to RNA Polymerase II (Pol II). In humans, MED13, MED12, CDK8 and Cyclin C (CycC) comprise a four-subunit "kinase" module that exists in variable association with a 26-subunit Mediator core. Genetic and biochemical studies have established the Mediator kinase module as a major ingress of developmental and oncogenic signaling through Mediator, and much of its function in signal-dependent gene regulation derives from its resident CDK8 kinase activity. For example, CDK8-targeted substrate phosphorylation impacts transcription factor half-life, Pol II activity and chromatin chemistry and functional status. Recent structural and biochemical studies have revealed a precise network of physical and functional subunit interactions required for proper kinase module activity. Accordingly, pathologic change in this activity through altered expression or mutation of constituent kinase module subunits can have profound consequences for altered signaling and tumor formation. Herein, we review the structural organization, biological function and oncogenic potential of the Mediator kinase module. We focus principally on tumor-associated alterations in kinase module subunits for which mechanistic relationships as opposed to strictly correlative associations are established. These considerations point to an emerging picture of the Mediator kinase module as an oncogenic unit, one in which pathogenic activation/deactivation through component change drives tumor formation through perturbation of signal-dependent gene regulation. It follows that therapeutic strategies to combat CDK8-driven tumors will involve targeted modulation of CDK8 activity or pharmacologic manipulation of dysregulated CDK8-dependent signaling pathways.
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Affiliation(s)
- Alison D Clark
- a Department of Molecular Medicine , Institute of Biotechnology, University of Texas Health Science Center at San Antonio , San Antonio , TX , USA
| | - Marieke Oldenbroek
- a Department of Molecular Medicine , Institute of Biotechnology, University of Texas Health Science Center at San Antonio , San Antonio , TX , USA
| | - Thomas G Boyer
- a Department of Molecular Medicine , Institute of Biotechnology, University of Texas Health Science Center at San Antonio , San Antonio , TX , USA
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18
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The metazoan-specific mediator subunit 26 (Med26) is essential for viability and is found at both active genes and pericentric heterochromatin in Drosophila melanogaster. Mol Cell Biol 2014; 34:2710-20. [PMID: 24820420 DOI: 10.1128/mcb.01365-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human MED26 was originally purified in the cofactor required for the Sp1 activation complex (CRSP) as a 70-kDa component named CRSP70. This polypeptide was specific to metazoans and the “small” form of the Mediator complex. We report here that a Drosophila melanogaster homologue of MED26 similarly interacts with other components of the core Drosophila Mediator complex but not with the kinase module and is recruited to genes upon activation. Using a null allele of Med26, we show that Med26 is required for organismal viability but not for cell proliferation or survival. Clones lacking Med26 in the wing disc lead to loss of the adult wing margin and reduced expression of genes involved in wing margin formation. Surprisingly, when polytene chromosomes from the salivary gland were examined using antibodies to Med26, it was apparent that a fraction of the protein was associated with the chromocenter, which contains pericentric heterochromatin. This staining colocalizes with heterochromatin protein 1 (HP1). Immunoprecipitation experiments show that Med26 interacts with HP1. The interaction is mediated through the chromoshadow domain of HP1 and through the conserved motif in the carboxy terminus of the Med26 protein. This work is the first characterization of the metazoan-specific Mediator subunit in an animal model.
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19
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Mao F, Yang X, Fu L, Lv X, Zhang Z, Wu W, Yang S, Zhou Z, Zhang L, Zhao Y. The Kto-Skd complex can regulate ptc expression by interacting with Cubitus interruptus (Ci) in the Hedgehog signaling pathway. J Biol Chem 2014; 289:22333-41. [PMID: 24962581 DOI: 10.1074/jbc.m114.560995] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hedgehog (Hh) signaling pathway plays a very important role in metazoan development by controlling pattern formation. Drosophila imaginal discs are subdivided into anterior and posterior compartments that derive from adjacent cell populations. The anterior/posterior (A/P) boundaries, which are critical to maintaining the position of organizers, are established by a complex mechanism involving Hh signaling. Here, we uncover the regulation of ptc in the Hh signaling pathway by two subunits of mediator complex, Kto and Skd, which can also regulate boundary location. Collectively, we provide further evidence that Kto-Skd affects the A/P-axial development of the whole wing disc. Kto can interact with Cubitus interruptus (Ci), bind to the Ci-binding region on ptc promoter, which are both regulated by Hh signals to down-regulate ptc expression.
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Affiliation(s)
- Feifei Mao
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Xiaofeng Yang
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Lin Fu
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Xiangdong Lv
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Zhao Zhang
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Wenqing Wu
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Siqi Yang
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Zhaocai Zhou
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Lei Zhang
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Yun Zhao
- From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
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20
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Kuuluvainen E, Hakala H, Havula E, Sahal Estimé M, Rämet M, Hietakangas V, Mäkelä TP. Cyclin-dependent kinase 8 module expression profiling reveals requirement of mediator subunits 12 and 13 for transcription of Serpent-dependent innate immunity genes in Drosophila. J Biol Chem 2014; 289:16252-61. [PMID: 24778181 DOI: 10.1074/jbc.m113.541904] [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: 12/20/2022] Open
Abstract
The Cdk8 (cyclin-dependent kinase 8) module of Mediator integrates regulatory cues from transcription factors to RNA polymerase II. It consists of four subunits where Med12 and Med13 link Cdk8 and cyclin C (CycC) to core Mediator. Here we have investigated the contributions of the Cdk8 module subunits to transcriptional regulation using RNA interference in Drosophila cells. Genome-wide expression profiling demonstrated separation of Cdk8-CycC and Med12-Med13 profiles. However, transcriptional regulation by Cdk8-CycC was dependent on Med12-Med13. This observation also revealed that Cdk8-CycC and Med12-Med13 often have opposite transcriptional effects. Interestingly, Med12 and Med13 profiles overlapped significantly with that of the GATA factor Serpent. Accordingly, mutational analyses indicated that GATA sites are required for Med12-Med13 regulation of Serpent-dependent genes. Med12 and Med13 were also found to be required for Serpent-activated innate immunity genes in defense to bacterial infection. The results reveal a novel role for the Cdk8 module in Serpent-dependent transcription and innate immunity.
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Affiliation(s)
- Emilia Kuuluvainen
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki
| | - Heini Hakala
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki
| | - Essi Havula
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki, the Department of Biosciences, University of Helsinki, P. O. Box 65, 00014 Helsinki
| | - Michelle Sahal Estimé
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki
| | - Mika Rämet
- the Institute of Biomedical Technology, and BioMediTech, University of Tampere, 33014 Tampere, the Department of Pediatrics, Tampere University Hospital, 22521 Tampere, the Department of Pediatrics, Institute of Clinical Medicine, and Medical Research Center Oulu, University of Oulu, 90014 Oulu, and the Department of Children and Adolescents, Oulu University Hospital, 90029 Oulu, Finland
| | - Ville Hietakangas
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki, the Department of Biosciences, University of Helsinki, P. O. Box 65, 00014 Helsinki
| | - Tomi P Mäkelä
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki,
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Abstract
The Mediator complex is a multi-subunit assembly that appears to be required for regulating expression of most RNA polymerase II (pol II) transcripts, which include protein-coding and most non-coding RNA genes. Mediator and pol II function within the pre-initiation complex (PIC), which consists of Mediator, pol II, TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH and is approximately 4.0 MDa in size. Mediator serves as a central scaffold within the PIC and helps regulate pol II activity in ways that remain poorly understood. Mediator is also generally targeted by sequence-specific, DNA-binding transcription factors (TFs) that work to control gene expression programs in response to developmental or environmental cues. At a basic level, Mediator functions by relaying signals from TFs directly to the pol II enzyme, thereby facilitating TF-dependent regulation of gene expression. Thus, Mediator is essential for converting biological inputs (communicated by TFs) to physiological responses (via changes in gene expression). In this review, we summarize an expansive body of research on the Mediator complex, with an emphasis on yeast and mammalian complexes. We focus on the basics that underlie Mediator function, such as its structure and subunit composition, and describe its broad regulatory influence on gene expression, ranging from chromatin architecture to transcription initiation and elongation, to mRNA processing. We also describe factors that influence Mediator structure and activity, including TFs, non-coding RNAs and the CDK8 module.
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Affiliation(s)
- Zachary C Poss
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, CO , USA
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22
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Asadollahi R, Oneda B, Sheth F, Azzarello-Burri S, Baldinger R, Joset P, Latal B, Knirsch W, Desai S, Baumer A, Houge G, Andrieux J, Rauch A. Dosage changes of MED13L further delineate its role in congenital heart defects and intellectual disability. Eur J Hum Genet 2013; 21:1100-4. [PMID: 23403903 DOI: 10.1038/ejhg.2013.17] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/09/2013] [Accepted: 01/16/2013] [Indexed: 01/20/2023] Open
Abstract
A chromosomal balanced translocation disrupting the MED13L (Mediator complex subunit13-like) gene, encoding a subunit of the Mediator complex, was previously associated with transposition of the great arteries (TGA) and intellectual disability (ID), and led to the identification of missense mutations in three patients with isolated TGA. Recently, a homozygous missense mutation in MED13L was found in two siblings with non-syndromic ID from a consanguineous family. Here, we describe for the first time, three patients with copy number changes affecting MED13L and delineate a recognizable MED13L haploinsufficiency syndrome. Using high resolution molecular karyotyping, we identified two intragenic de novo frameshift deletions, likely resulting in haploinsufficiency, in two patients with a similar phenotype of hypotonia, moderate ID, conotruncal heart defect and facial anomalies. In both, Sanger sequencing of MED13L did not reveal any pathogenic mutation and exome sequencing in one patient showed no evidence for a non-allelic second hit. A further patient with hypotonia, learning difficulties and perimembranous VSD showed a 1 Mb de novo triplication in 12q24.2, including MED13L and MAP1LC3B2. Our findings show that MED13L haploinsufficiency in contrast to the previously observed missense mutations cause a distinct syndromic phenotype. Additionally, a MED13L copy number gain results in a milder phenotype. The clinical features suggesting a neurocristopathy may be explained by animal model studies indicating involvement of the Mediator complex subunit 13 in neural crest induction.
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Affiliation(s)
- Reza Asadollahi
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
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