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Do-Hwan Lim, Seungjae Lee, Jee Yun Han, Min-Seok Choi, Jae-Sang Hong, Youngmo Seong, Young-Soo Kwon, Young Sik Lee
The steroid hormone ecdysone has a central role in the developmental transitions of insects through its control of responsive protein-coding and microRNA (miRNA) gene expression. However, the complete regulatory network controlling the expression of these genes remains to be elucidated. In this study, we performed cross-linking immunoprecipitation coupled with deep sequencing of endogenous Argonaute 1 (Ago1) protein, the core effector of the miRNA pathway, in Drosophila S2 cells. We found that regulatory interactions between miRNAs and their cognate targets were substantially altered by Ago1 in response to ecdysone signaling...
March 15, 2018: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Xueping Hu, Bin Yin, Kaat Cappelle, Luc Swevers, Guy Smagghe, Xinling Yang, Li Zhang
Insect growth is regulated by the steroid hormone 20-hydroxyecdysone (20E), which works via the ecdysone receptor (EcR). To identify biologically active and novel ecdysone agonists/antagonists, ligand/structure-based virtual screening combined with pharmacophore modeling and molecular docking was performed to identify novel nonsteroidal lead compounds. Nine molecules were screened and selected for an in vitro cell-based reporter bioassay. The results showed that VS-006 and VS-009 exhibited antagonistic activity in S2 cells, whereas only VS-006 exhibited antagonistic activity in Bm5 cells...
March 2, 2018: Journal of Molecular Graphics & Modelling
Dujuan Dong, Yang Zhang, Vlastimil Smykal, Lin Ling, Alexander S Raikhel
The Aedes aegypti mosquito is the principal vector for many dangerous human viral diseases. Carbohydrate metabolism (CM) is essential for supplying the energy necessary for host seeking, blood digestion and rapid egg development of this vector insect. The steroid hormone 20-hydroxyecdysone (20E) and the ecdysone receptor (EcR) are important regulators of CM, coordinating it with female reproductive events. We report here that the NR4A nuclear receptor AHR38 plays a critical role in mediating these actions of 20E and EcR...
March 8, 2018: Insect Biochemistry and Molecular Biology
Birgitte Nilsson, Benni Winding Hansen
Like 41 other calanoid copepods, Acartia tonsa, are capable of inducing embryonic quiescence when experiencing unfavorable environmental conditions. The ecdysone-signaling cascade is known to have a key function in developmental processes like embryogenesis and molting of arthropods, including copepods. We examined the role of ecdysteroid-phosphate phosphatase (EPPase), ecdysone receptor (EcR), ß fushi tarazu transcription factor 1 (ßFTZ-F1), and the ecdysteroid-regulated early gene E74 (E74), which represent different levels of the ecdysone-signaling cascade in our calanoid model organism...
2018: PloS One
D Gouveia, F Bonneton, C Almunia, J Armengaud, H Quéau, D Degli-Esposti, O Geffard, A Chaumot
Taking advantage of a large transcriptomic dataset recently obtained in the sentinel crustacean amphipod Gammarus fossarum, we developed an approach based on sequence similarity and phylogenetic reconstruction to identify key players involved in the endocrine regulation of G. fossarum. Our work identified three genes of interest: the nuclear receptors RXR and E75, and the regulator broad-complex (BR). Their involvement in the regulation of molting and reproduction, along with their sensitivity to chemical contamination were experimentally assessed by studying gene expression during the female reproductive cycle, and after laboratory exposure to model endocrine disrupting compounds (EDCs): pyriproxyfen, tebufenozide and piperonyl butoxide...
February 28, 2018: Scientific Reports
Laura Palanker Musselman, Jill L Fink, Ezekiel J Maier, Jared A Gatto, Michael R Brent, Thomas J Baranski
Insulin resistance is associated with obesity, cardiovascular disease, non-alcoholic fatty liver disease, and type 2 diabetes. These complications are exacerbated by a high-calorie diet, which we used to model type 2 diabetes in Drosophila melanogaster Our studies focused on the fat body, an adipose- and liver-like tissue that stores fat and maintains circulating glucose. A gene regulatory network was constructed to predict potential regulators of insulin signaling in this tissue. Genomic characterization of fat bodies suggested a central role for the transcription factor Seven-up (Svp)...
February 27, 2018: Genetics
Kai Lu, Xia Chen, Yue Li, Wenru Li, Qiang Zhou
Insect lipophorin receptor (LpR) belongs to the low-density lipoprotein receptor (LDLR) superfamily and plays an essential role in fecundity by mediating the incorporation of lipophorin into developing oocytes. Here we report the identification and characterization of a full-length cDNA encoding a putative LpR from the brown planthopper, Nilaparvata lugens. The deduced amino acid sequence of NlLpR possesses the conserved structural motifs of LDLR family members, and displays a high degree of similarity with sequences from other insect LpRs...
February 21, 2018: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
H Frederik Nijhout, Emily Laub, Laura W Grunert
The wing imaginal disks of Lepidoptera can be grown in tissue culture, but require both insulin and ecdysone to grow normally. Here we investigate the contributions the two hormones make to growth. Ecdysone is required to maintain mitoses, whereas in the presence of insulin alone mitoses stop. Both ecdysone and insulin stimulate protein synthesis, but only ecdysone stimulates DNA synthesis. Insulin stimulates primarily cytoplasmic growth and an increase in cell size, whereas ecdysone, by virtue of its stimulation of DNA synthesis and mitosis, stimulates growth by an increase in cell number...
February 21, 2018: Development
MaryJane Shimell, Xueyang Pan, Francisco A Martin, Arpan C Ghosh, Pierre Leopold, Michael B O'Connor, Nuria M Romero
Adult size and fitness are controlled by a combination of genetics and environmental cues. In Drosophila , growth is confined to the larval phase and final body size is impacted by the duration of this phase, which is under neuroendocrine control. The neuropeptide prothoracicotropic hormone (PTTH) has been proposed to play a central role in controlling the length of the larval phase through regulation of ecdysone production, a steroid hormone that initiates larval molting and metamorphosis. Here, we test this issue by examining the consequences of null mutations in the ptth gene on Drosophila development...
February 21, 2018: Development
Óscar Herrero, Mónica Aquilino, Paloma Sánchez-Argüello, Rosario Planelló
Bisphenol S (BPS) is an industrial alternative to the endocrine disruptor bisphenol A (BPA), and can be found in many products labeled "BPA-free". Its use has grown in recent years, and presently it is considered a ubiquitous emerging pollutant. To date there is a lack of information on the effects of BPS on invertebrates, although they represent more than 95% of known species in the animal kingdom and are crucial for the structure and proper function of ecosystems. In this study, real-time RT-PCR was used to determine the early detrimental effects of BPS on the transcriptional rate of genes in the model species Chironomus riparius, specifically those related to the ecdysone pathway (EcR, ERR, E74, Vtg, cyp18a1) crucial for insect development and metamorphosis, stress and biotransformation mechanisms (hsp70, hsp40, cyp4g, GPx, GSTd3) that regulate adaptive responses and determine survival, and ribosome biogenesis (its2, rpL4, rpL13) which is essential for protein synthesis and homeostasis...
2018: PloS One
Binglong Zhang, Kosei Sato, Daisuke Yamamoto
Some mAL neurons in the male brain form the ipsilateral neurite (ILN[+]) in a manner dependent on FruBM, a male-specific transcription factor. FruBM represses robo1 transcription, allowing the ILN to form. We found that the proportion of ILN[+]-mALs in all observed single cell clones dropped from ∼90% to ∼30% by changing the heat-shock timing for clone induction from 4-5 days after egg laying (AEL) to 6-7 days AEL, suggesting that the ILN[+]-mALs are produced predominantly by young neuroblasts. Upon EcR-A knockdown, ILN[+]-mALs were produced at a high rate (∼60%), even when heat shocked at 6-7 days AEL, yet EcR-B1 knockdown reduced the proportion of ILN[+]-mALs to ∼30%...
February 20, 2018: Biology Open
Carmen Scieuzo, Marisa Nardiello, Rosanna Salvia, Marco Pezzi, Milvia Chicca, Marilena Leis, Sabino A Bufo, S Bradleigh Vinson, Asha Rao, Heiko Vogel, Patrizia Falabella
Post-embryonic development and molting in insects are regulated by endocrine changes, including prothoracicotropic hormone (PTTH)-stimulated ecdysone secretion by the prothoracic glands (PGs). In Lepidoptera, two pathways are potentially involved in PTTH-stimulated ecdysteroidogenesis, mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase/protein kinase B/target of rapamycin (PI3K/Akt/TOR). We investigated the potential roles of both these pathways in Heliothis virescens ecdysteroidogenesis...
February 15, 2018: Journal of Insect Physiology
Marina Yu Mazina, Elena V Kovalenko, Polina K Derevyanko, Julia V Nikolenko, Aleksey N Krasnov, Nadezhda E Vorobyeva
Transcriptional activation is often represented as a "one-step process" that involves the simultaneous recruitment of co-activator proteins, leading to a change in gene status. Using Drosophila developmental ecdysone-dependent genes as a model, we demonstrated that activation of transcription is instead a continuous process that consists of a number of steps at which different phases of transcription (initiation or elongation) are stimulated. Thorough evaluation of the behaviour of multiple transcriptional complexes during the early activation process has shown that the pathways by which activation proceeds for different genes may vary considerably, even in response to the same induction signal...
February 5, 2018: Biochimica et Biophysica Acta
Fumihiko Igarashi, Mari H Ogihara, Masatoshi Iga, Hiroshi Kataoka
Dietary sterols including cholesterol and phytosterols are essential substrates for insect steroid hormone (ecdysteroid) synthesis in the prothoracic glands (PGs). In a silkworm Bombyx mori, one of the model species of insects, the steroidogenesis has been well demonstrated that cholesterol biotransformation into ecdysone in the PG cells. Because insects lack the ability to synthesize cellular sterol de novo, lipoprotein, lipophorin (Lp), has been thought to be the major cholesterol supply source; however, details of cholesterol behavior from Lp to the PG cells has not been analyzed till date...
January 31, 2018: Steroids
Liv Sandlund, Heidi Kongshaug, Tor Einar Horsberg, Rune Male, Frank Nilsen, Sussie Dalvin
The salmon louse is a marine ectoparasitic copepod on salmonid fishes. Its lifecycle consists of eight developmental stages, each separated by a molt. In crustaceans and insects, molting and reproduction is controlled by circulating steroid hormones such as 20-hydroxyecdysone. Steroid hormones are synthesized from cholesterol through catalytic reactions involving a 7,8-dehydrogenase Neverland and several cytochrome P450 genes collectively called the Halloween genes. In this study, we have isolated and identified orthologs of neverland, disembodied and shade in the salmon louse (Lepeophtheirus salmonis) genome...
2018: PloS One
Jinlin Jiang, Zhengjun Shan, Xiaorong Wang, Yuxuan Zhu, Junying Zhou
The nonsteroidal ecdysone mimic 1,2-dibenzoyl-1-tert-butylhydrazine (RH-5849), a novel insect growth regulator, is mainly registered for use in rice fields. So far, its toxicity and ecological risks towards aquatic cladoceran invertebrates remain unclear. In this study, RH-5849 was evaluated for its acute and 21-day chronic toxicity towards Daphnia magna. The viability, morphology, growth, and reproduction of D. magna were observed to establish a concentration-toxicity relationship associated with the RH-5849 exposure...
February 2, 2018: Environmental Science and Pollution Research International
Joshua B Benoit, Veronika Michalkova, Elise M Didion, Yanyu Xiao, Aaron A Baumann, Geoffrey M Attardo, Serap Aksoy
Tsetse flies are important vectors of human and animal trypanosomiasis. Ability to reduce tsetse populations is an effective means of disease control. Lactation is an essential component of tsetse's viviparous reproductive physiology and requires a dramatic increase in the expression and synthesis of milk proteins by the milk gland organ in order to nurture larval growth. In between each gonotrophic cycle, tsetse ceases milk production and milk gland tubules undergo a nearly two-fold reduction in width (involution)...
January 31, 2018: PLoS Neglected Tropical Diseases
Matthew R Meiselman, Timothy G Kingan, Michael E Adams
BACKGROUND: Environmental stressors induce changes in endocrine state, leading to energy re-allocation from reproduction to survival. Female Drosophila melanogaster respond to thermal and nutrient stressors by arresting egg production through elevation of the steroid hormone ecdysone. However, the mechanisms through which this reproductive arrest occurs are not well understood. RESULTS: Here we report that stress-induced elevation of ecdysone is accompanied by decreased levels of ecdysis triggering hormone (ETH)...
January 30, 2018: BMC Biology
Caroline Dillard, Karine Narbonne-Reveau, Sophie Foppolo, Elodie Lanet, Cédric Maurange
Whether common principles regulate the self-renewing potential of neural stem cells (NSCs) throughout the developing central nervous system is still unclear. In the Drosophila ventral nerve cord and central brain, asymmetrically dividing NSCs, called neuroblasts (NBs), progress through a series of sequentially expressed transcription factors that limits self-renewal by silencing a genetic module involving the transcription factor Chinmo. Here, we find that Chinmo also promotes neuroepithelium growth in the optic lobe during early larval stages by boosting symmetric self-renewing divisions while preventing differentiation...
December 22, 2017: Development
Amanda Glaser-Schmitt, John Parsch
Gene expression variation is a major contributor to phenotypic diversity within species and is thought to play an important role in adaptation. However, examples of adaptive regulatory polymorphism are rare, especially those that have been characterized at both the molecular genetic level and the organismal level. In this study, we perform a functional analysis of the Drosophila melanogaster CG9509 enhancer, a cis-regulatory element that shows evidence of adaptive evolution in populations outside the species' ancestral range in sub-Saharan Africa...
January 11, 2018: PLoS Biology
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