scholarly journals Functions of the ecdysone receptor isoform-A in the hemimetabolous insect Blattella germanica revealed by systemic RNAi in vivo

2006 ◽  
Vol 297 (1) ◽  
pp. 158-171 ◽  
Author(s):  
Josefa Cruz ◽  
Daniel Mané-Padrós ◽  
Xavier Bellés ◽  
David Martín
Keyword(s):  
Blattella Germanica ◽  
Ecdysone Receptor ◽  
Hemimetabolous Insect ◽  
Systemic Rnai

scholarly journals Isoform specific control of gene activity in vivo by the Drosophila ecdysone receptor

2003 ◽  
Vol 120 (8) ◽  
pp. 909-918 ◽  
Author(s):  
Margrit Schubiger ◽  
Shuichiro Tomita ◽  
Carl Sung ◽  
Steven Robinow ◽  
James W Truman
Keyword(s):  
Gene Activity ◽  
Ecdysone Receptor ◽  
Specific Control

scholarly journals A COUP-TF/Svp homolog is highly expressed during vitellogenesis in the mosquito Aedes aegypti

2002 ◽  
Vol 29 (2) ◽  
pp. 223-238 ◽  
Author(s):  
K Miura ◽  
J Zhu ◽  
NT Dittmer ◽  
L Chen ◽  
AS Raikhel
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Fat Body ◽  
Sequence Similarity ◽  
Amino Acid Sequence Similarity ◽  
Receptor Complex ◽  
Ecdysone Receptor ◽  
Ecdysteroid Receptor

In the mosquito Aedes aegypti, vitellogenesis is activated via an ecdysteroid hormonal cascade initiated by a blood meal. The functional ecdysone receptor is a heterodimer composed of the ecdysone receptor (EcR) and ultraspiracle, the homolog of the retinoid X receptor. The precise tuning of this hormonal response requires participation of both positive and negative transcriptional regulators. In Drosophila, Svp, a homolog of chicken ovalbumin upstream promoter transcription factor (COUP-TF), inhibits ecdysone receptor complex-mediated transactivation in vitro and in vivo. Here we report the cloning and characterization of the Svp homolog in mosquito Aedes aegypti, AaSvp. It possesses a high degree of amino acid sequence similarity to the members of the COUP-TF/Svp subfamily. AaSvp transcripts and protein are present in the fat body at high levels from the state of arrest to about 60 h post blood meal. AaSvp binds strongly to a variety of direct repeats of the sequence AGGTCA, but weakly to inverted repeats such as hsp27 EcRE. Transient transfection assays in Drosophila S2 cells showed that AaSvp was able to repress 20-hydroxyecdysone (20E)-dependent transactivation mediated by the mosquito ecdysteroid receptor complex. These data suggest that AaSvp negatively regulates the 20E signaling in the fat body during mosquito vitellogenesis.

scholarly journals Adenovirus-Mediated Inducible Gene Expression in Vivo by a Hybrid Ecdysone Receptor

2000 ◽  
Vol 1 (2) ◽  
pp. 159-164 ◽  
Author(s):  
Uta C Hoppe ◽  
Eduardo Marbán ◽  
David C Johns
Keyword(s):  
Gene Expression ◽  
Ecdysone Receptor ◽  
Inducible Gene Expression ◽  
Inducible Gene

The RXR homolog ultraspiracle is an essential component of the Drosophila ecdysone receptor

Development ◽  
1998 ◽  
Vol 125 (23) ◽  
pp. 4709-4717 ◽  
Author(s):  
B.L. Hall ◽  
C.S. Thummel
Keyword(s):  
Ecdysone Receptor ◽  
Transcriptional Responses ◽  
Developmental Transitions ◽  
Specific Manner ◽  
Puparium Formation ◽  
Regulated Gene Expression ◽  
Larval Molt ◽  
Third Instar Larvae

Pulses of the steroid hormone ecdysone function as key temporal signals during insect development, coordinating the major postembryonic developmental transitions, including molting and metamorphosis. In vitro studies have demonstrated that the EcR ecdysone receptor requires an RXR heterodimer partner for its activity, encoded by the ultraspiracle (usp) locus. We show here that usp exerts no apparent function in mid-third instar larvae, when a regulatory hierarchy prepares the animal for the onset of metamorphosis. Rather, usp is required in late third instar larvae for appropriate developmental and transcriptional responses to the ecdysone pulse that triggers puparium formation. The imaginal discs in usp mutants begin to evert but do not elongate or differentiate, the larval midgut and salivary glands fail to undergo programmed cell death and the adult midgut fails to form. Consistent with these developmental phenotypes, usp mutants show pleiotropic defects in ecdysone-regulated gene expression at the larval-prepupal transition. usp mutants also recapitulate aspects of a larval molt at puparium formation, forming a supernumerary cuticle. These observations indicate that usp is required for ecdysone receptor activity in vivo, demonstrate that the EcR/USP heterodimer functions in a stage-specific manner during the onset of metamorphosis and implicate a role for usp in the decision to molt or pupariate in response to ecdysone pulses during larval development.

scholarly journals Ecdysone receptor in the mud crab Scylla paramamosain: a possible role in promoting ovarian development

2015 ◽  
Vol 224 (3) ◽  
pp. 273-287 ◽  
Author(s):  
Jie Gong ◽  
Haihui Ye ◽  
Yinjie Xie ◽  
Yanan Yang ◽  
Huiyang Huang ◽  
...  
Keyword(s):  
Ovarian Development ◽  
Stage Iv ◽  
Mature Stage ◽  
Scylla Paramamosain ◽  
Ecdysone Receptor ◽  
Mud Crab ◽  
Follicular Cells ◽  
Vitellogenic Stage

In arthropods, it is known that ecdysteroids regulate molting, limb regeneration, and reproduction through activation of the ecdysone receptor (EcR). However, the ecdysteroid signaling pathway for promotion of ovarian development in crustaceans is still unclear. In this study, three cDNA isoforms of EcR were cloned from the mud crab Scylla paramamosain. qRT-PCR revealed that the SpEcR mRNA was abundant in the eyestalk, ovary and epidermis. During ovarian development, the SpEcR transcripts increased from stage I (undeveloped stage) and reached a peak at stage IV (late vitellogenic stage) before dropping to a lower level at stage V (mature stage). Meanwhile, levels of 20-hydroxyecdysone (20E) in the hemolymph, detected by HPLC-MS, displayed a similar pattern of increase with ovarian development. Results from in situ hybridization indicated that SpEcR mRNA was present in the follicular cells during vitellogenesis. Results from in vivo experiments revealed that 20E at 0.2 μg/g body weight significantly stimulated the expression of SpEcR and vitellogenin (SpVg) in female crabs during the early vitellogenic stage but not during the previtellogenic stage. This was confirmed by results from in vitro experiments which indicated that SpEcR and SpVg expression levels were significantly upregulated in early vitellogenic ovarian explants incubated with 5.0 μM 20E at 3 and 6 h but not in previtellogenic ovarian explants. Finally, results from in vitro gene silencing experiments indicated that the expression of SpEcR and SpVg in the ovary was significantly inhibited by SpEcR dsRNA. All these results together indicated that in S. paramamosain, 20E, and SpEcR, located in the follicular cells, play important roles in the promotion of ovarian development via regulating the expression of SpVg.

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