Ecdysone receptor expression in the CNS correlates with stage-specific responses to ecdysteroids during Drosophila and Manduca development

Development ◽  
1994 ◽  
Vol 120 (1) ◽  
pp. 219-234 ◽  
Author(s):  
J.W. Truman ◽  
W.S. Talbot ◽  
S.E. Fahrbach ◽  
D.S. Hogness
Keyword(s):  
Optic Lobe ◽  
Receptor Expression ◽  
Protein Isoforms ◽  
Mushroom Bodies ◽  
Ecdysone Receptor ◽  
Adult Form ◽  
Receptor Isoforms ◽  
Different Types ◽  
Hormonal Signal ◽  
Adult Transformation

In insects, the ecdysteroids act to transform the CNS from its larval to its adult form. A key gene in this response is the ecdysone receptor (EcR), which has been shown in Drosophila to code for 3 protein isoforms. Two of these isoforms, EcR-A and EcR-B1, are prominently expressed in the CNS and we have used isoform-specific antibodies to examine their fluctuations through postembryonic life. EcR expression at the onset of metamorphosis is extremely diverse but specific patterns of EcR expression correlate with distinct patterns of steroid response. Most larval neurons show high levels of EcR-B1 at the start of metamorphosis, a time when they lose larval features in response to ecdysteroids. Earlier, during the larval molts, the same cells have no detectable receptors and show no response to circulating ecdysteroids; later, during the pupal-adult transformation, they switch to EcR-A expression and respond by maturing to their adult form. During the latter period, a subset of the larval neurons hyperexpress EcR-A and these cells are fated to die after the emergence of the adult. The stem cells for the imaginal neurons show prominent EcR-B1 expression during the last larval stage correlated with their main proliferative period. Most imaginal neurons, by contrast, express only EcR-A when they subsequently initiate maturation at the start of metamorphosis. The imaginal neurons of the mushroom bodies are unusual amongst imaginal neurons in expressing the B1 isoform at the start of metamorphosis but they also show regressive changes at this time as they lose their larval axons. Imaginal neurons of the optic lobe show a delayed expression of EcR-B1 through the period when cell-cell interactions are important for establishing connections within this region of the CNS. Overall, the appearance of the two receptor isoforms in cells correlates with different types of steroid responses: EcR-A predominates when cells are undergoing maturational responses whereas EcR-B1 predominates during proliferative activity or regressive responses. The heterogeneity of EcR expression at the start of metamorphosis presumably reflects the diverse origins and requirements of the neurons that nevertheless are all exposed to a common hormonal signal.

Drosophila EcR-B ecdysone receptor isoforms are required for larval molting and for neuron remodeling during metamorphosis

Development ◽  
1998 ◽  
Vol 125 (11) ◽  
pp. 2053-2062 ◽  
Author(s):  
M. Schubiger ◽  
A.A. Wade ◽  
G.E. Carney ◽  
J.W. Truman ◽  
M. Bender
Keyword(s):  
Nervous System ◽  
Wide Spectrum ◽  
Control Cell ◽  
P Element ◽  
Ecdysone Receptor ◽  
Larval Stages ◽  
Receptor Isoforms ◽  
Imprecise Excision ◽  
Cell Type Specific ◽  
Insect Central Nervous System

During the metamorphic reorganization of the insect central nervous system, the steroid hormone 20-hydroxyecdysone induces a wide spectrum of cellular responses including neuronal proliferation, maturation, cell death and the remodeling of larval neurons into their adult forms. In Drosophila, expression of specific ecdysone receptor (EcR) isoforms has been correlated with particular responses, suggesting that different EcR isoforms may govern distinct steroid-induced responses in these cells. We have used imprecise excision of a P element to create EcR deletion mutants that remove the EcR-B promoter and therefore should lack EcR-B1 and EcR-B2 expression but retain EcR-A expression. Most of these EcR-B mutant animals show defects in larval molting, arresting at the boundaries between the three larval stages, while a smaller percentage of EcR-B mutants survive into the early stages of metamorphosis. Remodeling of larval neurons at metamorphosis begins with the pruning back of larval-specific dendrites and occurs as these cells are expressing high levels of EcR-B1 and little EcR-A. This pruning response is blocked in the EcR-B mutants despite the fact that adult-specific neurons, which normally express only EcR-A, can progress in their development. These observations support the hypothesis that different EcR isoforms control cell-type-specific responses during remodeling of the nervous system at metamorphosis.

scholarly journals Ecdysone receptor isoforms play distinct roles in larval–pupal–adult transition in Leptinotarsa decemlineata

2019 ◽  
Vol 27 (3) ◽  
pp. 487-499 ◽  
Author(s):  
Qing‐Yu Xu ◽  
Pan Deng ◽  
Qiong Zhang ◽  
Ang Li ◽  
Kai‐Yun Fu ◽  
...  
Keyword(s):  
Leptinotarsa Decemlineata ◽  
Ecdysone Receptor ◽  
Adult Transition ◽  
Receptor Isoforms

Different interactions of cardiac and skeletal muscle ryanodine receptors with FK-506 binding protein isoforms

1997 ◽  
Vol 272 (5) ◽  
pp. C1726-C1733 ◽  
Author(s):  
S. Barg ◽  
J. A. Copello ◽  
S. Fleischer
Keyword(s):  
Skeletal Muscle ◽  
Lipid Bilayers ◽  
Single Channel ◽  
Ryanodine Receptors ◽  
Protein Isoforms ◽  
Channel Activity ◽  
Functional Interaction ◽  
Fk 506 ◽  
Receptor Isoforms ◽  
Functional Consequences

In the present study, we compare functional consequences of dissociation and reconstitution of binding proteins FKBP12 and FKBP12.6 with ryanodine receptors from cardiac (RyR2) and skeletal muscle (RyR1). The skeletal muscle RyR1 channel became activated on removal of endogenously bound FKBP12, consistent with previous reports. Both FKBP12 and FKBP12.6 rebind to FKBP-depleted RyR1 and restore its quiescent channel behavior by altering ligand sensitivity, as studied by single-channel recordings in planar lipid bilayers, and macroscopic behavior of the channels (ryanodine binding and net energized Ca2- uptake). By contrast, removal of FKBP12.6 from the cardiac RyR2 did not modulate the function of the channel using the same types of assays as for RyR1. FKBP12 or FKBP12.6 had no effect on channel activity of FKBP12.6-depleted cardiac RyR2, although FKBP12.6 rebinds. Our studies reveal important differences between the two ryanodine receptor isoforms with respect to their functional interaction with FKBP12 and FKBP12.6.

scholarly journals Interaction of the N-terminus of ecdysone receptor isoforms with the ligand-binding domain

2011 ◽  
Vol 332 (1-2) ◽  
pp. 293-300 ◽  
Author(s):  
Ch. Tremmel ◽  
M. Schaefer ◽  
A. Azoitei ◽  
H. Ruff ◽  
M. Spindler-Barth
Keyword(s):  
Ligand Binding ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Ecdysone Receptor ◽  
Receptor Isoforms ◽  
N Terminus

scholarly journals Serotonergic modulation of visual neurons in Drosophila melanogaster

2019 ◽  
Author(s):  
Maureen M Sampson ◽  
Katherine M Myers Gschweng ◽  
Ben J Hardcastle ◽  
Shivan L Bonanno ◽  
Tyler R Sizemore ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Information Processing ◽  
Visual Processing ◽  
Serotonin Receptors ◽  
Visual Information ◽  
Optic Lobe ◽  
Receptor Expression ◽  
Serotonergic Neurons ◽  
Visual Neurons ◽  
Kinetics Of

AbstractSensory systems rely on neuromodulators, such as serotonin, to provide flexibility for information processing in the face of a highly variable stimulus space. Serotonergic neurons broadly innervate the optic ganglia of Drosophila melanogaster, a widely used model for studying vision. The role for serotonergic signaling in the Drosophila optic lobe and the mechanisms by which serotonin regulates visual neurons remain unclear. Here we map the expression patterns of serotonin receptors in the visual system, focusing on a subset of cells with processes in the first optic ganglion, the lamina, and show that serotonin can modulate visual responses. Serotonin receptors are expressed in several types of columnar cells in the lamina including 5-HT2B in lamina monopolar cell L2, required for the initial steps of visual processing, and both 5-HT1A and 5-HT1B in T1 cells, whose function is unknown. Subcellular mapping with GFP-tagged 5-HT2B and 5-HT1A constructs indicates that these receptors localize to layer M2 of the medulla, proximal to serotonergic boutons, suggesting that the medulla is the primary site of serotonergic regulation for these neurons. Serotonin increases intracellular calcium in L2 terminals in layer M2 and alters the kinetics of visually induced calcium transients in L2 neurons following dark flashes. These effects were not observed in flies without a functional 5-HT2B, which displayed severe differences in the amplitude and kinetics of their calcium response to both dark and light flashes. While we did not detect serotonin receptor expression in L1 neurons, they also undergo serotonin-induced calcium changes, presumably via cell non-autonomous signaling pathways. We provide the first functional data showing a role for serotonergic neuromodulation of neurons required for initiating visual processing in Drosophila and establish a new platform for investigating the serotonergic neuromodulation of sensory networks.Author SummarySerotonergic neurons innervate the Drosophila melanogaster eye, but the function of serotonergic signaling is not known. We found that serotonin receptors are expressed in all neuropils of the optic lobe and identify specific neurons involved in visual information processing that express serotonin receptors. We then demonstrate that activation of these receptors can alter how visual information is processed. These are the first data suggesting a functional role for serotonergic signaling in Drosophila vision. This study contributes to the understanding of serotonin biology and modulation of sensory circuits.

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