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1.
Proc Natl Acad Sci U S A ; 119(25): e2202932119, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35696563

RESUMO

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.


Assuntos
Aedes , Ecdisona , Proteínas de Insetos , Transportadores de Ânions Orgânicos , Aedes/crescimento & desenvolvimento , Aedes/fisiologia , Animais , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Ecdisona/metabolismo , Feminino , Proteínas de Insetos/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Vitelogênese
2.
Insect Biochem Mol Biol ; 145: 103784, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35533806

RESUMO

The heterochronic microRNA let-7, which was first identified in Caenorhabditis elegans, controls the timing of developmental programs, and let-7 triggers the onset of the juvenile-adult transition in bilaterians. The expression of let-7 is strongly induced during the last larval stage of C. elegans and is highly expressed in the late last instar larvae/nymphs of the fly Drosophila melanogaster and the cockroach Blattella germanica. In the silkworm Bombyx mori, the expression of let-7 remarkably increases in the corpus cardiacum-corpus allatum complex (CC-CA) at the beginning of the last larval instar and is maintained at high levels during this instar. To determine the biological function of let-7 in B. mori, we generated a let-7 knockout line and a transgenic UAS-let-7 line. The let-7 knockout larvae were developmentally arrested in the prepupal stage and became pupal-adult intermediates after apolysis. When let-7 was ubiquitously overexpressed under the transcriptional control of an Actin3-GAL4 driver, developmental timing and growth of larvae were severely impaired in the penultimate (L4) instar, and these larvae underwent precocious metamorphosis from L4. Furthermore, our results showed that reception and signaling of ecdysteroids and juvenile hormones (JHs) normally occurred in the absence of let-7, whereas the biosynthesis of ecdysone and JHs were affected by disruption and overexpression of let-7. Together, the present study demonstrates that let-7 is required for the coordination of the biosynthesis of ecdysone and JH to ensure the developmental transition during the metamorphosis of B. mori.


Assuntos
Bombyx , MicroRNAs , Animais , Bombyx/metabolismo , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Drosophila melanogaster/metabolismo , Ecdisona/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Hormônios Juvenis/metabolismo , Larva , Metamorfose Biológica/genética , MicroRNAs/genética , MicroRNAs/metabolismo
3.
Curr Biol ; 32(10): 2341-2348.e3, 2022 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-35508173

RESUMO

While we think of neurons as having a fixed identity, many show spectacular plasticity.1-10 Metamorphosis drives massive changes in the fly brain;11,12 neurons that persist into adulthood often change in response to the steroid hormone ecdysone.13,14 Besides driving remodeling,11-14 ecdysone signaling can also alter the differentiation status of neurons.7,15 The three sequentially born subtypes of mushroom body (MB) Kenyon cells (γ, followed by α'/ß', and finally α/ß)16 serve as a model of temporal fating.17-21 γ neurons are also used as a model of remodeling during metamorphosis. As γ neurons are the only functional Kenyon cells in the larval brain, they serve the function of all three adult subtypes. Correspondingly, larval γ neurons have a similar morphology to α'/ß' and α/ß neurons-their axons project dorsally and medially. During metamorphosis, γ neurons remodel to form a single medial projection. Both temporal fate changes and defects in remodeling therefore alter γ-neuron morphology in similar ways. Mamo, a broad-complex, tramtrack, and bric-à-brac/poxvirus and zinc finger (BTB/POZ) transcription factor critical for temporal specification of α'/ß' neurons,18,19 was recently described as essential for γ remodeling.22 In a previous study, we noticed a change in the number of adult Kenyon cells expressing γ-specific markers when mamo was manipulated.18 These data implied a role for Mamo in γ-neuron fate specification, yet mamo is not expressed in γ neurons until pupariation,18,22 well past γ specification. This indicates that mamo has a later role in ensuring that γ neurons express the correct Kenyon cell subtype-specific genes in the adult brain.


Assuntos
Ecdisona , Corpos Pedunculados , Animais , Axônios , Diferenciação Celular , Larva , Corpos Pedunculados/fisiologia , Neurônios/fisiologia
4.
Elife ; 112022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35353036

RESUMO

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.


During their lives, animals encounter a broad range of stimuli from their surroundings including heat, light and touch. The ability to appropriately respond to such stimuli is crucial for survival as it allows the animals to avoid predators and other dangers, locate food and shelter, and find mates. Fruit fly larvae are a useful model for studying how animals respond to unpleasant (known as painful) heat stimuli. When something hot touches a larva, the larva rolls away to avoid the stimulus. The heat stimulates electrical activity in a type of neuron known as C4da neurons on the surface of the larva. Ultraviolet light and several other stimuli are also able to activate electrical activity in C4da neurons, resulting in the larvae changing the direction they move to avoid the stimuli. Only older fly larvae respond to painful heat stimuli and previous studies found that a hormone receptor protein is required for this response. However, it remains unclear how this response develops as the larvae age. Jaszczak et al. studied the behavior of fly larvae and electrical activities of C4da neurons in response to painful heat and ultraviolet light. The experiments found that painful heat triggered more rolling behavior from older larvae than those of younger larvae. In contrast, ultraviolet light triggered lower levels of electrical activity in the C4da neurons of older larvae than those of younger larvae. The team raised the levels of a hormone known as ecdysone and found that this increased the rolling behavior in younger larvae. They then increased the amount of receptor protein for this hormone in the neurons and found that it decreased the levels of another protein called Subdued in the C4da neurons. This in turn increased the neurons' response to painful heat and decreased their response to ultraviolet light. Jaszczak et al. propose that as the larva develops, ecdysone reduces the levels of Subdued, which promotes C4da neurons to switch their sensitivity from detecting ultraviolet light to painful heat. In the future, better understanding of what causes pain sensations in developing animals will help us search for factors that cause long-term pain conditions in humans.


Assuntos
Drosophila melanogaster , Drosophila , Animais , Drosophila/fisiologia , Drosophila melanogaster/metabolismo , Ecdisona/metabolismo , Nociceptividade/fisiologia , Células Receptoras Sensoriais/metabolismo
5.
Development ; 149(7)2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35297965

RESUMO

The formation of a functional organ such as the eye requires specification of the correct cell types and their terminal differentiation into cells with the appropriate morphologies and functions. Here, we show that the zinc-finger transcription factor Blimp-1 acts in secondary and tertiary pigment cells in the Drosophila retina to promote the formation of a bi-convex corneal lens with normal refractive power, and in cone cells to enable complete extension of the photoreceptor rhabdomeres. Blimp-1 expression depends on the hormone ecdysone, and loss of ecdysone signaling causes similar differentiation defects. Timely termination of Blimp-1 expression is also important, as its overexpression in the eye has deleterious effects. Our transcriptomic analysis revealed that Blimp-1 regulates the expression of many structural and secreted proteins in the retina. Blimp-1 may function in part by repressing another transcription factor; Slow border cells is highly upregulated in the absence of Blimp-1, and its overexpression reproduces many of the effects of removing Blimp-1. This work provides insight into the transcriptional networks and cellular interactions that produce the structures necessary for visual function.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Drosophila/genética , Proteínas de Drosophila/genética , Ecdisona , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Proteínas Repressoras/genética , Fatores de Transcrição/genética
6.
Curr Biol ; 32(8): 1788-1797.e5, 2022 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-35316653

RESUMO

Insulin/insulin-like growth factor (IGF) signaling (IIS) controls many aspects of development and physiology. In Drosophila, a conserved family of insulin-like peptides called Dilps is produced by brain neurosecretory cells, and it regulates organismal growth and developmental timing. To accomplish these systemic functions, the Dilps are secreted into the general circulation, and they signal to peripheral tissues in an endocrine fashion. Here, we describe the local uptake and storage of Dilps in the corpora cardiaca (CC), an endocrine organ composed of alpha cell homologs known to produce the glucagon-like adipokinetic hormone (AKH). We show that Dilp uptake by the CC relies on the expression of an IGF-binding protein called ImpL2. Following their uptake, immunogold staining demonstrates that Dilps are co-packaged with AKH in dense-core vesicles for secretion. In response to nutrient shortage, this specific Dilp reservoir is released and activates IIS in a paracrine manner in the prothoracic gland. This stimulates the production of the steroid hormone ecdysone and initiates entry into pupal development. We therefore uncover a sparing mechanism whereby insulin stores in CC serve to locally activate IIS and the production of ecdysone in the PG, accelerating developmental progression in adverse food conditions.


Assuntos
Proteínas de Drosophila , Somatomedinas , Animais , Drosophila/fisiologia , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Ecdisona/metabolismo , Insulina/metabolismo , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/metabolismo , Larva/metabolismo , Nutrientes , Somatomedinas/metabolismo
7.
Elife ; 112022 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-35261337

RESUMO

Animals develop in unpredictable, variable environments. In response to environmental change, some aspects of development adjust to generate plastic phenotypes. Other aspects of development, however, are buffered against environmental change to produce robust phenotypes. How organ development is coordinated to accommodate both plastic and robust developmental responses is poorly understood. Here, we demonstrate that the steroid hormone ecdysone coordinates both plasticity of organ size and robustness of organ pattern in the developing wings of the fruit fly Drosophila melanogaster. Using fed and starved larvae that lack prothoracic glands, which synthesize ecdysone, we show that nutrition regulates growth both via ecdysone and via an ecdysone-independent mechanism, while nutrition regulates patterning only via ecdysone. We then demonstrate that growth shows a graded response to ecdysone concentration, while patterning shows a threshold response. Collectively, these data support a model where nutritionally regulated ecdysone fluctuations confer plasticity by regulating disc growth in response to basal ecdysone levels and confer robustness by initiating patterning only once ecdysone peaks exceed a threshold concentration. This could represent a generalizable mechanism through which hormones coordinate plastic growth with robust patterning in the face of environmental change.


Assuntos
Proteínas de Drosophila , Ecdisona , Animais , Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Regulação da Expressão Gênica no Desenvolvimento , Larva , Plásticos , Transdução de Sinais/genética
8.
Elife ; 112022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35289742

RESUMO

Cellular ability to mount an enhanced transcriptional response upon repeated exposure to external cues is termed transcriptional memory, which can be maintained epigenetically through cell divisions and can depend on a nuclear pore component Nup98. The majority of mechanistic knowledge on transcriptional memory has been derived from bulk molecular assays. To gain additional perspective on the mechanism and contribution of Nup98 to memory, we used single-molecule RNA FISH (smFISH) to examine the dynamics of transcription in Drosophila cells upon repeated exposure to the steroid hormone ecdysone. We combined smFISH with mathematical modeling and found that upon hormone exposure, cells rapidly activate a low-level transcriptional response, but simultaneously begin a slow transition into a specialized memory state characterized by a high rate of expression. Strikingly, our modeling predicted that this transition between non-memory and memory states is independent of the transcription stemming from initial activation. We confirmed this prediction experimentally by showing that inhibiting transcription during initial ecdysone exposure did not interfere with memory establishment. Together, our findings reveal that Nup98's role in transcriptional memory is to stabilize the forward rate of conversion from low to high expressing state, and that induced genes engage in two separate behaviors - transcription itself and the establishment of epigenetically propagated transcriptional memory.


Assuntos
Proteínas de Drosophila , Ecdisona , Animais , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Ecdisona/metabolismo , Poro Nuclear/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Transcrição Genética , Translocação Genética
9.
Sci Rep ; 12(1): 4730, 2022 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-35304878

RESUMO

In almost all animals, physiologically low oxygen (hypoxia) during development slows growth and reduces adult body size. The developmental mechanisms that determine growth under hypoxic conditions are, however, poorly understood. Here we show that the growth and body size response to moderate hypoxia (10% O2) in Drosophila melanogaster is systemically regulated via the steroid hormone ecdysone. Hypoxia increases level of circulating ecdysone and inhibition of ecdysone synthesis ameliorates the negative effect of low oxygen on growth. We also show that the effect of ecdysone on growth under hypoxia is through suppression of the insulin/IGF-signaling pathway, via increased expression of the insulin-binding protein Imp-L2. These data indicate that growth suppression in hypoxic Drosophila larvae is accomplished by a systemic endocrine mechanism that overlaps with the mechanism that slows growth at low nutrition. This suggests the existence of growth-regulatory mechanisms that respond to general environmental perturbation rather than individual environmental factors.


Assuntos
Proteínas de Drosophila , Ecdisona , Animais , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Ecdisona/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Hipóxia , Insulina/metabolismo , Larva/fisiologia , Oxigênio/metabolismo , Esteroides/metabolismo
10.
Proc Natl Acad Sci U S A ; 119(11): e2116787119, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35254892

RESUMO

SignificanceHematophagous Aedes aegypti mosquitoes spread devastating viral diseases. Upon blood feeding, a steroid hormone, 20-hydroxyecdysone (20E), initiates a reproductive program during which thousands of genes are differentially expressed. While 20E-mediated gene activation is well known, repressive action by this hormone remains poorly understood. Using bioinformatics and molecular biological approaches, we have identified the mechanisms of 20E-dependent direct and indirect transcriptional repression by the ecdysone receptor (EcR). While indirect repression involves E74, EcR binds to an ecdysone response element different from those utilized in 20E-mediated gene activation to exert direct repressive action. Moreover, liganded EcR recruits a corepressor Mi2, initiating chromatin compaction. This study advances our understanding of the 20E-EcR repression mechanism and could lead to improved vector control approaches.


Assuntos
Ecdisona/metabolismo , Regulação da Expressão Gênica , Mosquitos Vetores/genética , Mosquitos Vetores/metabolismo , Reprodução/genética , Sítios de Ligação , Ecdisterona/metabolismo , Genes Reporter , Especificidade de Órgãos , Regiões Promotoras Genéticas , Ligação Proteica , Receptores de Esteroides/metabolismo , Fatores de Transcrição/metabolismo
11.
Dev Biol ; 485: 70-79, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35248548

RESUMO

Caste development in social insects requires the coordination of molting and metamorphosis during postembryonic development. In termites, i.e., hemimetabolous eusocial insects, caste fate is determined during postembryonic development. However, it is not fully understood how the mechanisms of molting/metamorphosis are regulated in the course of differentiation between reproductive and sterile castes. In termites, only reproductives derived from alates are imagos and other sterile castes (including developmentally-terminal soldier caste) are basically juveniles or nymphs. Furthermore, supplementary reproductives that appear when the original queens and kings die or become senescent, exhibit larval features such as winglessness, and are called neotenics. Therefore, the question of whether neotenics are larvae or imagos is still under debate. In this study, by inducing female neotenic differentiation in a damp-wood termite Hodotermopsis sjostedti, morphological investigations together with juvenile hormone (JH) quantification and expression/functional analyses of genes responsible for molting and/or metamorphosis were carried out. JH titer and expression of one of the downstream genes (Kr-h1) were shown to be temporarily lowered, but increased just prior to the molt into neotenics, while consistently lowered in imaginal molt (i.e., alate differentiation). In contrast, ecdysone-related genes (EcR and E93) were upregulated at both neotenic and alate differentiation, suggesting that the heterochronic actions of ecdysone and JH lead the neotenic differentiation. Moreover, expression analyses, supported by reverse genetic experiments, showed that EcR and E93 were specifically upregulated in genital sternites (EcR and E93) and ovaries (E93) and required for the development of imaginal characters. These results suggest that the resultant mosaic phenotype of female neotenics is due to modular responses of different body parts to hormonal actions.


Assuntos
Isópteros , Animais , Ecdisona/metabolismo , Feminino , Isópteros/genética , Isópteros/metabolismo , Hormônios Juvenis/metabolismo , Muda/genética , Diferenciação Sexual
12.
Proc Natl Acad Sci U S A ; 119(11): e2118871119, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35259020

RESUMO

SignificanceJuvenile hormone (JH), a sesquiterpenoid, regulates many aspects of insect development, including maintenance of the larval stage by preventing metamorphosis. In contrast, ecdysteroids promote metamorphosis by inducing the E93 transcription factor, which triggers apoptosis of larval cells and remodeling of the larval midgut. We discovered that JH suppresses precocious larval midgut-remodeling by inducing an epigenetic modifier, histone deacetylase 3 (HDAC3). JH-induced HDAC3 deacetylates the histone H4 localized at the promoters of proapoptotic genes, resulting in the suppression of these genes. This eventually prevents programmed cell death of midgut cells and midgut-remodeling during larval stages. These studies identified a previously unknown mechanism of JH action in blocking premature remodeling of the midgut during larval feeding stages.


Assuntos
Aedes/fisiologia , Apoptose , Sistema Digestório/metabolismo , Histona Desacetilases/metabolismo , Hormônios Juvenis/metabolismo , Animais , Apoptose/genética , Sistema Digestório/anatomia & histologia , Ecdisona/metabolismo , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Histona Desacetilases/genética , Histonas/metabolismo , Larva , Pupa/metabolismo
13.
Exp Parasitol ; 236-237: 108247, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35307367

RESUMO

Studies on the effects of azadirachtin treatment, ecdysone supplementation and ecdysone therapy on both the ultrastructural organization of the rectum in 5th-instar nymph of Rhodnius prolixus and the ex vivo attachment behavior of Trypanosoma cruzi under these experimental conditions were carried out. Control insects had a typical and significant organization of the rectum cuticle consisted of four main layers (procuticle, inner epicuticle, outer epicuticle, and wax layer) during the entire period of the experiment. Both azadirachtin treatment and ecdysone supplementation avoid the development of both outer epicuticle and wax layer. Oral therapy with ecdysone partially reversed the altered organization and induce the development of the four main rectal cuticle layers. In the same way, the ex vivo attachment of T. cruzi to rectal cuticle was blocked by azadirachtin treatment but ecdysone therapy also partially recovered the parasite adhesion rates to almost those detected in control insects. These results point out that ecdysone may be a factor responsible - directly or indirectly - by the modulation of rectum ultrastructural arrangement providing a superficial wax layer to the attachment followed by metacyclogenesis of T. cruzi in the rectum of its invertebrate hosts.


Assuntos
Doença de Chagas , Rhodnius , Trypanosoma cruzi , Animais , Doença de Chagas/tratamento farmacológico , Ecdisona/farmacologia , Ninfa , Reto/parasitologia , Reto/ultraestrutura , Rhodnius/parasitologia
14.
Nature ; 603(7899): 112-118, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35197627

RESUMO

The assembly of neural circuits is dependent on precise spatiotemporal expression of cell recognition molecules1-5. Factors controlling cell type specificity have been identified6-8, but how timing is determined remains unknown. Here we describe induction of a cascade of transcription factors by a steroid hormone (ecdysone) in all fly visual system neurons spanning target recognition and synaptogenesis. We demonstrate through single-cell sequencing that the ecdysone pathway regulates the expression of a common set of targets required for synaptic maturation and cell-type-specific targets enriched for cell-surface proteins regulating wiring specificity. Transcription factors in the cascade regulate the expression of the same wiring genes in complex ways, including activation in one cell type and repression in another. We show that disruption of the ecdysone pathway generates specific defects in dendritic and axonal processes and synaptic connectivity, with the order of transcription factor expression correlating with sequential steps in wiring. We also identify shared targets of a cell-type-specific transcription factor and the ecdysone pathway that regulate specificity. We propose that neurons integrate a global temporal transcriptional module with cell-type-specific transcription factors to generate different cell-type-specific patterns of cell recognition molecules regulating wiring.


Assuntos
Proteínas de Drosophila , Ecdisona , Animais , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Ecdisona/metabolismo , Regulação da Expressão Gênica , Sinapses/metabolismo , Fatores de Transcrição/metabolismo
15.
J Insect Physiol ; 138: 104368, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35134451

RESUMO

Locusts have been known as pests of agricultural crops for thousands of years. Recently (2018-2021) the world has faced the largest swarms of desert locusts, Schistocerca gregaria, in decades and food security in large parts of Africa and Asia was under extreme pressure. There is an urgent need for the development of highly specific bio-rational pesticides to combat these pests. However, to do so, fundamental research is needed to better understand the molecular mechanisms behind key physiological processes underpinning swarm formation, such as development and reproduction. The scope of this study is to investigate the possible role(s) of the ecdysteroid receptor in the reproductive physiology of male S. gregaria. Ecdysteroids and juvenile hormones are two important classes of insect hormones and are key regulators of post-embryonic development. Ecdysteroids are best known for their role in moulting and exert their function via a heterodimer consisting of the nuclear receptors ecdysone receptor (EcR) and retinoid-X receptor (RXR). To gain insight into the role of SgEcR and/or SgRXR in the male reproductive physiology of S. gregaria we performed RNAi-induced knockdown experiments. A knockdown of SgEcR, but not SgRXR, resulted in an increased relative weight of the male accessory glands (MAG). Furthermore, the knockdown of these genes, either in combination or separately, caused a significant delay in the onset of mating behavior. Nevertheless, the MAG appeared to mature normally and the fertility of mated males was not affected. The high transcript levels of SgEcR in the fat body, especially towards the end of sexual maturation in both males and females, represent a remarkable finding since as of yet the exact role of SgEcR in this tissue in S. gregaria is unknown. Finally, our data suggest that in some cases SgEcR and SgRXR might act independently of each other. This is supported by the fact that the spatiotemporal expression profiles of SgEcR and SgRXR do not always coincide and that knockdown of SgEcR, but not SgRXR, significantly affected the relative weight of the MAG.


Assuntos
Ecdisteroides , Gafanhotos , Animais , Ecdisona/metabolismo , Ecdisteroides/metabolismo , Feminino , Gafanhotos/fisiologia , Hormônios Juvenis/metabolismo , Masculino , Muda , Receptores de Esteroides
16.
Pestic Biochem Physiol ; 181: 105017, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35082040

RESUMO

Broflanilide is a novel insecticide with a unique mode of action on the insect GABA receptor and is registered worldwide for the control of agricultural pests. It shows high efficacy in controlling the fall armyworm (FAW) Spodoptera frugiperda, which is a destructive pest to various crops. FAW was exposed to sublethal concentrations of broflanilide to determine its impact on insect development. Sublethal doses (LD10 and LD30) caused failure of ecdysis, reduced body length of larvae, malformation of pupae, and vestigial wing formation in adults. Also, broflanilide at LD30 significantly reduced the amount of molting hormone (MH). After exposure to LD10 or LD30 broflanilide, expression of five Halloween genes, which participate in MH biosynthesis, were found to be altered. Specifically, the transcript levels of SfrCYP307A1 (Spook), SfrCYP314A1 (Shade) and SfrCYP315A1 (Shadow) in 3rd day larvae were significantly decreased as well as SfrCYP302A1 (Disembodied) and SfrCYP306A1 (Phantom) in 5th day pupae. In contrast, the transcript levels of SfrCYP302A1 in 3rd day larvae, SfrCYP307A1 and SfrCYP314A1 in 5th day pupae, and SfrCYP306A1, SfrCYP307A1 and SfrCYP315A1 in 0.5th day adults were significantly increased. Our results demonstrate that broflanilide caused the failure of ecdysis in FAW possibly by influencing the intake of cholesterol through inhibition of feeding and also via altering expression of genes important for MH biosynthesis.


Assuntos
Ecdisona , Muda , Animais , Benzamidas , Fluorcarbonetos , Larva , Spodoptera/genética
17.
PLoS Genet ; 18(1): e1009519, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35077443

RESUMO

The blood brain barrier (BBB) forms a stringent barrier that protects the brain from components in the circulation that could interfere with neuronal function. At the same time, the BBB enables selective transport of critical nutrients and other chemicals to the brain. Beyond these functions, another recently recognized function is even less characterized, specifically the role of the BBB in modulating behavior by affecting neuronal function in a sex-dependent manner. Notably, signaling in the adult Drosophila BBB is required for normal male courtship behavior. Courtship regulation also relies on male-specific molecules in the BBB. Our previous studies have demonstrated that adult feminization of these cells in males significantly lowered courtship. Here, we conducted microarray analysis of BBB cells isolated from males and females. Findings revealed that these cells contain male- and female-enriched transcripts, respectively. Among these transcripts, nuclear receptor Hr46/Hr3 was identified as a male-enriched BBB transcript. Hr46/Hr3 is best known for its essential roles in the ecdysone response during development and metamorphosis. In this study, we demonstrate that Hr46/Hr3 is specifically required in the BBB cells for courtship behavior in mature males. The protein is localized in the nuclei of sub-perineurial glial cells (SPG), indicating that it might act as a transcriptional regulator. These data provide a catalogue of sexually dimorphic BBB transcripts and demonstrate a physiological adult role for the nuclear receptor Hr46/Hr3 in the regulation of male courtship, a novel function that is independent of its developmental role.


Assuntos
Barreira Hematoencefálica/metabolismo , Corte , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Drosophila melanogaster/genética , Ecdisona/metabolismo , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Caracteres Sexuais , Comportamento Sexual Animal/fisiologia
18.
Proc Natl Acad Sci U S A ; 119(5)2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35086929

RESUMO

In Drosophila melanogaster, loss of regenerative capacity in wing imaginal discs coincides with an increase in systemic levels of the steroid hormone ecdysone, a key coordinator of their developmental progression. Regenerating discs release the relaxin hormone Dilp8 (Drosophila insulin-like peptide 8) to limit ecdysone synthesis and extend the regenerative period. Here, we describe how regenerating tissues produce a biphasic response to ecdysone levels: lower concentrations of ecdysone promote local and systemic regenerative signaling, whereas higher concentrations suppress regeneration through the expression of broad splice isoforms. Ecdysone also promotes the expression of wingless during both regeneration and normal development through a distinct regulatory pathway. This dual role for ecdysone explains how regeneration can still be completed successfully in dilp8- mutant larvae: higher ecdysone levels increase the regenerative activity of tissues, allowing regeneration to reach completion in a shorter time. From these observations, we propose that ecdysone hormone signaling functions to coordinate regeneration with developmental progression.


Assuntos
Ecdisona/metabolismo , Regeneração/fisiologia , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Expressão Gênica/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Hormônios Esteroides Gonadais/metabolismo , Discos Imaginais/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Larva/crescimento & desenvolvimento , Neurônios/metabolismo , Transdução de Sinais/fisiologia , Fatores de Transcrição/metabolismo , Asas de Animais/metabolismo , Proteína Wnt1/metabolismo
19.
Dis Model Mech ; 15(1)2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34842272

RESUMO

Development involves tightly paced, reproducible sequences of events, yet it must adjust to conditions external to it, such as resource availability and organismal damage. A major mediator of damage-induced immune responses in vertebrates and insects is JAK/STAT signaling. At the same time, JAK/STAT activation by the Drosophila Upd cytokines is pleiotropically involved in normal development of multiple organs. Whether inflammatory and developmental JAK/STAT roles intersect is unknown. Here, we show that JAK/STAT is active during development of the prothoracic gland (PG), which controls metamorphosis onset through ecdysone production. Reducing JAK/STAT signaling decreased PG size and advanced metamorphosis. Conversely, JAK/STAT hyperactivation by overexpression of pathway components or SUMOylation loss caused PG hypertrophy and metamorphosis delay. Tissue damage and tumors, known to secrete Upd cytokines, also activated JAK/STAT in the PG and delayed metamorphosis, at least in part by inducing expression of the JAK/STAT target Apontic. JAK/STAT damage signaling, therefore, regulates metamorphosis onset by co-opting its developmental role in the PG. Our findings in Drosophila provide insights on how systemic effects of damage and cancer can interfere with hormonally controlled development and developmental transitions.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Ecdisona/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Transdução de Sinais/fisiologia
20.
Insect Sci ; 29(1): 100-110, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34018323

RESUMO

Periodic post-embryonic changes in insects, including growth, development and metamorphosis, are strictly controlled by many compounds, including steroid hormones. The biosynthesis and clearance of 20-hydroxyecdysone (20E), the major active form of the insect steroid hormone ecdysone, result in titer fluctuations that help control insect development. The inactivation of 20E in the silkworm Bombyx mori is highly tissue-specific, with CYP18A1 and ecdysone oxidase controlling 20E inactivation specifically in the mid-silk gland and midgut, respectively. Here, we characterized silkworm 3-dehydroecdysone 3α reductase (Bm3DE3α) and 3-dehydroecdysone 3ß reductase (Bm3DE3ß), two enzymes involved predominantly in the C-3-mediated catalysis of 20E in fat bodies. The ubiquitous and silk gland-specific overexpression of Bm3DE3α decreased the 20E titer, resulting in larval lethality and larval-pupal transition failure, respectively. In contrast, the ubiquitous and mid-silk gland-specific overexpression of Bm3DE3ß increased the 20E titer, resulting in larval growth delays and lethality at the mid-fifth larval stage, respectively. Thus, Bm3DE3α and Bm3DE3ß mediate fat body-specific steroid hormone metabolism in B. mori, indicating that highly diversified 20E metabolism-related mechanisms exist in different insect species.


Assuntos
Bombyx , Animais , Ecdisona , Ecdisterona , Corpo Adiposo , Proteínas de Insetos/genética , Larva , Oxirredutases
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