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Ecdysone - Wikipedia, the free encyclopedia Ecdysone is a prohormone of the major insect oulting hormone 20-hydroxyecdysone. Insect moulting hormones (ecdysone and its homologues) are generally called ecdysteroids. Ecdysteroids act as moulting hormones of arthropods but also occur in other invertebrates where they can play different role. en.wikipedia.org /wiki/Ecdysone   (128 words)

Developmental Biology Online: Drosophila Metamorphosis The ecdysone is released by the ring gland (which is a structure having regions similar to both the corpus allatum and prothoracic gland). A-ecdysone is synthesized in the prothoracic gland, which resides in the tissue of the ring gland, located anterior to the larval brain. A-ecdysone is converted in the fat body, and other target organs, to 20-hydroxyecdysone (with an additional hydroxyl group at position 20), 20,26-dihydroxymakisterone, 3-dehydroecdysteroids, makisterone A, and several other metabolites (Heftmann and Mosettig, 1970; Ridifford, 1993; Sliter and Gilbert, 1992). 7e.devbio.com /article.php?ch=18&id=180   (3701 words)

Carl S. Thummel Pulses of the steroid hormone ecdysone act as a critical temporal signal for the insect, triggering the major developmental transitions in the life cycle. Metamorphosis is achieved by the ecdysone activation of two divergent genetic programs: the destruction of obsolete larval tissues and their replacement by developing adult tissues. Ecdysone signaling at this stage is required for coordinated changes in cell shape that drive major morphogenetic movements, establishing the body plan of the first instar larva. www.hhmi.org /research/investigators/thummel.html   (1162 words)

Eccles Institute of Human Genetics - Carl S. Thummel Ecdysone is the key signal that triggers the major postembryonic transitions during the life cycle of the fly. During metamorphosis, ecdysone signals the destruction of most of the tissues that the larva used for its survival and growth. Baker, K.D., Warren, J.T., Thummel, C.S., Gilbert, L.I., and D.J. Mangelsdorf (2000) Transcriptional activation of the Drosophila ecdysone receptor by insect and phytoecdysteroids. www.genetics.utah.edu /faculty/cthummel.html   (1500 words)

JIS: Tschinkel 2.12.2002 For the latter species it was then conjectured that in response to the high ecdysone titers in circulation a humoral factor such as allatostatin was released by the brain or that ecdysone inhibited the corpora allata (Friedel et al., 1980) by acting like an allatostatin. The exact concentration of ecdysone in these experimental animals is, however, not known, but one may assume that it was rather high, since in a substantial number of these adult females the epidermis produced a new cuticle within 5 to 7 weeks. However, ecdysone titer determinations for the adults of several species have been made and evidence is given in a few cases that ecdysone originates in vitellogenic ovaries of these adult animals. www.insectscience.org /2.20   (5381 words)

JIS: Tschinkel 2.12.2002 Ecdysone (E) and 20-hydroxyecdysone (20HE) levels, expression of the Yp3 gene and oogenesis were studied in a wild type, stress responsive, strain (101) and in a mutant, stress nonresponsive, strain (147) of Drosophila virilis under normal and stress conditions. The isolation and cloning of the ecdysone receptor combined with the identification of ecdysone-responsive elements (EREs) in target genes that are bound by the activated ecdysone receptor complex has opened new possibilities for the development of cell-line based screening systems for compounds with ecdysone agonist or antagonist activity. Ecdysone mimetic compounds were identified in extracts from spinach and Chenopodium album of which one was purified and characterized by mass spectrometry as 20E. www.insectscience.org /2.16   (15430 words)

Interactive Fly, Drosophila Ecdysone binds a heterodimeric protein receptor, composed of an Ecdysone receptor subunit (EcR) and an RXR-like subunit encoded by the ultraspiracle (usp) gene. One difference between the response to ecdysone in S2 cells and animals is that, in S2 cells, let-7 expression begins about 24 h after the addition of ecdysone, while in animals, let-7 expression begins about 4 h after the pulse of ecdysone at the end of the third larval stage. Components of the pathway mediating let-7 activation by ecdysone in S2 cells may be relatively limiting compared to intact animals, and perhaps the concentration of ecdysone needed to activate let-7 expression when applied to S2 cells may not be as effective as that in vivo. www.sdbonline.org /fly/dbzhnsky/let7-1.htm   (1867 words)

Yale > Molecular Cellular and Developmental Biology > Graduate Program In the fruit fly Drosophila melanogaster, the steroid insect molting hormone ecdysone is responsible for the regulation of developmental events including the dramatic metamorphosis from the worm-like larva to the winged adult. We have focused on the molecular action of ecdysone, and of a gene, E75, which is one of the primary targets of the ecdysone receptor. Within follicle cells, E75 is regulated both by ecdysone and the dorsal-ventral polarity system, and may be required for the integration of spatial and temporal signals in the specification of dorsal follicle cell fates. www.biology.yale.edu /facultystaff/segraves.html   (752 words)

Reflex Ecdysone   (Site not responding. Last check: 2007-10-18) Ecdysone is is a non-hormonal anabolic supplement whose ingredients have been shown to increase muscle mass with no undesirable side effects. Studies carried out on ecdysone show that it has positive effects on work capacity, immune function, lean body mass and fat loss, but especially so when combined with a high protein diet. A study was carried out on 78 highly trained athletes to asses the effects of ecdysone on muscle mass and fat mass. www.heroesmuscle.co.uk /item250.htm   (195 words)

Ecdysone pathway is required for furrow progression in the developing Drosophila eye -- Brennan et al. 125 (14): 2653 ... Ecdysone pathway is required for furrow progression in the developing Drosophila eye -- Brennan et al. Ecdysone pathway is required for furrow progression in the developing Drosophila eye reporter of transcriptional activity of the Ecdysone Receptor and of the Z1 isoform of the Broad Complex, are localized in and close to the furrow. dev.biologists.org /cgi/content/abstract/125/14/2653   (553 words)

[No title]   (Site not responding. Last check: 2007-10-18) The early puffs regressed immediately after ecdysone was removed because in order for transcription to occur, the gene needs constant stimulation from ecdysone. The ecdysone is needed to turn on gene transcription to produce more of the proteins from the early puff genes. The late puffs arose prematurely because the early puffs were unable to continue transcription because of the removal of the ecdysone. www.susqu.edu /students/w/wing/cellproblemset7.doc   (418 words)

[No title]   (Site not responding. Last check: 2007-10-18) The insect ecdysone receptor (EcR) heterodimerizes with Ultraspiracle (USP), the insect homologue of the mammalian RXR, and binds ecdysteroids and ecdysone receptor response elements and activate transcription of ecdysone responsive genes. activated by a second DNA construct comprising an ecdysone receptor that, in the presence of a ligand therefor, and optionally in the presence of a receptor capable of acting as a silent partner, binds to the ecdysone response element to induce gene expression. With the improvement in ecdysone receptor-based gene regulation systems there is an increase in their use in various applications resulting in increased demand for ligands with higher activity than those currently exist. www.wipo.int /cgi-pct/guest/getbykey5?KEY=05/17126.050224&ELEMENT_SET=DECL   (7071 words)

Drosophila Eversion Eversion was seen as early as 2 hours after ecdysone exposure, while eversion further progressed until 24 hours of ecdysone exposure. In the seocnd replication of the experiment, antibiotics were added to the ecdysone solution and a higher concentration range of ecdysone was used. It was important to use a range of concentration because the ecdysone solution might also become deactivated as it ages. www.swarthmore.edu /NatSci/sgilber1/DB_lab/drosophila/dros_004.html   (264 words)

MOCB Faculty: Dr. Eric H. Baehrecke The diversity of responses to a hormone may reach its extreme in insects, where the steroid 20-hydroxyecdysone (ecdysone) affects numerous physiological and developmental functions. Pulses of ecdysone trigger genetic regulatory hierarchies that mediate the dramatic metamorphosis from a larva to an adult. who is induced by ecdysone at the onset of metamorphosis, when it is expressed in the presumptive adult muscle cells associated with appendages. www.life.umd.edu /grad/mocb/faculty/baehrecke.html   (394 words)

Ecdysone-induced expression of the caspase DRONC during hormone-dependent programmed cell death in Drosophila is ... Ecdysone induces caspase-dependent cell death in l(2)mbn cells. Cells were then treated with 10 µM ecdysone for 24 h or left untreated (0). Ecdysone inducible complexes a, b, and I are indicated. www.jcb.org /cgi/content/full/157/6/985   (7082 words)

Faculty - Molecular Biology Program - Bioscience Graduate Studies - University of Utah Pulses of ecdysone act as a critical temporal signal for the insect, triggering the major developmental transitions in the life cycle. During metamorphosis, ecdysone signals the destruction of tissues that the larva used for its survival and growth. This observation raises the important question of whether the remaining orphan receptors have ligands and, if so, how these novel hormones and their receptors contribute to growth and development. www.bioscience.utah.edu /mb/mbFaculty/thummel/thummel.html   (910 words)

ARS | Publication request: Development of a Two-Hybrid Ecdysone Receptor-Based Gene Switch for Plants   (Site not responding. Last check: 2007-10-18) An ecdysone receptor-based gene switch is one of the best gene regulation systems available, because the chemical (methoxyfenozide) required for its regulation is registered for field use. The major limitation of this gene switch is that it requires M concentration of the ligand for activation. Constructs were made by fusing the D, E and F domains of the ecdysone receptor to the GAL4 DNA-binding domain and the E and F domains of the retinoid x receptor (RxR) to the VP16 activation domain. www.ars.usda.gov /research/publications/Publications.htm?seq_no_115=166400&pf=1   (421 words)

Interactive Fly, Drosophila is a temperature-sensitive mutation in the ecdysoneless gene (Garen, 1977) that impairs the biosynthesis of ecdysone at restrictive temperature (29°C). After washes to remove ecdysone circulating in the hemolymph, organs were cultured in Schneider's medium with or without 5 microM ecdysone, for various lengths of time (0-20 h). S2 cells were incubated in the presence of ecdysone at a final concentration of 5 microM for 6-62 h, and harvested every 6 h. www.sdbonline.org /fly/dbzhnsky/let7-3.htm   (7999 words)

Eccles Institute of Human Genetics A study conducted by University of Utah genetics researchers shows that the steroid hormone ecdysone controls an important phase in the embryonic development of insects, providing an unexpected parallel with the role of the hormone in controlling metamorphosis. Thummel said that the source of ecdysone in the early embryo, prior to the development of the insect endocrine organ, has always baffled scientists. This role for ecdysone is unexpectedly similar to the role that the hormone plays in converting the body plan of the larva into an adult insect during metamorphosis, uncovering a new hormone-dependent phase in the insect life cycle. www.genetics.utah.edu /news/sc6press23.html   (418 words)

The E23 early gene of Drosophila encodes an ecdysone-inducible ATP-binding cassette transporter capable of repressing ... The hours and stages of development, as well as the developmental periods associated with ecdysone pulses, are indicated above the lanes. ecdysone pulse; this late embryonic expression is not observed M ecdysone for the number of hours indicated, after which total RNA was isolated and used to produce Northern blots hybridized with gene-specific probes as shown. www.pnas.org /cgi/content/full/97/17/9519   (4937 words)

"Learning the Rules": Woodward's Flies Are Model Organisms for Genetic Research When ecdysone is absent, these receptors "turn off" the activity within a specific gene. But when ecdysone is dumped into circulation and docks, space-station style, with its hormone receptor, the gene becomes active; tuned in and turned on, so to speak. At the beginning of metamorphosis, that pulse of ecdysone doesn't tell the structure to die, and the salivary glands remain to do their job; at the end of metamorphosis, the same signal, a pulse of ecdysone, does tell the cells to die and the salivary glands disappear. www.mtholyoke.edu /offices/comm/csj/012502/flies.shtml   (1584 words)

Steroid and Neuronal Regulation of Ecdysone Receptor Expression during Metamorphosis of Muscle in the Moth, Manduca ... Steroid and Neuronal Regulation of Ecdysone Receptor Expression during Metamorphosis of Muscle in the Moth, Manduca sexta -- Hegstrom et al. of an ecdysone receptor homolog from Manduca sexta and the developmental ecdysone receptor, MHR3, dopa decarboxylase, and a larval cuticle www.jneurosci.org /cgi/content/full/18/5/1786   (5779 words)

Re: What exactly happens during metamorphisis of a butterfly? High amounts of JH in the presence of Ecdysone results in the maintainance of larval epidermal cells and elicits no change in the imaginal disks. Moderate amounts of JH in the presence of Ecdysone (ie, a drop in JH) results in pupation--the formation of a crysalis. If only Ecdysone is present (ie, JH production ends), the epidermal cells are programmed for death, the imaginal disk cells proliferate and create adult structures, and the pupa becomes an adult. www.madsci.org /posts/archives/dec96/848500389.Gb.r.html   (449 words)

An Enhancer Trap Screen for Ecdysone-Inducible Genes Required for Drosophila Adult Leg Morphogenesis -- Gates and ... To identify mutations in genes that are regulated by ecdysone Leg imaginal discs were dissected from mid-third instar larvae (-18 hr relative to puparium formation) and late third instar larvae (-4 hr relative to puparium formation) and stained for lacZ expression. Vulcan and bancal transcription is inducible by ecdysone. www.genetics.org /cgi/content/full/156/4/1765   (7091 words)

[No title] The synthetic receptor is constitutively expressed as a heterodimer consisting of the ecdysone receptor (EcR) and the retinoid-X-receptor (RXR). The heterodimeric ecdysone receptor remains bound to five copies of the E/GRE recognition element located upstream of a minimal promoter in the inducible expression cassete. The inductible promoter remains transcriptionally silent until induction with the ecdysone analogs muristerone A or ponasterone A. Interaction between the inducer and the EcR ligand-binding domain results in the recruitment of coacivator(s) and, thus, transcriptional activation that can reach over three orders of magnitude. www.stratagene.com /products/displayProduct.aspx?pid=247   (1174 words)

AEN: Meeting Abstracts   (Site not responding. Last check: 2007-10-18) Manduca sexta ecdysone receptor isoform A (Msex-EcR-A) Msex-EcR-B1 Manduca sexta ultraspiracle isoform 1 (Msex-USP-1) Bombyx mori ecdysone receptor isoform A (Bmor EcR-A) Bmor EcR-B1 Bombyx mori ecdysone receptor mRNA Sonobe, H.; Horike, N. (1998) Ecdysone 20-monooxygenase in eggs of the silkworm, Bombyx mori. www.sciref.org /aen/issue1/meetref.htm   (2457 words)

Ecdysone receptor directly binds the promoter of the Drosophila caspase dronc, regulating its expression in specific ... Ecdysone receptor directly binds the promoter of the Drosophila caspase dronc, regulating its expression in specific tissues -- Cakouros et al. (B) 9 µg of nuclear extracts prepared from l(2)mbn cells treated with ecdysone for 6 h was incubated with the droncEcRBE or the EcRBE mutant probe for 20 min in the presence of 2 µl of EcR common, EcR-B1, or EcR-A antibody. Ecdysone binds its heterodimeric receptor EcR–Usp and activates dronc expression in specific tissues by directly interacting with an EcRBE in the promoter. www.jcb.org /cgi/content/full/165/5/631   (6172 words)

ARS | Publication request: Localization of Myoinhibitory Peptide Immunoreactivity in Manduca Sexta: Indications That ...   (Site not responding. Last check: 2007-10-18) Interpretive Summary: Molting in insects is controlled by a hormone known as ecdysone, which is secreted by glands in the thorax. Prior to molting, ecdysone is rapidly secreted by these glands for a period of time, after which secretion abruptly ceases. In addition, we have found that MIP immunoreactivity is co-localized with that of crustacean cardioactive peptide (CCAP) in the interneurons designated 704; these peptides appear to be co-released at the time of ecdysis. www.ars.usda.gov /research/publications/publications.htm?SEQ_NO_115=143573   (496 words)

Transcription Activation by the Ecdysone Receptor (EcR/USP): Identification of Activation Functions -- Hu et al. 17 ... Hannan GN, Hill RJ 1997 Cloning and characterization of LcEcR: a functional ecdysone receptor from the sheep blowfly Lucilia cuprina. Swevers L, Drevet JR, Lunke MD, Iatrou K 1995 The silkmoth homolog of the Drosophila ecdysone receptor (B1 isoform): cloning and analysis of expression during follicular cell differentiation. I-iodoponasterone A is a potent ecdysone and a sensitive radioligand for ecdysone receptors. mend.endojournals.org /cgi/content/full/17/4/716   (8706 words)

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