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Cummins-Beebee PN, Chvilicek MM, Rothenfluh A. The Stage-Based Model of Addiction-Using Drosophila to Investigate Alcohol and Psychostimulant Responses. Int J Mol Sci 2023; 24:10909. [PMID: 37446084 PMCID: PMC10341944 DOI: 10.3390/ijms241310909] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/23/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Addiction is a progressive and complex disease that encompasses a wide range of disorders and symptoms, including substance use disorder (SUD), for which there are few therapeutic treatments. SUD is the uncontrolled and chronic use of substances despite the negative consequences resulting from this use. The progressive nature of addiction is organized into a testable framework, the neurobiological stage-based model, that includes three behavioral stages: (1) binge/intoxication, (2) withdrawal/negative affect, and (3) preoccupation/anticipation. Human studies offer limited opportunities for mechanistic insights into these; therefore, model organisms, like Drosophila melanogaster, are necessary for understanding SUD. Drosophila is a powerful model organism that displays a variety of SUD-like behaviors consistent with human and mammalian substance use, making flies a great candidate to study mechanisms of behavior. Additionally, there are an abundance of genetic tools like the GAL4/UAS and CRISPR/Cas9 systems that can be used to gain insight into the molecular mechanisms underlying the endophenotypes of the three-stage model. This review uses the three-stage framework and discusses how easily testable endophenotypes have been examined with experiments using Drosophila, and it outlines their potential for investigating other endophenotypes.
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Affiliation(s)
- Pearl N. Cummins-Beebee
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Neuroscience Graduate Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Maggie M. Chvilicek
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Neuroscience Graduate Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Adrian Rothenfluh
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Neuroscience Graduate Program, University of Utah, Salt Lake City, UT 84112, USA
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84112, USA
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
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2
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Consolidation and maintenance of long-term memory involve dual functions of the developmental regulator Apterous in clock neurons and mushroom bodies in the Drosophila brain. PLoS Biol 2021; 19:e3001459. [PMID: 34860826 PMCID: PMC8641882 DOI: 10.1371/journal.pbio.3001459] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 10/25/2021] [Indexed: 11/23/2022] Open
Abstract
Memory is initially labile but can be consolidated into stable long-term memory (LTM) that is stored in the brain for extended periods. Despite recent progress, the molecular and cellular mechanisms underlying the intriguing neurobiological processes of LTM remain incompletely understood. Using the Drosophila courtship conditioning assay as a memory paradigm, here, we show that the LIM homeodomain (LIM-HD) transcription factor Apterous (Ap), which is known to regulate various developmental events, is required for both the consolidation and maintenance of LTM. Interestingly, Ap is involved in these 2 memory processes through distinct mechanisms in different neuronal subsets in the adult brain. Ap and its cofactor Chip (Chi) are indispensable for LTM maintenance in the Drosophila memory center, the mushroom bodies (MBs). On the other hand, Ap plays a crucial role in memory consolidation in a Chi-independent manner in pigment dispersing factor (Pdf)-containing large ventral–lateral clock neurons (l-LNvs) that modulate behavioral arousal and sleep. Since disrupted neurotransmission and electrical silencing in clock neurons impair memory consolidation, Ap is suggested to contribute to the stabilization of memory by ensuring the excitability of l-LNvs. Indeed, ex vivo imaging revealed that a reduced function of Ap, but not Chi, results in exaggerated Cl− responses to the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in l-LNvs, indicating that wild-type (WT) Ap maintains high l-LNv excitability by suppressing the GABA response. Consistently, enhancing the excitability of l-LNvs by knocking down GABAA receptors compensates for the impaired memory consolidation in ap null mutants. Overall, our results revealed unique dual functions of the developmental regulator Ap for LTM consolidation in clock neurons and LTM maintenance in MBs. A neurogenetic study using Drosophila reveals that the centrally expressed LIM-homeodomain transcription factor Apterous plays a crucial neuron-type-dependent role in two different memory processes - consolidation and maintenance of long-term memory.
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DaCrema D, Bhandari R, Karanja F, Yano R, Halme A. Ecdysone regulates the Drosophila imaginal disc epithelial barrier, determining the length of regeneration checkpoint delay. Development 2021; 148:dev.195057. [PMID: 33658221 DOI: 10.1242/dev.195057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 02/15/2021] [Indexed: 02/06/2023]
Abstract
Regeneration of Drosophila imaginal discs, larval precursors to adult tissues, activates a regeneration checkpoint that coordinates regenerative growth with developmental progression. This regeneration checkpoint results from the release of the relaxin-family peptide Dilp8 from regenerating imaginal tissues. Secreted Dilp8 protein is detected within the imaginal disc lumen, in which it is separated from its receptor target Lgr3, which is expressed in the brain and prothoracic gland, by the disc epithelial barrier. Here, we demonstrate that following damage the imaginal disc epithelial barrier limits Dilp8 signaling and the duration of regeneration checkpoint delay. We also find that the barrier becomes increasingly impermeable to the transepithelial diffusion of labeled dextran during the second half of the third instar. This change in barrier permeability is driven by the steroid hormone ecdysone and correlates with changes in localization of Coracle, a component of the septate junctions that is required for the late-larval impermeable epithelial barrier. Based on these observations, we propose that the imaginal disc epithelial barrier regulates the duration of the regenerative checkpoint, providing a mechanism by which tissue function can signal the completion of regeneration.
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Affiliation(s)
- Danielle DaCrema
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
| | - Rajan Bhandari
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
| | - Faith Karanja
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
| | - Ryunosuke Yano
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
| | - Adrian Halme
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
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4
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Maier D. Membrane-Anchored Hairless Protein Restrains Notch Signaling Activity. Genes (Basel) 2020; 11:genes11111315. [PMID: 33171957 PMCID: PMC7694644 DOI: 10.3390/genes11111315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/03/2020] [Accepted: 11/04/2020] [Indexed: 11/16/2022] Open
Abstract
The Notch signaling pathway governs cell-to-cell communication in higher eukaryotes. In Drosophila, after cleavage of the transmembrane receptor Notch, the intracellular domain of Notch (ICN) binds to the transducer Suppressor of Hairless (Su(H)) and shuttles into the nucleus to activate Notch target genes. Similarly, the Notch antagonist Hairless transfers Su(H) into the nucleus to repress Notch target genes. With the aim to prevent Su(H) nuclear translocation, Hairless was fused to a transmembrane domain to anchor the protein at membranes. Indeed, endogenous Su(H) co-localized with membrane-anchored Hairless, demonstrating their binding in the cytoplasm. Moreover, adult phenotypes uncovered a loss of Notch activity, in support of membrane-anchored Hairless sequestering Su(H) in the cytosol. A combined overexpression of membrane-anchored Hairless with Su(H) lead to tissue proliferation, which is in contrast to the observed apoptosis after ectopic co-overexpression of the wild-type genes, indicating a shift to a gain of Notch activity. A mixed response, general de-repression of Notch signaling output, plus inhibition at places of highest Notch activity, perhaps reflects Su(H)’s role as activator and repressor, supported by results obtained with the Hairless-binding deficient Su(H)LLL mutant, inducing activation only. Overall, the results strengthen the idea of Su(H) and Hairless complex formation within the cytosolic compartment.
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Affiliation(s)
- Dieter Maier
- Deptartment of General Genetics 190g, University of Hohenheim, Garbenstr. 30, 70599 Stuttgart, Germany
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5
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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: 20] [Impact Index Per Article: 5.0] [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
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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
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Brodskiy PA, Wu Q, Soundarrajan DK, Huizar FJ, Chen J, Liang P, Narciso C, Levis MK, Arredondo-Walsh N, Chen DZ, Zartman JJ. Decoding Calcium Signaling Dynamics during Drosophila Wing Disc Development. Biophys J 2019; 116:725-740. [PMID: 30704858 PMCID: PMC6382932 DOI: 10.1016/j.bpj.2019.01.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 12/04/2018] [Accepted: 01/04/2019] [Indexed: 01/07/2023] Open
Abstract
The robust specification of organ development depends on coordinated cell-cell communication. This process requires signal integration among multiple pathways, relying on second messengers such as calcium ions. Calcium signaling encodes a significant portion of the cellular state by regulating transcription factors, enzymes, and cytoskeletal proteins. However, the relationships between the inputs specifying cell and organ development, calcium signaling dynamics, and final organ morphology are poorly understood. Here, we have designed a quantitative image-analysis pipeline for decoding organ-level calcium signaling. With this pipeline, we extracted spatiotemporal features of calcium signaling dynamics during the development of the Drosophila larval wing disc, a genetic model for organogenesis. We identified specific classes of wing phenotypes that resulted from calcium signaling pathway perturbations, including defects in gross morphology, vein differentiation, and overall size. We found four qualitative classes of calcium signaling activity. These classes can be ordered based on agonist stimulation strength Gαq-mediated signaling. In vivo calcium signaling dynamics depend on both receptor tyrosine kinase/phospholipase C γ and G protein-coupled receptor/phospholipase C β activities. We found that spatially patterned calcium dynamics correlate with known differential growth rates between anterior and posterior compartments. Integrated calcium signaling activity decreases with increasing tissue size, and it responds to morphogenetic perturbations that impact organ growth. Together, these findings define how calcium signaling dynamics integrate upstream inputs to mediate multiple response outputs in developing epithelial organs.
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Affiliation(s)
- Pavel A Brodskiy
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Qinfeng Wu
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Dharsan K Soundarrajan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Francisco J Huizar
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Jianxu Chen
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Peixian Liang
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Cody Narciso
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Megan K Levis
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | | | - Danny Z Chen
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Jeremiah J Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana.
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Ramirez-Roman ME, Billini CE, Ghezzi A. Epigenetic Mechanisms of Alcohol Neuroadaptation: Insights from Drosophila. J Exp Neurosci 2018; 12:1179069518779809. [PMID: 29899666 PMCID: PMC5990879 DOI: 10.1177/1179069518779809] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 05/09/2018] [Indexed: 12/28/2022] Open
Abstract
Alcohol addiction is a serious condition perpetuated by enduring physiological and behavioral adaptations. An important component of these adaptations is the long-term rearrangement of neuronal gene expression in the brain of the addicted individual. Epigenetic histone modifications have recently surfaced as important modulators of the transcriptional adaptation to alcohol as these are thought to represent a form of transcriptional memory that is directly imprinted on the chromosome. Some histone modifications affect transcription by modulating the accessibility of the underlying DNA, whereas others have been proposed to serve as marks read by transcription factors as a "histone code" that helps to specify the expression level of a gene. Although the effects of some epigenetic modifications on the transcriptional activity of genes are well known, the mechanisms by which alcohol consumption produces this rearrangement and leads to lasting changes in behavior remain unresolved. Recent advances using the Drosophila model system have started to unravel the epigenetic modulators underlying functional alcohol neuroadaptations. In this review, we discuss the role of 3 different histone modification systems in Drosophila, which have a direct impact on key alcohol neuroadaptations associated with the addictive process. These systems involve the histone deacetylase Sirt1, the histone acetyltransferase CREB-binding protein (CBP), and a subset of the Drosophila JmjC-Domain histone demethylase family.
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Affiliation(s)
| | - Carlos E Billini
- Department of Biology, University of Puerto Rico–Rio Piedras, San Juan, PR, USA
| | - Alfredo Ghezzi
- Department of Biology, University of Puerto Rico–Rio Piedras, San Juan, PR, USA
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8
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Kairamkonda S, Nongthomba U. Beadex, a Drosophila LIM domain only protein, function in follicle cells is essential for egg development and fertility. Exp Cell Res 2018; 367:97-103. [PMID: 29580687 DOI: 10.1016/j.yexcr.2018.03.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 11/25/2022]
Abstract
LIM domain, constituted by two tandem C2H2 zinc finger motif, proteins regulate several biological processes. They are usually found associated with various functional domains like Homeodomain, kinase domain and other protein binding domains. LIM proteins that are devoid of other domains are called LIM only proteins (LMO). LMO proteins were first identified in humans and are implicated in development and oncogenesis. They regulate various cell specifications by regulating the activity of respective transcriptional complexes. The Drosophila LMO protein (dLMO), Beadex (Bx), regulates various developmental processes like wing margin development and bristle development. It also regulates Drosophila behavior in response to cocaine and ethanol. We have previously generated Bx null flies and shown its essential function in neurons for multiple aspects of female reproduction. However, it was not known whether Bx affects reproduction through its independent function in ovaries. In this paper we show that female flies null for Bx lay eggs with multiple defects. Further, through knock down studies we demonstrate that function of Bx in follicle cells is required for normal egg development. We also show that function of Bx is particularly required in border cells for Drosophila fertility.
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Affiliation(s)
- Subhash Kairamkonda
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Upendra Nongthomba
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India.
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9
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Reciprocal Negative Regulation Between Lmx1a and Lmo4 Is Required for Inner Ear Formation. J Neurosci 2018; 38:5429-5440. [PMID: 29769265 PMCID: PMC5990987 DOI: 10.1523/jneurosci.2484-17.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 02/07/2018] [Accepted: 02/11/2018] [Indexed: 02/07/2023] Open
Abstract
LIM-domain containing transcription factors (LIM-TFs) are conserved factors important for embryogenesis. The specificity of these factors in transcriptional regulation is conferred by the complexes that they form with other proteins such as LIM-domain-binding (Ldb) proteins and LIM-domain only (LMO) proteins. Unlike LIM-TFs, these proteins do not bind DNA directly. LMO proteins are negative regulators of LIM-TFs and function by competing with LIM-TFs for binding to Ldb's. Although the LIM-TF Lmx1a is expressed in the developing mouse hindbrain, which provides many of the extrinsic signals for inner ear formation, conditional knock-out embryos of both sexes show that the inner ear source of Lmx1a is the major contributor of ear patterning. In addition, we have found that the reciprocal interaction between Lmx1a and Lmo4 (a LMO protein within the inner ear) mediates the formation of both vestibular and auditory structures. Lmo4 negatively regulates Lmx1a to form the three sensory cristae, the anterior semicircular canal, and the shape of the utricle in the vestibule. Furthermore, this negative regulation blocks ectopic sensory formation in the cochlea. In contrast, Lmx1a negatively regulates Lmo4 in mediating epithelial resorption of the canal pouch, which gives rise to the anterior and posterior semicircular canals. We also found that Lmx1a is independently required for the formation of the endolymphatic duct and hair cells in the basal cochlear region. SIGNIFICANCE STATEMENT The mammalian inner ear is a structurally complex organ responsible for detecting sound and maintaining balance. Failure to form the intricate 3D structure of this organ properly during development most likely will result in sensory deficits on some level. Here, we provide genetic evidence that a transcription factor, Lmx1a, interacts with its negative regulator, Lmo4, to pattern various vestibular and auditory components of the mammalian inner ear. Identifying these key molecules that mediate formation of this important sensory organ will be helpful for designing strategies and therapeutics to alleviate hearing loss and balance disorders.
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Abstract
A hundred years after Lhx2 ortholog apterous was identified as a critical regulator of wing development in Drosophila, LIM-HD gene family members have proved to be versatile and powerful components of the molecular machinery that executes the blueprint of embryogenesis across vertebrate and invertebrate species. Here, we focus on the spatio-temporally varied functions of LIM-homeodomain transcription factor LHX2 in the developing mouse forebrain. Right from its earliest known role in telencephalic and eye field patterning, to the control of the neuron-glia cell fate switch, and the regulation of axon pathfinding and dendritic arborization in late embryonic stages, LHX2 has been identified as a fundamental, temporally dynamic, always necessary, and often sufficient factor in a range of critical developmental phenomena. While Lhx2 mutant phenotypes have been characterized in detail in multiple brain structures, only recently have we advanced in our understanding of the molecular mechanisms by which this factor acts. Common themes emerge from how this multifunctional molecule controls a range of developmental steps in distinct forebrain structures. Examining these shared features, and noting unique aspects of LHX2 function is likely to inform our understanding of how a single factor can bring about a diversity of effects and play central and critical roles across systems and stages. The parallels in LHX2 and APTEROUS functions, and the protein complexes they participate in, offer insights into evolutionary strategies that conserve tool kits and deploy them to play new, yet familiar roles in species separated by hundreds of millions of years.
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Affiliation(s)
- Shen-Ju Chou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Shubha Tole
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
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Al Khatib A, Siomava N, Iannini A, Posnien N, Casares F. Specific expression and function of the Six3 optix in Drosophila serially homologous organs. Biol Open 2017. [PMID: 28642242 PMCID: PMC5576073 DOI: 10.1242/bio.023606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Organ size and pattern results from the integration of two positional information systems. One global information system, encoded by the Hox genes, links organ type with position along the main body axis. Within specific organs, local information is conveyed by signaling molecules that regulate organ growth and pattern. The mesothoracic (T2) wing and the metathoracic (T3) haltere of Drosophila represent a paradigmatic example of this coordination. The Hox gene Ultrabithorax (Ubx), expressed in the developing T3, selects haltere identity by, among other processes, modulating the production and signaling efficiency of Dpp, a BMP2-like molecule that acts as a major regulator of size and pattern. However, the mechanisms of the Hox-signal integration in this well-studied system are incomplete. Here, we have investigated this issue by studying the expression and function of the Six3 transcription factor optix during Drosophila wing and haltere development. We find that in both organs, Dpp defines the expression domain of optix through repression, and that the specific position of this domain in wing and haltere seems to reflect the differential signaling profile among these organs. We show that optix expression in wing and haltere primordia is conserved beyond Drosophila in other higher diptera. In Drosophila, optix is necessary for the growth of wing and haltere. In the wing, optix is required for the growth of the most anterior/proximal region (the ‘marginal cell’) and for the correct formation of sensory structures along the proximal anterior wing margin; the halteres of optix mutants are also significantly reduced. In addition, in the haltere, optix is necessary for the suppression of sensory bristles. Summary: The position of the Six3 optix is regulated by the Dpp pathway during wing and haltere development, and controls the size of both serially homologous organs.
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Affiliation(s)
- Amer Al Khatib
- Department of Gene Regulation and Morphogenesis, Andalusian Centre for Developmental Biology (CABD), CSIC-Pablo de Olavide University-JA, 41013 Seville, Spain.,Department of Biology, University of Florence, I-50019, Florence, Italy
| | - Natalia Siomava
- Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Goettingen Center for Molecular Biosciences (GZMB), Department of Developmental Biology, University of Goettingen, 37077 Goettingen, Germany
| | - Antonella Iannini
- Department of Gene Regulation and Morphogenesis, Andalusian Centre for Developmental Biology (CABD), CSIC-Pablo de Olavide University-JA, 41013 Seville, Spain
| | - Nico Posnien
- Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Goettingen Center for Molecular Biosciences (GZMB), Department of Developmental Biology, University of Goettingen, 37077 Goettingen, Germany
| | - Fernando Casares
- Department of Gene Regulation and Morphogenesis, Andalusian Centre for Developmental Biology (CABD), CSIC-Pablo de Olavide University-JA, 41013 Seville, Spain
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12
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Chi and dLMO function antagonistically on Notch signaling through directly regulation of fng transcription. Sci Rep 2016; 6:18937. [PMID: 26738424 PMCID: PMC4704065 DOI: 10.1038/srep18937] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/01/2015] [Indexed: 11/08/2022] Open
Abstract
Gene apterous (ap), chip (chi) and beadex (bx) play important roles in the dorsal-ventral compartmentalization in Drosophila wing discs. Meanwhile, Notch signaling is essential to the same process. It has been reported that Ap and Chi function as a tetramer to regulate Notch signaling. At the same time, dLMO (the protein product of gene bx) regulates the activity of Ap by competing its binding with Chi. However, the detailed functions of Chi and dLMO on Notch signaling and the relevant mechanisms remain largely unknown. Here, we report the detailed functions of Chi and dLMO on Notch signaling. Different Chi protein levels in adjacent cells could activate Notch signaling mainly in the cells with higher level of Chi. dLMO could induce antagonistical phenotypes on Notch signaling compared to that induced by Chi. These processes depend on their direct regulation of fringe (fng) transcription.
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13
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Liu Y, Singh SR, Zeng X, Zhao J, Hou SX. The Nuclear Matrix Protein Megator Regulates Stem Cell Asymmetric Division through the Mitotic Checkpoint Complex in Drosophila Testes. PLoS Genet 2015; 11:e1005750. [PMID: 26714316 PMCID: PMC4703072 DOI: 10.1371/journal.pgen.1005750] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/27/2015] [Indexed: 11/29/2022] Open
Abstract
In adult Drosophila testis, asymmetric division of germline stem cells (GSCs) is specified by an oriented spindle and cortically localized adenomatous coli tumor suppressor homolog 2 (Apc2). However, the molecular mechanism underlying these events remains unclear. Here we identified Megator (Mtor), a nuclear matrix protein, which regulates GSC maintenance and asymmetric division through the spindle assembly checkpoint (SAC) complex. Loss of Mtor function results in Apc2 mis-localization, incorrect centrosome orientation, defective mitotic spindle formation, and abnormal chromosome segregation that lead to the eventual GSC loss. Expression of mitotic arrest-deficient-2 (Mad2) and monopolar spindle 1 (Mps1) of the SAC complex effectively rescued the GSC loss phenotype associated with loss of Mtor function. Collectively our results define a new role of the nuclear matrix-SAC axis in regulating stem cell maintenance and asymmetric division. Like many stem cells, the adult Drosophila male GSC often divides asymmetrically to produce one new stem cell and one gonialblast. The asymmetric division of GSC is specified by perpendicular orientation of the mitotic spindle to the hub-GSC interface and localization of Apc2. Here we show that Tpr/Mtor regulates GSC self-renewal and asymmetric division through the SAC complex. We found that Mtor cell-autonomously required in both GSCs and CySCs to regulate their self-renewal. Loss of Mtor function affects expression and localization of Apc2 and E-cadherin. We further found that Mtor is required for the correct centrosome orientation, mitotic spindle formation, and chromosome segregation. These defects are rescued by SAC complex components, Mps1 and Mad2. These data together suggest that Mtor regulates GSC asymmetric division and maintenance through the mitotic spindle checkpoint complex. We suggest that disruption of the Tpr-SAC pathway might lead to chromosome instability, chromosome lagging, and aneuploidy, stem cell division defects, and thereby tumor development.
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Affiliation(s)
- Ying Liu
- The Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland, United States of America
| | - Shree Ram Singh
- The Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland, United States of America
| | - Xiankun Zeng
- The Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland, United States of America
| | - Jiangsha Zhao
- The Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland, United States of America
| | - Steven X. Hou
- The Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland, United States of America
- * E-mail:
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Establishment of a Developmental Compartment Requires Interactions between Three Synergistic Cis-regulatory Modules. PLoS Genet 2015; 11:e1005376. [PMID: 26468882 PMCID: PMC4607503 DOI: 10.1371/journal.pgen.1005376] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 06/19/2015] [Indexed: 12/28/2022] Open
Abstract
The subdivision of cell populations in compartments is a key event during animal development. In Drosophila, the gene apterous (ap) divides the wing imaginal disc in dorsal vs ventral cell lineages and is required for wing formation. ap function as a dorsal selector gene has been extensively studied. However, the regulation of its expression during wing development is poorly understood. In this study, we analyzed ap transcriptional regulation at the endogenous locus and identified three cis-regulatory modules (CRMs) essential for wing development. Only when the three CRMs are combined, robust ap expression is obtained. In addition, we genetically and molecularly analyzed the trans-factors that regulate these CRMs. Our results propose a three-step mechanism for the cell lineage compartment expression of ap that includes initial activation, positive autoregulation and Trithorax-mediated maintenance through separable CRMs. The separation of cell populations into distinct functional units is essential for both vertebrate and invertebrate animal development. A classical paradigm for this phenomenon is the establishment of developmental compartments during Drosophila wing development. These compartments depend on the restricted expression of two selector genes, engrailed in the posterior compartment and apterous (ap) in the dorsal compartment. Yet, despite the central role these genes and their restricted expression patterns play in Drosophila development, we still do not understand how these patterns are established or maintained. Here, by dissecting the regulatory sequences required for ap expression, we solve this problem for this critical selector gene. We used a combination of experimental approaches to identify and functionally characterize the cis-regulatory modules (CRMs) that regulate ap expression during Drosophila wing development. For these analyses we implement a novel technique allowing us to study the function of these CRMs in vivo, at the native ap locus. We found three ap CRMs crucial for wing development: the Early (apE) and the D/V (apDV) enhancers and the ap PRE (apP). Only when all three regulatory elements are combined is a uniform and complete ap expression domain generated. In summary, our results indicate that ap is regulated in time and space by a three-step mechanism that generates a lineage compartment by integrating input from separate CRMs for the initiation, refinement and maintenance of its expression.
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Chou MH, Hsieh YC, Huang CW, Chen PH, Chan SP, Tsao YP, Lee HH, Wu JT, Chen SL. BCAS2 Regulates Delta-Notch Signaling Activity through Delta Pre-mRNA Splicing in Drosophila Wing Development. PLoS One 2015; 10:e0130706. [PMID: 26091239 PMCID: PMC4475048 DOI: 10.1371/journal.pone.0130706] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 05/23/2015] [Indexed: 11/19/2022] Open
Abstract
Previously, we showed that BCAS2 is essential for Drosophila viability and functions in pre-mRNA splicing. In this study, we provide strong evidence that BCAS2 regulates the activity of Delta-Notch signaling via Delta pre-mRNA splicing. Depletion of dBCAS2 reduces Delta mRNA expression and leads to accumulation of Delta pre-mRNA, resulting in diminished transcriptions of Delta-Notch signaling target genes, such as cut and E(spl)m8. Furthermore, ectopic expression of human BCAS2 (hBCAS2) and Drosophila BCAS2 (dBCAS2) in a dBCAS2-deprived fly can rescue dBCAS2 depletion-induced wing damage to the normal phenotypes. These rescued phenotypes are correlated with the restoration of Delta pre-mRNA splicing, which affects Delta-Notch signaling activity. Additionally, overexpression of Delta can rescue the wing deformation by deprivation of dBCAS2; and the depletion of dBCAS2 can restore the aberrant eye associated with Delta-overexpressing retinas; providing supporting evidence for the regulation of Delta-Notch signaling by dBCAS2. Taken together, dBCAS2 participates in Delta pre-mRNA splicing that affects the regulation of Delta-Notch signaling in Drosophila wing development.
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Affiliation(s)
- Meng-Hsuan Chou
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Yi-Chen Hsieh
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Chu-Wei Huang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Po-Han Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Shih-Peng Chan
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Yeou-Ping Tsao
- Department of Ophthalmology, Mackay Memorial Hospital, Taipei, 104, Taiwan
| | - Hsiu-Hsiang Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - June-Tai Wu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei, 100, Taiwan
- * E-mail: (SLC); (JTW)
| | - Show-Li Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
- * E-mail: (SLC); (JTW)
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Chip physically interacts with Notch and their stoichiometry is critical for Notch function in wing development and cell proliferation in Drosophila. Biochim Biophys Acta Gen Subj 2015; 1850:802-12. [DOI: 10.1016/j.bbagen.2014.12.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/15/2014] [Accepted: 12/27/2014] [Indexed: 12/17/2022]
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17
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Kairamkonda S, Nongthomba U. Beadex function in the motor neurons is essential for female reproduction in Drosophila melanogaster. PLoS One 2014; 9:e113003. [PMID: 25396431 PMCID: PMC4232528 DOI: 10.1371/journal.pone.0113003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/17/2014] [Indexed: 01/08/2023] Open
Abstract
Drosophila melanogaster has served as an excellent model system for understanding the neuronal circuits and molecular mechanisms regulating complex behaviors. The Drosophila female reproductive circuits, in particular, are well studied and can be used as a tool to understand the role of novel genes in neuronal function in general and female reproduction in particular. In the present study, the role of Beadex, a transcription co-activator, in Drosophila female reproduction was assessed by generation of mutant and knock down studies. Null allele of Beadex was generated by transposase induced excision of P-element present within an intron of Beadex gene. The mutant showed highly compromised reproductive abilities as evaluated by reduced fecundity and fertility, abnormal oviposition and more importantly, the failure of sperm release from storage organs. However, no defect was found in the overall ovariole development. Tissue specific, targeted knock down of Beadex indicated that its function in neurons is important for efficient female reproduction, since its neuronal knock down led to compromised female reproductive abilities, similar to Beadex null females. Further, different neuronal class specific knock down studies revealed that Beadex function is required in motor neurons for normal fecundity and fertility of females. Thus, the present study attributes a novel and essential role for Beadex in female reproduction through neurons.
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Affiliation(s)
- Subhash Kairamkonda
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Upendra Nongthomba
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, India
- * E-mail:
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18
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Huang YC, Lu YN, Wu JT, Chien CT, Pi H. The COP9 signalosome converts temporal hormone signaling to spatial restriction on neural competence. PLoS Genet 2014; 10:e1004760. [PMID: 25393278 PMCID: PMC4230841 DOI: 10.1371/journal.pgen.1004760] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/16/2014] [Indexed: 12/23/2022] Open
Abstract
During development, neural competence is conferred and maintained by integrating spatial and temporal regulations. The Drosophila sensory bristles that detect mechanical and chemical stimulations are arranged in stereotypical positions. The anterior wing margin (AWM) is arrayed with neuron-innervated sensory bristles, while posterior wing margin (PWM) bristles are non-innervated. We found that the COP9 signalosome (CSN) suppresses the neural competence of non-innervated bristles at the PWM. In CSN mutants, PWM bristles are transformed into neuron-innervated, which is attributed to sustained expression of the neural-determining factor Senseless (Sens). The CSN suppresses Sens through repression of the ecdysone signaling target gene broad (br) that encodes the BR-Z1 transcription factor to activate sens expression. Strikingly, CSN suppression of BR-Z1 is initiated at the prepupa-to-pupa transition, leading to Sens downregulation, and termination of the neural competence of PWM bristles. The role of ecdysone signaling to repress br after the prepupa-to-pupa transition is distinct from its conventional role in activation, and requires CSN deneddylating activity and multiple cullins, the major substrates of deneddylation. Several CSN subunits physically associate with ecdysone receptors to represses br at the transcriptional level. We propose a model in which nuclear hormone receptors cooperate with the deneddylation machinery to temporally shutdown downstream target gene expression, conferring a spatial restriction on neural competence at the PWM. A critical step in building a functional nervous system is to generate neurons at the appropriate locations. Neural competence is acquired at the precursor stage with the expression of specific transcription factors. One such critical factor is Senseless (Sens), as precursors lacking Sens fail to develop to neurons. Here we describe the critical role of protein complex COP9 signalosome (CSN) that regulates Sens expression by integrating temporal and spatial information. This was studied in developing Drosophila wing tissues, in which the anterior wing margin develops neuron-innervated bristles, while the posterior wing margin develops non-innervated bristles. The CSN complex is required for the anterior-posterior difference in spatial patterning of neuron formation, and posterior cells lacking CSN develop innervated bristles like anterior cells. CSN accomplishes this by transforming the temporal hormonal ecdysone signaling from activation to repression of downstream target BR-Z1. As BR-Z1 itself is a transcription activator, repression of BR-Z1 in turn leads to repression of Sens in posterior wing margin, eventually terminating the neural competence. Repression of BR-Z1 expression requires the interaction between the CSN complex and the ecdysone receptors. Our results suggest a novel CSN-mediated regulation that converts temporal hormone signaling to the patterning of neurons at the right place.
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Affiliation(s)
- Yi-Chun Huang
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
- Insitute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Nung Lu
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - June-Tai Wu
- Institute of Molecular Biology, National Taiwan University, Taipei, Taiwan
| | - Cheng-Ting Chien
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Insitute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail: (CTC); (HP)
| | - Haiwei Pi
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
- * E-mail: (CTC); (HP)
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19
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Ren J, Zhu H, Chi C, Mehrmohamadi M, Deng K, Wu X, Xu T. Beadex affects gastric emptying in Drosophila. Cell Res 2014; 24:636-9. [PMID: 24566770 PMCID: PMC4011345 DOI: 10.1038/cr.2014.24] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Jing Ren
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital, Fudan University, Shanghai 200433, China
- Current address: State Key Laboratory of Dairy Biotechnology, Dairy Research Institute, Bright Dairy & Food Co., Ltd. Bldg. 2, No.1518, West Jiangchang Road, Shanghai 200436, China
| | - Huanhu Zhu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital, Fudan University, Shanghai 200433, China
| | - Chongwu Chi
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital, Fudan University, Shanghai 200433, China
| | - Mahya Mehrmohamadi
- Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Kejing Deng
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital, Fudan University, Shanghai 200433, China
| | - Xiaohui Wu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital, Fudan University, Shanghai 200433, China
| | - Tian Xu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, School of Life Sciences, Children's Hospital, Fudan University, Shanghai 200433, China
- Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
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20
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Lakhina V, Subramanian L, Huilgol D, Shetty AS, Vaidya VA, Tole S. Seizure evoked regulation of LIM-HD genes and co-factors in the postnatal and adult hippocampus. F1000Res 2013; 2:205. [PMID: 25110573 PMCID: PMC4111125 DOI: 10.12688/f1000research.2-205.v1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/01/2013] [Indexed: 12/03/2022] Open
Abstract
The LIM-homeodomain (LIM-HD) family of transcription factors is well known for its functions during several developmental processes including cell fate specification, cell migration and axon guidance, and its members play fundamental roles in hippocampal development. The hippocampus is a structure that displays striking activity dependent plasticity. We examined whether LIM-HD genes and their co-factors are regulated during kainic acid induced seizure in the adult rat hippocampus as well as in early postnatal rats, when the hippocampal circuitry is not fully developed. We report a distinct and field-specific regulation of LIM-HD genes
Lhx1,Lhx2, and
Lhx9, LIM-only gene
Lmo4, and cofactor
Clim1a in the adult hippocampus after seizure induction. In contrast none of these genes displayed altered levels upon induction of seizure in postnatal animals. Our results provide evidence of temporal and spatial seizure mediated regulation of LIM-HD family members and suggest that LIM-HD gene function may be involved in activity dependent plasticity in the adult hippocampus
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Affiliation(s)
- Vanisha Lakhina
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India ; Current affiliation: Lewis Sigler Institute for Integrative Genomics, Princeton University, NJ, USA
| | - Lakshmi Subramanian
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India ; Current affiliation: Department of Neurology, University of California, San Francisco, CA, USA
| | - Dhananjay Huilgol
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India ; Current affiliation: Cold Spring Harbor Laboratory, NY, USA
| | - Ashwin S Shetty
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Vidita A Vaidya
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Shubha Tole
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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21
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LMO4 is an essential cofactor in the Snail2-mediated epithelial-to-mesenchymal transition of neuroblastoma and neural crest cells. J Neurosci 2013; 33:2773-83. [PMID: 23407937 DOI: 10.1523/jneurosci.4511-12.2013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Neuroblastoma is an embryonic tumor derived from cells of the neural crest. Taking advantage of a newly developed neural crest lineage tracer and based on the hypothesis that the molecular mechanisms that mediate neural crest delamination are also likely to be involved in the spread of neuroblastoma, we were able to identify genes that are active both in neural crest development and neuroblastoma tumor formation. A subsequent search of the neuroblastoma gene server for human orthologues of genes differentially expressed in the chick embryo neural crest screen retrieved the LIM domain only protein 4 (LMO4), which was expressed in both cell types analyzed. Functional experiments in these two model systems revealed that LMO4 activity is required for neuroblastoma cell invasion and neural crest delamination. Moreover, we identified LMO4 as an essential cofactor in Snail2-mediated cadherin repression and in the epithelial-to-mesenchymal transition of both neural crest and neuroblastoma cells. Together, our results suggest that the association of high levels of LMO4 with aggressive neuroblastomas is dependent on LMO4 regulation of cadherin expression and hence, tumor invasiveness.
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22
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Chen PH, Lee CI, Weng YT, Tarn WY, Tsao YP, Kuo PC, Hsu PH, Huang CW, Huang CS, Lee HH, Wu JT, Chen SL. BCAS2 is essential for Drosophila viability and functions in pre-mRNA splicing. RNA (NEW YORK, N.Y.) 2013; 19:208-218. [PMID: 23249746 PMCID: PMC3543084 DOI: 10.1261/rna.034835.112] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Accepted: 11/14/2012] [Indexed: 06/01/2023]
Abstract
Here, we show that dBCAS2 (CG4980, human Breast Carcinoma Amplified Sequence 2 ortholog) is essential for the viability of Drosophila melanogaster. We find that ubiquitous or tissue-specific depletion of dBCAS2 leads to larval lethality, wing deformities, impaired splicing, and apoptosis. More importantly, overexpression of hBCAS2 rescues these defects. Furthermore, the C-terminal coiled-coil domain of hBCAS2 binds directly to CDC5L and recruits hPrp19/PLRG1 to form a core complex for splicing in mammalian cells and can partially restore wing damage induced by knocking down dBCAS2 in flies. In summary, Drosophila and human BCAS2 share a similar function in RNA splicing, which affects cell viability.
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Affiliation(s)
- Po-Han Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chia-I Lee
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Yu-Tzu Weng
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Yeou-Ping Tsao
- Department of Ophthalmology, Mackay Memorial Hospital, Taipei 104, Taiwan
| | - Ping-Chang Kuo
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Pang-Hung Hsu
- Department of Life Science, College of Life Sciences, National Taiwan Ocean University, Keelung 202, Taiwan
- Institute of Bioscience and Biotechnology, College of Life Sciences, National Taiwan Ocean University, Keelung 202, Taiwan
| | - Chu-Wei Huang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chiun-Sheng Huang
- Department of Surgery, College of Medicine, National Taiwan University and Hospital, Taipei 100, Taiwan
| | - Hsiu-Hsiang Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - June-Tai Wu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Show-Li Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
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23
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Chatterjee M, Li K, Chen L, Maisano X, Guo Q, Gan L, Li JYH. Gbx2 regulates thalamocortical axon guidance by modifying the LIM and Robo codes. Development 2012; 139:4633-43. [PMID: 23136391 PMCID: PMC3509725 DOI: 10.1242/dev.086991] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2012] [Indexed: 11/20/2022]
Abstract
Combinatorial expression of transcription factors forms transcriptional codes to confer neuronal identities and connectivity. However, how these intrinsic factors orchestrate the spatiotemporal expression of guidance molecules to dictate the responsiveness of axons to guidance cues is less understood. Thalamocortical axons (TCAs) represent the major input to the neocortex and modulate cognitive functions, consciousness and alertness. TCAs travel a long distance and make multiple target choices en route to the cortex. The homeodomain transcription factor Gbx2 is essential for TCA development, as loss of Gbx2 abolishes TCAs in mice. Using a novel TCA-specific reporter, we have discovered that thalamic axons are mostly misrouted to the ventral midbrain and dorsal midline of the diencephalon in Gbx2-deficient mice. Furthermore, conditionally deleting Gbx2 at different embryonic stages has revealed a sustained role of Gbx2 in regulating TCA navigation and targeting. Using explant culture and mosaic analyses, we demonstrate that Gbx2 controls the intrinsic responsiveness of TCAs to guidance cues. The guidance defects of Gbx2-deficient TCAs are associated with abnormal expression of guidance receptors Robo1 and Robo2. Finally, we demonstrate that Gbx2 controls Robo expression by regulating LIM-domain transcription factors through three different mechanisms: Gbx2 and Lhx2 compete for binding to the Lmo3 promoter and exert opposing effects on its transcription; repressing Lmo3 by Gbx2 is essential for Lhx2 activity to induce Robo2; and Gbx2 represses Lhx9 transcription, which in turn induces Robo1. Our findings illustrate the transcriptional control of differential expression of Robo1 and Robo2, which may play an important role in establishing the topography of TCAs.
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Affiliation(s)
- Mallika Chatterjee
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT 06030-6403, USA
| | - Kairong Li
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT 06030-6403, USA
| | - Li Chen
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT 06030-6403, USA
| | - Xu Maisano
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT 06030-6403, USA
| | - Qiuxia Guo
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT 06030-6403, USA
| | - Lin Gan
- Department of Ophthalmology, University of Rochester, School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - James Y. H. Li
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT 06030-6403, USA
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Fusion protein Isl1-Lhx3 specifies motor neuron fate by inducing motor neuron genes and concomitantly suppressing the interneuron programs. Proc Natl Acad Sci U S A 2012; 109:3383-8. [PMID: 22343290 DOI: 10.1073/pnas.1114515109] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Combinatorial transcription codes generate the myriad of cell types during development and thus likely provide crucial insights into directed differentiation of stem cells to a specific cell type. The LIM complex composed of Isl1 and Lhx3 directs the specification of spinal motor neurons (MNs) in embryos. Here, we report that Isl1-Lhx3, a LIM-complex mimicking fusion, induces a signature of MN transcriptome and concomitantly suppresses interneuron differentiation programs, thereby serving as a potent and specific inducer of MNs in stem cells. We show that an equimolar ratio of Isl1 and Lhx3 and the LIM domain of Lhx3 are crucial for generating MNs without up-regulating interneuron genes. These led us to design Isl1-Lhx3, which maintains the desirable 1:1 ratio of Isl1 and Lhx3 and the LIM domain of Lhx3. Isl1-Lhx3 drives MN differentiation with high specificity and efficiency in the spinal cord and embryonic stem cells, bypassing the need for sonic hedgehog (Shh). RNA-seq analysis revealed that Isl1-Lhx3 induces the expression of a battery of MN genes that control various functional aspects of MNs, while suppressing key interneuron genes. Our studies uncover a highly efficient method for directed MN generation and MN gene networks. Our results also demonstrate a general strategy of using embryonic transcription complexes for producing specific cell types from stem cells.
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25
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Wg signaling via Zw3 and mad restricts self-renewal of sensory organ precursor cells in Drosophila. Genetics 2011; 189:809-24. [PMID: 21868604 DOI: 10.1534/genetics.111.133801] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
It is well known that the Dpp signal transducer Mad is activated by phosphorylation at its carboxy-terminus. The role of phosphorylation on other regions of Mad is not as well understood. Here we report that the phosphorylation of Mad in the linker region by the Wg antagonist Zw3 (homolog of vertebrate Gsk3-β) regulates the development of sensory organs in the anterior-dorsal quadrant of the wing. Proneural expression of Mad-RNA interference (RNAi) or a Mad transgene with its Zw3/Gsk3-β phosphorylation sites mutated (MGM) generated wings with ectopic sensilla and chemosensory bristle duplications. Studies with pMad-Gsk (an antibody specific to Zw3/Gsk3-β-phosphorylated Mad) in larval wing disks revealed that this phosphorylation event is Wg dependent (via an unconventional mechanism), is restricted to anterior-dorsal sensory organ precursors (SOP) expressing Senseless (Sens), and is always co-expressed with the mitotic marker phospho-histone3. Quantitative analysis in both Mad-RNAi and MGM larval wing disks revealed a significant increase in the number of Sens SOP. We conclude that the phosphorylation of Mad by Zw3 functions to prevent the self-renewal of Sens SOP, perhaps facilitating their differentiation via asymmetric division. The conservation of Zw3/Gsk3-β phosphorylation sites in vertebrate homologs of Mad (Smads) suggests that this pathway, the first transforming growth factor β-independent role for any Smad protein, may be widely utilized for regulating mitosis during development.
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26
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Asprer JST, Lee B, Wu CS, Vadakkan T, Dickinson ME, Lu HC, Lee SK. LMO4 functions as a co-activator of neurogenin 2 in the developing cortex. Development 2011; 138:2823-32. [PMID: 21652654 DOI: 10.1242/dev.061879] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The proneural protein neurogenin 2 (NGN2) is a key transcription factor in regulating both neurogenesis and neuronal radial migration in the embryonic cerebral cortex. However, the co-factors that support the action of NGN2 in the cortex remain unclear. Here, we show that the LIM-only protein LMO4 functions as a novel co-factor of NGN2 in the developing cortex. LMO4 and its binding partner nuclear LIM interactor (NLI/LDB1/CLIM2) interact with NGN2 simultaneously, forming a multi-protein transcription complex. This complex is recruited to the E-box containing enhancers of NGN2-target genes, which regulate various aspects of cortical development, and activates NGN2-mediated transcription. Correspondingly, analysis of Lmo4-null embryos shows that the loss of LMO4 leads to impairments of neuronal differentiation in the cortex. In addition, expression of LMO4 facilitates NGN2-mediated radial migration of cortical neurons in the embryonic cortex. Our results indicate that LMO4 promotes the acquisition of cortical neuronal identities by forming a complex with NGN2 and subsequently activating NGN2-dependent gene expression.
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Affiliation(s)
- Joanna S T Asprer
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
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Lasek AW, Lim J, Kliethermes CL, Berger KH, Joslyn G, Brush G, Xue L, Robertson M, Moore MS, Vranizan K, Morris SW, Schuckit MA, White RL, Heberlein U. An evolutionary conserved role for anaplastic lymphoma kinase in behavioral responses to ethanol. PLoS One 2011; 6:e22636. [PMID: 21799923 PMCID: PMC3142173 DOI: 10.1371/journal.pone.0022636] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 06/30/2011] [Indexed: 02/01/2023] Open
Abstract
Anaplastic lymphoma kinase (Alk) is a gene expressed in the nervous system that encodes a receptor tyrosine kinase commonly known for its oncogenic function in various human cancers. We have determined that Alk is associated with altered behavioral responses to ethanol in the fruit fly Drosophila melanogaster, in mice, and in humans. Mutant flies containing transposon insertions in dAlk demonstrate increased resistance to the sedating effect of ethanol. Database analyses revealed that Alk expression levels in the brains of recombinant inbred mice are negatively correlated with ethanol-induced ataxia and ethanol consumption. We therefore tested Alk gene knockout mice and found that they sedate longer in response to high doses of ethanol and consume more ethanol than wild-type mice. Finally, sequencing of human ALK led to the discovery of four polymorphisms associated with a low level of response to ethanol, an intermediate phenotype that is predictive of future alcohol use disorders (AUDs). These results suggest that Alk plays an evolutionary conserved role in ethanol-related behaviors. Moreover, ALK may be a novel candidate gene conferring risk for AUDs as well as a potential target for pharmacological intervention.
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Affiliation(s)
- Amy W. Lasek
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
- * E-mail: (UH); (AL)
| | - Jana Lim
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Christopher L. Kliethermes
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Karen H. Berger
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Geoff Joslyn
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Gerry Brush
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Liquan Xue
- Departments of Pathology and Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Margaret Robertson
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Monica S. Moore
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Karen Vranizan
- Functional Genomics Laboratory, University of California, Berkeley, California, United States of America
| | - Stephan W. Morris
- Departments of Pathology and Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Marc A. Schuckit
- Department of Psychiatry, University of California San Diego, La Jolla, California, United States of America
| | - Raymond L. White
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Ulrike Heberlein
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
- Department of Anatomy and Program in Neuroscience, University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (UH); (AL)
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Bronstein R, Segal D. Modularity of CHIP/LDB transcription complexes regulates cell differentiation. Fly (Austin) 2011; 5:200-5. [PMID: 21406967 DOI: 10.4161/fly.5.3.14854] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Transcription is the first step through which the cell operates, via its repertoire of transcription complexes, to direct cellular functions and cellular identity by generating the cell-specific transcriptome. The modularity of the composition of constituents of these complexes allows the cell to delicately regulate its transcriptome. In a recent study we have examined the effects of reducing the levels of specific transcription co-factors on the function of two competing transcription complexes, namely CHIP-AP and CHIP-PNR which regulate development of cells in the thorax of Drosophila. We found that changing the availability of these co-factors can shift the balance between these complexes leading to transition from utilization of CHIP-AP to CHIP-PNR. This is reflected in change in the expression profile of target genes, altering developmental cell fates. We propose that such a mechanism may operate in normal fly development. Transcription complexes analogous to CHIP-AP and CHIP-PNR exist in mammals and we discuss how such a shift in the balance between them may operate in normal mammalian development.
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Affiliation(s)
- Revital Bronstein
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
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Mouchel-Vielh E, Rougeot J, Decoville M, Peronnet F. The MAP kinase ERK and its scaffold protein MP1 interact with the chromatin regulator Corto during Drosophila wing tissue development. BMC DEVELOPMENTAL BIOLOGY 2011; 11:17. [PMID: 21401930 PMCID: PMC3062617 DOI: 10.1186/1471-213x-11-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 03/14/2011] [Indexed: 11/12/2022]
Abstract
Background Mitogen-activated protein kinase (MAPK) cascades (p38, JNK, ERK pathways) are involved in cell fate acquisition during development. These kinase modules are associated with scaffold proteins that control their activity. In Drosophila, dMP1, that encodes an ERK scaffold protein, regulates ERK signaling during wing development and contributes to intervein and vein cell differentiation. Functional relationships during wing development between a chromatin regulator, the Enhancer of Trithorax and Polycomb Corto, ERK and its scaffold protein dMP1, are examined here. Results Genetic interactions show that corto and dMP1 act together to antagonize rolled (which encodes ERK) in the future intervein cells, thus promoting intervein fate. Although Corto, ERK and dMP1 are present in both cytoplasmic and nucleus compartments, they interact exclusively in nucleus extracts. Furthermore, Corto, ERK and dMP1 co-localize on several sites on polytene chromosomes, suggesting that they regulate gene expression directly on chromatin. Finally, Corto is phosphorylated. Interestingly, its phosphorylation pattern differs between cytoplasm and nucleus and changes upon ERK activation. Conclusions Our data therefore suggest that the Enhancer of Trithorax and Polycomb Corto could participate in regulating vein and intervein genes during wing tissue development in response to ERK signaling.
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Affiliation(s)
- Emmanuèle Mouchel-Vielh
- Université Pierre et Marie Curie-Paris 6; Centre National de la Recherche Scientifique; UMR7622, Laboratoire de Biologie du Développement, Equipe Chromatine et Développement, 75005 Paris, France.
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Teufel A, Maass T, Strand S, Kanzler S, Galante T, Becker K, Strand D, Biesterfeld S, Westphal H, Galle PR. Liver-specific Ldb1 deletion results in enhanced liver cancer development. J Hepatol 2010; 53:1078-84. [PMID: 20828852 PMCID: PMC5903435 DOI: 10.1016/j.jhep.2010.05.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 05/23/2010] [Accepted: 05/26/2010] [Indexed: 01/15/2023]
Abstract
BACKGROUND & AIMS LIM-domain-binding (Ldb) proteins have been demonstrated to be essential not only to key embryonic developmental processes but also to carcinogenesis. We have previously demonstrated Ldb1 to be of high biological and developmental relevance, as a targeted deletion of the Ldb1 gene in mice results in an embryonic lethal and pleiotropic phenotype. METHODS We have now established a liver-specific Ldb1 knock out to investigate the role of Ldb1 in carcinogenesis, in particular in hepatocellular carcinoma (HCC) development, in vivo. RESULTS These mice demonstrated a significantly enhanced growth of liver cancer by means of tumor size and number, advocating for an essential role of Ldb1 in HCC development. In addition, proliferation and resistance against apoptosis were increased. In order to identify the functional disturbances due to a lack of Ldb1, we performed a 15k mouse gene microarray expression analysis. We found the Myc oncogene to be regulated in the microarray analysis and were able to further confirm this regulation by demonstrating an over-expression of its downstream target Cyclin D1. Furthermore, we were able to demonstrate a down-regulation of the tumor suppressor p21. Finally, the liver stem cell marker EpCAM was also identified to be over expressed in Ldb1(-/-) knock out mice. CONCLUSIONS We have established a significant role of Ldb1 in cancer development. Furthermore, we provided evidence for a myc/cyclin D1, p21, and EpCAM-dependent signalling to be key downstream regulators of this novel concept in HCC development.
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Affiliation(s)
- Andreas Teufel
- Department of Medicine I, Johannes Gutenberg University, Mainz, Germany.
| | - Thorsten Maass
- Department of Medicine I, Johannes Gutenberg University, Mainz, Germany
| | - Susanne Strand
- Department of Medicine I, Johannes Gutenberg University, Mainz, Germany
| | - Stephan Kanzler
- Department of Medicine I, Johannes Gutenberg University, Mainz, Germany
| | - Tiziana Galante
- Department of Medicine I, Johannes Gutenberg University, Mainz, Germany
| | - Kevin Becker
- Gene Expression Unit, National Institute On Aging, National Institutes of Health, Bethesda, MD, USA
| | - Dennis Strand
- Department of Medicine I, Johannes Gutenberg University, Mainz, Germany
| | | | - Heiner Westphal
- Laboratory of Mammalian Genes and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Peter R. Galle
- Department of Medicine I, Johannes Gutenberg University, Mainz, Germany
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Bronstein R, Levkovitz L, Yosef N, Yanku M, Ruppin E, Sharan R, Westphal H, Oliver B, Segal D. Transcriptional regulation by CHIP/LDB complexes. PLoS Genet 2010; 6:e1001063. [PMID: 20730086 PMCID: PMC2921152 DOI: 10.1371/journal.pgen.1001063] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 07/12/2010] [Indexed: 01/18/2023] Open
Abstract
It is increasingly clear that transcription factors play versatile roles in turning genes "on" or "off" depending on cellular context via the various transcription complexes they form. This poses a major challenge in unraveling combinatorial transcription complex codes. Here we use the powerful genetics of Drosophila combined with microarray and bioinformatics analyses to tackle this challenge. The nuclear adaptor CHIP/LDB is a major developmental regulator capable of forming tissue-specific transcription complexes with various types of transcription factors and cofactors, making it a valuable model to study the intricacies of gene regulation. To date only few CHIP/LDB complexes target genes have been identified, and possible tissue-dependent crosstalk between these complexes has not been rigorously explored. SSDP proteins protect CHIP/LDB complexes from proteasome dependent degradation and are rate-limiting cofactors for these complexes. By using mutations in SSDP, we identified 189 down-stream targets of CHIP/LDB and show that these genes are enriched for the binding sites of APTEROUS (AP) and PANNIER (PNR), two well studied transcription factors associated with CHIP/LDB complexes. We performed extensive genetic screens and identified target genes that genetically interact with components of CHIP/LDB complexes in directing the development of the wings (28 genes) and thoracic bristles (23 genes). Moreover, by in vivo RNAi silencing we uncovered novel roles for two of the target genes, xbp1 and Gs-alpha, in early development of these structures. Taken together, our results suggest that loss of SSDP disrupts the normal balance between the CHIP-AP and the CHIP-PNR transcription complexes, resulting in down-regulation of CHIP-AP target genes and the concomitant up-regulation of CHIP-PNR target genes. Understanding the combinatorial nature of transcription complexes as presented here is crucial to the study of transcription regulation of gene batteries required for development.
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Affiliation(s)
- Revital Bronstein
- Department of Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Liron Levkovitz
- Department of Physiology and Pharmacology, Tel Aviv University, Tel Aviv, Israel
- Balvatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel
| | - Nir Yosef
- Balvatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel
| | - Michaela Yanku
- Department of Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Eytan Ruppin
- Department of Physiology and Pharmacology, Tel Aviv University, Tel Aviv, Israel
- Balvatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel
| | - Roded Sharan
- Balvatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel
| | - Heiner Westphal
- Section on Mammalian Molecular Genetics, Program in Genomics of Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Brian Oliver
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Daniel Segal
- Department of Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
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32
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Quijano JC, Stinchfield MJ, Zerlanko B, Gibbens YY, Takaesu NT, Hyman-Walsh C, Wotton D, Newfeld SJ. The Sno oncogene antagonizes Wingless signaling during wing development in Drosophila. PLoS One 2010; 5:e11619. [PMID: 20661280 PMCID: PMC2905394 DOI: 10.1371/journal.pone.0011619] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Accepted: 06/15/2010] [Indexed: 11/18/2022] Open
Abstract
The Sno oncogene (Snoo or dSno in Drosophila) is a highly conserved protein and a well-established antagonist of Transforming Growth Factor-β signaling in overexpression assays. However, analyses of Sno mutants in flies and mice have proven enigmatic in revealing developmental roles for Sno proteins. Thus, to identify developmental roles for dSno we first reconciled conflicting data on the lethality of dSno mutations. Then we conducted analyses of wing development in dSno loss of function genotypes. These studies revealed ectopic margin bristles and ectopic campaniform sensilla in the anterior compartment of the wing blade suggesting that dSno functions to antagonize Wingless (Wg) signaling. A subsequent series of gain of function analyses yielded the opposite phenotype (loss of bristles and sensilla) and further suggested that dSno antagonizes Wg signal transduction in target cells. To date Sno family proteins have not been reported to influence the Wg pathway during development in any species. Overall our data suggest that dSno functions as a tissue-specific component of the Wg signaling pathway with modest antagonistic activity under normal conditions but capable of blocking significant levels of extraneous Wg, a role that may be conserved in vertebrates.
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Affiliation(s)
- Janine C. Quijano
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Michael J. Stinchfield
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Brad Zerlanko
- Department of Biochemistry and Molecular Genetics, and Center for Cell Signaling, University of Virginia, Charlottesville, Virginia, United States of America
| | - Ying Y. Gibbens
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Norma T. Takaesu
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Cathy Hyman-Walsh
- Department of Biochemistry and Molecular Genetics, and Center for Cell Signaling, University of Virginia, Charlottesville, Virginia, United States of America
| | - David Wotton
- Department of Biochemistry and Molecular Genetics, and Center for Cell Signaling, University of Virginia, Charlottesville, Virginia, United States of America
| | - Stuart J. Newfeld
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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33
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Tortoriello G, de Celis JF, Furia M. Linking pseudouridine synthases to growth, development and cell competition. FEBS J 2010; 277:3249-63. [DOI: 10.1111/j.1742-4658.2010.07731.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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34
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Regulation of LIM-domain-binding 1 protein expression by ubiquitination of Lys134. Biochem J 2010; 429:127-36. [PMID: 20423330 DOI: 10.1042/bj20091461] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
LDB1 (LIM-domain-binding 1) is a cofactor that participates in formation of transcriptional regulatory complexes involving transcription factors containing LIM domains as well as other factors. The amount of LDB1 protein in cells has previously been shown to be modulated by RNF12 (RING finger protein 12). RNF12 is an E3 ubiquitin ligase that can target LDB1 for poly-ubiquitination and degradation via the proteasome. We find that in HEK (human embryonic kidney)-293 cells expression of RNF12 leads to mono-ubiquitination of LDB1 and increased levels of LDB1 protein. Mutagenesis studies identified Lys134 of LDB1 as the residue that is mono-ubiquitinated by RNF12. Mutation of Lys134 of LDB1 to arginine blocks the formation of mono-ubiquitinated LDB1 and surprisingly also increases LDB1 protein expression in HEK-293 cells. This leads to a model in which Lys134 of LDB1 can be either mono-ubiquitinated, leading to stabilization, or poly-ubiquitinated, leading to degradation by the proteasome pathway. We also find that ubiquitin-LDB1 fusion proteins are stabilized in HEK-293 cells, offering further evidence that mono-ubiquitination stabilizes LDB1 in these cells. Expression in Xenopus laevis embryos of an LDB1 protein in which Lys134 is replaced with arginine leads to enhanced expression of the mutant protein as compared with the wild-type protein. These findings provide evidence that modification of Lys134 can play a major role in regulating LDB1 expression.
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35
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Bap170, a subunit of the Drosophila PBAP chromatin remodeling complex, negatively regulates the EGFR signaling. Genetics 2010; 186:167-81. [PMID: 20551433 DOI: 10.1534/genetics.110.118695] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BAP and PBAP constitute the two different forms of the Drosophila melanogaster Brahma chromatin remodelers. A common multisubunit core, containing the Brahma ATPase, can associate either with Osa to form the BAP complex or with Bap170, Bap180, and Sayp to constitute the PBAP complex. Although required for many biological processes, recent genetic analyses revealed that one role of the BAP complex during Drosophila wing development is the proper regulation of EGFR target genes. Here, we show that Bap170, a distinctive subunit of the PBAP complex, participates instead in the negative regulation of EGFR signaling. In adults, loss of Bap170 generates phenotypes similar to the defects induced by hyperactivation of the EGFR pathway, such as overrecruitment of cone and photoreceptor cells and formation extra veins. In genetic interactions, bap170 mutations suppress the loss of veins and photoreceptors caused by mutations affecting the activity of the EGFR pathway. Our results suggest a dual requirement of the PBAP complex: for transcriptional repression of rhomboid and for efficient expression of argos. Interestingly, genetic evidence also indicates that Bap170-mediated repression of rho is inhibited by EGFR signaling, suggesting a scenario of mutual antagonism between EGFR signaling and PBAP function.
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36
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Howard PW, Ransom DG, Maurer RA. Transcription intermediary factor 1gamma decreases protein expression of the transcriptional cofactor, LIM-domain-binding 1. Biochem Biophys Res Commun 2010; 396:674-8. [PMID: 20447379 DOI: 10.1016/j.bbrc.2010.04.160] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 04/28/2010] [Indexed: 10/19/2022]
Abstract
LIM-domain-binding 1 (LDB1) is a cofactor that participates in formation of regulatory complexes involving transcription factors containing LIM domains as well as other factors. We have examined the ability of transcriptional intermediary factor 1gamma (TIF1gamma) to decrease LDB1 expression. An expression vector for TIF1gamma was found to decrease expression of LDB1. A mutation which disrupts the ubiquitin ligase activity of TIF1gamma was found to block the ability of TIF1gamma to decrease LDB1 expression. Proteasome inhibitors were also able to block TIF1gamma effects on LDB1. Immunoprecipitation studies provided evidence that LDB1 interacts with TIF1gamma in intact cells. Knockdown of TIF1gamma in zebrafish embryos led to increased expression of LDB1 providing evidence for a physiological role of TIF1gamma in regulating LDB1 expression. Reporter gene assays demonstrated that TIF1gamma can alter the activity of LIM-homeodomain transcription factor-responsive promoters. These studies are consistent with a model in which TIF1gamma acts to ubiquitinate LDB1 leading to degradation of LDB1 and changes in transcription of LDB1-dependent promoters.
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Affiliation(s)
- Paul W Howard
- Department of Cell and Developmental Biology, Oregon Health and Science University, Portland, OR 97239, USA
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37
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Smibert P, Lai EC. A view from Drosophila: multiple biological functions for individual microRNAs. Semin Cell Dev Biol 2010; 21:745-53. [PMID: 20211749 DOI: 10.1016/j.semcdb.2010.03.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 03/01/2010] [Indexed: 12/19/2022]
Abstract
microRNAs (miRNAs) comprise an extensive class of post-transcriptional regulatory molecules in higher eukaryotes. Intensive research in Drosophila has revealed that miRNAs control myriad developmental and physiological processes. Interestingly, several of the best-studied miRNAs impact multiple biological processes, often by regulating distinct key target genes in each setting. Here we discuss the roles of some of these pleiotropic miRNAs, and their implications for studying and interpreting the roles of miRNAs in gene regulatory networks.
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Affiliation(s)
- Peter Smibert
- Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Ave, Box 252, New York, NY 10065, USA
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38
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Roignant JY, Legent K, Janody F, Treisman JE. The transcriptional co-factor Chip acts with LIM-homeodomain proteins to set the boundary of the eye field in Drosophila. Development 2010; 137:273-81. [PMID: 20040493 DOI: 10.1242/dev.041244] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Development involves the establishment of boundaries between fields specified to differentiate into distinct tissues. The Drosophila larval eye-antennal imaginal disc must be subdivided into regions that differentiate into the adult eye, antenna and head cuticle. We have found that the transcriptional co-factor Chip is required for cells at the ventral eye-antennal disc border to take on a head cuticle fate; clones of Chip mutant cells in this region instead form outgrowths that differentiate into ectopic eye tissue. Chip acts independently of the transcription factor Homothorax, which was previously shown to promote head cuticle development in the same region. Chip and its vertebrate CLIM homologues have been shown to form complexes with LIM-homeodomain transcription factors, and the domain of Chip that mediates these interactions is required for its ability to suppress the eye fate. We show that two LIM-homeodomain proteins, Arrowhead and Lim1, are expressed in the region of the eye-antennal disc affected in Chip mutants, and that both require Chip for their ability to suppress photoreceptor differentiation when misexpressed in the eye field. Loss-of-function studies support the model that Arrowhead and Lim1 act redundantly, using Chip as a co-factor, to prevent retinal differentiation in regions of the eye disc destined to become ventral head tissue.
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Affiliation(s)
- Jean-Yves Roignant
- Kimmel Center for Biology and Medicine of the Skirball Institute, NYU School of Medicine, Department of Cell Biology, 540 First Avenue, New York, NY 10016, USA
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miR-9a prevents apoptosis during wing development by repressing Drosophila LIM-only. Dev Biol 2009; 338:63-73. [PMID: 19944676 DOI: 10.1016/j.ydbio.2009.11.025] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 11/16/2009] [Accepted: 11/19/2009] [Indexed: 12/19/2022]
Abstract
Loss of Drosophila mir-9a induces a subtle increase in sensory bristles, but a substantial loss of wing tissue. Here, we establish that the latter phenotype is largely due to ectopic apoptosis in the dorsal wing primordium, and we could rescue wing development in the absence of this microRNA by dorsal-specific inhibition of apoptosis. Such apoptosis was a consequence of de-repressing Drosophila LIM-only (dLMO), which encodes a transcriptional regulator of wing and neural development. We observed cell-autonomous elevation of endogenous dLMO and a GFP-dLMO 3'UTR sensor in mir-9a mutant wing clones, and heterozygosity for dLMO rescued the apoptosis and wing defects of mir-9a mutants. We also provide evidence that dLMO, in addition to senseless, contributes to the bristle defects of the mir-9a mutant. Unexpectedly, the upregulation of dLMO, loss of Cut, and adult wing margin defects seen with mir-9a mutant clones were not recapitulated by clonal loss of the miRNA biogenesis factors Dicer-1 or Pasha, even though these mutant conditions similarly de-repressed miR-9a and dLMO sensor transgenes. Therefore, the failure to observe a phenotype upon conditional knockout of a miRNA processing factor does not reliably indicate the lack of critical roles of miRNAs in a given setting.
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40
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Song MR, Sun Y, Bryson A, Gill GN, Evans SM, Pfaff SL. Islet-to-LMO stoichiometries control the function of transcription complexes that specify motor neuron and V2a interneuron identity. Development 2009; 136:2923-32. [PMID: 19666821 DOI: 10.1242/dev.037986] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
LIM transcription factors bind to nuclear LIM interactor (Ldb/NLI/Clim) in specific ratios to form higher-order complexes that regulate gene expression. Here we examined how the dosage of LIM homeodomain proteins Isl1 and Isl2 and LIM-only protein Lmo4 influences the assembly and function of complexes involved in the generation of spinal motor neurons (MNs) and V2a interneurons (INs). Reducing the levels of Islet proteins using a graded series of mutations favored V2a IN differentiation at the expense of MN formation. Although LIM-only proteins (LMOs) are predicted to antagonize the function of Islet proteins, we found that the presence or absence of Lmo4 had little influence on MN or V2a IN specification. We did find, however, that the loss of MNs resulting from reduced Islet levels was rescued by eliminating Lmo4, unmasking a functional interaction between these proteins. Our findings demonstrate that MN and V2a IN fates are specified by distinct complexes that are sensitive to the relative stoichiometries of the constituent factors and we present a model to explain how LIM domain proteins modulate these complexes and, thereby, this binary-cell-fate decision.
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Affiliation(s)
- Mi-Ryoung Song
- Bioimaging Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
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Identification of the Drosophila Mes4 gene as a novel target of the transcription factor DREF. Exp Cell Res 2009; 315:1403-14. [DOI: 10.1016/j.yexcr.2008.12.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 12/18/2008] [Accepted: 12/18/2008] [Indexed: 12/16/2022]
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Joshi K, Lee S, Lee B, Lee JW, Lee SK. LMO4 controls the balance between excitatory and inhibitory spinal V2 interneurons. Neuron 2009; 62:641-54. [PMID: 19323994 DOI: 10.1016/j.neuron.2009.04.025] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 03/08/2009] [Accepted: 04/30/2009] [Indexed: 11/15/2022]
Abstract
Multiple excitatory and inhibitory interneurons form the motor circuit with motor neurons in the ventral spinal cord. Notch signaling initiates the diversification of immature V2-interneurons into excitatory V2a-interneurons and inhibitory V2b-interneurons. Here, we provide a transcriptional regulatory mechanism underlying their balanced production. LIM-only protein LMO4 controls this binary cell fate choice by regulating the activity of V2a- and V2b-specific LIM complexes inversely. In the spinal cord, LMO4 induces GABAergic V2b-interneurons in collaboration with SCL and inhibits Lhx3 from generating glutamatergic V2a-interneuons. In LMO4;SCL compound mutant embryos, V2a-interneurons increase markedly at the expense of V2b-interneurons. We further demonstrate that LMO4 nucleates the assembly of a novel LIM-complex containing SCL, Gata2, and NLI. This complex activates specific enhancers in V2b-genes consisting of binding sites for SCL and Gata2, thereby promoting V2b-interneuron fate. Thus, LMO4 plays essential roles in directing a balanced generation of inhibitory and excitatory neurons in the ventral spinal cord.
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Affiliation(s)
- Kaumudi Joshi
- Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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Joshi K, Lee S, Lee B, Lee JW, Lee SK. LMO4 controls the balance between excitatory and inhibitory spinal V2 interneurons. Neuron 2009; 61:839-51. [PMID: 19323994 DOI: 10.1016/j.neuron.2009.02.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 12/29/2008] [Accepted: 02/04/2009] [Indexed: 10/21/2022]
Abstract
Multiple excitatory and inhibitory interneurons form the motor circuit with motor neurons in the ventral spinal cord. Notch signaling initiates the diversification of immature V2-interneurons into excitatory V2a-interneurons and inhibitory V2b-interneurons. Here, we provide a transcriptional regulatory mechanism underlying their balanced production. LIM-only protein LMO4 controls this binary cell fate choice by regulating the activity of V2a- and V2b-specific LIM complexes inversely. In the spinal cord, LMO4 induces GABAergic V2b-interneurons in collaboration with SCL and inhibits Lhx3 from generating glutamatergic V2a-interneuons. In LMO4;SCL compound mutant embryos, V2a-interneurons increase markedly at the expense of V2b-interneurons. We further demonstrate that LMO4 nucleates the assembly of a novel LIM-complex containing SCL, Gata2, and NLI. This complex activates specific enhancers in V2b-genes consisting of binding sites for SCL and Gata2, thereby promoting V2b-interneuron fate. Thus, LMO4 plays essential roles in directing a balanced generation of inhibitory and excitatory neurons in the ventral spinal cord.
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Affiliation(s)
- Kaumudi Joshi
- Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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Azim E, Shnider SJ, Cederquist GY, Sohur US, Macklis JD. Lmo4 and Clim1 progressively delineate cortical projection neuron subtypes during development. ACTA ACUST UNITED AC 2009; 19 Suppl 1:i62-9. [PMID: 19366868 DOI: 10.1093/cercor/bhp030] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Molecular controls over the development of the exceptional neuronal subtype diversity of the cerebral cortex are now beginning to be identified. The initial subtype fate decision early in the life of a neuron, and the malleability of this fate when the balance of key postmitotic signals is modified, reveals not only that a neuron is deterministically set on a general developmental path at its birth, but also that this program must be precisely executed during postmitotic differentiation. Here, we show that callosal projection neurons (CPN) and subcerebral projection neurons (subcerebral PN) in layer V of the neocortex share aspects of molecular identity after their birth that are progressively resolved during differentiation. The LIM-homeodomain-related genes Lmo4 and Clim1 are initially expressed by both CPN and subcerebral PN in layer V, and only during mid to late differentiation does expression of Lmo4 and Clim1 become largely segregated into distinct neuronal subtypes. This progressive postmitotic resolution of molecular identity reveals similarities and possibly shared evolutionary origin between layer V CPN and subcerebral PN, and provides insight into how and when these neuronal subtypes achieve their distinct identities during cortical development.
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Affiliation(s)
- Eiman Azim
- MGH-HMS Center for Nervous System Repair, Departments of Neurosurgery and Neurology, Program in Neuroscience, Harvard Medical School, Boston, MA 02114, USA
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Biryukova I, Asmar J, Abdesselem H, Heitzler P. Drosophila mir-9a regulates wing development via fine-tuning expression of the LIM only factor, dLMO. Dev Biol 2009; 327:487-96. [PMID: 19162004 DOI: 10.1016/j.ydbio.2008.12.036] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 12/04/2008] [Accepted: 12/22/2008] [Indexed: 10/21/2022]
Abstract
MicroRNAs are short non-coding endogenous RNAs that are implicated in regulating various aspects of plants and animal development, however their functions in organogenesis are largely unknown. Here we report that mir-9a belonging to the mir-9 family, regulates Drosophila wing development through a functional target site in the 3' untranslated region of the Drosophila LIM only protein, dLMO. dLMO is a transcription cofactor, that directly inhibits the activity of Apterous, the LIM-HD factor required for the proper dorsal identity of the wings. Deletions of the 3' untranslated region, including the mir-9a site, generate gain-of-function dLMO mutants (Beadex) associated with high levels of dLMO mRNA and protein. Beadex mutants lack wing margins, a phenotype also observed in null mir-9a mutants. We found that mir-9a and dLMO are co-expressed in wing discs and interact genetically for controlling wing development. Lack of mir-9a results in overexpression of dLMO, while gain-of-function mir-9a mutant suppresses dLMO expression. These data indicate that a function of mir-9a is to ensure the appropriate stoichiometry of dLMO during Drosophila wing development. The mir-9a binding site is conserved in the human counterpart LMO2, the T-cell acute leukemia oncogene, suggesting that mir-9 might apply a similar strategy to maintain LMO2 expression under a detrimental threshold.
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Affiliation(s)
- Inna Biryukova
- Department of Cell and Developmental Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
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Abstract
LMO (LIM-only) and LIM-HD (LIM-homeodomain) proteins form a family of proteins that is required for myriad developmental processes and which can contribute to diseases such as T-cell leukaemia and breast cancer. The four LMO and 12 LIM-HD proteins in mammals are expressed in a combinatorial manner in many cell types, forming a transcriptional ‘LIM code’. The proteins all contain a pair of closely spaced LIM domains near their N-termini that mediate protein–protein interactions, including binding to the ∼30-residue LID (LIM interaction domain) of the essential co-factor protein Ldb1 (LIM domain-binding protein 1). In an attempt to understand the molecular mechanisms behind the LIM code, we have determined the molecular basis of binding of LMO and LIM-HD proteins for Ldb1LID through a series of structural, mutagenic and biophysical studies. These studies provide an explanation for why Ldb1 binds the LIM domains of the LMO/LIM-HD family, but not LIM domains from other proteins. The LMO/LIM-HD family exhibit a range of affinities for Ldb1, which influences the formation of specific functional complexes within cells. We have also identified an additional LIM interaction domain in one of the LIM-HD proteins, Isl1. Despite low sequence similarity to Ldb1LID, this domain binds another LIM-HD protein, Lhx3, in an identical manner to Ldb1LID. Through our and other studies, it is emerging that the multiple layers of competitive binding involving LMO and LIM-HD proteins and their partner proteins contribute significantly to cell fate specification and development.
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Abstract
Neurons acquire their molecular, neurochemical, and connectional features during development as a result of complex regulatory mechanisms. Here, we show that a ubiquitous, multifunctional protein cofactor, Chip, plays a critical role in a set of neurons in Drosophila that control the well described posteclosion behavior. Newly eclosed flies normally expand their wings and display tanning and hardening of their cuticle. Using multiple approaches to interfere with Chip function, we find that these processes do not occur without normal activity of this protein. Furthermore, we identified the nature of the deficit to be an absence of Bursicon in the hemolymph of newly eclosed flies, whereas the responsivity to Bursicon in these flies remains normal. Chip interacts with transcription factors of the LIM-HD (LIM-homeodomain) family, and we identified one member, dIslet, as a potential partner of Chip in this process. Our findings provide the first evidence of transcriptional mechanisms involved in the development of the neuronal circuit that regulates posteclosion behavior in Drosophila.
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A permissive role of Notch in maintaining the DV affinity boundary of the Drosophila wing. Dev Biol 2008; 322:190-8. [DOI: 10.1016/j.ydbio.2008.07.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 07/22/2008] [Accepted: 07/22/2008] [Indexed: 11/21/2022]
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Drosophila LIM-only is a positive regulator of transcription during thoracic bristle development. Genetics 2008; 179:1989-99. [PMID: 18689881 DOI: 10.1534/genetics.108.090076] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Drosophila LIM-only (LMO) protein DLMO functions as a negative regulator of transcription during development of the fly wing. Here we report a novel role of DLMO as a positive regulator of transcription during the development of thoracic sensory bristles. We isolated new dlmo mutants, which lack some thoracic dorsocentral (DC) bristles. This phenotype is typical of malfunction of a thoracic multiprotein transcription complex, composed of CHIP, PANNIER (PNR), ACHAETE (AC), and DAUGHTERLESS (DA). Genetic interactions reveal that dlmo synergizes with pnr and ac to promote the development of thoracic DC bristles. Moreover, loss-of-function of dlmo reduces the expression of a reporter target gene of this complex in vivo. Using the GAL4-UAS system we also show that dlmo is spatially expressed where this complex is known to be active. Glutathione-S-transferase (GST)-pulldown assays showed that DLMO can physically bind CHIP and PNR through either of the two LIM domains of DLMO, suggesting that DLMO might function as part of this transcription complex in vivo. We propose that DLMO exerts its positive effect on DC bristle development by serving as a bridging molecule between components of the thoracic transcription complex.
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Hu W, dePamphilis CW, Ma H. Phylogenetic analysis of the plant-specific zinc finger-homeobox and mini zinc finger gene families. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2008; 50:1031-45. [PMID: 18713354 DOI: 10.1111/j.1744-7909.2008.00681.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Zinc finger-homeodomain proteins (ZHD) are present in many plants; however, the evolutionary history of the ZHD gene family remains largely unknown. We show here that ZHD genes are plant-specific, nearly all intronless, and related to MINI ZINC FINGER (MIF) genes that possess only the zinc finger. Phylogenetic analyses of ZHD genes from representative land plants suggest that non-seed plant ZHD genes occupy basal positions and angiosperm homologs form seven distinct clades. Several clades contain genes from two or more major angiosperm groups, including eudicots, monocots, magnoliids, and other basal angiosperms, indicating that several duplications occurred before the diversification of flowering plants. In addition, specific lineages have experienced more recent duplications. Unlike the ZHD genes, MIFs are found only from seed plants, possibly derived from ZHDs by loss of the homeodomain before the divergence of seed plants. Moreover, the MIF genes have also undergone relatively recent gene duplications. Finally, genome duplication might have contributed substantially to the expansion of family size in angiosperms and caused a high level of functional redundancy/overlap in these genes.
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Affiliation(s)
- Wei Hu
- Department of Biology and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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