1
|
Wang Z, Garcia F, Ehlers RU, Molina C. Dauer juvenile recovery transcriptome of two contrasting EMS mutants of the entomopathogenic nematode Heterorhabditis bacteriophora. World J Microbiol Biotechnol 2024; 40:128. [PMID: 38451353 DOI: 10.1007/s11274-024-03902-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/18/2024] [Indexed: 03/08/2024]
Abstract
The entomopathogenic nematode Heterorhabditis bacteriophora, symbiotically associated with enterobacteria of the genus Photorhabdus, is a biological control agent against many insect pests. Dauer Juveniles (DJ) of this nematode are produced in industrial-scale bioreactors up to 100 m3 in liquid culture processes lasting approximately 11 days. A high DJ yield (> 200,000 DJ·mL-1) determines the success of the process. To start the mass production, a DJ inoculum proceeding from a previous monoxenic culture is added to pre-cultured (24 h) Photorhabdus bacteria. Within minutes after contact with the bacteria, DJ are expected to perceive signals that trigger their further development (DJ recovery) to reproductive hermaphrodites. A rapid, synchronized, and high DJ recovery is a key factor for an efficient culture process. In case of low percentage of DJ recovery, the final DJ yield is drastically reduced, and the amount of non-desired stages (males and non-fertilized females) hinders the DJ harvest. In a preliminary work, a huge DJ recovery phenotypic variability in H. bacteriophora ethyl methanesulphonate (EMS) mutants was determined. In the present study, two EMS-mutant lines (M31 and M88) with high and low recovery phenotypes were analyzed concerning their differences in gene expression during the first hours of contact with Photorhabdus supernatant containing food signals triggering recovery. A snapshot (RNA-seq analysis) of their transcriptome was captured at 0.5, 1, 3 and 6 h after exposure. Transcripts (3060) with significant regulation changes were identified in the two lines. To analyze the RNA-seq data over time, we (1) divided the expression profiles into clusters of similar regulation, (2) identified over and under-represented gene ontology categories for each cluster, (3) identified Caenorhabditis elegans homologous genes with recovery-related function, and (4) combined the information with available single nucleotide polymorphism (SNP) data. We observed that the expression dynamics of the contrasting mutants (M31 and M88) differ the most within the first 3 h after Photorhabdus supernatant exposure, and during this time, genes related to changes in the DJ cuticle and molting are more active in the high-recovery line (M31). Comparing the gene expression of DJ exposed to the insect food signal in the haemolymph, genes related to host immunosuppressive factors were not found in DJ upon bacterial supernatant exposure. No link between the position of SNPs associated with high recovery and changes in gene expression was determined for genes with high differential expression. Concerning specific transcripts, nine H. bacteriophora gene models with differential expression are provided as candidate genes for further studies.
Collapse
Affiliation(s)
- Zhen Wang
- e-nema GmbH, Klausdorfer Str. 28-36, 24223, Schwentinental, Germany
- Faculty of Agricultural and Nutritional Sciences, Christian-Albrechts-University Kiel, Hermann-Rodewald-Str. 4, 24118, Kiel, Germany
| | - Francisco Garcia
- e-nema GmbH, Klausdorfer Str. 28-36, 24223, Schwentinental, Germany
- Faculty of Agricultural and Nutritional Sciences, Christian-Albrechts-University Kiel, Hermann-Rodewald-Str. 4, 24118, Kiel, Germany
| | - Ralf-Udo Ehlers
- Faculty of Agricultural and Nutritional Sciences, Christian-Albrechts-University Kiel, Hermann-Rodewald-Str. 4, 24118, Kiel, Germany
| | - Carlos Molina
- e-nema GmbH, Klausdorfer Str. 28-36, 24223, Schwentinental, Germany.
| |
Collapse
|
2
|
Mullan TW, Felton T, Tam J, Kasem O, Yeung TJ, Memar N, Schnabel R, Poole RJ. Control of successive unequal cell divisions by neural cell fate regulators determines embryonic neuroblast cell size. Development 2024; 151:dev200981. [PMID: 38205939 PMCID: PMC10911278 DOI: 10.1242/dev.200981] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 01/02/2024] [Indexed: 01/12/2024]
Abstract
Asymmetric cell divisions often generate daughter cells of unequal size in addition to different fates. In some contexts, daughter cell size asymmetry is thought to be a key input to specific binary cell fate decisions. An alternative possibility is that unequal division is a mechanism by which a variety of cells of different sizes are generated during embryonic development. We show here that two unequal cell divisions precede neuroblast formation in the C lineage of Caenorhabditis elegans. The equalisation of these divisions in a pig-1/MELK mutant background has little effect on neuroblast specification. Instead, we demonstrate that let-19/MDT13 is a regulator of the proneural basic helix-loop-helix transcription factor hlh-14/ASCL1 and find that both are required to concomitantly regulate the acquisition of neuroblast identity and neuroblast cell size. Thus, embryonic neuroblast cell size in this lineage is progressively regulated in parallel with identity by key neural cell fate regulators. We propose that key cell fate determinants have a previously unappreciated function in regulating unequal cleavage, and therefore cell size, of the progenitor cells whose daughter cell fates they then go on to specify.
Collapse
Affiliation(s)
- Thomas W. Mullan
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Terry Felton
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Janis Tam
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Osama Kasem
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Tim J. Yeung
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Nadin Memar
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
- Institut für Genetik, TU Braunschweig, D-38106 Braunschweig, Germany
| | - Ralf Schnabel
- Institut für Genetik, TU Braunschweig, D-38106 Braunschweig, Germany
| | - Richard J. Poole
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| |
Collapse
|
3
|
Liu J, Murray JI. Mechanisms of lineage specification in Caenorhabditis elegans. Genetics 2023; 225:iyad174. [PMID: 37847877 PMCID: PMC11491538 DOI: 10.1093/genetics/iyad174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 09/18/2023] [Indexed: 10/19/2023] Open
Abstract
The studies of cell fate and lineage specification are fundamental to our understanding of the development of multicellular organisms. Caenorhabditis elegans has been one of the premiere systems for studying cell fate specification mechanisms at single cell resolution, due to its transparent nature, the invariant cell lineage, and fixed number of somatic cells. We discuss the general themes and regulatory mechanisms that have emerged from these studies, with a focus on somatic lineages and cell fates. We next review the key factors and pathways that regulate the specification of discrete cells and lineages during embryogenesis and postembryonic development; we focus on transcription factors and include numerous lineage diagrams that depict the expression of key factors that specify embryonic founder cells and postembryonic blast cells, and the diverse somatic cell fates they generate. We end by discussing some future perspectives in cell and lineage specification.
Collapse
Affiliation(s)
- Jun Liu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - John Isaac Murray
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
4
|
Schiano C, Luongo L, Maione S, Napoli C. Mediator complex in neurological disease. Life Sci 2023; 329:121986. [PMID: 37516429 DOI: 10.1016/j.lfs.2023.121986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/18/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Neurological diseases, including traumatic brain injuries, stroke (haemorrhagic and ischemic), and inherent neurodegenerative diseases cause acquired disability in humans, representing a leading cause of death worldwide. The Mediator complex (MED) is a large, evolutionarily conserved multiprotein that facilities the interaction between transcription factors and RNA Polymerase II in eukaryotes. Some MED subunits have been found altered in the brain, although their specific functions in neurodegenerative diseases are not fully understood. Mutations in MED subunits were associated with a wide range of genetic diseases for MED12, MED13, MED13L, MED20, MED23, MED25, and CDK8 genes. In addition, MED12 and MED23 were deregulated in the Alzheimer's Disease. Interestingly, most of the genomic mutations have been found in the subunits of the kinase module. To date, there is only one evidence on MED1 involvement in post-stroke cognitive deficits. Although the underlying neurodegenerative disorders may be different, we are confident that the signal cascades of the biological-cognitive mechanisms of brain adaptation, which begin after brain deterioration, may also differ. Here, we analysed relevant studies in English published up to June 2023. They were identified through a search of electronic databases including PubMed, Medline, EMBASE and Scopus, including search terms such as "Mediator complex", "neurological disease", "brains". Thematic content analysis was conducted to collect and summarize all studies demonstrating MED alteration to understand the role of this central transcriptional regulatory complex in the brain. Improved and deeper knowledge of the regulatory mechanisms in neurological diseases can increase the ability of physicians to predict onset and progression, thereby improving diagnostic care and providing appropriate treatment decisions.
Collapse
Affiliation(s)
- Concetta Schiano
- Department of Advanced Medical and Surgical Sciences (DAMSS), University of Campania "Luigi Vanvitelli", Italy.
| | - Livio Luongo
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Italy; IRCSS, Neuromed, Pozzilli, Italy
| | - Sabatino Maione
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Italy; IRCSS, Neuromed, Pozzilli, Italy
| | - Claudio Napoli
- Department of Advanced Medical and Surgical Sciences (DAMSS), University of Campania "Luigi Vanvitelli", Italy; Clinical Department of Internal Medicine and Specialistic Units, Division of Clinical Immunology and Immunohematology, Transfusion Medicine, and Transplant Immunology (SIMT), Regional Reference Laboratory of Transplant Immunology (LIT), Azienda Universitaria Policlinico (AOU), Italy
| |
Collapse
|
5
|
Agrawal R, Jiří F, Thakur JK. The kinase module of the Mediator complex: an important signalling processor for the development and survival of plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:224-240. [PMID: 32945869 DOI: 10.1093/jxb/eraa439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 09/16/2020] [Indexed: 05/06/2023]
Abstract
Mediator, a multisubunit protein complex, is a signal processor that conveys regulatory information from transcription factors to RNA polymerase II and therefore plays an important role in the regulation of gene expression. This megadalton complex comprises four modules, namely, the head, middle, tail, and kinase modules. The first three modules form the core part of the complex, whereas association of the kinase module is facultative. The kinase module is able to alter the function of Mediator and has been established as a major transcriptional regulator of numerous developmental and biochemical processes. The kinase module consists of MED12, MED13, CycC, and kinase CDK8. Upon association with Mediator, the kinase module can alter its structure and function dramatically. In the past decade, research has established that the kinase module is very important for plant growth and development, and in the fight against biotic and abiotic challenges. However, there has been no comprehensive review discussing these findings in detail and depth. In this review, we survey the regulation of kinase module subunits and highlight their many functions in plants. Coordination between the subunits to process different signals for optimum plant growth and development is also discussed.
Collapse
Affiliation(s)
- Rekha Agrawal
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Fajkus Jiří
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Jitendra K Thakur
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| |
Collapse
|
6
|
Zhou W, Cai H, Li J, Xu H, Wang X, Men H, Zheng Y, Cai L. Potential roles of mediator Complex Subunit 13 in Cardiac Diseases. Int J Biol Sci 2021; 17:328-338. [PMID: 33390853 PMCID: PMC7757031 DOI: 10.7150/ijbs.52290] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 11/25/2020] [Indexed: 12/16/2022] Open
Abstract
Mediator complex subunit 13 (MED13, previously known as THRAP1 and TRAP240) is a subunit of the cyclin-dependent kinase 8 (CDK8) kinase module in the eukaryotic mediator complex. MED13 has been known to play critical roles in cell cycle, development, and growth. The purpose of this review is to comprehensively discuss its newly identified potential roles in myocardial energy metabolism and non-metabolic cardiovascular diseases. Evidence indicates that cardiac MED13 mainly participates in the regulation of nuclear receptor signaling, which drives the transcription of genes involved in modulating cardiac and systemic energy homeostasis. MED13 is also associated with several pathological conditions, such as metabolic syndrome and thyroid disease-associated heart failure. Therefore, MED13 constitutes a potential therapeutic target for the regulation of metabolic disorders and other cardiovascular diseases.
Collapse
Affiliation(s)
- Wenqian Zhou
- The Center of Cardiovascular Diseases, the First Hospital of Jilin University, Changchun 130021, China
- Pediatric Research Institute, the Department of Pediatrics of University of Louisville, Louisville, KY 40202, USA
| | - He Cai
- The Center of Cardiovascular Diseases, the First Hospital of Jilin University, Changchun 130021, China
| | - Jia Li
- Pediatric Research Institute, the Department of Pediatrics of University of Louisville, Louisville, KY 40202, USA
- Department of Nephrology, the First Hospital of Jilin University, Changchun 130021, China
| | - He Xu
- Department of Respiratory Medicine, the First Hospital of Jilin University (Eastern Division), Changchun 130031, China
| | - Xiang Wang
- The Center of Cardiovascular Diseases, the First Hospital of Jilin University, Changchun 130021, China
- Pediatric Research Institute, the Department of Pediatrics of University of Louisville, Louisville, KY 40202, USA
| | - Hongbo Men
- The Center of Cardiovascular Diseases, the First Hospital of Jilin University, Changchun 130021, China
- Pediatric Research Institute, the Department of Pediatrics of University of Louisville, Louisville, KY 40202, USA
| | - Yang Zheng
- The Center of Cardiovascular Diseases, the First Hospital of Jilin University, Changchun 130021, China
| | - Lu Cai
- Pediatric Research Institute, the Department of Pediatrics of University of Louisville, Louisville, KY 40202, USA
- Department of Pharmacology and Toxicology, the University of Louisville, Louisville, KY 40202, USA
| |
Collapse
|
7
|
Söderholm S, Cantù C. The WNT/β‐catenin dependent transcription: A tissue‐specific business. WIREs Mech Dis 2020; 13:e1511. [PMID: 33085215 PMCID: PMC9285942 DOI: 10.1002/wsbm.1511] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 12/11/2022]
Abstract
β‐catenin‐mediated Wnt signaling is an ancient cell‐communication pathway in which β‐catenin drives the expression of certain genes as a consequence of the trigger given by extracellular WNT molecules. The events occurring from signal to transcription are evolutionarily conserved, and their final output orchestrates countless processes during embryonic development and tissue homeostasis. Importantly, a dysfunctional Wnt/β‐catenin pathway causes developmental malformations, and its aberrant activation is the root of several types of cancer. A rich literature describes the multitude of nuclear players that cooperate with β‐catenin to generate a transcriptional program. However, a unified theory of how β‐catenin drives target gene expression is still missing. We will discuss two types of β‐catenin interactors: transcription factors that allow β‐catenin to localize at target regions on the DNA, and transcriptional co‐factors that ultimately activate gene expression. In contrast to the presumed universality of β‐catenin's action, the ensemble of available evidence suggests a view in which β‐catenin drives a complex system of responses in different cells and tissues. A malleable armamentarium of players might interact with β‐catenin in order to activate the right “canonical” targets in each tissue, developmental stage, or disease context. Discovering the mechanism by which each tissue‐specific β‐catenin response is executed will be crucial to comprehend how a seemingly universal pathway fosters a wide spectrum of processes during development and homeostasis. Perhaps more importantly, this could ultimately inform us about which are the tumor‐specific components that need to be targeted to dampen the activity of oncogenic β‐catenin. This article is categorized under:Cancer > Molecular and Cellular Physiology Cancer > Genetics/Genomics/Epigenetics Cancer > Stem Cells and Development
Collapse
Affiliation(s)
- Simon Söderholm
- Wallenberg Centre for Molecular Medicine Linköping University Linköping Sweden
- Department of Biomedical and Clinical Sciences, Division of Molecular Medicine and Virology, Faculty of Health Science Linköping University Linköping Sweden
| | - Claudio Cantù
- Wallenberg Centre for Molecular Medicine Linköping University Linköping Sweden
- Department of Biomedical and Clinical Sciences, Division of Molecular Medicine and Virology, Faculty of Health Science Linköping University Linköping Sweden
| |
Collapse
|
8
|
Besnard F, Picao-Osorio J, Dubois C, Félix MA. A broad mutational target explains a fast rate of phenotypic evolution. eLife 2020; 9:54928. [PMID: 32851977 PMCID: PMC7556874 DOI: 10.7554/elife.54928] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 08/27/2020] [Indexed: 12/30/2022] Open
Abstract
The rapid evolution of a trait in a clade of organisms can be explained by the sustained action of natural selection or by a high mutational variance, that is the propensity to change under spontaneous mutation. The causes for a high mutational variance are still elusive. In some cases, fast evolution depends on the high mutation rate of one or few loci with short tandem repeats. Here, we report on the fastest evolving cell fate among vulva precursor cells in Caenorhabditis nematodes, that of P3.p. We identify and validate causal mutations underlying P3.p's high mutational variance. We find that these positions do not present any characteristics of a high mutation rate, are scattered across the genome and the corresponding genes belong to distinct biological pathways. Our data indicate that a broad mutational target size is the cause of the high mutational variance and of the corresponding fast phenotypic evolutionary rate. Heritable characteristics or traits of a group of organisms, for example the large brain size of primates or the hooves of a horse, are determined by genes, the environment, and by the interactions between them. Traits can change over time and generations when enough mutations in these genes have spread in a species to result in visible differences. However, some traits, such as the large brain of primates, evolve faster than others, but why this is the case has been unclear. It could be that a few specific genes important for that trait in question mutate at a high rate, or, that many genes affect the trait, creating a lot of variation for natural selection to choose from. Here, Besnard, Picao-Osorio et al. studied the roundworm Caenorhabditis elegans to better understand the causes underlying the different rates of trait evolution. These worms have a short life cycle and evolve quickly over many generations, making them an ideal candidate for studying mutation rates in different traits. Previous studies have shown that one of C. elegans’ six cells of the reproductive system evolves faster than the others. To investigate this further, Besnard, Picao-Osorio et al. analysed the genetic mutations driving change in this cell in 250 worm generations. The results showed that five mutations in five different genes – all responsible for different processes in the cells – were behind the supercharged evolution of this particular cell. This suggests that fast evolution results from natural selection acting upon a collection of genes, rather than one gene, and that many genes and pathways shape this trait. In conclusion, these results demonstrate that how traits are coded at the molecular level, in one gene or many, can influence the rate at which they evolve.
Collapse
Affiliation(s)
- Fabrice Besnard
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, Paris, France.,Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, Inria, Lyon, France
| | - Joao Picao-Osorio
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, Paris, France
| | - Clément Dubois
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, Paris, France
| | - Marie-Anne Félix
- Institut de Biologie de l'École Normale Supérieure, CNRS, Inserm, Paris, France
| |
Collapse
|
9
|
Liu Q, Bischof S, Harris CJ, Zhong Z, Zhan L, Nguyen C, Rashoff A, Barshop WD, Sun F, Feng S, Potok M, Gallego-Bartolome J, Zhai J, Wohlschlegel JA, Carey MF, Long JA, Jacobsen SE. The characterization of Mediator 12 and 13 as conditional positive gene regulators in Arabidopsis. Nat Commun 2020; 11:2798. [PMID: 32493925 PMCID: PMC7271234 DOI: 10.1038/s41467-020-16651-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/14/2020] [Indexed: 12/18/2022] Open
Abstract
Mediator 12 (MED12) and MED13 are components of the Mediator multi-protein complex, that facilitates the initial steps of gene transcription. Here, in an Arabidopsis mutant screen, we identify MED12 and MED13 as positive gene regulators, both of which contribute broadly to morc1 de-repressed gene expression. Both MED12 and MED13 are preferentially required for the expression of genes depleted in active chromatin marks, a chromatin signature shared with morc1 re-activated loci. We further discover that MED12 tends to interact with genes that are responsive to environmental stimuli, including light and radiation. We demonstrate that light-induced transient gene expression depends on MED12, and is accompanied by a concomitant increase in MED12 enrichment during induction. In contrast, the steady-state expression level of these genes show little dependence on MED12, suggesting that MED12 is primarily required to aid the expression of genes in transition from less-active to more active states. Mediator is a multiprotein complex required to activate gene transcription by RNAPII. Here, the authors report that MED12 and MED13 are conditional positive regulators that facilitate the expression of genes depleted in active chromatin marks and the induction of gene expression in response to environmental stimuli in Arabidopsis.
Collapse
Affiliation(s)
- Qikun Liu
- School of Advanced Agricultural Sciences, Peking University, 100871, Beijing, China. .,Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA.
| | - Sylvain Bischof
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA.,Department of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
| | - C Jake Harris
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Zhenhui Zhong
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA.,Basic Forestry and Proteomics Center, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Lingyu Zhan
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Calvin Nguyen
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Andrew Rashoff
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - William D Barshop
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Fei Sun
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Suhua Feng
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Magdalena Potok
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Javier Gallego-Bartolome
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Jixian Zhai
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Michael F Carey
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Jeffrey A Long
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Steven E Jacobsen
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA. .,Howard Hughes Medical Institute, University of California at Los Angeles, Los Angeles, CA, 90095, USA.
| |
Collapse
|
10
|
Wang Z, Yang Y, Xiong W, Zhou R, Song N, Liu L, Qian J. Dexmedetomidine protects H9C2 against hypoxia/reoxygenation injury through miR-208b-3p/Med13/Wnt signaling pathway axis. Biomed Pharmacother 2020; 125:110001. [PMID: 32070878 DOI: 10.1016/j.biopha.2020.110001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 01/22/2023] Open
Abstract
Dexmedetomidine (Dex) has been reported to be cardioprotective. Differential expression of miR-208b-3p is associated with myocardial injury. But it is unknown that aberrant expression of miR-208b-3p is implicated in myocardial protection of Dex. Hypoxia/reoxygenation (HR) model was established in H9C2 cells. qRT-PCR was performed to detect expression levels of miR-208b-3p in H9C2 undergoing HR, Dex preconditioning, overexpression of miR-208b-3p or inhibition, and to assess expression of Med13 in H9C2 following knockdown of Med13 mRNA. CCK8 and, flow cytometry and Western blot were conducted respectively to examine viability, apoptosis rate and protein expressions of H9C2 subjected to a variety of treatments. Dex preconditioning reduced expression of miR-208b-3p and apoptosis of H9C2 cells caused by HR, while Dex preconditioning increased viability of H9C2. Dex preconditioning increased expression of Med13, which was reduced after knockdown of Med13 mRNA in H9C2. Overexpression of miR-208b-3p attenuated Dex exerted protective effects of myocardial cells, which was reversed by inhibition of miR-208b-3p. Increased expression of Med13 or/and decreased expression of miR-208b-3p decreased expression levels of Wnt/β-catenin signaling pathway-related proteins (Wnt3a, Wnt5a and β-catenin), while knockdown of Med13 mRNA or increased expression of miR-208b-3p increased the expression levels of those proteins. Dex protects H9C2 cells against HR injury through miR-208b-3p/Med13/Wnt/β-catenin signaling pathway axis.
Collapse
Affiliation(s)
- Zhuoran Wang
- Department of Anesthesiology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China
| | - Yuqiao Yang
- Department of Anesthesiology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China
| | - Wei Xiong
- Department of Anesthesiology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China
| | - Rui Zhou
- Department of Anesthesiology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China
| | - Ning Song
- Department of Anesthesiology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China
| | - Lan Liu
- Department of Pathology, Kunming Medical University, Kunming, Yunnan Province, China
| | - Jinqiao Qian
- Department of Anesthesiology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China.
| |
Collapse
|
11
|
Zhao Y, Dong S, Kong Y, Rui Q, Wang D. Molecular basis of intestinal canonical Wnt/β-catenin BAR-1 in response to simulated microgravity in Caenorhabditis elegans. Biochem Biophys Res Commun 2020; 522:198-204. [DOI: 10.1016/j.bbrc.2019.11.082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 11/14/2019] [Indexed: 12/29/2022]
|
12
|
Li X, Liu M, Ji JY. Understanding Obesity as a Risk Factor for Uterine Tumors Using Drosophila. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1167:129-155. [PMID: 31520353 DOI: 10.1007/978-3-030-23629-8_8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multiple large-scale epidemiological studies have identified obesity as an important risk factor for a variety of human cancers, particularly cancers of the uterus, gallbladder, kidney, liver, colon, and ovary, but there is much uncertainty regarding how obesity increases the cancer risks. Given that obesity has been consistently identified as a major risk factor for uterine tumors, the most common malignancies of the female reproductive system, we use uterine tumors as a pathological context to survey the relevant literature and propose a novel hypothesis: chronic downregulation of the cyclin-dependent kinase 8 (CDK8) module, composed of CDK8 (or its paralog CDK19), Cyclin C, MED12 (or MED12L), and MED13 (or MED13L), by elevated insulin or insulin-like growth factor signaling in obese women may increase the chances to dysregulate the activities of transcription factors regulated by the CDK8 module, thereby increasing the risk of uterine tumors. Although we focus on endometrial cancer and uterine leiomyomas (or fibroids), two major forms of uterine tumors, our model may offer additional insights into how obesity increases the risk of other types of cancers and diseases. To illustrate the power of model organisms for studying human diseases, here we place more emphasis on the findings obtained from Drosophila melanogaster.
Collapse
Affiliation(s)
- Xiao Li
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, USA
| | - Mengmeng Liu
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, USA
| | - Jun-Yuan Ji
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, USA.
| |
Collapse
|
13
|
Abstract
Transcriptional control of oxytocinergic cell development influences social, sexual, and appetite related behaviors and is implicated in disorders such as autism and Prader-Willi syndrome. Mediator 12 (Med12) is a transcriptional coactivator required for multiple facets of brain development including subsets of serotonergic and dopaminergic neurons. We surveyed hormone gene expression within the hypothalamo-pituitary axis of med12 mutant zebrafish embryos with a focus on oxytocin (oxt) expression. Some transcripts, such as oxt, vasopressin (avp) and corticotrophin releasing hormone (crh) are undetectable in the med12 mutant, while others are upregulated or downregulated to varying degrees. In med12 mutants, the expression patterns of upstream transcriptional regulators of oxytocinergic cell development remain largely intact in the pre-optic area, suggesting a more direct influence of Med12 on oxt expression. We show that Med12 is required for Wnt signaling in zebrafish. However, oxt expression is unaffected in Wnt-inhibited embryos indicating independence of Wnt signaling. In fact, overactive Wnt signaling inhibits oxt expression, and we identify a Wnt-sensitive period starting at 24 h post fertilization (hpf). Thus, Med12 and repression of Wnt signaling display critical but unrelated roles in regulating oxt expression. Summary: Mediator 12, a transcriptional coactivator, greatly enhances Wnt signaling in the developing embryo. Separate from its role in Wnt signaling, Mediator 12 is required for oxytocin expression.
Collapse
Affiliation(s)
- Emma D Spikol
- Department of Oncology, Georgetown University, 4000 Reservoir Rd., Washington, DC 20057, USA
| | - Eric Glasgow
- Department of Oncology, Georgetown University, 4000 Reservoir Rd., Washington, DC 20057, USA
| |
Collapse
|
14
|
Doitsidou M, Minevich G, Kroll JR, Soete G, Gowtham S, Korswagen HC, Sebastiaan van Zon J, Hobert O. A Caenorhabditis elegans Zinc Finger Transcription Factor, ztf-6, Required for the Specification of a Dopamine Neuron-Producing Lineage. G3 (BETHESDA, MD.) 2018; 8:17-26. [PMID: 29301976 PMCID: PMC5765345 DOI: 10.1534/g3.117.300132] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 10/31/2017] [Indexed: 12/12/2022]
Abstract
Invertebrate and vertebrate nervous systems generate different types of dopaminergic neurons in distinct parts of the brain. We have taken a genetic approach to understand how the four functionally related, but lineally unrelated, classes of dopaminergic neurons of the nematode Caenorhabditis elegans, located in distinct parts of its nervous system, are specified. We have identified several genes involved in the generation of a specific dopaminergic neuron type that is generated from the so-called postdeirid lineage, called PDE. Apart from classic proneural genes and components of the mediator complex, we identified a novel, previously uncharacterized zinc finger transcription factor, ztf-6 Loss of ztf-6 has distinct effects in different dopamine neuron-producing neuronal lineages. In the postdeirid lineage, ztf-6 is required for proper cell division patterns and the proper distribution of a critical cell fate determinant, the POP-1/TCF-like transcription factor.
Collapse
Affiliation(s)
- Maria Doitsidou
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center New York, NY 10032
- Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD, UK
| | - Gregory Minevich
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center New York, NY 10032
| | - Jason R Kroll
- AMOLF, Amsterdam, 1098 XG, The Netherlands, 3584 CT Utrecht, The Netherlands
| | - Gwen Soete
- Hubrecht Institute, 3584 CT Utrecht, The Netherlands
| | - Sriharsh Gowtham
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center New York, NY 10032
| | | | | | - Oliver Hobert
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center New York, NY 10032
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027
| |
Collapse
|
15
|
Donnio LM, Bidon B, Hashimoto S, May M, Epanchintsev A, Ryan C, Allen W, Hackett A, Gecz J, Skinner C, Stevenson RE, de Brouwer APM, Coutton C, Francannet C, Jouk PS, Schwartz CE, Egly JM. MED12-related XLID disorders are dose-dependent of immediate early genes (IEGs) expression. Hum Mol Genet 2017; 26:2062-2075. [PMID: 28369444 DOI: 10.1093/hmg/ddx099] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/08/2017] [Indexed: 11/13/2022] Open
Abstract
Mediator occupies a key role in protein coding genes expression in mediating the contacts between gene specific factors and the basal transcription machinery but little is known regarding the role of each Mediator subunits. Mutations in MED12 are linked with a broad spectrum of genetic disorders with X-linked intellectual disability that are difficult to range as Lujan, Opitz-Kaveggia or Ohdo syndromes. Here, we investigated several MED12 patients mutations (p.R206Q, p.N898D, p.R961W, p.N1007S, p.R1148H, p.S1165P and p.R1295H) and show that each MED12 mutations cause specific expression patterns of JUN, FOS and EGR1 immediate early genes (IEGs), reflected by the presence or absence of MED12 containing complex at their respective promoters. Moreover, the effect of MED12 mutations has cell-type specificity on IEG expression. As a consequence, the expression of late responsive genes such as the matrix metalloproteinase-3 and the RE1 silencing transcription factor implicated respectively in neural plasticity and the specific expression of neuronal genes is disturbed as documented for MED12/p.R1295H mutation. In such case, JUN and FOS failed to be properly recruited at their AP1-binding site. Our results suggest that the differences between MED12-related phenotypes are essentially the result of distinct IEGs expression patterns, the later ones depending on the accurate formation of the transcription initiation complex. This might challenge clinicians to rethink the traditional syndromes boundaries and to include genetic criterion in patients' diagnostic.
Collapse
Affiliation(s)
- Lise-Marie Donnio
- Department of Functional Genomics and Cancer biology, IGBMC, CNRS/INSERM/Université de Strasbourg, 67404 Illkirch-Graffenstaden, France
| | - Baptiste Bidon
- Department of Functional Genomics and Cancer biology, IGBMC, CNRS/INSERM/Université de Strasbourg, 67404 Illkirch-Graffenstaden, France
| | - Satoru Hashimoto
- Department of Functional Genomics and Cancer biology, IGBMC, CNRS/INSERM/Université de Strasbourg, 67404 Illkirch-Graffenstaden, France.,Department of Clinical Pharmacology and Therapeutics Oita University Faculty of Medicine, Yufu city, Oita 879-5593, Japan
| | - Melanie May
- Greenwood Genetic Center, Greenwood, SC 29649, USA
| | - Alexey Epanchintsev
- Department of Functional Genomics and Cancer biology, IGBMC, CNRS/INSERM/Université de Strasbourg, 67404 Illkirch-Graffenstaden, France
| | - Colm Ryan
- Department of Functional Genomics and Cancer biology, IGBMC, CNRS/INSERM/Université de Strasbourg, 67404 Illkirch-Graffenstaden, France
| | | | | | - Jozef Gecz
- School of Medicine, and the Robinson Research Institute, The University of Adelaide, and South Australian Health and Medical Research Institute, Adelaide, SA 5000, Australia
| | | | | | - Arjan P M de Brouwer
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, 6525?HP, The Netherlands
| | - Charles Coutton
- Département de Génétique et Procréation, Centre Hospitalier-Universitaire, Institut Albert Bonniot, CNRS/INSERM/Université Grenoble Alpes, 38000 Grenoble, France
| | - Christine Francannet
- Service de Génétique Médicale, Centre Hospitalier-Universitaire, 63003 Clermont-Ferrand, France
| | - Pierre-Simon Jouk
- Département de Génétique et Procréation, Centre Hospitalier-Universitaire, Institut Albert Bonniot, CNRS/INSERM/Université Grenoble Alpes, 38000 Grenoble, France
| | | | - Jean-Marc Egly
- Department of Functional Genomics and Cancer biology, IGBMC, CNRS/INSERM/Université de Strasbourg, 67404 Illkirch-Graffenstaden, France
| |
Collapse
|
16
|
Raya-González J, López-Bucio JS, Prado-Rodríguez JC, Ruiz-Herrera LF, Guevara-García ÁA, López-Bucio J. The MEDIATOR genes MED12 and MED13 control Arabidopsis root system configuration influencing sugar and auxin responses. PLANT MOLECULAR BIOLOGY 2017; 95:141-156. [PMID: 28780645 DOI: 10.1007/s11103-017-0647-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 07/27/2017] [Indexed: 05/23/2023]
Abstract
Arabidopsis med12 and med13 mutants exhibit shoot and root phenotypes related to an altered auxin homeostasis. Sucrose supplementation reactivates both cell division and elongation in primary roots as well as auxin-responsive and stem cell niche gene expression in these mutants. An analysis of primary root growth of WT, med12, aux1-7 and med12 aux1 single and double mutants in response to sucrose and/or N-1-naphthylphthalamic acid (NPA) placed MED12 upstream of auxin transport for the sugar modulation of root growth. The MEDIATOR (MED) complex plays diverse functions in plant development, hormone signaling and biotic and abiotic stress tolerance through coordination of transcription. Here, we performed genetic, developmental, molecular and pharmacological analyses to characterize the role of MED12 and MED13 on the configuration of root architecture and its relationship with auxin and sugar responses. Arabidopsis med12 and med13 single mutants exhibit shoot and root phenotypes consistent with altered auxin homeostasis including altered primary root growth, lateral root development, and root hair elongation. MED12 and MED13 were required for activation of cell division and elongation in primary roots, as well as auxin-responsive and stem cell niche gene expression. Remarkably, most of these mutant phenotypes were rescued by supplying sucrose to the growth medium. The growth response of primary roots of WT, med12, aux1-7 and med12 aux1 single and double mutants to sucrose and application of auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) revealed the correlation of med12 phenotype with the activity of the auxin intake permease and suggests that MED12 acts upstream of AUX1 in the root growth response to sugar. These data provide compelling evidence that MEDIATOR links sugar sensing to auxin transport and distribution during root morphogenesis.
Collapse
Affiliation(s)
- Javier Raya-González
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacán, Mexico
| | | | - José Carlos Prado-Rodríguez
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacán, Mexico
| | - León Francisco Ruiz-Herrera
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacán, Mexico
| | | | - José López-Bucio
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacán, Mexico.
| |
Collapse
|
17
|
Baskin KK, Makarewich CA, DeLeon SM, Ye W, Chen B, Beetz N, Schrewe H, Bassel-Duby R, Olson EN. MED12 regulates a transcriptional network of calcium-handling genes in the heart. JCI Insight 2017; 2:91920. [PMID: 28724790 DOI: 10.1172/jci.insight.91920] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 06/13/2017] [Indexed: 02/06/2023] Open
Abstract
The Mediator complex regulates gene transcription by linking basal transcriptional machinery with DNA-bound transcription factors. The activity of the Mediator complex is mainly controlled by a kinase submodule that is composed of 4 proteins, including MED12. Although ubiquitously expressed, Mediator subunits can differentially regulate gene expression in a tissue-specific manner. Here, we report that MED12 is required for normal cardiac function, such that mice with conditional cardiac-specific deletion of MED12 display progressive dilated cardiomyopathy. Loss of MED12 perturbs expression of calcium-handling genes in the heart, consequently altering calcium cycling in cardiomyocytes and disrupting cardiac electrical activity. We identified transcription factors that regulate expression of calcium-handling genes that are downregulated in the heart in the absence of MED12, and we found that MED12 localizes to transcription factor consensus sequences within calcium-handling genes. We showed that MED12 interacts with one such transcription factor, MEF2, in cardiomyocytes and that MED12 and MEF2 co-occupy promoters of calcium-handling genes. Furthermore, we demonstrated that MED12 enhances MEF2 transcriptional activity and that overexpression of both increases expression of calcium-handling genes in cardiomyocytes. Our data support a role for MED12 as a coordinator of transcription through MEF2 and other transcription factors. We conclude that MED12 is a regulator of a network of calcium-handling genes, consequently mediating contractility in the mammalian heart.
Collapse
Affiliation(s)
| | | | | | | | - Beibei Chen
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | - Heinrich Schrewe
- Department of Developmental Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Rhonda Bassel-Duby
- Department of Molecular Biology and.,Hamon Center for Regenerative Science and Medicine and.,Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Eric N Olson
- Department of Molecular Biology and.,Hamon Center for Regenerative Science and Medicine and.,Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| |
Collapse
|
18
|
Asadollahi R, Zweier M, Gogoll L, Schiffmann R, Sticht H, Steindl K, Rauch A. Genotype-phenotype evaluation of MED13L defects in the light of a novel truncating and a recurrent missense mutation. Eur J Med Genet 2017. [PMID: 28645799 DOI: 10.1016/j.ejmg.2017.06.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A decade after the designation of MED13L as a gene and its link to intellectual disability (ID) and dextro-looped transposition of great arteries in 2003, we previously described a recognizable syndrome due to MED13L haploinsufficiency. Subsequent reports of 22 further patients diagnosed by genome-wide testing further delineated the syndrome with expansion of the phenotypic spectrum and showed reduced penetrance for congenital heart defects. We now report two novel patients identified by whole exome sequencing, one with a de novo MED13L truncating mutation and the other with a de novo missense mutation. The first patient indicates some facial resemblance to Kleefstra syndrome as a novel differential diagnosis, and the second patient shows, for the first time, recurrence of a MED13L missense mutation (p.(Asp860Gly)). Notably, our in silico modelling predicted this missense mutation to decrease the stability of an alpha-helix and thereby affecting the MED13L secondary structure, while the majority of published missense mutations remain variants of uncertain significance. Review of the reported patients with MED13L haploinsufficiency indicates moderate to severe ID and facial anomalies in all patients, as well as severe speech delay and muscular hypotonia in the majority. Further common signs include abnormal MRI findings of myelination defects and abnormal corpus callosum, ataxia and coordination problems, autistic features, seizures/abnormal EEG, or congenital heart defects, present in about 20-50% of the patients. With reference to facial anomalies, the majority of patients were reported to show broad/prominent forehead, low set ears, bitemporal narrowing, upslanting palpebral fissures, depressed/flat nasal bridge, bulbous nose, and abnormal chin, but macroglossia and horizontal eyebrows were also observed in ∼30%. The latter are especially important in the differential diagnosis of 1p36 deletion and Kleefstra syndromes, while the more common facial gestalt shows some resemblance to 22q11.2 deletion syndrome. Despite the fact that MED13L was found to be one of the most common ID genes in the Deciphering Developmental Disorders Study, further detailed patient descriptions are needed to explore the full clinical spectrum, potential genotype-phenotype correlations, as well as the role of missense mutations and potential mutational hotspots along the gene.
Collapse
Affiliation(s)
- Reza Asadollahi
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Markus Zweier
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Laura Gogoll
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Raphael Schiffmann
- Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, TX, USA
| | - Heinrich Sticht
- Institute of Biochemistry, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland; Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
| |
Collapse
|
19
|
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: 1.9] [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
| |
Collapse
|
20
|
Aberrant expression of CDK8 regulates the malignant phenotype and associated with poor prognosis in human laryngeal squamous cell carcinoma. Eur Arch Otorhinolaryngol 2017; 274:2205-2213. [DOI: 10.1007/s00405-017-4484-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 01/24/2017] [Indexed: 10/20/2022]
|
21
|
Lam AK, Phillips BT. Wnt Signaling Polarizes C. elegans Asymmetric Cell Divisions During Development. Results Probl Cell Differ 2017; 61:83-114. [PMID: 28409301 PMCID: PMC6057142 DOI: 10.1007/978-3-319-53150-2_4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Asymmetric cell division is a common mode of cell differentiation during the invariant lineage of the nematode, C. elegans. Beginning at the four-cell stage, and continuing throughout embryogenesis and larval development, mother cells are polarized by Wnt ligands, causing an asymmetric inheritance of key members of a Wnt/β-catenin signal transduction pathway termed the Wnt/β-catenin asymmetry pathway. The resulting daughter cells are distinct at birth with one daughter cell activating Wnt target gene expression via β-catenin activation of TCF, while the other daughter displays transcriptional repression of these target genes. Here, we seek to review the body of evidence underlying a unified model for Wnt-driven asymmetric cell division in C. elegans, identify global themes that occur during asymmetric cell division, as well as highlight tissue-specific variations. We also discuss outstanding questions that remain unanswered regarding this intriguing mode of asymmetric cell division.
Collapse
Affiliation(s)
- Arielle Koonyee Lam
- Interdisciplinary Graduate Program in Molecular and Cellular Biology, University of Iowa, Iowa City, IA, USA
| | | |
Collapse
|
22
|
Buendía-Monreal M, Gillmor CS. Mediator: A key regulator of plant development. Dev Biol 2016; 419:7-18. [PMID: 27287881 DOI: 10.1016/j.ydbio.2016.06.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 06/01/2016] [Accepted: 06/06/2016] [Indexed: 10/21/2022]
Abstract
Mediator is a multiprotein complex that regulates transcription at the level of RNA pol II assembly, as well as through regulation of chromatin architecture, RNA processing and recruitment of epigenetic marks. Though its modular structure is conserved in eukaryotes, its subunit composition has diverged during evolution and varies in response to environmental and tissue-specific inputs, suggesting different functions for each subunit and/or Mediator conformation. In animals, Mediator has been implicated in the control of differentiation and morphogenesis through modulation of numerous signaling pathways. In plants, studies have revealed roles for Mediator in regulation of cell division, cell fate and organogenesis, as well as developmental timing and hormone responses. We begin this review with an overview of biochemical mechanisms of yeast and animal Mediator that are likely to be conserved in all eukaryotes, as well as a brief discussion of the role of Mediator in animal development. We then present a comprehensive review of studies of the role of Mediator in plant development. Finally, we point to important questions for future research on the role of Mediator as a master coordinator of development.
Collapse
Affiliation(s)
- Manuel Buendía-Monreal
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, CINVESTAV-IPN, Irapuato, Guanajuato, Mexico
| | - C Stewart Gillmor
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, CINVESTAV-IPN, Irapuato, Guanajuato, Mexico.
| |
Collapse
|
23
|
The Mediator Kinase Module Restrains Epidermal Growth Factor Receptor Signaling and Represses Vulval Cell Fate Specification in Caenorhabditis elegans. Genetics 2015; 202:583-99. [PMID: 26715664 DOI: 10.1534/genetics.115.180265] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 12/18/2015] [Indexed: 12/27/2022] Open
Abstract
Cell signaling pathways that control proliferation and determine cell fates are tightly regulated to prevent developmental anomalies and cancer. Transcription factors and coregulators are important effectors of signaling pathway output, as they regulate downstream gene programs. In Caenorhabditis elegans, several subunits of the Mediator transcriptional coregulator complex promote or inhibit vulva development, but pertinent mechanisms are poorly defined. Here, we show that Mediator's dissociable cyclin dependent kinase 8 (CDK8) module (CKM), consisting of cdk-8, cic-1/Cyclin C, mdt-12/dpy-22, and mdt-13/let-19, is required to inhibit ectopic vulval cell fates downstream of the epidermal growth factor receptor (EGFR)-Ras-extracellular signal-regulated kinase (ERK) pathway. cdk-8 inhibits ectopic vulva formation by acting downstream of mpk-1/ERK, cell autonomously in vulval cells, and in a kinase-dependent manner. We also provide evidence that the CKM acts as a corepressor for the Ets-family transcription factor LIN-1, as cdk-8 promotes transcriptional repression by LIN-1. In addition, we find that CKM mutation alters Mediator subunit requirements in vulva development: the mdt-23/sur-2 subunit, which is required for vulva development in wild-type worms, is dispensable for ectopic vulva formation in CKM mutants, which instead display hallmarks of unrestrained Mediator tail module activity. We propose a model whereby the CKM controls EGFR-Ras-ERK transcriptional output by corepressing LIN-1 and by fine tuning Mediator specificity, thus balancing transcriptional repression vs. activation in a critical developmental signaling pathway. Collectively, these data offer an explanation for CKM repression of EGFR signaling output and ectopic vulva formation and provide the first evidence of Mediator CKM-tail module subunit crosstalk in animals.
Collapse
|
24
|
McCleland ML, Soukup TM, Liu SD, Esensten JH, de Sousa e Melo F, Yaylaoglu M, Warming S, Roose-Girma M, Firestein R. Cdk8 deletion in the Apc(Min) murine tumour model represses EZH2 activity and accelerates tumourigenesis. J Pathol 2015; 237:508-19. [PMID: 26235356 DOI: 10.1002/path.4596] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 07/09/2015] [Accepted: 07/28/2015] [Indexed: 01/29/2023]
Abstract
CDK8 is a dissociable kinase module of the Mediator complex and has been shown to play an important role in transcriptional regulation in organisms as diverse as yeast and humans. Recent studies suggest that CDK8 functions as an oncoprotein in melanoma and colon cancer. Importantly, these studies were conducted using in vitro cell line models and the role of CDK8 in tumourigenesis in vivo has not been explored. We have generated a mouse with a Cdk8 conditional knockout allele and examined the consequences of Cdk8 loss on normal tissue homeostasis and tumour development in vivo. Cdk8 deletion in the young adult mouse did not induce any gross or histopathological abnormalities, implying that Cdk8 is largely dispensable for somatic cellular homeostasis. In contrast, Cdk8 deletion in the Apc(Min) intestinal tumour model shortened the animals' survival and increased tumour burden. Although Cdk8 deletion did not affect tumour initiation, intestinal tumour size and growth rate were significantly increased in Cdk8-null animals. Transcriptome analysis performed on Cdk8-null intestinal cells revealed up-regulation of genes that are governed by the Polycomb group (PcG) complex. In support of these findings, Cdk8-null intestinal cells and tumours displayed a reduction in histone H3K27 trimethylation, both globally and at the promoters of a number of PcG-regulated genes involved in oncogenic signalling. Together, our findings uncover a tumour suppressor function for CDK8 in vivo and suggest that the role of CDK8 activity in driving oncogenesis is context-specific. Sequencing data were deposited at GEO (Accession No. GSE71385).
Collapse
Affiliation(s)
- Mark L McCleland
- Department of Pathology, Genentech Inc, South San Francisco, CA, USA
| | - Tim M Soukup
- Department of Molecular Biology, Genentech Inc, South San Francisco, CA, USA
| | - Scot D Liu
- Department of Pathology, Genentech Inc, South San Francisco, CA, USA
| | | | | | - Murat Yaylaoglu
- Department of Pathology, Genentech Inc, South San Francisco, CA, USA
| | - Soren Warming
- Department of Molecular Biology, Genentech Inc, South San Francisco, CA, USA
| | - Merone Roose-Girma
- Department of Molecular Biology, Genentech Inc, South San Francisco, CA, USA
| | - Ron Firestein
- Department of Pathology, Genentech Inc, South San Francisco, CA, USA
| |
Collapse
|
25
|
Clark AD, Oldenbroek M, Boyer TG. Mediator kinase module and human tumorigenesis. Crit Rev Biochem Mol Biol 2015; 50:393-426. [PMID: 26182352 DOI: 10.3109/10409238.2015.1064854] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mediator is a conserved multi-subunit signal processor through which regulatory informatiosn conveyed by gene-specific transcription factors is transduced to RNA Polymerase II (Pol II). In humans, MED13, MED12, CDK8 and Cyclin C (CycC) comprise a four-subunit "kinase" module that exists in variable association with a 26-subunit Mediator core. Genetic and biochemical studies have established the Mediator kinase module as a major ingress of developmental and oncogenic signaling through Mediator, and much of its function in signal-dependent gene regulation derives from its resident CDK8 kinase activity. For example, CDK8-targeted substrate phosphorylation impacts transcription factor half-life, Pol II activity and chromatin chemistry and functional status. Recent structural and biochemical studies have revealed a precise network of physical and functional subunit interactions required for proper kinase module activity. Accordingly, pathologic change in this activity through altered expression or mutation of constituent kinase module subunits can have profound consequences for altered signaling and tumor formation. Herein, we review the structural organization, biological function and oncogenic potential of the Mediator kinase module. We focus principally on tumor-associated alterations in kinase module subunits for which mechanistic relationships as opposed to strictly correlative associations are established. These considerations point to an emerging picture of the Mediator kinase module as an oncogenic unit, one in which pathogenic activation/deactivation through component change drives tumor formation through perturbation of signal-dependent gene regulation. It follows that therapeutic strategies to combat CDK8-driven tumors will involve targeted modulation of CDK8 activity or pharmacologic manipulation of dysregulated CDK8-dependent signaling pathways.
Collapse
Affiliation(s)
- Alison D Clark
- a Department of Molecular Medicine , Institute of Biotechnology, University of Texas Health Science Center at San Antonio , San Antonio , TX , USA
| | - Marieke Oldenbroek
- a Department of Molecular Medicine , Institute of Biotechnology, University of Texas Health Science Center at San Antonio , San Antonio , TX , USA
| | - Thomas G Boyer
- a Department of Molecular Medicine , Institute of Biotechnology, University of Texas Health Science Center at San Antonio , San Antonio , TX , USA
| |
Collapse
|
26
|
Grants JM, Goh GYS, Taubert S. The Mediator complex of Caenorhabditis elegans: insights into the developmental and physiological roles of a conserved transcriptional coregulator. Nucleic Acids Res 2015; 43:2442-53. [PMID: 25634893 PMCID: PMC4344494 DOI: 10.1093/nar/gkv037] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Mediator multiprotein complex (‘Mediator’) is an important transcriptional coregulator that is evolutionarily conserved throughout eukaryotes. Although some Mediator subunits are essential for the transcription of all protein-coding genes, others influence the expression of only subsets of genes and participate selectively in cellular signaling pathways. Here, we review the current knowledge of Mediator subunit function in the nematode Caenorhabditis elegans, a metazoan in which established and emerging genetic technologies facilitate the study of developmental and physiological regulation in vivo. In this nematode, unbiased genetic screens have revealed critical roles for Mediator components in core developmental pathways such as epidermal growth factor (EGF) and Wnt/β-catenin signaling. More recently, important roles for C. elegans Mediator subunits have emerged in the regulation of lipid metabolism and of systemic stress responses, engaging conserved transcription factors such as nuclear hormone receptors (NHRs). We emphasize instances where similar functions for individual Mediator subunits exist in mammals, highlighting parallels between Mediator subunit action in nematode development and in human cancer biology. We also discuss a parallel between the association of the Mediator subunit MED12 with several human disorders and the role of its C. elegans ortholog mdt-12 as a regulatory hub that interacts with numerous signaling pathways.
Collapse
Affiliation(s)
- Jennifer M Grants
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada Centre for Molecular Medicine and Therapeutics, Child & Family Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Grace Y S Goh
- Centre for Molecular Medicine and Therapeutics, Child & Family Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada Graduate Program in Cell and Developmental Biology, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Stefan Taubert
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada Centre for Molecular Medicine and Therapeutics, Child & Family Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada Graduate Program in Cell and Developmental Biology, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| |
Collapse
|
27
|
Gillmor CS, Silva-Ortega CO, Willmann MR, Buendía-Monreal M, Poethig RS. The Arabidopsis Mediator CDK8 module genes CCT (MED12) and GCT (MED13) are global regulators of developmental phase transitions. Development 2014; 141:4580-9. [PMID: 25377553 DOI: 10.1242/dev.111229] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Temporal coordination of developmental programs is necessary for normal ontogeny, but the mechanism by which this is accomplished is still poorly understood. We have previously shown that two components of the Mediator CDK8 module encoded by CENTER CITY (CCT; Arabidopsis MED12) and GRAND CENTRAL (GCT; Arabidopsis MED13) are required for timing of pattern formation during embryogenesis. A morphological, molecular and genomic analysis of the post-embryonic phenotype of gct and cct mutants demonstrated that these genes also promote at least three subsequent developmental transitions: germination, vegetative phase change, and flowering. Genetic and molecular analyses indicate that GCT and CCT operate in parallel to gibberellic acid, a phytohormone known to regulate these same three transitions. We demonstrate that the delay in vegetative phase change in gct and cct is largely due to overexpression of miR156, and that the delay in flowering is due in part to upregulation of FLC. Thus, GCT and CCT coordinate vegetative and floral transitions by repressing the repressors miR156 and FLC. Our results suggest that MED12 and MED13 act as global regulators of developmental timing by fine-tuning the expression of temporal regulatory genes.
Collapse
Affiliation(s)
- C Stewart Gillmor
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, 36821, Mexico Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Claudia O Silva-Ortega
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, 36821, Mexico
| | - Matthew R Willmann
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Manuel Buendía-Monreal
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, 36821, Mexico
| | - R Scott Poethig
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
28
|
Arai E, Sakamoto H, Ichikawa H, Totsuka H, Chiku S, Gotoh M, Mori T, Nakatani T, Ohnami S, Nakagawa T, Fujimoto H, Wang L, Aburatani H, Yoshida T, Kanai Y. Multilayer-omics analysis of renal cell carcinoma, including the whole exome, methylome and transcriptome. Int J Cancer 2014; 135:1330-42. [PMID: 24504440 PMCID: PMC4235299 DOI: 10.1002/ijc.28768] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 01/16/2014] [Indexed: 12/22/2022]
Abstract
The aim of this study was to identify pathways that have a significant impact during renal carcinogenesis. Sixty-seven paired samples of both noncancerous renal cortex tissue and cancerous tissue from patients with clear cell renal cell carcinomas (RCCs) were subjected to whole-exome, methylome and transcriptome analyses using Agilent SureSelect All Exon capture followed by sequencing on an Illumina HiSeq 2000 platform, Illumina Infinium HumanMethylation27 BeadArray and Agilent SurePrint Human Gene Expression microarray, respectively. Sanger sequencing and quantitative reverse transcription-PCR were performed for technical verification. MetaCore software was used for pathway analysis. Somatic nonsynonymous single-nucleotide mutations, insertions/deletions and intragenic breaks of 2,153, 359 and 8 genes were detected, respectively. Mutations of GCN1L1, MED12 and CCNC, which are members of CDK8 mediator complex directly regulating β-catenin-driven transcription, were identified in 16% of the RCCs. Mutations of MACF1, which functions in the Wnt/β-catenin signaling pathway, were identified in 4% of the RCCs. A combination of methylome and transcriptome analyses further highlighted the significant role of the Wnt/β-catenin signaling pathway in renal carcinogenesis. Genetic aberrations and reduced expression of ERC2 and ABCA13 were frequent in RCCs, and MTOR mutations were identified as one of the major disrupters of cell signaling during renal carcinogenesis. Our results confirm that multilayer-omics analysis can be a powerful tool for revealing pathways that play a significant role in carcinogenesis.
Collapse
Affiliation(s)
- Eri Arai
- Division of Molecular Pathology, National Cancer Center Research Institute, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Yin JW, Wang G. The Mediator complex: a master coordinator of transcription and cell lineage development. Development 2014; 141:977-87. [PMID: 24550107 DOI: 10.1242/dev.098392] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mediator is a multiprotein complex that is required for gene transcription by RNA polymerase II. Multiple subunits of the complex show specificity in relaying information from signals and transcription factors to the RNA polymerase II machinery, thus enabling control of the expression of specific genes. Recent studies have also provided novel mechanistic insights into the roles of Mediator in epigenetic regulation, transcriptional elongation, termination, mRNA processing, noncoding RNA activation and super enhancer formation. Based on these specific roles in gene regulation, Mediator has emerged as a master coordinator of development and cell lineage determination. Here, we describe the most recent advances in understanding the mechanisms of Mediator function, with an emphasis on its role during development and disease.
Collapse
Affiliation(s)
- Jing-wen Yin
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | | |
Collapse
|
30
|
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.
Collapse
Affiliation(s)
- Zachary C Poss
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, CO , USA
| | | | | |
Collapse
|
31
|
Steimel A, Suh J, Hussainkhel A, Deheshi S, Grants JM, Zapf R, Moerman DG, Taubert S, Hutter H. The C. elegans CDK8 Mediator module regulates axon guidance decisions in the ventral nerve cord and during dorsal axon navigation. Dev Biol 2013; 377:385-98. [PMID: 23458898 DOI: 10.1016/j.ydbio.2013.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 01/21/2013] [Accepted: 02/14/2013] [Indexed: 11/30/2022]
Abstract
Receptors expressed on the growth cone of outgrowing axons detect cues required for proper navigation. The pathway choices available to an axon are in part defined by the set of guidance receptors present on the growth cone. Regulated expression of receptors and genes controlling the localization and activity of receptors ensures that axons respond only to guidance cues relevant for reaching their targets. In genetic screens for axon guidance mutants, we isolated an allele of let-19/mdt-13, a component of the Mediator, a large ~30 subunit protein complex essential for gene transcription by RNA polymerase II. LET-19/MDT-13 is part of the CDK8 module of the Mediator. By testing other Mediator components, we found that all subunits of the CDK8 module as well as some other Mediator components are required for specific axon navigation decisions in a subset of neurons. Expression profiling demonstrated that let-19/mdt-13 regulates the expression of a large number of genes in interneurons. A mutation in the sax-3 gene, encoding a receptor for the repulsive guidance cue SLT-1, suppresses the commissure navigation defects found in cdk-8 mutants. This suggests that the CDK8 module specifically represses the SAX-3/ROBO pathway to ensure proper commissure navigation.
Collapse
Affiliation(s)
- Andreas Steimel
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Gow M, Mirembe D, Longwe Z, Pickard BS. A gene trap mutagenesis screen for genes underlying cellular response to the mood stabilizer lithium. J Cell Mol Med 2013; 17:657-63. [PMID: 23577691 PMCID: PMC3822818 DOI: 10.1111/jcmm.12048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 01/31/2013] [Indexed: 01/16/2023] Open
Abstract
Identifying the biological pathways mediating the action of a therapeutic compound may help the development of more specific treatments while also increasing our understanding of the underlying disease pathology. Salts of the metal lithium are commonly used as a front-line mood stabilizing treatment for bipolar disorder. Lithium's action has been variously linked to inositol phosphate metabolism and the WNT/Glycogen Synthase Kinase 3β (GSK3β)/β-Catenin signalling cascade, but, to date, little is known about which of these provides the principal therapeutic benefit for patients and, more specifically, which constituent genes, through presumed sequence variation, determine differences in patient response to treatment. Here, we describe a functional screen in which SH-SY5Y neuroblastoma cells were randomly mutated through genomic integration of the pMS1 poly A ‘gene trap’ plasmid vector. Lithium normally induces differentiation of neuroblastoma cells, but a small proportion of mutated cells continued to proliferate and formed colonies. Rapid amplification of cDNA ends (RACE)-PCR was used to identify the ‘trapped’ gene in each of these lithium-resistant colonies. Heterozygous, gene trap integrations were identified within ten genes, eight of which are likely to produce loss-of-function mutations including MED10, MSI2 and three long intergenic non-coding (LINC) RNAs. Both MED10 and MSI2 have been previously linked with WNT/GSK3β/β-Catenin pathway function suggesting that this is an important mediator of lithium action in this screen. The methodology applied here provides a rapid, objective and economic approach to define the genetic contribution to drug action, but could also be readily adapted to any desired in vitro functional selection/screening paradigm.
Collapse
Affiliation(s)
- Matthew Gow
- Undergraduate Biomedical Sciences Honours Degree Programmes, University of Strathclyde, Glasgow, UK
| | | | | | | |
Collapse
|
33
|
Asadollahi R, Oneda B, Sheth F, Azzarello-Burri S, Baldinger R, Joset P, Latal B, Knirsch W, Desai S, Baumer A, Houge G, Andrieux J, Rauch A. Dosage changes of MED13L further delineate its role in congenital heart defects and intellectual disability. Eur J Hum Genet 2013; 21:1100-4. [PMID: 23403903 DOI: 10.1038/ejhg.2013.17] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/09/2013] [Accepted: 01/16/2013] [Indexed: 01/20/2023] Open
Abstract
A chromosomal balanced translocation disrupting the MED13L (Mediator complex subunit13-like) gene, encoding a subunit of the Mediator complex, was previously associated with transposition of the great arteries (TGA) and intellectual disability (ID), and led to the identification of missense mutations in three patients with isolated TGA. Recently, a homozygous missense mutation in MED13L was found in two siblings with non-syndromic ID from a consanguineous family. Here, we describe for the first time, three patients with copy number changes affecting MED13L and delineate a recognizable MED13L haploinsufficiency syndrome. Using high resolution molecular karyotyping, we identified two intragenic de novo frameshift deletions, likely resulting in haploinsufficiency, in two patients with a similar phenotype of hypotonia, moderate ID, conotruncal heart defect and facial anomalies. In both, Sanger sequencing of MED13L did not reveal any pathogenic mutation and exome sequencing in one patient showed no evidence for a non-allelic second hit. A further patient with hypotonia, learning difficulties and perimembranous VSD showed a 1 Mb de novo triplication in 12q24.2, including MED13L and MAP1LC3B2. Our findings show that MED13L haploinsufficiency in contrast to the previously observed missense mutations cause a distinct syndromic phenotype. Additionally, a MED13L copy number gain results in a milder phenotype. The clinical features suggesting a neurocristopathy may be explained by animal model studies indicating involvement of the Mediator complex subunit 13 in neural crest induction.
Collapse
Affiliation(s)
- Reza Asadollahi
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Chen Y, Dong Y, Sandiford S, Dimopoulos G. Transcriptional mediators Kto and Skd are involved in the regulation of the IMD pathway and anti-Plasmodium defense in Anopheles gambiae. PLoS One 2012; 7:e45580. [PMID: 23049816 PMCID: PMC3458077 DOI: 10.1371/journal.pone.0045580] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 08/22/2012] [Indexed: 01/30/2023] Open
Abstract
The malarial parasite Plasmodium must complete a complex lifecycle in its Anopheles mosquito host, the main vector for Plasmodium. The mosquito resists infection with the human malarial parasite P. falciparum by engaging the NF-κB immune signaling pathway, IMD. Here we show that the conserved transcriptional mediators Kto and Skd are involved in the regulation of the mosquito IMD pathway. RNAi-mediated depletion of Kto and Skd in the Anopheles gambiae cell line L5-3 resulted in a decrease in the transcript abundance of Cec1, which is controlled by the IMD pathway. Silencing the two genes also resulted in an increased susceptibility of the mosquito to bacterial and Plasmodium falciparum infection, but not to infection with the rodent malaria parasite P. berghei. We also showed that Kto and Skd are not transcriptional co-activators of Rel2 or other key factors of the IMD pathway; however, they participate in the regulation of the IMD pathway, which is crucial for the mosquito’s defense against P. falciparum.
Collapse
Affiliation(s)
- Yang Chen
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Yuemei Dong
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Simone Sandiford
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
| |
Collapse
|
35
|
Murray JI, Boyle TJ, Preston E, Vafeados D, Mericle B, Weisdepp P, Zhao Z, Bao Z, Boeck M, Waterston RH. Multidimensional regulation of gene expression in the C. elegans embryo. Genome Res 2012; 22:1282-94. [PMID: 22508763 PMCID: PMC3396369 DOI: 10.1101/gr.131920.111] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
How cells adopt different expression patterns is a fundamental question of developmental biology. We quantitatively measured reporter expression of 127 genes, primarily transcription factors, in every cell and with high temporal resolution in C. elegans embryos. Embryonic cells are highly distinct in their gene expression; expression of the 127 genes studied here can distinguish nearly all pairs of cells, even between cells of the same tissue type. We observed recurrent lineage-regulated expression patterns for many genes in diverse contexts. These patterns are regulated in part by the TCF-LEF transcription factor POP-1. Other genes' reporters exhibited patterns correlated with tissue, position, and left–right asymmetry. Sequential patterns both within tissues and series of sublineages suggest regulatory pathways. Expression patterns often differ between embryonic and larval stages for the same genes, emphasizing the importance of profiling expression in different stages. This work greatly expands the number of genes in each of these categories and provides the first large-scale, digitally based, cellular resolution compendium of gene expression dynamics in live animals. The resulting data sets will be a useful resource for future research.
Collapse
Affiliation(s)
- John Isaac Murray
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Imura Y, Kobayashi Y, Yamamoto S, Furutani M, Tasaka M, Abe M, Araki T. CRYPTIC PRECOCIOUS/MED12 is a novel flowering regulator with multiple target steps in Arabidopsis. PLANT & CELL PHYSIOLOGY 2012; 53:287-303. [PMID: 22247249 PMCID: PMC3278046 DOI: 10.1093/pcp/pcs002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 01/05/2012] [Indexed: 05/22/2023]
Abstract
The proper timing of flowering is of crucial importance for reproductive success of plants. Regulation of flowering is orchestrated by inputs from both environmental and endogenous signals such as daylength, light quality, temperature and hormones, and key flowering regulators construct several parallel and interactive genetic pathways. This integrative regulatory network has been proposed to create robustness as well as plasticity of the regulation. Although knowledge of key genes and their regulation has been accumulated, there still remains much to learn about how they are organized into an integrative regulatory network. Here, we have analyzed the CRYPTIC PRECOCIOUS (CRP) gene for the Arabidopsis counterpart of the MED12 subunit of the Mediator. A novel dominant mutant, crp-1D, which causes up-regulation of SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), FRUITFULL (FUL) and APETALA1 (AP1) expression in a FLOWERING LOCUS T (FT)-dependent manner, was identified in an enhancer screen of the early-flowering phenotype of 35S::FT. Genetic and molecular analysis of both crp-1D and crp loss-of-function alleles showed that MED12/CRP is required not only for proper regulation of SOC1, FUL and AP1, but also for up-regulation of FT, TWIN SISTER OF FT (TSF) and FD, and down-regulation of FLOWERING LOCUS C (FLC). These observations suggest that MED12/CRP is a novel flowering regulator with multiple regulatory target steps both upstream and downstream of the key flowering regulators including FT florigen. Our work, taken together with recent studies of other Mediator subunit genes, supports an emerging view that the Mediator plays multiple roles in the regulation of flowering.
Collapse
Affiliation(s)
- Yuri Imura
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan
| | - Yasushi Kobayashi
- Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Sumiko Yamamoto
- Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
- Genome Informatics Laboratory, CIB-DDBJ, National Institute of Genetics, ROIS, Shizuoka, 411-8540 Japan
| | - Masahiko Furutani
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0101 Japan
| | - Masao Tasaka
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0101 Japan
| | - Mitsutomo Abe
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033 Japan
| | - Takashi Araki
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan
- *Corresponding author: E-mail, ; Fax, +81-75-753-6470.
| |
Collapse
|
37
|
Abstract
Wnts are conserved, secreted signaling proteins that can influence cell behavior by stabilizing β-catenin. Accumulated β-catenin enters the nucleus, where it physically associates with T-cell factor (TCF) family members to regulate target gene expression in many developmental and adult tissues. Recruitment of β-catenin to Wnt response element (WRE) chromatin converts TCFs from transcriptional repressors to activators. This review will outline the complex interplay between factors contributing to TCF repression and coactivators working with β-catenin to regulate Wnt targets. In addition, three variations of the standard transcriptional switch model will be discussed. One is the Wnt/β-catenin symmetry pathway in Caenorhabditis elegans, where Wnt-mediated nuclear efflux of TCF is crucial for activation of targets. Another occurs in vertebrates, where distinct TCF family members are associated with repression and activation, and recent evidence suggests that Wnt signaling facilitates a "TCF exchange" on WRE chromatin. Finally, a "reverse switch" mechanism for target genes that are directly repressed by Wnt/β-catenin signaling occurs in Drosophila cells. The diversity of TCF regulatory mechanisms may help to explain how a small group of transcription factors can function in so many different contexts to regulate target gene expression.
Collapse
Affiliation(s)
- Ken M Cadigan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| |
Collapse
|
38
|
Xu W, Ji JY. Dysregulation of CDK8 and Cyclin C in tumorigenesis. J Genet Genomics 2011; 38:439-52. [PMID: 22035865 PMCID: PMC9792140 DOI: 10.1016/j.jgg.2011.09.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 09/05/2011] [Accepted: 09/06/2011] [Indexed: 01/23/2023]
Abstract
Appropriately controlled gene expression is fundamental for normal growth and survival of all living organisms. In eukaryotes, the transcription of protein-coding mRNAs is dependent on RNA polymerase II (Pol II). The multi-subunit transcription cofactor Mediator complex is proposed to regulate most, if not all, of the Pol II-dependent transcription. Here we focus our discussion on two subunits of the Mediator complex, cyclin-dependent kinase 8 (CDK8) and its regulatory partner Cyclin C (CycC), because they are either mutated or amplified in a variety of human cancers. CDK8 functions as an oncoprotein in melanoma and colorectal cancers, thus there are considerable interests in developing drugs specifically targeting the CDK8 kinase activity. However, to evaluate the feasibility of targeting CDK8 for cancer therapy and to understand how their dysregulation contributes to tumorigenesis, it is essential to elucidate the in vivo function and regulation of CDK8-CycC, which are still poorly understood in multi-cellular organisms. We summarize the evidence linking their dysregulation to various cancers and present our bioinformatics and computational analyses on the structure and evolution of CDK8. We also discuss the implications of these observations in tumorigenesis. Because most of the Mediator subunits, including CDK8 and CycC, are highly conserved during eukaryotic evolution, we expect that investigations using model organisms such as Drosophila will provide important insights into the function and regulation of CDK8 and CycC in different cellular and developmental contexts.
Collapse
Affiliation(s)
- Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, P.O. Box 44370, Lafayette, LA 70504, USA
| | - Jun-Yuan Ji
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Science Center, College Station, TX 77843, USA
- Corresponding author: Tel: +1 979 845 6389, fax: +1 979 847 9481. (J.-Y. Ji)
| |
Collapse
|
39
|
Hentges KE. Mediator complex proteins are required for diverse developmental processes. Semin Cell Dev Biol 2011; 22:769-75. [PMID: 21854862 DOI: 10.1016/j.semcdb.2011.07.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 07/19/2011] [Accepted: 07/20/2011] [Indexed: 12/14/2022]
Abstract
The Mediator complex serves a crucial function in gene regulation, forming a link between gene-specific transcription factors and RNA polymerase II. Most protein-coding genes therefore require Mediator complex activity for transcriptional regulation. Given the essential functions performed by Mediator complex proteins in gene regulation, it is not surprising that mutations in Mediator complex genes disrupt animal and plant development. What is more intriguing is that the phenotypes of individual Mediator complex mutants are distinct from each other, demonstrating that certain developmental processes have a greater requirement for specific Mediator complex genes. Additionally, the range of developmental processes that are altered in Mediator complex mutants is broad, affecting a variety of cell types and physiological systems. Gene expression defects in Mediator complex mutants reveal distinct roles for individual Mediator proteins in transcriptional regulation, suggesting that the deletion of one Mediator complex protein does not interfere with transcription in general, but instead alters the expression of specific target genes. Mediator complex proteins may have diverse roles in different organisms as well, as mutants in the same Mediator gene in different species can display dissimilar phenotypes.
Collapse
Affiliation(s)
- Kathryn E Hentges
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
| |
Collapse
|
40
|
Boeck ME, Boyle T, Bao Z, Murray J, Mericle B, Waterston R. Specific roles for the GATA transcription factors end-1 and end-3 during C. elegans E-lineage development. Dev Biol 2011; 358:345-55. [PMID: 21854766 DOI: 10.1016/j.ydbio.2011.08.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 08/02/2011] [Accepted: 08/03/2011] [Indexed: 12/21/2022]
Abstract
end-1 and end-3 are GATA transcription factors important for specifying endoderm cell fate in Caenorhabditis elegans. Deletion of both factors together results in larval arrest, 0% survival and a fate change in the endoderm-specifying E lineage. Individual deletions of either factor, however, result in the development of viable, fertile adults, with 100% of worms developing to adults for end-1(-) and 95% for end-3(-). We sought to quantify the variable phenotypes seen in both deletions using automated cell lineaging. We quantified defects in cell lifetime, cell movement and division axis in end-3(-) embryos, while quantifying perturbations in downstream reporter gene expression in strains with homozygous deletions for either gene, showing that each deletion leads to a unique profile of downstream perturbations in gene expression and cellular phenotypes with a high correlation between early and late defects. Combining observations in both cellular and gene expression defects we found that misaligned divisions at the E2 stage resulted in ectopic expression of the Notch target ref-1 in end-3(-) embryos. Using a maximum likelihood phylogenetic approach we found end-1 and end-3 split to form two distinct clades within the Caenorhabditis lineage with distinct DNA-binding structures. These results indicate that end-1 and end-3 have each evolved into genes with unique functions during endoderm development, that end-3(-) embryos have a delay in the onset of E lineage cell fate and that end-1 has only a partially penetrant ability to activate E lineage fate.
Collapse
Affiliation(s)
- Max E Boeck
- Department of Genome Sciences, University of Washington School of Medicine, 1705 NE Pacific Street, Seattle, WA 98195, USA.
| | | | | | | | | | | |
Collapse
|
41
|
Ito J, Sono T, Tasaka M, Furutani M. MACCHI-BOU 2 is required for early embryo patterning and cotyledon organogenesis in Arabidopsis. PLANT & CELL PHYSIOLOGY 2011; 52:539-552. [PMID: 21257604 DOI: 10.1093/pcp/pcr013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The phytohormone auxin is a key regulator of organogenesis in plants and is distributed asymmetrically via polar transport. However, the precise mechanisms underlying auxin-mediated organogenesis remain elusive. Here, we have analyzed the macchi-bou 2 (mab2) mutant identified in a pinoid (pid) enhancer mutant screen. Seedlings homozygous for either mab2 or pid showed only mild phenotypic effects on cotyledon positions and/or numbers. In contrast, mab2 pid double mutant seedlings completely lacked cotyledons, indicating a synergistic interaction. We found that mab2 homozygous embryos had defective patterns of cell division and showed aberrant cotyledon organogenesis. Further analysis revealed that the mab2 mutation affected auxin response but not auxin transport in the embryos, suggesting the involvement of MAB2 in auxin response during embryogenesis. MAB2 encodes an Arabidopsis ortholog of MED13, a putative regulatory module component of the Mediator complex. Mediator is a multicomponent complex that is evolutionarily conserved in eukaryotes and its regulatory module associates with Mediator to control the interaction of Mediator and RNA polymerase II. MAB2 interacts with a regulatory module component in yeast cells. Taken together, our data suggest that MAB2 plays a crucial role in embryo patterning and cotyledon organogenesis, possibly through modulating expression of specific genes such as auxin-responsive genes.
Collapse
Affiliation(s)
- Jun Ito
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0101 Japan
| | | | | | | |
Collapse
|
42
|
De Smet I, Beeckman T. Asymmetric cell division in land plants and algae: the driving force for differentiation. Nat Rev Mol Cell Biol 2011; 12:177-88. [PMID: 21346731 DOI: 10.1038/nrm3064] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Asymmetric cell division generates two cells with different fates and has an important role in plant development. It produces distinct cell types and new organs, and maintains stem cell niches. To handle the constraints of having immobile cells, plants possess numerous unique features to obtain asymmetry, such as specific regulators of intrinsic polarity. Although several components have not yet been identified, new findings, together with knowledge from different developmental systems, now allow us to take an important step towards a mechanistic overview of asymmetric cell division in plants and algae. Strikingly, several key regulators are used for different developmental processes, and common mechanisms can be recognized.
Collapse
Affiliation(s)
- Ive De Smet
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK.
| | | |
Collapse
|
43
|
Greene DM, Bloomfield G, Skelton J, Ivens A, Pears CJ. Targets downstream of Cdk8 in Dictyostelium development. BMC DEVELOPMENTAL BIOLOGY 2011; 11:2. [PMID: 21255384 PMCID: PMC3037916 DOI: 10.1186/1471-213x-11-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 01/21/2011] [Indexed: 11/11/2022]
Abstract
Background Cdk8 is a component of the mediator complex which facilitates transcription by RNA polymerase II and has been shown to play an important role in development of Dictyostelium discoideum. This eukaryote feeds as single cells but starvation triggers the formation of a multicellular organism in response to extracellular pulses of cAMP and the eventual generation of spores. Strains in which the gene encoding Cdk8 have been disrupted fail to form multicellular aggregates unless supplied with exogenous pulses of cAMP and later in development, cdk8- cells show a defect in spore production. Results Microarray analysis revealed that the cdk8- strain previously described (cdk8-HL) contained genome duplications. Regeneration of the strain in a background lacking detectable gene duplication generated strains (cdk8-2) with identical defects in growth and early development, but a milder defect in spore generation, suggesting that the severity of this defect depends on the genetic background. The failure of cdk8- cells to aggregate unless rescued by exogenous pulses of cAMP is consistent with a failure to express the catalytic subunit of protein kinase A. However, overexpression of the gene encoding this protein was not sufficient to rescue the defect, suggesting that this is not the only important target for Cdk8 at this stage of development. Proteomic analysis revealed two potential targets for Cdk8 regulation, one regulated post-transcriptionally (4-hydroxyphenylpyruvate dioxygenase (HPD)) and one transcriptionally (short chain dehydrogenase/reductase (SDR1)). Conclusions This analysis has confirmed the importance of Cdk8 at multiple stages of Dictyostelium development, although the severity of the defect in spore production depends on the genetic background. Potential targets of Cdk8-mediated gene regulation have been identified in Dictyostelium which will allow the mechanism of Cdk8 action and its role in development to be determined.
Collapse
Affiliation(s)
- David M Greene
- Biochemistry Department, Oxford University, South Parks Road, Oxford OX1 3QU UK.
| | | | | | | | | |
Collapse
|
44
|
Gaudet J, McGhee JD. Recent advances in understanding the molecular mechanisms regulating C. elegans transcription. Dev Dyn 2010; 239:1388-404. [PMID: 20175193 DOI: 10.1002/dvdy.22246] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
We review recent studies that have advanced our understanding of the molecular mechanisms regulating transcription in the nematode C. elegans. Topics covered include: (i) general properties of C. elegans promoters; (ii) transcription factors and transcription factor combinations involved in cell fate specification and cell differentiation; (iii) new roles for general transcription factors; (iv) nucleosome positioning in C. elegans "chromatin"; and (v) some characteristics of histone variants and histone modifications and their possible roles in controlling C. elegans transcription.
Collapse
Affiliation(s)
- Jeb Gaudet
- Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute for Child and Maternal Health, University of Calgary, Calgary, Alberta, Canada
| | | |
Collapse
|
45
|
Control of cyclin C levels during development of Dictyostelium. PLoS One 2010; 5:e10543. [PMID: 20479885 PMCID: PMC2866538 DOI: 10.1371/journal.pone.0010543] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 04/16/2010] [Indexed: 11/19/2022] Open
Abstract
Background Cdk8 and its partner cyclin C form part of the mediator complex which links the basal transcription machinery to regulatory proteins. The pair are required for correct regulation of a subset of genes and have been implicated in control of development in a number of organisms including the social amoeba Dictyostelium discoideum. When feeding, Dictyostelium amoebae are unicellular but upon starvation they aggregate to form a multicellular structure which develops into a fruiting body containing spores. Cells in which the gene encoding Cdk8 has been deleted fail to enter aggregates due to a failure of early gene expression. Principal Findings We have monitored the expression levels of cyclin C protein during development and find levels decrease after the multicellular mound is formed. This decrease is triggered by extracellular cAMP that, in turn, is working in part through an increase in intracellular cAMP. The loss of cyclin C is coincident with a reduction in the association of Cdk8 with a high molecular weight complex in the nucleus. Overexpression of cyclin C and Cdk8 lead to an increased rate of early development, consistent with the levels being rate limiting. Conclusions Overall these results show that both cyclin C and Cdk8 are regulated during development in response to extracellular signals and the levels of these proteins are important in controlling the timing of developmental processes. These findings have important implications for the role of these proteins in controlling development, suggesting that they are targets for developmental signals to regulate gene expression.
Collapse
|
46
|
Gillmor CS, Park MY, Smith MR, Pepitone R, Kerstetter RA, Poethig RS. The MED12-MED13 module of Mediator regulates the timing of embryo patterning in Arabidopsis. Development 2010; 137:113-22. [PMID: 20023166 DOI: 10.1242/dev.043174] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The Arabidopsis embryo becomes patterned into central and peripheral domains during the first few days after fertilization. A screen for mutants that affect this process identified two genes, GRAND CENTRAL (GCT)and CENTER CITY (CCT). Mutations in GCT and CCT delay the specification of central and peripheral identity and the globular-to-heart transition, but have little or no effect on the initial growth rate of the embryo. Mutant embryos eventually recover and undergo relatively normal patterning, albeit at an inappropriate size. GCT and CCT were identified as the Arabidopsis orthologs of MED13 and MED12 - evolutionarily conserved proteins that act in association with the Mediator complex to negatively regulate transcription. The predicted function of these proteins combined with the effect of gct and cct on embryo development suggests that MED13 and MED12 regulate pattern formation during Arabidopsis embryogenesis by transiently repressing a transcriptional program that interferes with this process. Their mutant phenotype reveals the existence of a previously unknown temporal regulatory mechanism in plant embryogenesis.
Collapse
Affiliation(s)
- C Stewart Gillmor
- Department of Biological Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | | | |
Collapse
|
47
|
Abstract
The Wnt/beta-catenin pathway plays an important role in initiation in most, if not all, colon cancers. Prior work has provided important insights into the regulation of beta-catenin stability in the cytoplasm; however, relatively little is known about the mechanism by which beta-catenin activates gene transcription in the nucleus. Using genetic approaches, studies in human colon cancers and Drosophila have identified CDK8 as a colon cancer oncogene that regulates beta-catenin transcriptional activity. These convergent observations provide new insights into the regulation of nuclear beta-catenin activity and identify a novel therapeutic target for beta-catenin-driven malignancies.
Collapse
Affiliation(s)
- Ron Firestein
- Department of Medical Oncology, Dana-Farber Cancer Institute, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
48
|
Voutev R, Keating R, Hubbard EJA, Vallier LG. Characterization of the Caenorhabditis elegans Islet LIM-homeodomain ortholog, lim-7. FEBS Lett 2009; 583:456-64. [PMID: 19116151 PMCID: PMC2719984 DOI: 10.1016/j.febslet.2008.12.046] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 12/16/2008] [Indexed: 11/29/2022]
Abstract
lim-7 is one of seven Caenorhabditis elegans LIM-homeodomain (LIM-HD)-encoding genes and the sole Islet ortholog. LIM-HD transcription factors, including Islets, function in neuronal and non-neuronal development across diverse phyla. Our results show that a lim-7 deletion allele causes early larval lethality with terminal phenotypes including uncoordination, detached pharynx, constipation and morphological defects. A lim-7(+) transgene rescues lethality but not adult sterility. A lim-7(+) reporter in the full genomic context is expressed in all gonadal sheath cells, URA neurons, and additional cells in the pharyngeal region. Finally, we identify a 45-bp regulatory element in the first intron that is necessary and sufficient for lim-7 gonadal sheath expression.
Collapse
Affiliation(s)
- Roumen Voutev
- Developmental Genetics Program, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, United States
| | | | | | | |
Collapse
|
49
|
Lowery LA, De Rienzo G, Gutzman JH, Sive H. Characterization and classification of zebrafish brain morphology mutants. Anat Rec (Hoboken) 2009; 292:94-106. [PMID: 19051268 PMCID: PMC2894611 DOI: 10.1002/ar.20768] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mechanisms by which the vertebrate brain achieves its three-dimensional structure are clearly complex, requiring the functions of many genes. Using the zebrafish as a model, we have begun to define genes required for brain morphogenesis, including brain ventricle formation, by studying 16 mutants previously identified as having embryonic brain morphology defects. We report the phenotypic characterization of these mutants at several timepoints, using brain ventricle dye injection, imaging, and immunohistochemistry with neuronal markers. Most of these mutants display early phenotypes, affecting initial brain shaping, whereas others show later phenotypes, affecting brain ventricle expansion. In the early phenotype group, we further define four phenotypic classes and corresponding functions required for brain morphogenesis. Although we did not use known genotypes for this classification, basing it solely on phenotypes, many mutants with defects in functionally related genes clustered in a single class. In particular, Class 1 mutants show midline separation defects, corresponding to epithelial junction defects; Class 2 mutants show reduced brain ventricle size; Class 3 mutants show midbrain-hindbrain abnormalities, corresponding to basement membrane defects; and Class 4 mutants show absence of ventricle lumen inflation, corresponding to defective ion pumping. Later brain ventricle expansion requires the extracellular matrix, cardiovascular circulation, and transcription/splicing-dependent events. We suggest that these mutants define processes likely to be used during brain morphogenesis throughout the vertebrates. Anat Rec, 2009. (c) 2008 Wiley-Liss, Inc.
Collapse
Affiliation(s)
- Laura Anne Lowery
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge MA 02142
- Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Gianluca De Rienzo
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge MA 02142
| | - Jennifer H. Gutzman
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge MA 02142
| | - Hazel Sive
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge MA 02142
- Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139
| |
Collapse
|
50
|
The human CDK8 subcomplex is a histone kinase that requires Med12 for activity and can function independently of mediator. Mol Cell Biol 2008; 29:650-61. [PMID: 19047373 DOI: 10.1128/mcb.00993-08] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The four proteins CDK8, cyclin C, Med12, and Med13 can associate with Mediator and are presumed to form a stable "CDK8 subcomplex" in cells. We describe here the isolation and enzymatic activity of the 600-kDa CDK8 subcomplex purified directly from human cells and also via recombinant expression in insect cells. Biochemical analysis of the recombinant CDK8 subcomplex identifies predicted (TFIIH and RNA polymerase II C-terminal domain [Pol II CTD]) and novel (histone H3, Med13, and CDK8 itself) substrates for the CDK8 kinase. Notably, these novel substrates appear to be metazoan-specific. Such diverse targets imply strict regulation of CDK8 kinase activity. Along these lines, we observe that Mediator itself enables CDK8 kinase activity on chromatin, and we identify Med12--but not Med13--to be essential for activating the CDK8 kinase. Moreover, mass spectrometry analysis of the endogenous CDK8 subcomplex reveals several associated factors, including GCN1L1 and the TRiC chaperonin, that may help control its biological function. In support of this, electron microscopy analysis suggests TRiC sequesters the CDK8 subcomplex and kinase assays reveal the endogenous CDK8 subcomplex--unlike the recombinant submodule--is unable to phosphorylate the Pol II CTD.
Collapse
|