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Martinez-Salas E, Francisco-Velilla R. GEMIN5 and neurodevelopmental diseases: From functional insights to disease perception. Neural Regen Res 2026; 21:187-194. [PMID: 39819844 PMCID: PMC12094563 DOI: 10.4103/nrr.nrr-d-24-01010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2024] [Revised: 10/17/2024] [Accepted: 11/27/2024] [Indexed: 01/19/2025] Open
Abstract
GEMIN5 is a predominantly cytoplasmic multifunctional protein, known to be involved in recognizing snRNAs through its WD40 repeats domain placed at the N-terminus. A dimerization domain in the middle region acts as a hub for protein-protein interaction, while a non-canonical RNA-binding site is placed towards the C-terminus. The singular organization of structural domains present in GEMIN5 enables this protein to perform multiple functions through its ability to interact with distinct partners, both RNAs and proteins. This protein exerts a different role in translation regulation depending on its physiological state, such that while GEMIN5 down-regulates global RNA translation, the C-terminal half of the protein promotes translation of its mRNA. Additionally, GEMIN5 is responsible for the preferential partitioning of mRNAs into polysomes. Besides selective translation, GEMIN5 forms part of distinct ribonucleoprotein complexes, reflecting the dynamic organization of macromolecular complexes in response to internal and external signals. In accordance with its contribution to fundamental cellular processes, recent reports described clinical loss of function mutants suggesting that GEMIN5 deficiency is detrimental to cell growth and survival. Remarkably, patients carrying GEMIN5 biallelic variants suffer from neurodevelopmental delay, hypotonia, and cerebellar ataxia. Molecular analyses of individual variants, which are defective in protein dimerization, display decreased levels of ribosome association, reinforcing the involvement of the protein in translation regulation. Importantly, the number of clinical variants and the phenotypic spectrum associated with GEMIN5 disorders is increasing as the knowledge of the protein functions and the pathways linked to its activity augments. Here we discuss relevant advances concerning the functional and structural features of GEMIN5 and its separate domains in RNA-binding, protein interactome, and translation regulation, and how these data can help to understand the involvement of protein malfunction in clinical variants found in patients developing neurodevelopmental disorders.
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Cacciottolo R, Cauchi RJ. A critical genetic interaction between Gemin3/Ddx20 and translation initiation factor NAT1/eIF4G2 drives development. Dev Biol 2025; 521:37-51. [PMID: 39924071 DOI: 10.1016/j.ydbio.2025.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2024] [Revised: 01/28/2025] [Accepted: 02/06/2025] [Indexed: 02/11/2025]
Abstract
Gemin3 (Gem3) or DEAD-box RNA helicase 20 (Ddx20) has been mostly implicated in the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs) as part of the SMN-Gemins complex. Nonetheless, several studies have hinted at its participation in diverse snRNP-independent activities. Here, we utilised a narrow unbiased genetic screen to discover novel Gem3 interactors in Drosophila with the aim of gaining better insights on its function in vivo. Through this approach, we identified a novel genetic interaction between Gem3 and NAT1, which encodes the Drosophila orthologue of translational regulator eIF4G2. Despite lack of a physical association, loss of NAT1 function was found to downregulate Gem3 mRNA levels. Extensive convergence in transcriptome alterations downstream of Gem3 and NAT1 silencing further supports a functional relationship between these factors in addition to showing a requirement for both in actin cytoskeleton organisation and organism development, particularly neurodevelopment. In confirmation, flies with either Gem3 or NAT1 depletion exhibited brain growth defects and reduced muscle contraction. Severe delays in developmental progression were also observed in a newly generated Gem3 hypomorphic mutant. Our data linking Gemin3 to a key component of the translational machinery support an emerging role for Gemin3 in translation that is also critical during organism development.
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Affiliation(s)
- Rebecca Cacciottolo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta
| | - Ruben J Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta.
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Martinez‐Salas E, Abellan S, Francisco‐Velilla R. Understanding GEMIN5 Interactions: From Structural and Functional Insights to Selective Translation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2025; 16:e70008. [PMID: 40176294 PMCID: PMC11965781 DOI: 10.1002/wrna.70008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2024] [Revised: 02/14/2025] [Accepted: 02/15/2025] [Indexed: 04/04/2025]
Abstract
GEMIN5 is a predominantly cytoplasmic protein, initially identified as a member of the survival of motor neurons (SMN) complex. In addition, this abundant protein modulates diverse aspects of RNA-dependent processes, executing its functions through the formation of multi-component complexes. The modular organization of structural domains present in GEMIN5 enables this protein to perform various functions through its interaction with distinct partners. The protein is responsible for the recognition of small nuclear (sn)RNAs through its N-terminal region, and therefore for snRNP assembly. Beyond its role in spliceosome assembly, GEMIN5 regulates translation through the interaction with either RNAs or proteins. In the central region, a robust dimerization domain acts as a hub for protein-protein interaction, while a non-canonical RNA-binding site is located towards the C-terminus. Interestingly, GEMIN5 regulates the partitioning of mRNAs into polysomes, likely due to its RNA-binding capacity and its ability to bind native ribosomes. Understanding the functional and structural organization of the protein has brought an increasing interest in the last years with important implications in human disease. Patients carrying GEMIN5 biallelic variants suffer from neurodevelopmental delay, hypotonia, and cerebellar ataxia. This review discusses recent relevant works aimed at understanding the molecular mechanisms of GEMIN5 activity in gene expression, and also the challenges to discover new functions.
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Medyanik AD, Anisimova PE, Kustova AO, Tarabykin VS, Kondakova EV. Developmental and Epileptic Encephalopathy: Pathogenesis of Intellectual Disability Beyond Channelopathies. Biomolecules 2025; 15:133. [PMID: 39858526 PMCID: PMC11763800 DOI: 10.3390/biom15010133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2024] [Revised: 01/11/2025] [Accepted: 01/13/2025] [Indexed: 01/27/2025] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are a group of neuropediatric diseases associated with epileptic seizures, severe delay or regression of psychomotor development, and cognitive and behavioral deficits. What sets DEEs apart is their complex interplay of epilepsy and developmental delay, often driven by genetic factors. These two aspects influence one another but can develop independently, creating diagnostic and therapeutic challenges. Intellectual disability is severe and complicates potential treatment. Pathogenic variants are found in 30-50% of patients with DEE. Many genes mutated in DEEs encode ion channels, causing current conduction disruptions known as channelopathies. Although channelopathies indeed make up a significant proportion of DEE cases, many other mechanisms have been identified: impaired neurogenesis, metabolic disorders, disruption of dendrite and axon growth, maintenance and synapse formation abnormalities -synaptopathies. Here, we review recent publications on non-channelopathies in DEE with an emphasis on the mechanisms linking epileptiform activity with intellectual disability. We focus on three major mechanisms of intellectual disability in DEE and describe several recently identified genes involved in the pathogenesis of DEE.
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Affiliation(s)
- Alexandra D. Medyanik
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (A.D.M.); (P.E.A.); (A.O.K.); (E.V.K.)
| | - Polina E. Anisimova
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (A.D.M.); (P.E.A.); (A.O.K.); (E.V.K.)
| | - Angelina O. Kustova
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (A.D.M.); (P.E.A.); (A.O.K.); (E.V.K.)
| | - Victor S. Tarabykin
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (A.D.M.); (P.E.A.); (A.O.K.); (E.V.K.)
- Institute of Cell Biology and Neurobiology, Charité—Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Elena V. Kondakova
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (A.D.M.); (P.E.A.); (A.O.K.); (E.V.K.)
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Nelson CH, Pandey UB. Function and dysfunction of GEMIN5: understanding a novel neurodevelopmental disorder. Neural Regen Res 2024; 19:2377-2386. [PMID: 38526274 PMCID: PMC11090446 DOI: 10.4103/nrr.nrr-d-23-01614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/06/2023] [Accepted: 12/10/2023] [Indexed: 03/26/2024] Open
Abstract
The recent identification of a neurodevelopmental disorder with cerebellar atrophy and motor dysfunction (NEDCAM) has resulted in an increased interest in GEMIN5, a multifunction RNA-binding protein. As the largest member of the survival motor neuron complex, GEMIN5 plays a key role in the biogenesis of small nuclear ribonucleoproteins while also exhibiting translational regulatory functions as an independent protein. Although many questions remain regarding both the pathogenesis and pathophysiology of this new disorder, considerable progress has been made in the brief time since its discovery. In this review, we examine GEMIN5 within the context of NEDCAM, focusing on the structure, function, and expression of the protein specifically in regard to the disorder itself. Additionally, we explore the current animal models of NEDCAM, as well as potential molecular pathways for treatment and future directions of study. This review provides a comprehensive overview of recent advances in our understanding of this unique member of the survival motor neuron complex.
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Affiliation(s)
- Charles H. Nelson
- Department of Pediatrics, Division of Child Neurology, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Udai B. Pandey
- Department of Pediatrics, Division of Child Neurology, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
- Children’s Neuroscience Institute, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Matera AG, Steiner RE, Mills CA, McMichael BD, Herring LE, Garcia EL. Proteomic analysis of the SMN complex reveals conserved and etiologic connections to the proteostasis network. FRONTIERS IN RNA RESEARCH 2024; 2:1448194. [PMID: 39492846 PMCID: PMC11529804 DOI: 10.3389/frnar.2024.1448194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2024]
Abstract
Introduction Molecular chaperones and co-chaperones are highly conserved cellular components that perform a variety of duties related to the proper three-dimensional folding of the proteome. The web of factors that carries out this essential task is called the proteostasis network (PN). Ribonucleoproteins (RNPs) represent an underexplored area in terms of the connections they make with the PN. The Survival Motor Neuron (SMN) complex is an assembly chaperone and serves as a paradigm for studying how specific RNAs are identified and paired with their client substrate proteins to form RNPs. SMN is the eponymous component of a large complex, required for the biogenesis of uridine-rich small nuclear ribonucleoproteins (U-snRNPs), that localizes to distinct membraneless organelles in both the nucleus and cytoplasm of animal cells. SMN protein forms the oligomeric core of this complex, and missense mutations in the human SMN1 gene are known to cause Spinal Muscular Atrophy (SMA). The basic framework for understanding how snRNAs are assembled into U-snRNPs is known. However, the pathways and mechanisms used by cells to regulate their biogenesis are poorly understood. Methods Given the importance of these processes to normal development as well as neurodegenerative disease, we set out to identify and characterize novel SMN binding partners. We carried out affinity purification mass spectrometry (AP-MS) of Drosophila SMN complexes using fly lines exclusively expressing either wildtype or SMA-causing missense alleles. Results Bioinformatic analyses of the pulldown data, along with comparisons to proximity labeling studies carried out in human cells, revealed conserved connections to at least two other major chaperone systems including heat shock folding chaperones (HSPs) and histone/nucleosome assembly chaperones. Notably, we found that heat shock cognate protein Hsc70-4 and other HspA family members preferentially associated with SMA-causing alleles of SMN. Discussion Hsc70-4 is particularly interesting because its mRNA is aberrantly sequestered by a mutant form of TDP-43 in mouse and Drosophila ALS (Amyotrophic Lateral Sclerosis) disease models. Most important, a missense allele of Hsc70-4 (HspA8 in mammals) was recently identified as a bypass suppressor of the SMA phenotype in mice. Collectively, these findings suggest that chaperone-related dysfunction lies at the etiological root of both ALS and SMA.
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Affiliation(s)
- A. Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, United States
- Departments of Biology and Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- RNA Discovery and Lineberger Comprehensive Cancer Centers, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Rebecca E. Steiner
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, United States
| | - C. Allie Mills
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Benjamin D. McMichael
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, United States
| | - Laura E. Herring
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Eric L. Garcia
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, United States
- Department of Biology, University of Kentucky, Lexington, KY, United States
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Francisco-Velilla R, Abellan S, Embarc-Buh A, Martinez-Salas E. Oligomerization regulates the interaction of Gemin5 with members of the SMN complex and the translation machinery. Cell Death Discov 2024; 10:306. [PMID: 38942768 PMCID: PMC11213948 DOI: 10.1038/s41420-024-02057-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/29/2024] [Accepted: 06/04/2024] [Indexed: 06/30/2024] Open
Abstract
RNA-binding proteins are multifunctional molecules impacting on multiple steps of gene regulation. Gemin5 was initially identified as a member of the survival of motor neurons (SMN) complex. The protein is organized in structural and functional domains, including a WD40 repeats domain at the N-terminal region, a tetratricopeptide repeat (TPR) dimerization module at the central region, and a non-canonical RNA-binding site at the C-terminal end. The TPR module allows the recruitment of the endogenous Gemin5 protein in living cells and the assembly of a dimer in vitro. However, the biological relevance of Gemin5 oligomerization is not known. Here we interrogated the Gemin5 interactome focusing on oligomerization-dependent or independent regions. We show that the interactors associated with oligomerization-proficient domains were primarily annotated to ribosome, splicing, translation regulation, SMN complex, and RNA stability. The presence of distinct Gemin5 protein regions in polysomes highlighted differences in translation regulation based on their oligomerization capacity. Furthermore, the association with native ribosomes and negative regulation of translation was strictly dependent on both the WD40 repeats domain and the TPR dimerization moiety, while binding with the majority of the interacting proteins, including SMN, Gemin2, and Gemin4, was determined by the dimerization module. The loss of oligomerization did not perturb the predominant cytoplasmic localization of Gemin5, reinforcing the cytoplasmic functions of this essential protein. Our work highlights a distinctive role of the Gemin5 domains for its functions in the interaction with members of the SMN complex, ribosome association, and RBP interactome.
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Affiliation(s)
| | - Salvador Abellan
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049, Madrid, Spain
| | - Azman Embarc-Buh
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049, Madrid, Spain
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Matera AG, Steiner RE, Mills CA, Herring LE, Garcia EL. Chaperoning the chaperones: Proteomic analysis of the SMN complex reveals conserved and etiologic connections to the proteostasis network. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.15.594402. [PMID: 38903116 PMCID: PMC11188114 DOI: 10.1101/2024.05.15.594402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Molecular chaperones and co-chaperones are highly conserved cellular components that perform variety of duties related to the proper three-dimensional folding of the proteome. The web of factors that carries out this essential task is called the proteostasis network (PN). Ribonucleoproteins (RNPs) represent an underexplored area in terms of the connections they make with the PN. The Survival Motor Neuron (SMN) complex is an RNP assembly chaperone and serves as a paradigm for studying how specific small nuclear (sn)RNAs are identified and paired with their client substrate proteins. SMN protein is the eponymous component of a large complex required for the biogenesis of uridine-rich small nuclear ribonucleoproteins (U-snRNPs) and localizes to distinct membraneless organelles in both the nucleus and cytoplasm of animal cells. SMN forms the oligomeric core of this complex, and missense mutations in its YG box self-interaction domain are known to cause Spinal Muscular Atrophy (SMA). The basic framework for understanding how snRNAs are assembled into U-snRNPs is known, the pathways and mechanisms used by cells to regulate their biogenesis are poorly understood. Given the importance of these processes to normal development as well as neurodegenerative disease, we set out to identify and characterize novel SMN binding partners. Here, we carried out affinity purification mass spectrometry (AP-MS) of SMN using stable fly lines exclusively expressing either wildtype or SMA-causing missense alleles. Bioinformatic analyses of the pulldown data, along with comparisons to proximity labeling studies carried out in human cells, revealed conserved connections to at least two other major chaperone systems including heat shock folding chaperones (HSPs) and histone/nucleosome assembly chaperones. Notably, we found that heat shock cognate protein Hsc70-4 and other HspA family members preferentially interacted with SMA-causing alleles of SMN. Hsc70-4 is particularly interesting because its mRNA is aberrantly sequestered by a mutant form of TDP-43 in mouse and Drosophila ALS (Amyotrophic Lateral Sclerosis) disease models. Most important, a missense allele of Hsc70-4 (HspA8 in mammals) was recently identified as a bypass suppressor of the SMA phenotype in mice. Collectively, these findings suggest that chaperone-related dysfunction lies at the etiological root of both ALS and SMA.
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Affiliation(s)
- A. Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill NC, USA
- Departments of Biology and Genetics, University of North Carolina at Chapel Hill
- RNA Discovery and Lineberger Comprehensive Cancer Centers, University of North Carolina at Chapel Hill
| | - Rebecca E. Steiner
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill NC, USA
| | - C. Alison Mills
- Department of Pharmacology, University of North Carolina at Chapel Hill
| | - Laura E. Herring
- Department of Pharmacology, University of North Carolina at Chapel Hill
| | - Eric L. Garcia
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill NC, USA
- Department of Biology, University of Kentucky, Lexington KY, USA
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Francisco-Velilla R, Abellan S, Garcia-Martin JA, Oliveros JC, Martinez-Salas E. Alternative splicing events driven by altered levels of GEMIN5 undergo translation. RNA Biol 2024; 21:23-34. [PMID: 39194147 PMCID: PMC11364065 DOI: 10.1080/15476286.2024.2394755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/26/2024] [Accepted: 08/15/2024] [Indexed: 08/29/2024] Open
Abstract
GEMIN5 is a multifunctional protein involved in various aspects of RNA biology, including biogenesis of snRNPs and translation control. Reduced levels of GEMIN5 confer a differential translation to selective groups of mRNAs, and biallelic variants reducing protein stability or inducing structural conformational changes are associated with neurological disorders. Here, we show that upregulation of GEMIN5 can be detrimental as it modifies the steady state of mRNAs and enhances alternative splicing (AS) events of genes involved in a broad range of cellular processes. RNA-Seq identification of the mRNAs associated with polysomes in cells with high levels of GEMIN5 revealed that a significant fraction of the differential AS events undergo translation. The association of mRNAs with polysomes was dependent on the type of AS event, being more frequent in the case of exon skipping. However, there were no major differences in the percentage of genes showing open-reading frame disruption. Importantly, differential AS events in mRNAs engaged in polysomes, eventually rendering non-functional proteins, encode factors controlling cell growth. The broad range of mRNAs comprising AS events engaged in polysomes upon GEMIN5 upregulation supports the notion that this multifunctional protein has evolved as a gene expression balancer, consistent with its dual role as a member of the SMN complex and as a modulator of protein synthesis, ultimately impinging on cell homoeostasis.
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Affiliation(s)
| | - Salvador Abellan
- Genome Dynamics and Function, Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | | | - Juan Carlos Oliveros
- Bioinformatics for Genomics and Proteomics Unit, Centro Nacional de Biotecnologia. CSIC, Madrid, Spain
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Embarc-Buh A, Francisco-Velilla R, Garcia-Martin JA, Abellan S, Ramajo J, Martinez-Salas E. Gemin5-dependent RNA association with polysomes enables selective translation of ribosomal and histone mRNAs. Cell Mol Life Sci 2022; 79:490. [PMID: 35987821 PMCID: PMC9392717 DOI: 10.1007/s00018-022-04519-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/27/2022] [Accepted: 08/04/2022] [Indexed: 11/03/2022]
Abstract
AbstractSelective translation allows to orchestrate the expression of specific proteins in response to different signals through the concerted action of cis-acting elements and RNA-binding proteins (RBPs). Gemin5 is a ubiquitous RBP involved in snRNP assembly. In addition, Gemin5 regulates translation of different mRNAs through apparently opposite mechanisms of action. Here, we investigated the differential function of Gemin5 in translation by identifying at a genome-wide scale the mRNAs associated with polysomes. Among the mRNAs showing Gemin5-dependent enrichment in polysomal fractions, we identified a selective enhancement of specific transcripts. Comparison of the targets previously identified by CLIP methodologies with the polysome-associated transcripts revealed that only a fraction of the targets was enriched in polysomes. Two different subsets of these mRNAs carry unique cis-acting regulatory elements, the 5’ terminal oligopyrimidine tracts (5’TOP) and the histone stem-loop (hSL) structure at the 3’ end, respectively, encoding ribosomal proteins and histones. RNA-immunoprecipitation (RIP) showed that ribosomal and histone mRNAs coprecipitate with Gemin5. Furthermore, disruption of the TOP motif impaired Gemin5-RNA interaction, and functional analysis showed that Gemin5 stimulates translation of mRNA reporters bearing an intact TOP motif. Likewise, Gemin5 enhanced hSL-dependent mRNA translation. Thus, Gemin5 promotes polysome association of only a subset of its targets, and as a consequence, it favors translation of the ribosomal and the histone mRNAs. Together, the results presented here unveil Gemin5 as a novel translation regulator of mRNA subsets encoding proteins involved in fundamental cellular processes.
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11
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Francisco-Velilla R, Embarc-Buh A, Del Caño-Ochoa F, Abellan S, Vilar M, Alvarez S, Fernandez-Jaen A, Kour S, Rajan DS, Pandey UB, Ramón-Maiques S, Martinez-Salas E. Functional and structural deficiencies of Gemin5 variants associated with neurological disorders. Life Sci Alliance 2022; 5:5/7/e202201403. [PMID: 35393353 PMCID: PMC8989681 DOI: 10.26508/lsa.202201403] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 12/15/2022] Open
Abstract
Dysfunction of RNA-binding proteins is often linked to a wide range of human disease, particularly with neurological conditions. Gemin5 is a member of the survival of the motor neurons (SMN) complex, a ribosome-binding protein and a translation reprogramming factor. Recently, pathogenic mutations in Gemin5 have been reported, but the functional consequences of these variants remain elusive. Here, we report functional and structural deficiencies associated with compound heterozygosity variants within the Gemin5 gene found in patients with neurodevelopmental disorders. These clinical variants are located in key domains of Gemin5, the tetratricopeptide repeat (TPR)-like dimerization module and the noncanonical RNA-binding site 1 (RBS1). We show that the TPR-like variants disrupt protein dimerization, whereas the RBS1 variant confers protein instability. All mutants are defective in the interaction with protein networks involved in translation and RNA-driven pathways. Importantly, the TPR-like variants fail to associate with native ribosomes, hampering its involvement in translation control and establishing a functional difference with the wild-type protein. Our study provides insights into the molecular basis of disease associated with malfunction of the Gemin5 protein.
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Affiliation(s)
- Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Cientificas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain
| | - Azman Embarc-Buh
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Cientificas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain
| | - Francisco Del Caño-Ochoa
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Salvador Abellan
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Cientificas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain
| | - Marçal Vilar
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain
| | - Sara Alvarez
- New Integrated Medical Genetics (NIMGENETICS), Madrid, Spain
| | - Alberto Fernandez-Jaen
- Neuropediatric Department, Hospital Universitario Quirónsalud, Madrid, Spain.,School of Medicine, Universidad Europea de Madrid, Madrid, Spain
| | - Sukhleen Kour
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Deepa S Rajan
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Udai Bhan Pandey
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Santiago Ramón-Maiques
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Cientificas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain
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Rajan DS, Kour S, Fortuna TR, Cousin MA, Barnett SS, Niu Z, Babovic-Vuksanovic D, Klee EW, Kirmse B, Innes M, Rydning SL, Selmer KK, Vigeland MD, Erichsen AK, Nemeth AH, Millan F, DeVile C, Fawcett K, Legendre A, Sims D, Schnekenberg RP, Burglen L, Mercier S, Bakhtiari S, Francisco-Velilla R, Embarc-Buh A, Martinez-Salas E, Wigby K, Lenberg J, Friedman JR, Kruer MC, Pandey UB. Autosomal Recessive Cerebellar Atrophy and Spastic Ataxia in Patients With Pathogenic Biallelic Variants in GEMIN5. Front Cell Dev Biol 2022; 10:783762. [PMID: 35295849 PMCID: PMC8918504 DOI: 10.3389/fcell.2022.783762] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 01/17/2022] [Indexed: 01/01/2023] Open
Abstract
The hereditary ataxias are a heterogenous group of disorders with an increasing number of causative genes being described. Due to the clinical and genetic heterogeneity seen in these conditions, the majority of such individuals endure a diagnostic odyssey or remain undiagnosed. Defining the molecular etiology can bring insights into the responsible molecular pathways and eventually the identification of therapeutic targets. Here, we describe the identification of biallelic variants in the GEMIN5 gene among seven unrelated families with nine affected individuals presenting with spastic ataxia and cerebellar atrophy. GEMIN5, an RNA-binding protein, has been shown to regulate transcription and translation machinery. GEMIN5 is a component of small nuclear ribonucleoprotein (snRNP) complexes and helps in the assembly of the spliceosome complexes. We found that biallelic GEMIN5 variants cause structural abnormalities in the encoded protein and reduce expression of snRNP complex proteins in patient cells compared with unaffected controls. Finally, knocking out endogenous Gemin5 in mice caused early embryonic lethality, suggesting that Gemin5 expression is crucial for normal development. Our work further expands on the phenotypic spectrum associated with GEMIN5-related disease and implicates the role of GEMIN5 among patients with spastic ataxia, cerebellar atrophy, and motor predominant developmental delay.
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Affiliation(s)
- Deepa S. Rajan
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Sukhleen Kour
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Tyler R. Fortuna
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Margot A. Cousin
- Department of Center for Individualized Medicine, Mayo Clinic, Rochester, MN, United States
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, United States
| | - Sarah S. Barnett
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Zhiyv Niu
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States
| | - Dusica Babovic-Vuksanovic
- Department of Center for Individualized Medicine, Mayo Clinic, Rochester, MN, United States
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States
| | - Eric W. Klee
- Department of Center for Individualized Medicine, Mayo Clinic, Rochester, MN, United States
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, United States
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States
| | - Brian Kirmse
- Division of Genetics, University of Mississippi Medical Center, Jackson, MS, United States
| | - Micheil Innes
- Department of Medical Genetics and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | | | - Kaja K. Selmer
- Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital and the University of Oslo, Oslo, Norway
| | - Magnus Dehli Vigeland
- Department of Medical Genetics, Oslo University Hospital, and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | | | - Andrea H. Nemeth
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | | | | | - Katherine Fawcett
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- Department of Health Sciences, University of Leicester, Leicester, United Kingdom
| | - Adrien Legendre
- Laboratoire de biologie médicale multisites Seqoia—FMG2025, Paris, France
| | - David Sims
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Lydie Burglen
- Centre de Référence des Malformations et Maladies Congénitales du Cervelet et Laboratoire de Neurogénétique Moléculaire, Département de Génétique, AP-HP. Sorbonne Université, Hôpital Trousseau, Paris, France
- Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, Paris, France
| | - Sandra Mercier
- CHU Nantes, Service de génétique médicale, Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Nantes, France
- Nantes Université, CNRS, INSERM, l’institut du thorax, Nantes, France
| | - Somayeh Bakhtiari
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ, United States
- Departments of Child Health, Neurology, Cellular and Molecular Medicine and Program in Genetics, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, United States
| | | | - Azman Embarc-Buh
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | | | - Kristen Wigby
- Department of Pediatrics, University of California San Diego, San Diego, CA, United States
- Rady Children’s Institute for Genomic Medicine, San Diego, CA, United States
| | - Jerica Lenberg
- Rady Children’s Institute for Genomic Medicine, San Diego, CA, United States
| | - Jennifer R. Friedman
- Department of Neurosciences, University of California San Diego, San Diego, CA, United States
- Department of Pediatrics, University of California San Diego, San Diego, CA, United States
- Rady Children’s Institute for Genomic Medicine, San Diego, CA, United States
| | - Michael C. Kruer
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ, United States
- Departments of Child Health, Neurology, Cellular and Molecular Medicine and Program in Genetics, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, United States
| | - Udai Bhan Pandey
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
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13
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Liu X, Zhang W, Jing C, Gao L, Fu C, Ren C, Hao Y, Cao M, Ma K, Pan W, Li D. Mutation of Gemin5 Causes Defective Hematopoietic Stem/Progenitor Cells Proliferation in Zebrafish Embryonic Hematopoiesis. Front Cell Dev Biol 2021; 9:670654. [PMID: 33996826 PMCID: PMC8120239 DOI: 10.3389/fcell.2021.670654] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/13/2021] [Indexed: 12/11/2022] Open
Abstract
Fate determination and expansion of Hematopoietic Stem and Progenitor Cells (HSPCs) is tightly regulated on both transcriptional and post-transcriptional level. Although transcriptional regulation of HSPCs have achieved a lot of advances, its post-transcriptional regulation remains largely underexplored. The small size and high fecundity of zebrafish makes it extraordinarily suitable to explore novel genes playing key roles in definitive hematopoiesis by large-scale forward genetics screening. Here, we reported a novel zebrafish mutant line gemin5 cas008 with a point mutation in gemin5 gene obtained by ENU mutagenesis and genetic screening, causing an earlier stop codon next to the fifth WD repeat. Gemin5 is an RNA-binding protein with multifunction in post-transcriptional regulation, such as regulating the biogenesis of snRNPs, alternative splicing, stress response, and translation control. The mutants displayed specific deficiency in definitive hematopoiesis without obvious defects during primitive hematopoiesis. Further analysis showed the impaired definitive hematopoiesis was due to defective proliferation of HSPCs. Overall, our results indicate that Gemin5 performs an essential role in regulating HSPCs proliferation.
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Affiliation(s)
- Xiaofen Liu
- Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenjuan Zhang
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Changbin Jing
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Lei Gao
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Cong Fu
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Chunguang Ren
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Yimei Hao
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Mengye Cao
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Ke Ma
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
- Clinical Research and Translation Center, The First Affiliated Hospital of Fujian Medical University, Fujian, China
| | - Weijun Pan
- Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Dantong Li
- Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
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14
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Emerging Roles of Gemin5: From snRNPs Assembly to Translation Control. Int J Mol Sci 2020; 21:ijms21113868. [PMID: 32485878 PMCID: PMC7311978 DOI: 10.3390/ijms21113868] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/22/2020] [Accepted: 05/27/2020] [Indexed: 02/07/2023] Open
Abstract
RNA-binding proteins (RBPs) play a pivotal role in the lifespan of RNAs. The disfunction of RBPs is frequently the cause of cell disorders which are incompatible with life. Furthermore, the ordered assembly of RBPs and RNAs in ribonucleoprotein (RNP) particles determines the function of biological complexes, as illustrated by the survival of the motor neuron (SMN) complex. Defects in the SMN complex assembly causes spinal muscular atrophy (SMA), an infant invalidating disease. This multi-subunit chaperone controls the assembly of small nuclear ribonucleoproteins (snRNPs), which are the critical components of the splicing machinery. However, the functional and structural characterization of individual members of the SMN complex, such as SMN, Gemin3, and Gemin5, have accumulated evidence for the additional roles of these proteins, unveiling their participation in other RNA-mediated events. In particular, Gemin5 is a multidomain protein that comprises tryptophan-aspartic acid (WD) repeat motifs at the N-terminal region, a dimerization domain at the middle region, and a non-canonical RNA-binding domain at the C-terminal end of the protein. Beyond small nuclear RNA (snRNA) recognition, Gemin5 interacts with a selective group of mRNA targets in the cell environment and plays a key role in reprogramming translation depending on the RNA partner and the cellular conditions. Here, we review recent studies on the SMN complex, with emphasis on the individual components regarding their involvement in cellular processes critical for cell survival.
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15
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Moreno-Morcillo M, Francisco-Velilla R, Embarc-Buh A, Fernández-Chamorro J, Ramón-Maiques S, Martinez-Salas E. Structural basis for the dimerization of Gemin5 and its role in protein recruitment and translation control. Nucleic Acids Res 2020; 48:788-801. [PMID: 31799608 PMCID: PMC6954437 DOI: 10.1093/nar/gkz1126] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 11/12/2019] [Accepted: 11/18/2019] [Indexed: 12/21/2022] Open
Abstract
In all organisms, a selected type of proteins accomplishes critical roles in cellular processes that govern gene expression. The multifunctional protein Gemin5 cooperates in translation control and ribosome binding, besides acting as the RNA-binding protein of the survival of motor neuron (SMN) complex. While these functions reside on distinct domains located at each end of the protein, the structure and function of the middle region remained unknown. Here, we solved the crystal structure of an extended tetratricopeptide (TPR)-like domain in human Gemin5 that self-assembles into a previously unknown canoe-shaped dimer. We further show that the dimerization module is functional in living cells driving the interaction between the viral-induced cleavage fragment p85 and the full-length Gemin5, which anchors splicing and translation members. Disruption of the dimerization surface by a point mutation in the TPR-like domain prevents this interaction and also abrogates translation enhancement induced by p85. The characterization of this unanticipated dimerization domain provides the structural basis for a role of the middle region of Gemin5 as a central hub for protein-protein interactions.
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Affiliation(s)
- María Moreno-Morcillo
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049 Madrid, Spain
| | | | - Azman Embarc-Buh
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049 Madrid, Spain
| | | | - Santiago Ramón-Maiques
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049 Madrid, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)- Instituto de Salud Carlos III, Valencia, Spain
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16
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Francisco-Velilla R, Fernandez-Chamorro J, Dotu I, Martinez-Salas E. The landscape of the non-canonical RNA-binding site of Gemin5 unveils a feedback loop counteracting the negative effect on translation. Nucleic Acids Res 2019; 46:7339-7353. [PMID: 29771365 PMCID: PMC6101553 DOI: 10.1093/nar/gky361] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 05/08/2018] [Indexed: 01/01/2023] Open
Abstract
Gemin5 is a predominantly cytoplasmic protein that downregulates translation, beyond controlling snRNPs assembly. The C-terminal region harbors a non-canonical RNA-binding site consisting of two domains, RBS1 and RBS2, which differ in RNA-binding capacity and the ability to modulate translation. Here, we show that these domains recognize distinct RNA targets in living cells. Interestingly, the most abundant and exclusive RNA target of the RBS1 domain was Gemin5 mRNA. Biochemical and functional characterization of this target demonstrated that RBS1 polypeptide physically interacts with a predicted thermodynamically stable stem–loop upregulating mRNA translation, thereby counteracting the negative effect of Gemin5 protein on global protein synthesis. In support of this result, destabilization of the stem–loop impairs the stimulatory effect on translation. Moreover, RBS1 stimulates translation of the endogenous Gemin5 mRNA. Hence, although the RBS1 domain downregulates global translation, it positively enhances translation of RNA targets carrying thermodynamically stable secondary structure motifs. This mechanism allows fine-tuning the availability of Gemin5 to play its multiple roles in gene expression control.
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Affiliation(s)
| | | | - Ivan Dotu
- Pompeu Fabra University (UPF), 08003 Barcelona, Spain.,IMIM - Hospital del Mar Medical Research Institute, 08003 Barcelona, Spain
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17
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Composition of the Survival Motor Neuron (SMN) Complex in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2019; 9:491-503. [PMID: 30563832 PMCID: PMC6385987 DOI: 10.1534/g3.118.200874] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Spinal Muscular Atrophy (SMA) is caused by homozygous mutations in the human survival motor neuron 1 (SMN1) gene. SMN protein has a well-characterized role in the biogenesis of small nuclear ribonucleoproteins (snRNPs), core components of the spliceosome. SMN is part of an oligomeric complex with core binding partners, collectively called Gemins. Biochemical and cell biological studies demonstrate that certain Gemins are required for proper snRNP assembly and transport. However, the precise functions of most Gemins are unknown. To gain a deeper understanding of the SMN complex in the context of metazoan evolution, we investigated its composition in Drosophila melanogaster Using transgenic flies that exclusively express Flag-tagged SMN from its native promoter, we previously found that Gemin2, Gemin3, Gemin5, and all nine classical Sm proteins, including Lsm10 and Lsm11, co-purify with SMN. Here, we show that CG2941 is also highly enriched in the pulldown. Reciprocal co-immunoprecipitation reveals that epitope-tagged CG2941 interacts with endogenous SMN in Schneider2 cells. Bioinformatic comparisons show that CG2941 shares sequence and structural similarity with metazoan Gemin4. Additional analysis shows that three other genes (CG14164, CG31950 and CG2371) are not orthologous to Gemins 6-7-8, respectively, as previously suggested. In D.melanogaster, CG2941 is located within an evolutionarily recent genomic triplication with two other nearly identical paralogous genes (CG32783 and CG32786). RNAi-mediated knockdown of CG2941 and its two close paralogs reveals that Gemin4 is essential for organismal viability.
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18
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Aquilina B, Cauchi RJ. Modelling motor neuron disease in fruit flies: Lessons from spinal muscular atrophy. J Neurosci Methods 2018; 310:3-11. [DOI: 10.1016/j.jneumeth.2018.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 04/06/2018] [Accepted: 04/07/2018] [Indexed: 12/25/2022]
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19
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A cell surface protein controls endocrine ring gland morphogenesis and steroid production. Dev Biol 2018; 445:16-28. [PMID: 30367846 DOI: 10.1016/j.ydbio.2018.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/09/2018] [Accepted: 10/15/2018] [Indexed: 12/14/2022]
Abstract
Identification of signals for systemic adaption of hormonal regulation would help to understand the crosstalk between cells and environmental cues contributing to growth, metabolic homeostasis and development. Physiological states are controlled by precise pulsatile hormonal release, including endocrine steroids in human and ecdysteroids in insects. We show in Drosophila that regulation of genes that control biosynthesis and signaling of the steroid hormone ecdysone, a central regulator of developmental progress, depends on the extracellular matrix protein Obstructor-A (Obst-A). Ecdysone is produced by the prothoracic gland (PG), where sensory neurons projecting axons from the brain integrate stimuli for endocrine control. By defining the extracellular surface, Obst-A promotes morphogenesis and axonal growth in the PG. This process requires Obst-A-matrix reorganization by Clathrin/Wurst-mediated endocytosis. Our data identifies the extracellular matrix as essential for endocrine ring gland function, which coordinates physiology, axon morphogenesis, and developmental programs. As Obst-A and Wurst homologs are found among all arthropods, we propose that this mechanism is evolutionary conserved.
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20
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Jha NN, Kim JK, Monani UR. Motor neuron biology and disease: A current perspective on infantile-onset spinal muscular atrophy. FUTURE NEUROLOGY 2018; 13:161-172. [PMID: 31396020 DOI: 10.2217/fnl-2018-0008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Infantile-onset spinal muscular atrophy (SMA) is a prototypical disease in which to investigate selective neurodegenerative phenotypes. Caused by low levels of the ubiquitously expressed Survival Motor Neuron (SMN) protein, the disease mainly targets the spinal motor neurons. This selective phenotype remains largely unexplained, but has not hindered the development of SMN repletion as a means to a treatment. Here we chronicle recent advances in the area of SMA biology. We provide a brief background to the disease, highlight major advances that have shaped our current understanding of SMA, trace efforts to treat the condition, discuss the outcome of two promising new therapies and conclude by considering contemporary as well as new challenges stemming from recent successes within the field.
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Affiliation(s)
- Narendra N Jha
- Department of Pathology & Cell Biology, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032.,Center for Motor Neuron Biology & Disease, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032
| | - Jeong-Ki Kim
- Department of Pathology & Cell Biology, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032.,Center for Motor Neuron Biology & Disease, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032
| | - Umrao R Monani
- Department of Pathology & Cell Biology, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032.,Department of Neurology, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032.,Center for Motor Neuron Biology & Disease, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032
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21
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Gray KM, Kaifer KA, Baillat D, Wen Y, Bonacci TR, Ebert AD, Raimer AC, Spring AM, Have ST, Glascock JJ, Gupta K, Van Duyne GD, Emanuele MJ, Lamond AI, Wagner EJ, Lorson CL, Matera AG. Self-oligomerization regulates stability of survival motor neuron protein isoforms by sequestering an SCF Slmb degron. Mol Biol Cell 2018; 29:96-110. [PMID: 29167380 PMCID: PMC5909936 DOI: 10.1091/mbc.e17-11-0627] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 11/14/2017] [Indexed: 12/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous mutations in human SMN1 Expression of a duplicate gene (SMN2) primarily results in skipping of exon 7 and production of an unstable protein isoform, SMNΔ7. Although SMN2 exon skipping is the principal contributor to SMA severity, mechanisms governing stability of survival motor neuron (SMN) isoforms are poorly understood. We used a Drosophila model system and label-free proteomics to identify the SCFSlmb ubiquitin E3 ligase complex as a novel SMN binding partner. SCFSlmb interacts with a phosphor degron embedded within the human and fruitfly SMN YG-box oligomerization domains. Substitution of a conserved serine (S270A) interferes with SCFSlmb binding and stabilizes SMNΔ7. SMA-causing missense mutations that block multimerization of full-length SMN are also stabilized in the degron mutant background. Overexpression of SMNΔ7S270A, but not wild-type (WT) SMNΔ7, provides a protective effect in SMA model mice and human motor neuron cell culture systems. Our findings support a model wherein the degron is exposed when SMN is monomeric and sequestered when SMN forms higher-order multimers.
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Affiliation(s)
- Kelsey M Gray
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Kevin A Kaifer
- Molecular Pathogenesis and Therapeutics Program, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - David Baillat
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550
| | - Ying Wen
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Thomas R Bonacci
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599
| | - Allison D Ebert
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Amanda C Raimer
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Ashlyn M Spring
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
| | - Sara Ten Have
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD15EH, UK
| | - Jacqueline J Glascock
- Molecular Pathogenesis and Therapeutics Program, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - Kushol Gupta
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Gregory D Van Duyne
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Michael J Emanuele
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599
| | - Angus I Lamond
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD15EH, UK
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77550
| | - Christian L Lorson
- Molecular Pathogenesis and Therapeutics Program, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - A Gregory Matera
- Curriculum in Genetics and Molecular Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program in Biological and Genome Sciences, Department of Biology and Department of Genetics, University of North Carolina, Chapel Hill, NC 27599
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22
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Francisco-Velilla R, Fernandez-Chamorro J, Ramajo J, Martinez-Salas E. The RNA-binding protein Gemin5 binds directly to the ribosome and regulates global translation. Nucleic Acids Res 2016; 44:8335-51. [PMID: 27507887 PMCID: PMC5041490 DOI: 10.1093/nar/gkw702] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/31/2016] [Indexed: 12/21/2022] Open
Abstract
RNA-binding proteins (RBPs) play crucial roles in all organisms. The protein Gemin5 harbors two functional domains. The N-terminal domain binds to snRNAs targeting them for snRNPs assembly, while the C-terminal domain binds to IRES elements through a non-canonical RNA-binding site. Here we report a comprehensive view of the Gemin5 interactome; most partners copurified with the N-terminal domain via RNA bridges. Notably, Gemin5 sediments with the subcellular ribosome fraction, and His-Gemin5 binds to ribosome particles via its N-terminal domain. The interaction with the ribosome was lost in F381A and Y474A Gemin5 mutants, but not in W14A and Y15A. Moreover, the ribosomal proteins L3 and L4 bind directly with Gemin5, and conversely, Gemin5 mutants impairing the binding to the ribosome are defective in the interaction with L3 and L4. The overall polysome profile was affected by Gemin5 depletion or overexpression, concomitant to an increase or a decrease, respectively, of global protein synthesis. Gemin5, and G5-Nter as well, were detected on the polysome fractions. These results reveal the ribosome-binding capacity of the N-ter moiety, enabling Gemin5 to control global protein synthesis. Our study uncovers a crosstalk between this protein and the ribosome, and provides support for the view that Gemin5 may control translation elongation.
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Affiliation(s)
| | | | - Jorge Ramajo
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049-Madrid, Spain
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23
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Xie XJ, Hsu FN, Gao X, Xu W, Ni JQ, Xing Y, Huang L, Hsiao HC, Zheng H, Wang C, Zheng Y, Xiaoli AM, Yang F, Bondos SE, Ji JY. CDK8-Cyclin C Mediates Nutritional Regulation of Developmental Transitions through the Ecdysone Receptor in Drosophila. PLoS Biol 2015. [PMID: 26222308 PMCID: PMC4519132 DOI: 10.1371/journal.pbio.1002207] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The steroid hormone ecdysone and its receptor (EcR) play critical roles in orchestrating developmental transitions in arthropods. However, the mechanism by which EcR integrates nutritional and developmental cues to correctly activate transcription remains poorly understood. Here, we show that EcR-dependent transcription, and thus, developmental timing in Drosophila, is regulated by CDK8 and its regulatory partner Cyclin C (CycC), and the level of CDK8 is affected by nutrient availability. We observed that cdk8 and cycC mutants resemble EcR mutants and EcR-target genes are systematically down-regulated in both mutants. Indeed, the ability of the EcR-Ultraspiracle (USP) heterodimer to bind to polytene chromosomes and the promoters of EcR target genes is also diminished. Mass spectrometry analysis of proteins that co-immunoprecipitate with EcR and USP identified multiple Mediator subunits, including CDK8 and CycC. Consistently, CDK8-CycC interacts with EcR-USP in vivo; in particular, CDK8 and Med14 can directly interact with the AF1 domain of EcR. These results suggest that CDK8-CycC may serve as transcriptional cofactors for EcR-dependent transcription. During the larval–pupal transition, the levels of CDK8 protein positively correlate with EcR and USP levels, but inversely correlate with the activity of sterol regulatory element binding protein (SREBP), the master regulator of intracellular lipid homeostasis. Likewise, starvation of early third instar larvae precociously increases the levels of CDK8, EcR and USP, yet down-regulates SREBP activity. Conversely, refeeding the starved larvae strongly reduces CDK8 levels but increases SREBP activity. Importantly, these changes correlate with the timing for the larval–pupal transition. Taken together, these results suggest that CDK8-CycC links nutrient intake to developmental transitions (EcR activity) and fat metabolism (SREBP activity) during the larval–pupal transition. During the larval-pupal transition in Drosophila, CDK8-CycC helps to link nutrient intake to development by activating ecdysone receptor-dependent transcription and to fat metabolism by inhibiting SREBP-activated gene expression. Arthropods are estimated to account for over 80% of animal species on earth. Characterized by their rigid exoskeletons, juvenile arthropods must periodically shed their thick outer cuticles by molting in order to grow. The steroid hormone ecdysone plays an essential role in regulating the timing of developmental transitions, but exactly how ecdysone and its receptor EcR activates transcription correctly after integrating nutritional and developmental cues remains unknown. Our developmental genetic analyses of two Drosophila mutants, cdk8 and cycC, show that they are lethal during the prepupal stage, with aberrant accumulation of fat and a severely delayed larval–pupal transition. As we have reported previously, CDK8-CycC inhibits fat accumulation by directly inactivating SREBP, a master transcription factor that controls the expression of lipogenic genes, which explains the abnormal fat accumulation in the cdk8 and cycC mutants. We find that CDK8 and CycC are required for EcR to bind to its target genes, serving as transcriptional cofactors for EcR-dependent gene expression. The expression of EcR target genes is compromised in cdk8 and cycC mutants and underpins the retarded pupariation phenotype. Starvation of feeding larvae precociously up-regulates CDK8 and EcR, prematurely down-regulates SREBP activity, and leads to early pupariation, whereas re-feeding starved larvae has opposite effects. Taken together, these results suggest that CDK8 and CycC play important roles in coordinating nutrition intake with fat metabolism by directly inhibiting SREBP-dependent gene expression and regulating developmental timing by activating EcR-dependent transcription in Drosophila.
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Affiliation(s)
- Xiao-Jun Xie
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Fu-Ning Hsu
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Xinsheng Gao
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Los Angeles, United States of America
| | - Jian-Quan Ni
- Gene Regulatory Laboratory, School of Medicine, Tsinghua University, Beijing, China
| | - Yue Xing
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Liying Huang
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Los Angeles, United States of America
| | - Hao-Ching Hsiao
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Haiyan Zheng
- Biological Mass Spectrometry Facility, Robert Wood Johnson Medical School and Rutgers, the State University of New Jersey, Frelinghuysen Road, Piscataway, New Jersey, United States of America
| | - Chenguang Wang
- Key Laboratory of Tianjin Radiation and Molecular Nuclear Medicine; Institute of Radiation Medicine, Peking Union Medical College & Chinese Academy of Medical Sciences, Tianjin, China
| | - Yani Zheng
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Alus M. Xiaoli
- Department of Medicine, Division of Endocrinology, Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Fajun Yang
- Department of Medicine, Division of Endocrinology, Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Sarah E. Bondos
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
- Department of Biosciences, Rice University, Houston, Texas, United States of America
| | - Jun-Yuan Ji
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
- * E-mail:
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24
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Borg RM, Bordonne R, Vassallo N, Cauchi RJ. Genetic Interactions between the Members of the SMN-Gemins Complex in Drosophila. PLoS One 2015; 10:e0130974. [PMID: 26098872 PMCID: PMC4476591 DOI: 10.1371/journal.pone.0130974] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/27/2015] [Indexed: 11/19/2022] Open
Abstract
The SMN-Gemins complex is composed of Gemins 2–8, Unrip and the survival motor neuron (SMN) protein. Limiting levels of SMN result in the neuromuscular disorder, spinal muscular atrophy (SMA), which is presently untreatable. The most-documented function of the SMN-Gemins complex concerns the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs). Despite multiple genetic studies, the Gemin proteins have not been identified as prominent modifiers of SMN-associated mutant phenotypes. In the present report, we make use of the Drosophila model organism to investigate whether viability and motor phenotypes associated with a hypomorphic Gemin3 mutant are enhanced by changes in the levels of SMN, Gemin2 and Gemin5 brought about by various genetic manipulations. We show a modifier effect by all three members of the minimalistic fly SMN-Gemins complex within the muscle compartment of the motor unit. Interestingly, muscle-specific overexpression of Gemin2 was by itself sufficient to depress normal motor function and its enhanced upregulation in all tissues leads to a decline in fly viability. The toxicity associated with increased Gemin2 levels is conserved in the yeast S. pombe in which we find that the cytoplasmic retention of Sm proteins, likely reflecting a block in the snRNP assembly pathway, is a contributing factor. We propose that a disruption in the normal stoichiometry of the SMN-Gemins complex depresses its function with consequences that are detrimental to the motor system.
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Affiliation(s)
- Rebecca M. Borg
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta GC
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Université Montpellier 1 and 2, Montpellier, France
| | - Rémy Bordonne
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Université Montpellier 1 and 2, Montpellier, France
| | - Neville Vassallo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta GC
| | - Ruben J. Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta GC
- * E-mail:
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25
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Kapheim KM, Pan H, Li C, Salzberg SL, Puiu D, Magoc T, Robertson HM, Hudson ME, Venkat A, Fischman BJ, Hernandez A, Yandell M, Ence D, Holt C, Yocum GD, Kemp WP, Bosch J, Waterhouse RM, Zdobnov EM, Stolle E, Kraus FB, Helbing S, Moritz RFA, Glastad KM, Hunt BG, Goodisman MAD, Hauser F, Grimmelikhuijzen CJP, Pinheiro DG, Nunes FMF, Soares MPM, Tanaka ÉD, Simões ZLP, Hartfelder K, Evans JD, Barribeau SM, Johnson RM, Massey JH, Southey BR, Hasselmann M, Hamacher D, Biewer M, Kent CF, Zayed A, Blatti C, Sinha S, Johnston JS, Hanrahan SJ, Kocher SD, Wang J, Robinson GE, Zhang G. Social evolution. Genomic signatures of evolutionary transitions from solitary to group living. Science 2015; 348:1139-43. [PMID: 25977371 PMCID: PMC5471836 DOI: 10.1126/science.aaa4788] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 05/06/2015] [Indexed: 12/14/2022]
Abstract
The evolution of eusociality is one of the major transitions in evolution, but the underlying genomic changes are unknown. We compared the genomes of 10 bee species that vary in social complexity, representing multiple independent transitions in social evolution, and report three major findings. First, many important genes show evidence of neutral evolution as a consequence of relaxed selection with increasing social complexity. Second, there is no single road map to eusociality; independent evolutionary transitions in sociality have independent genetic underpinnings. Third, though clearly independent in detail, these transitions do have similar general features, including an increase in constrained protein evolution accompanied by increases in the potential for gene regulation and decreases in diversity and abundance of transposable elements. Eusociality may arise through different mechanisms each time, but would likely always involve an increase in the complexity of gene networks.
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Affiliation(s)
- Karen M Kapheim
- Carl R. WoeseInstitute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Biology, Utah State University, Logan, UT 84322, USA.
| | - Hailin Pan
- China National GeneBank, BGI-Shenzhen, Shenzhen, 518083, China
| | - Cai Li
- China National GeneBank, BGI-Shenzhen, Shenzhen, 518083, China. Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, 1350, Denmark
| | - Steven L Salzberg
- Departments of Biomedical Engineering, Computer Science, and Biostatistics, Johns Hopkins University, Baltimore, MD 21218, USA. Center for Computational Biology, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daniela Puiu
- Center for Computational Biology, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Tanja Magoc
- Center for Computational Biology, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hugh M Robertson
- Carl R. WoeseInstitute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Matthew E Hudson
- Carl R. WoeseInstitute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Aarti Venkat
- Carl R. WoeseInstitute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Brielle J Fischman
- Carl R. WoeseInstitute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Program in Ecology and Evolutionary Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Biology, Hobart and William Smith Colleges, Geneva, NY 14456, USA
| | - Alvaro Hernandez
- Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Mark Yandell
- Department of Human Genetics, Eccles Institute of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA. USTAR Center for Genetic Discovery, University of Utah, Salt Lake City, UT 84112, USA
| | - Daniel Ence
- Department of Human Genetics, Eccles Institute of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Carson Holt
- Department of Human Genetics, Eccles Institute of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA. USTAR Center for Genetic Discovery, University of Utah, Salt Lake City, UT 84112, USA
| | - George D Yocum
- U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) Red River Valley Agricultural Research Center, Biosciences Research Laboratory, Fargo, ND 58102, USA
| | - William P Kemp
- U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) Red River Valley Agricultural Research Center, Biosciences Research Laboratory, Fargo, ND 58102, USA
| | - Jordi Bosch
- Center for Ecological Research and Forestry Applications (CREAF), Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain
| | - Robert M Waterhouse
- Department of Genetic Medicine and Development, University of Geneva Medical School, 1211 Geneva, Switzerland. Swiss Institute of Bioinformatics, 1211 Geneva, Switzerland. Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA. The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Evgeny M Zdobnov
- Department of Genetic Medicine and Development, University of Geneva Medical School, 1211 Geneva, Switzerland. Swiss Institute of Bioinformatics, 1211 Geneva, Switzerland
| | - Eckart Stolle
- Institute of Biology, Department Zoology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 4, D-06099 Halle (Saale), Germany. Queen Mary University of London, School of Biological and Chemical Sciences Organismal Biology Research Group, London E1 4NS, UK
| | - F Bernhard Kraus
- Institute of Biology, Department Zoology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 4, D-06099 Halle (Saale), Germany. Department of Laboratory Medicine, University Hospital Halle, Ernst Grube Strasse 40, D-06120 Halle (Saale), Germany
| | - Sophie Helbing
- Institute of Biology, Department Zoology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 4, D-06099 Halle (Saale), Germany
| | - Robin F A Moritz
- Institute of Biology, Department Zoology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 4, D-06099 Halle (Saale), Germany. German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, 04103 Leipzig, Germany
| | - Karl M Glastad
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Brendan G Hunt
- Department of Entomology, University of Georgia, Griffin, GA 30223, USA
| | | | - Frank Hauser
- Center for Functional and Comparative Insect Genomics, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Cornelis J P Grimmelikhuijzen
- Center for Functional and Comparative Insect Genomics, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Daniel Guariz Pinheiro
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP, Brazil. Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (UNESP), 14884-900 Jaboticabal, SP, Brazil
| | - Francis Morais Franco Nunes
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, 13565-905 São Carlos, SP, Brazil
| | - Michelle Prioli Miranda Soares
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP, Brazil
| | - Érica Donato Tanaka
- Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | - Zilá Luz Paulino Simões
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP, Brazil
| | - Klaus Hartfelder
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | - Jay D Evans
- USDA-ARS Bee Research Lab, Beltsville, MD 20705 USA
| | - Seth M Barribeau
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Reed M Johnson
- Department of Entomology, Ohio Agricultural Research and Development Center, Ohio State University, Wooster, OH 44691, USA
| | - Jonathan H Massey
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Bruce R Southey
- Department of Animal Sciences, University of Illinois, Urbana, IL 61801, USA
| | - Martin Hasselmann
- Department of Population Genomics, Institute of Animal Husbandry and Animal Breeding, University of Hohenheim, Germany
| | - Daniel Hamacher
- Department of Population Genomics, Institute of Animal Husbandry and Animal Breeding, University of Hohenheim, Germany
| | - Matthias Biewer
- Department of Population Genomics, Institute of Animal Husbandry and Animal Breeding, University of Hohenheim, Germany
| | - Clement F Kent
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada. Janelia Farm Research Campus, Howard Hughes Medical Institue, Ashburn, VA 20147, USA
| | - Amro Zayed
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| | - Charles Blatti
- Carl R. WoeseInstitute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Saurabh Sinha
- Carl R. WoeseInstitute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - J Spencer Johnston
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
| | - Shawn J Hanrahan
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
| | - Sarah D Kocher
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Jun Wang
- China National GeneBank, BGI-Shenzhen, Shenzhen, 518083, China. Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark. Princess Al Jawhara Center of Excellence in the Research of Hereditary Disorders, King Abdulaziz University, Jeddah 21589, Saudi Arabia. Macau University of Science and Technology, Avenida Wai long, Taipa, Macau 999078, China. Department of Medicine, University of Hong Kong, Hong Kong.
| | - Gene E Robinson
- Carl R. WoeseInstitute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Center for Advanced Study Professor in Entomology and Neuroscience, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Guojie Zhang
- China National GeneBank, BGI-Shenzhen, Shenzhen, 518083, China. Centre for Social Evolution, Department of Biology, Universitetsparken 15, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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Piñeiro D, Fernandez-Chamorro J, Francisco-Velilla R, Martinez-Salas E. Gemin5: A Multitasking RNA-Binding Protein Involved in Translation Control. Biomolecules 2015; 5:528-44. [PMID: 25898402 PMCID: PMC4496684 DOI: 10.3390/biom5020528] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 04/01/2015] [Accepted: 04/09/2015] [Indexed: 12/31/2022] Open
Abstract
Gemin5 is a RNA-binding protein (RBP) that was first identified as a peripheral component of the survival of motor neurons (SMN) complex. This predominantly cytoplasmic protein recognises the small nuclear RNAs (snRNAs) through its WD repeat domains, allowing assembly of the SMN complex into small nuclear ribonucleoproteins (snRNPs). Additionally, the amino-terminal end of the protein has been reported to possess cap-binding capacity and to interact with the eukaryotic initiation factor 4E (eIF4E). Gemin5 was also shown to downregulate translation, to be a substrate of the picornavirus L protease and to interact with viral internal ribosome entry site (IRES) elements via a bipartite non-canonical RNA-binding site located at its carboxy-terminal end. These features link Gemin5 with translation control events. Thus, beyond its role in snRNPs biogenesis, Gemin5 appears to be a multitasking protein cooperating in various RNA-guided processes. In this review, we will summarise current knowledge of Gemin5 functions. We will discuss the involvement of the protein on translation control and propose a model to explain how the proteolysis fragments of this RBP in picornavirus-infected cells could modulate protein synthesis.
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Affiliation(s)
- David Piñeiro
- Medical Research Council Toxicology Unit, Lancaster Rd, Leicester LE1 9HN, UK.
| | - Javier Fernandez-Chamorro
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Nicolas Cabrera 1, Madrid 28049, Spain.
| | - Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Nicolas Cabrera 1, Madrid 28049, Spain.
| | - Encarna Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Nicolas Cabrera 1, Madrid 28049, Spain.
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27
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Borg R, Cauchi RJ. GEMINs: potential therapeutic targets for spinal muscular atrophy? Front Neurosci 2014; 8:325. [PMID: 25360080 PMCID: PMC4197776 DOI: 10.3389/fnins.2014.00325] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/26/2014] [Indexed: 01/28/2023] Open
Abstract
The motor neuron degenerative disease spinal muscular atrophy (SMA) remains one of the most frequently inherited causes of infant mortality. Afflicted patients loose the survival motor neuron 1 (SMN1) gene but retain one or more copies of SMN2, a homolog that is incorrectly spliced. Primary treatment strategies for SMA aim at boosting SMN protein levels, which are insufficient in patients. SMN is known to partner with a set of diverse proteins collectively known as GEMINs to form a macromolecular complex. The SMN-GEMINs complex is indispensible for chaperoning the assembly of small nuclear ribonucleoproteins (snRNPs), which are key for pre-mRNA splicing. Pharmaceutics that alleviate the neuromuscular phenotype by restoring the fundamental function of SMN without augmenting its levels are also crucial in the development of an effective treatment. Their use as an adjunct therapy is predicted to enhance benefit to patients. Inspired by the surprising discovery revealing a premier role for GEMINs in snRNP biogenesis together with in vivo studies documenting their requirement for the correct function of the motor system, this review speculates on whether GEMINs constitute valid targets for SMA therapeutic development.
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Affiliation(s)
- Rebecca Borg
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta Msida, Malta
| | - Ruben J Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta Msida, Malta
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28
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Cauchi RJ. Gem depletion: amyotrophic lateral sclerosis and spinal muscular atrophy crossover. CNS Neurosci Ther 2014; 20:574-81. [PMID: 24645792 DOI: 10.1111/cns.12242] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 01/25/2014] [Accepted: 01/27/2014] [Indexed: 12/22/2022] Open
Abstract
The determining factor of spinal muscular atrophy (SMA), the most common motor neuron degenerative disease of childhood, is the survival motor neuron (SMN) protein. SMN and its Gemin associates form a complex that is indispensible for the biogenesis of small nuclear ribonucleoproteins (snRNPs), which constitute the building blocks of spliceosomes. It is as yet unclear whether a decreased capacity of SMN in snRNP assembly, and, hence, transcriptome abnormalities, account for the specific neuromuscular phenotype in SMA. Across metazoa, the SMN-Gemins complex concentrates in multiple nuclear gems that frequently neighbour or overlap Cajal bodies. The number of gems has long been known to be a faithful indicator of SMN levels, which are linked to SMA severity. Intriguingly, a flurry of recent studies have revealed that depletion of this nuclear structure is also a signature feature of amyotrophic lateral sclerosis (ALS), the most common adult-onset motor neuron disease. This review discusses such a surprising crossover in addition to highlighting the most recent work on the intricate world of spliceosome building, which seems to be at the heart of motor neuron physiology and survival.
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Affiliation(s)
- Ruben J Cauchi
- Department of Physiology and Biochemistry, University of Malta, Msida 2080, Malta
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29
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The Gemin associates of survival motor neuron are required for motor function in Drosophila. PLoS One 2013; 8:e83878. [PMID: 24391840 PMCID: PMC3877121 DOI: 10.1371/journal.pone.0083878] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 11/09/2013] [Indexed: 12/13/2022] Open
Abstract
Membership of the survival motor neuron (SMN) complex extends to nine factors, including the SMN protein, the product of the spinal muscular atrophy (SMA) disease gene, Gemins 2-8 and Unrip. The best-characterised function of this macromolecular machine is the assembly of the Sm-class of uridine-rich small nuclear ribonucleoprotein (snRNP) particles and each SMN complex member has a key role during this process. So far, however, only little is known about the function of the individual Gemin components in vivo. Here, we make use of the Drosophila model organism to uncover loss-of-function phenotypes of Gemin2, Gemin3 and Gemin5, which together with SMN form the minimalistic fly SMN complex. We show that ectopic overexpression of the dead helicase Gem3(ΔN) mutant or knockdown of Gemin3 result in similar motor phenotypes, when restricted to muscle, and in combination cause lethality, hence suggesting that Gem3(ΔN) overexpression mimics a loss-of-function. Based on the localisation pattern of Gem3(ΔN), we predict that the nucleus is the primary site of the antimorphic or dominant-negative mechanism of Gem3(ΔN)-mediated interference. Interestingly, phenotypes induced by human SMN overexpression in Drosophila exhibit similarities to those induced by overexpression of Gem3(ΔN). Through enhanced knockdown we also uncover a requirement of Gemin2, Gemin3 and Gemin5 for viability and motor behaviour, including locomotion as well as flight, in muscle. Notably, in the case of Gemin3 and Gemin5, such function also depends on adequate levels of the respective protein in neurons. Overall, these findings lead us to speculate that absence of any one member is sufficient to arrest the SMN-Gemins complex function in a nucleocentric pathway, which is critical for motor function in vivo.
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Yamanaka N, Rewitz KF, O’Connor MB. Ecdysone control of developmental transitions: lessons from Drosophila research. ANNUAL REVIEW OF ENTOMOLOGY 2013; 58:497-516. [PMID: 23072462 PMCID: PMC4060523 DOI: 10.1146/annurev-ento-120811-153608] [Citation(s) in RCA: 457] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The steroid hormone ecdysone is the central regulator of insect developmental transitions. Recent new advances in our understanding of ecdysone action have relied heavily on the application of Drosophila melanogaster molecular genetic tools to study insect metamorphosis. In this review, we focus on three major aspects of Drosophila ecdysone biology: (a) factors that regulate the timing of ecdysone release, (b) molecular basis of stage- and tissue-specific responses to ecdysone, and (c) feedback regulation and coordination of ecdysone signaling.
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Affiliation(s)
- Naoki Yamanaka
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
| | - Kim F. Rewitz
- Department of Science, Systems and Models, Roskilde University, 4000 Roskilde, Denmark
| | - Michael B. O’Connor
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
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Carbonell A, Mazo A, Serras F, Corominas M. Ash2 acts as an ecdysone receptor coactivator by stabilizing the histone methyltransferase Trr. Mol Biol Cell 2012. [PMID: 23197473 PMCID: PMC3565548 DOI: 10.1091/mbc.e12-04-0267] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The molting hormone ecdysone triggers chromatin changes via histone modifications that are important for gene regulation. On hormone activation, the ecdysone receptor (EcR) binds to the SET domain-containing histone H3 methyltransferase trithorax-related protein (Trr). Methylation of histone H3 at lysine 4 (H3K4me), which is associated with transcriptional activation, requires several cofactors, including Ash2. We find that ash2 mutants have severe defects in pupariation and metamorphosis due to a lack of activation of ecdysone-responsive genes. This transcriptional defect is caused by the absence of the H3K4me3 marks set by Trr in these genes. We present evidence that Ash2 interacts with Trr and is required for its stabilization. Thus we propose that Ash2 functions together with Trr as an ecdysone receptor coactivator.
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Affiliation(s)
- Albert Carbonell
- Departament de Genètica and Institut de Biomedicina, Universitat de Barcelona, 08028 Barcelona, Spain
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Cryptocephal, the Drosophila melanogaster ATF4, is a specific coactivator for ecdysone receptor isoform B2. PLoS Genet 2012; 8:e1002883. [PMID: 22912598 PMCID: PMC3415445 DOI: 10.1371/journal.pgen.1002883] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 06/22/2012] [Indexed: 01/02/2023] Open
Abstract
The ecdysone receptor is a heterodimer of two nuclear receptors, the Ecdysone receptor (EcR) and Ultraspiracle (USP). In Drosophila melanogaster, three EcR isoforms share common DNA and ligand-binding domains, but these proteins differ in their most N-terminal regions and, consequently, in the activation domains (AF1s) contained therein. The transcriptional coactivators for these domains, which impart unique transcriptional regulatory properties to the EcR isoforms, are unknown. Activating transcription factor 4 (ATF4) is a basic-leucine zipper transcription factor that plays a central role in the stress response of mammals. Here we show that Cryptocephal (CRC), the Drosophila homolog of ATF4, is an ecdysone receptor coactivator that is specific for isoform B2. CRC interacts with EcR-B2 to promote ecdysone-dependent expression of ecdysis-triggering hormone (ETH), an essential regulator of insect molting behavior. We propose that this interaction explains some of the differences in transcriptional properties that are displayed by the EcR isoforms, and similar interactions may underlie the differential activities of other nuclear receptors with distinct AF1-coactivators. Nuclear receptors are proteins that regulate gene expression in response to steroid and thyroid hormones and other small lipid-soluble signaling molecules. In many cases, nuclear receptor genes encode multiple variants (isoforms) that direct tissue- and stage-specific hormonal responses. The sequence differences among isoforms are often found at the protein N-terminus, which mediates hormone-independent interactions with unknown regulatory partners to control target gene expression. Here, we show that the fruit fly Cryptocephal (CRC) protein is a specific coactivator for one of three isoforms of the receptor for the insect molting steroid, ecdysone. Our findings reveal a mechanism for differential activation of gene expression in response to ecdysone during insect molting and metamorphosis, and contribute to our understanding of isoform-specific functions of nuclear hormone receptors.
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Buckingham M, Liu JL. U bodies respond to nutrient stress in Drosophila. Exp Cell Res 2011; 317:2835-44. [DOI: 10.1016/j.yexcr.2011.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 09/01/2011] [Accepted: 09/04/2011] [Indexed: 10/17/2022]
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Grice SJ, Sleigh JN, Liu JL, Sattelle DB. Invertebrate models of spinal muscular atrophy: insights into mechanisms and potential therapeutics. Bioessays 2011; 33:956-65. [PMID: 22009672 DOI: 10.1002/bies.201100082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Invertebrate genetic models with their tractable neuromuscular systems are effective vehicles for the study of human nerve and muscle disorders. This is exemplified by insights made into spinal muscular atrophy (SMA) using the fruit fly Drosophila melanogaster and the nematode worm Caenorhabditis elegans. For speed and economy, these invertebrates offer convenient, whole-organism platforms for genetic screening as well as RNA interference (RNAi) and chemical library screens, permitting the rapid testing of hypotheses related to disease mechanisms and the exploration of new therapeutic routes and drug candidates. Here, we discuss recent developments encompassing synaptic physiology, RNA processing, and screening of compound and genome-scale RNAi libraries, showcasing the importance of invertebrate SMA models.
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Affiliation(s)
- Stuart J Grice
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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Grice SJ, Liu JL. Survival motor neuron protein regulates stem cell division, proliferation, and differentiation in Drosophila. PLoS Genet 2011; 7:e1002030. [PMID: 21490958 PMCID: PMC3072375 DOI: 10.1371/journal.pgen.1002030] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 02/04/2011] [Indexed: 12/04/2022] Open
Abstract
Spinal muscular atrophy is a severe neurogenic disease that is caused by mutations in the human survival motor neuron 1 (SMN1) gene. SMN protein is required for the assembly of small nuclear ribonucleoproteins and a dramatic reduction of the protein leads to cell death. It is currently unknown how the reduction of this ubiquitously essential protein can lead to tissue-specific abnormalities. In addition, it is still not known whether the disease is caused by developmental or degenerative defects. Using the Drosophila system, we show that SMN is enriched in postembryonic neuroblasts and forms a concentration gradient in the differentiating progeny. In addition to the developing Drosophila larval CNS, Drosophila larval and adult testes have a striking SMN gradient. When SMN is reduced in postembryonic neuroblasts using MARCM clonal analysis, cell proliferation and clone formation defects occur. These SMN mutant neuroblasts fail to correctly localise Miranda and have reduced levels of snRNAs. When SMN is removed, germline stem cells are lost more frequently. We also show that changes in SMN levels can disrupt the correct timing of cell differentiation. We conclude that highly regulated SMN levels are essential to drive timely cell proliferation and cell differentiation.
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Affiliation(s)
- Stuart J. Grice
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Ji-Long Liu
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
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König A, Yatsenko AS, Weiss M, Shcherbata HR. Ecdysteroids affect Drosophila ovarian stem cell niche formation and early germline differentiation. EMBO J 2011; 30:1549-62. [PMID: 21423150 PMCID: PMC3102283 DOI: 10.1038/emboj.2011.73] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 02/22/2011] [Indexed: 01/13/2023] Open
Abstract
Previously, it has been shown that in Drosophila steroid hormones are required for progression of oogenesis during late stages of egg maturation. Here, we show that ecdysteroids regulate progression through the early steps of germ cell lineage. Upon ecdysone signalling deficit germline stem cell progeny delay to switch on a differentiation programme. This differentiation impediment is associated with reduced TGF-β signalling in the germline and increased levels of cell adhesion complexes and cytoskeletal proteins in somatic escort cells. A co-activator of the ecdysone receptor, Taiman is the spatially restricted regulator of the ecdysone signalling pathway in soma. Additionally, when ecdysone signalling is perturbed during the process of somatic stem cell niche establishment enlarged functional niches able to host additional stem cells are formed.
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Affiliation(s)
- Annekatrin König
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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dDOR is an EcR coactivator that forms a feed-forward loop connecting insulin and ecdysone signaling. Curr Biol 2010; 20:1799-808. [PMID: 20888228 DOI: 10.1016/j.cub.2010.08.055] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 07/30/2010] [Accepted: 08/25/2010] [Indexed: 01/09/2023]
Abstract
BACKGROUND Mammalian DOR was discovered as a gene whose expression is misregulated in muscle of Zucker diabetic rats. Because no DOR loss-of-function mammalian models are available, we analyze here the in vivo function of DOR by studying flies mutant for Drosophila DOR (dDOR). RESULTS We show that dDOR is a novel coactivator of ecdysone receptor (EcR) that is needed during metamorphosis. dDOR binds EcR and is required for maximal EcR transcriptional activity. In the absence of dDOR, flies display a number of ecdysone loss-of-function phenotypes such as impaired spiracle eversion, impaired salivary gland degradation, and pupal lethality. Furthermore, dDOR knockout flies are lean. We find that dDOR expression is inhibited by insulin signaling via FOXO. CONCLUSION This work uncovers dDOR as a novel EcR coactivator. It also establishes a mutual antagonistic relationship between ecdysone and insulin signaling in the fly fat body. Furthermore, because ecdysone signaling inhibits insulin signaling in the fat body, this also uncovers a feed-forward mechanism whereby ecdysone potentiates its own signaling via dDOR.
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Cauchi RJ, Sanchez-Pulido L, Liu JL. Drosophila SMN complex proteins Gemin2, Gemin3, and Gemin5 are components of U bodies. Exp Cell Res 2010; 316:2354-64. [PMID: 20452345 DOI: 10.1016/j.yexcr.2010.05.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 03/25/2010] [Accepted: 05/03/2010] [Indexed: 11/26/2022]
Abstract
Uridine-rich small nuclear ribonucleoproteins (U snRNPs) play key roles in pre-mRNA processing in the nucleus. The assembly of most U snRNPs takes place in the cytoplasm and is facilitated by the survival motor neuron (SMN) complex. Discrete cytoplasmic RNA granules called U bodies have been proposed to be specific sites for snRNP assembly because they contain U snRNPs and SMN. U bodies invariably associate with P bodies, which are involved in mRNA decay and translational control. However, it remains unknown whether other SMN complex proteins also localise to U bodies. In Drosophila there are four SMN complex proteins, namely SMN, Gemin2/CG10419, Gemin3 and Gemin5/Rigor mortis. Drosophila Gemin3 was originally identified as the Drosophila orthologue of human and yeast Dhh1, a component of P bodies. Through an in silico analysis of the DEAD-box RNA helicases we confirmed that Gemin3 is the bona fide Drosophila orthologue of vertebrate Gemin3 whereas the Drosophila orthologue of Dhh1 is Me31B. We then made use of the Drosophila egg chamber as a model system to study the subcellular distribution of the Gemin proteins as well as Me31B. Our cytological investigations show that Gemin2, Gemin3 and Gemin5 colocalise with SMN in U bodies. Although they are excluded from P bodies, as components of U bodies, Gemin2, Gemin3 and Gemin5 are consistently found associated with P bodies, wherein Me31B resides. In addition to a role in snRNP biogenesis, SMN complexes residing in U bodies may also be involved in mRNP assembly and/or transport.
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Affiliation(s)
- Ruben J Cauchi
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
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Birkholz DA, Chou WH, Phistry MM, Britt SG. Disruption of photoreceptor cell patterning in the Drosophila Scutoid mutant. Fly (Austin) 2009; 3:253-62. [PMID: 19949290 DOI: 10.4161/fly.10546] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cell fate determination in many systems is based upon inductive events driven by cell-cell interactions. Inductive signaling regulates many aspects of Drosophila compound eye development. Accumulating evidence suggests that the color sensitivity of the R8 photoreceptor cell within an individual ommatidium is regulated by an inductive signal from the adjacent R7 photoreceptor cell. This signal is thought to control an induced versus default cell-fate switch that coordinates the visual pigment expression and color sensitivities of adjacent R7 and R8 photoreceptor cells. Here we describe a disruption in R7 and R8 cell patterning in Scutoid mutants that is due to inappropriate signals from Rh4-expressing R7 cells inducing Rh5 expression in adjacent R8 cells. This dominant phenotype results from the misexpression of the transcriptional repressor snail, which with the co-repressor C-terminal-Binding-Protein represses rhomboid expression in the developing eye. We show that loss of rhomboid suppresses the Scutoid phenotype. However in contrast to the loss of rhomboid alone, which entirely blocks the normal inductive signal from the R7 to the R8 photoreceptor cell, Scutoid rhomboid double mutants display normal Rh5 and Rh6 expression. Our detailed analysis of this unusual dominant gain-of-function neomorphic phenotype suggests that the induction of Rh5 expression in Scutoid mutants is partially rhomboid independent.
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Affiliation(s)
- Denise A Birkholz
- Department of Cell and Developmental Biology, University of Colorado Denver, School of Medicine, Aurora, CO, USA
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Abstract
The molting process in arthropods is regulated by steroid hormones acting via nuclear receptor proteins. The most common molting hormone is the ecdysteroid, 20-hydroxyecdysone. The receptors of 20-hydroxyecdysone have also been identified in many arthropod species, and the amino acid sequences determined. The functional molting hormone receptors consist of two members of the nuclear receptor superfamily, namely the ecdysone receptor and the ultraspiracle, although the ecdysone receptor may be functional, in some instances, without the ultraspiracle. Generally, the ecdysone receptor/ultraspiracle heterodimer binds to a number of ecdysone response elements, sequence motifs that reside in the promoter of various ecdysteroid-responsive genes. In the ensuing transcriptional induction, the ecdysone receptor/ultraspiracle complex binds to 20-hydroxyecdysone or to a cognate ligand that, in turn, leads to the release of a corepressor and the recruitment of coactivators. 3D structures of the ligand-binding domains of the ecdysone receptor and the ultraspiracle have been solved for a few insect species. Ecdysone agonists bind to ecdysone receptors specifically, and ligand-ecdysone receptor binding is enhanced in the presence of the ultraspiracle in insects. The basic mode of ecdysteroid receptor action is highly conserved, but substantial functional differences exist among the receptors of individual species. Even though the transcriptional effects are apparently similar for ecdysteroids and nonsteroidal compounds such as diacylhydrazines, the binding shapes are different between them. The compounds having the strongest binding affinity to receptors ordinarily have strong molting hormone activity. The ability of the ecdysone receptor/ultraspiracle complex to manifest the effects of small lipophilic agonists has led to their use as gene switches for medical and agricultural applications.
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Affiliation(s)
- Yoshiaki Nakagawa
- Division of Applied Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-Ku, Kyoto 606-8502, Japan.
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Inositol 1,4,5- trisphosphate receptor function in Drosophila insulin producing cells. PLoS One 2009; 4:e6652. [PMID: 19680544 PMCID: PMC2721413 DOI: 10.1371/journal.pone.0006652] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 07/13/2009] [Indexed: 01/26/2023] Open
Abstract
The Inositol 1,4,5- trisphosphate receptor (InsP3R) is an intracellular ligand gated channel that releases calcium from intracellular stores in response to extracellular signals. To identify and understand physiological processes and behavior that depends on the InsP3 signaling pathway at a systemic level, we are studying Drosophila mutants for the InsP3R (itpr) gene. Here, we show that growth defects precede larval lethality and both are a consequence of the inability to feed normally. Moreover, restoring InsP3R function in insulin producing cells (IPCs) in the larval brain rescues the feeding deficit, growth and lethality in the itpr mutants to a significant extent. We have previously demonstrated a critical requirement for InsP3R activity in neuronal cells, specifically in aminergic interneurons, for larval viability. Processes from the IPCs and aminergic domain are closely apposed in the third instar larval brain with no visible cellular overlap. Ubiquitous depletion of itpr by dsRNA results in feeding deficits leading to larval lethality similar to the itpr mutant phenotype. However, when itpr is depleted specifically in IPCs or aminergic neurons, the larvae are viable. These data support a model where InsP3R activity in non-overlapping neuronal domains independently rescues larval itpr phenotypes by non-cell autonomous mechanisms.
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Beck Y, Delaporte C, Moras D, Richards G, Billas IM. The ligand-binding domains of the three RXR-USP nuclear receptor types support distinct tissue and ligand specific hormonal responses in transgenic Drosophila. Dev Biol 2009; 330:1-11. [DOI: 10.1016/j.ydbio.2008.12.042] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 11/18/2008] [Accepted: 12/22/2008] [Indexed: 11/16/2022]
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Jetten AM. Retinoid-related orphan receptors (RORs): critical roles in development, immunity, circadian rhythm, and cellular metabolism. NUCLEAR RECEPTOR SIGNALING 2009; 7:e003. [PMID: 19381306 PMCID: PMC2670432 DOI: 10.1621/nrs.07003] [Citation(s) in RCA: 530] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 03/18/2009] [Indexed: 12/11/2022]
Abstract
The last few years have witnessed a rapid increase in our knowledge of the retinoid-related orphan receptors RORalpha, -beta, and -gamma (NR1F1-3), their mechanism of action, physiological functions, and their potential role in several pathologies. The characterization of ROR-deficient mice and gene expression profiling in particular have provided great insights into the critical functions of RORs in the regulation of a variety of physiological processes. These studies revealed that RORalpha plays a critical role in the development of the cerebellum, that both RORalpha and RORbeta are required for the maturation of photoreceptors in the retina, and that RORgamma is essential for the development of several secondary lymphoid tissues, including lymph nodes. RORs have been further implicated in the regulation of various metabolic pathways, energy homeostasis, and thymopoiesis. Recent studies identified a critical role for RORgamma in lineage specification of uncommitted CD4+ T helper cells into Th17 cells. In addition, RORs regulate the expression of several components of the circadian clock and may play a role in integrating the circadian clock and the rhythmic pattern of expression of downstream (metabolic) genes. Study of ROR target genes has provided insights into the mechanisms by which RORs control these processes. Moreover, several reports have presented evidence for a potential role of RORs in several pathologies, including osteoporosis, several autoimmune diseases, asthma, cancer, and obesity, and raised the possibility that RORs may serve as potential targets for chemotherapeutic intervention. This prospect was strengthened by recent evidence showing that RORs can function as ligand-dependent transcription factors.
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MESH Headings
- Animals
- Circadian Rhythm/genetics
- Circadian Rhythm/physiology
- Growth/physiology
- Humans
- Immune System/physiology
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Nuclear Receptor Subfamily 1, Group F, Member 2
- Nuclear Receptor Subfamily 1, Group F, Member 3
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/physiology
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/physiology
- Trans-Activators/genetics
- Trans-Activators/physiology
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Affiliation(s)
- Anton M Jetten
- Cell Biology Section, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA.
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Shpargel KB, Praveen K, Rajendra TK, Matera AG. Gemin3 is an essential gene required for larval motor function and pupation in Drosophila. Mol Biol Cell 2008; 20:90-101. [PMID: 18923150 DOI: 10.1091/mbc.e08-01-0024] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The assembly of metazoan Sm-class small nuclear ribonucleoproteins (snRNPs) is an elaborate, step-wise process that takes place in multiple subcellular compartments. The initial steps, including formation of the core RNP, are mediated by the survival motor neuron (SMN) protein complex. Loss-of-function mutations in human SMN1 result in a neuromuscular disease called spinal muscular atrophy. The SMN complex is comprised of SMN and a number of tightly associated proteins, collectively called Gemins. In this report, we identify and characterize the fruitfly ortholog of the DEAD box protein, Gemin3. Drosophila Gemin3 (dGem3) colocalizes and interacts with dSMN in vitro and in vivo. RNA interference for dGem3 codepletes dSMN and inhibits efficient Sm core assembly in vitro. Transposon insertion mutations in Gemin3 are larval lethals and also codeplete dSMN. Transgenic overexpression of dGem3 rescues lethality, but overexpression of dSMN does not, indicating that loss of dSMN is not the primary cause of death. Gemin3 mutant larvae exhibit motor defects similar to previously characterized Smn alleles. Remarkably, appreciable numbers of Gemin3 mutants (along with one previously undescribed Smn allele) survive as larvae for several weeks without pupating. Our results demonstrate the conservation of Gemin3 protein function in metazoan snRNP assembly and reveal that loss of either Smn or Gemin3 can contribute to neuromuscular dysfunction.
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Affiliation(s)
- Karl B Shpargel
- Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4955, USA
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Evolution of an RNP assembly system: a minimal SMN complex facilitates formation of UsnRNPs in Drosophila melanogaster. Proc Natl Acad Sci U S A 2008; 105:10045-50. [PMID: 18621711 DOI: 10.1073/pnas.0802287105] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In vertebrates, assembly of spliceosomal uridine-rich small nuclear ribonucleoproteins (UsnRNPs) is mediated by the SMN complex, a macromolecular entity composed of the proteins SMN and Gemins 2-8. Here we have studied the evolution of this machinery using complete genome assemblies of multiple model organisms. The SMN complex has gained complexity in evolution by a blockwise addition of Gemins onto an ancestral core complex composed of SMN and Gemin2. In contrast to this overall evolutionary trend to more complexity in metazoans, orthologs of most Gemins are missing in dipterans. In accordance with these bioinformatic data a previously undescribed biochemical purification strategy elucidated that the dipteran Drosophila melanogaster contains an SMN complex of remarkable simplicity. Surprisingly, this minimal complex not only mediates the assembly reaction in a manner very similar to its vertebrate counterpart, but also prevents misassembly onto nontarget RNAs. Our data suggest that only a minority of Gemins are required for the assembly reaction per se, whereas others may serve additional functions in the context of UsnRNP biogenesis. The evolution of the SMN complex is an interesting example of how the simplification of a biochemical process contributes to genome compaction.
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Chen J, Wang H, Wang YF. Overexpression of HmgD causes the failure of pupariation in Drosophila by affecting ecdysone receptor pathway. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2008; 68:123-133. [PMID: 18330897 DOI: 10.1002/arch.20237] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
HmgD encodes Drosophila homologue of high mobility group proteins (HMGD), which are thought to have an architectural function in chromatin organization. However, current opinions about the function of HMGD in Drosophila development are controversial. Our previous studies have shown that ubiquitous overexpression of HmgD caused the formation of melanotic tumors in the Drosophila larvae by prematurely activating the Ras-MAPK pathway. Here we report that under maternal control, the viability of flies links with overexpression of HmgD, while under ubiquitous control, ActGal4, overexpressing HmgD animals, which display prolonged larval stages around day 13, developmentally stagnate in the larva-white pupa transition. Ecdysone feeding did not rescue overexpressing HmgD animals. RT-PCR analyses show that overexpression of HmgD does not affect the temporal expression pattern of ecdysone receptor gene EcR, whereas transcriptional patterns of some key regulatory genes, such as E74A, E74B, E75A, E75B, betaFTZ-F1, are changed greatly. These results suggest that ubiquitous overexpression of HmgD results in the failure of pupariation neither by affecting the process of ecdysone synthesis and release nor by abnormal EcR transcription, but by causing expression of EcR regulatory nuclear receptors out of schedule. The results led us to postulate that overexpression of HMGD likely changes the signaling cascade of Drosophila metamorphosis by an interaction between HMGD and DNA strands, and subsequently by an error of DNA binding abilities and transcriptional activities of some nuclear receptor genes. Arch. Insect Biochem. Physiol. 2008.
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Affiliation(s)
- Jing Chen
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, PR China
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49
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Stabell M, Larsson J, Aalen RB, Lambertsson A. Drosophila dSet2 functions in H3-K36 methylation and is required for development. Biochem Biophys Res Commun 2007; 359:784-789. [PMID: 17560546 DOI: 10.1016/j.bbrc.2007.05.189] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2007] [Accepted: 05/28/2007] [Indexed: 11/28/2022]
Abstract
Lysine methylation has important functions in biological processes that range from heterochromatin formation to transcription regulation. Here, we demonstrate that Drosophila dSet2 encodes a developmentally essential histone H3 lysine 36 (K36) methyltransferase. Larvae subjected to RNA interference-mediated (RNAi) suppression of dSet2 lack dSet2 expression and H3-K36 methylation, indicating that dSet2 is the sole enzyme responsible for this modification in Drosophila melanogaster. dSet2 RNAi blocks puparium formation and adult development, and causes partial (blister) separation of the dorsal and ventral wing epithelia, defects suggesting a failure of the ecdysone-controlled genetic program. A transheterozygous EcR null mutation/dSet2 RNAi combination produces a complete (balloon) separation of the wing surfaces, revealing a genetic interaction between EcR and dSet2. Using immunoprecipitation, we demonstrate that dSet2 associates with the hyperphosphorylated form of RNA polymerase II (RNAPII).
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Affiliation(s)
- Marianne Stabell
- Institute of Molecular Biosciences, University of Oslo, PO Box 1041 Blindern, NO-0316 Oslo, Norway
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Zhu J, Chen L, Sun G, Raikhel AS. The competence factor beta Ftz-F1 potentiates ecdysone receptor activity via recruiting a p160/SRC coactivator. Mol Cell Biol 2006; 26:9402-12. [PMID: 17015464 PMCID: PMC1698532 DOI: 10.1128/mcb.01318-06] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 08/22/2006] [Accepted: 09/21/2006] [Indexed: 11/20/2022] Open
Abstract
Hormones provide generalized signals that are interpreted in a specific spatial and temporal manner by a developing or reproducing multicellular organism. The ability to respond to hormones is determined by the competence of a cell or a tissue. The betaFtz-F1 orphan nuclear receptor acts as a competence factor for the steroid hormone 20-hydroxyecdysone (20E) in Drosophila melanogaster metamorphosis and mosquito reproduction. The molecular nature of the betaFtz-F1 action remains unclear. We report that the protein-protein interaction between betaFtz-F1 and a p160/SRC coactivator of the ecdysone receptor, FISC, is crucial for the stage-specific expression of the 20E effector genes during mosquito reproduction. This interaction dramatically increases recruitment of FISC to the functional ecdysone receptor in a 20E-dependent manner. The presence of betaFtz-F1 facilitates loading of FISC and the ecdysone receptor on the target promoters, leading to enhanced local histone H4 acetylation and robust activation of the target genes. Thus, our results reveal the molecular basis of competence for the stage-specific 20E response.
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Affiliation(s)
- Jinsong Zhu
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
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