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Valzania L, Alami A, Léopold P. A temporal allocation of amino acid resources ensures fitness and body allometry in Drosophila. Dev Cell 2024; 59:2277-2286.e6. [PMID: 38851190 DOI: 10.1016/j.devcel.2024.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 03/29/2024] [Accepted: 05/15/2024] [Indexed: 06/10/2024]
Abstract
Organisms have evolved strategies to store resources and overcome periods of low or no nutrient access, including transient shortages or longer non-feeding developmental transitions. Holometabolous insects like Drosophila represent an attractive model to study resource allocation during development because they alternate feeding and non-feeding periods. Amino acids are essential components for tissue growth and renewal, but the strategies used for their storage remain largely unexplored. Here, we characterize the molecular mechanisms for the temporal production, accumulation, and use of specific storage proteins called hexamerins, and demonstrate their role in ensuring tissue formation and adult fitness. Moreover, we show that preventing hexamerin stores enhances the growth of early-developing organs while compromising the emergence of late-forming ones, consequently altering body allometry.
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Affiliation(s)
- Luca Valzania
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 26 rue d'Ulm, 75005 Paris, France.
| | - Aya Alami
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 26 rue d'Ulm, 75005 Paris, France
| | - Pierre Léopold
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 26 rue d'Ulm, 75005 Paris, France.
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2
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Bernard EIM, Towler BP, Rogoyski OM, Newbury SF. Characterisation of the in-vivo miRNA landscape in Drosophila ribonuclease mutants reveals Pacman-mediated regulation of the highly conserved let-7 cluster during apoptotic processes. Front Genet 2024; 15:1272689. [PMID: 38444757 PMCID: PMC10912645 DOI: 10.3389/fgene.2024.1272689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 01/24/2024] [Indexed: 03/07/2024] Open
Abstract
The control of gene expression is a fundamental process essential for correct development and to maintain homeostasis. Many post-transcriptional mechanisms exist to maintain the correct levels of each RNA transcript within the cell. Controlled and targeted cytoplasmic RNA degradation is one such mechanism with the 5'-3' exoribonuclease Pacman (XRN1) and the 3'-5' exoribonuclease Dis3L2 playing crucial roles. Loss of function mutations in either Pacman or Dis3L2 have been demonstrated to result in distinct phenotypes, and both have been implicated in human disease. One mechanism by which gene expression is controlled is through the function of miRNAs which have been shown to be crucial for the control of almost all cellular processes. Although the biogenesis and mechanisms of action of miRNAs have been comprehensively studied, the mechanisms regulating their own turnover are not well understood. Here we characterise the miRNA landscape in a natural developing tissue, the Drosophila melanogaster wing imaginal disc, and assess the importance of Pacman and Dis3L2 on the abundance of miRNAs. We reveal a complex landscape of miRNA expression and show that whilst a null mutation in dis3L2 has a minimal effect on the miRNA expression profile, loss of Pacman has a profound effect with a third of all detected miRNAs demonstrating Pacman sensitivity. We also reveal a role for Pacman in regulating the highly conserved let-7 cluster (containing miR-100, let-7 and miR-125) and present a genetic model outlining a positive feedback loop regulated by Pacman which enhances our understanding of the apoptotic phenotype observed in Pacman mutants.
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Affiliation(s)
- Elisa I. M. Bernard
- Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | - Benjamin P. Towler
- Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
- School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Oliver M. Rogoyski
- Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | - Sarah F. Newbury
- Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
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3
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Bardhan S, Bhargava N, Dighe S, Vats N, Naganathan SR. Emergence of a left-right symmetric body plan in vertebrate embryos. Curr Top Dev Biol 2024; 159:310-342. [PMID: 38729680 DOI: 10.1016/bs.ctdb.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
External bilateral symmetry is a prevalent feature in vertebrates, which emerges during early embryonic development. To begin with, vertebrate embryos are largely radially symmetric before transitioning to bilaterally symmetry, after which, morphogenesis of various bilateral tissues (e.g somites, otic vesicle, limb bud), and structures (e.g palate, jaw) ensue. While a significant amount of work has probed the mechanisms behind symmetry breaking in the left-right axis leading to asymmetric positioning of internal organs, little is known about how bilateral tissues emerge at the same time with the same shape and size and at the same position on the two sides of the embryo. By discussing emergence of symmetry in many bilateral tissues and structures across vertebrate model systems, we highlight that understanding symmetry establishment is largely an open field, which will provide deep insights into fundamental problems in developmental biology for decades to come.
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Affiliation(s)
- Siddhartha Bardhan
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Nandini Bhargava
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Swarali Dighe
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Neha Vats
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Sundar Ram Naganathan
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
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Milán M. Organogenesis: Cell death matters in size and shape regulation. Curr Biol 2024; 34:R62-R64. [PMID: 38262361 DOI: 10.1016/j.cub.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Anisotropic growth and large-scale morphogenetic movements contribute to the final size and shape of the adult Drosophila wing. A new study unravels an unexpected contribution of cell death, which follows a spatial and temporal pattern, to the growth of the wing and the acquisition of its elongated shape.
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Affiliation(s)
- Marco Milán
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain.
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5
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Matamoro-Vidal A, Cumming T, Davidović A, Levillayer F, Levayer R. Patterned apoptosis has an instructive role for local growth and tissue shape regulation in a fast-growing epithelium. Curr Biol 2024; 34:376-388.e7. [PMID: 38215743 PMCID: PMC10808510 DOI: 10.1016/j.cub.2023.12.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/13/2023] [Accepted: 12/11/2023] [Indexed: 01/14/2024]
Abstract
What regulates organ size and shape remains one fundamental mystery of modern biology. Research in this area has primarily focused on deciphering the regulation in time and space of growth and cell division, while the contribution of cell death has been overall neglected. This includes studies of the Drosophila wing, one of the best-characterized systems for the study of growth and patterning, undergoing massive growth during larval stage and important morphogenetic remodeling during pupal stage. So far, it has been assumed that cell death was relatively neglectable in this tissue both during larval stage and pupal stage, and as a result, the pattern of growth was usually attributed to the distribution of cell division. Here, using systematic mapping and registration combined with quantitative assessment of clone size and disappearance as well as live imaging, we outline a persistent pattern of cell death and clone elimination emerging in the larval wing disc and persisting during pupal wing morphogenesis. Local variation of cell death is associated with local variation of clone size, pointing to an impact of cell death on local growth that is not fully compensated by proliferation. Using morphometric analyses of adult wing shape and genetic perturbations, we provide evidence that patterned death locally and globally affects adult wing shape and size. This study describes a roadmap for precise assessment of the contribution of cell death to tissue shape and outlines an important instructive role of cell death in modulating quantitatively local growth and morphogenesis of a fast-growing tissue.
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Affiliation(s)
- Alexis Matamoro-Vidal
- Department of Developmental and Stem Cell Biology, Institut Pasteur, CNRS UMR 3738, Université Paris Cité, Cell Death and Epithelial Homeostasis Unit, 75015 Paris, France
| | - Tom Cumming
- Department of Developmental and Stem Cell Biology, Institut Pasteur, CNRS UMR 3738, Université Paris Cité, Cell Death and Epithelial Homeostasis Unit, 75015 Paris, France; PPU program Institut Pasteur, Sorbonne Université, Collège Doctoral, 75005 Paris, France
| | - Anđela Davidović
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, 75015 Paris, France
| | - Florence Levillayer
- Department of Developmental and Stem Cell Biology, Institut Pasteur, CNRS UMR 3738, Université Paris Cité, Cell Death and Epithelial Homeostasis Unit, 75015 Paris, France
| | - Romain Levayer
- Department of Developmental and Stem Cell Biology, Institut Pasteur, CNRS UMR 3738, Université Paris Cité, Cell Death and Epithelial Homeostasis Unit, 75015 Paris, France.
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Truman JW, Riddiford LM, Konopová B, Nouzova M, Noriega FG, Herko M. The embryonic role of juvenile hormone in the firebrat, Thermobia domestica, reveals its function before its involvement in metamorphosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.06.561279. [PMID: 37873170 PMCID: PMC10592639 DOI: 10.1101/2023.10.06.561279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
To gain insights into how juvenile hormone (JH) came to regulate insect metamorphosis, we studied its function in the ametabolous firebrat, Thermobia domestica. Highest levels of JH occur during late embryogenesis, with only low levels thereafter. Loss-of-function and gain-of-function experiments show that JH acts on embryonic tissues to suppress morphogenesis and cell determination and to promote their terminal differentiation. Similar embryonic actions of JH on hemimetabolous insects with short germ band embryos indicate that JH's embryonic role preceded its derived function as the postembryonic regulator of metamorphosis. The postembryonic expansion of JH function likely followed the evolution of flight. Archaic flying insects were considered to lack metamorphosis because tiny, movable wings were evident on the thoraces of young juveniles and their positive allometric growth eventually allowed them to support flight in late juveniles. Like in Thermobia, we assume that these juveniles lacked JH. However, a postembryonic reappearance of JH during wing morphogenesis in the young juvenile likely redirected wing development to make a wing pad rather than a wing. Maintenance of JH then allowed wing pad growth and its disappearance in the mature juvenile then allowed wing differentiation. Subsequent modification of JH action for hemi- and holometabolous lifestyles are discussed.
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Affiliation(s)
- James W. Truman
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA
- Department of Biology, University of Washington, Seattle, WA USA
| | - Lynn M. Riddiford
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA
- Department of Biology, University of Washington, Seattle, WA USA
| | - Barbora Konopová
- Department of Zoology, Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Marcela Nouzova
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Fernando G. Noriega
- Department of Biological Sciences and BSI, Florida International University, FL ,USA
- Department of Parasitology, Faculty of Science, University of South Bohemia, Ceské Budejovice, Czech Republic
| | - Michelle Herko
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA
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Perez-Mockus G, Cocconi L, Alexandre C, Aerne B, Salbreux G, Vincent JP. The Drosophila ecdysone receptor promotes or suppresses proliferation according to ligand level. Dev Cell 2023; 58:2128-2139.e4. [PMID: 37769663 PMCID: PMC7615657 DOI: 10.1016/j.devcel.2023.08.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 07/20/2023] [Accepted: 08/30/2023] [Indexed: 10/03/2023]
Abstract
The steroid hormone 20-hydroxy-ecdysone (20E) promotes proliferation in Drosophila wing precursors at low titer but triggers proliferation arrest at high doses. Remarkably, wing precursors proliferate normally in the complete absence of the 20E receptor, suggesting that low-level 20E promotes proliferation by overriding the default anti-proliferative activity of the receptor. By contrast, 20E needs its receptor to arrest proliferation. Dose-response RNA sequencing (RNA-seq) analysis of ex vivo cultured wing precursors identifies genes that are quantitatively activated by 20E across the physiological range, likely comprising positive modulators of proliferation and other genes that are only activated at high doses. We suggest that some of these "high-threshold" genes dominantly suppress the activity of the pro-proliferation genes. We then show mathematically and with synthetic reporters that combinations of basic regulatory elements can recapitulate the behavior of both types of target genes. Thus, a relatively simple genetic circuit can account for the bimodal activity of this hormone.
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Affiliation(s)
| | - Luca Cocconi
- The Francis Crick Institute, London NW1 1AT, UK.
| | | | | | - Guillaume Salbreux
- The Francis Crick Institute, London NW1 1AT, UK; Department of Genetics and Evolution, University of Geneva, Quai Ernest-Ansermet 30, 1205 Geneva, Switzerland.
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