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Aughey GN, Forsberg E, Grimes K, Zhang S, Southall TD. NuRD-independent Mi-2 activity represses ectopic gene expression during neuronal maturation. EMBO Rep 2023; 24:e55362. [PMID: 36722816 PMCID: PMC10074086 DOI: 10.15252/embr.202255362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 01/10/2023] [Accepted: 01/16/2023] [Indexed: 02/02/2023] Open
Abstract
During neuronal development, extensive changes to chromatin states occur to regulate lineage-specific gene expression. The molecular factors underlying the repression of non-neuronal genes in differentiated neurons are poorly characterised. The Mi2/NuRD complex is a multiprotein complex with nucleosome remodelling and histone deacetylase activity. Whilst NuRD has previously been implicated in the development of nervous system tissues, the precise nature of the gene expression programmes that it coordinates is ill-defined. Furthermore, evidence from several species suggests that Mi-2 may be incorporated into multiple complexes that may not possess histone deacetylase activity. We show that Mi-2 activity is required for suppressing ectopic expression of germline genes in neurons independently of HDAC1/NuRD, whilst components of NuRD, including Mi-2, regulate neural gene expression to ensure proper development of the larval nervous system. We find that Mi-2 binding in the genome is dynamic during neuronal maturation, and Mi-2-mediated repression of ectopic gene expression is restricted to the early stages of neuronal development, indicating that Mi-2/NuRD is required for establishing stable neuronal transcriptomes during the early stages of neuronal differentiation.
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Affiliation(s)
- Gabriel N Aughey
- Department of Life Sciences, Imperial College London, London, UK
| | - Elhana Forsberg
- Department of Life Sciences, Imperial College London, London, UK
| | - Krista Grimes
- Department of Life Sciences, Imperial College London, London, UK
| | - Shen Zhang
- Department of Life Sciences, Imperial College London, London, UK
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, London, UK
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2
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Martínez Corrales G, Li M, Svermova T, Goncalves A, Voicu D, Dobson AJ, Southall TD, Alic N. Transcriptional memory of dFOXO activation in youth curtails later-life mortality through chromatin remodeling and Xbp1. Nat Aging 2022; 2:1176-1190. [PMID: 37118537 PMCID: PMC7614430 DOI: 10.1038/s43587-022-00312-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 10/19/2022] [Indexed: 12/03/2022]
Abstract
A transient, homeostatic transcriptional response can result in transcriptional memory, programming subsequent transcriptional outputs. Transcriptional memory has great but unappreciated potential to alter animal ageing as animals encounter a multitude of diverse stimuli throughout their lifespan. Here we show that activating an evolutionarily conserved, longevity-promoting transcription factor, dFOXO, solely in early adulthood of female fruit flies is sufficient to improve their subsequent health and survival in mid- and late life. This youth-restricted dFOXO activation causes persistent changes to chromatin landscape in the fat body and requires chromatin remodellers such as the SWI/SNF and ISWI complexes to program health and longevity. Chromatin remodelling is accompanied by a long-lasting transcriptional programme that is distinct from that observed during acute dFOXO activation and includes induction of Xbp1. We show that this later-life induction of Xbp1 is sufficient to curtail later-life mortality. Our study demonstrates that transcriptional memory can profoundly alter how animals age.
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3
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Sênos Demarco R, Stack BJ, Tang AM, Voog J, Sandall SL, Southall TD, Brand AH, Jones DL. Escargot controls somatic stem cell maintenance through the attenuation of the insulin receptor pathway in Drosophila. Cell Rep 2022; 39:110679. [PMID: 35443165 PMCID: PMC9043617 DOI: 10.1016/j.celrep.2022.110679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 11/24/2021] [Accepted: 03/23/2022] [Indexed: 02/07/2023] Open
Abstract
Adult stem cells coordinate intrinsic and extrinsic, local and systemic, cues to maintain the proper balance between self-renewal and differentiation. However, the precise mechanisms stem cells use to integrate these signals remain elusive. Here, we show that Escargot (Esg), a member of the Snail family of transcription factors, regulates the maintenance of somatic cyst stem cells (CySCs) in the Drosophila testis by attenuating the activity of the pro-differentiation insulin receptor (InR) pathway. Esg positively regulates the expression of an antagonist of insulin signaling, ImpL2, while also attenuating the expression of InR. Furthermore, Esg-mediated repression of the InR pathway is required to suppress CySC loss in response to starvation. Given the conservation of Snail-family transcription factors, characterizing the mechanisms by which Esg regulates cell-fate decisions during homeostasis and a decline in nutrient availability is likely to provide insight into the metabolic regulation of stem cell behavior in other tissues and organisms.
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Affiliation(s)
- Rafael Sênos Demarco
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Brian J Stack
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alexander M Tang
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Justin Voog
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Sharsti L Sandall
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 1QN, UK
| | - D Leanne Jones
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Anatomy, Division of Geriatrics, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Medicine, Division of Geriatrics, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center for Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA.
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4
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McClure CD, Hassan A, Aughey GN, Butt K, Estacio-Gómez A, Duggal A, Ying Sia C, Barber AF, Southall TD. An auxin-inducible, GAL4-compatible, gene expression system for Drosophila. eLife 2022; 11:e67598. [PMID: 35363137 PMCID: PMC8975555 DOI: 10.7554/elife.67598] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 03/27/2022] [Indexed: 01/04/2023] Open
Abstract
The ability to control transgene expression, both spatially and temporally, is essential for studying model organisms. In Drosophila, spatial control is primarily provided by the GAL4/UAS system, whilst temporal control relies on a temperature-sensitive GAL80 (which inhibits GAL4) and drug-inducible systems. However, these are not ideal. Shifting temperature can impact on many physiological and behavioural traits, and the current drug-inducible systems are either leaky, toxic, incompatible with existing GAL4-driver lines, or do not generate effective levels of expression. Here, we describe the auxin-inducible gene expression system (AGES). AGES relies on the auxin-dependent degradation of a ubiquitously expressed GAL80, and therefore, is compatible with existing GAL4-driver lines. Water-soluble auxin is added to fly food at a low, non-lethal, concentration, which induces expression comparable to uninhibited GAL4 expression. The system works in both larvae and adults, providing a stringent, non-lethal, cost-effective, and convenient method for temporally controlling GAL4 activity in Drosophila.
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Affiliation(s)
- Colin D McClure
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Amira Hassan
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Gabriel N Aughey
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Khushbakht Butt
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers, the State University of New JerseyNew BrunswickUnited States
| | | | - Aneisha Duggal
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Chee Ying Sia
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Annika F Barber
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers, the State University of New JerseyNew BrunswickUnited States
| | - Tony D Southall
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
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5
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Katsanos D, Ferrando-Marco M, Razzaq I, Aughey G, Southall TD, Barkoulas M. Gene expression profiling of epidermal cell types in C. elegans using Targeted DamID. Development 2021; 148:dev199452. [PMID: 34397094 PMCID: PMC7613258 DOI: 10.1242/dev.199452] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 08/05/2021] [Indexed: 12/19/2022]
Abstract
The epidermis of Caenorhabditis elegans is an essential tissue for survival because it contributes to the formation of the cuticle barrier as well as facilitating developmental progression and animal growth. Most of the epidermis consists of the hyp7 hypodermal syncytium, the nuclei of which are largely generated by the seam cells, which exhibit stem cell-like behaviour during development. How seam cell progenitors differ transcriptionally from the differentiated hypodermis is poorly understood. Here, we introduce Targeted DamID (TaDa) in C. elegans as a method for identifying genes expressed within a tissue of interest without cell isolation. We show that TaDa signal enrichment profiles can be used to identify genes transcribed in the epidermis and use this method to resolve differences in gene expression between the seam cells and the hypodermis. Finally, we predict and functionally validate new transcription and chromatin factors acting in seam cell development. These findings provide insights into cell type-specific gene expression profiles likely associated with epidermal cell fate patterning.
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Affiliation(s)
- Dimitris Katsanos
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Mar Ferrando-Marco
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Iqrah Razzaq
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Gabriel Aughey
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Tony D. Southall
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Michalis Barkoulas
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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6
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Aughey GN, Delandre C, McMullen JPD, Southall TD, Marshall OJ. FlyORF-TaDa allows rapid generation of new lines for in vivo cell-type-specific profiling of protein-DNA interactions in Drosophila melanogaster. G3 (Bethesda) 2021; 11:6044134. [PMID: 33561239 PMCID: PMC8022459 DOI: 10.1093/g3journal/jkaa005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/07/2020] [Indexed: 12/01/2022]
Abstract
Targeted DamID (TaDa) is an increasingly popular method of generating cell-type-specific DNA-binding profiles in vivo. Although sensitive and versatile, TaDa requires the generation of new transgenic fly lines for every protein that is profiled, which is both time-consuming and costly. Here, we describe the FlyORF-TaDa system for converting an existing FlyORF library of inducible open reading frames (ORFs) to TaDa lines via a genetic cross, with recombinant progeny easily identifiable by eye color. Profiling the binding of the H3K36me3-associated chromatin protein MRG15 in larval neural stem cells using both FlyORF-TaDa and conventional TaDa demonstrates that new lines generated using this system provide accurate and highly reproducible DamID-binding profiles. Our data further show that MRG15 binds to a subset of active chromatin domains in vivo. Courtesy of the large coverage of the FlyORF library, the FlyORF-TaDa system enables the easy creation of TaDa lines for 74% of all transcription factors and chromatin-modifying proteins within the Drosophila genome.
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Affiliation(s)
- Gabriel N Aughey
- Imperial College London, Sir Ernst Chain Building, South Kensington Campus, London SW7 2AZ, UK
| | - Caroline Delandre
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool St, Hobart 7000, Australia
| | - John P D McMullen
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool St, Hobart 7000, Australia
| | - Tony D Southall
- Imperial College London, Sir Ernst Chain Building, South Kensington Campus, London SW7 2AZ, UK
| | - Owen J Marshall
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool St, Hobart 7000, Australia
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7
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Estacio-Gómez A, Hassan A, Walmsley E, Le LW, Southall TD. Dynamic neurotransmitter specific transcription factor expression profiles during Drosophila development. Biol Open 2020; 9:9/5/bio052928. [PMID: 32493733 PMCID: PMC7286294 DOI: 10.1242/bio.052928] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The remarkable diversity of neurons in the nervous system is generated during development, when properties such as cell morphology, receptor profiles and neurotransmitter identities are specified. In order to gain a greater understanding of neurotransmitter specification we profiled the transcription state of cholinergic, GABAergic and glutamatergic neurons in vivo at three developmental time points. We identified 86 differentially expressed transcription factors that are uniquely enriched, or uniquely depleted, in a specific neurotransmitter type. Some transcription factors show a similar profile across development, others only show enrichment or depletion at specific developmental stages. Profiling of Acj6 (cholinergic enriched) and Ets65A (cholinergic depleted) binding sites in vivo reveals that they both directly bind the ChAT locus, in addition to a wide spectrum of other key neuronal differentiation genes. We also show that cholinergic enriched transcription factors are expressed in mostly non-overlapping populations in the adult brain, implying the absence of combinatorial regulation of neurotransmitter fate in this context. Furthermore, our data underlines that, similar to Caenorhabditis elegans, there are no simple transcription factor codes for neurotransmitter type specification. This article has an associated First Person interview with the first author of the paper. Summary: Transcriptome profiling of cholinergic, GABAergic and glutamatergic neurons in Drosophila identified multiple transcription factors as potential regulators of neurotransmitter fate.
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Affiliation(s)
- Alicia Estacio-Gómez
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Amira Hassan
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Emma Walmsley
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Lily Wong Le
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
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8
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Hassan A, Araguas Rodriguez P, Heidmann SK, Walmsley EL, Aughey GN, Southall TD. Condensin I subunit Cap-G is essential for proper gene expression during the maturation of post-mitotic neurons. eLife 2020; 9:e55159. [PMID: 32255428 PMCID: PMC7170655 DOI: 10.7554/elife.55159] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/06/2020] [Indexed: 02/07/2023] Open
Abstract
Condensin complexes are essential for mitotic chromosome assembly and segregation during cell divisions, however, little is known about their functions in post-mitotic cells. Here we report a role for the condensin I subunit Cap-G in Drosophila neurons. We show that, despite not requiring condensin for mitotic chromosome compaction, post-mitotic neurons express Cap-G. Knockdown of Cap-G specifically in neurons (from their birth onwards) results in developmental arrest, behavioural defects, and dramatic gene expression changes, including reduced expression of a subset of neuronal genes and aberrant expression of genes that are not normally expressed in the developing brain. Knockdown of Cap-G in mature neurons results in similar phenotypes but to a lesser degree. Furthermore, we see dynamic binding of Cap-G at distinct loci in progenitor cells and differentiated neurons. Therefore, Cap-G is essential for proper gene expression in neurons and plays an important role during the early stages of neuronal development.
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Affiliation(s)
- Amira Hassan
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | | | | | - Emma L Walmsley
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Gabriel N Aughey
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Tony D Southall
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
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9
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Mundorf J, Donohoe CD, McClure CD, Southall TD, Uhlirova M. Ets21c Governs Tissue Renewal, Stress Tolerance, and Aging in the Drosophila Intestine. Cell Rep 2019; 27:3019-3033.e5. [PMID: 31167145 PMCID: PMC6581828 DOI: 10.1016/j.celrep.2019.05.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 04/04/2019] [Accepted: 05/06/2019] [Indexed: 02/07/2023] Open
Abstract
Homeostatic renewal and stress-related tissue regeneration rely on stem cell activity, which drives the replacement of damaged cells to maintain tissue integrity and function. The Jun N-terminal kinase (JNK) signaling pathway has been established as a critical regulator of tissue homeostasis both in intestinal stem cells (ISCs) and mature enterocytes (ECs), while its chronic activation has been linked to tissue degeneration and aging. Here, we show that JNK signaling requires the stress-inducible transcription factor Ets21c to promote tissue renewal in Drosophila. We demonstrate that Ets21c controls ISC proliferation as well as EC apoptosis through distinct sets of target genes that orchestrate cellular behaviors via intrinsic and non-autonomous signaling mechanisms. While its loss appears dispensable for development and prevents epithelial aging, ISCs and ECs demand Ets21c function to mount cellular responses to oxidative stress. Ets21c thus emerges as a vital regulator of proliferative homeostasis in the midgut and a determinant of the adult healthspan.
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Affiliation(s)
- Juliane Mundorf
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Colin D Donohoe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Colin D McClure
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, South Kensington Campus, London SW7 2AZ, UK
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, South Kensington Campus, London SW7 2AZ, UK
| | - Mirka Uhlirova
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne 50931, Germany.
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10
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Sharrock J, Estacio-Gomez A, Jacobson J, Kierdorf K, Southall TD, Dionne MS. fs(1)h controls metabolic and immune function and enhances survival via AKT and FOXO in Drosophila. Dis Model Mech 2019; 12:dmm.037259. [PMID: 30910908 PMCID: PMC6505478 DOI: 10.1242/dmm.037259] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 03/15/2019] [Indexed: 12/14/2022] Open
Abstract
The Drosophila fat body is the primary organ of energy storage as well as being responsible for the humoral response to infection. Its physiological function is of critical importance to the survival of the organism; however, many molecular regulators of its function remain ill-defined. Here, we show that the Drosophila melanogaster bromodomain-containing protein FS(1)H is required in the fat body for normal lifespan as well as metabolic and immune homeostasis. Flies lacking fat body fs(1)h exhibit short lifespan, increased expression of immune target genes, an inability to metabolize triglyceride, and low basal AKT activity, mostly resulting from systemic defects in insulin signalling. Removal of a single copy of the AKT-responsive transcription factor foxo normalises lifespan, metabolic function, uninduced immune gene expression and AKT activity. We suggest that the promotion of systemic insulin signalling activity is a key in vivo function of fat body fs(1)h. This article has an associated First Person interview with the first author of the paper. Summary: The bromodomain-containing protein FS(1)H is required in the Drosophila fat body for normal lifespan and metabolic and immune function, largely via the insulin pathway.
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Affiliation(s)
- Jessica Sharrock
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK.,Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | | | - Jake Jacobson
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK.,Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Katrin Kierdorf
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK.,Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Marc S Dionne
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK .,Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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11
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Aughey GN, Cheetham SW, Southall TD. DamID as a versatile tool for understanding gene regulation. Development 2019; 146:146/6/dev173666. [PMID: 30877125 PMCID: PMC6451315 DOI: 10.1242/dev.173666] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 02/18/2019] [Indexed: 12/22/2022]
Abstract
The interaction of proteins and RNA with chromatin underlies the regulation of gene expression. The ability to profile easily these interactions is fundamental for understanding chromatin biology in vivo. DNA adenine methyltransferase identification (DamID) profiles genome-wide protein-DNA interactions without antibodies, fixation or protein pull-downs. Recently, DamID has been adapted for applications beyond simple assaying of protein-DNA interactions, such as for studying RNA-chromatin interactions, chromatin accessibility and long-range chromosome interactions. Here, we provide an overview of DamID and introduce improvements to the technology, discuss their applications and compare alternative methodologies. Summary: This Primer provides an overview of DNA adenine methyltransferase identification (DamID), which is used to profile genome-wide chromatin interactions, and introduces recent improvements to the technology.
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Affiliation(s)
- Gabriel N Aughey
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London, SW7 2AZ, UK
| | - Seth W Cheetham
- Mater Research Institute-University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London, SW7 2AZ, UK
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12
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Sen SQ, Chanchani S, Southall TD, Doe CQ. Neuroblast-specific open chromatin allows the temporal transcription factor, Hunchback, to bind neuroblast-specific loci. eLife 2019; 8:44036. [PMID: 30694180 PMCID: PMC6377230 DOI: 10.7554/elife.44036] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/24/2019] [Indexed: 12/12/2022] Open
Abstract
Spatial and temporal cues are required to specify neuronal diversity, but how these cues are integrated in neural progenitors remains unknown. Drosophila progenitors (neuroblasts) are a good model: they are individually identifiable with relevant spatial and temporal transcription factors known. Here we test whether spatial/temporal factors act independently or sequentially in neuroblasts. We used Targeted DamID to identify genomic binding sites of the Hunchback temporal factor in two neuroblasts (NB5-6 and NB7-4) that make different progeny. Hunchback targets were different in each neuroblast, ruling out the independent specification model. Moreover, each neuroblast had distinct open chromatin domains, which correlated with differential Hb-bound loci in each neuroblast. Importantly, the Gsb/Pax3 spatial factor, expressed in NB5-6 but not NB7-4, had genomic binding sites correlated with open chromatin in NB5-6, but not NB7-4. Our data support a model in which early-acting spatial factors like Gsb establish neuroblast-specific open chromatin domains, leading to neuroblast-specific temporal factor binding and the production of different neurons in each neuroblast lineage. The human brain is considered to be the most complicated object in the universe, but it only takes a handful of stem cells to make one. The process depends on two types of information: signals separated across space and time. Spatial cues tell a stem cell what type of cell it is going to be, while temporal cues work as molecular clocks to generate a sequence of different neurons over time. Together, these cues generate the large array of cell types in the nervous system. Each stem cell occupies its own space in the developing body and receives its own spatial cues, but they all follow the same timeline. For example, proteins called transcription factors act as molecular clocks and interact with specific genes, telling the cell when to turn them on or off. The same series of transcription factors operates in different stem cells, but they have different effects. So far, it has been unclear whether spatial and temporal signals work independently or sequentially to generate new cell types. To find out, Sen et al. studied two distinct, developing stem cells in fruit flies, which receive different spatial signals. Transcription factors only work if they are able to get to their target genes. Cells can open or close access to different genes by changing the structure of the chromatin wrapping that surrounds the genes. In the experiments, a marker was used to reveal the areas of open chromatin in each of the cells. Another marker was used to track the transcription factors. The results showed that the areas of open chromatin varied between stem cells. Moreover, although both cells used the same transcription factor called Hunchback, it targeted different genes in each stem cell. This was due to changes in the chromatin wrapping: Hunchback only acted in areas where the chromatin was open. This suggests that the spatial cues first sculpt the chromatin, making some genes easier to get to than others. Then, the same transcription factors go to the accessible gene, which will differ from one stem cell to another. These findings help us to understand how different types of brain cells develop, which may also aid us in finding a way how to engineer specific cell types. If we could turn stem cells into different types of brain cells, it might help us to treat brain diseases. This may involve giving the right spatial signal before starting the temporal cues.
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Affiliation(s)
- Sonia Q Sen
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, United States
| | - Sachin Chanchani
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, United States
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Chris Q Doe
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, United States
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13
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Cheetham SW, Gruhn WH, van den Ameele J, Krautz R, Southall TD, Kobayashi T, Surani MA, Brand AH. Targeted DamID reveals differential binding of mammalian pluripotency factors. Development 2018; 145:dev.170209. [PMID: 30185410 DOI: 10.1242/dev.170209] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 08/23/2018] [Indexed: 12/14/2022]
Abstract
The precise control of gene expression by transcription factor networks is crucial to organismal development. The predominant approach for mapping transcription factor-chromatin interactions has been chromatin immunoprecipitation (ChIP). However, ChIP requires a large number of homogeneous cells and antisera with high specificity. A second approach, DamID, has the drawback that high levels of Dam methylase are toxic. Here, we modify our targeted DamID approach (TaDa) to enable cell type-specific expression in mammalian systems, generating an inducible system (mammalian TaDa or MaTaDa) to identify genome-wide protein/DNA interactions in 100 to 1000 times fewer cells than ChIP-based approaches. We mapped the binding sites of two key pluripotency factors, OCT4 and PRDM14, in mouse embryonic stem cells, epiblast-like cells and primordial germ cell-like cells (PGCLCs). PGCLCs are an important system for elucidating primordial germ cell development in mice. We monitored PRDM14 binding during the specification of PGCLCs, identifying direct targets of PRDM14 that are key to understanding its crucial role in PGCLC development. We show that MaTaDa is a sensitive and accurate method for assessing cell type-specific transcription factor binding in limited numbers of cells.
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Affiliation(s)
- Seth W Cheetham
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Wolfram H Gruhn
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Jelle van den Ameele
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Robert Krautz
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Tony D Southall
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Toshihiro Kobayashi
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - M Azim Surani
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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Dinges N, Morin V, Kreim N, Southall TD, Roignant JY. Comprehensive Characterization of the Complex lola Locus Reveals a Novel Role in the Octopaminergic Pathway via Tyramine Beta-Hydroxylase Regulation. Cell Rep 2018; 21:2911-2925. [PMID: 29212035 DOI: 10.1016/j.celrep.2017.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 09/12/2017] [Accepted: 11/02/2017] [Indexed: 10/18/2022] Open
Abstract
Longitudinals lacking (lola) is one of the most complex genes in Drosophila melanogaster, encoding up to 20 protein isoforms that include key transcription factors involved in axonal pathfinding and neural reprogramming. Most previous studies have employed loss-of-function alleles that disrupt lola common exons, making it difficult to delineate isoform-specific functions. To overcome this issue, we have generated isoform-specific mutants for all isoforms using CRISPR/Cas9. This enabled us to study specific isoforms with respect to previously characterized roles for Lola and to demonstrate a specific function for one variant in axon guidance via activation of the microtubule-associated factor Futsch. Importantly, we also reveal a role for a second variant in preventing neurodegeneration via the positive regulation of a key enzyme of the octopaminergic pathway. Thus, our comprehensive study expands the functional repertoire of Lola functions, and it adds insights into the regulatory control of neurotransmitter expression in vivo.
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Affiliation(s)
- Nadja Dinges
- Laboratory of RNA Epigenetics, Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Violeta Morin
- Laboratory of RNA Epigenetics, Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Nastasja Kreim
- Bioinformatics Core Facility, Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Jean-Yves Roignant
- Laboratory of RNA Epigenetics, Institute of Molecular Biology (IMB), 55128 Mainz, Germany.
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15
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Aughey GN, Estacio Gomez A, Thomson J, Yin H, Southall TD. CATaDa reveals global remodelling of chromatin accessibility during stem cell differentiation in vivo. eLife 2018; 7:32341. [PMID: 29481322 PMCID: PMC5826290 DOI: 10.7554/elife.32341] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/30/2018] [Indexed: 01/09/2023] Open
Abstract
During development eukaryotic gene expression is coordinated by dynamic changes in chromatin structure. Measurements of accessible chromatin are used extensively to identify genomic regulatory elements. Whilst chromatin landscapes of pluripotent stem cells are well characterised, chromatin accessibility changes in the development of somatic lineages are not well defined. Here we show that cell-specific chromatin accessibility data can be produced via ectopic expression of E. coli Dam methylase in vivo, without the requirement for cell-sorting (CATaDa). We have profiled chromatin accessibility in individual cell-types of Drosophila neural and midgut lineages. Functional cell-type-specific enhancers were identified, as well as novel motifs enriched at different stages of development. Finally, we show global changes in the accessibility of chromatin between stem-cells and their differentiated progeny. Our results demonstrate the dynamic nature of chromatin accessibility in somatic tissues during stem cell differentiation and provide a novel approach to understanding gene regulatory mechanisms underlying development. For an embryo to successfully develop into an adult animal, specific genes must act in different types of cells. Though all the cells have the same genes encoded within their DNA, looking at the way that the DNA is packaged can indicate which parts of the DNA are important for that particular cell type. If regions of DNA are “open” one can infer that those regions are actively involved in gene regulation, whereas “closed” regions are considered less important. It is currently difficult to determine which parts of the DNA are open within an individual cell type in a complex organ, such as the brain. Existing methods require the cells to be physically isolated from the tissue, which is technically challenging. To overcome this issue, Aughey et al. have now developed a method that does not require isolation of the cells. The new technique involves using genetic engineering to introduce an enzyme called Dam into specific cell types in living fruit flies. This enzyme adds a chemical label on regions of open DNA, which can then be detected. Aughey et al. tested this technique on various cells of the developing brain and gut, and were able to see differences in the openness of DNA that corresponded to the action of genes that are important in each cell type. The data also contain trends that help to understand the role of open DNA in development. For example, mature cells were shown to overall have less open DNA than the stem cells that divide to generate them. Aughey et al. hope their new technique will be of use to other researchers working with either fruit flies or mammalian tissues. The knowledge that scientists will gain from identifying how open DNA contributes to gene regulation, in both healthy and diseased tissues, will further our understanding of human development and the biology of diseases such as cancer.
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Affiliation(s)
- Gabriel N Aughey
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Jamie Thomson
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Hang Yin
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, London, United Kingdom
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16
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Marshall OJ, Southall TD, Cheetham SW, Brand AH. Cell-type-specific profiling of protein-DNA interactions without cell isolation using targeted DamID with next-generation sequencing. Nat Protoc 2016; 11:1586-98. [PMID: 27490632 DOI: 10.1038/nprot.2016.084] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This protocol is an extension to: Nat. Protoc. 2, 1467-1478 (2007); doi:10.1038/nprot.2007.148; published online 7 June 2007The ability to profile transcription and chromatin binding in a cell-type-specific manner is a powerful aid to understanding cell-fate specification and cellular function in multicellular organisms. We recently developed targeted DamID (TaDa) to enable genome-wide, cell-type-specific profiling of DNA- and chromatin-binding proteins in vivo without cell isolation. As a protocol extension, this article describes substantial modifications to an existing protocol, and it offers additional applications. TaDa builds upon DamID, a technique for detecting genome-wide DNA-binding profiles of proteins, by coupling it with the GAL4 system in Drosophila to enable both temporal and spatial resolution. TaDa ensures that Dam-fusion proteins are expressed at very low levels, thus avoiding toxicity and potential artifacts from overexpression. The modifications to the core DamID technique presented here also increase the speed of sample processing and throughput, and adapt the method to next-generation sequencing technology. TaDa is robust, reproducible and highly sensitive. Compared with other methods for cell-type-specific profiling, the technique requires no cell-sorting, cross-linking or antisera, and binding profiles can be generated from as few as 10,000 total induced cells. By profiling the genome-wide binding of RNA polymerase II (Pol II), TaDa can also identify transcribed genes in a cell-type-specific manner. Here we describe a detailed protocol for carrying out TaDa experiments and preparing the material for next-generation sequencing. Although we developed TaDa in Drosophila, it should be easily adapted to other organisms with an inducible expression system. Once transgenic animals are obtained, the entire experimental procedure-from collecting tissue samples to generating sequencing libraries-can be accomplished within 5 d.
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Affiliation(s)
- Owen J Marshall
- The Gurdon Institute, University of Cambridge, Cambridge, UK.,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Tony D Southall
- The Gurdon Institute, University of Cambridge, Cambridge, UK.,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Seth W Cheetham
- The Gurdon Institute, University of Cambridge, Cambridge, UK.,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Andrea H Brand
- The Gurdon Institute, University of Cambridge, Cambridge, UK.,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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17
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Aughey GN, Southall TD. Dam it's good! DamID profiling of protein-DNA interactions. Wiley Interdiscip Rev Dev Biol 2015; 5:25-37. [PMID: 26383089 PMCID: PMC4737221 DOI: 10.1002/wdev.205] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/06/2015] [Accepted: 07/20/2015] [Indexed: 01/09/2023]
Abstract
The interaction of proteins with chromatin is fundamental for several essential cellular processes. During the development of an organism, genes must to be tightly regulated both temporally and spatially. This is achieved through the action of chromatin‐binding proteins such as transcription factors, histone modifiers, nucleosome remodelers, and lamins. Furthermore, protein–DNA interactions are important in the adult, where their perturbation can lead to disruption of homeostasis, metabolic dysregulation, and diseases such as cancer. Understanding the nature of these interactions is of paramount importance in almost all areas of molecular biological research. In recent years, DNA adenine methyltransferase identification (DamID) has emerged as one of the most comprehensive and versatile methods available for profiling protein–DNA interactions on a genomic scale. DamID has been used to map a variety of chromatin‐binding proteins in several model organisms and has the potential for continued adaptation and application in the field of genomic biology. WIREs Dev Biol 2016, 5:25–37. doi: 10.1002/wdev.205 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Gabriel N Aughey
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London, UK
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London, UK
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18
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McClure CD, Southall TD. Getting Down to Specifics: Profiling Gene Expression and Protein-DNA Interactions in a Cell Type-Specific Manner. Adv Genet 2015; 91:103-151. [PMID: 26410031 DOI: 10.1016/bs.adgen.2015.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The majority of multicellular organisms are comprised of an extraordinary range of cell types, with different properties and gene expression profiles. Understanding what makes each cell type unique and how their individual characteristics are attributed are key questions for both developmental and neurobiologists alike. The brain is an excellent example of the cellular diversity expressed in the majority of eukaryotes. The mouse brain comprises of approximately 75 million neurons varying in morphology, electrophysiology, and preferences for synaptic partners. A powerful process in beginning to pick apart the mechanisms that specify individual characteristics of the cell, as well as their fate, is to profile gene expression patterns, chromatin states, and transcriptional networks in a cell type-specific manner, i.e., only profiling the cells of interest in a particular tissue. Depending on the organism, the questions being investigated, and the material available, certain cell type-specific profiling methods are more suitable than others. This chapter reviews the approaches presently available for selecting and isolating specific cell types and evaluates their key features.
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Affiliation(s)
- Colin D McClure
- Department of Life Sciences, Imperial College London, London, UK
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, London, UK
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19
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Loza-Coll MA, Southall TD, Sandall SL, Brand AH, Jones DL. Regulation of Drosophila intestinal stem cell maintenance and differentiation by the transcription factor Escargot. EMBO J 2014; 33:2983-96. [PMID: 25433031 DOI: 10.15252/embj.201489050] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Tissue stem cells divide to self-renew and generate differentiated cells to maintain homeostasis. Although influenced by both intrinsic and extrinsic factors, the genetic mechanisms coordinating the decision between self-renewal and initiation of differentiation remain poorly understood. The escargot (esg) gene encodes a transcription factor that is expressed in stem cells in multiple tissues in Drosophila melanogaster, including intestinal stem cells (ISCs). Here, we demonstrate that Esg plays a pivotal role in intestinal homeostasis, maintaining the stem cell pool while influencing fate decisions through modulation of Notch activity. Loss of esg induced ISC differentiation, a decline in Notch activity in daughter enteroblasts (EB), and an increase in differentiated enteroendocrine (EE) cells. Amun, an inhibitor of Notch in other systems, was identified as a target of Esg in the intestine. Decreased expression of esg resulted in upregulation of Amun, while downregulation of Amun rescued the ectopic EE cell phenotype resulting from loss of esg. Thus, our findings provide a framework for further comparative studies addressing the conserved roles of Snail factors in coordinating self-renewal and differentiation of stem cells across tissues and species.
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Affiliation(s)
- Mariano A Loza-Coll
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, USA Department of Molecular, Cell, and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA
| | | | - Sharsti L Sandall
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Andrea H Brand
- The Gurdon Institute University of Cambridge, Cambridge, UK
| | - D Leanne Jones
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, USA Department of Molecular, Cell, and Developmental Biology, University of California Los Angeles, Los Angeles, CA, USA Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA
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20
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Korzelius J, Naumann SK, Loza-Coll MA, Chan JS, Dutta D, Oberheim J, Gläßer C, Southall TD, Brand AH, Jones DL, Edgar BA. Escargot maintains stemness and suppresses differentiation in Drosophila intestinal stem cells. EMBO J 2014; 33:2967-82. [PMID: 25298397 PMCID: PMC4282643 DOI: 10.15252/embj.201489072] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Snail family transcription factors are expressed in various stem cell types, but their function in maintaining stem cell identity is unclear. In the adult Drosophila midgut, the Snail homolog Esg is expressed in intestinal stem cells (ISCs) and their transient undifferentiated daughters, termed enteroblasts (EB). We demonstrate here that loss of esg in these progenitor cells causes their rapid differentiation into enterocytes (EC) or entero-endocrine cells (EE). Conversely, forced expression of Esg in intestinal progenitor cells blocks differentiation, locking ISCs in a stem cell state. Cell type-specific transcriptome analysis combined with Dam-ID binding studies identified Esg as a major repressor of differentiation genes in stem and progenitor cells. One critical target of Esg was found to be the POU-domain transcription factor, Pdm1, which is normally expressed specifically in differentiated ECs. Ectopic expression of Pdm1 in progenitor cells was sufficient to drive their differentiation into ECs. Hence, Esg is a critical stem cell determinant that maintains stemness by repressing differentiation-promoting factors, such as Pdm1.
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Affiliation(s)
- Jerome Korzelius
- DKFZ/ZMBH Alliance, University of Heidelberg, Heidelberg, Germany
| | - Svenja K Naumann
- DKFZ/ZMBH Alliance, University of Heidelberg, Heidelberg, Germany
| | - Mariano A Loza-Coll
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, USA Department of Molecular, Cell, and Developmental Biology, University of California-Los Angeles, Los Angeles, CA, USA
| | - Jessica Sk Chan
- DKFZ/ZMBH Alliance, University of Heidelberg, Heidelberg, Germany
| | - Devanjali Dutta
- DKFZ/ZMBH Alliance, University of Heidelberg, Heidelberg, Germany
| | - Jessica Oberheim
- DKFZ/ZMBH Alliance, University of Heidelberg, Heidelberg, Germany
| | - Christine Gläßer
- DKFZ/ZMBH Alliance, University of Heidelberg, Heidelberg, Germany
| | - Tony D Southall
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - D Leanne Jones
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, USA Department of Molecular, Cell, and Developmental Biology, University of California-Los Angeles, Los Angeles, CA, USA
| | - Bruce A Edgar
- DKFZ/ZMBH Alliance, University of Heidelberg, Heidelberg, Germany
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21
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Southall TD, Gold KS, Egger B, Davidson CM, Caygill EE, Marshall OJ, Brand AH. Cell-type-specific profiling of gene expression and chromatin binding without cell isolation: assaying RNA Pol II occupancy in neural stem cells. Dev Cell 2013; 26:101-12. [PMID: 23792147 PMCID: PMC3714590 DOI: 10.1016/j.devcel.2013.05.020] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 03/20/2013] [Accepted: 05/24/2013] [Indexed: 12/20/2022]
Abstract
Cell-type-specific transcriptional profiling often requires the isolation of specific cell types from complex tissues. We have developed “TaDa,” a technique that enables cell-specific profiling without cell isolation. TaDa permits genome-wide profiling of DNA- or chromatin-binding proteins without cell sorting, fixation, or affinity purification. The method is simple, sensitive, highly reproducible, and transferable to any model system. We show that TaDa can be used to identify transcribed genes in a cell-type-specific manner with considerable temporal precision, enabling the identification of differential gene expression between neuroblasts and the neuroepithelial cells from which they derive. We profile the genome-wide binding of RNA polymerase II in these adjacent, clonally related stem cells within intact Drosophila brains. Our data reveal expression of specific metabolic genes in neuroepithelial cells, but not in neuroblasts, and highlight gene regulatory networks that may pattern neural stem cell fates. TaDa is a method for cell-type-specific profiling of chromatin binding proteins TaDa does not require cell sorting, fixation, or affinity purification This is a highly sensitive and robust technique for transcriptional profiling We report differential RNA Pol II binding in clonally related stem cells
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Affiliation(s)
- Tony D Southall
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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22
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Wolfram V, Southall TD, Brand AH, Baines RA. The LIM-homeodomain protein islet dictates motor neuron electrical properties by regulating K(+) channel expression. Neuron 2012; 75:663-74. [PMID: 22920257 PMCID: PMC3427859 DOI: 10.1016/j.neuron.2012.06.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2012] [Indexed: 11/24/2022]
Abstract
Neuron electrical properties are critical to function and generally subtype specific, as are patterns of axonal and dendritic projections. Specification of motoneuron morphology and axon pathfinding has been studied extensively, implicating the combinatorial action of Lim-homeodomain transcription factors. However, the specification of electrical properties is not understood. Here, we address the key issues of whether the same transcription factors that specify morphology also determine subtype specific electrical properties. We show that Drosophila motoneuron subtypes express different K+ currents and that these are regulated by the conserved Lim-homeodomain transcription factor Islet. Specifically, Islet is sufficient to repress a Shaker-mediated A-type K+ current, most likely due to a direct transcriptional effect. A reduction in Shaker increases the frequency of action potential firing. Our results demonstrate the deterministic role of Islet on the excitability patterns characteristic of motoneuron subtypes.
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Bardin AJ, Perdigoto CN, Southall TD, Brand AH, Schweisguth F. Transcriptional control of stem cell maintenance in the Drosophila intestine. Development 2010; 137:705-14. [PMID: 20147375 DOI: 10.1242/dev.039404] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Adult stem cells maintain tissue homeostasis by controlling the proper balance of stem cell self-renewal and differentiation. The adult midgut of Drosophila contains multipotent intestinal stem cells (ISCs) that self-renew and produce differentiated progeny. Control of ISC identity and maintenance is poorly understood. Here we find that transcriptional repression of Notch target genes by a Hairless-Suppressor of Hairless complex is required for ISC maintenance, and identify genes of the Enhancer of split complex [E(spl)-C] as the major targets of this repression. In addition, we find that the bHLH transcription factor Daughterless is essential to maintain ISC identity and that bHLH binding sites promote ISC-specific enhancer activity. We propose that Daughterless-dependent bHLH activity is important for the ISC fate and that E(spl)-C factors inhibit this activity to promote differentiation.
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Bardin AJ, Perdigoto CN, Southall TD, Brand AH, Schweisguth F. Transcriptional control of stem cell maintenance in the Drosophila intestine. J Cell Sci 2010. [DOI: 10.1242/jcs.069401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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25
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Southall TD, Egger B, Gold KS, Brand AH. Regulation of self-renewal and differentiation in the Drosophila nervous system. Cold Spring Harb Symp Quant Biol 2009; 73:523-8. [PMID: 19150959 DOI: 10.1101/sqb.2008.73.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Stem cells can divide symmetrically to generate two similar daughter cells and expand the stem cell pool or asymmetrically to self-renew and generate differentiating daughter cells. The proper balance between symmetric and asymmetric division is critical for the generation and subsequent repair of tissues. Furthermore, unregulated stem cell division has been shown to result in tumorous overgrowth. The Drosophila nervous system has proved to be a fruitful model system for studying the biology of neural stem cell division and uncovering the molecular mechanisms that, when disrupted, can lead to tumor formation. We are using the Drosophila embryonic and larval nervous systems as models to study the regulation of symmetric and asymmetric stem cell division.
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Affiliation(s)
- T D Southall
- The Gurdon Institute and Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 1QN, United Kingdom
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Abstract
INTRODUCTIONThe GAL4 system is a method for ectopic gene expression that allows the selective activation of any cloned gene in a wide variety of tissue- and cell-specific patterns. This protocol describes the generation of driver and reporter lines for use with the GAL4 system in Drosophila. A promoter-GAL4 fusion is constructed using a P-element transformable vector, and a GAL4-responsive target gene is created via generation of an upstream activation sequence (UAS)-reporter construct. An alternative strategy for integration using the phiC31 system is also provided. Transformant lines are generated using standard procedures for microinjection.
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Affiliation(s)
- Tony D Southall
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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27
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Abstract
INTRODUCTIONThe generation of gain-of-function phenotypes by ectopic expression of known genes provides a powerful complement to the genetic approach, in which genes are studied or identified through mutations that generally reduce or eliminate gene function. The GAL4 system is a method for ectopic gene expression that allows the selective activation of any cloned gene in a wide variety of tissue- and cell-specific patterns. A key advantage of the system is the separation of the GAL4 protein from its target gene in distinct transgenic lines, which ensures that the target gene is silent until the introduction of GAL4. Recent modifications and adaptations of the GAL4 system to make the system inducible have further expanded its scope, enabling greater temporal control over the activity of GAL4. There are now large resources for the community, including thousands of GAL4 lines and a wide selection of reporter lines. Here we present an overview of the GAL4 system, highlighting recent developments and discussing methods for generating and analyzing transgenic flies for GAL4-mediated ectopic expression.
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Affiliation(s)
- Tony D Southall
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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28
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Abstract
The correct control of gene expression is essential for the proper development of organisms. Abnormal expression of genes can lead to cancerous growth and certain diseases. To understand how gene expression is controlled on a genome-wide scale, methods for assaying transcription factor binding sites are required. There are two prevailing techniques for mapping protein-chromatin interactions, ChIP (chromatin immunoprecipitation) and DamID (DNA adenine methyltransferase identification). Both of these methods, when combined with microarray technology, can provide powerful insights into transcription factor function, higher order chromatin structure and gene regulatory networks. In vivo chromatin profiling studies are now being performed on model organisms, targeting specific tissues to help generate more accurate maps of protein-DNA interactions.
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Affiliation(s)
- Tony D Southall
- The Gurdon Institute, Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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29
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Choksi SP, Southall TD, Bossing T, Edoff K, de Wit E, Fischer BE, van Steensel B, Micklem G, Brand AH. Prospero Acts as a Binary Switch between Self-Renewal and Differentiation in Drosophila Neural Stem Cells. Dev Cell 2006; 11:775-89. [PMID: 17141154 DOI: 10.1016/j.devcel.2006.09.015] [Citation(s) in RCA: 313] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 07/26/2006] [Accepted: 09/19/2006] [Indexed: 12/23/2022]
Abstract
Stem cells have the remarkable ability to give rise to both self-renewing and differentiating daughter cells. Drosophila neural stem cells segregate cell-fate determinants from the self-renewing cell to the differentiating daughter at each division. Here, we show that one such determinant, the homeodomain transcription factor Prospero, regulates the choice between stem cell self-renewal and differentiation. We have identified the in vivo targets of Prospero throughout the entire genome. We show that Prospero represses genes required for self-renewal, such as stem cell fate genes and cell-cycle genes. Surprisingly, Prospero is also required to activate genes for terminal differentiation. We further show that in the absence of Prospero, differentiating daughters revert to a stem cell-like fate: they express markers of self-renewal, exhibit increased proliferation, and fail to differentiate. These results define a blueprint for the transition from stem cell self-renewal to terminal differentiation.
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Affiliation(s)
- Semil P Choksi
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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Pym ECG, Southall TD, Mee CJ, Brand AH, Baines RA. The homeobox transcription factor Even-skipped regulates acquisition of electrical properties in Drosophila neurons. Neural Dev 2006; 1:3. [PMID: 17147779 PMCID: PMC1679800 DOI: 10.1186/1749-8104-1-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 11/16/2006] [Indexed: 11/28/2022] Open
Abstract
Background While developmental processes such as axon pathfinding and synapse formation have been characterized in detail, comparatively less is known of the intrinsic developmental mechanisms that regulate transcription of ion channel genes in embryonic neurons. Early decisions, including motoneuron axon targeting, are orchestrated by a cohort of transcription factors that act together in a combinatorial manner. These transcription factors include Even-skipped (Eve), islet and Lim3. The perdurance of these factors in late embryonic neurons is, however, indicative that they might also regulate additional aspects of neuron development, including the acquisition of electrical properties. Results To test the hypothesis that a combinatorial code transcription factor is also able to influence the acquisition of electrical properties in embryonic neurons we utilized the molecular genetics of Drosophila to manipulate the expression of Eve in identified motoneurons. We show that increasing expression of this transcription factor, in two Eve-positive motoneurons (aCC and RP2), is indeed sufficient to affect the electrical properties of these neurons in early first instar larvae. Specifically, we observed a decrease in both the fast K+ conductance (IKfast) and amplitude of quantal cholinergic synaptic input. We used charybdotoxin to pharmacologically separate the individual components of IKfast to show that increased Eve specifically down regulates the Slowpoke (a BK Ca2+-gated potassium channel), but not Shal, component of this current. Identification of target genes for Eve, using DNA adenine methyltransferase identification, revealed strong binding sites in slowpoke and nAcRα-96Aa (a nicotinic acetylcholine receptor subunit). Verification using real-time PCR shows that pan-neuronal expression of eve is sufficient to repress transcripts for both slo and nAcRα-96Aa. Conclusion Taken together, our findings demonstrate, for the first time, that Eve is sufficient to regulate both voltage- and ligand-gated currents in motoneurons, extending its known repertoire of action beyond its already characterized role in axon guidance. Our data are also consistent with a common developmental program that utilizes a defined set of transcription factors to determine both morphological and functional neuronal properties.
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Affiliation(s)
- Edward CG Pym
- Neuroscience Group, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Tony D Southall
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Christopher J Mee
- Neuroscience Group, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Richard A Baines
- Neuroscience Group, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK
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Du J, Kean L, Allan AK, Southall TD, Davies SA, McInerny CJ, Dow JAT. TheSzAmutations of the B subunit of theDrosophilavacuolar H+ ATPase identify conserved residues essential for function in fly and yeast. J Cell Sci 2006; 119:2542-51. [PMID: 16735441 DOI: 10.1242/jcs.02983] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
V-ATPases play multiple roles in eukaryotes: in Drosophila, null mutations are recessive lethal. Here, mutations underlying five extant lethal alleles of vha55, encoding the B subunit, were identified, including a premature termination codon and two mutations very close to residues thought to participate in the catalytic site of the enzyme. Lethality of these alleles could be reverted by transformation of flies with a wild type vha55::GFP fusion, confirming that the lethal phenotype described for these alleles was due to defects in V-ATPase function. The chimeric protein was correctly localised to the apical domain of the Malpighian (renal) tubule, and restored fluid transport function to wild-type levels. No dominant-negative phenotype was apparent in heterozygotes. When the vha55::GFP fusion was driven ubiquitously, fluorescent protein was only detectable in tissues known to contain high levels of V-ATPase, suggesting that vha55 requires stoichometric co-expression of other subunits to be stable. Yeast (Saccharomyces cerevisiae) deleted for the corresponding gene (Δvma2) demonstrated a pH-sensitive growth phenotype that was rescued by the vha55::GFP construct. Δvma2 yeast could not be rescued with fly cDNAs encoding any of the mutant vha55 alleles, confirming the functional significance of the mutated residues. In yeast, bafilomycin-sensitive ATPase activity and growth rate correlated with the ability of different constructs to rescue the pH-sensitive conditional-lethal phenotype. These classical Drosophila mutants thus identify residues that are essential for function in organisms with wide phylogenetic separation.
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Affiliation(s)
- Juan Du
- Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, G11 6NU, UK
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Southall TD, Terhzaz S, Cabrero P, Chintapalli VR, Evans JM, Dow JAT, Davies SA. Novel subcellular locations and functions for secretory pathway Ca2+/Mn2+-ATPases. Physiol Genomics 2006; 26:35-45. [PMID: 16609144 DOI: 10.1152/physiolgenomics.00038.2006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Secretory pathway Ca2+/Mn2+-ATPases (SPCAs) are important for maintenance of cellular Ca2+and Mn2+homeostasis, and, to date, all SPCAs have been found to localize to the Golgi apparatus. The single Drosophila SPCA gene ( SPoCk) was identified by an in silico screen for novel Ca2+-ATPases. It encoded three SPoCk isoforms with novel, distinct subcellular specificities in the endoplasmic reticulum (ER) and peroxisomes in addition to the Golgi. Furthermore, expression of the peroxisome-associated SPoCk isoform was sexually dimorphic. Overexpression of organelle-specific SPoCk isoforms impacted on cytosolic Ca2+handling in both cultured Drosophila cells and a transporting epithelium, the Drosophila Malpighian (renal) tubule. Specifically, the ER isoform impacted on inositol ( 1 , 4 , 5 )-trisphosphate-mediated Ca2+signaling and the Golgi isoform impacted on diuresis, whereas the peroxisome isoform colocalized with Ca2+“spherites” and impacted on calcium storage and transport. Interfering RNA directed against the common exons of the three SPoCk isoforms resulted in aberrant Ca2+signaling and abolished neuropeptide-stimulated diuresis by the tubule. SPoCk thus contributed to both of the contrasting requirements for Ca2+in transporting epithelia: to transport or store Ca2+in bulk without compromising its use as a signal.
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Affiliation(s)
- Tony D Southall
- Division of Molecular Genetics, Anderson College Complex, University of Glasgow, Glasgow, United Kingdom
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Terhzaz S, Southall TD, Lilley KS, Kean L, Allan AK, Davies SA, Dow JAT. Differential gel electrophoresis and transgenic mitochondrial calcium reporters demonstrate spatiotemporal filtering in calcium control of mitochondria. J Biol Chem 2006; 281:18849-58. [PMID: 16670086 DOI: 10.1074/jbc.m603002200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondria must adjust both their intracellular location and their metabolism in order to balance their output to the needs of the cell. Here we show by the proteomic technique of time series difference gel electrophoresis that a major result of neuroendocrine stimulation of the Drosophila renal tubule is an extensive remodeling of the mitochondrial matrix. By generating Drosophila that were transgenic for both luminescent and fluorescent mitochondrial calcium reporters, it was shown that mitochondrial calcium tracked the slow (minutes) but not the rapid (<1 s) changes in cytoplasmic calcium and that this resulted in both increased mitochondrial membrane polarization and elevated cellular ATP levels. The selective V-ATPase inhibitor, bafilomycin, further enhanced ATP levels, suggesting that the apical plasma membrane V-ATPase is a major consumer of ATP. Both the mitochondrial calcium signal and the increase in ATP were abolished by the mitochondrial calcium uniporter blocker Ru360. By using both mitochondrial calcium imaging and the potential sensing dye JC-1, the apical mitochondria of principal cells were found to be selectively responsive to neuropeptide signaling. As the ultimate target is the V-ATPase in the apical plasma membrane, this selective activation of mitochondria is clearly adaptive. The results highlight the dynamic nature and both spatial and temporal heterogeneity of calcium signaling possible in differentiated, organotypic cells and provide a new model for neuroendocrine control of V-ATPase.
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Affiliation(s)
- Selim Terhzaz
- Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Glasgow G11 6NU, Scotland, UK
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MacPherson MR, Pollock VP, Kean L, Southall TD, Giannakou ME, Broderick KE, Dow JAT, Hardie RC, Davies SA. Transient receptor potential-like channels are essential for calcium signaling and fluid transport in a Drosophila epithelium. Genetics 2005; 169:1541-52. [PMID: 15695363 PMCID: PMC1449567 DOI: 10.1534/genetics.104.035139] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Accepted: 12/09/2004] [Indexed: 11/18/2022] Open
Abstract
Calcium signaling is an important mediator of neuropeptide-stimulated fluid transport by Drosophila Malpighian (renal) tubules. We demonstrate the first epithelial role, in vivo, for members of the TRP family of calcium channels. RT-PCR revealed expression of trp, trpl, and trpgamma in tubules. Use of antipeptide polyclonal antibodies for TRP, TRPL, and TRPgamma showed expression of all three channels in type 1 (principal) cells in the tubule main segment. Neuropeptide (CAP(2b))-stimulated fluid transport rates were significantly reduced in tubules from the trpl(302) mutant and the trpl;trp double mutant, trpl(302);trp(343). However, a trp null, trp(343), had no impact on stimulated fluid transport. Measurement of cytosolic calcium concentrations ([Ca(2+)](i)) in tubule principal cells using an aequorin transgene in trp and trpl mutants showed a reduction in calcium responses in trpl(302). Western blotting of tubule preparations from trp and trpl mutants revealed a correlation between TRPL levels and CAP(2b)-stimulated fluid transport and calcium signaling. Rescue of trpl(302) with a trpl transgene under heat-shock control resulted in a stimulated fluid transport phenotype that was indistinguishable from wild-type tubules. Furthermore, restoration of normal stimulated rates of fluid transport by rescue of trpl(302) was not compromised by introduction of the trp null, trp(343). Thus, in an epithelial context, TRPL is sufficient for wild-type responses. Finally, a scaffolding component of the TRPL/TRP-signaling complex, INAD, is not expressed in tubules, suggesting that inaD is not essential for TRPL/TRP function in Drosophila tubules.
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Torrie LS, Radford JC, Southall TD, Kean L, Dinsmore AJ, Davies SA, Dow JAT. Resolution of the insect ouabain paradox. Proc Natl Acad Sci U S A 2004; 101:13689-93. [PMID: 15347816 PMCID: PMC518814 DOI: 10.1073/pnas.0403087101] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Indexed: 11/18/2022] Open
Abstract
Many insects are highly resistant to plant toxins, such as the cardiac glycoside ouabain. How can the epithelia that must handle such toxins, also be refractory to them? In Drosophila, the Malpighian (renal) tubule contains large amounts of Na(+),K(+) ATPase that is known biochemically to be exquisitely sensitive to ouabain, yet the intact tissue is almost unaffected by even extraordinary concentrations. The explanation is that the tubules are protected by an active ouabain transport system, colocated with the Na(+),K(+) ATPase, thus preventing ouabain from reaching inhibitory concentrations within the basolateral infoldings of principal cells. These data show that the Na(+),K(+) ATPase, previously thought to be unimportant, may be as vital in insect tissues as in vertebrates, but can be cryptic to conventional pharmacology.
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Affiliation(s)
- Leah S Torrie
- Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, Scotland, United Kingdom
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