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Bamaga A, Muthaffar O, Alyazidi A, Bahowarth S, Shawli M, Alotibi F, Alsehemi M, Almohammal M, Alawwadh A, Alghamdi N. MED23 pathogenic variant: genomic-phenotypic analysis. J Med Life 2024; 17:500-507. [PMID: 39144687 PMCID: PMC11320618 DOI: 10.25122/jml-2024-0065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/02/2024] [Indexed: 08/16/2024] Open
Abstract
The mediator complex subunit 23 (MED23) gene encodes a protein that acts as a tail module mediator complex, a multi-subunit co-activator involved in several cellular activities. MED23 has been shown to have substantial roles in myogenesis and other molecular mechanisms. The functions of MED23 in the neurological system remain unclear and the clinical phenotype is not thoroughly described. Whole exome sequencing was used to identify a novel mutation in the MED23 gene. DNA capture probes using next-generation sequencing-based copy number variation analysis with Illumina array were performed. The clinical, demographic, neuroimaging, and electrophysiological data of the patients were collected, and similarly, the data of all reported cases in the literature were extracted to compare findings. Screening a total of 9,662 articles, we identified 22 main regulatory processes for the MED23 gene, including suppressive activity for carcinogenic processes. MED23 is also involved in the brain's neurogenesis and functions. The identified cases mainly presented with intellectual disability (87.5%) and developmental delay (50%). Seizures were present in only 18.75% of the patients. Slow backgrounds and spike and sharp-wave complexes were reported on the electroencephalogram (EEG) of a few patients and delayed myelination, thin corpus callosum, and pontine hypoplasia on magnetic resonance imaging (MRI). The MED23 gene regulates several processes in which its understanding promotes considerable therapeutic potential for patients. It is crucial to consider genetic and laboratory testing, particularly when encountering potential carriers. Intellectual disability and developmental delay are the most notable clinical signs with heterogeneous features on EEG and MRI.
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Affiliation(s)
- Ahmed Bamaga
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Neuromuscular Medicine Unit, Department of Pediatrics, Faculty of Medicine, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Osama Muthaffar
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Anas Alyazidi
- Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sarah Bahowarth
- Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammed Shawli
- Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Fahad Alotibi
- Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Matar Alsehemi
- Pediatric Neurology Unit, Department of Pediatrics, King Fahad Hospital, Albaha, Saudi Arabia
| | | | - Adel Alawwadh
- Department of Pediatrics, Khamis Mushait Maternity and Children Hospital, Abha, Saudi Arabia
| | - Njood Alghamdi
- Faculty of Medicine, Albaha University, Albaha, Saudi Arabia
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2
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Yang JH, Liu ZG, Liu CL, Zhang MR, Jia YL, Zhai QX, He MF, He N, Qiao JD. MED12 variants associated with X-linked recessive partial epilepsy without intellectual disability. Seizure 2024; 116:30-36. [PMID: 36894399 DOI: 10.1016/j.seizure.2023.02.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
OBJECTIVES The MED12 gene encodes mediator complex subunit 12, which is a component of the mediator complex involved in the transcriptional regulation of nearly all RNA polymerase II-dependent genes. MED12 variants have previously been associated with developmental disorders with or without nonspecific intellectual disability. This study aims to explore the association between MED12 variants and epilepsy. MATERIALS AND METHODS Trios-based whole-exome sequencing was performed in a cohort of 349 unrelated cases with partial (focal) epilepsy without acquired causes. The genotype-phenotype correlations of MED12 variants were analyzed. RESULTS Five hemizygous missense MED12 variants, including c.958A>G/p.Ile320Val, c.1757G>A/p.Ser586Asn, c.2138C>T/p.Pro713Leu, c.3379T>C/p.Ser1127Pro, and c.4219A>C/p.Met1407Leu were identified in five unrelated males with partial epilepsy. All patients showed infrequent focal seizures and achieved seizure free without developmental abnormalities or intellectual disability. All the hemizygous variants were inherited from asymptomatic mothers (consistent with the X-linked recessive inheritance pattern) and were absent in the general population. The two variants with damaging hydrogen bonds were associated with early-onset seizures. Further genotype-phenotype analysis revealed that congenital anomaly disorder (Hardikar syndrome) was associated with (de novo) destructive variants in an X-linked dominant inheritance pattern, whereas epilepsy was associated with missense variants in an X-linked recessive inheritance pattern. Phenotypic features of intellectual disability appeared as the intermediate phenotype in terms of both genotype and inheritance. Epilepsy-related variants were located at the MED12-LCEWAV domain and the regions between MED12-LCEWAV and MED12-POL. CONCLUSION MED12 is a potentially causative gene for X-linked recessive partial epilepsy without developmental or intellectual abnormalities. The genotype-phenotype correlation of MED12 variants explains the phenotypic variations and can help the genetic diagnosis.
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Affiliation(s)
- Jie-Hua Yang
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China; Department of Neurology, the Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Zhi-Gang Liu
- Department of Pediatrics, Affiliated Foshan Maternity & Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong, China
| | - Chun-Ling Liu
- Department of Neurology, the Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Ming-Rui Zhang
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yan-Lu Jia
- Department of Neurology, the Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Qiong-Xiang Zhai
- Department of pediatrics, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Ming-Feng He
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Na He
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.
| | - Jing-Da Qiao
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.
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3
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Abstract
Enhancers are cis-regulatory elements that can stimulate gene expression from distance, and drive precise spatiotemporal gene expression profiles during development. Functional enhancers display specific features including an open chromatin conformation, Histone H3 lysine 27 acetylation, Histone H3 lysine 4 mono-methylation enrichment, and enhancer RNAs production. These features are modified upon developmental cues which impacts their activity. In this review, we describe the current state of knowledge about enhancer functions and the diverse chromatin signatures found on enhancers. We also discuss the dynamic changes of enhancer chromatin signatures, and their impact on lineage specific gene expression profiles, during development or cellular differentiation.
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Affiliation(s)
- Amandine Barral
- Institute for Regenerative Medicine, Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA,CONTACT Amandine Barral Institute for Regenerative Medicine, Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania. 3400 Civic Blvd, Philadelphia, Pennsylvania19104, USA
| | - Jérôme Déjardin
- Biology of repetitive sequences, Institute of Human Genetics CNRS-Université de Montpellier UMR 9002, Montpellier, France,Jérôme Déjardin Biology of repetitive sequences, Institute of Human Genetics CNRS-Université de Montpellier UMR 9002, 141 rue de la Cardonille, Montpellier34000, France
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4
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Malik S, Roeder RG. Regulation of the RNA polymerase II pre-initiation complex by its associated coactivators. Nat Rev Genet 2023; 24:767-782. [PMID: 37532915 PMCID: PMC11088444 DOI: 10.1038/s41576-023-00630-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2023] [Indexed: 08/04/2023]
Abstract
The RNA polymerase II (Pol II) pre-initiation complex (PIC) is a critical node in eukaryotic transcription regulation, and its formation is the major rate-limiting step in transcriptional activation. Diverse cellular signals borne by transcriptional activators converge on this large, multiprotein assembly and are transduced via intermediary factors termed coactivators. Cryogenic electron microscopy, multi-omics and single-molecule approaches have recently offered unprecedented insights into both the structure and cellular functions of the PIC and two key PIC-associated coactivators, Mediator and TFIID. Here, we review advances in our understanding of how Mediator and TFIID interact with activators and affect PIC formation and function. We also discuss how their functions are influenced by their chromatin environment and selected cofactors. We consider how, through its multifarious interactions and functionalities, a Mediator-containing and TFIID-containing PIC can yield an integrated signal processing system with the flexibility to determine the unique temporal and spatial expression pattern of a given gene.
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Affiliation(s)
- Sohail Malik
- Laboratory of Biochemistry & Molecular Biology, The Rockefeller University, New York, NY, USA.
| | - Robert G Roeder
- Laboratory of Biochemistry & Molecular Biology, The Rockefeller University, New York, NY, USA
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5
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Arif MAR, Tripodi P, Waheed MQ, Afzal I, Pistrick S, Schütze G, Börner A. Genetic Analyses of Seed Longevity in Capsicum annuum L. in Cold Storage Conditions. PLANTS (BASEL, SWITZERLAND) 2023; 12:1321. [PMID: 36987009 PMCID: PMC10057624 DOI: 10.3390/plants12061321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/06/2023] [Accepted: 03/13/2023] [Indexed: 06/19/2023]
Abstract
Seed longevity is the most important trait in the genebank management system. No seed can remain infinitely viable. There are 1241 accessions of Capsicum annuum L. available at the German Federal ex situ genebank at IPK Gatersleben. C. annuum (Capsicum) is the most economically important species of the genus Capsicum. So far, there is no report that has addressed the genetic basis of seed longevity in Capsicum. Here, we convened a total of 1152 Capsicum accessions that were deposited in Gatersleben over forty years (from 1976 to 2017) and assessed their longevity by analyzing the standard germination percentage after 5-40 years of storage at -15/-18 °C. These data were used to determine the genetic causes of seed longevity, along with 23,462 single nucleotide polymorphism (SNP) markers covering all of the 12 Capsicum chromosomes. Using the association-mapping approach, we identified a total of 224 marker trait associations (MTAs) (34, 25, 31, 35, 39, 7, 21 and 32 MTAs after 5-, 10-, 15-, 20-, 25-, 30-, 35- and 40-year storage intervals) on all the Capsicum chromosomes. Several candidate genes were identified using the blast analysis of SNPs, and these candidate genes are discussed.
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Affiliation(s)
| | - Pasquale Tripodi
- Research Centre for Vegetable and Ornamental Crops, Council for Agricultural Research and Economics (CREA), 84098 Pontecagnano Faiano, Italy
| | | | - Irfan Afzal
- Seed Physiology Lab, Department of Agronomy, University of Agriculture, Faisalabad 38000, Pakistan
| | - Sibylle Pistrick
- Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstr. 3, 06466 Seeland, Germany
| | - Gudrun Schütze
- Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstr. 3, 06466 Seeland, Germany
| | - Andreas Börner
- Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstr. 3, 06466 Seeland, Germany
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6
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Salzano E, Niceta M, Pizzi S, Radio FC, Busè M, Mercadante F, Barresi S, Ferrara A, Mancini C, Tartaglia M, Piccione M. Case report: Novel compound heterozygosity for pathogenic variants in MED23 in a syndromic patient with postnatal microcephaly. Front Neurol 2023; 14:1090082. [PMID: 36824420 PMCID: PMC9941528 DOI: 10.3389/fneur.2023.1090082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/11/2023] [Indexed: 02/10/2023] Open
Abstract
Biallelic loss-of-function variants in MED23 cause a recessive syndromic intellectual disability condition with or without epilepsy (MRT18). Due to the small number of reported individuals, the clinical phenotype of the disorder has not been fully delineated yet, and the spectrum and frequency of neurologic features have not been fully characterized. Here, we report a 5-year-old girl with compound heterozygous for two additional MED23 variants. Besides global developmental delay, axial hypotonia and peripheral increased muscular tone, absent speech, and generalized tonic seizures, which fit well MRT18, the occurrence of postnatal progressive microcephaly has been here documented. A retrospective assessment of the previously reported clinical data for these subjects confirms the occurrence of postnatal progressive microcephaly as a previously unappreciated feature of the phenotype of MED23-related disorder.
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Affiliation(s)
- Emanuela Salzano
- Medical Genetics Unit, AOOR Villa Sofia-Cervello Hospitals, Palermo, Italy,*Correspondence: Emanuela Salzano ✉
| | - Marcello Niceta
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Simone Pizzi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | | | - Martina Busè
- Medical Genetics Unit, AOOR Villa Sofia-Cervello Hospitals, Palermo, Italy
| | | | - Sabina Barresi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Arturo Ferrara
- Medical Genetics Unit, AOOR Villa Sofia-Cervello Hospitals, Palermo, Italy
| | - Cecilia Mancini
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Maria Piccione
- Medical Genetics Unit, AOOR Villa Sofia-Cervello Hospitals, Palermo, Italy,Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
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7
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Lambert É, Puwakdandawa K, Tao YF, Robert F. From structure to molecular condensates: emerging mechanisms for Mediator function. FEBS J 2023; 290:286-309. [PMID: 34698446 DOI: 10.1111/febs.16250] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/15/2021] [Accepted: 10/25/2021] [Indexed: 02/05/2023]
Abstract
Mediator is a large modular protein assembly whose function as a coactivator of transcription is conserved in all eukaryotes. The Mediator complex can integrate and relay signals from gene-specific activators bound at enhancers to activate the general transcription machinery located at promoters. It has thus been described as a bridge between these elements during initiation of transcription. Here, we review recent studies on Mediator relating to its structure, gene specificity and general requirement, roles in chromatin architecture as well as novel concepts involving phase separation and transcriptional bursting. We revisit the mechanism of action of Mediator and ultimately put forward models for its mode of action in gene activation.
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Affiliation(s)
- Élie Lambert
- Institut de recherches cliniques de Montréal, Canada
| | | | - Yi Fei Tao
- Institut de recherches cliniques de Montréal, Canada
| | - François Robert
- Institut de recherches cliniques de Montréal, Canada.,Département de Médecine, Faculté de Médecine, Université de Montréal, Canada
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8
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Warfield L, Donczew R, Mahendrawada L, Hahn S. Yeast Mediator facilitates transcription initiation at most promoters via a Tail-independent mechanism. Mol Cell 2022; 82:4033-4048.e7. [PMID: 36208626 PMCID: PMC9637718 DOI: 10.1016/j.molcel.2022.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 05/12/2022] [Accepted: 09/13/2022] [Indexed: 11/06/2022]
Abstract
Mediator (MED) is a conserved factor with important roles in basal and activated transcription. Here, we investigate the genome-wide roles of yeast MED by rapid depletion of its activator-binding domain (Tail) and monitoring changes in nascent transcription. Rapid Tail depletion surprisingly reduces transcription from only a small subset of genes. At most of these Tail-dependent genes, in unperturbed conditions, MED is detected at both the UASs and promoters. In contrast, at most Tail-independent genes, we find MED primarily at promoters but not at the UASs. These results suggest that MED Tail and activator-mediated MED recruitment regulates only a small subset of genes. Furthermore, we define three classes of genes that differ in PIC assembly pathways and the requirements for MED Tail, SAGA, TFIID, and BET factors Bdf1/2. Our combined results have broad implications for the roles of MED, other coactivators, and mechanisms of transcriptional regulation at different gene classes.
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Affiliation(s)
- Linda Warfield
- Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Mailstop A1-162, Seattle, WA 98109, USA
| | - Rafal Donczew
- Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Mailstop A1-162, Seattle, WA 98109, USA
| | - Lakshmi Mahendrawada
- Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Mailstop A1-162, Seattle, WA 98109, USA
| | - Steven Hahn
- Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Mailstop A1-162, Seattle, WA 98109, USA.
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9
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Takao T, Ono M, Yoshimasa Y, Masuda H, Maruyama T. A mediator complex subunit 12 gain-of-function mutation induces partial leiomyoma cell properties in human uterine smooth muscle cells. F&S SCIENCE 2022; 3:288-298. [PMID: 35643626 DOI: 10.1016/j.xfss.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/18/2022] [Accepted: 04/12/2022] [Indexed: 06/15/2023]
Abstract
OBJECTIVE To clarify whether a mediator complex subunit 12 (MED12) gain-of-function mutation induces leiomyoma cell properties in human uterine smooth muscle cells (USMCs). DESIGN Experimental study. SETTING Academic research laboratory. PATIENT(S) Women undergoing hysterectomy for leiomyoma. INTERVENTION(S) CRISPR/Cas9-mediated genome editing to introduce an MED12 gain-of-function mutation (G44D) into human USMCs. MAIN OUTCOME MEASURE(S) Cell proliferation, collagen production, and in vivo tumorigenicity of USMCs with vs. without the MED12 mutation. RESULT(S) Uterine smooth muscle cells isolated from the uterine myometrium of a 44-year-old patient were subjected to lentiviral vector-mediated gene transduction of the fluorescent protein Venus, followed by long-term passage. Uterine smooth muscle cells with a normal female karyotype, high cell proliferative activity, and Venus expression, but without stem/progenitor cell populations, were obtained and designated as USMC44. Using CRISPR/Cas9-mediated genome editing, mtUSMC44 (MED12, 131G>A, p.G44D) and mock USMC44 without MED12 mutation (wtUSMC44) were established from USMC44. wtUSMC44 and mtUSMC44 showed similar cell proliferation activity, even in the presence of estradiol and progesterone (EP) together with transforming growth factor-beta 3 (TGFB3). In addition, wtUSMC44 and mtUSMC44 generated similar tiny smooth muscle-like tissue constructs when xenotransplanted beneath the kidney capsule in immunodeficient mice treated with EP alone or TGFB3. In contrast, mtUSMC44 produced more collagen type I than wtUSMC in vitro, and this production was likely enhanced by EP and TGFB3. CONCLUSION(S) The results suggest that the MED12 gain-of-function mutation is involved in collagen production. Although approximately 70% of leiomyomas have MED12 mutations, additional factors and/or events other than MED12 and/or myometrial stem/progenitor cells may be required for fully inducing leiomyoma cell properties, including transformation, in USMCs.
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Affiliation(s)
- Tomoka Takao
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan; Department of Regenerative Science, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Masanori Ono
- Department of Obstetrics and Gynecology, Tokyo Medical University, Tokyo, Japan
| | - Yushi Yoshimasa
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Hirotaka Masuda
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Tetsuo Maruyama
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan.
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10
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Rojas DA, Urbina F, Valenzuela-Pérez L, Leiva L, Miralles VJ, Maldonado E. Initiator-Directed Transcription: Fission Yeast Nmtl Initiator Directs Preinitiation Complex Formation and Transcriptional Initiation. Genes (Basel) 2022; 13:genes13020256. [PMID: 35205301 PMCID: PMC8871863 DOI: 10.3390/genes13020256] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/22/2022] [Accepted: 01/25/2022] [Indexed: 02/01/2023] Open
Abstract
The initiator element is a core promoter element encompassing the transcription start site, which is found in yeast, Drosophila, and human promoters. This element is observed in TATA-less promoters. Several studies have defined transcription factor requirements and additional cofactors that are needed for transcription initiation of initiator-containing promoters. However, those studies have been performed with additional core promoters in addition to the initiator. In this work, we have defined the pathway of preinitiation complex formation on the fission yeast nmt1 gene promoter, which contains a functional initiator with striking similarity to the initiator of the human dihydrofolate reductase (hDHFR) gene and to the factor requirement for transcription initiation of the nmt1 gene promoter. The results show that the nmt1 gene promoter possesses an initiator encompassing the transcription start site, and several conserved base positions are required for initiator function. A preinitiation complex formation on the nmt1 initiator can be started by TBP/TFIIA or TBP/TFIIB, but not TBP alone, and afterwards follows the same pathway as preinitiation complex formation on TATA-containing promoters. Transcription initiation is dependent on the general transcription factors TBP, TFIIB, TFIIE, TFIIF, TFIIH, RNA polymerase II, Mediator, and a cofactor identified as transcription cofactor for initiator function (TCIF), which is a high-molecular-weight protein complex of around 500 kDa. However, the TAF subunits of TFIID were not required for the nmt1 initiator transcription, as far as we tested. We also demonstrate that other initiators of the nmt1/hDHFR family can be transcribed in fission yeast whole-cell extracts.
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Affiliation(s)
- Diego A. Rojas
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago 8910132, Chile
- Correspondence: address: (D.A.R.); (E.M.)
| | - Fabiola Urbina
- Programa de Biología Celular y Molecular, ICBM, Facultad de Medicina, Universidad de Chile, Santiago 8380492, Chile; (F.U.); (L.V.-P.); (L.L.)
| | - Lucía Valenzuela-Pérez
- Programa de Biología Celular y Molecular, ICBM, Facultad de Medicina, Universidad de Chile, Santiago 8380492, Chile; (F.U.); (L.V.-P.); (L.L.)
| | - Lorenzo Leiva
- Programa de Biología Celular y Molecular, ICBM, Facultad de Medicina, Universidad de Chile, Santiago 8380492, Chile; (F.U.); (L.V.-P.); (L.L.)
| | - Vicente J. Miralles
- Departamento Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Valencia, 46010 Valencia, Spain;
| | - Edio Maldonado
- Programa de Biología Celular y Molecular, ICBM, Facultad de Medicina, Universidad de Chile, Santiago 8380492, Chile; (F.U.); (L.V.-P.); (L.L.)
- Correspondence: address: (D.A.R.); (E.M.)
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11
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Firdaus R, Agrawal P, Anagani M, Vijayalakshmi K, Hasan Q. Multiple Mutations in Exon-2 of Med-12 Identified in Uterine Leiomyomata. J Reprod Infertil 2021; 22:201-209. [PMID: 34900640 PMCID: PMC8607871 DOI: 10.18502/jri.v22i3.6720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/20/2020] [Indexed: 11/24/2022] Open
Abstract
Background: Uterine leiomyomata (UL), commonly known as uterine fibroids, are benign smooth muscle tumors of the myometrium. They cause pelvic pain, abnormal uterine bleeding, and infertility in women of reproductive age. The ovarian hormone estrogen is the main stimulator for the fibroid growth. The etiology is not yet clearly understood; however, UL are believed to be monoclonal tumors arising from a common progenitor cell. Chromosomal cytogenetic abnormalities have been demonstrated in 40–50% of the fibroids. The most frequent tumor specific genetic alterations in UL were identified in exon-2 of Mediator Complex Subunit 12 (MED-12). Methods: In the present study, twenty-two multiple fibroids were evaluated both from the same uterus and from different uteri, of four women, for somatic mutations in hotspot region of MED-12. The tissue DNA of the UL’s was isolated, amplified by PCR visualized on gel and sent for Sanger sequencing. Results: The results indicate several variants in exon-2 and flanking intronic regions, seven exonic variants and five intronic variants which provide evidence that multiple UL in the same uterus may not be clonal in origin. Conclusion: This study indicates genetic heterogeneity. UL may not have a clonal origin, these exon-2 variants of MED-12 gene could be involved in UL progression.
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Affiliation(s)
- Ruqia Firdaus
- Department of Genetics and Molecular Medicine, Vasavi Medical and Research Center, Lakdi-ka-pool, Hyderabad, India.,Department of Biotechnology, Hyderabad Science Society, Hyderabad, India.,Department of Genetics, Osmania University, Hyderabad, India
| | - Prabha Agrawal
- Department of Gynaecology and Obstetrics, Medicover Hospitals, Hi-Tech City, Hyderabad, India
| | - Manjula Anagani
- Department of Gynaecology and Obstetrics, Medicover Hospitals, Hi-Tech City, Hyderabad, India
| | - Kodati Vijayalakshmi
- Department of Genetics and Molecular Medicine, Vasavi Medical and Research Center, Lakdi-ka-pool, Hyderabad, India.,Department of Genetics, Osmania University, Hyderabad, India
| | - Qurratulain Hasan
- Department of Biotechnology, Hyderabad Science Society, Hyderabad, India.,Department of Genetics, Osmania University, Hyderabad, India.,Department of Genetics and Molecular Medicine, Kamineni Hospital, LB Nagar, Hyderabad, India
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12
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Nguyen VQ, Ranjan A, Liu S, Tang X, Ling YH, Wisniewski J, Mizuguchi G, Li KY, Jou V, Zheng Q, Lavis LD, Lionnet T, Wu C. Spatiotemporal coordination of transcription preinitiation complex assembly in live cells. Mol Cell 2021; 81:3560-3575.e6. [PMID: 34375585 PMCID: PMC8420877 DOI: 10.1016/j.molcel.2021.07.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/18/2021] [Accepted: 07/16/2021] [Indexed: 12/17/2022]
Abstract
Transcription initiation by RNA polymerase II (RNA Pol II) requires preinitiation complex (PIC) assembly at gene promoters. In the dynamic nucleus, where thousands of promoters are broadly distributed in chromatin, it is unclear how multiple individual components converge on any target to establish the PIC. Here we use live-cell, single-molecule tracking in S. cerevisiae to visualize constrained exploration of the nucleoplasm by PIC components and Mediator's key role in guiding this process. On chromatin, TFIID/TATA-binding protein (TBP), Mediator, and RNA Pol II instruct assembly of a short-lived PIC, which occurs infrequently but efficiently within a few seconds on average. Moreover, PIC exclusion by nucleosome encroachment underscores regulated promoter accessibility by chromatin remodeling. Thus, coordinated nuclear exploration and recruitment to accessible targets underlies dynamic PIC establishment in yeast. Our study provides a global spatiotemporal model for transcription initiation in live cells.
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Affiliation(s)
- Vu Q Nguyen
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Anand Ranjan
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sheng Liu
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xiaona Tang
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Yick Hin Ling
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jan Wisniewski
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Experimental Immunology Branch, National Cancer Institute, Bethesda, MD 20892, USA
| | - Gaku Mizuguchi
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Kai Yu Li
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Vivian Jou
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Qinsi Zheng
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Timothée Lionnet
- Institute of Systems Genetics, Langone Medical Center, New York University, New York, NY 10016, USA
| | - Carl Wu
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Molecular Biology and Genetics, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
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13
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An S, Kim G, Kim HJ, Ahn S, Kim HY, Ko H, Hyun YE, Nguyen M, Jeong J, Liu Z, Han J, Choi H, Yu J, Kim JW, Lee HW, Jacobson KA, Cho WJ, Kim YM, Kang KW, Noh M, Jeong LS. Discovery and Structure-Activity Relationships of Novel Template, Truncated 1'-Homologated Adenosine Derivatives as Pure Dual PPARγ/δ Modulators. J Med Chem 2020; 63:16012-16027. [PMID: 33325691 DOI: 10.1021/acs.jmedchem.0c01874] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Following our report that A3 adenosine receptor (AR) antagonist 1 exhibited a polypharmacological profile as a dual modulator of peroxisome proliferator-activated receptor (PPAR)γ/δ, we discovered a new template, 1'-homologated adenosine analogues 4a-4t, as dual PPARγ/δ modulators without AR binding. Removal of binding affinity to A3AR was achieved by 1'-homologation, and PPARγ/δ dual modulation was derived from the structural similarity between the target nucleosides and PPAR modulator drug, rosiglitazone. All the final nucleosides were devoid of AR-binding affinity and exhibited high binding affinities to PPARγ/δ but lacked PPARα binding. 2-Cl derivatives exhibited dual receptor-binding affinity to PPARγ/δ, which was absent for the corresponding 2-H derivatives. 2-Propynyl substitution prevented PPARδ-binding affinity but preserved PPARγ affinity, indicating that the C2 position defines a pharmacophore for selective PPARγ ligand designs. PPARγ/δ dual modulators functioning as both PPARγ partial agonists and PPARδ antagonists promoted adiponectin production, suggesting their therapeutic potential against hypoadiponectinemia-associated cancer and metabolic diseases.
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Affiliation(s)
- Seungchan An
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea.,Natural Products Research Institute, Seoul National University, Seoul 08826, Korea
| | - Gyudong Kim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea.,College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Gwangju 61186, Korea
| | - Hyun Jin Kim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Sungjin Ahn
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea.,Natural Products Research Institute, Seoul National University, Seoul 08826, Korea
| | - Hyun Young Kim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Hyejin Ko
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea.,Natural Products Research Institute, Seoul National University, Seoul 08826, Korea
| | - Young Eum Hyun
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Mai Nguyen
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea.,College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Gwangju 61186, Korea
| | - Juri Jeong
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea.,College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Gwangju 61186, Korea
| | - Zijing Liu
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea.,College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Gwangju 61186, Korea
| | - Jinhe Han
- College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Gwangju 61186, Korea
| | - Hongseok Choi
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Jinha Yu
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Ji Won Kim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Hyuk Woo Lee
- Future Medicine Company Ltd., Seongnam, Gyeonggi-do 13449, Korea
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Disease, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Won Jea Cho
- College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Gwangju 61186, Korea
| | - Young-Mi Kim
- Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Korea
| | - Keon Wook Kang
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Minsoo Noh
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea.,Natural Products Research Institute, Seoul National University, Seoul 08826, Korea
| | - Lak Shin Jeong
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
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14
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Al-Husini N, Medler S, Ansari A. Crosstalk of promoter and terminator during RNA polymerase II transcription cycle. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194657. [PMID: 33246184 DOI: 10.1016/j.bbagrm.2020.194657] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 12/16/2022]
Abstract
The transcription cycle of RNAPII is comprised of three consecutive steps; initiation, elongation and termination. It has been assumed that the initiation and termination steps occur in spatial isolation, essentially as independent events. A growing body of evidence, however, has challenged this dogma. First, factors involved in initiation and termination exhibit both a genetic and a physical interaction during transcription. Second, the initiation and termination factors have been found to occupy both ends of a transcribing gene. Third, physical interaction of initiation and termination factors occupying distal ends of a gene sometime results in the entire terminator region of a genes looping back and contact its cognate promoter, thereby forming a looped gene architecture during transcription. A logical interpretation of these findings is that the initiation and termination steps of transcription do not occur in isolation. There is extensive communication of factors occupying promoter and terminator ends of a gene during transcription cycle. This review entails a discussion of the promoter-terminator crosstalk and its implication in the context of transcription.
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Affiliation(s)
- Nadra Al-Husini
- Department of Biological Science, Wayne State University, Detroit, MI, United States of America
| | - Scott Medler
- Department of Biological Science, Wayne State University, Detroit, MI, United States of America
| | - Athar Ansari
- Department of Biological Science, Wayne State University, Detroit, MI, United States of America.
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15
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Wu D, Zhang Z, Chen X, Yan Y, Liu X. Angel or Devil ? - CDK8 as the new drug target. Eur J Med Chem 2020; 213:113043. [PMID: 33257171 DOI: 10.1016/j.ejmech.2020.113043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022]
Abstract
Cyclin-dependent kinase 8 (CDK8) plays an momentous role in transcription regulation by forming kinase module or transcription factor phosphorylation. A large number of evidences have identified CDK8 as an important factor in cancer occurrence and development. In addition, CDK8 also participates in the regulation of cancer cell stress response to radiotherapy and chemotherapy, assists tumor cell invasion, metastasis, and drug resistance. Therefore, CDK8 is regarded as a promising target for cancer therapy. Most studies in recent years supported the role of CDK8 as a carcinogen, however, under certain conditions, CDK8 exists as a tumor suppressor. The functional diversity of CDK8 and its exceptional role in different types of cancer have aroused great interest from scientists but even more controversy during the discovery of CDK8 inhibitors. In addition, CDK8 appears to be an effective target for inflammation diseases and immune system disorders. Therefore, we summarized the research results of CDK8, involving physiological/pathogenic mechanisms and the development status of compounds targeting CDK8, provide a reference for the feasibility evaluation of CDK8 as a therapeutic target, and guidance for researchers who are involved in this field for the first time.
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Affiliation(s)
- Dan Wu
- School of Biological Engineering, Hefei Technology College, Hefei, 238000, PR China
| | - Zhaoyan Zhang
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, 230032, PR China
| | - Xing Chen
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, 230032, PR China
| | - Yaoyao Yan
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, 230032, PR China
| | - Xinhua Liu
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, 230032, PR China.
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16
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Development of an MS Workflow Based on Combining Database Search Engines for Accurate Protein Identification and Its Validation to Identify the Serum Proteomic Profile in Female Stress Urinary Incontinence. BIOMED RESEARCH INTERNATIONAL 2020. [DOI: 10.1155/2020/8740468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A critical stage of shotgun proteomics is database search, a process which attempts to match the experimental spectra to the theoretical one. Given the considerable time and effort spent in analysis, it is self-evident for a researcher to aspire for rigorous computational analysis and a more confident and accurate peptide/protein identification. Mass spectrometry (MS) has been applied across several clinical disciplines. The pathophysiology of Stress Urinary Incontinence (SUI), caused by a damaged pelvic floor, has become a boundless disease altering the quality of life worldwide. Although some studies pointed markers that can be bioindicators for SUI, these findings raise the issue of sensitivity and specificity. Therefore, it is critical to have a sensitive and specific analytical approach to identify markers that have been associated with protective and deleterious associations in disease. Here, we describe our designed and developed workflow for protein identification from tandem mass spectrometry that uses multiple search engines. We apply our workflow to an existing study addressing the pathophysiology of SUI. We demonstrate how using the combined approach together with high-performance computing techniques can surmount the challenges of complex analyses and extended computing time. We also compare the relative performance of each combination. Our results suggest that a combination of MS-GF+ and COMET represents the best sensitivity-specificity trade-off, outperforming all other tested combinations. The approach was also sensitive and accurately identified a set of protein that was shown to be markers for categories of diseases associated with the pathophysiology of SUI. This workflow was developed to encourage proteomic researchers to adopt MS-based techniques for accurate analysis and to promote MS as a routine tool to the clinical cohorts.
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17
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Nath VS, Shrestha A, Awasthi P, Mishra AK, Kocábek T, Matoušek J, Sečnik A, Jakše J, Radišek S, Hallan V. Mapping the Gene Expression Spectrum of Mediator Subunits in Response to Viroid Infection in Plants. Int J Mol Sci 2020; 21:E2498. [PMID: 32260277 PMCID: PMC7177877 DOI: 10.3390/ijms21072498] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 12/25/2022] Open
Abstract
The mediator (MED) represents a large, conserved, multi-subunit protein complex that regulates gene expression through interactions with RNA polymerase II and enhancer-bound transcription factors. Expanding research accomplishments suggest the predominant role of plant MED subunits in the regulation of various physiological and developmental processes, including the biotic stress response against bacterial and fungal pathogens. However, the involvement of MED subunits in virus/viroid pathogenesis remains elusive. In this study, we investigated for the first time the gene expression modulation of selected MED subunits in response to five viroid species (Apple fruit crinkle viroid (AFCVd), Citrus bark cracking viroid (CBCVd), Hop latent viroid (HLVd), Hop stunt viroid (HSVd), and Potato spindle tuber viroid (PSTVd)) in two model plant species (Nicotiana tabacum and N. benthamiana) and a commercially important hop (Humulus lupulus) cultivar. Our results showed a differential expression pattern of MED subunits in response to a viroid infection. The individual plant MED subunits displayed a differential and tailored expression pattern in response to different viroid species, suggesting that the MED expression is viroid- and plant species-dependent. The explicit evidence obtained from our results warrants further investigation into the association of the MED subunit with symptom development. Together, we provide a comprehensive portrait of MED subunit expression in response to viroid infection and a plausible involvement of MED subunits in fine-tuning transcriptional reprogramming in response to viroid infection, suggesting them as a potential candidate for rewiring the defense response network in plants against pathogens.
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Affiliation(s)
- Vishnu Sukumari Nath
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Ankita Shrestha
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Praveen Awasthi
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Ajay Kumar Mishra
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Tomáš Kocábek
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Jaroslav Matoušek
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Andrej Sečnik
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia; (A.S.); (J.J.)
| | - Jernej Jakše
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia; (A.S.); (J.J.)
| | - Sebastjan Radišek
- Plant Protection Department, Slovenian Institute of Hop Research and Brewing, Cesta Žalskega Tabora 2, SI-3310 Žalec, Slovenia;
| | - Vipin Hallan
- CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India;
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18
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Legrand N, Bretscher CL, Zielke S, Wilke B, Daude M, Fritz B, Diederich WE, Adhikary T. PPARβ/δ recruits NCOR and regulates transcription reinitiation of ANGPTL4. Nucleic Acids Res 2019; 47:9573-9591. [PMID: 31428774 PMCID: PMC6765110 DOI: 10.1093/nar/gkz685] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 07/20/2019] [Accepted: 07/28/2019] [Indexed: 12/24/2022] Open
Abstract
In the absence of ligands, the nuclear receptor PPARβ/δ recruits the NCOR and SMRT corepressors, which form complexes with HDAC3, to canonical target genes. Agonistic ligands cause dissociation of corepressors and enable enhanced transcription. Vice versa, synthetic inverse agonists augment corepressor recruitment and repression. Both basal repression of the target gene ANGPTL4 and reinforced repression elicited by inverse agonists are partially insensitive to HDAC inhibition. This raises the question how PPARβ/δ represses transcription mechanistically. We show that the PPARβ/δ inverse agonist PT-S264 impairs transcription initiation by decreasing recruitment of activating Mediator subunits, RNA polymerase II, and TFIIB, but not of TFIIA, to the ANGPTL4 promoter. Mass spectrometry identifies NCOR as the main PT-S264-dependent interactor of PPARβ/δ. Reconstitution of knockout cells with PPARβ/δ mutants deficient in basal repression results in diminished recruitment of NCOR, SMRT, and HDAC3 to PPAR target genes, while occupancy by RNA polymerase II is increased. PT-S264 restores binding of NCOR, SMRT, and HDAC3 to the mutants, resulting in reduced polymerase II occupancy. Our findings corroborate deacetylase-dependent and -independent repressive functions of HDAC3-containing complexes, which act in parallel to downregulate transcription.
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Affiliation(s)
- Nathalie Legrand
- Department of Medicine, Institute for Molecular Biology and Tumour Research, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
| | - Clemens L Bretscher
- Department of Medicine, Institute for Molecular Biology and Tumour Research, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
| | - Svenja Zielke
- Department of Medicine, Institute for Molecular Biology and Tumour Research, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
| | - Bernhard Wilke
- Department of Medicine, Institute for Molecular Biology and Tumour Research, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany.,Department of Medicine, Institute for Medical Bioinformatics and Biostatistics, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
| | - Michael Daude
- Core Facility Medicinal Chemistry, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
| | - Barbara Fritz
- Centre for Human Genetics, Universitätsklinikum Giessen und Marburg GmbH, Baldingerstrasse, 35043 Marburg, Germany
| | - Wibke E Diederich
- Core Facility Medicinal Chemistry, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany.,Department of Pharmacy, Institute for Pharmaceutical Chemistry, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
| | - Till Adhikary
- Department of Medicine, Institute for Molecular Biology and Tumour Research, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany.,Department of Medicine, Institute for Medical Bioinformatics and Biostatistics, Centre for Tumour Biology and Immunology, Philipps University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
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19
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Maji S, Dahiya P, Waseem M, Dwivedi N, Bhat DS, Dar TH, Thakur JK. Interaction map of Arabidopsis Mediator complex expounding its topology. Nucleic Acids Res 2019; 47:3904-3920. [PMID: 30793213 PMCID: PMC6486561 DOI: 10.1093/nar/gkz122] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/04/2019] [Accepted: 02/20/2019] [Indexed: 01/28/2023] Open
Abstract
Understanding of mechanistic details of Mediator functioning in plants is impeded as the knowledge of subunit organization and structure is lacking. In this study, an interaction map of Arabidopsis Mediator complex was analyzed to understand the arrangement of the subunits in the core part of the complex. Combining this interaction map with homology-based modeling, probable structural topology of core part of the Arabidopsis Mediator complex was deduced. Though the overall topology of the complex was similar to that of yeast, several differences were observed. Many interactions discovered in this study are not yet reported in other systems. AtMed14 and AtMed17 emerged as the key component providing important scaffold for the whole complex. AtMed6 and AtMed10 were found to be important for linking head with middle and middle with tail, respectively. Some Mediator subunits were found to form homodimers and some were found to possess transactivation property. Subcellular localization suggested that many of the Mediator subunits might have functions beyond the process of transcription. Overall, this study reveals role of individual subunits in the organization of the core complex, which can be an important resource for understanding the molecular mechanism of functioning of Mediator complex and its subunits in plants.
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Affiliation(s)
- Sourobh Maji
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Pradeep Dahiya
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Mohd Waseem
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Nidhi Dwivedi
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Divya S Bhat
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Tanvir H Dar
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Jitendra K Thakur
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
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20
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Gottesfeld JM. Milestones in transcription and chromatin published in the Journal of Biological Chemistry. J Biol Chem 2019; 294:1652-1660. [PMID: 30710013 DOI: 10.1074/jbc.tm118.004162] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
During Herbert Tabor's tenure as Editor-in-Chief from 1971 to 2010, JBC has published many seminal papers in the fields of chromatin structure, epigenetics, and regulation of transcription in eukaryotes. As of this writing, more than 21,000 studies on gene transcription at the molecular level have been published in JBC since 1971. This brief review will attempt to highlight some of these ground-breaking discoveries and show how early studies published in JBC have influenced current research. Papers published in the Journal have reported the initial discovery of multiple forms of RNA polymerase in eukaryotes, identification and purification of essential components of the transcription machinery, and identification and mechanistic characterization of various transcriptional activators and repressors and include studies on chromatin structure and post-translational modifications of the histone proteins. The large body of literature published in the Journal has inspired current research on how chromatin organization and epigenetics impact regulation of gene expression.
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Affiliation(s)
- Joel M Gottesfeld
- Departments of Molecular Medicine and Chemistry, The Scripps Research Institute, La Jolla, California 92037.
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21
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Smad7:β-catenin complex regulates myogenic gene transcription. Cell Death Dis 2019; 10:387. [PMID: 31097718 PMCID: PMC6522533 DOI: 10.1038/s41419-019-1615-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/30/2019] [Accepted: 04/23/2019] [Indexed: 12/17/2022]
Abstract
Recent reports indicate that Smad7 promotes skeletal muscle differentiation and growth. We previously documented a non-canonical role of nuclear Smad7 during myogenesis, independent of its role in TGF-β signaling. Here further characterization of the myogenic function of Smad7 revealed β-catenin as a Smad7 interacting protein. Biochemical analysis identified a Smad7 interaction domain (SID) between aa575 and aa683 of β-catenin. Reporter gene analysis and chromatin immunoprecipitation demonstrated that Smad7 and β-catenin are cooperatively recruited to the extensively characterized ckm promoter proximal region to facilitate its muscle restricted transcriptional activation in myogenic cells. Depletion of endogenous Smad7 and β-catenin in muscle cells reduced ckm promoter activity indicating their role during myogenesis. Deletion of the β-catenin SID substantially reduced the effect of Smad7 on the ckm promoter and exogenous expression of SID abolished β-catenin function, indicating that SID functions as a trans dominant-negative regulator of β-catenin activity. β-catenin interaction with the Mediator kinase complex through its Med12 subunit led us to identify MED13 as an additional Smad7-binding partner. Collectively, these studies document a novel function of a Smad7-MED12/13-β-catenin complex at the ckm locus, indicating a key role of this complex in the program of myogenic gene expression underlying skeletal muscle development and regeneration.
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22
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O’Hare EA, Antin PB, Delany ME. Two Proximally Close Priority Candidate Genes for diplopodia-1, an Autosomal Inherited Craniofacial-Limb Syndrome in the Chicken: MRE11 and GPR83. J Hered 2019; 110:194-210. [PMID: 30597046 PMCID: PMC6399517 DOI: 10.1093/jhered/esy071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 12/29/2018] [Indexed: 11/12/2022] Open
Abstract
Next-generation sequencing (NGS) and expression technologies were utilized to investigate the genes and sequence elements in a 586 kb region of chicken chromosome 1 associated with the autosomal recessive diplopodia-1 (dp-1) mutation. This mutation shows a syndromic phenotype similar to known human developmental abnormalities (e.g., cleft palate, polydactyly, omphalocele [exposed viscera]). Toward our goal to ascertain the variant responsible, the entire 586 kb region was sequenced following utilization of a specifically designed capture array and to confirm/validate fine-mapping results. Bioinformatic analyses identified a total of 6142 sequence variants, which included SNPs, indels, and gaps. Of these, 778 SNPs, 146 micro-indels, and 581 gaps were unique to the UCD-Dp-1.003 inbred congenic line; those found within exons and splice sites were studied for contribution to the mutant phenotype. Upon further validation with additional mutant samples, a smaller subset (of variants [51]) remains linked to the mutation. Additionally, utilization of specific samples in the NGS technology was advantageous in that fine-mapping methodologies eliminated an additional 326 kb of sequence information on chromosome 1. Predicted and confirmed protein-coding genes within the smaller 260 kb region were assessed for their developmental expression patterns over several stages of early embryogenesis in regions/tissues of interest (e.g., digits, craniofacial region). Based on these results and known function in other vertebrates, 2 genes within 5 kb of each other, MRE11 and GPR83, are proposed as high-priority candidates for the dp-1 mutation.
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Affiliation(s)
- Elizabeth A O’Hare
- Department of Animal Science, University of California, Davis, CA
- Elizabeth A. O’Hare is now at the Department of Biological Sciences, Towson University, Towson, MD
| | - Parker B Antin
- Department of Molecular and Cellular Medicine, University of Arizona, Tucson, AZ
| | - Mary E Delany
- Department of Animal Science, University of California, Davis, CA
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Mediator, known as a coactivator, can act in transcription initiation in an activator-independent manner in vivo. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:687-696. [DOI: 10.1016/j.bbagrm.2018.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/28/2018] [Accepted: 07/04/2018] [Indexed: 01/20/2023]
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24
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Abstract
Alterations in the regulation of gene expression are frequently associated with developmental diseases or cancer. Transcription activation is a key phenomenon in the regulation of gene expression. In all eukaryotes, mediator of RNA polymerase II transcription (Mediator), a large complex with modular organization, is generally required for transcription by RNA polymerase II, and it regulates various steps of this process. The main function of Mediator is to transduce signals from the transcription activators bound to enhancer regions to the transcription machinery, which is assembled at promoters as the preinitiation complex (PIC) to control transcription initiation. Recent functional studies of Mediator with the use of structural biology approaches and functional genomics have revealed new insights into Mediator activity and its regulation during transcription initiation, including how Mediator is recruited to transcription regulatory regions and how it interacts and cooperates with PIC components to assist in PIC assembly. Novel roles of Mediator in the control of gene expression have also been revealed by showing its connection to the nuclear pore and linking Mediator to the regulation of gene positioning in the nuclear space. Clear links between Mediator subunits and disease have also encouraged studies to explore targeting of this complex as a potential therapeutic approach in cancer and fungal infections.
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Affiliation(s)
- Julie Soutourina
- Institute for Integrative Biology of the Cell (I2BC), Institute of Life Sciences Frédéric Joliot, Commissariat à l'énergie Atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), University Paris Sud, University Paris Saclay, F-91198 Gif-sur-Yvette, France
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25
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Eychenne T, Werner M, Soutourina J. Toward understanding of the mechanisms of Mediator function in vivo: Focus on the preinitiation complex assembly. Transcription 2017; 8:328-342. [PMID: 28841352 DOI: 10.1080/21541264.2017.1329000] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mediator is a multisubunit complex conserved in eukaryotes that plays an essential coregulator role in RNA polymerase (Pol) II transcription. Despite intensive studies of the Mediator complex, the molecular mechanisms of its function in vivo remain to be fully defined. In this review, we will discuss the different aspects of Mediator function starting with its interactions with specific transcription factors, its recruitment to chromatin and how, as a coregulator, it contributes to the assembly of transcription machinery components within the preinitiation complex (PIC) in vivo and beyond the PIC formation.
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Affiliation(s)
- Thomas Eychenne
- a Institute for Integrative Biology of the Cell (I2BC), Institute of Life Sciences Frédéric Joliot, CEA, CNRS , Univ. Paris Sud, University Paris Saclay , Gif-sur-Yvette , France.,b Institut Pasteur, (Epi)genomics of Animal Development Unit , Development and Stem Cell Biology Department, CNRS UMR3778 , Paris , France
| | - Michel Werner
- a Institute for Integrative Biology of the Cell (I2BC), Institute of Life Sciences Frédéric Joliot, CEA, CNRS , Univ. Paris Sud, University Paris Saclay , Gif-sur-Yvette , France
| | - Julie Soutourina
- a Institute for Integrative Biology of the Cell (I2BC), Institute of Life Sciences Frédéric Joliot, CEA, CNRS , Univ. Paris Sud, University Paris Saclay , Gif-sur-Yvette , France
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26
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Krivega I, Dean A. LDB1-mediated enhancer looping can be established independent of mediator and cohesin. Nucleic Acids Res 2017; 45:8255-8268. [PMID: 28520978 PMCID: PMC5737898 DOI: 10.1093/nar/gkx433] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 05/02/2017] [Accepted: 05/05/2017] [Indexed: 12/25/2022] Open
Abstract
Mechanistic studies in erythroid cells indicate that LDB1, as part of a GATA1/TAL1/LMO2 complex, brings erythroid-expressed genes into proximity with enhancers for transcription activation. The role of co-activators in establishing this long-range interaction is poorly understood. Here we tested the contributions of the RNA Pol II pre-initiation complex (PIC), mediator and cohesin to establishment of locus control region (LCR)/β-globin proximity. CRISPR/Cas9 editing of the β-globin promoter to eliminate the RNA Pol II PIC by deleting the TATA-box resulted in loss of transcription, but enhancer-promoter interaction was unaffected. Additional deletion of the promoter GATA1 site eliminated LDB1 complex and mediator occupancy and resulted in loss of LCR/β-globin proximity. To separate the roles of LDB1 and mediator in LCR looping, we expressed a looping-competent but transcription-activation deficient form of LDB1 in LDB1 knock down cells: LCR/β-globin proximity was restored without mediator core occupancy. Further, Cas9-directed tethering of mutant LDB1 to the β-globin promoter forced LCR loop formation in the absence of mediator or cohesin occupancy. Moreover, ENCODE data and our chromatin immunoprecipitation results indicate that cohesin is almost completely absent from validated and predicted LDB1-regulated erythroid enhancer-gene pairs. Thus, lineage specific factors largely mediate enhancer-promoter looping in erythroid cells independent of mediator and cohesin.
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MESH Headings
- Animals
- Base Sequence
- Blotting, Western
- CRISPR-Cas Systems
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cell Line, Tumor
- Chromosomal Proteins, Non-Histone/genetics
- Chromosomal Proteins, Non-Histone/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Enhancer Elements, Genetic/genetics
- Gene Expression Regulation, Leukemic
- LIM Domain Proteins/genetics
- LIM Domain Proteins/metabolism
- Leukemia, Erythroblastic, Acute/genetics
- Leukemia, Erythroblastic, Acute/metabolism
- Leukemia, Erythroblastic, Acute/pathology
- Locus Control Region/genetics
- Mice
- Promoter Regions, Genetic/genetics
- RNA Polymerase II/genetics
- RNA Polymerase II/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- beta-Globins/genetics
- Cohesins
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Affiliation(s)
- Ivan Krivega
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ann Dean
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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27
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Malik N, Agarwal P, Tyagi A. Emerging functions of multi-protein complex Mediator with special emphasis on plants. Crit Rev Biochem Mol Biol 2017; 52:475-502. [DOI: 10.1080/10409238.2017.1325830] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Naveen Malik
- National Institute of Plant Genome Research (NIPGR), New Delhi, India
| | - Pinky Agarwal
- National Institute of Plant Genome Research (NIPGR), New Delhi, India
| | - Akhilesh Tyagi
- National Institute of Plant Genome Research (NIPGR), New Delhi, India
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
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28
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Montes M, Moreira-Ramos S, Rojas DA, Urbina F, Käufer NF, Maldonado E. RNA polymerase II components and Rrn7 form a preinitiation complex on the HomolD box to promote ribosomal protein gene expression in Schizosaccharomyces pombe. FEBS J 2017; 284:615-633. [PMID: 28060464 DOI: 10.1111/febs.14006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 12/02/2016] [Accepted: 01/05/2017] [Indexed: 01/29/2023]
Abstract
In Schizosaccharomyces pombe, ribosomal protein gene (RPG) promoters contain a TATA box analog, the HomolD box, which is bound by the Rrn7 protein. Despite the importance of ribosome biogenesis for cell survival, the mechanisms underlying RPG transcription remain unknown. In this study, we found that components of the RNA polymerase II (RNAPII) system, consisting of the initiation or general transcription factors (GTFs) TFIIA, IIB, IIE, TATA-binding protein (TBP) and the RNAPII holoenzyme, interacted directly with Rrn7 in vitro, and were able to form a preinitiation complex (PIC) on the HomolD box. PIC complex formation follows an ordered pathway on these promoters. The GTFs and RNAPII can also be cross-linked to HomolD-containing promoters in vivo. In an in vitro reconstituted transcription system, RNAPII components and Rrn7 were necessary for HomolD-directed transcription. The Mediator complex was required for basal transcription from those promoters in whole cell extract (WCE). The Med17 subunit of Mediator also can be cross-linked to the promoter region of HomolD-containing promoters in vivo, suggesting the presence of the Mediator complex on HomolD box-containing promoters. Together, these data show that components of the RNAPII machinery and Rrn7 participate in the PIC assembly on the HomolD box, thereby directing RPG transcription.
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Affiliation(s)
- Matías Montes
- Programa Biología Celular y Molecular, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Sandra Moreira-Ramos
- Programa Biología Celular y Molecular, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Diego A Rojas
- Microbiología y Micología, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Fabiola Urbina
- Programa Biología Celular y Molecular, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Norbert F Käufer
- Institute of Genetics, Technische Universität Braunschweig, Germany
| | - Edio Maldonado
- Programa Biología Celular y Molecular, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
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29
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Alam MA, Kelly JM. Proteins interacting with CreA and CreB in the carbon catabolite repression network in Aspergillus nidulans. Curr Genet 2016; 63:669-683. [PMID: 27915380 DOI: 10.1007/s00294-016-0667-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 11/26/2022]
Abstract
In Aspergillus nidulans, carbon catabolite repression (CCR) is mediated by the global repressor protein CreA. The deubiquitinating enzyme CreB is a component of the CCR network. Genetic interaction was confirmed using a strain containing complete loss-of-function alleles of both creA and creB. No direct physical interaction was identified between tagged versions of CreA and CreB. To identify any possible protein(s) that may form a bridge between CreA and CreB, we purified both proteins from mycelia grown in media that result in repression or derepression. The purified proteins were analysed by LC/MS and identified using MaxQuant and Mascot databases. For both CreA and CreB, 47 proteins were identified in repressing and derepressing conditions. Orthologues of the co-purified proteins were identified in S. cerevisiae and humans. Gene ontology analyses of A. nidulans proteins and yeast and human orthologues were performed. Functional annotation analysis revealed that proteins that preferentially interact with CreA in repressing conditions include histones and histone transcription regulator 3 (Hir3). Proteins interacting with CreB tend to be involved in cellular transportation and organization. Similar findings were obtained using yeast and human orthologues, although the yeast background generated a number of other biological processes involving Mig1p which were not present in the A. nidulans or human background analyses. Hir3 was present in repressing conditions for CreA and in both growth conditions for CreB, suggesting that Hir3, or proteins interacting with Hir3, could be a possible target of CreB.
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Affiliation(s)
- Md Ashiqul Alam
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, SA, Australia
| | - Joan M Kelly
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, SA, Australia.
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30
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Malik S, Molina H, Xue Z. PIC Activation through Functional Interplay between Mediator and TFIIH. J Mol Biol 2016; 429:48-63. [PMID: 27916598 DOI: 10.1016/j.jmb.2016.11.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 11/26/2016] [Accepted: 11/27/2016] [Indexed: 10/20/2022]
Abstract
The multiprotein Mediator coactivator complex functions in large part by controlling the formation and function of the promoter-bound preinitiation complex (PIC), which consists of RNA polymerase II and general transcription factors. However, precisely how Mediator impacts the PIC, especially post-recruitment, has remained unclear. Here, we have studied Mediator effects on basal transcription in an in vitro transcription system reconstituted from purified components. Our results reveal a close functional interplay between Mediator and TFIIH in the early stages of PIC development. We find that under conditions when TFIIH is not normally required for transcription, Mediator actually represses transcription. TFIIH, whose recruitment to the PIC is known to be facilitated by the Mediator, then acts to relieve Mediator-induced repression to generate an active form of the PIC. Gel mobility shift analyses of PICs and characterization of TFIIH preparations carrying mutant XPB translocase subunit further indicate that this relief of repression is achieved through expending energy via ATP hydrolysis, suggesting that it is coupled to TFIIH's established promoter melting activity. Our interpretation of these results is that Mediator functions as an assembly factor that facilitates PIC maturation through its various stages. Whereas the overall effect of the Mediator is to stimulate basal transcription, its initial engagement with the PIC generates a transcriptionally inert PIC intermediate, which necessitates energy expenditure to complete the process.
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Affiliation(s)
- Sohail Malik
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
| | - Henrik Molina
- Proteomics Resource Center, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Zhu Xue
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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31
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Eychenne T, Novikova E, Barrault MB, Alibert O, Boschiero C, Peixeiro N, Cornu D, Redeker V, Kuras L, Nicolas P, Werner M, Soutourina J. Functional interplay between Mediator and TFIIB in preinitiation complex assembly in relation to promoter architecture. Genes Dev 2016; 30:2119-2132. [PMID: 27688401 PMCID: PMC5066617 DOI: 10.1101/gad.285775.116] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 09/12/2016] [Indexed: 11/24/2022]
Abstract
Mediator is a large coregulator complex conserved from yeast to humans and involved in many human diseases, including cancers. Together with general transcription factors, it stimulates preinitiation complex (PIC) formation and activates RNA polymerase II (Pol II) transcription. In this study, we analyzed how Mediator acts in PIC assembly using in vivo, in vitro, and in silico approaches. We revealed an essential function of the Mediator middle module exerted through its Med10 subunit, implicating a key interaction between Mediator and TFIIB. We showed that this Mediator-TFIIB link has a global role on PIC assembly genome-wide. Moreover, the amplitude of Mediator's effect on PIC formation is gene-dependent and is related to the promoter architecture in terms of TATA elements, nucleosome occupancy, and dynamics. This study thus provides mechanistic insights into the coordinated function of Mediator and TFIIB in PIC assembly in different chromatin contexts.
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Affiliation(s)
- Thomas Eychenne
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Énergie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris Sud, Université Paris Saclay, F-91198 Gif-sur-Yvette Cedex, France.,Institut de Biologie et de Technologies de Saclay (IBITECS), CEA, F-91191 Gif-sur-Yvette Cedex, France
| | - Elizaveta Novikova
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Énergie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris Sud, Université Paris Saclay, F-91198 Gif-sur-Yvette Cedex, France.,Institut de Biologie et de Technologies de Saclay (IBITECS), CEA, F-91191 Gif-sur-Yvette Cedex, France
| | - Marie-Bénédicte Barrault
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Énergie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris Sud, Université Paris Saclay, F-91198 Gif-sur-Yvette Cedex, France.,Institut de Biologie et de Technologies de Saclay (IBITECS), CEA, F-91191 Gif-sur-Yvette Cedex, France
| | - Olivier Alibert
- Laboratoire d'Exploration Fonctionnelle des Génomes (LEFG), Institut de Radiobiologie Cellulaire et Moléculaire (IRCM), CEA, Genopole G2, F-91057 Evry Cedex, France
| | - Claire Boschiero
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Énergie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris Sud, Université Paris Saclay, F-91198 Gif-sur-Yvette Cedex, France.,Institut de Biologie et de Technologies de Saclay (IBITECS), CEA, F-91191 Gif-sur-Yvette Cedex, France
| | - Nuno Peixeiro
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Énergie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris Sud, Université Paris Saclay, F-91198 Gif-sur-Yvette Cedex, France.,Institut de Biologie et de Technologies de Saclay (IBITECS), CEA, F-91191 Gif-sur-Yvette Cedex, France
| | - David Cornu
- Service d'Identification et de Caractérisation des Protéines par Spectrométrie de Masse (SICaPS), CNRS, F-91198 Gif-sur-Yvette Cedex, France
| | - Virginie Redeker
- Service d'Identification et de Caractérisation des Protéines par Spectrométrie de Masse (SICaPS), CNRS, F-91198 Gif-sur-Yvette Cedex, France.,Paris-Saclay Institute of Neuroscience (Neuro-PSI), CNRS, F-91198 Gif-sur-Yvette Cedex, France
| | - Laurent Kuras
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Énergie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris Sud, Université Paris Saclay, F-91198 Gif-sur-Yvette Cedex, France
| | - Pierre Nicolas
- Mathematiques et Informatique Appliquées du Génome à l'Environnement (MaIAGE), Institut National de la Recherche Agronomique (INRA), Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Michel Werner
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Énergie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris Sud, Université Paris Saclay, F-91198 Gif-sur-Yvette Cedex, France.,Institut de Biologie et de Technologies de Saclay (IBITECS), CEA, F-91191 Gif-sur-Yvette Cedex, France
| | - Julie Soutourina
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Énergie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris Sud, Université Paris Saclay, F-91198 Gif-sur-Yvette Cedex, France.,Institut de Biologie et de Technologies de Saclay (IBITECS), CEA, F-91191 Gif-sur-Yvette Cedex, France
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32
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Abstract
The preimplantation development stage of mammalian embryogenesis consists of a series of highly conserved, regulated, and predictable cell divisions. This process is essential to allow the rapid expansion and differentiation of a single-cell zygote into a multicellular blastocyst containing cells of multiple developmental lineages. This period of development, also known as the germinal stage, encompasses several important developmental transitions, which are accompanied by dramatic changes in cell cycle profiles and dynamics. These changes are driven primarily by differences in the establishment and enforcement of cell cycle checkpoints, which must be bypassed to facilitate the completion of essential cell cycle events. Much of the current knowledge in this area has been amassed through the study of knockout models in mice. These mouse models are powerful experimental tools, which have allowed us to dissect the relative dependence of the early embryonic cell cycles on various aspects of the cell cycle machinery and highlight the extent of functional redundancy between members of the same gene family. This chapter will explore the ways in which the cell cycle machinery, their accessory proteins, and their stimuli operate during mammalian preimplantation using mouse models as a reference and how this allows for the usually well-defined stages of the cell cycle to be shaped and transformed during this unique and critical stage of development.
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33
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Plaschka C, Nozawa K, Cramer P. Mediator Architecture and RNA Polymerase II Interaction. J Mol Biol 2016; 428:2569-2574. [PMID: 26851380 DOI: 10.1016/j.jmb.2016.01.028] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 01/26/2016] [Accepted: 01/27/2016] [Indexed: 12/18/2022]
Abstract
Integrated structural biology recently elucidated the architecture of Mediator and its position on RNA polymerase II. Here we summarize these achievements and list open questions on Mediator structure and mechanism.
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Affiliation(s)
- Clemens Plaschka
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Kayo Nozawa
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Patrick Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany.
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34
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Allen BL, Taatjes DJ. The Mediator complex: a central integrator of transcription. Nat Rev Mol Cell Biol 2015; 16:155-66. [PMID: 25693131 DOI: 10.1038/nrm3951] [Citation(s) in RCA: 604] [Impact Index Per Article: 67.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The RNA polymerase II (Pol II) enzyme transcribes all protein-coding and most non-coding RNA genes and is globally regulated by Mediator - a large, conformationally flexible protein complex with a variable subunit composition (for example, a four-subunit cyclin-dependent kinase 8 module can reversibly associate with it). These biochemical characteristics are fundamentally important for Mediator's ability to control various processes that are important for transcription, including the organization of chromatin architecture and the regulation of Pol II pre-initiation, initiation, re-initiation, pausing and elongation. Although Mediator exists in all eukaryotes, a variety of Mediator functions seem to be specific to metazoans, which is indicative of more diverse regulatory requirements.
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Affiliation(s)
- Benjamin L Allen
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
| | - Dylan J Taatjes
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
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35
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Plaschka C, Larivière L, Wenzeck L, Seizl M, Hemann M, Tegunov D, Petrotchenko EV, Borchers CH, Baumeister W, Herzog F, Villa E, Cramer P. Architecture of the RNA polymerase II-Mediator core initiation complex. Nature 2015; 518:376-80. [PMID: 25652824 DOI: 10.1038/nature14229] [Citation(s) in RCA: 227] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 01/14/2015] [Indexed: 12/12/2022]
Abstract
The conserved co-activator complex Mediator enables regulated transcription initiation by RNA polymerase (Pol) II. Here we reconstitute an active 15-subunit core Mediator (cMed) comprising all essential Mediator subunits from Saccharomyces cerevisiae. The cryo-electron microscopic structure of cMed bound to a core initiation complex was determined at 9.7 Å resolution. cMed binds Pol II around the Rpb4-Rpb7 stalk near the carboxy-terminal domain (CTD). The Mediator head module binds the Pol II dock and the TFIIB ribbon and stabilizes the initiation complex. The Mediator middle module extends to the Pol II foot with a 'plank' that may influence polymerase conformation. The Mediator subunit Med14 forms a 'beam' between the head and middle modules and connects to the tail module that is predicted to bind transcription activators located on upstream DNA. The Mediator 'arm' and 'hook' domains contribute to a 'cradle' that may position the CTD and TFIIH kinase to stimulate Pol II phosphorylation.
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Affiliation(s)
- C Plaschka
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - L Larivière
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - L Wenzeck
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - M Seizl
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - M Hemann
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - D Tegunov
- Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - E V Petrotchenko
- Department of Biochemistry and Microbiology, Genome British Columbia Protein Centre, University of Victoria, 3101-4464 Markham Street, Victoria, British Columbia V8Z7X8, Canada
| | - C H Borchers
- Department of Biochemistry and Microbiology, Genome British Columbia Protein Centre, University of Victoria, 3101-4464 Markham Street, Victoria, British Columbia V8Z7X8, Canada
| | - W Baumeister
- Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - F Herzog
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - E Villa
- 1] Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany [2] Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - P Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
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Samanta S, Thakur JK. Importance of Mediator complex in the regulation and integration of diverse signaling pathways in plants. FRONTIERS IN PLANT SCIENCE 2015; 6:757. [PMID: 26442070 PMCID: PMC4584954 DOI: 10.3389/fpls.2015.00757] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/04/2015] [Indexed: 05/19/2023]
Abstract
Basic transcriptional machinery in eukaryotes is assisted by a number of cofactors, which either increase or decrease the rate of transcription. Mediator complex is one such cofactor, and recently has drawn a lot of interest because of its integrative power to converge different signaling pathways before channeling the transcription instructions to the RNA polymerase II machinery. Like yeast and metazoans, plants do possess the Mediator complex across the kingdom, and its isolation and subunit analyses have been reported from the model plant, Arabidopsis. Genetic, and molecular analyses have unraveled important regulatory roles of Mediator subunits at every stage of plant life cycle starting from flowering to embryo and organ development, to even size determination. It also contributes immensely to the survival of plants against different environmental vagaries by the timely activation of its resistance mechanisms. Here, we have provided an overview of plant Mediator complex starting from its discovery to regulation of stoichiometry of its subunits. We have also reviewed involvement of different Mediator subunits in different processes and pathways including defense response pathways evoked by diverse biotic cues. Wherever possible, attempts have been made to provide mechanistic insight of Mediator's involvement in these processes.
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Affiliation(s)
| | - Jitendra K. Thakur
- *Correspondence: Jitendra K. Thakur, Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
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Reconstitution of active human core Mediator complex reveals a critical role of the MED14 subunit. Nat Struct Mol Biol 2014; 21:1028-34. [PMID: 25383669 PMCID: PMC4259101 DOI: 10.1038/nsmb.2914] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/09/2014] [Indexed: 01/01/2023]
Abstract
The evolutionarily conserved Mediator complex is a critical coactivator for RNA polymerase II (Pol II)-mediated transcription. Here, we report the reconstitution of a functional 15-subunit human core Mediator complex and its characterization by functional assays and chemical cross-linking coupled to mass spectrometry (CX-MS). Whereas the reconstituted head and middle modules can stably associate, only with incorporation of MED14 into the bi-modular complex does it acquire basal and coactivator functions. This results from a dramatically enhanced ability of MED14-containing complexes to associate with Pol II. Altogether, our analyses identify MED14 as both an architectural and a functional backbone of the Mediator complex. We further establish a conditional requirement for metazoan-specific MED26 that becomes evident in the presence of heterologous nuclear factors. This general approach paves the way for systematically dissecting the multiple layers of functionalities associated with the Mediator complex.
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Di Tommaso S, Tinelli A, Malvasi A, Massari S. Missense mutations in exon 2 of the MED12 gene are involved in IGF-2 overexpression in uterine leiomyoma. Mol Hum Reprod 2014; 20:1009-15. [PMID: 25015674 DOI: 10.1093/molehr/gau055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Uterine leiomyoma (UL), the most common benign tumour found in females, is associated with many recurrent genetic aberrations, such as translocations, interstitial deletions and specific germline mutations. Among these, mutations affecting exon 2 of the mediator complex subunit 12 (MED12) gene are commonly detected in the majority of ULs. Mutational analysis of the MED12 gene, performed on 36 UL samples, revealed that 12 leiomyomas (33.4%) exhibited heterozygous missense mutations in codon 44 of exon 2 of the MED12 gene, four leiomyomas (11.1%) showed internal in-frame deletions, and two leiomyomas (5.5%) exhibited deletions involving intron 1-exon 2 junction, which caused a predicted loss of the splice acceptor. No mutations were detected in uterine myometrium (UM) and pseudocapsule (PC) samples, including those from women with a MED12 mutation in UL. These data showed that the PC is a healthy tissue that surrounds the UL to maintain UM integrity. Analysis of insulin-like growth factor 2 (IGF-2) and collagen type IV alpha 2 (COL4A2) mRNA expression levels in the same set of ULs revealed that only those with MED12 missense mutations expressed significantly higher levels of IGF-2 mRNA. In contrast, MED12 gene status does not appear to affect mRNA expression levels of the COL4A2 gene. On the basis of this finding, we suggest that the MED12 status stratifies the ULs into two mutually exclusive pathways of leiomyoma genesis, one with IGF-2 overexpression and the other with no IGF-2 activation. The occurrence of IGF-2 overexpression could be therapeutically targeted for the non-surgical treatment of leiomyomas.
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Affiliation(s)
- S Di Tommaso
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce 73100, Italy
| | - A Tinelli
- Division of Experimental Endoscopic Surgery, Imaging, Minimally Invasive Therapy and Technology, Department of Gynecology and Obstetrics, Vito Fazzi Hospital, Lecce 73100, Italy
| | - A Malvasi
- Department of Obstetrics and Gynecology, Santa Maria Hospital, Bari 70100, Italy
| | - S Massari
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce 73100, Italy
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Wang X, Sun Q, Ding Z, Ji J, Wang J, Kong X, Yang J, Cai G. Redefining the modular organization of the core Mediator complex. Cell Res 2014; 24:796-808. [PMID: 24810298 PMCID: PMC4085763 DOI: 10.1038/cr.2014.64] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 02/13/2014] [Accepted: 03/13/2014] [Indexed: 01/24/2023] Open
Abstract
The Mediator complex plays an essential role in the regulation of eukaryotic transcription. The Saccharomyces cerevisiae core Mediator comprises 21 subunits, which are organized into Head, Middle and Tail modules. Previously, the Head module was assigned to a distinct dense domain at the base, and the Middle and Tail modules were identified to form a tight structure above the Head module, which apparently contradicted findings from many biochemical and functional studies. Here, we compared the structures of the core Mediator and its subcomplexes, especially the first 3D structure of the Head + Middle modules, which permitted an unambiguous assignment of the three modules. Furthermore, nanogold labeling pinpointing four Mediator subunits from different modules conclusively validated the modular assignment, in which the Head and Middle modules fold back on one another and form the upper portion of the core Mediator, while the Tail module forms a distinct dense domain at the base. The new modular model of the core Mediator has reconciled the previous inconsistencies between the structurally and functionally defined Mediator modules. Collectively, these analyses completely redefine the modular organization of the core Mediator, which allow us to integrate the structural and functional information into a coherent mechanism for the Mediator's modularity and regulation in transcription initiation.
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Affiliation(s)
- Xuejuan Wang
- School of Life Sciences, University of Science and Technology of China, 443 Huang-Shan Road, Hefei, Anhui 230027, China
| | - Qianqian Sun
- School of Life Sciences, University of Science and Technology of China, 443 Huang-Shan Road, Hefei, Anhui 230027, China
| | - Zhenrui Ding
- School of Life Sciences, University of Science and Technology of China, 443 Huang-Shan Road, Hefei, Anhui 230027, China
| | - Jinhua Ji
- School of Life Sciences, University of Science and Technology of China, 443 Huang-Shan Road, Hefei, Anhui 230027, China
| | - Jianye Wang
- School of Life Sciences, University of Science and Technology of China, 443 Huang-Shan Road, Hefei, Anhui 230027, China
| | - Xiao Kong
- School of Life Sciences, University of Science and Technology of China, 443 Huang-Shan Road, Hefei, Anhui 230027, China
| | - Jianghong Yang
- School of Life Sciences, University of Science and Technology of China, 443 Huang-Shan Road, Hefei, Anhui 230027, China
| | - Gang Cai
- 1] School of Life Sciences, University of Science and Technology of China, 443 Huang-Shan Road, Hefei, Anhui 230027, China [2] Hefei National Laboratory for Physical Sciences at the Microscale, Center for Integrative Imaging, 443 Huang-Shan Road, Hefei, Anhui 230027, China [3] Center for Biomedical Engineering, University of Science and Technology of China, 443 Huang-Shan Road, Hefei, Anhui 230027, China
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40
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Jeronimo C, Robert F. Kin28 regulates the transient association of Mediator with core promoters. Nat Struct Mol Biol 2014; 21:449-55. [PMID: 24704787 PMCID: PMC3997488 DOI: 10.1038/nsmb.2810] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/11/2014] [Indexed: 12/23/2022]
Abstract
Mediator is an essential, broadly used eukaryotic transcriptional coactivator. How and what Mediator communicates from activators to RNA polymerase II (RNAPII) remains an open question. Here we performed genome-wide location profiling of Saccharomyces cerevisiae Mediator subunits. Mediator is not found at core promoters but rather occupies the upstream activating sequence, upstream of the pre-initiation complex. In the absence of Kin28 (CDK7) kinase activity or in cells in which the RNAPII C-terminal domain is mutated to replace Ser5 with alanine, however, Mediator accumulates at core promoters together with RNAPII. We propose that Mediator is released quickly from promoters after phosphorylation of Ser5 by Kin28 (CDK7), which also allows for RNAPII to escape from the promoter.
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Affiliation(s)
- Célia Jeronimo
- Institut de recherches cliniques de Montréal, Montréal, Québec, Canada
| | - François Robert
- 1] Institut de recherches cliniques de Montréal, Montréal, Québec, Canada. [2] Département de Médecine, Université de Montréal, Montréal, Québec, Canada
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Serrat N, Sebastian C, Pereira-Lopes S, Valverde-Estrella L, Lloberas J, Celada A. The Response of Secondary Genes to Lipopolysaccharides in Macrophages Depends on Histone Deacetylase and Phosphorylation of C/EBPβ. THE JOURNAL OF IMMUNOLOGY 2013; 192:418-26. [DOI: 10.4049/jimmunol.1203500] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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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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43
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Lacombe T, Poh SL, Barbey R, Kuras L. Mediator is an intrinsic component of the basal RNA polymerase II machinery in vivo. Nucleic Acids Res 2013; 41:9651-62. [PMID: 23963697 PMCID: PMC3834807 DOI: 10.1093/nar/gkt701] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Mediator is a prominent multisubunit coactivator that functions as a bridge between gene-specific activators and the basal RNA polymerase (Pol) II initiation machinery. Here, we study the poorly documented role of Mediator in basal, or activator-independent, transcription in vivo. We show that Mediator is still present at the promoter when the Pol II machinery is recruited in the absence of an activator, in this case through a direct fusion between a basal transcription factor and a heterologous DNA binding protein bound to the promoter. Moreover, transcription resulting from activator-independent recruitment of the Pol II machinery is impaired by inactivation of the essential Mediator subunit Med17 due to the loss of Pol II from the promoter. Our results strongly support that Mediator is an integral component of the minimal machinery essential in vivo for stable Pol II association with the promoter.
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Affiliation(s)
- Thierry Lacombe
- Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, affiliated with Université Paris-Sud, Gif-sur-Yvette 91198, France
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Heterogeneous nuclear ribonucleoprotein R cooperates with mediator to facilitate transcription reinitiation on the c-Fos gene. PLoS One 2013; 8:e72496. [PMID: 23967313 PMCID: PMC3742609 DOI: 10.1371/journal.pone.0072496] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 07/15/2013] [Indexed: 11/28/2022] Open
Abstract
The c-fos gene responds to extracellular stimuli and undergoes robust but transient transcriptional activation. Here we show that heterogeneous nuclear ribonucleoprotein R (hnRNP R) facilitates transcription reinitiation of the c-fos promoter in vitro in cooperation with Mediator. Consistently, hnRNP R interacts with the Scaffold components (Mediator, TBP, and TFIIH) as well as TFIIB, which recruits RNA polymerase II (Pol II) and TFIIF to Scaffold. The cooperative action of hnRNP R and Mediator is diminished by the cyclin-dependent kinase 8 (CDK8) module, which is comprised of CDK8, Cyclin C, MED12 and MED13 of the Mediator subunits. Interestingly, we find that the length of the G-free cassettes, and thereby their transcripts, influences the hnRNP R-mediated facilitation of reinitiation. Indeed, indicative of a possible role of the transcript in facilitating transcription reinitiation, the RNA transcript produced from the G-free cassette interacts with hnRNP R through its RNA recognition motifs (RRMs) and arginine-glycine-glycine (RGG) domain. Mutational analyses of hnRNP R indicate that facilitation of initiation and reinitiation requires distinct domains of hnRNP R. Knockdown of hnRNP R in mouse cells compromised rapid induction of the c-fos gene but did not affect transcription of constitutive genes. Together, these results suggest an important role for hnRNP R in regulating robust response of the c-fos gene.
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45
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Ansari SA, Morse RH. Mechanisms of Mediator complex action in transcriptional activation. Cell Mol Life Sci 2013; 70:2743-56. [PMID: 23361037 PMCID: PMC11113466 DOI: 10.1007/s00018-013-1265-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 01/07/2013] [Accepted: 01/09/2013] [Indexed: 12/14/2022]
Abstract
Mediator is a large multisubunit complex that plays a central role in the regulation of RNA Pol II transcribed genes. Conserved in overall structure and function among eukaryotes, Mediator comprises 25-30 protein subunits that reside in four distinct modules, termed head, middle, tail, and CDK8/kinase. Different subunits of Mediator contact other transcriptional regulators including activators, co-activators, general transcription factors, subunits of RNA Pol II, and specifically modified histones, leading to the regulated expression of target genes. This review is focused on the interactions of specific Mediator subunits with diverse transcription regulators and how those interactions contribute to Mediator function in transcriptional activation.
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Affiliation(s)
- Suraiya A. Ansari
- Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12201–0509 USA
| | - Randall H. Morse
- Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12201–0509 USA
- Department of Biomedical Science, University at Albany School of Public Health, Albany, NY USA
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46
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Wang W, Yao X, Huang Y, Hu X, Liu R, Hou D, Chen R, Wang G. Mediator MED23 regulates basal transcription in vivo via an interaction with P-TEFb. Transcription 2013; 4:39-51. [PMID: 23340209 DOI: 10.4161/trns.22874] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The Mediator is a multi-subunit complex that transduces regulatory information from transcription regulators to the RNA polymerase II apparatus. Growing evidence suggests that Mediator plays roles in multiple stages of eukaryotic transcription, including elongation. However, the detailed mechanism by which Mediator regulates elongation remains elusive. In this study, we demonstrate that Mediator MED23 subunit controls a basal level of transcription by recruiting elongation factor P-TEFb, via an interaction with its CDK9 subunit. The mRNA level of Egr1, a MED23-controlled model gene, is reduced 4-5 fold in Med23 (-/-) ES cells under an unstimulated condition, but Med23-deficiency does not alter the occupancies of RNAP II, GTFs, Mediator complex, or activator ELK1 at the Egr1 promoter. Instead, Med23 depletion results in a significant decrease in P-TEFb and RNAP II (Ser2P) binding at the coding region, but no changes for several other elongation regulators, such as DSIF and NELF. ChIP-seq revealed that Med23-deficiency partially reduced the P-TEFb occupancy at a set of MED23-regulated gene promoters. Further, we demonstrate that MED23 interacts with CDK9 in vivo and in vitro. Collectively, these results provide the mechanistic insight into how Mediator promotes RNAP II into transcription elongation.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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47
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High-resolution structure of TBP with TAF1 reveals anchoring patterns in transcriptional regulation. Nat Struct Mol Biol 2013; 20:1008-14. [PMID: 23851461 PMCID: PMC4972576 DOI: 10.1038/nsmb.2611] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 05/14/2013] [Indexed: 02/04/2023]
Abstract
The general transcription factor TFIID provides a regulatory platform for transcription initiation. Here we present the crystal structure (1.97 Å) and NMR analysis of yeast TAF1 N-terminal domains TAND1 and TAND2 when bound to yeast TBP, together with mutational data. The yTAF1-TAND1, which in itself acts as a transcriptional activator, binds into the DNA-binding TBP concave surface by presenting similar anchor residues to TBP as E. coli Mot1 but from a distinct structural scaffold. Furthermore, we show how yTAF1-TAND2 employs an aromatic and acidic anchoring pattern to bind a conserved yTBP surface groove traversing the basic helix region, and we find highly similar TBP-binding motifs also presented by the structurally distinct TFIIA, Mot1 and Brf1 proteins. Our identification of these anchoring patterns, which can be easily disrupted or enhanced, provides compelling insight into the competitive multiprotein TBP interplay critical to transcriptional regulation.
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48
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Mukundan B, Ansari A. Srb5/Med18-mediated termination of transcription is dependent on gene looping. J Biol Chem 2013; 288:11384-94. [PMID: 23476016 PMCID: PMC3630880 DOI: 10.1074/jbc.m112.446773] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/21/2013] [Indexed: 11/06/2022] Open
Abstract
We have earlier demonstrated the involvement of Mediator subunit Srb5/Med18 in the termination of transcription for a subset of genes in yeast. Srb5/Med18 could affect termination either indirectly by modulating CTD-Ser(2) phosphorylation near the 3' end of a gene or directly by physically interacting with the cleavage and polyadenylation factor or cleavage factor 1 (CF1) complex and facilitating their recruitment to the terminator region. Here, we show that the CTD-Ser(2) phosphorylation pattern on Srb5/Med18-dependent genes remains unchanged in the absence of Srb5 in cells. Coimmunoprecipitation analysis revealed the physical interaction of Srb5/Med18 with the CF1 complex. No such interaction of Srb5/Med18 with the cleavage and polyadenylation factor complex, however, could be detected. The Srb5/Med18-CF1 interaction was not observed in the looping defective sua7-1 strain. Srb5/Med18 cross-linking to the 3' end of genes was also abolished in the sua7-1 strain. Chromosome conformation capture analysis revealed that the looped architecture of Srb5/Med18-dependent genes was abrogated in srb5(-) cells. Furthermore, Srb5-dependent termination of transcription was compromised in the looping defective sua7-1 cells. The overall conclusion of these results is that gene looping plays a crucial role in Srb5/Med18 facilitated termination of transcription, and the looped gene architecture may have a general role in termination of transcription in budding yeast.
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Affiliation(s)
- Banupriya Mukundan
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Athar Ansari
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
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49
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Barrero MJ, Malik S. The RNA polymerase II transcriptional machinery and its epigenetic context. Subcell Biochem 2013; 61:237-259. [PMID: 23150254 DOI: 10.1007/978-94-007-4525-4_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
RNA polymerase II (Pol II) is the main engine that drives transcription of protein-encoding genes in eukaryotes. Despite its intrinsic subunit complexity, Pol II is subject to a host of factors that regulate the multistep transcription process. Indeed, the hallmark of the transcription cycle is the dynamic association of Pol II with initiation, elongation and other factors. In addition, Pol II transcription is regulated by a series of cofactors (coactivators and corepressors). Among these, the Mediator has emerged as one of the key regulatory factors for Pol II. Transcription by Pol II takes place in the context of chromatin, which is subject to numerous epigenetic modifications. This chapter mainly summarizes the various biochemical mechanisms that determine formation and function of a Pol II preinitiation complex (PIC) and those that affect its progress along the gene body (elongation). It further examines the various epigenetic modifications that the Pol II machinery encounters, especially in certain developmental contexts, and highlights newer evidence pointing to a likely close interplay between this machinery and factors responsible for the chromatin modifications.
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Affiliation(s)
- Maria J Barrero
- Center for Regenerative Medicine, Dr Aiguader 88, Barcelona, Spain,
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50
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Nock A, Ascano JM, Barrero MJ, Malik S. Mediator-regulated transcription through the +1 nucleosome. Mol Cell 2012; 48:837-48. [PMID: 23159738 DOI: 10.1016/j.molcel.2012.10.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 06/21/2012] [Accepted: 10/09/2012] [Indexed: 10/27/2022]
Abstract
Many genes are regulated at the level of a Pol II that is recruited to a nucleosome-free region upstream of the +1 nucleosome. How the Mediator coactivator complex, which functions at multiple steps, affects transcription through the promoter proximal region, including this nucleosome, remains largely unaddressed. We have established a fully defined in vitro assay system to delineate mechanisms for Pol II transit across the +1 nucleosome. Our results reveal cooperative functions of multiple cofactors, particularly of Mediator and elongation factor SII, in transcribing into this nucleosome. This is achieved, in part, through an unusual activity of SII that alters the intrinsic catalytic properties of promoter-proximal Pol II and, in concert with the Mediator, leads to enhancement in transcription of nucleosomal DNA. Our data provide additional mechanistic bases for Mediator function after recruitment of Pol II and, potentially, for regulation of genes controlled via nucleosome-mediated promoter-proximal pausing.
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Affiliation(s)
- Adam Nock
- Laboratory of Biochemistry and Molecular Biology, Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
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