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Ustaoglu P, McQuarrie DWJ, Rochet A, Dix TC, Haussmann IU, Arnold R, Devaud JM, Soller M. Memory consolidation in honey bees is enhanced by down-regulation of Down syndrome cell adhesion molecule and changes its alternative splicing. Front Mol Neurosci 2024; 16:1322808. [PMID: 38264345 PMCID: PMC10803435 DOI: 10.3389/fnmol.2023.1322808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/13/2023] [Indexed: 01/25/2024] Open
Abstract
Down syndrome cell adhesion molecule (Dscam) gene encodes a cell adhesion molecule required for neuronal wiring. A remarkable feature of arthropod Dscam is massive alternative splicing generating thousands of different isoforms from three variable clusters of alternative exons. Dscam expression and diversity arising from alternative splicing have been studied during development, but whether they exert functions in adult brains has not been determined. Here, using honey bees, we find that Dscam expression is critically linked to memory retention as reducing expression by RNAi enhances memory after reward learning in adult worker honey bees. Moreover, alternative splicing of Dscam is altered in all three variable clusters after learning. Since identical Dscam isoforms engage in homophilic interactions, these results suggest a mechanism to alter inclusion of variable exons during memory consolidation to modify neuronal connections for memory retention.
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Affiliation(s)
- Pinar Ustaoglu
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
| | - David W. J. McQuarrie
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
| | - Anthony Rochet
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), CNRS, UPS, Toulouse University, Toulouse, France
| | - Thomas C. Dix
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
| | - Irmgard U. Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Life Science, Faculty of Health, Education and Life Sciences, Birmingham City University, Birmingham, United Kingdom
| | - Roland Arnold
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
- College of Medical and Dental Sciences, Institute of Cancer and Genomics Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Jean-Marc Devaud
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), CNRS, UPS, Toulouse University, Toulouse, France
- Institut Universitaire de France (IUF), Paris, France
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
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2
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CMTr cap-adjacent 2'-O-ribose mRNA methyltransferases are required for reward learning and mRNA localization to synapses. Nat Commun 2022; 13:1209. [PMID: 35260552 PMCID: PMC8904806 DOI: 10.1038/s41467-022-28549-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 01/18/2022] [Indexed: 11/25/2022] Open
Abstract
Cap-adjacent nucleotides of animal, protist and viral mRNAs can be O-methylated at the 2‘ position of the ribose (cOMe). The functions of cOMe in animals, however, remain largely unknown. Here we show that the two cap methyltransferases (CMTr1 and CMTr2) of Drosophila can methylate the ribose of the first nucleotide in mRNA. Double-mutant flies lack cOMe but are viable. Consistent with prominent neuronal expression, they have a reward learning defect that can be rescued by conditional expression in mushroom body neurons before training. Among CMTr targets are cell adhesion and signaling molecules. Many are relevant for learning, and are also targets of Fragile X Mental Retardation Protein (FMRP). Like FMRP, cOMe is required for localization of untranslated mRNAs to synapses and enhances binding of the cap binding complex in the nucleus. Hence, our study reveals a mechanism to co-transcriptionally prime mRNAs by cOMe for localized protein synthesis at synapses. The two cap methyltransferases (CMTrs) redundantly methylate riboses of first cap adjacent nucleotides in messenger RNAs in Drosophila. Here, CMTrs are required for reward learning and localization of untranslated messenger RNAs to synapses.
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3
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Wei L, Lai EC. Regulation of the Alternative Neural Transcriptome by ELAV/Hu RNA Binding Proteins. Front Genet 2022; 13:848626. [PMID: 35281806 PMCID: PMC8904962 DOI: 10.3389/fgene.2022.848626] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 02/01/2022] [Indexed: 11/30/2022] Open
Abstract
The process of alternative polyadenylation (APA) generates multiple 3' UTR isoforms for a given locus, which can alter regulatory capacity and on occasion change coding potential. APA was initially characterized for a few genes, but in the past decade, has been found to be the rule for metazoan genes. While numerous differences in APA profiles have been catalogued across genetic conditions, perturbations, and diseases, our knowledge of APA mechanisms and biology is far from complete. In this review, we highlight recent findings regarding the role of the conserved ELAV/Hu family of RNA binding proteins (RBPs) in generating the broad landscape of lengthened 3' UTRs that is characteristic of neurons. We relate this to their established roles in alternative splicing, and summarize ongoing directions that will further elucidate the molecular strategies for neural APA, the in vivo functions of ELAV/Hu RBPs, and the phenotypic consequences of these regulatory paradigms in neurons.
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Affiliation(s)
- Lu Wei
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Eric C. Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, United States
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4
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Ustaoglu P, Gill JK, Doubovetzky N, Haussmann IU, Dix TC, Arnold R, Devaud JM, Soller M. Dynamically expressed single ELAV/Hu orthologue elavl2 of bees is required for learning and memory. Commun Biol 2021; 4:1234. [PMID: 34711922 PMCID: PMC8553928 DOI: 10.1038/s42003-021-02763-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 10/09/2021] [Indexed: 12/16/2022] Open
Abstract
Changes in gene expression are a hallmark of learning and memory consolidation. Little is known about how alternative mRNA processing, particularly abundant in neuron-specific genes, contributes to these processes. Prototype RNA binding proteins of the neuronally expressed ELAV/Hu family are candidates for roles in learning and memory, but their capacity to cross-regulate and take over each other's functions complicate substantiation of such links. Honey bees Apis mellifera have only one elav/Hu family gene elavl2, that has functionally diversified by increasing alternative splicing including an evolutionary conserved microexon. RNAi knockdown demonstrates that ELAVL2 is required for learning and memory in bees. ELAVL2 is dynamically expressed with altered alternative splicing and subcellular localization in mushroom bodies, but not in other brain regions. Expression and alternative splicing of elavl2 change during memory consolidation illustrating an alternative mRNA processing program as part of a local gene expression response underlying memory consolidation.
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Affiliation(s)
- Pinar Ustaoglu
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jatinder Kaur Gill
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Nicolas Doubovetzky
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, 31062, France
| | - Irmgard U Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Department of Life Science, Faculty of Health, Education and Life Sciences, Birmingham City University, Birmingham, B15 3TN, UK
| | - Thomas C Dix
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Roland Arnold
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Institute of Cancer and Genomics Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jean-Marc Devaud
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, 31062, France
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
- Institute of Cancer and Genomics Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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5
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Nallasivan MP, Haussmann IU, Civetta A, Soller M. Channel nuclear pore protein 54 directs sexual differentiation and neuronal wiring of female reproductive behaviors in Drosophila. BMC Biol 2021; 19:226. [PMID: 34666772 PMCID: PMC8527774 DOI: 10.1186/s12915-021-01154-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 09/15/2021] [Indexed: 11/23/2022] Open
Abstract
Background Female reproductive behaviors and physiology change profoundly after mating. The control of pregnancy-associated changes in physiology and behaviors are largely hard-wired into the brain to guarantee reproductive success, yet the gene expression programs that direct neuronal differentiation and circuit wiring at the end of the sex determination pathway in response to mating are largely unknown. In Drosophila, the post-mating response induced by male-derived sex-peptide in females is a well-established model to elucidate how complex innate behaviors are hard-wired into the brain. Here, we use a genetic approach to further characterize the molecular and cellular architecture of the sex-peptide response in Drosophila females. Results Screening for mutations that affect the sensitivity to sex-peptide, we identified the channel nuclear pore protein Nup54 gene as an essential component for mediating the sex-peptide response, with viable mutant alleles leading to the inability of laying eggs and reducing receptivity upon sex-peptide exposure. Nup54 directs correct wiring of eight adult brain neurons that express pickpocket and are required for egg-laying, while additional channel Nups also mediate sexual differentiation. Consistent with links of Nups to speciation, the Nup54 promoter is a hot spot for rapid evolution and promoter variants alter nucleo-cytoplasmic shuttling. Conclusions These results implicate nuclear pore functionality to neuronal wiring underlying the sex-peptide response and sexual differentiation as a response to sexual conflict arising from male-derived sex-peptide to direct the female post-mating response. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01154-6.
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Affiliation(s)
- Mohanakarthik P Nallasivan
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Irmgard U Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Department of Life Science, School of Health Sciences, Birmingham City University, Birmingham, B15 3TN, UK
| | - Alberto Civetta
- Department of Biology, University of Winnipeg, Winnipeg, MB, R3B 2E9, Canada
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. .,Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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6
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Decio P, Ustaoglu P, Derecka K, Hardy ICW, Roat TC, Malaspina O, Mongan N, Stöger R, Soller M. Thiamethoxam exposure deregulates short ORF gene expression in the honey bee and compromises immune response to bacteria. Sci Rep 2021; 11:1489. [PMID: 33452318 PMCID: PMC7811001 DOI: 10.1038/s41598-020-80620-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 12/23/2020] [Indexed: 01/29/2023] Open
Abstract
Maximizing crop yields relies on the use of agrochemicals to control insect pests. One of the most widely used classes of insecticides are neonicotinoids that interfere with signalling of the neurotransmitter acetylcholine, but these can also disrupt crop-pollination services provided by bees. Here, we analysed whether chronic low dose long-term exposure to the neonicotinoid thiamethoxam alters gene expression and alternative splicing in brains of Africanized honey bees, Apis mellifera, as adaptation to altered neuronal signalling. We find differentially regulated genes that show concentration-dependent responses to thiamethoxam, but no changes in alternative splicing. Most differentially expressed genes have no annotated function but encode short Open Reading Frames, a characteristic feature of anti-microbial peptides. As this suggested that immune responses may be compromised by thiamethoxam exposure, we tested the impact of thiamethoxam on bee immunity by injecting bacteria. We show that intrinsically sub-lethal thiamethoxam exposure makes bees more vulnerable to normally non-pathogenic bacteria. Our findings imply a synergistic mechanism for the observed bee population declines that concern agriculturists, conservation ecologists and the public.
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Affiliation(s)
- Pâmela Decio
- grid.410543.70000 0001 2188 478XInstitute of Biosciences, São Paulo State University (Unesp), Rio Claro, Brazil
| | - Pinar Ustaoglu
- grid.6572.60000 0004 1936 7486School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
| | - Kamila Derecka
- grid.4563.40000 0004 1936 8868School of Biosciences, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD UK
| | - Ian C. W. Hardy
- grid.4563.40000 0004 1936 8868School of Biosciences, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD UK
| | - Thaisa C. Roat
- grid.410543.70000 0001 2188 478XInstitute of Biosciences, São Paulo State University (Unesp), Rio Claro, Brazil
| | - Osmar Malaspina
- grid.410543.70000 0001 2188 478XInstitute of Biosciences, São Paulo State University (Unesp), Rio Claro, Brazil
| | - Nigel Mongan
- grid.4563.40000 0004 1936 8868School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD UK
| | - Reinhard Stöger
- grid.4563.40000 0004 1936 8868School of Biosciences, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD UK
| | - Matthias Soller
- grid.6572.60000 0004 1936 7486School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
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7
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Wei L, Lee S, Majumdar S, Zhang B, Sanfilippo P, Joseph B, Miura P, Soller M, Lai EC. Overlapping Activities of ELAV/Hu Family RNA Binding Proteins Specify the Extended Neuronal 3' UTR Landscape in Drosophila. Mol Cell 2020; 80:140-155.e6. [PMID: 33007254 DOI: 10.1016/j.molcel.2020.09.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/31/2020] [Accepted: 09/04/2020] [Indexed: 12/21/2022]
Abstract
The tissue-specific deployment of highly extended neural 3' UTR isoforms, generated by alternative polyadenylation (APA), is a broad and conserved feature of metazoan genomes. However, the factors and mechanisms that control neural APA isoforms are not well understood. Here, we show that three ELAV/Hu RNA binding proteins (Elav, Rbp9, and Fne) have similar capacities to induce a lengthened 3' UTR landscape in an ectopic setting. These factors promote accumulation of chromatin-associated, 3' UTR-extended, nascent transcripts, through inhibition of proximal polyadenylation site (PAS) usage. Notably, Elav represses an unannotated splice isoform of fne, switching the normally cytoplasmic Fne toward the nucleus in elav mutants. We use genomic profiling to reveal strong and broad loss of neural APA in elav/fne double mutant CNS, the first genetic background to largely abrogate this distinct APA signature. Overall, we demonstrate how regulatory interplay and functionally overlapping activities of neural ELAV/Hu RBPs drives the neural APA landscape.
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Affiliation(s)
- Lu Wei
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA
| | - Seungjae Lee
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA
| | - Sonali Majumdar
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA
| | - Binglong Zhang
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA
| | - Piero Sanfilippo
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA; Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Brian Joseph
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA; Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Pedro Miura
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA; Department of Biology, University of Nevada, Reno, Reno, NV 89557, USA
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Eric C Lai
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA.
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8
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Decio P, Ustaoglu P, Roat TC, Malaspina O, Devaud JM, Stöger R, Soller M. Acute thiamethoxam toxicity in honeybees is not enhanced by common fungicide and herbicide and lacks stress-induced changes in mRNA splicing. Sci Rep 2019; 9:19196. [PMID: 31844097 PMCID: PMC6915785 DOI: 10.1038/s41598-019-55534-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 11/20/2019] [Indexed: 12/19/2022] Open
Abstract
Securing food supply for a growing population is a major challenge and heavily relies on the use of agrochemicals to maximize crop yield. It is increasingly recognized, that some neonicotinoid insecticides have a negative impact on non-target organisms, including important pollinators such as the European honeybee Apis mellifera. Toxicity of neonicotinoids may be enhanced through simultaneous exposure with additional pesticides, which could help explain, in part, the global decline of honeybee colonies. Here we examined whether exposure effects of the neonicotinoid thiamethoxam on bee viability are enhanced by the commonly used fungicide carbendazim and the herbicide glyphosate. We also analysed alternative splicing changes upon pesticide exposure in the honeybee. In particular, we examined transcripts of three genes: (i) the stress sensor gene X box binding protein-1 (Xbp1), (ii) the Down Syndrome Cell Adhesion Molecule (Dscam) gene and iii) the embryonic lethal/abnormal visual system (elav) gene, which are important for neuronal function. Our results showed that acute thiamethoxam exposure is not enhanced by carbendazim, nor glyphosate. Toxicity of the compounds did not trigger stress-induced, alternative splicing in the analysed mRNAs, thereby leaving dormant a cellular response pathway to these man-made environmental perturbations.
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Affiliation(s)
- Pâmela Decio
- Universidade Estadual Paulista (UNESP), Instituto de Biociências, Centro de Estudos de Insetos Sociais, Rio Claro, São Paulo, Brazil
| | - Pinar Ustaoglu
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
- MRC Centre for Molecular Bacteriology and Infection, and Department of Life Sciences, Imperial College London, Ground Floor, Flowers Building, South Kensington Campus, London, SW7 2AZ, UK
| | - Thaisa C Roat
- Universidade Estadual Paulista (UNESP), Instituto de Biociências, Centro de Estudos de Insetos Sociais, Rio Claro, São Paulo, Brazil
| | - Osmar Malaspina
- Universidade Estadual Paulista (UNESP), Instituto de Biociências, Centro de Estudos de Insetos Sociais, Rio Claro, São Paulo, Brazil
| | - Jean-Marc Devaud
- Research Center on Animal Cognition, Center for Integrative Biology, Toulouse University, CNRS, UPS, Toulouse, France
| | - Reinhard Stöger
- School of Biosciences, University of Nottingham, LE12 5RD, Nottingham/Sutton Bonington Campus, United Kingdom.
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
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9
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Ustaoglu P, Haussmann IU, Liao H, Torres-Mendez A, Arnold R, Irimia M, Soller M. Srrm234, but not canonical SR and hnRNP proteins, drive inclusion of Dscam exon 9 variable exons. RNA (NEW YORK, N.Y.) 2019; 25:1353-1365. [PMID: 31292260 PMCID: PMC6800468 DOI: 10.1261/rna.071316.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/04/2019] [Indexed: 05/24/2023]
Abstract
Alternative splicing of pre-mRNA is a major mechanism to diversify protein functionality in metazoans from a limited number of genes. The Drosophila melanogaster Down syndrome cell adhesion molecule (Dscam) gene, which is important for neuronal wiring and phagocytosis of bacteria, can generate up to 38,016 isoforms by mutually exclusive alternative splicing in four clusters of variable exons. However, it is not understood how a specific exon is chosen from the many variables and how variable exons are prevented from being spliced together. A main role in the regulation of Dscam alternative splicing has been attributed to RNA binding proteins (RBPs), but how they impact on exon selection is not well understood. Serine-arginine rich (SR) proteins and hnRNP proteins are the two main types of RBPs with major roles in exon definition and splice site selection. Here, we analyzed the role of SR and hnRNP proteins in Dscam exon 9 alternative splicing in mutant Drosophila melanogaster embryos because of their essential function for development. Strikingly, loss or overexpression of canonical SR and hnRNP proteins even when multiple proteins are depleted together, does not affect Dscam alternative exon selection very dramatically. Conversely, noncanonical SR protein Serine-arginine repetitive matrix 2/3/4 (Srrm234) is a main determinant of exon inclusion in the Dscam exon 9 cluster. Since long-range base-pairings are absent in the exon 9 cluster, our data argue for a small complement of regulatory factors as main determinants of exon inclusion in the Dscam exon 9 cluster.
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Affiliation(s)
- Pinar Ustaoglu
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Irmgard U Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
- Department of Life Science, School of Health Sciences, Birmingham City University, Birmingham B5 3TN, United Kingdom
| | - Hongzhi Liao
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Antonio Torres-Mendez
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - Roland Arnold
- Institute of Cancer and Genomics Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Manuel Irimia
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain
- ICREA, Barcelona 08010, Spain
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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10
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Haussmann IU, Ustaoglu P, Brauer U, Hemani Y, Dix TC, Soller M. Plasmid-based gap-repair recombineered transgenes reveal a central role for introns in mutually exclusive alternative splicing in Down Syndrome Cell Adhesion Molecule exon 4. Nucleic Acids Res 2019; 47:1389-1403. [PMID: 30541104 PMCID: PMC6379703 DOI: 10.1093/nar/gky1254] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/22/2018] [Accepted: 12/03/2018] [Indexed: 12/18/2022] Open
Abstract
Alternative splicing is a key feature of human genes, yet studying its regulation is often complicated by large introns. The Down Syndrome Cell Adhesion Molecule (Dscam) gene from Drosophila is one of the most complex genes generating vast molecular diversity by mutually exclusive alternative splicing. To resolve how alternative splicing in Dscam is regulated, we first developed plasmid-based UAS reporter genes for the Dscam variable exon 4 cluster and show that its alternative splicing is recapitulated by GAL4-mediated expression in neurons. We then developed gap-repair recombineering to very efficiently manipulate these large reporter plasmids in Escherichia coli using restriction enzymes or sgRNA/Cas9 DNA scission to capitalize on the many benefits of plasmids in phiC31 integrase-mediated transgenesis. Using these novel tools, we show that inclusion of Dscam exon 4 variables differs little in development and individual flies, and is robustly determined by sequences harbored in variable exons. We further show that introns drive selection of both proximal and distal variable exons. Since exon 4 cluster introns lack conserved sequences that could mediate robust long-range base-pairing to bring exons into proximity for splicing, our data argue for a central role of introns in mutually exclusive alternative splicing of Dscam exon 4 cluster.
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Affiliation(s)
- Irmgard U Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.,School of Life Science, CSELS, Coventry University, Coventry CV1 5FB, UK
| | - Pinar Ustaoglu
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Ulrike Brauer
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Yash Hemani
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Thomas C Dix
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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11
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Haussmann IU, Bodi Z, Sanchez-Moran E, Mongan NP, Archer N, Fray RG, Soller M. m6A potentiates Sxl alternative pre-mRNA splicing for robust Drosophila sex determination. Nature 2016; 540:301-304. [DOI: 10.1038/nature20577] [Citation(s) in RCA: 359] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 10/25/2016] [Indexed: 12/28/2022]
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12
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Concentration and Localization of Coexpressed ELAV/Hu Proteins Control Specificity of mRNA Processing. Mol Cell Biol 2015; 35:3104-15. [PMID: 26124284 DOI: 10.1128/mcb.00473-15] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 06/10/2015] [Indexed: 01/25/2023] Open
Abstract
Neuronally coexpressed ELAV/Hu proteins comprise a family of highly related RNA binding proteins which bind to very similar cognate sequences. How this redundancy is linked to in vivo function and how gene-specific regulation is achieved have not been clear. Analysis of mutants in Drosophila ELAV/Hu family proteins ELAV, FNE, and RBP9 and of genetic interactions among them indicates that they have mostly independent roles in neuronal development and function but have converging roles in the regulation of synaptic plasticity. Conversely, ELAV, FNE, RBP9, and human HuR bind ELAV target RNA in vitro with similar affinities. Likewise, all can regulate alternative splicing of ELAV target genes in nonneuronal wing disc cells and substitute for ELAV in eye development upon artificially increased expression; they can also substantially restore ELAV's biological functions when expressed under the control of the elav gene. Furthermore, ELAV-related Sex-lethal can regulate ELAV targets, and ELAV/Hu proteins can interfere with sexual differentiation. An ancient relationship to Sex-lethal is revealed by gonadal expression of RBP9, providing a maternal fail-safe for dosage compensation. Our results indicate that highly related ELAV/Hu RNA binding proteins select targets for mRNA processing through alteration of their expression levels and subcellular localization but only minimally by altered RNA binding specificity.
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Abstract
ELAV (embryonic lethal/abnormal visual system)/Hu proteins comprise a family of highly related neuronal RBPs (RNA-binding proteins) involved in many aspects of mRNA processing. Although they bind to highly similar short sequence motifs, they have acquired diverse functions suggesting that cellular signalling is important for their functional diversification. Indeed, ELAV/Hu proteins harbour many phosphorylatable amino acids. In the present article, we review our current knowledge about phosphorylation of ELAV/Hu proteins and how phosphorylation affects cellular localization of ELAV/Hu proteins and their binding to RNA.
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Haussmann IU, Hemani Y, Wijesekera T, Dauwalder B, Soller M. Multiple pathways mediate the sex-peptide-regulated switch in female Drosophila reproductive behaviours. Proc Biol Sci 2013; 280:20131938. [PMID: 24089336 DOI: 10.1098/rspb.2013.1938] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Male-derived sex-peptide (SP) induces profound changes in the behaviour of Drosophila females, resulting in decreased receptivity to further mating and increased egg laying. SP can mediate the switch in female reproductive behaviours via a G protein-coupled receptor, SPR, in neurons expressing fruitless, doublesex and pickpocket. Whether SPR is the sole receptor and whether SP induces the postmating switch in a single pathway has not, to our knowledge been tested. Here we report that the SP response can be induced in the absence of SPR when SP is ectopically expressed in neurons or when SP, transferred by mating, can access neurons through a leaky blood brain barrier. Membrane-tethered SP can induce oviposition via doublesex, but not fruitless and pickpocket neurons in SPR mutant females. Although pickpocket and doublesex neurons rely on G(o) signalling to reduce receptivity and induce oviposition, G(o) signalling in fruitless neurons is required only to induce oviposition, but not to reduce receptivity. Our results show that SP's action in reducing receptivity and inducing oviposition can be separated in fruitless and doublesex neurons. Hence, the SP-induced postmating switch incorporates shared, but also distinct circuitry of fruitless, doublesex and pickpocket neurons and additional receptors.
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Affiliation(s)
- Irmgard U Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, , Birmingham B15 2TT, UK, Department of Biology and Biochemistry, University of Houston, , Houston, TX, USA
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Alternative splicing interference by xenobiotics. Toxicology 2012; 296:1-12. [DOI: 10.1016/j.tox.2012.01.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/21/2012] [Accepted: 01/23/2012] [Indexed: 12/21/2022]
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