Coordination among multiple receptor tyrosine kinase signals controls Drosophila developmental timing and body size

Soul is a master control gene governing the development of the Drosophila prothoracic gland

The prothoracic gland (PG) is a major insect endocrine organ. It is the principal source of insect steroid hormones, and critical for key developmental events such as the molts, the establishment of critical weight (CW), pupation, and sexual maturation. However, little is known about the developmental processes that regulate PG morphology. In this study, we identified soul, which encodes a PG-specific basic helix-loop-helix (bHLH) transcription factor. We demonstrate that Tap, also a bHLH protein, dimerizes with Soul. Both are expressed in the developing PG. Interfering with either soul or tap function caused strikingly similar phenotypes, resulting in small and fragmented PGs, the abolishment of steroid hormone-producing gene expression, larval arrest, and a failure to undergo metamorphosis. Furthermore, both soul and tap showed expression peaks just prior to the CW checkpoint. Disrupting soul- or tap-function before, but not after, the CW checkpoint caused larval arrest, and perturbed highly similar gene cohorts, which were enriched for regulators and components of the steroid hormone biosynthesis pathway. Intriguingly, a chitin-based cuticle gene, Cpr49Ah, and a POU domain transcription factor gene, pdm3, are direct target genes of the Soul/Tap complex, and disruption of either phenocopied key aspects of soul/tap loss-of-function phenotypes. Taken together, our findings demonstrate that the Soul/Tap heterodimer resides at the top of a complex gene hierarchy that drives PG development, CW establishment, and steroid hormone production.

Developmental analysis of Spalt function in the Drosophila prothoracic gland

The Spalt transcriptional regulators participate in a variety of cell fate specification processes during development, regulating transcription through interactions with DNA AT-rich regions. Spalt proteins also bind to heterochromatic regions, and some of their effects require interactions with the NuRD chromatin remodeling and deacetylase complex. Most of the biological roles of Spalt proteins have been characterized in diploid cells engaged in cell proliferation. Here, we address the function of Drosophila Spalt genes in the development of a larval tissue formed by polyploid cells, the prothoracic gland, the cells of which undergo several rounds of DNA replication without mitosis during larval development. We show that prothoracic glands depleted of Spalt expression display severe changes in the size of the nucleolus, the morphology of the nuclear envelope and the disposition of the chromatin within the nucleus, leading to a failure in the synthesis of ecdysone. We propose that loss of ecdysone production in the prothoracic gland of Spalt mutants is primarily caused by defects in nuclear pore complex function that occur as a consequence of faulty interactions between heterochromatic regions and the nuclear envelope.

The moulting arthropod: a complete genetic toolkit review

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.

Integrated ML-Based Strategy Identifies Drug Repurposing for Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) affects an estimated global population of around 3 million individuals. IPF is a medical condition with an unknown cause characterized by the formation of scar tissue in the lungs, leading to progressive respiratory disease. Currently, there are only two FDA-approved small molecule drugs specifically for the treatment of IPF and this has created a demand for the rapid development of drugs for IPF treatment. Moreover, denovo drug development is time and cost-intensive with less than a 10% success rate. Drug repurposing currently is the most feasible option for rapidly making the drugs to market for a rare and sporadic disease. Normally, the repurposing of drugs begins with a screening of FDA-approved drugs using computational tools, which results in a low hit rate. Here, an integrated machine learning-based drug repurposing strategy is developed to significantly reduce the false positive outcomes by introducing the predock machine-learning-based predictions followed by literature and GSEA-assisted validation and drug pathway prediction. The developed strategy is deployed to 1480 FDA-approved drugs and to drugs currently in a clinical trial for IPF to screen them against "TGFB1", "TGFB2", "PDGFR-a", "SMAD-2/3", "FGF-2", and more proteins resulting in 247 total and 27 potentially repurposable drugs. The literature and GSEA validation suggested that 72 of 247 (29.14%) drugs have been tried for IPF, 13 of 247 (5.2%) drugs have already been used for lung fibrosis, and 20 of 247 (8%) drugs have been tested for other fibrotic conditions such as cystic fibrosis and renal fibrosis. Pathway prediction of the remaining 142 drugs was carried out resulting in 118 distinct pathways. Furthermore, the analysis revealed that 29 of 118 pathways were directly or indirectly involved in IPF and 11 of 29 pathways were directly involved. Moreover, 15 potential drug combinations are suggested for showing a strong synergistic effect in IPF. The drug repurposing strategy reported here will be useful for rapidly developing drugs for treating IPF and other related conditions.

The Alk receptor tyrosine kinase regulates Sparkly, a novel activity regulating neuropeptide precursor in the Drosophila central nervous system

Numerous roles for the Alk receptor tyrosine kinase have been described in Drosophila, including functions in the central nervous system (CNS), however the molecular details are poorly understood. To gain mechanistic insight, we employed Targeted DamID (TaDa) transcriptional profiling to identify targets of Alk signaling in the larval CNS. TaDa was employed in larval CNS tissues, while genetically manipulating Alk signaling output. The resulting TaDa data were analyzed together with larval CNS scRNA-seq datasets performed under similar conditions, identifying a role for Alk in the transcriptional regulation of neuroendocrine gene expression. Further integration with bulk and scRNA-seq datasets from larval brains in which Alk signaling was manipulated identified a previously uncharacterized Drosophila neuropeptide precursor encoded by CG4577 as an Alk signaling transcriptional target. CG4577, which we named Sparkly (Spar), is expressed in a subset of Alk-positive neuroendocrine cells in the developing larval CNS, including circadian clock neurons. In agreement with our TaDa analysis, overexpression of the Drosophila Alk ligand Jeb resulted in increased levels of Spar protein in the larval CNS. We show that Spar protein is expressed in circadian (clock) neurons, and flies lacking Spar exhibit defects in sleep and circadian activity control. In summary, we report a novel activity regulating neuropeptide precursor gene that is regulated by Alk signaling in the Drosophila CNS.

Hypoxia delays steroid-induced developmental maturation in Drosophila by suppressing EGF signaling

Animals often grow and develop in unpredictable environments where factors like food availability, temperature, and oxygen levels can fluctuate dramatically. To ensure proper sexual maturation into adulthood, juvenile animals need to adapt their growth and developmental rates to these fluctuating environmental conditions. Failure to do so can result in impaired maturation and incorrect body size. Here we describe a mechanism by which Drosophila larvae adapt their development in low oxygen (hypoxia). During normal development, larvae grow and increase in mass until they reach critical weight (CW), after which point a neuroendocrine circuit triggers the production of the steroid hormone ecdysone from the prothoracic gland (PG), which promotes maturation to the pupal stage. However, when raised in hypoxia (5% oxygen), larvae slow their growth and delay their maturation to the pupal stage. We find that, although hypoxia delays the attainment of CW, the maturation delay occurs mainly because of hypoxia acting late in development to suppress ecdysone production. This suppression operates through a distinct mechanism from nutrient deprivation, occurs independently of HIF-1 alpha and does not involve dilp8 or modulation of Ptth, the main neuropeptide that initiates ecdysone production in the PG. Instead, we find that hypoxia lowers the expression of the EGF ligand, spitz, and that the delay in maturation occurs due to reduced EGFR/ERK signaling in the PG. Our study sheds light on how animals can adjust their development rate in response to changing oxygen levels in their environment. Given that hypoxia is a feature of both normal physiology and many diseases, our findings have important implications for understanding how low oxygen levels may impact animal development in both normal and pathological situations.

Timed receptor tyrosine kinase signaling couples the central and a peripheral circadian clock in Drosophila

Circadian clocks impose daily periodicities to behavior, physiology, and metabolism. This control is mediated by a central clock and by peripheral clocks, which are synchronized to provide the organism with a unified time through mechanisms that are not fully understood. Here, we characterized in Drosophila the cellular and molecular mechanisms involved in coupling the central clock and the peripheral clock located in the prothoracic gland (PG), which together control the circadian rhythm of emergence of adult flies. The time signal from central clock neurons is transmitted via small neuropeptide F (sNPF) to neurons that produce the neuropeptide Prothoracicotropic Hormone (PTTH), which is then translated into daily oscillations of Ca2+ concentration and PTTH levels. PTTH signaling is required at the end of metamorphosis and transmits time information to the PG through changes in the expression of the PTTH receptor tyrosine kinase (RTK), TORSO, and of ERK phosphorylation, a key component of PTTH transduction. In addition to PTTH, we demonstrate that signaling mediated by other RTKs contributes to the rhythmicity of emergence. Interestingly, the ligand to one of these receptors (Pvf2) plays an autocrine role in the PG, which may explain why both central brain and PG clocks are required for the circadian gating of emergence. Our findings show that the coupling between the central and the PG clock is unexpectedly complex and involves several RTKs that act in concert and could serve as a paradigm to understand how circadian clocks are coordinated.

KDM5-mediated activation of genes required for mitochondrial biology is necessary for viability in Drosophila

Histone-modifying proteins play important roles in the precise regulation of the transcriptional programs that coordinate development. KDM5 family proteins interact with chromatin through demethylation of H3K4me3 as well as demethylase-independent mechanisms that remain less understood. To gain fundamental insights into the transcriptional activities of KDM5 proteins, we examined the essential roles of the single Drosophila Kdm5 ortholog during development. KDM5 performs crucial functions in the larval neuroendocrine prothoracic gland, providing a model to study its role in regulating key gene expression programs. Integrating genome binding and transcriptomic data, we identify that KDM5 regulates the expression of genes required for the function and maintenance of mitochondria, and we find that loss of KDM5 causes morphological changes to mitochondria. This is key to the developmental functions of KDM5, as expression of the mitochondrial biogenesis transcription factor Ets97D, homolog of GABPα, is able to suppress the altered mitochondrial morphology as well as the lethality of Kdm5 null animals. Together, these data establish KDM5-mediated cellular functions that are important for normal development and could contribute to KDM5-linked disorders when dysregulated.

The macrophage genetic cassette inr/dtor/pvf2 is a nutritional status checkpoint for developmental timing

A small number of signaling molecules, used reiteratively, control differentiation programs, but the mechanisms that adapt developmental timing to environmental cues are less understood. We report here that a macrophage inr/dtor/pvf2 genetic cassette is a developmental timing checkpoint in Drosophila, which either licenses or delays biosynthesis of the steroid hormone in the endocrine gland and metamorphosis according to the larval nutritional status. Insulin receptor/dTor signaling in macrophages is required and sufficient for production of the PDGF/VEGF family growth factor Pvf2, which turns on transcription of the sterol biosynthesis Halloween genes in the prothoracic gland via its receptor Pvr. In response to a starvation event or genetic manipulation, low Pvf2 signal delays steroid biosynthesis until it becomes Pvr-independent, thereby prolonging larval growth before pupariation. The significance of this developmental timing checkpoint for host fitness is illustrated by the observation that it regulates the size of the pupae and adult flies.

Expression of tyrosine phosphatases in relation to PTTH-stimulated ecdysteroidogenesis in prothoracic glands of the silkworm, Bombyx mori

Protein tyrosine phosphorylation is a reversible, dynamic process regulated by the activities of tyrosine kinases and tyrosine phosphatases. Although the involvement of tyrosine kinases in the prothoracicotropic hormone (PTTH)-stimulated ecdysteroidogenesis in insect prothoracic glands (PGs) has been documented, few studies have been conducted on the involvement of protein tyrosine phosphatases (PTPs) in PTTH-stimulated ecdysteroidogenesis. In the present study, we investigated the correlation between PTPs and PTTH-stimulated ecdysteroidogenesis in Bombyx mori PGs. Our results showed that the basal PTP enzymatic activities exhibited development-specific changes during the last larval instar and pupation stage, with high activities being detected during the later stages of the last larval instar. PTP enzymatic activity was stimulated by PTTH treatment both in vitro and in vivo. Pretreatment with phenylarsine oxide (PAO) and benzylphosphonic acid (BPA), two chemical inhibitors of tyrosine phosphatase, reduced PTTH-stimulated enzymatic activity. Determination of ecdysteroid secretion showed that treatment with PAO and BPA did not affect basal ecdysteroid secretion, but greatly inhibited PTTH-stimulated ecdysteroid secretion, indicating that PTTH-stimulated PTP activity is indeed involved in ecdysteroid secretion. PTTH-stimulated phosphorylation of the extracellular signal-regulated kinase (ERK) and 4E-binding protein (4E-BP) was partially inhibited by pretreatment with either PAO or BPA, indicating the potential link between PTPs and phosphorylation of ERK and 4E-BP. In addition, we also found that in vitro treatment with 20-hydroxyecdysone did not affect PTP enzymatic activity. We further investigated the expressions of two important PTPs (PTP 1B (PTP1B) and the phosphatase and tension homologue (PTEN)) in Bombyx PGs. Our immunoblotting analysis showed that B. mori PGs contained the proteins of PTP1B and PTEN, with PTP1B protein undergoing development-specific changes. Protein levels of PTP1B and PTEN were not affected by PTTH treatment. The gene expression levels of PTP1B and PTEN showed development-specific changes. From these results, we suggest that PTTH-regulated PTP signaling may crosstalk with ERK and target of rapamycin (TOR) signaling pathways and is a necessary component for stimulation of ecdysteroid secretion.

Endoreplication in the Drosophila melanogaster prothoracic gland is dispensable for the critical weight checkpoint

Critical weight (CW) attainment is a key life event in the development of holometabolous insects including Drosophila melanogaster. It indicates that sufficient growth has occurred to initiate the juvenile-to-adult transition. The prothoracic gland (PG), the major insect larval endocrine organ, is a polyploid tissue that plays a key role in the determination of CW via release of the steroid hormone ecdysone. Here we show that when the cells of the PG fail to make the mitotic-to-endocycle switch, but instead remain mitotic, the result is more but smaller cells. Nevertheless, they reach the same CW and produce healthy adults after only a moderate developmental delay. We propose that the CW checkpoint can be reached by either an endocycling or mitotic PG and may simply reflect the attainment of sufficient ecdysone biosynthetic capacity to initiate metamorphosis.

Mammalian puberty: a fly perspective

Mammalian puberty and Drosophila metamorphosis, despite their evolutionary distance, exhibit similar design principles and conservation of molecular components. In this Viewpoint, we review recent advances in this area and the similarities between both processes in terms of the signaling pathways and neuroendocrine circuits involved. We argue that the detection and uptake of peripheral fat by Drosophila prothoracic endocrine cells induces endomembrane remodeling and ribosomal maturation, leading to the acquisition of high biosynthetic and secretory capacity. The absence of this fat-neuroendocrine interorgan communication leads to giant, obese, non-pupating larvae. Importantly, human leptin is capable of signaling the pupariation process in Drosophila, and its expression prevents obesity and triggers maturation in mutants that do not pupate. This implies that insect metamorphosis can be used to address issues related to the biology of leptin and puberty.

Egfr signaling promotes juvenile hormone biosynthesis in the German cockroach

BACKGROUND

In insects, an interplay between the activities of distinct hormones, such as juvenile hormone (JH) and 20-hydroxyecdysone (20E), regulates the progression through numerous life history hallmarks. As a crucial endocrine factor, JH is mainly synthesized in the corpora allata (CA) to regulate multiple physiological and developmental processes, including molting, metamorphosis, and reproduction. During the last century, significant progress has been achieved in elucidating the JH signal transduction pathway, while less progress has been made in dissecting the regulatory mechanism of JH biosynthesis. Previous work has shown that receptor tyrosine kinase (RTK) signaling regulates hormone biosynthesis in both insects and mammals. Here, we performed a systematic RNA interference (RNAi) screening to identify RTKs involved in regulating JH biosynthesis in the CA of adult Blattella germanica females.

RESULTS

We found that the epidermal growth factor receptor (Egfr) is required for promoting JH biosynthesis in the CA of adult females. The Egf ligands Vein and Spitz activate Egfr, followed by Ras/Raf/ERK signaling, and finally activation of the downstream transcription factor Pointed (Pnt). Importantly, Pnt induces the transcriptional expression of two key enzyme-encoding genes in the JH biosynthesis pathway: juvenile hormone acid methyltransferase (JHAMT) and methyl farnesoate epoxidase (CYP15A1). Dual-luciferase reporter assay shows that Pnt is able to activate a promoter region of Jhamt. In addition, electrophoretic mobility shift assay confirms that Pnt directly binds to the - 941~ - 886 nt region of the Jhamt promoter.

CONCLUSIONS

This study reveals the detailed molecular mechanism of Egfr signaling in promoting JH biosynthesis in the German cockroach, shedding light on the intricate regulation of JH biosynthesis during insect development.

Interorgan communication through peripherally derived peptide hormones in Drosophila

In multicellular organisms, endocrine factors such as hormones and cytokines regulate development and homoeostasis through communication between different organs. For understanding such interorgan communications through endocrine factors, the fruit fly Drosophila melanogaster serves as an excellent model system due to conservation of essential endocrine systems between flies and mammals and availability of powerful genetic tools. In Drosophila and other insects, functions of neuropeptides or peptide hormones from the central nervous system have been extensively studied. However, a series of recent studies conducted in Drosophila revealed that peptide hormones derived from peripheral tissues also play critical roles in regulating multiple biological processes, including growth, metabolism, reproduction, and behaviour. Here, we summarise recent advances in understanding target organs/tissues and functions of peripherally derived peptide hormones in Drosophila and describe how these hormones contribute to various biological events through interorgan communications.

A local insulin reservoir in Drosophila alpha cell homologs ensures developmental progression under nutrient shortage

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.

Transcriptional Regulators of Ecdysteroid Biosynthetic Enzymes and Their Roles in Insect Development

Steroid hormones are responsible for coordinating many aspects of biological processes in most multicellular organisms, including insects. Ecdysteroid, the principal insect steroid hormone, is biosynthesized from dietary cholesterol or plant sterols. In the last 20 years, a number of ecdysteroidogenic enzymes, including Noppera-bo, Neverland, Shroud, Spook/Spookier, Cyp6t3, Phantom, Disembodied, Shadow, and Shade, have been identified and characterized in molecular genetic studies using the fruit fly Drosophila melanogaster. These enzymes are encoded by genes collectively called the Halloween genes. The transcriptional regulatory network, governed by multiple regulators of transcription, chromatin remodeling, and endoreplication, has been shown to be essential for the spatiotemporal expression control of Halloween genes in D. melanogaster. In this review, we summarize the latest information on transcriptional regulators that are crucial for controlling the expression of ecdysteroid biosynthetic enzymes and their roles in insect development.

Endocrine Regulation of Lifespan in Insect Diapause

Diapause is a physiological adaptation to conditions that are unfavorable for growth or reproduction. During diapause, animals become long-lived, stress-resistant, developmentally static, and non-reproductive, in the case of diapausing adults. Diapause has been observed at all developmental stages in both vertebrates and invertebrates. In adults, diapause traits weaken into adaptations such as hibernation, estivation, dormancy, or torpor, which represent evolutionarily diverse versions of the traditional diapause traits. These traits are regulated through modifications of the endocrine program guiding development. In insects, this typically includes changes in molting hormones, as well as metabolic signals that limit growth while skewing the organism's energetic demands toward conservation. While much work has been done to characterize these modifications, the interactions between hormones and their downstream consequences are incompletely understood. The current state of diapause endocrinology is reviewed here to highlight the relevance of diapause beyond its use as a model to study seasonality and development. Specifically, insect diapause is an emerging model to study mechanisms that determine lifespan. The induction of diapause represents a dramatic change in the normal progression of age. Hormones such as juvenile hormone, 20-hydroxyecdysone, and prothoracicotropic hormone are well-known to modulate this plasticity. The induction of diapause-and by extension, the cessation of normal aging-is coordinated by interactions between these pathways. However, research directly connecting diapause endocrinology to the biology of aging is lacking. This review explores connections between diapause and aging through the perspective of endocrine signaling. The current state of research in both fields suggests appreciable overlap that will greatly contribute to our understanding of diapause and lifespan determination.

Intrinsic and damage-induced JAK/STAT signaling regulate developmental timing by the Drosophila prothoracic gland

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.

Summary: Damage signaling from tumors mediated by JAK/STAT-activating Upd cytokines delays the Drosophila larva–pupa transition through co-option of a JAK/STAT developmental role in the prothoracic gland.