1
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Zhukova M, Schedl P, Shidlovskii YV. The role of secondary structures in the functioning of 3' untranslated regions of mRNA: A review of functions of 3' UTRs' secondary structures and hypothetical involvement of secondary structures in cytoplasmic polyadenylation in Drosophila. Bioessays 2024; 46:e2300099. [PMID: 38161240 DOI: 10.1002/bies.202300099] [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: 06/07/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 01/03/2024]
Abstract
3' untranslated regions (3' UTRs) of mRNAs have many functions, including mRNA processing and transport, translational regulation, and mRNA degradation and stability. These different functions require cis-elements in 3' UTRs that can be either sequence motifs or RNA structures. Here we review the role of secondary structures in the functioning of 3' UTRs and discuss some of the trans-acting factors that interact with these secondary structures in eukaryotic organisms. We propose potential participation of 3'-UTR secondary structures in cytoplasmic polyadenylation in the model organism Drosophila melanogaster. Because the secondary structures of 3' UTRs are essential for post-transcriptional regulation of gene expression, their disruption leads to a wide range of disorders, including cancer and cardiovascular diseases. Trans-acting factors, such as STAU1 and nucleolin, which interact with 3'-UTR secondary structures of target transcripts, influence the pathogenesis of neurodegenerative diseases and tumor metastasis, suggesting that they are possible therapeutic targets.
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Affiliation(s)
- Mariya Zhukova
- Laboratory of Gene Expression Regulation in Development, Russian Academy of Sciences, Institute of Gene Biology, Moscow, Russia
| | - Paul Schedl
- Laboratory of Gene Expression Regulation in Development, Russian Academy of Sciences, Institute of Gene Biology, Moscow, Russia
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Yulii V Shidlovskii
- Laboratory of Gene Expression Regulation in Development, Russian Academy of Sciences, Institute of Gene Biology, Moscow, Russia
- Department of Biology and General Genetics, Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
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2
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Sarnowski CP, Bikaki M, Leitner A. Cross-linking and mass spectrometry as a tool for studying the structural biology of ribonucleoproteins. Structure 2022; 30:441-461. [PMID: 35366400 DOI: 10.1016/j.str.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 02/03/2022] [Accepted: 03/01/2022] [Indexed: 11/17/2022]
Abstract
Cross-linking and mass spectrometry (XL-MS) workflows represent an increasingly popular technique for low-resolution structural studies of macromolecular complexes. Cross-linking reactions take place in the solution state, capturing contact sites between components of a complex that represent the native, functionally relevant structure. Protein-protein XL-MS protocols are widely adopted, providing precise localization of cross-linking sites to single amino acid positions within a pair of cross-linked peptides. In contrast, protein-RNA XL-MS workflows are evolving rapidly and differ in their ability to localize interaction regions within the RNA sequence. Here, we review protein-protein and protein-RNA XL-MS workflows, and discuss their applications in studies of protein-RNA complexes. The examples highlight the complementary value of XL-MS in structural studies of protein-RNA complexes, where more established high-resolution techniques might be unable to produce conclusive data.
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Affiliation(s)
- Chris P Sarnowski
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zurich, Switzerland; Systems Biology PhD Program, University of Zürich and ETH Zürich, Zurich, Switzerland
| | - Maria Bikaki
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zurich, Switzerland
| | - Alexander Leitner
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zurich, Switzerland.
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3
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Cai X, Rondeel I, Baumgartner S. Modulating the bicoid gradient in space and time. Hereditas 2021; 158:29. [PMID: 34404481 PMCID: PMC8371787 DOI: 10.1186/s41065-021-00192-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/19/2021] [Indexed: 11/15/2022] Open
Abstract
Background The formation of the Bicoid (Bcd) gradient in the early Drosophila is one of the most fascinating observations in biology and serves as a paradigm for gradient formation, yet its mechanism is still not fully understood. Two distinct models were proposed in the past, the SDD and the ARTS model. Results We define novel cis- and trans-acting factors that are indispensable for gradient formation. The first one is the poly A tail length of the bcd mRNA where we demonstrate that it changes not only in time, but also in space. We show that posterior bcd mRNAs possess a longer poly tail than anterior ones and this elongation is likely mediated by wispy (wisp), a poly A polymerase. Consequently, modulating the activity of Wisp results in changes of the Bcd gradient, in controlling downstream targets such as the gap and pair-rule genes, and also in influencing the cuticular pattern. Attempts to modulate the Bcd gradient by subjecting the egg to an extra nuclear cycle, i.e. a 15th nuclear cycle by means of the maternal haploid (mh) mutation showed no effect, neither on the appearance of the gradient nor on the control of downstream target. This suggests that the segmental anlagen are determined during the first 14 nuclear cycles. Finally, we identify the Cyclin B (CycB) gene as a trans-acting factor that modulates the movement of Bcd such that Bcd movement is allowed to move through the interior of the egg. Conclusions Our analysis demonstrates that Bcd gradient formation is far more complex than previously thought requiring a revision of the models of how the gradient is formed.
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Affiliation(s)
- Xiaoli Cai
- Departmentof Experimental Medical Sciences, Lund University, BMC D10, 22184, Lund, Sweden
| | - Inge Rondeel
- Departmentof Experimental Medical Sciences, Lund University, BMC D10, 22184, Lund, Sweden.,Present address: Hubrecht Institute, 3584 CT, Utrecht, The Netherlands
| | - Stefan Baumgartner
- Departmentof Experimental Medical Sciences, Lund University, BMC D10, 22184, Lund, Sweden. .,Department of Biology, University of Konstanz, 78457, Konstanz, Germany.
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4
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Ballou ER, Cook AG, Wallace EWJ. Repeated Evolution of Inactive Pseudonucleases in a Fungal Branch of the Dis3/RNase II Family of Nucleases. Mol Biol Evol 2021; 38:1837-1846. [PMID: 33313834 PMCID: PMC8097288 DOI: 10.1093/molbev/msaa324] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The RNase II family of 3'-5' exoribonucleases is present in all domains of life, and eukaryotic family members Dis3 and Dis3L2 play essential roles in RNA degradation. Ascomycete yeasts contain both Dis3 and inactive RNase II-like "pseudonucleases." The latter function as RNA-binding proteins that affect cell growth, cytokinesis, and fungal pathogenicity. However, the evolutionary origins of these pseudonucleases are unknown: What sequence of events led to their novel function, and when did these events occur? Here, we show how RNase II pseudonuclease homologs, including Saccharomyces cerevisiae Ssd1, are descended from active Dis3L2 enzymes. During fungal evolution, active site mutations in Dis3L2 homologs have arisen at least four times, in some cases following gene duplication. In contrast, N-terminal cold-shock domains and regulatory features are conserved across diverse dikarya and mucoromycota, suggesting that the nonnuclease function requires these regions. In the basidiomycete pathogenic yeast Cryptococcus neoformans, the single Ssd1/Dis3L2 homolog is required for cytokinesis from polyploid "titan" growth stages. This phenotype of C. neoformans Ssd1/Dis3L2 deletion is consistent with those of inactive fungal pseudonucleases, yet the protein retains an active site sequence signature. We propose that a nuclease-independent function for Dis3L2 arose in an ancestral hyphae-forming fungus. This second function has been conserved across hundreds of millions of years, whereas the RNase activity was lost repeatedly in independent lineages.
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Affiliation(s)
- Elizabeth R Ballou
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Atlanta G Cook
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Edward W J Wallace
- Institute for Cell Biology and SynthSys, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
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5
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Goldman CH, Neiswender H, Baker F, Veeranan-Karmegam R, Misra S, Gonsalvez GB. Optimal RNA binding by Egalitarian, a Dynein cargo adaptor, is critical for maintaining oocyte fate in Drosophila. RNA Biol 2021; 18:2376-2389. [PMID: 33904382 DOI: 10.1080/15476286.2021.1914422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The Dynein motor is responsible for the localization of numerous mRNAs within Drosophila oocytes and embryos. The RNA binding protein, Egalitarian (Egl), is thought to link these various RNA cargoes with Dynein. Although numerous studies have shown that Egl is able to specifically associate with these RNAs, the nature of these interactions has remained elusive. Egl contains a central RNA binding domain that shares limited homology with an exonuclease, yet Egl binds to RNA without degrading it. Mutations have been identified within Egl that disrupt its association with its protein interaction partners, BicaudalD (BicD) and Dynein light chain (Dlc), but no mutants have been described that are specifically defective for RNA binding. In this report, we identified a series of positively charged residues within Egl that are required for RNA binding. Using corresponding RNA binding mutants, we demonstrate that specific RNA cargoes are more reliant on maximal Egl RNA biding activity for their correct localization in comparison to others. We also demonstrate that specification and maintenance of oocyte fate requires maximal Egl RNA binding activity. Even a subtle reduction in Egl's RNA binding activity completely disrupts this process. Our results show that efficient RNA localization at the earliest stages of oogenesis is required for specification of the oocyte and restriction of meiosis to a single cell.
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Affiliation(s)
- Chandler H Goldman
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA.,Department of Genetics, Davidson Life Sciences Complex, University of Georgia, Athens, GA, USA
| | - Hannah Neiswender
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Frederick Baker
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | | | - Saurav Misra
- Dept. Of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS,USA
| | - Graydon B Gonsalvez
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
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6
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Xie W, Sowemimo I, Hayashi R, Wang J, Burkard TR, Brennecke J, Ameres SL, Patel DJ. Structure-function analysis of microRNA 3'-end trimming by Nibbler. Proc Natl Acad Sci U S A 2020; 117:30370-30379. [PMID: 33199607 PMCID: PMC7720153 DOI: 10.1073/pnas.2018156117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Nibbler (Nbr) is a 3'-to-5' exoribonuclease whose catalytic 3'-end trimming activity impacts microRNA (miRNA) and PIWI-interacting RNA (piRNA) biogenesis. Here, we report on structural and functional studies to decipher the contributions of Nbr's N-terminal domain (NTD) and exonucleolytic domain (EXO) in miRNA 3'-end trimming. We have solved the crystal structures of the NTD core and EXO domains of Nbr, both in the apo-state. The NTD-core domain of Aedes aegypti Nbr adopts a HEAT-like repeat scaffold with basic patches constituting an RNA-binding surface exhibiting a preference for binding double-strand RNA (dsRNA) over single-strand RNA (ssRNA). Structure-guided functional assays in Drosophila S2 cells confirmed a principal role of the NTD in exonucleolytic miRNA trimming, which depends on basic surface patches. Gain-of-function experiments revealed a potential role of the NTD in recruiting Nbr to Argonaute-bound small RNA substrates. The EXO domain of A. aegypti and Drosophila melanogaster Nbr adopt a mixed α/β-scaffold with a deep pocket lined by a DEDDy catalytic cleavage motif. We demonstrate that Nbr's EXO domain exhibits Mn2+-dependent ssRNA-specific 3'-to-5' exoribonuclease activity. Modeling of a 3' terminal Uridine into the catalytic pocket of Nbr EXO indicates that 2'-O-methylation of the 3'-U would result in a steric clash with a tryptophan side chain, suggesting that 2'-O-methylation protects small RNAs from Nbr-mediated trimming. Overall, our data establish that Nbr requires its NTD as a substrate recruitment platform to execute exonucleolytic miRNA maturation, catalyzed by the ribonuclease EXO domain.
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Affiliation(s)
- Wei Xie
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065
| | - Ivica Sowemimo
- Institute of Molecular Biotechnology, Vienna BioCenter, 1030 Vienna, Austria
| | - Rippei Hayashi
- Department of Genome Sciences, The John Curtin School of Medical Research, Australian National University, Canberra 2601, Australia
| | - Juncheng Wang
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065
| | - Thomas R Burkard
- Institute of Molecular Biotechnology, Vienna BioCenter, 1030 Vienna, Austria
| | - Julius Brennecke
- Institute of Molecular Biotechnology, Vienna BioCenter, 1030 Vienna, Austria;
| | - Stefan L Ameres
- Institute of Molecular Biotechnology, Vienna BioCenter, 1030 Vienna, Austria;
- Max Perutz Labs, University of Vienna, Vienna BioCenter, 1030 Vienna, Austria
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065;
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7
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Tauber D, Tauber G, Parker R. Mechanisms and Regulation of RNA Condensation in RNP Granule Formation. Trends Biochem Sci 2020; 45:764-778. [PMID: 32475683 PMCID: PMC7211619 DOI: 10.1016/j.tibs.2020.05.002] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/20/2020] [Accepted: 05/05/2020] [Indexed: 01/01/2023]
Abstract
Ribonucleoprotein (RNP) granules are RNA-protein assemblies that are involved in multiple aspects of RNA metabolism and are linked to memory, development, and disease. Some RNP granules form, in part, through the formation of intermolecular RNA-RNA interactions. In vitro, such trans RNA condensation occurs readily, suggesting that cells require mechanisms to modulate RNA-based condensation. We assess the mechanisms of RNA condensation and how cells modulate this phenomenon. We propose that cells control RNA condensation through ATP-dependent processes, static RNA buffering, and dynamic post-translational mechanisms. Moreover, perturbations in these mechanisms can be involved in disease. This reveals multiple cellular mechanisms of kinetic and thermodynamic control that maintain the proper distribution of RNA molecules between dispersed and condensed forms.
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Affiliation(s)
- Devin Tauber
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80308, USA
| | - Gabriel Tauber
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80308, USA; Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80308, USA.
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8
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Bansal P, Madlung J, Schaaf K, Macek B, Bono F. An Interaction Network of RNA-Binding Proteins Involved in Drosophila Oogenesis. Mol Cell Proteomics 2020; 19:1485-1502. [PMID: 32554711 PMCID: PMC8143644 DOI: 10.1074/mcp.ra119.001912] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/26/2020] [Indexed: 12/31/2022] Open
Abstract
During Drosophila oogenesis, the localization and translational regulation of maternal transcripts relies on RNA-binding proteins (RBPs). Many of these RBPs localize several mRNAs and may have additional direct interaction partners to regulate their functions. Using immunoprecipitation from whole Drosophila ovaries coupled to mass spectrometry, we examined protein-protein associations of 6 GFP-tagged RBPs expressed at physiological levels. Analysis of the interaction network and further validation in human cells allowed us to identify 26 previously unknown associations, besides recovering several well characterized interactions. We identified interactions between RBPs and several splicing factors, providing links between nuclear and cytoplasmic events of mRNA regulation. Additionally, components of the translational and RNA decay machineries were selectively co-purified with some baits, suggesting a mechanism for how RBPs may regulate maternal transcripts. Given the evolutionary conservation of the studied RBPs, the interaction network presented here provides the foundation for future functional and structural studies of mRNA localization across metazoans.
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Affiliation(s)
- Prashali Bansal
- Living Systems Institute, University of Exeter, Exeter, UK; Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Johannes Madlung
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, Eberhard Karls University, Tübingen, Germany
| | - Kristina Schaaf
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Boris Macek
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, Eberhard Karls University, Tübingen, Germany
| | - Fulvia Bono
- Living Systems Institute, University of Exeter, Exeter, UK; Max Planck Institute for Developmental Biology, Tübingen, Germany.
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9
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Lasko P. Patterning the Drosophila embryo: A paradigm for RNA-based developmental genetic regulation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 11:e1610. [PMID: 32543002 PMCID: PMC7583483 DOI: 10.1002/wrna.1610] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/13/2020] [Accepted: 05/17/2020] [Indexed: 12/16/2022]
Abstract
Embryonic anterior–posterior patterning is established in Drosophila melanogaster by maternally expressed genes. The mRNAs of several of these genes accumulate at either the anterior or posterior pole of the oocyte via a number of mechanisms. Many of these mRNAs are also under elaborate translational regulation. Asymmetric RNA localization coupled with spatially restricted translation ensures that their proteins are restricted to the position necessary for the developmental process that they drive. Bicoid (Bcd), the anterior determinant, and Oskar (Osk), the determinant for primordial germ cells and posterior patterning, have been studied particularly closely. In early embryos an anterior–posterior gradient of Bcd is established, activating transcription of different sets of zygotic genes depending on local Bcd concentration. At the posterior pole, Osk seeds formation of polar granules, ribonucleoprotein complexes that accumulate further mRNAs and proteins involved in posterior patterning and germ cell specification. After fertilization, polar granules associate with posterior nuclei and mature into nuclear germ granules. Osk accumulates in these granules, and either by itself or as part of the granules, stimulates germ cell division. This article is categorized under:RNA Export and Localization > RNA Localization Translation > Translation Regulation RNA in Disease and Development > RNA in Development
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Affiliation(s)
- Paul Lasko
- Department of Biology, McGill University, Montréal, Québec, Canada.,Department of Human Genetics, Radboudumc, Nijmegen, Netherlands
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10
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Ribeiro AJM, Das S, Dawson N, Zaru R, Orchard S, Thornton JM, Orengo C, Zeqiraj E, Murphy JM, Eyers PA. Emerging concepts in pseudoenzyme classification, evolution, and signaling. Sci Signal 2019; 12:eaat9797. [PMID: 31409758 DOI: 10.1126/scisignal.aat9797] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The 21st century is witnessing an explosive surge in our understanding of pseudoenzyme-driven regulatory mechanisms in biology. Pseudoenzymes are proteins that have sequence homology with enzyme families but that are proven or predicted to lack enzyme activity due to mutations in otherwise conserved catalytic amino acids. The best-studied pseudoenzymes are pseudokinases, although examples from other families are emerging at a rapid rate as experimental approaches catch up with an avalanche of freely available informatics data. Kingdom-wide analysis in prokaryotes, archaea and eukaryotes reveals that between 5 and 10% of proteins that make up enzyme families are pseudoenzymes, with notable expansions and contractions seemingly associated with specific signaling niches. Pseudoenzymes can allosterically activate canonical enzymes, act as scaffolds to control assembly of signaling complexes and their localization, serve as molecular switches, or regulate signaling networks through substrate or enzyme sequestration. Molecular analysis of pseudoenzymes is rapidly advancing knowledge of how they perform noncatalytic functions and is enabling the discovery of unexpected, and previously unappreciated, functions of their intensively studied enzyme counterparts. Notably, upon further examination, some pseudoenzymes have previously unknown enzymatic activities that could not have been predicted a priori. Pseudoenzymes can be targeted and manipulated by small molecules and therefore represent new therapeutic targets (or anti-targets, where intervention should be avoided) in various diseases. In this review, which brings together broad bioinformatics and cell signaling approaches in the field, we highlight a selection of findings relevant to a contemporary understanding of pseudoenzyme-based biology.
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Affiliation(s)
- António J M Ribeiro
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Sayoni Das
- Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Natalie Dawson
- Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Rossana Zaru
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Sandra Orchard
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Janet M Thornton
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Christine Orengo
- Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Elton Zeqiraj
- Astbury Centre for Structural Molecular Biology, Molecular and Cellular Biology, Faculty of Biological Sciences, Astbury Building, Room 8.109, University of Leeds, Leeds LS2 9JT, UK
| | - James M Murphy
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Patrick A Eyers
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
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11
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A Novel Splice Variant of the Masculinizing Gene Masc with piRNA-Cleavage-Site Defect Functions in Female External Genital Development in the Silkworm, Bombyx mori. Biomolecules 2019; 9:biom9080318. [PMID: 31366115 PMCID: PMC6723575 DOI: 10.3390/biom9080318] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 07/20/2019] [Accepted: 07/29/2019] [Indexed: 12/31/2022] Open
Abstract
In the silkworm, the sex-determination primary signal Fem controls sex differentiation by specific binding of Fem-derived piRNA to the cleavage site in Masc mRNA, thus inhibiting Masc protein production in the female. In this study, we identified a novel splicing isoform of Masc, named Masc-S, which lacks the intact sequence of the cleavage site, encoding a C-terminal truncated protein. Results of RT-PCR showed that Masc-S was expressed in both sexes. Over-expression of Masc-S and Masc in female-specific cell lines showed that Masc-S could be translated against the Fem-piRNA cut. By RNA-protein pull-down, LC/MS/MS, and EMSA, we identified a protein BmEXU that specifically binds to an exclusive RNA sequence in Masc compared to Masc-S. Knockdown of Masc-S resulted in abnormal morphology in female external genital and increased expression of the Hox gene Abd-B, which similarly occurred by Bmexu RNAi. These results suggest that the splice variant Masc-S against Fem-piRNA plays an important role in female external genital development, of which function is opposite to that of full-length Masc. Our study provides new insights into the regulatory mechanism of sex determination in the silkworm.
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12
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Biochemical Fractionation of Time-Resolved Drosophila Embryos Reveals Similar Transcriptomic Alterations in Replication Checkpoint and Histone mRNA Processing Mutants. J Mol Biol 2017; 429:3264-3279. [DOI: 10.1016/j.jmb.2017.01.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/28/2017] [Accepted: 01/30/2017] [Indexed: 11/22/2022]
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13
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Evolutionary coincidence of adaptive changes in exuperantia and the emergence of bicoid in Cyclorrhapha (Diptera). Dev Genes Evol 2017; 227:355-365. [PMID: 28894941 PMCID: PMC5597691 DOI: 10.1007/s00427-017-0594-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 08/20/2017] [Indexed: 11/15/2022]
Abstract
The great radiation in the infraorder Cyclorrhapha involved several morphological and molecular changes, including important changes in anterior egg development. During Drosophila oogenesis, exuperantia (exu) is critical for localizing bicoid (bcd) messenger RNA (mRNA) to the anterior region of the oocyte. Because it is phylogenetically older than bcd, which is exclusive to Cyclorrhapha, we hypothesize that exu has undergone adaptive changes to enable this new function. Although exu has been well studied in Drosophila, there is no functional or transcriptional information about it in any other Diptera. Here, we investigate exu in the South American fruit fly Anastrepha fraterculus, a Cyclorrhapha of great agricultural importance that have lost bcd, aiming to understand the evolution of exu in this infraorder. We assessed its pattern of gene expression in A. fraterculus by analyzing transcriptomes from cephalic and reproductive tissues. A combination of next-generation data with classical sequencing procedures enabled identification of the structure of exu and its alternative transcripts in this species. In addition to the sex-specific isoforms described for Drosophila, we found that not only exu is expressed in heads, but this is mediated by two transcripts with a specific 5′UTR exon—likely a result from usage of a third promoter. Furthermore, we tested the hypothesis that exu is evolving under positive selection in Cyclorrhapha after divergence from lower Diptera. We found evidence of positive selection at two important exu domains, EXO-like and SAM-like, both involved with mRNA binding during bcd mRNA localization in Drosophila, which could reflect its cooptation for the new function of bcd mRNA localization in Cyclorrhapha.
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14
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Abstract
Asymmetric localization of mRNAs is a widespread gene regulatory mechanism that is crucial for many cellular processes. The localization of a transcript involves multiple steps and requires several protein factors to mediate transport, anchoring and translational repression of the mRNA. Specific recognition of the localizing transcript is a key step that depends on linear or structured localization signals, which are bound by RNA-binding proteins. Genetic studies have identified many components involved in mRNA localization. However, mechanistic aspects of the pathway are still poorly understood. Here we provide an overview of structural studies that contributed to our understanding of the mechanisms underlying mRNA localization, highlighting open questions and future challenges.
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Affiliation(s)
| | - Fulvia Bono
- a Max Planck Institute for Developmental Biology , Tübingen , Germany
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15
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Trovisco V, Belaya K, Nashchekin D, Irion U, Sirinakis G, Butler R, Lee JJ, Gavis ER, St Johnston D. bicoid mRNA localises to the Drosophila oocyte anterior by random Dynein-mediated transport and anchoring. eLife 2016; 5. [PMID: 27791980 PMCID: PMC5125753 DOI: 10.7554/elife.17537] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 10/25/2016] [Indexed: 01/17/2023] Open
Abstract
bicoid mRNA localises to the Drosophila oocyte anterior from stage 9 of oogenesis onwards to provide a local source for Bicoid protein for embryonic patterning. Live imaging at stage 9 reveals that bicoid mRNA particles undergo rapid Dynein-dependent movements near the oocyte anterior, but with no directional bias. Furthermore, bicoid mRNA localises normally in shot2A2, which abolishes the polarised microtubule organisation. FRAP and photo-conversion experiments demonstrate that the RNA is stably anchored at the anterior, independently of microtubules. Thus, bicoid mRNA is localised by random active transport and anterior anchoring. Super-resolution imaging reveals that bicoid mRNA forms 110-120 nm particles with variable RNA content, but constant size. These particles appear to be well-defined structures that package the RNA for transport and anchoring.
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Affiliation(s)
- Vítor Trovisco
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Katsiaryna Belaya
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Dmitry Nashchekin
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Uwe Irion
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - George Sirinakis
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Richard Butler
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
| | - Jack J Lee
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Elizabeth R Gavis
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Daniel St Johnston
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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