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Bai Y, Lv YN, Zeng M, Yan ZY, Huang DY, Wen JZ, Lu HN, Zhang PY, Wang YF, Ban N, Yuan DW, Li S, Luan YX. E93 is indispensable for reproduction in ametabolous and hemimetabolous insects. Development 2024; 151:dev202518. [PMID: 38646855 DOI: 10.1242/dev.202518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 04/15/2024] [Indexed: 04/23/2024]
Abstract
Ecdysone-induced protein 93 (E93), known as the 'adult-specifier' transcription factor in insects, triggers metamorphosis in both hemimetabolous and holometabolous insects. Although E93 is conserved in ametabolous insects, its spatiotemporal expression and physiological function remain poorly understood. In this study, we first discover that, in the ametabolous firebrat Thermobia domestica, the previtellogenic ovary exhibits cyclically high E93 expression, and E93 mRNA is broadly distributed in previtellogenic ovarioles. E93 homozygous mutant females of T. domestica exhibit severe fecundity deficiency due to impaired previtellogenic development of the ovarian follicles, likely because E93 induces the expression of genes involved in ECM (extracellular matrix)-receptor interactions during previtellogenesis. Moreover, we reveal that in the hemimetabolous cockroach Blattella germanica, E93 similarly promotes previtellogenic ovarian development. In addition, E93 is also essential for vitellogenesis that is necessary to guarantee ovarian maturation and promotes the vitellogenesis-previtellogenesis switch in the fat body of adult female cockroaches. Our findings deepen the understanding of the roles of E93 in controlling reproduction in insects, and of E93 expression and functional evolution, which are proposed to have made crucial contributions to the origin of insect metamorphosis.
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Affiliation(s)
- Yu Bai
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
- Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou 514000, China
| | - Ya-Nan Lv
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Mei Zeng
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Zi-Yu Yan
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Dan-Yan Huang
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Jia-Zhen Wen
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Hu-Na Lu
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Pei-Yan Zhang
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Yi-Fan Wang
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Ning Ban
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Dong-Wei Yuan
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
| | - Sheng Li
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
- Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou 514000, China
| | - Yun-Xia Luan
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510000, China
- Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou 514000, China
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Campli G, Volovych O, Kim K, Veldsman WP, Drage HB, Sheizaf I, Lynch S, Chipman AD, Daley AC, Robinson-Rechavi M, Waterhouse RM. The moulting arthropod: a complete genetic toolkit review. Biol Rev Camb Philos Soc 2024. [PMID: 39039636 DOI: 10.1111/brv.13123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 07/09/2024] [Accepted: 07/12/2024] [Indexed: 07/24/2024]
Abstract
Exoskeletons are a defining character of all arthropods that provide physical support for their segmented bodies and appendages as well as protection from the environment and predation. This ubiquitous yet evolutionarily variable feature has been instrumental in facilitating the adoption of a variety of lifestyles and the exploitation of ecological niches across all environments. Throughout the radiation that produced the more than one million described modern species, adaptability afforded by segmentation and exoskeletons has led to a diversity that is unrivalled amongst animals. However, because of the limited extensibility of exoskeleton chitin and cuticle components, they must be periodically shed and replaced with new larger ones, notably to accommodate the growing individuals encased within. Therefore, arthropods grow discontinuously by undergoing periodic moulting events, which follow a series of steps from the preparatory pre-moult phase to ecdysis itself and post-moult maturation of new exoskeletons. Each event represents a particularly vulnerable period in an arthropod's life cycle, so processes must be tightly regulated and meticulously executed to ensure successful transitions for normal growth and development. Decades of research in representative arthropods provide a foundation of understanding of the mechanisms involved. Building on this, studies continue to develop and test hypotheses on the presence and function of molecular components, including neuropeptides, hormones, and receptors, as well as the so-called early, late, and fate genes, across arthropod diversity. Here, we review the literature to develop a comprehensive overview of the status of accumulated knowledge of the genetic toolkit governing arthropod moulting. From biosynthesis and regulation of ecdysteroid and sesquiterpenoid hormones, to factors involved in hormonal stimulation responses and exoskeleton remodelling, we identify commonalities and differences, as well as highlighting major knowledge gaps, across arthropod groups. We examine the available evidence supporting current models of how components operate together to prepare for, execute, and recover from ecdysis, comparing reports from Chelicerata, Myriapoda, Crustacea, and Hexapoda. Evidence is generally highly taxonomically imbalanced, with most reports based on insect study systems. Biases are also evident in research on different moulting phases and processes, with the early triggers and late effectors generally being the least well explored. Our synthesis contrasts knowledge based on reported observations with reasonably plausible assumptions given current taxonomic sampling, and exposes weak assumptions or major gaps that need addressing. Encouragingly, advances in genomics are driving a diversification of tractable study systems by facilitating the cataloguing of putative genetic toolkits in previously under-explored taxa. Analysis of genome and transcriptome data supported by experimental investigations have validated the presence of an "ultra-conserved" core of arthropod genes involved in moulting processes. The molecular machinery has likely evolved with elaborations on this conserved pathway backbone, but more taxonomic exploration is needed to characterise lineage-specific changes and novelties. Furthermore, linking these to transformative innovations in moulting processes across Arthropoda remains hampered by knowledge gaps and hypotheses based on untested assumptions. Promisingly however, emerging from the synthesis is a framework that highlights research avenues from the underlying genetics to the dynamic molecular biology through to the complex physiology of moulting.
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Affiliation(s)
- Giulia Campli
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
| | - Olga Volovych
- The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus - Givat Ram, Jerusalem, 9190401, Israel
| | - Kenneth Kim
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
| | - Werner P Veldsman
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
| | - Harriet B Drage
- Institute of Earth Sciences, Quartier UNIL-Mouline, Bâtiment Géopolis, University of Lausanne, Lausanne, 1015, Switzerland
| | - Idan Sheizaf
- The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus - Givat Ram, Jerusalem, 9190401, Israel
| | - Sinéad Lynch
- Institute of Earth Sciences, Quartier UNIL-Mouline, Bâtiment Géopolis, University of Lausanne, Lausanne, 1015, Switzerland
| | - Ariel D Chipman
- The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus - Givat Ram, Jerusalem, 9190401, Israel
| | - Allison C Daley
- Institute of Earth Sciences, Quartier UNIL-Mouline, Bâtiment Géopolis, University of Lausanne, Lausanne, 1015, Switzerland
| | - Marc Robinson-Rechavi
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
| | - Robert M Waterhouse
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
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Anyetei-Anum CS, Leatham-Jensen MP, Fox GC, Smith BR, Krajewski K, Strahl BD, Dowen JM, Matera AG, Duronio RJ, McKay DJ. Dual roles of histone H3 lysine-4 in antagonizing Polycomb group function and promoting target gene expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600669. [PMID: 38979215 PMCID: PMC11230394 DOI: 10.1101/2024.06.25.600669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Tight control over cell identity gene expression is necessary for proper adult form and function. The opposing activities of Polycomb and trithorax complexes determine the ON/OFF state of targets like the Hox genes. Trithorax encodes a methyltransferase specific to histone H3 lysine-4 (H3K4). However, there is no direct evidence that H3K4 regulates Polycomb group target genes in vivo . Here, we demonstrate two key roles for replication-dependent histone H3.2K4 in target control. We find that H3.2K4 antagonizes Polycomb group catalytic activity and that it is required for proper target gene activation. We conclude that H3.2K4 directly regulates expression of Polycomb targets.
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Geens B, Goossens S, Li J, Van de Peer Y, Vanden Broeck J. Untangling the gordian knot: The intertwining interactions between developmental hormone signaling and epigenetic mechanisms in insects. Mol Cell Endocrinol 2024; 585:112178. [PMID: 38342134 DOI: 10.1016/j.mce.2024.112178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/30/2024] [Accepted: 02/04/2024] [Indexed: 02/13/2024]
Abstract
Hormones control developmental and physiological processes, often by regulating the expression of multiple genes simultaneously or sequentially. Crosstalk between hormones and epigenetics is pivotal to dynamically coordinate this process. Hormonal signals can guide the addition and removal of epigenetic marks, steering gene expression. Conversely, DNA methylation, histone modifications and non-coding RNAs can modulate regional chromatin structure and accessibility and regulate the expression of numerous (hormone-related) genes. Here, we provide a review of the interplay between the classical insect hormones, ecdysteroids and juvenile hormones, and epigenetics. We summarize the mode-of-action and roles of these hormones in post-embryonic development, and provide a general overview of epigenetic mechanisms. We then highlight recent advances on the interactions between these hormonal pathways and epigenetics, and their involvement in development. Furthermore, we give an overview of several 'omics techniques employed in the field. Finally, we discuss which questions remain unanswered and possible avenues for future research.
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Affiliation(s)
- Bart Geens
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59 box 2465, B-3000 Leuven, Belgium.
| | - Stijn Goossens
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59 box 2465, B-3000 Leuven, Belgium.
| | - Jia Li
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium; VIB Center for Plant Systems Biology, VIB, Ghent, Belgium.
| | - Yves Van de Peer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium; VIB Center for Plant Systems Biology, VIB, Ghent, Belgium.
| | - Jozef Vanden Broeck
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59 box 2465, B-3000 Leuven, Belgium.
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5
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Ahmed-de-Prado S, Estella C, Baonza A. Temporal dynamics of apoptosis-induced proliferation in pupal wing development: implications for regenerative ability. BMC Biol 2024; 22:98. [PMID: 38679694 PMCID: PMC11057159 DOI: 10.1186/s12915-024-01894-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 04/17/2024] [Indexed: 05/01/2024] Open
Abstract
BACKGROUND The ability of animals to regenerate damaged tissue is a complex process that involves various cellular mechanisms. As animals age, they lose their regenerative abilities, making it essential to understand the underlying mechanisms that limit regenerative ability during aging. Drosophila melanogaster wing imaginal discs are epithelial structures that can regenerate after tissue injury. While significant research has focused on investigating regenerative responses during larval stages our comprehension of the regenerative potential of pupal wings and the underlying mechanisms contributing to the decline of regenerative responses remains limited. RESULTS Here, we explore the temporal dynamics during pupal development of the proliferative response triggered by the induction of cell death, a typical regenerative response. Our results indicate that the apoptosis-induced proliferative response can continue until 34 h after puparium formation (APF), beyond this point cell death alone is not sufficient to induce a regenerative response. Under normal circumstances, cell proliferation ceases around 24 h APF. Interestingly, the failure of reinitiating the cell cycle beyond this time point is not attributed to an incapacity to activate the JNK pathway. Instead, our results suggest that the function of the ecdysone-responsive transcription factor E93 is involved in limiting the apoptosis-induced proliferative response during pupal development. CONCLUSIONS Our study shows that apoptosis can prolong the proliferative period of cells in the wing during pupal development as late as 34 h APF, at least 10 h longer than during normal development. After this time point, the regenerative response is diminished, a process mediated in part by the ecdysone-responsive transcription factor E93.
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Affiliation(s)
| | - Carlos Estella
- Centro de Biología Molecular Severo Ochoa (CSIC/UAM), C/Nicolás Cabrera 1, Madrid, 28049, Spain
| | - Antonio Baonza
- Centro de Biología Molecular Severo Ochoa (CSIC/UAM), C/Nicolás Cabrera 1, Madrid, 28049, Spain.
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6
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Crain AT, Nevil M, Leatham-Jensen MP, Reeves KB, Matera AG, McKay DJ, Duronio RJ. Redesigning the Drosophila histone gene cluster: An improved genetic platform for spatiotemporal manipulation of histone function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.591202. [PMID: 38712307 PMCID: PMC11071459 DOI: 10.1101/2024.04.25.591202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Mutating replication-dependent (RD) histone genes is an important tool for understanding chromatin-based epigenetic regulation. Deploying this tool in metazoan models is particularly challenging because RD histones in these organisms are typically encoded by many genes, often located at multiple loci. Such RD histone gene arrangements make the ability to generate homogenous histone mutant genotypes by site-specific gene editing quite difficult. Drosophila melanogaster provides a solution to this problem because the RD histone genes are organized into a single large tandem array that can be deleted and replaced with transgenes containing mutant histone genes. In the last ∼15 years several different RD histone gene replacement platforms have been developed using this simple strategy. However, each platform contains weaknesses that preclude full use of the powerful developmental genetic capabilities available to Drosophila researchers. Here we describe the development of a newly engineered platform that rectifies many of these weaknesses. We used CRISPR to precisely delete the RD histone gene array ( HisC ), replacing it with a multifunctional cassette that permits site-specific insertion of either one or two synthetic gene arrays using selectable markers. We designed this cassette with the ability to selectively delete each of the integrated gene arrays in specific tissues using site-specific recombinases. We also present a method for rapidly synthesizing histone gene arrays of any genotype using Golden Gate cloning technologies. These improvements facilitate generation of histone mutant cells in various tissues at different stages of Drosophila development and provide an opportunity to apply forward genetic strategies to interrogate chromatin structure and gene regulation.
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Niederhuber MJ, Leatham-Jensen M, McKay DJ. The SWI/SNF nucleosome remodeler constrains enhancer activity during Drosophila wing development. Genetics 2024; 226:iyad196. [PMID: 37949841 PMCID: PMC10847718 DOI: 10.1093/genetics/iyad196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/05/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023] Open
Abstract
Chromatin remodeling is central to the dynamic changes in gene expression that drive cell fate determination. During development, the sets of enhancers that are accessible for use change globally as cells transition between stages. While transcription factors and nucleosome remodelers are known to work together to control enhancer accessibility, it is unclear how the short stretches of DNA that they individually unmask yield the kilobase-sized accessible regions characteristic of active enhancers. Here, we performed a genetic screen to investigate the role of nucleosome remodelers in control of dynamic enhancer activity. We find that the Drosophila Switch/Sucrose Non-Fermenting complex, BAP, is required for repression of a temporally dynamic enhancer, brdisc. Contrary to expectations, we find that the BAP-specific subunit Osa is dispensable for mediating changes in chromatin accessibility between the early and late stages of wing development. Instead, we find that Osa is required to constrain the levels of brdisc activity when the enhancer is normally active. Genome-wide profiling reveals that Osa directly binds brdisc as well as thousands of other developmentally dynamic regulatory sites, including multiple genes encoding components and targets of the Notch signaling pathway. Transgenic reporter analyses demonstrate that Osa is required for activation and for constraint of different sets of target enhancers in the same cells. Moreover, Osa loss results in hyperactivation of the Notch ligand Delta and development of ectopic sensory structures patterned by Notch signaling early in development. Together, these findings indicate that proper constraint of enhancer activity is necessary for regulation of dose-dependent developmental events.
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Affiliation(s)
- Matthew J Niederhuber
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Mary Leatham-Jensen
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Daniel J McKay
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Morrow H, Mirth CK. Timing Drosophila development through steroid hormone action. Curr Opin Genet Dev 2024; 84:102148. [PMID: 38271845 DOI: 10.1016/j.gde.2023.102148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/15/2023] [Accepted: 12/15/2023] [Indexed: 01/27/2024]
Abstract
Specifically timed pulses of the moulting hormone ecdysone are necessary for developmental progression in insects, guiding development through important milestones such as larval moults, pupation and metamorphosis. It also coordinates the acquisition of cell identities, known as cell patterning, and growth in a tissue-specific manner. In the absence of ecdysone, the ecdysone receptor heterodimer Ecdysone Receptor and Ultraspiracle represses expression of target primary response genes, which become de-repressed as the ecdysone titre rises. However, ecdysone signalling elicits both repressive and activating responses in a temporal and tissue-specific manner. To understand how ecdysone achieves such specificity, this review explores the layers of gene regulation involved in stage-appropriate ecdysone responses in Drosophila fruit flies.
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Affiliation(s)
- Hannah Morrow
- School of Biological Sciences, Monash University, Clayton, Victoria 3000, Australia.
| | - Christen K Mirth
- School of Biological Sciences, Monash University, Clayton, Victoria 3000, Australia
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Zhang S, Wu S, Yao R, Wei X, Ohlstein B, Guo Z. Eclosion muscles secrete ecdysteroids to initiate asymmetric intestinal stem cell division in Drosophila. Dev Cell 2024; 59:125-140.e12. [PMID: 38096823 DOI: 10.1016/j.devcel.2023.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 10/05/2023] [Accepted: 11/14/2023] [Indexed: 01/11/2024]
Abstract
During organ development, tissue stem cells first expand via symmetric divisions and then switch to asymmetric divisions to minimize the time to obtain a mature tissue. In the Drosophila midgut, intestinal stem cells switch their divisions from symmetric to asymmetric at midpupal development to produce enteroendocrine cells. However, the signals that initiate this switch are unknown. Here, we identify the signal as ecdysteroids. In the presence of ecdysone, EcR and Usp promote the expression of E93 to suppress Br expression, resulting in asymmetric divisions. Surprisingly, the primary source of pupal ecdysone is not from the prothoracic gland but from dorsal internal oblique muscles (DIOMs), a group of transient skeletal muscles that are required for eclosion. Genetic analysis shows that DIOMs secrete ecdysteroids during mTOR-mediated muscle remodeling. Our findings identify sequential endocrine and mechanical roles for skeletal muscle, which ensure the timely asymmetric divisions of intestinal stem cells.
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Affiliation(s)
- Song Zhang
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Song Wu
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Ruining Yao
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Xueying Wei
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Benjamin Ohlstein
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Zheng Guo
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.
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10
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Pelayo MA, Yamaguchi N. Old school, new rules: floral meristem development revealed by 3D gene expression atlases and high-resolution transcription factor-chromatin dynamics. FRONTIERS IN PLANT SCIENCE 2023; 14:1323507. [PMID: 38155851 PMCID: PMC10753784 DOI: 10.3389/fpls.2023.1323507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 11/23/2023] [Indexed: 12/30/2023]
Abstract
The intricate morphology of the flower is primarily established within floral meristems in which floral organs will be defined and from where the developing flower will emerge. Floral meristem development involves multiscale-level regulation, including lineage and positional mechanisms for establishing cell-type identity, and transcriptional regulation mediated by changes in the chromatin environment. However, many key aspects of floral meristem development remain to be determined, such as: 1) the exact role of cellular location in connecting transcriptional inputs to morphological outcomes, and 2) the precise interactions between transcription factors and chromatin regulators underlying the transcriptional networks that regulate the transition from cell proliferation to differentiation during floral meristem development. Here, we highlight recent studies addressing these points through newly developed spatial reconstruction techniques and high-resolution transcription factor-chromatin environment interactions in the model plant Arabidopsis thaliana. Specifically, we feature studies that reconstructed 3D gene expression atlases of the floral meristem. We also discuss how the precise timing of floral meristem specification, floral organ patterning, and floral meristem termination is determined through temporally defined epigenetic dynamics for fine-tuning of gene expression. These studies offer fresh insights into the well-established principles of floral meristem development and outline the potential for further advances in this field in an age of integrated, powerful, multiscale resolution approaches.
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Affiliation(s)
| | - Nobutoshi Yamaguchi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
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11
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Komatsu V, Cooper B, Yim P, Chan K, Gong W, Wheatley L, Rohs R, Fraser SE, Trinh LA. Hand2 represses non-cardiac cell fates through chromatin remodeling at cis- regulatory elements. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.23.559156. [PMID: 37790542 PMCID: PMC10542161 DOI: 10.1101/2023.09.23.559156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Developmental studies have revealed the importance of the transcription factor Hand2 in cardiac development. Hand2 promotes cardiac progenitor differentiation and epithelial maturation, while repressing other tissue types. The mechanisms underlying the promotion of cardiac fates are far better understood than those underlying the repression of alternative fates. Here, we assess Hand2-dependent changes in gene expression and chromatin remodeling in cardiac progenitors of zebrafish embryos. Cell-type specific transcriptome analysis shows a dual function for Hand2 in activation of cardiac differentiation genes and repression of pronephric pathways. We identify functional cis- regulatory elements whose chromatin accessibility are increased in hand2 mutant cells. These regulatory elements associate with non-cardiac gene expression, and drive reporter gene expression in tissues associated with Hand2-repressed genes. We find that functional Hand2 is sufficient to reduce non-cardiac reporter expression in cardiac lineages. Taken together, our data support a model of Hand2-dependent coordination of transcriptional programs, not only through transcriptional activation of cardiac and epithelial maturation genes, but also through repressive chromatin remodeling at the DNA regulatory elements of non-cardiac genes.
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12
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Zhang J, Zhang W, Wei L, Zhang L, Liu J, Huang S, Li S, Yang W, Li K. E93 promotes transcription of RHG genes to initiate apoptosis during Drosophila salivary gland metamorphosis. INSECT SCIENCE 2023; 30:588-598. [PMID: 36281570 DOI: 10.1111/1744-7917.13135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/03/2022] [Accepted: 10/14/2022] [Indexed: 06/15/2023]
Abstract
20-hydroxyecdysone (20E) induced transcription factor E93 is important for larval-adult transition, which functions in programmed cell death of larval obsolete tissues, and the formation of adult new tissues. However, the apoptosis-related genes directly regulated by E93 are still ambiguous. In this study, an E93 mutation fly strain was obtained by clustered regularly interspaced palindromic repeats (CRISPR) / CRISPR-associated protein 9-mediated long exon deletion to investigate whether and how E93 induces apoptosis during larval tissues metamorphosis. The transcriptional profile of E93 was consistent with 3 RHG (rpr, hid, and grim) genes and the effector caspase gene drice, and all their expressions peaked at the initiation of apoptosis during the degradation of salivary glands. The transcription expression of 3 RHG genes decreased and apoptosis was blocked in E93 mutation salivary gland during metamorphosis. In contrast, E93 overexpression promoted the transcription of 3 RHG genes, and induced advanced apoptosis in the salivary gland. Moreover, E93 not only enhance the promoter activities of the 3 RHG genes in Drosophila Kc cells in vitro, but also in the salivary gland in vivo. Our results demonstrated that 20E induced E93 promotes the transcription of RHG genes to trigger apoptosis during obsolete tissues degradation at metamorphosis in Drosophila.
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Affiliation(s)
- Jiahui Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, 510642, China
| | - Wenhao Zhang
- College of Biological and Food Engineering, Huaihua University, Huaihua, 418000, China
| | - Lin Wei
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Lidan Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Jiali Liu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Shumin Huang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Sheng Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, 510642, China
- Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou, 514779, China
| | - Weike Yang
- The Sericultural and Apicultural Research Institute, Yunnan Academy of Agricultural Sciences, Mengzi, Yunnan, 661100, China
| | - Kang Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, 510642, China
- Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou, 514779, China
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13
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Li K, Liu K, Wang X, Ma M, Luo X, Chen W, Chen A, Peng Z, Zhang D. Role of nuclear receptors NlHR3 and NlFTZ-F1 in regulating molting and reproduction in Nilaparvata lugens (stål). Front Physiol 2023; 14:1123583. [PMID: 37008006 PMCID: PMC10050704 DOI: 10.3389/fphys.2023.1123583] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/23/2023] [Indexed: 03/17/2023] Open
Abstract
The nuclear receptors HR3 and FTZ-F1 are highly conserved and function to regulate molting and reproduction in both hemimetabolous and holometabolous insects. However, their roles in Nilaparvata lugens are largely unknown. In the present study, we discover that NlHR3 and NlFTZ-F1 are activated in the nymph stages by ecdysone signaling. Transcription disruption of NlHR3 and NlFTZ-F1 expression prevents nymph ecdysis and metamorphosis, which leads to abnormal appearance, malformed ovaries, and lethal phenotypes. In addition, we demonstrate that NlHR3 and NlFTZ-F1 regulate molting and reproduction by interacting with the intrinsic 20E and JH signaling pathways. Our work offers a deep insight into the action mechanisms of HR3 and FTZ-F1 in insects. Moreover, NlHR3 and NlFTZ-F1 could properly be exploited as potential target genes for developing RNAi-based pesticides to control N. lugens.
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Affiliation(s)
- Kailong Li
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, China
| | - Kanghong Liu
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, China
| | - Xing Wang
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, China
| | - Mingyong Ma
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, China
| | - Xiangwen Luo
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, China
| | - Wuying Chen
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, China
| | - Ang Chen
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, China
| | - Zhaopu Peng
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, China
| | - Deyong Zhang
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, China
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14
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Ling L, Mühling B, Jaenichen R, Gompel N. Increased chromatin accessibility promotes the evolution of a transcriptional silencer in Drosophila. SCIENCE ADVANCES 2023; 9:eade6529. [PMID: 36800429 PMCID: PMC9937571 DOI: 10.1126/sciadv.ade6529] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
The loss of discrete morphological traits, the most common evolutionary transition, is typically driven by changes in developmental gene expression. Mutations accumulating in regulatory elements of these genes can disrupt DNA binding sites for transcription factors patterning their spatial expression, or delete entire enhancers. Regulatory elements, however, may be silenced through changes in chromatin accessibility or the emergence of repressive elements. Here, we show that increased chromatin accessibility at the gene yellow, combined with the gain of a repressor site, underlies the loss of a wing spot pigmentation pattern in a Drosophila species. The gain of accessibility of this repressive element is regulated by E93, a transcription factor governing the progress of metamorphosis. This convoluted evolutionary scenario contrasts with the parsimonious mutational paths generally envisioned and often documented for morphological losses. It illustrates how evolutionary changes in chromatin accessibility may directly contribute to morphological diversification.
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15
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Reduction of embryonic E93 expression as a hypothetical driver of the evolution of insect metamorphosis. Proc Natl Acad Sci U S A 2023; 120:e2216640120. [PMID: 36745781 PMCID: PMC9963766 DOI: 10.1073/pnas.2216640120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The early embryo of the cockroach Blattella germanica exhibits high E93 expression. In general, E93 triggers adult morphogenesis during postembryonic development. Here we show that E93 is also crucial in early embryogenesis in the cockroach, as a significant number of E93-depleted embryos are unable to develop the germ band under maternal RNAi treatment targeting E93. Moreover, transcriptomic analysis indicates that E93 depletion results in important gene expression changes in the early embryo, and many of the differentially expressed genes are involved in development. Then, using public databases, we gathered E93 expression data in embryo and preadult stages, finding that embryonic expression of E93 is high in hemimetabolan species (whose juveniles, or nymphs, are similar to the adult) and low in holometabolans (whose juveniles, or larvae, are different from the adult). E93 expression is also low in Thysanoptera and in Hemiptera Sternorrhyncha, hemimetabolans with postembryonic quiescent stages, as well as in Odonata, the nymph of which is very different from the adult. In ametabolans, such as the Zygentoma Thermobia domestica, E93 transcript levels are very high in the early embryo, whereas during postembryonic development they are medium and relatively constant. We propose the hypothesis that during evolution, a reduction of E93 expression in the embryo of hemimetabolans facilitated the larval development and the emergence of holometaboly. Independent decreases of E93 transcripts in the embryo of Odonata, Thysanoptera, and different groups of Hemiptera Sternorrhyncha would have allowed the development of modified juvenile stages adapted to specific ecophysiological conditions.
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16
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Okamoto N, Fujinaga D, Yamanaka N. Steroid hormone signaling: What we can learn from insect models. VITAMINS AND HORMONES 2023; 123:525-554. [PMID: 37717997 DOI: 10.1016/bs.vh.2022.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Ecdysteroids are a group of steroid hormones in arthropods with pleiotropic functions throughout their life history. Ecdysteroid research in insects has made a significant contribution to our current understanding of steroid hormone signaling in metazoans, but how far can we extrapolate our findings in insects to other systems, such as mammals? In this chapter, we compare steroid hormone signaling in insects and mammals from multiple perspectives and discuss similarities and differences between the two lineages. We also highlight a few understudied areas and remaining questions of steroid hormone biology in metazoans and propose potential future research directions.
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Affiliation(s)
- Naoki Okamoto
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Daiki Fujinaga
- Department of Entomology, University of California, Riverside, CA, United States
| | - Naoki Yamanaka
- Department of Entomology, University of California, Riverside, CA, United States.
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17
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Matsumura Y, To TK, Kunieda T, Kohno H, Kakutani T, Kubo T. Mblk-1/E93, an ecdysone related-transcription factor, targets synaptic plasticity-related genes in the honey bee mushroom bodies. Sci Rep 2022; 12:21367. [PMID: 36494426 PMCID: PMC9734179 DOI: 10.1038/s41598-022-23329-z] [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: 04/30/2022] [Accepted: 10/29/2022] [Indexed: 12/13/2022] Open
Abstract
Among hymenopteran insects, aculeate species such as bees, ants, and wasps have enlarged and morphologically elaborate mushroom bodies (MBs), a higher-order brain center in the insect, implying their relationship with the advanced behavioral traits of aculeate species. The molecular bases leading to the acquisition of complicated MB functions, however, remains unclear. We previously reported the constitutive and MB-preferential expression of an ecdysone-signaling related transcription factor, Mblk-1/E93, in the honey bee brain. Here, we searched for target genes of Mblk-1 in the worker honey bee MBs using chromatin immunoprecipitation sequence analyses and found that Mblk-1 targets several genes involved in synaptic plasticity, learning, and memory abilities. We also demonstrated that Mblk-1 expression is self-regulated via Mblk-1-binding sites, which are located upstream of Mblk-1. Furthermore, we showed that the number of the Mblk-1-binding motif located upstream of Mblk-1 homologs increased associated with evolution of hymenopteran insects. Our findings suggest that Mblk-1, which has been focused on as a developmental gene transiently induced by ecdysone, has acquired a novel expression pattern to play a role in synaptic plasticity in honey bee MBs, raising a possibility that molecular evolution of Mblk-1 may have partly contributed to the elaboration of MB function in insects.
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Affiliation(s)
- Yasuhiro Matsumura
- grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Taiko Kim To
- grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takekazu Kunieda
- grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hiroki Kohno
- grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tetsuji Kakutani
- grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takeo Kubo
- grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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18
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Zhu GH, Gaddelapati SC, Jiao Y, Koo J, Palli SR. CRISPR-Cas9 Genome Editing Uncovers the Mode of Action of Methoprene in the Yellow Fever Mosquito, Aedes aegypti. CRISPR J 2022; 5:813-824. [PMID: 36374965 PMCID: PMC9805843 DOI: 10.1089/crispr.2022.0066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Methoprene, a juvenile hormone (JH) analog, is widely used for insect control, but its mode of action is not known. To study methoprene action in the yellow fever mosquito, Aedes aegypti, the E93 (ecdysone-induced transcription factor) was knocked out using the CRISPR-Cas9 system. The E93 mutant pupae retained larval tissues similar to methoprene-treated insects. These insects completed pupal ecdysis and died as pupa. In addition, the expression of transcription factors, broad complex and Krüppel homolog 1 (Kr-h1), increased and that of programmed cell death (PCD) and autophagy genes decreased in E93 mutants. These data suggest that methoprene functions through JH receptor, methoprene-tolerant, and induces the expression of Kr-h1, which suppresses the expression of E93, resulting in a block in PCD and autophagy of larval tissues. Failure in the elimination of larval tissues and the formation of adult structures results in their death. These results answered long-standing questions on the mode of action of methoprene.
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Affiliation(s)
- Guan-Heng Zhu
- Department of Entomology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA
| | - Sharath Chandra Gaddelapati
- Department of Entomology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA
| | - Yaoyu Jiao
- Department of Entomology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA
| | - Jinmo Koo
- Department of Entomology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA
| | - Subba Reddy Palli
- Department of Entomology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.,Address correspondence to: Subba Reddy Palli, Department of Entomology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY 40546, USA.
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19
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Knockdown of Ecdysone-Induced Protein 93F Causes Abnormal Pupae and Adults in the Eggplant Lady Beetle. BIOLOGY 2022; 11:biology11111640. [DOI: 10.3390/biology11111640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/02/2022] [Accepted: 11/02/2022] [Indexed: 11/12/2022]
Abstract
Ecdysone-induced protein 93F (E93) plays triple roles during post-embryonic development in insects whose juvenile instars are more than four. However, it only acts as a specifier of adult structures in Drosophila flies whose larval instars are fixed at three. In this study, we determined the functions of E93 in the eggplant lady beetle (Henosepilachna vigintioctopunctata), which has four larval instars. We uncovered that E93 was abundantly expressed at the prepupal and pupal stages. A precocious inhibition of the juvenile hormone signal by RNA interference (RNAi) of HvKr-h1 or HvHairy, two vital downstream developmental effectors, at the penultimate instar larval stage increased the expression of E93, Conversely, ingestion of JH by the third-instar larvae stimulated the expression of HvKr-h1 but repressed the transcription of either HvE93X1 or HvE93X2. However, disturbance of the JH signal neither drove premature metamorphosis nor caused supernumerary instars. In contrast, depletion of E93 at the third- and fourth-instar larval and prepupal stages severely impaired pupation and caused a larval-pupal mixed phenotype: pupal spines and larval scoli were simultaneously presented on the cuticle. RNAi of E93 at the pupal stage affected adult eclosion. When the beetles had suffered from a dsE93 injection at the fourth-instar larval and pupal stages, a few resultant adults emerged, with separated elytra, abnormally folded hindwings, a small body size and short appendages. Taken together, our results suggest the larval instars are fixed in H. vigintioctopunctata; E93 serves as a repressor of larval characters and a specifier of adult structures during the larval–pupal–adult transition.
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20
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Opportunistic binding of EcR to open chromatin drives tissue-specific developmental responses. Proc Natl Acad Sci U S A 2022; 119:e2208935119. [PMID: 36161884 DOI: 10.1073/pnas.2208935119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Steroid hormones perform diverse biological functions in developing and adult animals. However, the mechanistic basis for their tissue specificity remains unclear. In Drosophila, the ecdysone steroid hormone is essential for coordinating developmental timing across physically separated tissues. Ecdysone directly impacts genome function through its nuclear receptor, a heterodimer of the EcR and ultraspiracle proteins. Ligand binding to EcR triggers a transcriptional cascade, including activation of a set of primary response transcription factors. The hierarchical organization of this pathway has left the direct role of EcR in mediating ecdysone responses obscured. Here, we investigate the role of EcR in controlling tissue-specific ecdysone responses, focusing on two tissues that diverge in their response to rising ecdysone titers: the larval salivary gland, which undergoes programmed destruction, and the wing imaginal disc, which initiates morphogenesis. We find that EcR functions bimodally, with both gene repressive and activating functions, even at the same developmental stage. EcR DNA binding profiles are highly tissue-specific, and transgenic reporter analyses demonstrate that EcR plays a direct role in controlling enhancer activity. Finally, despite a strong correlation between tissue-specific EcR binding and tissue-specific open chromatin, we find that EcR does not control chromatin accessibility at genomic targets. We conclude that EcR contributes extensively to tissue-specific ecdysone responses. However, control over access to its binding sites is subordinated to other transcription factors.
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21
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Essential functions of mosquito ecdysone importers in development and reproduction. Proc Natl Acad Sci U S A 2022; 119:e2202932119. [PMID: 35696563 PMCID: PMC9231622 DOI: 10.1073/pnas.2202932119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Steroid hormones control sexual maturation and reproduction in insects and humans alike. The insect steroid hormone ecdysone uses a membrane transporter named Ecdysone Importer (EcI) to enter cells and promote these physiological processes, but EcI is unexpectedly missing in mosquito genomes. Using the yellow fever mosquito Aedes aegypti, here we show that mosquitoes use alternative ecdysone importers to facilitate ecdysone-dependent development and reproduction. These transporters are also present in other insects, including fruit flies, but they are dispensable for fly development and reproduction likely due to their limited expression patterns. Our results thus indicate that differential expression of steroid hormone importers enables tissue- and stage-specific hormone responses, and some importers can obtain critical physiological functions only in certain species. The primary insect steroid hormone ecdysone requires a membrane transporter to enter its target cells. Although an organic anion-transporting polypeptide (OATP) named Ecdysone Importer (EcI) serves this role in the fruit fly Drosophila melanogaster and most likely in other arthropod species, this highly conserved transporter is apparently missing in mosquitoes. Here we report three additional OATPs that facilitate cellular incorporation of ecdysone in Drosophila and the yellow fever mosquito Aedes aegypti. These additional ecdysone importers (EcI-2, -3, and -4) are dispensable for development and reproduction in Drosophila, consistent with the predominant role of EcI. In contrast, in Aedes, EcI-2 is indispensable for ecdysone-mediated development, whereas EcI-4 is critical for vitellogenesis induced by ecdysone in adult females. Altogether, our results indicate unique and essential functions of these additional ecdysone importers in mosquito development and reproduction, making them attractive molecular targets for species- and stage-specific control of ecdysone signaling in mosquitoes.
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22
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Chinmo is the larval member of the molecular trinity that directs Drosophila metamorphosis. Proc Natl Acad Sci U S A 2022; 119:e2201071119. [PMID: 35377802 PMCID: PMC9169713 DOI: 10.1073/pnas.2201071119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The genome of insects with complete metamorphosis contains the instructions for making three distinct body forms, that of the larva, of the pupa, and of the adult. However, the molecular mechanisms by which each gene set is called forth and stably expressed are poorly understood. A half century ago, it was proposed that there was a set of three master genes that inhibited each other’s expression and enabled the expression of genes for each respective stage. We show that the transcription factor chinmo is essential for maintaining the larval stage in Drosophila, and with two other regulatory genes, broad and E93, makes up the trinity of mutually repressive master genes that underlie insect metamorphosis. The molecular control of insect metamorphosis from larva to pupa to adult has long been a mystery. The Broad and E93 transcription factors, which can modify chromatin domains, are known to direct the production of the pupa and the adult, respectively. We now show that chinmo, a gene related to broad, is essential for the repression of these metamorphic genes. Chinmo is strongly expressed during the formation and growth of the larva and its removal results in the precocious expression of broad and E93 in the first stage larva, causing a shift from larval to premetamorphic functions. This trinity of Chinmo, Broad, and E93 regulatory factors is mutually inhibitory. The interaction of this network with regulatory hormones likely ensures the orderly progression through insect metamorphosis.
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23
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Jaszczak JS, DeVault L, Jan LY, Jan YN. Steroid hormone signaling activates thermal nociception during Drosophila peripheral nervous system development. eLife 2022; 11:e76464. [PMID: 35353036 PMCID: PMC8967384 DOI: 10.7554/elife.76464] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/07/2022] [Indexed: 12/27/2022] Open
Abstract
Sensory neurons enable animals to detect environmental changes and avoid harm. An intriguing open question concerns how the various attributes of sensory neurons arise in development. Drosophila melanogaster larvae undergo a behavioral transition by robustly activating a thermal nociceptive escape behavior during the second half of larval development (third instar). The Class IV dendritic arborization (C4da) neurons are multimodal sensors which tile the body wall of Drosophila larvae and detect nociceptive temperature, light, and mechanical force. In contrast to the increase in nociceptive behavior in the third instar, we find that ultraviolet light-induced Ca2+ activity in C4da neurons decreases during the same period of larval development. Loss of ecdysone receptor has previously been shown to reduce nociception in third instar larvae. We find that ligand-dependent activation of ecdysone signaling is sufficient to promote nociceptive responses in second instar larvae and suppress expression of subdued (encoding a TMEM16 channel). Reduction of subdued expression in second instar C4da neurons not only increases thermal nociception but also decreases the response to ultraviolet light. Thus, steroid hormone signaling suppresses subdued expression to facilitate the sensory switch of C4da neurons. This regulation of a developmental sensory switch through steroid hormone regulation of channel expression raises the possibility that ion channel homeostasis is a key target for tuning the development of sensory modalities.
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Affiliation(s)
- Jacob S Jaszczak
- Department of Physiology, Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Laura DeVault
- Department of Physiology, Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Department of Developmental Biology, Washington University Medical SchoolSaint LouisUnited States
| | - Lily Yeh Jan
- Department of Physiology, Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Yuh Nung Jan
- Department of Physiology, Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
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24
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Lam G, Nam HJ, Velentzas PD, Baehrecke EH, Thummel CS. Drosophila E93 promotes adult development and suppresses larval responses to ecdysone during metamorphosis. Dev Biol 2022; 481:104-115. [PMID: 34648816 PMCID: PMC8665130 DOI: 10.1016/j.ydbio.2021.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 01/03/2023]
Abstract
Pulses of the steroid hormone ecdysone act through transcriptional cascades to direct the major developmental transitions during the Drosophila life cycle. These include the prepupal ecdysone pulse, which occurs 10 hours after pupariation and triggers the onset of adult morphogenesis and larval tissue destruction. E93 encodes a transcription factor that is specifically induced by the prepupal pulse of ecdysone, supporting a model proposed by earlier work that it specifies the onset of adult development. Although a number of studies have addressed these functions for E93, little is known about its roles in the salivary gland where the E93 locus was originally identified. Here we show that E93 is required for development through late pupal stages, with mutants displaying defects in adult differentiation and no detectable effect on the destruction of larval salivary glands. RNA-seq analysis demonstrates that E93 regulates genes involved in development and morphogenesis in the salivary glands, but has little effect on cell death gene expression. We also show that E93 is required to direct the proper timing of ecdysone-regulated gene expression in salivary glands, and that it suppresses earlier transcriptional programs that occur during larval and prepupal stages. These studies support the model that the stage-specific induction of E93 in late prepupae provides a critical signal that defines the end of larval development and the onset of adult differentiation.
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Affiliation(s)
- Geanette Lam
- Department of Human Genetics, University of Utah School of Medicine, 15 N 2030 E Rm 5100, Salt Lake City, UT 84112 USA
| | - Hyuck-Jin Nam
- Department of Human Genetics, University of Utah School of Medicine, 15 N 2030 E Rm 5100, Salt Lake City, UT 84112 USA
| | - Panagiotis D. Velentzas
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Eric H. Baehrecke
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Carl S. Thummel
- Department of Human Genetics, University of Utah School of Medicine, 15 N 2030 E Rm 5100, Salt Lake City, UT 84112 USA,Corresponding author. (C.S. Thummel)
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25
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Glastad KM, Ju L, Berger SL. Tramtrack acts during late pupal development to direct ant caste identity. PLoS Genet 2021; 17:e1009801. [PMID: 34550980 PMCID: PMC8489709 DOI: 10.1371/journal.pgen.1009801] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/04/2021] [Accepted: 09/01/2021] [Indexed: 11/17/2022] Open
Abstract
A key question in the rising field of neuroepigenetics is how behavioral plasticity is established and maintained in the developing CNS of multicellular organisms. Behavior is controlled through systemic changes in hormonal signaling, cell-specific regulation of gene expression, and changes in neuronal connections in the nervous system, however the link between these pathways is unclear. In the ant Camponotus floridanus, the epigenetic corepressor CoREST is a central player in experimentally-induced reprogramming of caste-specific behavior, from soldier (Major worker) to forager (Minor worker). Here, we show this pathway is engaged naturally on a large genomic scale during late pupal development targeting multiple genes differentially expressed between castes, and central to this mechanism is the protein tramtrack (ttk), a DNA binding partner of CoREST. Caste-specific differences in DNA binding of ttk co-binding with CoREST correlate with caste-biased gene expression both in the late pupal stage and immediately after eclosion. However, we find a unique set of exclusive Minor-bound genes that show ttk pre-binding in the late pupal stage preceding CoREST binding, followed by caste-specific gene repression on the first day of eclosion. In addition, we show that ttk binding correlates with neurogenic Notch signaling, and that specific ttk binding between castes is enriched for regulatory sites associated with hormonal function. Overall our findings elucidate a pathway of transcription factor binding leading to a repressive epigenetic axis that lies at the crux of development and hormonal signaling to define worker caste identity in C. floridanus.
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Affiliation(s)
- Karl M Glastad
- Department of Cell and Developmental Biology, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania United States of America.,Epigenetics Institute; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania United States of America
| | - Linyang Ju
- Epigenetics Institute; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania United States of America.,Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania United States of America
| | - Shelley L Berger
- Department of Cell and Developmental Biology, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania United States of America.,Epigenetics Institute; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania United States of America.,Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania United States of America
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Mika K, Cruchet S, Chai PC, Prieto-Godino LL, Auer TO, Pradervand S, Benton R. Olfactory receptor-dependent receptor repression in Drosophila. SCIENCE ADVANCES 2021; 7:eabe3745. [PMID: 34362730 PMCID: PMC8346220 DOI: 10.1126/sciadv.abe3745] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 06/17/2021] [Indexed: 06/01/2023]
Abstract
In olfactory systems across phyla, most sensory neurons express a single olfactory receptor gene selected from a large genomic repertoire. We describe previously unknown receptor gene-dependent mechanisms that ensure singular expression of receptors encoded by a tandem gene array [Ionotropic receptor 75c (Ir75c), Ir75b, and Ir75a, organized 5' to 3'] in Drosophila melanogaster Transcription from upstream genes in the cluster runs through the coding region of downstream loci and inhibits their expression in cis, most likely via transcriptional interference. Moreover, Ir75c blocks accumulation of other receptor proteins in trans through a protein-dependent, posttranscriptional mechanism. These repression mechanisms operate in endogenous neurons, in conjunction with cell type-specific gene regulatory networks, to ensure unique receptor expression. Our data provide evidence for inter-olfactory receptor regulation in invertebrates and highlight unprecedented, but potentially widespread, mechanisms for ensuring exclusive expression of chemosensory receptors, and other protein families, encoded by tandemly arranged genes.
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Affiliation(s)
- Kaan Mika
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Steeve Cruchet
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Phing Chian Chai
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Lucia L Prieto-Godino
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Thomas O Auer
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Sylvain Pradervand
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
- Lausanne Genomic Technologies Facility, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
- Vital-IT Group, Swiss Institute of Bioinformatics, CH-1015 Lausanne, Switzerland
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland.
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Cohen E, Peterson NG, Sawyer JK, Fox DT. Accelerated cell cycles enable organ regeneration under developmental time constraints in the Drosophila hindgut. Dev Cell 2021; 56:2059-2072.e3. [PMID: 34019841 PMCID: PMC8319103 DOI: 10.1016/j.devcel.2021.04.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/10/2021] [Accepted: 04/28/2021] [Indexed: 12/22/2022]
Abstract
Individual organ development must be temporally coordinated with development of the rest of the organism. As a result, cell division cycles in a developing organ occur on a relatively fixed timescale. Despite this, many developing organs can regenerate cells lost to injury. How organs regenerate within the time constraints of organism development remains unclear. Here, we show that the developing Drosophila hindgut regenerates by accelerating the mitotic cell cycle. This process is achieved by decreasing G1 length and requires the JAK/STAT ligand unpaired-3. Mitotic capacity is then terminated by the steroid hormone ecdysone receptor and the Sox transcription factor Dichaete. These two factors converge on regulation of a hindgut-specific enhancer of fizzy-related, a negative regulator of mitotic cyclins. Our findings reveal how the cell-cycle machinery and cytokine signaling can be adapted to accomplish developmental organ regeneration.
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Affiliation(s)
- Erez Cohen
- Department of Cell Biology, Duke University School of Medicine, Durham, USA
| | - Nora G Peterson
- Department of Cell Biology, Duke University School of Medicine, Durham, USA
| | - Jessica K Sawyer
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, USA
| | - Donald T Fox
- Department of Cell Biology, Duke University School of Medicine, Durham, USA; Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, USA; Regeneration Next Initiative, Duke University School of Medicine, Durham, USA.
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28
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He YZ, Ding Y, Wang X, Zou Z, Raikhel AS. E93 confers steroid hormone responsiveness of digestive enzymes to promote blood meal digestion in the midgut of the mosquito Aedes aegypti. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 134:103580. [PMID: 33901693 PMCID: PMC8947147 DOI: 10.1016/j.ibmb.2021.103580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/19/2021] [Accepted: 04/19/2021] [Indexed: 06/12/2023]
Abstract
Anautogenous female mosquitoes obtain the nutrients needed for egg development from vertebrate blood, and consequently they transmit numerous pathogens of devastating human diseases. Digestion of blood proteins into amino acids that are used for energy production, egg maturation and replenishment of maternal reserves is an essential part of the female mosquito reproductive cycle. However, the regulatory mechanisms underlying this process remain largely unknown. Here, we report that the transcription factor E93 is a critical factor promoting blood meal digestion in adult females of the major arboviral vector Aedes aegypti in response to the steroid hormone 20-hydroxyecdysone (20E). E93 was upregulated in the female mosquito midgut after a blood meal, and RNA interference (RNAi)-mediated knockdown of E93 inhibited midgut blood digestion. E93 RNAi depletion repressed late trypsin (LT), serine protease I (SPI), SPVI and SPVII, and activated early trypsin (ET) expression in the female mosquito midgut after a blood meal. Injection of 20E activated E93, LT, SPI, SPVI and SPVII, and repressed ET expression, whereas RNAi knockdown of the ecdysone receptor (EcR) repressed E93, LT, SPI, SPVI and SPVII, and activated ET expression in the midgut. Furthermore, E93 depletion resulted in a complete loss of 20E responsiveness of LT, SPVI and SPVII. Our findings reveal important mechanisms regulating blood meal digestion in disease-transmitting mosquitoes.
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Affiliation(s)
- Ya-Zhou He
- Department of Entomology, University of California, Riverside, CA, 92521, USA; Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Yike Ding
- Department of Entomology, University of California, Riverside, CA, 92521, USA; Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Xueli Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Alexander S Raikhel
- Department of Entomology, University of California, Riverside, CA, 92521, USA; Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.
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29
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Adult specifier E93 takes control of reproductive cyclicity in mosquitoes. Proc Natl Acad Sci U S A 2021; 118:2102059118. [PMID: 33674423 DOI: 10.1073/pnas.2102059118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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30
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van der Burg KR, Reed RD. Seasonal plasticity: how do butterfly wing pattern traits evolve environmental responsiveness? Curr Opin Genet Dev 2021; 69:82-87. [PMID: 33740694 DOI: 10.1016/j.gde.2021.02.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/03/2021] [Accepted: 02/09/2021] [Indexed: 01/28/2023]
Abstract
Phenotypic plasticity in response to environmental cues is common in butterflies, and is a major driver of butterfly wing pattern diversity. The endocrine signal ecdysone has been revealed as a major modulator of plasticity in butterflies. External cues such as day length or temperature are translated internally into variation in ecdysone titers, which in turn lead to alternate phenotypes such as seasonal wing patterns. Here we review the evidence showing that ecdysone-mediated plasticity of different wing pattern features such as wing color and eyespot size can evolve independently. Recent studies show that ecdysone regulates gene expression in Drosophila melanogaster via a chromatin remodeling mechanism. We thus propose that environmentally responsive ecdysone titers in butterflies may also function via chromatin regulation to promote different seasonal phenotypes. We present a model of ecdysone response evolution that integrates both gene regulatory architecture and organismal development, and propose a set of testable mechanistic hypotheses for how plastic response profiles of specific genes can evolve.
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Affiliation(s)
- Karin Rl van der Burg
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, United States.
| | - Robert D Reed
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, United States.
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31
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Wang X, Ding Y, Lu X, Geng D, Li S, Raikhel AS, Zou Z. The ecdysone-induced protein 93 is a key factor regulating gonadotrophic cycles in the adult female mosquito Aedes aegypti. Proc Natl Acad Sci U S A 2021; 118:e2021910118. [PMID: 33593917 PMCID: PMC7923369 DOI: 10.1073/pnas.2021910118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Repeated blood feedings are required for adult female mosquitoes to maintain their gonadotrophic cycles, enabling them to be important pathogen carriers of human diseases. Elucidating the molecular mechanism underlying developmental switches between these mosquito gonadotrophic cycles will provide valuable insight into mosquito reproduction and could aid in the identification of targets to disrupt these cycles, thereby reducing disease transmission. We report here that the transcription factor ecdysone-induced protein 93 (E93), previously implicated in insect metamorphic transitions, plays a key role in determining the gonadotrophic cyclicity in adult females of the major arboviral vector Aedes aegypti Expression of the E93 gene in mosquitoes is down-regulated by juvenile hormone (JH) and up-regulated by 20-hydroxyecdysone (20E). We find that E93 controls Hormone Receptor 3 (HR3), the transcription factor linked to the termination of reproductive cycles. Moreover, knockdown of E93 expression via RNAi impaired fat body autophagy, suggesting that E93 governs autophagy-induced termination of vitellogenesis. E93 RNAi silencing prior to the first gonadotrophic cycle affected normal progression of the second cycle. Finally, transcriptomic analysis showed a considerable E93-dependent decline in the expression of genes involved in translation and metabolism at the end of a reproductive cycle. In conclusion, our data demonstrate that E93 acts as a crucial factor in regulating reproductive cycle switches in adult female mosquitoes.
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Affiliation(s)
- Xueli Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Yike Ding
- Department of Entomology, University of California, Riverside, CA 92521
- Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Xiangyang Lu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Danqian Geng
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Shan Li
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Alexander S Raikhel
- Department of Entomology, University of California, Riverside, CA 92521;
- Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China;
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
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32
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Martín D, Chafino S, Franch-Marro X. How stage identity is established in insects: the role of the Metamorphic Gene Network. CURRENT OPINION IN INSECT SCIENCE 2021; 43:29-38. [PMID: 33075581 DOI: 10.1016/j.cois.2020.10.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/07/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
Proper formation of adult insects requires the integration of spatial and temporal regulatory axes. Whereas spatial information confers identity to each tissue, organ and appendage, temporal information specifies at which stage of development the animal is. Regardless of the type of post-embryonic development, either hemimetabolous or holometabolous, temporal specificity is achieved through interactions between the temporal identity genes Kr-h1, E93 and Br-C, whose sequential expression is controlled by the two major developmental hormones, 20-hydroxyecdysone and Juvenile hormone. Given the intimate regulatory connection between these three factors to specify life stage identity, we dubbed the regulatory axis that comprises these genes as the Metamorphic Gene Network (MGN). In this review, we survey the molecular mechanisms underlying the control by the MGN of stage identity and progression in hemimetabolous and holometabolous insects.
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Affiliation(s)
- David Martín
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
| | - Silvia Chafino
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Xavier Franch-Marro
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
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33
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Niederhuber MJ, McKay DJ. Mechanisms underlying the control of dynamic regulatory element activity and chromatin accessibility during metamorphosis. CURRENT OPINION IN INSECT SCIENCE 2021; 43:21-28. [PMID: 32979530 PMCID: PMC7985040 DOI: 10.1016/j.cois.2020.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 08/25/2020] [Indexed: 05/10/2023]
Abstract
Cis-regulatory modules of metazoan genomes determine the when and where of gene expression during development. Here we discuss insights into the genetic and molecular mechanisms behind cis-regulatory module usage that have come from recent application of genomics assays to insect metamorphosis. Assays including FAIRE-seq, ATAC-seq, and CUT&RUN indicate that sequential changes in chromatin accessibility play a key role in mediating stage-specific cis-regulatory module activity and gene expression. We review the current understanding of what controls precisely coordinated changes in chromatin accessibility during metamorphosis and describe evidence that points to systemic hormone signaling as a primary signal to trigger genome-wide shifts in accessibility patterns and cis-regulatory module usage.
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Affiliation(s)
- Matthew J Niederhuber
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States
| | - Daniel J McKay
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States.
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34
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Mazina MY, Kovalenko EV, Vorobyeva NE. The negative elongation factor NELF promotes induced transcriptional response of Drosophila ecdysone-dependent genes. Sci Rep 2021; 11:172. [PMID: 33420323 PMCID: PMC7794308 DOI: 10.1038/s41598-020-80650-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/24/2020] [Indexed: 12/21/2022] Open
Abstract
For many years it was believed that promoter-proximal RNA-polymerase II (Pol II) pausing manages the transcription of genes in Drosophila development by controlling spatiotemporal properties of their activation and repression. But the exact proteins that cooperate to stall Pol II in promoter-proximal regions of developmental genes are still largely unknown. The current work describes the molecular mechanism employed by the Negative ELongation Factor (NELF) to control the Pol II pause at genes whose transcription is induced by 20-hydroxyecdysone (20E). According to our data, the NELF complex is recruited to the promoters and enhancers of 20E-dependent genes. Its presence at the regulatory sites of 20E-dependent genes correlates with observed interaction between the NELF-A subunit and the ecdysone receptor (EcR). The complete NELF complex is formed at the 20E-dependent promoters and participates in both their induced transcriptional response and maintenance of the uninduced state to keep them ready for the forthcoming transcription. NELF depletion causes a significant decrease in transcription induced by 20E, which is associated with the disruption of Pol II elongation complexes. A considerable reduction in the promoter-bound level of the Spt5 subunit of transcription elongation factor DSIF was observed at the 20E-dependent genes upon NELF depletion. We presume that an important function of NELF is to participate in stabilizing the Pol II-DSIF complex, resulting in a significant impact on transcription of its target genes. In order to directly link NELF to regulation of 20E-dependent genes in development, we show the presence of NELF at the promoters of 20E-dependent genes during their active transcription in both embryogenesis and metamorphosis. We also demonstrate that 20E-dependent promoters, while temporarily inactive at the larval stage, preserve a Pol II paused state and bind NELF complex.
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Affiliation(s)
- Marina Yu Mazina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Elena V Kovalenko
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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35
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Finger DS, Whitehead KM, Phipps DN, Ables ET. Nuclear receptors linking physiology and germline stem cells in Drosophila. VITAMINS AND HORMONES 2021; 116:327-362. [PMID: 33752824 PMCID: PMC8063499 DOI: 10.1016/bs.vh.2020.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Maternal nutrition and physiology are intimately associated with reproductive success in diverse organisms. Despite decades of study, the molecular mechanisms linking maternal diet to the production and quality of oocytes remain poorly defined. Nuclear receptors (NRs) link nutritional signals to cellular responses and are essential for oocyte development. The fruit fly, Drosophila melanogaster, is an excellent genetically tractable model to study the relationship between NR signaling and oocyte production. In this review, we explore how NRs in Drosophila regulate the earliest stages of oocyte development. Long-recognized as an essential mediator of developmental transitions, we focus on the intrinsic roles of the Ecdysone Receptor and its ligand, ecdysone, in oogenesis. We also review recent studies suggesting broader roles for NRs as regulators of maternal physiology and their impact specifically on oocyte production. We propose that NRs form the molecular basis of a broad physiological surveillance network linking maternal diet with oocyte production. Given the functional conservation between Drosophila and humans, continued experimental investigation into the molecular mechanisms by which NRs promote oogenesis will likely aid our understanding of human fertility.
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Affiliation(s)
- Danielle S Finger
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Kaitlin M Whitehead
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Daniel N Phipps
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Elizabeth T Ables
- Department of Biology, East Carolina University, Greenville, NC, United States.
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36
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Kamsoi O, Belles X. E93-depleted adult insects preserve the prothoracic gland and molt again. Development 2020; 147:dev.190066. [PMID: 33077428 DOI: 10.1242/dev.190066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 10/13/2020] [Indexed: 01/05/2023]
Abstract
Insect metamorphosis originated around the middle Devonian, associated with the innovation of the final molt; this occurs after histolysis of the prothoracic gland (PG; which produces the molting hormone) in the first days of adulthood. We previously hypothesized that transcription factor E93 is crucial in the emergence of metamorphosis, because it triggers metamorphosis in extant insects. This work on the cockroach Blattella germanica reveals that E93 also plays a crucial role in the histolysis of PG, which fits the above hypothesis. Previous studies have shown that the transcription factor FTZ-F1 is essential for PG histolysis. We have found that FTZ-F1 depletion towards the end of the final nymphal instar downregulates the expression of E93, whereas E93-depleted nymphs molt to adults that retain a functional PG. Interestingly, these adults are able to molt again, which is exceptional in insects. The study of insects able to molt again in the adult stage may reveal clues about how nymphal epidermal cells definitively become adult cells, and whether it is possible to reverse this process.
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Affiliation(s)
- Orathai Kamsoi
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Maritim 37, 08003 Barcelona, Spain
| | - Xavier Belles
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Maritim 37, 08003 Barcelona, Spain
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Abstract
The evolution of insect metamorphosis is one of the most important sagas in animal history, transforming small, obscure soil arthropods into a dominant terrestrial group that has profoundly shaped the evolution of terrestrial life. The evolution of flight initiated the trajectory towards metamorphosis, favoring enhanced differences between juvenile and adult stages. The initial step modified postembryonic development, resulting in the nymph-adult differences characteristic of hemimetabolous species. The second step was to complete metamorphosis, holometaboly, and occurred by profoundly altering embryogenesis to produce a larval stage, the nymph becoming the pupa to accommodate the deferred development needed to make the adult. These changing life history patterns were intimately linked to two hormonal systems, the ecdysteroids and the juvenile hormones (JH), which function in both embryonic and postembryonic domains and control the stage-specifying genes Krüppel homolog 1 (Kr-h1), broad and E93. The ecdysteroids induce and direct molting through the ecdysone receptor (EcR), a nuclear hormone receptor with numerous targets including a conserved transcription factor network, the 'Ashburner cascade', which translates features of the ecdysteroid peak into the different phases of the molt. With the evolution of metamorphosis, ecdysteroids acquired a metamorphic function that exploited the repressor capacity of the unliganded EcR, making it a hormone-controlled gateway for the tissue development preceding metamorphosis. JH directs ecdysteroid action, controlling Kr-h1 expression which in turn regulates the other stage-specifying genes. JH appears in basal insect groups as their embryos shift from growth and patterning to differentiation. As a major portion of embryogenesis was deferred to postembryonic life with the evolution of holometaboly, JH also acquired a potent role in regulating postembryonic growth and development. Details of its involvement in broad expression and E93 suppression have been modified as life cycles became more complex and likely underlie some of the changes seen in the shift from incomplete to complete metamorphosis.
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Affiliation(s)
- James W Truman
- Department of Biology and Friday Harbor Laboratories, University of Washington, 620 University Road, Friday Harbor, WA 98250, USA.
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38
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Riddiford LM. Rhodnius, Golden Oil, and Met: A History of Juvenile Hormone Research. Front Cell Dev Biol 2020; 8:679. [PMID: 32850806 PMCID: PMC7426621 DOI: 10.3389/fcell.2020.00679] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/06/2020] [Indexed: 12/13/2022] Open
Abstract
Juvenile hormone (JH) is a unique sesquiterpenoid hormone which regulates both insect metamorphosis and insect reproduction. It also may be utilized by some insects to mediate polyphenisms and other life history events that are environmentally regulated. This article details the history of the research on this versatile hormone that began with studies by V. B. Wigglesworth on the "kissing bug" Rhodnius prolixus in 1934, through the discovery of a natural source of JH in the abdomen of male Hyalophora cecropia moths by C. M. Williams that allowed its isolation ("golden oil") and identification, to the recent research on its receptor, termed Methoprene-tolerant (Met). Our present knowledge of cellular actions of JH in metamorphosis springs primarily from studies on Rhodnius and the tobacco hornworm Manduca sexta, with recent studies on the flour beetle Tribolium castaneum, the silkworm Bombyx mori, and the fruit fly Drosophila melanogaster contributing to the molecular understanding of these actions. Many questions still need to be resolved including the molecular basis of competence to metamorphose, differential tissue responses to JH, and the interaction of nutrition and other environmental signals regulating JH synthesis and degradation.
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Affiliation(s)
- Lynn M Riddiford
- Department of Biology, Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, United States
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van der Burg KRL, Lewis JJ, Martin A, Nijhout HF, Danko CG, Reed RD. Contrasting Roles of Transcription Factors Spineless and EcR in the Highly Dynamic Chromatin Landscape of Butterfly Wing Metamorphosis. Cell Rep 2020; 27:1027-1038.e3. [PMID: 31018121 DOI: 10.1016/j.celrep.2019.03.092] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 02/22/2019] [Accepted: 03/25/2019] [Indexed: 01/24/2023] Open
Abstract
Development requires highly coordinated changes in chromatin accessibility in order for proper gene regulation to occur. Here, we identify factors associated with major, discrete changes in chromatin accessibility during butterfly wing metamorphosis. By combining mRNA sequencing (mRNA-seq), assay for transposase-accessible chromatin using sequencing (ATAC-seq), and machine learning analysis of motifs, we show that distinct sets of transcription factors are predictive of chromatin opening at different developmental stages. Our data suggest an important role for nuclear hormone receptors early in metamorphosis, whereas PAS-domain transcription factors are strongly associated with later chromatin opening. Chromatin immunoprecipitation sequencing (ChIP-seq) validation of select candidate factors showed spineless binding to be a major predictor of opening chromatin. Surprisingly, binding of ecdysone receptor (EcR), a candidate accessibility factor in Drosophila, was not predictive of opening but instead marked persistent sites. This work characterizes the chromatin dynamics of insect wing metamorphosis, identifies candidate chromatin remodeling factors in insects, and presents a genome assembly of the model butterfly Junonia coenia.
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Affiliation(s)
- Karin R L van der Burg
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.
| | - James J Lewis
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA; Baker Institute for Animal Health, Cornell University, Ithaca, NY 14853, USA
| | - Arnaud Martin
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | | | - Charles G Danko
- Baker Institute for Animal Health, Cornell University, Ithaca, NY 14853, USA
| | - Robert D Reed
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
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Harris RE, Stinchfield MJ, Nystrom SL, McKay DJ, Hariharan IK. Damage-responsive, maturity-silenced enhancers regulate multiple genes that direct regeneration in Drosophila. eLife 2020; 9:58305. [PMID: 32490812 PMCID: PMC7299344 DOI: 10.7554/elife.58305] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/28/2020] [Indexed: 12/31/2022] Open
Abstract
Like tissues of many organisms, Drosophila imaginal discs lose the ability to regenerate as they mature. This loss of regenerative capacity coincides with reduced damage-responsive expression of multiple genes needed for regeneration. We previously showed that two such genes, wg and Wnt6, are regulated by a single damage-responsive enhancer that becomes progressively inactivated via Polycomb-mediated silencing as discs mature (Harris et al., 2016). Here we explore the generality of this mechanism and identify additional damage-responsive, maturity-silenced (DRMS) enhancers, some near genes known to be required for regeneration such as Mmp1, and others near genes that we now show function in regeneration. Using a novel GAL4-independent ablation system we characterize two DRMS-associated genes, apontic (apt), which curtails regeneration and CG9752/asperous (aspr), which promotes it. This mechanism of suppressing regeneration by silencing damage-responsive enhancers at multiple loci can be partially overcome by reducing activity of the chromatin regulator extra sex combs (esc).
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Affiliation(s)
| | | | - Spencer L Nystrom
- University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Daniel J McKay
- University of North Carolina at Chapel Hill, Chapel Hill, United States
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Abstract
Drosophila melanogaster has historically been a workhorse model organism for studying developmental biology. In addition, Drosophila is an excellent model for studying how damaged tissues and organs can regenerate. Recently, new precision approaches that enable both highly targeted injury and genetic manipulation have accelerated progress in this field. Here, we highlight these techniques and review examples of recently discovered mechanisms that regulate regeneration in Drosophila larval and adult tissues. We also discuss how, by applying these powerful approaches, studies of Drosophila can continue to guide the future of regeneration research.
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Affiliation(s)
- Donald T Fox
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
- Regeneration Next, Duke University, Durham, NC 27710, USA
| | - Erez Cohen
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
- Regeneration Next, Duke University, Durham, NC 27710, USA
| | - Rachel Smith-Bolton
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Proximity-dependent biotin labelling reveals CP190 as an EcR/Usp molecular partner. Sci Rep 2020; 10:4793. [PMID: 32179799 PMCID: PMC7075897 DOI: 10.1038/s41598-020-61514-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/28/2020] [Indexed: 11/23/2022] Open
Abstract
Proximity-dependent biotin labelling revealed undescribed participants of the ecdysone response in Drosophila. Two labelling enzymes (BioID2 and APEX2) were fused to EcR or Usp to biotin label the surrounding proteins. The EcR/Usp heterodimer was found to collaborate with nuclear pore subunits, chromatin remodelers, and architectural proteins. Many proteins identified through proximity-dependent labelling with EcR/Usp were described previously as functional components of an ecdysone response, corroborating the potency of this labelling method. A link to ecdysone response was confirmed for some newly discovered regulators by immunoprecipitation of prepupal nuclear extract with anti-EcR antibodies and functional experiments in Drosophila S2 cells. A more in-depth study was conducted to clarify the association of EcR/Usp with one of the detected proteins, CP190, a well-described cofactor of Drosophila insulators. CP190 was found to co-immunoprecipitate with the EcR subunit of EcR/Usp in a 20E-independent manner. ChIP-Seq experiments revealed only partial overlapping between CP190 and EcR bound sites in the Drosophila genome and complete absence of CP190 binding at 20E-dependent enhancers. Analysis of Hi-C data demonstrated an existence of remote interactions between 20E-dependent enhancers and CP190 sites which suggests formation of a protein complex between EcR/Usp and CP190 through the space. Our results support the previous concept that CP190 has a role in stabilization of specific chromatin loops for proper activation of transcription of genes regulated by 20E hormone.
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Nystrom SL, Niederhuber MJ, McKay DJ. Expression of E93 provides an instructive cue to control dynamic enhancer activity and chromatin accessibility during development. Development 2020; 147:dev181909. [PMID: 32094114 PMCID: PMC7097197 DOI: 10.1242/dev.181909] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 02/10/2020] [Indexed: 12/14/2022]
Abstract
How temporal cues combine with spatial inputs to control gene expression during development is poorly understood. Here, we test the hypothesis that the Drosophila transcription factor E93 controls temporal gene expression by regulating chromatin accessibility. Precocious expression of E93 early in wing development reveals that it can simultaneously activate and deactivate different target enhancers. Notably, the precocious patterns of enhancer activity resemble the wild-type patterns that occur later in development, suggesting that expression of E93 alters the competence of enhancers to respond to spatial cues. Genomic profiling reveals that precocious E93 expression is sufficient to regulate chromatin accessibility at a subset of its targets. These accessibility changes mimic those that normally occur later in development, indicating that precocious E93 accelerates the wild-type developmental program. Further, we find that target enhancers that do not respond to precocious E93 in early wings become responsive after a developmental transition, suggesting that parallel temporal pathways work alongside E93. These findings support a model wherein E93 expression functions as an instructive cue that defines a broad window of developmental time through control of chromatin accessibility.
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Affiliation(s)
- Spencer L Nystrom
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Matthew J Niederhuber
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Daniel J McKay
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Bozek M, Gompel N. Developmental Transcriptional Enhancers: A Subtle Interplay between Accessibility and Activity: Considering Quantitative Accessibility Changes between Different Regulatory States of an Enhancer Deconvolutes the Complex Relationship between Accessibility and Activity. Bioessays 2020; 42:e1900188. [PMID: 32142172 DOI: 10.1002/bies.201900188] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/16/2020] [Indexed: 12/21/2022]
Abstract
Measurements of open chromatin in specific cell types are widely used to infer the spatiotemporal activity of transcriptional enhancers. How reliable are these predictions? In this review, it is argued that the relationship between the accessibility and activity of an enhancer is insufficiently described by simply considering open versus closed chromatin, or active versus inactive enhancers. Instead, recent studies focusing on the quantitative nature of accessibility signal reveal subtle differences between active enhancers and their different inactive counterparts: the closed silenced state and the accessible primed and repressed states. While the open structure as such is not a specific indicator of enhancer activity, active enhancers display a higher degree of accessibility than the primed and repressed states. Molecular mechanisms that may account for these quantitative differences are discussed. A model that relates molecular events at an enhancer to changes in its activity and accessibility in a developing tissue is also proposed.
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Affiliation(s)
- Marta Bozek
- Department Biochemie, Ludwig-Maximilians Universität München, Genzentrum, 81377, München, Germany
| | - Nicolas Gompel
- Fakultät für Biologie, Ludwig-Maximilians Universität München, Biozentrum, 82152, Planegg-Martinsried, Germany
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Belles X. Krüppel homolog 1 and E93: The doorkeeper and the key to insect metamorphosis. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2020; 103:e21609. [PMID: 31385626 DOI: 10.1002/arch.21609] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/18/2019] [Accepted: 07/23/2019] [Indexed: 06/10/2023]
Abstract
Insect metamorphosis is regulated by two main hormones: ecdysone (20E), which promotes molting, and juvenile hormone (JH), which inhibits adult morphogenesis. The transduction mechanisms for the respective hormonal signals include the transcription factors Krüppel homolog 1 (Kr-h1) and E93, which are JH- and 20E-dependent, respectively. Kr-h1 is the main effector of the antimetamorphic action of JH, while E93 is a key promoter of metamorphosis. The ancestral regulatory axis of metamorphosis, which operates in insects with hemimetabolan (gradual) metamorphosis and is known as the MEKRE93 pathway, is based on Kr-h1 repression of E93. In the last juvenile stage, when the production of JH dramatically decreases, Kr-h1 expression is almost completely interrupted, E93 becomes upregulated and metamorphosis proceeds. The holometabolan (complete) metamorphosis mode of development includes the peculiar pupal stage, a sort of intermediate between the final larval instar and the adult stage. In holometabolan species, Broad-Complex (BR-C) transcription factors determine the pupal stage and E93 stimulates the expression of BR-C in the prepupa. The MEKRE93 pathway is conserved in holometabolan insects, which have added the E93/BR-C interaction loop to the ancestral (hemimetabolan) pathway during the evolution from hemimetaboly to holometaboly.
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Affiliation(s)
- Xavier Belles
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
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46
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Ma Y, McKay DJ, Buttitta L. Changes in chromatin accessibility ensure robust cell cycle exit in terminally differentiated cells. PLoS Biol 2019; 17:e3000378. [PMID: 31479438 PMCID: PMC6743789 DOI: 10.1371/journal.pbio.3000378] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 09/13/2019] [Accepted: 08/13/2019] [Indexed: 12/12/2022] Open
Abstract
During terminal differentiation, most cells exit the cell cycle and enter into a prolonged or permanent G0 in which they are refractory to mitogenic signals. Entry into G0 is usually initiated through the repression of cell cycle gene expression by formation of a transcriptional repressor complex called dimerization partner (DP), retinoblastoma (RB)-like, E2F and MuvB (DREAM). However, when DREAM repressive function is compromised during terminal differentiation, additional unknown mechanisms act to stably repress cycling and ensure robust cell cycle exit. Here, we provide evidence that developmentally programmed, temporal changes in chromatin accessibility at a small subset of critical cell cycle genes act to enforce cell cycle exit during terminal differentiation in the Drosophila melanogaster wing. We show that during terminal differentiation, chromatin closes at a set of pupal wing enhancers for the key rate-limiting cell cycle regulators Cyclin E (cycE), E2F transcription factor 1 (e2f1), and string (stg). This closing coincides with wing cells entering a robust postmitotic state that is strongly refractory to cell cycle reactivation, and the regions that close contain known binding sites for effectors of mitogenic signaling pathways such as Yorkie and Notch. When cell cycle exit is genetically disrupted, chromatin accessibility at cell cycle genes remains unaffected, and the closing of distal enhancers at cycE, e2f1, and stg proceeds independent of the cell cycling status. Instead, disruption of cell cycle exit leads to changes in accessibility and expression of a subset of hormone-induced transcription factors involved in the progression of terminal differentiation. Our results uncover a mechanism that acts as a cell cycle–independent timer to limit the response to mitogenic signaling and aberrant cycling in terminally differentiating tissues. In addition, we provide a new molecular description of the cross talk between cell cycle exit and terminal differentiation during metamorphosis. The longer a cell remains in G0, the more refractory it becomes to re-entering the cell cycle. This study shows that in terminally differentiated cells in vivo, regulatory elements at genes encoding just three key cell cycle regulators (cycE, e2f1 and stg) become inaccessible, limiting their aberrant activation and maintaining a prolonged, robust G0.
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Affiliation(s)
- Yiqin Ma
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Daniel J McKay
- Department of Biology, Department of Genetics, Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Laura Buttitta
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
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47
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Belles X. The innovation of the final moult and the origin of insect metamorphosis. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180415. [PMID: 31438822 DOI: 10.1098/rstb.2018.0415] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The three modes of insect postembryonic development are ametaboly, hemimetaboly and holometaboly, the latter being considered the only significant metamorphosis mode. However, the emergence of hemimetaboly, with the genuine innovation of the final moult, represents the origin of insect metamorphosis and a necessary step in the evolution of holometaboly. Hemimetaboly derives from ametaboly and might have appeared as a consequence of wing emergence in Pterygota, in the early Devonian. In extant insects, the final moult is mainly achieved through the degeneration of the prothoracic gland (PG), after the formation of the winged and reproductively competent adult stage. Metamorphosis, including the formation of the mature wings and the degeneration of the PG, is regulated by the MEKRE93 pathway, through which juvenile hormone precludes the adult morphogenesis by repressing the expression of transcription factor E93, which triggers this change. The MEKRE93 pathway appears conserved in extant metamorphosing insects, which suggest that this pathway was operative in the Pterygota last common ancestor. We propose that the final moult, and the consequent hemimetabolan metamorphosis, is a monophyletic innovation and that the role of E93 as a promoter of wing formation and the degeneration of the PG was mechanistically crucial for their emergence. This article is part of the theme issue 'The evolution of complete metamorphosis'.
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Affiliation(s)
- Xavier Belles
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Maritim 37, 08003 Barcelona, Spain
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48
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Truman JW, Riddiford LM. The evolution of insect metamorphosis: a developmental and endocrine view. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190070. [PMID: 31438820 PMCID: PMC6711285 DOI: 10.1098/rstb.2019.0070] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Developmental, genetic and endocrine data from diverse taxa provide insight into the evolution of insect metamorphosis. We equate the larva–pupa–adult of the Holometabola to the pronymph–nymph–adult of hemimetabolous insects. The hemimetabolous pronymph is a cryptic embryonic stage with unique endocrinology and behavioural modifications that probably served as preadaptations for the larva. It develops in the absence of juvenile hormone (JH) as embryonic primordia undergo patterning and morphogenesis, the processes that were arrested for the evolution of the larva. Embryonic JH then drives tissue differentiation and nymph formation. Experimental treatment of pronymphs with JH terminates patterning and induces differentiation, mimicking the processes that occurred during the evolution of the larva. Unpatterned portions of primordia persist in the larva, becoming imaginal discs that form pupal and adult structures. Key transcription factors are associated with the holometabolous life stages: Krüppel-homolog 1 (Kr-h1) in the larva, broad in the pupa and E93 in the adult. Kr-h1 mediates JH action and is found whenever JH acts, while the other two genes direct the formation of their corresponding stages. In hemimetabolous forms, the pronymph has low Broad expression, followed by Broad expression through the nymphal moults, then a switch to E93 to form the adult. This article is part of the theme issue ‘The evolution of complete metamorphosis’.
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Affiliation(s)
- James W Truman
- Department of Biology, Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
| | - Lynn M Riddiford
- Department of Biology, Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
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49
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Lee HK, Willi M, Shin HY, Liu C, Hennighausen L. Progressing super-enhancer landscape during mammary differentiation controls tissue-specific gene regulation. Nucleic Acids Res 2019; 46:10796-10809. [PMID: 30285185 PMCID: PMC6237736 DOI: 10.1093/nar/gky891] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 09/20/2018] [Indexed: 12/15/2022] Open
Abstract
The mammary luminal lineage relies on the common cytokine-sensing transcription factor STAT5 to establish super-enhancers during pregnancy and initiate a genetic program that activates milk production. As pups grow, the greatly increasing demand for milk requires progressive differentiation of mammary cells with advancing lactation. Here we investigate how persistent hormonal exposure during lactation shapes an evolving enhancer landscape and impacts the biology of mammary cells. Employing ChIP-seq, we uncover a changing transcription factor occupancy at mammary enhancers, suggesting that their activities evolve with advancing differentiation. Using mouse genetics, we demonstrate that the functions of individual enhancers within the Wap super-enhancer evolve as lactation progresses. Most profoundly, a seed enhancer, which is mandatory for the activation of the Wap super-enhancer during pregnancy, is not required during lactation, suggesting compensatory flexibility. Combinatorial deletions of structurally equivalent constituent enhancers demonstrated differentiation-specific compensatory activities during lactation. We also demonstrate that the Wap super-enhancer, which is built on STAT5 and other common transcription factors, retains its exquisite mammary specificity when placed into globally permissive chromatin, suggesting a limited role of chromatin in controlling cell specificity. Our studies unveil a previously unrecognized progressive enhancer landscape where structurally equivalent components serve unique and differentiation-specific functions.
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Affiliation(s)
- Hye Kyung Lee
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, MD 20892, USA
| | - Michaela Willi
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, MD 20892, USA
| | - Ha Youn Shin
- Department of Biomedical Science and Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Chengyu Liu
- Transgenic Core, National Heart, Lung, and Blood Institute, US National Institutes of Health, Bethesda, MD 20892, USA
| | - Lothar Hennighausen
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, MD 20892, USA
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50
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Talbert PB, Meers MP, Henikoff S. Old cogs, new tricks: the evolution of gene expression in a chromatin context. Nat Rev Genet 2019; 20:283-297. [PMID: 30886348 DOI: 10.1038/s41576-019-0105-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Sophisticated gene-regulatory mechanisms probably evolved in prokaryotes billions of years before the emergence of modern eukaryotes, which inherited the same basic enzymatic machineries. However, the epigenomic landscapes of eukaryotes are dominated by nucleosomes, which have acquired roles in genome packaging, mitotic condensation and silencing parasitic genomic elements. Although the molecular mechanisms by which nucleosomes are displaced and modified have been described, just how transcription factors, histone variants and modifications and chromatin regulators act on nucleosomes to regulate transcription is the subject of considerable ongoing study. We explore the extent to which these transcriptional regulatory components function in the context of the evolutionarily ancient role of chromatin as a barrier to processes acting on DNA and how chromatin proteins have diversified to carry out evolutionarily recent functions that accompanied the emergence of differentiation and development in multicellular eukaryotes.
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Affiliation(s)
- Paul B Talbert
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Michael P Meers
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Steven Henikoff
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
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