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Hansen BH, Tarrant AM, Lenz PH, Roncalli V, Almeda R, Broch OJ, Altin D, Tollefsen KE. Effects of petrogenic pollutants on North Atlantic and Arctic Calanus copepods: From molecular mechanisms to population impacts. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 267:106825. [PMID: 38176169 DOI: 10.1016/j.aquatox.2023.106825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/19/2023] [Accepted: 12/27/2023] [Indexed: 01/06/2024]
Abstract
Oil and gas industries in the Northern Atlantic Ocean have gradually moved closer to the Arctic areas, a process expected to be further facilitated by sea ice withdrawal caused by global warming. Copepods of the genus Calanus hold a key position in these cold-water food webs, providing an important energetic link between primary production and higher trophic levels. Due to their ecological importance, there is a concern about how accidental oil spills and produced water discharges may impact cold-water copepods. In this review, we summarize the current knowledge of the toxicity of petroleum on North Atlantic and Arctic Calanus copepods. We also review how recent development of high-quality transcriptomes from RNA-sequencing of copepods have identified genes regulating key biological processes, like molting, diapause and reproduction in Calanus copepods, to suggest linkages between exposure, molecular mechanisms and effects on higher levels of biological organization. We found that the available ecotoxicity threshold data for these copepods provide valuable information about their sensitivity to acute petrogenic exposures; however, there is still insufficient knowledge regarding underlying mechanisms of toxicity and the potential for long-term implications of relevance for copepod ecology and phenology. Copepod transcriptomics has expanded our understanding of how key biological processes are regulated in cold-water copepods. These advances can improve our understanding of how pollutants affect biological processes, and thus provide the basis for new knowledge frameworks spanning the effect continuum from molecular initiating events to adverse effects of regulatory relevance. Such efforts, guided by concepts such as adverse outcome pathways (AOPs), enable standardized and transparent characterization and evaluation of knowledge and identifies research gaps and priorities. This review suggests enhancing mechanistic understanding of exposure-effect relationships to better understand and link biomarker responses to adverse effects to improve risk assessments assessing ecological effects of pollutant mixtures, like crude oil, in Arctic areas.
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Affiliation(s)
| | - Ann M Tarrant
- Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, United States
| | - Petra H Lenz
- University of Hawai'i at Mānoa, Honolulu, HI, 96822, United States
| | | | - Rodrigo Almeda
- EOMAR-ECOAQUA, University of Las Palmas de Gran Canaria (ULPGC), Canary Islands, Spain
| | - Ole Jacob Broch
- SINTEF Ocean, Fisheries and New Biomarine Industry, 7465 Trondheim, Norway
| | - Dag Altin
- BioTrix, 7020 Trondheim, Norway; Norwegian University of Science and Technology, Research Infrastructure SeaLab, 7010 Trondheim, Norway
| | - Knut Erik Tollefsen
- Norwegian Institute for Water Research (NIVA), 0579 Oslo, Norway; Norwegian University of Life Sciences (NMBU), N-1433 Ås, Norway
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Zheng Y, Zhang W, Xiong Y, Wang J, Jin S, Qiao H, Jiang S, Fu H. Dual roles of CYP302A1 in regulating ovarian maturation and molting in Macrobrachium nipponense. J Steroid Biochem Mol Biol 2023; 232:106336. [PMID: 37247747 DOI: 10.1016/j.jsbmb.2023.106336] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/16/2023] [Accepted: 05/26/2023] [Indexed: 05/31/2023]
Abstract
CYP302A1 is a member of the Halloween genes in the cytochrome P450 supergene family, which play an important regulatory role in the synthesis of 20-hydroxyecdysone (20E) in crustaceans and insects. In this study, we found that the Mn-CYP302A1sequence included typical CYP450 conserved domains. Phylogenic showed that it is closely related to crustaceans and insects. q-PCR analysis indicated that Mn-CYP302A1 was highly expressed in the ovaries and peaked before ovarian maturation. Mn-CYP302A1 expression was higher at the post-larval stage of day 15 than at other stages of embryogenesis. In situ hybridization indicated that Mn-CYP302A1 was mainly distributed in the nucleus, yolk granules, cell membrane and cytoplasm To further establish the function of CYP302A1, a 21-day RNA interference experiment was conducted. On day 16, the Gonad Somatic Index of the control group and the experimental group showed significant differences, with GSI of 11.72% in the control group and 3.21% in the experimental group. The cumulative proportion of the second entry into stage O-Ⅲ was 100% in the control group, while it was 41.67% in the experimental group on day 21. The ecdysone content was 8.91nmol/L in the control group and 6.11nmol/L in the experimental group on day 9. A significant difference in the molting proportion between the control group and the experimental group was also observed (49% in the control group and 34% in the experimental group) on day 16. Statistical results showed that the average molting cycle of the control group was 14.5 days, while that of the experimental group was 16.5 days. However, the morphological structure of ovarian tissue did not abnormal change. Therefore, the results of this study suggest that Mn-CYP302A1 can promote ovarian maturation and molting in female M. nipponense.
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Affiliation(s)
- Yalu Zheng
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China
| | - Wenyi Zhang
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China
| | - Yiwei Xiong
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China
| | - Jisheng Wang
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China
| | - Shubo Jin
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China
| | - Hui Qiao
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Sufei Jiang
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Hongtuo Fu
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
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3
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Zhang C, Wan B, Jin MR, Wang X, Wei YJ, Zhong L, Xia B. Inhibition of ecdysone receptor (DcEcR) and ultraspiracle (DcUSP) expression in Diaphorina citri increased susceptibility to pesticides. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 194:105518. [PMID: 37532332 DOI: 10.1016/j.pestbp.2023.105518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 06/15/2023] [Accepted: 07/04/2023] [Indexed: 08/04/2023]
Abstract
Diaphorina citri Kuwayama is of great concern because of its ability to transmit devastating citrus greening illness (Huanglongbing). One strategy for controlling HLB may involve limiting the spread of D. citri. Insecticides using dsRNA target genes may be a useful option to control D. citri. The ecdysone receptor (EcR) and ultraspiracle (USP) are crucial for the growth and reproduction of insects. This study identified the genes for D. citri ecdysone receptor (DcEcR) and ultraspiracle (DcUSP). According to the qPCR data, DcUSP peaked at the 5th-instar nymph stage, while DcEcR peaked at the adult stage. Females expressed DcEcR and DcUSP at much higher levels than males. RNAi was used to examine DcEcR and DcUSP function. The findings demonstrated that inhibition of DcEcR and DcUSP delayed nymph development and decreased survival and eclosion rates. dsEcR caused adults to develop deformed wings, and dsUSP caused nymphs to wither and die. Female adult ovaries developed slowly, and the females laid fewer eggs. Additionally, DcEcR and DcUSP were inhibited, increasing D. citri susceptibility to pesticides. These findings suggest that DcEcR and DcUSP are critical for D. citri development, growth, and reproduction and may serve as potential targets for D. citri management.
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Affiliation(s)
- Cong Zhang
- School of Life Sciences, Nanchang University, Nanchang 330031, Jiangxi, China
| | - Bin Wan
- School of Life Sciences, Nanchang University, Nanchang 330031, Jiangxi, China
| | - Meng-Ru Jin
- School of Life Sciences, Nanchang University, Nanchang 330031, Jiangxi, China
| | - Xi Wang
- Development & Service Center for Agriculture and Rural Industry of Jiangxi Province, China
| | - Yu-Jing Wei
- School of Life Sciences, Nanchang University, Nanchang 330031, Jiangxi, China
| | - Ling Zhong
- Development & Service Center for Agriculture and Rural Industry of Jiangxi Province, China
| | - Bin Xia
- School of Life Sciences, Nanchang University, Nanchang 330031, Jiangxi, China.
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Yuan H, Qiao H, Fu Y, Fu H, Zhang W, Jin S, Gong Y, Jiang S, Xiong Y, Hu Y, Wu Y. RNA interference shows that Spook, the precursor gene of 20-hydroxyecdysone (20E), regulates the molting of Macrobrachium nipponense. J Steroid Biochem Mol Biol 2021; 213:105976. [PMID: 34418528 DOI: 10.1016/j.jsbmb.2021.105976] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 08/02/2021] [Accepted: 08/15/2021] [Indexed: 10/20/2022]
Abstract
The aim of this study was to explore the function of the Mn-Spook gene, which was found in the ovary transcriptome of the Oriental river prawn (Macrobrachium nipponense). The Spook gene, which is the precursor gene of 20-hydroxyecdysone (20E), plays an important role in the process of molting in many arthropods, but its function in M. nipponense is unclear. We cloned the full-length Mn-Spook gene from the ovary of M. nipponense and found that it had the same conserved domains as the P450 gene of the Halloween family of genes. The Mn-Spook gene was highly expressed in ovary and gill tissue during the breeding period. During ovarian development, Mn-spook gene expression was highest at the nearly-ripe stage, and it also was highly expressed in the zoea developmental stage. Cellular localization analysis showed that Mn-Spook signals accumulated in the cytoplasmic membrane and nucleus of oocytes. Finally, we used RNA interference to evaluate the function of the Mn-Spook gene. Compared with the control group, in vivo injection of Mn-Spook dsRNA effectively downregulated the expression of Mn-Spook and the content of 20E. The molting frequency of M. nipponense in the experimental group also was significantly inhibited. These results demonstrated that the Mn-Spook gene played an important role in the molting process of M. nipponense.
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Affiliation(s)
- Huwei Yuan
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China.
| | - Hui Qiao
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Yin Fu
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, China.
| | - Hongtuo Fu
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China; Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Wenyi Zhang
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Shubo Jin
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Yongsheng Gong
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Sufei Jiang
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Yiwei Xiong
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Yuning Hu
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
| | - Yan Wu
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
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de Oliveira DAB, da Silva AV, dos Santos Niculau E. Molecular Docking of Azadirachtin in Nuclear Ecdysone Receptor. ACTA ACUST UNITED AC 2019. [DOI: 10.2174/1877946809666190320141833] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Background:
The azadirachtin is a triterpenoid associated with growth inhibition
in several kinds of insects which cause epidemic diseases like Dengue, Chikungunya
and Malaria. Azadirachtin acts by inhibiting the Ecdysone Receptor (EcR), which is responsible
from larvae phase in insects. However, the interaction between the azadirachtin
molecule and the Ecdysone Receptor is unknown. In this work, we used the program Dock
Thor to generate several azadirachtin conformations inside the EcR binding site. The ten
most stable conformations were optimized with the ONIOM approach present in the
Gaussian 09 program. The interaction energy was calculated between the azadirachtin
molecule and EcR receptor. Theoretical calculation shows that the azadirachtin molecule
interacts with the same amino acids present in the ecdysone EcR interaction. These results
will be useful to design new EcR inhibitors, which can be used in the control of some diseases
based on insect proliferations.
Objective:
To understand the interaction between the natural insecticide azadirachtin and
the Ecdysone Receptor.
Methods:
A combination of Dock Thor program with QM-MM calculation was used in order
to obtain the most favorable molecular structures.
Results:
The hydrogens bond obtained by Dock Thor Program combined with QM-MM
calculation suggest the azadirachtin interact with EcR in the same way that ecdysone molecule.
Conclusion:
The interaction mode that the molecule azadirachtin inhibits EcR in order to
avoid insect proliferation was described.
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Affiliation(s)
- Daniel Augusto Barra de Oliveira
- Curso de Quimica, Universidade Federal do Tocantins, Campus Universitario de Araguaina, Av. Paraguai, s/n - esquina com Rua Uxiramas, Araguaina, Brazil
| | - Alcedino Venancio da Silva
- Curso de Quimica, Universidade Federal do Tocantins, Campus Universitario de Araguaina, Av. Paraguai, s/n - esquina com Rua Uxiramas, Araguaina, Brazil
| | - Edenilson dos Santos Niculau
- Curso de Quimica, Universidade Federal do Tocantins, Campus Universitario de Araguaina, Av. Paraguai, s/n - esquina com Rua Uxiramas, Araguaina, Brazil
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6
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Song Y, Villeneuve DL, Toyota K, Iguchi T, Tollefsen KE. Ecdysone Receptor Agonism Leading to Lethal Molting Disruption in Arthropods: Review and Adverse Outcome Pathway Development. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4142-4157. [PMID: 28355071 PMCID: PMC6135102 DOI: 10.1021/acs.est.7b00480] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Molting is critical for growth, development, reproduction, and survival in arthropods. Complex neuroendocrine pathways are involved in the regulation of molting and may potentially become targets of environmental endocrine disrupting chemicals (EDCs). Based on several known ED mechanisms, a wide range of pesticides has been developed to combat unwanted organisms in food production activities such as agriculture and aquaculture. Meanwhile, these chemicals may also pose hazards to nontarget species by causing molting defects, and thus potentially affecting the health of the ecosystems. The present review summarizes the available knowledge on molting-related endocrine regulation and chemically mediated disruption in arthropods (with special focus on insects and crustaceans), to identify research gaps and develop a mechanistic model for assessing environmental hazards of these compounds. Based on the review, multiple targets of EDCs in the molting processes were identified and the link between mode of action (MoA) and adverse effects characterized to inform future studies. An adverse outcome pathway (AOP) describing ecdysone receptor agonism leading to incomplete ecdysis associated mortality was developed according to the OECD guideline and subjected to weight of evidence considerations by evolved Bradford Hill Criteria. This review proposes the first invertebrate ED AOP and may serve as a knowledge foundation for future environmental studies and AOP development.
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Affiliation(s)
- You Song
- Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen 21, N-0349 Oslo, Norway
- Corresponding Author: Knut Erik Tollefsen, Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, NO-0349 Oslo, Norway. Tlf.: 02348, Fax: (+47) 22 18 52 00, , You Song, Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, NO-0349 Oslo, Norway. Tlf.: 02348, Fax: (+47) 22 18 52 00,
| | | | - Kenji Toyota
- Environmental Genomics Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Taisen Iguchi
- Department of Basic Biology, Faculty of Life Science, SOKENDAI (Graduate University for Advanced Studies), Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
- Graduate School of Nanobioscience, Yokohama City University, Yokohama 236-0027, Japan
| | - Knut Erik Tollefsen
- Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen 21, N-0349 Oslo, Norway
- Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV). P.O. Box 5003, N-1432 Ås, Norway
- Corresponding Author: Knut Erik Tollefsen, Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, NO-0349 Oslo, Norway. Tlf.: 02348, Fax: (+47) 22 18 52 00, , You Song, Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, NO-0349 Oslo, Norway. Tlf.: 02348, Fax: (+47) 22 18 52 00,
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7
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Yan T, Chen H, Sun Y, Yu X, Xia L. RNA Interference of the Ecdysone Receptor Genes EcR and USP in Grain Aphid (Sitobion avenae F.) Affects Its Survival and Fecundity upon Feeding on Wheat Plants. Int J Mol Sci 2016; 17:E2098. [PMID: 27983619 PMCID: PMC5187898 DOI: 10.3390/ijms17122098] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 12/16/2022] Open
Abstract
RNA interference (RNAi) has been widely used in functional genomics of insects and received intensive attention in the development of RNAi-based plants for insect control. Ecdysone receptor (EcR) and ultraspiracle protein (USP) play important roles in molting, metamorphosis, and reproduction of insects. EcR and USP orthologs and their function in grain aphid (Sitobion avenae F.) have not been documented yet. Here, RT-PCR, qRT-PCR, dsRNA feeding assay and aphid bioassay were employed to isolate EcR and USP orthologs in grain aphid, investigate their expression patterns, and evaluate the effect of RNAi on aphid survival and fecundity, and its persistence. The results indicated that SaEcR and SaUSP exhibited similar expression profiles at different developmental stages. Oral administration of dsRNAs of SaEcR and dsSaUSP significantly decreased the survival of aphids due to the down-regulation of these two genes, respectively. The silencing effect was persistent and transgenerational, as demonstrated by the reduced survival and fecundity due to knock-down of SaEcR and SaUSP in both the surviving aphids and their offspring, even after switching to aphid-susceptible wheat plants. Taken together, our results demonstrate that SaEcR and SaUSP are essential genes in aphid growth and development, and could be used as RNAi targets for wheat aphid control.
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Affiliation(s)
- Ting Yan
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China.
| | - Hongmei Chen
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China.
| | - Yongwei Sun
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China.
| | - Xiudao Yu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China.
| | - Lanqin Xia
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China.
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Cao J, Liu Y, Yang Y, Zhang H, Li Z, Yang Q, Zhang S, Zhang Q, Liu X. Molecular characterization and functional analysis of the ultraspiracle (USP) in the oriental fruit moth Grapholita molesta (Lepidoptera: Olethreutidae). Comp Biochem Physiol B Biochem Mol Biol 2015; 190:54-62. [DOI: 10.1016/j.cbpb.2015.08.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Revised: 08/13/2015] [Accepted: 08/24/2015] [Indexed: 11/30/2022]
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9
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Xie XJ, Hsu FN, Gao X, Xu W, Ni JQ, Xing Y, Huang L, Hsiao HC, Zheng H, Wang C, Zheng Y, Xiaoli AM, Yang F, Bondos SE, Ji JY. CDK8-Cyclin C Mediates Nutritional Regulation of Developmental Transitions through the Ecdysone Receptor in Drosophila. PLoS Biol 2015. [PMID: 26222308 PMCID: PMC4519132 DOI: 10.1371/journal.pbio.1002207] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The steroid hormone ecdysone and its receptor (EcR) play critical roles in orchestrating developmental transitions in arthropods. However, the mechanism by which EcR integrates nutritional and developmental cues to correctly activate transcription remains poorly understood. Here, we show that EcR-dependent transcription, and thus, developmental timing in Drosophila, is regulated by CDK8 and its regulatory partner Cyclin C (CycC), and the level of CDK8 is affected by nutrient availability. We observed that cdk8 and cycC mutants resemble EcR mutants and EcR-target genes are systematically down-regulated in both mutants. Indeed, the ability of the EcR-Ultraspiracle (USP) heterodimer to bind to polytene chromosomes and the promoters of EcR target genes is also diminished. Mass spectrometry analysis of proteins that co-immunoprecipitate with EcR and USP identified multiple Mediator subunits, including CDK8 and CycC. Consistently, CDK8-CycC interacts with EcR-USP in vivo; in particular, CDK8 and Med14 can directly interact with the AF1 domain of EcR. These results suggest that CDK8-CycC may serve as transcriptional cofactors for EcR-dependent transcription. During the larval–pupal transition, the levels of CDK8 protein positively correlate with EcR and USP levels, but inversely correlate with the activity of sterol regulatory element binding protein (SREBP), the master regulator of intracellular lipid homeostasis. Likewise, starvation of early third instar larvae precociously increases the levels of CDK8, EcR and USP, yet down-regulates SREBP activity. Conversely, refeeding the starved larvae strongly reduces CDK8 levels but increases SREBP activity. Importantly, these changes correlate with the timing for the larval–pupal transition. Taken together, these results suggest that CDK8-CycC links nutrient intake to developmental transitions (EcR activity) and fat metabolism (SREBP activity) during the larval–pupal transition. During the larval-pupal transition in Drosophila, CDK8-CycC helps to link nutrient intake to development by activating ecdysone receptor-dependent transcription and to fat metabolism by inhibiting SREBP-activated gene expression. Arthropods are estimated to account for over 80% of animal species on earth. Characterized by their rigid exoskeletons, juvenile arthropods must periodically shed their thick outer cuticles by molting in order to grow. The steroid hormone ecdysone plays an essential role in regulating the timing of developmental transitions, but exactly how ecdysone and its receptor EcR activates transcription correctly after integrating nutritional and developmental cues remains unknown. Our developmental genetic analyses of two Drosophila mutants, cdk8 and cycC, show that they are lethal during the prepupal stage, with aberrant accumulation of fat and a severely delayed larval–pupal transition. As we have reported previously, CDK8-CycC inhibits fat accumulation by directly inactivating SREBP, a master transcription factor that controls the expression of lipogenic genes, which explains the abnormal fat accumulation in the cdk8 and cycC mutants. We find that CDK8 and CycC are required for EcR to bind to its target genes, serving as transcriptional cofactors for EcR-dependent gene expression. The expression of EcR target genes is compromised in cdk8 and cycC mutants and underpins the retarded pupariation phenotype. Starvation of feeding larvae precociously up-regulates CDK8 and EcR, prematurely down-regulates SREBP activity, and leads to early pupariation, whereas re-feeding starved larvae has opposite effects. Taken together, these results suggest that CDK8 and CycC play important roles in coordinating nutrition intake with fat metabolism by directly inhibiting SREBP-dependent gene expression and regulating developmental timing by activating EcR-dependent transcription in Drosophila.
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Affiliation(s)
- Xiao-Jun Xie
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Fu-Ning Hsu
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Xinsheng Gao
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Los Angeles, United States of America
| | - Jian-Quan Ni
- Gene Regulatory Laboratory, School of Medicine, Tsinghua University, Beijing, China
| | - Yue Xing
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Liying Huang
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Los Angeles, United States of America
| | - Hao-Ching Hsiao
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Haiyan Zheng
- Biological Mass Spectrometry Facility, Robert Wood Johnson Medical School and Rutgers, the State University of New Jersey, Frelinghuysen Road, Piscataway, New Jersey, United States of America
| | - Chenguang Wang
- Key Laboratory of Tianjin Radiation and Molecular Nuclear Medicine; Institute of Radiation Medicine, Peking Union Medical College & Chinese Academy of Medical Sciences, Tianjin, China
| | - Yani Zheng
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Alus M. Xiaoli
- Department of Medicine, Division of Endocrinology, Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Fajun Yang
- Department of Medicine, Division of Endocrinology, Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Sarah E. Bondos
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
- Department of Biosciences, Rice University, Houston, Texas, United States of America
| | - Jun-Yuan Ji
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, Texas, United States of America
- * E-mail:
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10
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Gautam NK, Verma P, Tapadia MG. Ecdysone regulates morphogenesis and function of Malpighian tubules in Drosophila melanogaster through EcR-B2 isoform. Dev Biol 2014; 398:163-76. [PMID: 25476260 DOI: 10.1016/j.ydbio.2014.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 10/20/2014] [Accepted: 11/11/2014] [Indexed: 10/24/2022]
Abstract
Malpighian tubules are the osmoregulatory and detoxifying organs of Drosophila and its proper development is critical for the survival of the organism. They are made up of two major cell types, the ectodermal principal cells and mesodermal stellate cells. The principal and stellate cells are structurally and physiologically distinct from each other, but coordinate together for production of isotonic fluid. Proper integration of these cells during the course of development is an important pre-requisite for the proper functioning of the tubules. We have conclusively determined an essential role of ecdysone hormone in the development and function of Malpighian tubules. Disruption of ecdysone signaling interferes with the organization of principal and stellate cells resulting in malformed tubules and early larval lethality. Abnormalities include reduction in the number of cells and the clustering of cells rather than their arrangement in characteristic wild type pattern. Organization of F-actin and β-tubulin also show aberrant distribution pattern. Malformed tubules show reduced uric acid deposition and altered expression of Na(+)/K(+)-ATPase pump. B2 isoform of ecdysone receptor is critical for the development of Malpighian tubules and is expressed from early stages of its development.
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Affiliation(s)
- Naveen Kumar Gautam
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005,Uttar Pradesh, India; Molecular and Human Genetics Laboratory, Department of Zoology, University of Lucknow, Lucknow 226007, Uttar Pradesh, India
| | - Puja Verma
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005,Uttar Pradesh, India
| | - Madhu G Tapadia
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005,Uttar Pradesh, India.
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11
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Musille PM, Kohn JA, Ortlund EA. Phospholipid--driven gene regulation. FEBS Lett 2013; 587:1238-46. [PMID: 23333623 DOI: 10.1016/j.febslet.2013.01.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 01/03/2013] [Accepted: 01/07/2013] [Indexed: 12/15/2022]
Abstract
Phospholipids (PLs), well known for their fundamental role in cellular structure, play critical signaling roles via their derivatives and cleavage products acting as second messengers in signaling cascades. Recent work has shown that intact PLs act as signaling molecules in their own right by modulating the activity of nuclear hormone transcription factors responsible for tuning genes involved in metabolism, lipid flux, steroid synthesis and inflammation. As such, PLs have been classified as novel hormones. This review highlights recent work in PL-driven gene regulation with a focus on the unique structural features of phospholipid-sensing transcription factors and what sets them apart from well known soluble phospholipid transporters.
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Affiliation(s)
- Paul M Musille
- Department of Biochemistry, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
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12
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Ou Q, King-Jones K. What goes up must come down: transcription factors have their say in making ecdysone pulses. Curr Top Dev Biol 2013; 103:35-71. [PMID: 23347515 DOI: 10.1016/b978-0-12-385979-2.00002-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Insect metamorphosis is one of the most fascinating biological processes in the animal kingdom. The dramatic transition from an immature juvenile to a reproductive adult is under the control of the steroid hormone ecdysone, also known as the insect molting hormone. During Drosophila development, periodic pulses of ecdysone are released from the prothoracic glands, upon which the hormone is rapidly converted in peripheral tissues to its biologically active form, 20-hydroxyecdysone. Each hormone pulse has a unique profile and causes different developmental events, but we only have a rudimentary understanding of how the timing, amplitude, and duration of a given pulse are controlled. A key component involved in the timing of ecdysone pulses is PTTH, a brain-derived neuropeptide. PTTH stimulates ecdysone production through a Ras/Raf/ERK signaling cascade; however, comparatively little is known about the downstream targets of this pathway. In recent years, it has become apparent that transcriptional regulation plays a critical role in regulating the synthesis of ecdysone, but only one transcription factor has a well-defined link to PTTH. Interestingly, many of the ecdysteroidogenic transcription factors were originally characterized as primary response genes in the ecdysone signaling cascade that elicits the biological responses to the hormone in target tissues. To review these developments, we will first provide an overview of the transcription factors that act in the Drosophila ecdysone regulatory hierarchy. We will then discuss the roles of these transcriptional regulators in controlling ecdysone synthesis. In the last section, we will briefly outline transcription factors that likely have roles in regulating ecdysone synthesis but have not been formally identified as downstream effectors of ecdysone.
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Affiliation(s)
- Qiuxiang Ou
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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13
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Carbonell A, Mazo A, Serras F, Corominas M. Ash2 acts as an ecdysone receptor coactivator by stabilizing the histone methyltransferase Trr. Mol Biol Cell 2012. [PMID: 23197473 PMCID: PMC3565548 DOI: 10.1091/mbc.e12-04-0267] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The molting hormone ecdysone triggers chromatin changes via histone modifications that are important for gene regulation. On hormone activation, the ecdysone receptor (EcR) binds to the SET domain-containing histone H3 methyltransferase trithorax-related protein (Trr). Methylation of histone H3 at lysine 4 (H3K4me), which is associated with transcriptional activation, requires several cofactors, including Ash2. We find that ash2 mutants have severe defects in pupariation and metamorphosis due to a lack of activation of ecdysone-responsive genes. This transcriptional defect is caused by the absence of the H3K4me3 marks set by Trr in these genes. We present evidence that Ash2 interacts with Trr and is required for its stabilization. Thus we propose that Ash2 functions together with Trr as an ecdysone receptor coactivator.
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Affiliation(s)
- Albert Carbonell
- Departament de Genètica and Institut de Biomedicina, Universitat de Barcelona, 08028 Barcelona, Spain
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14
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Nagy L, Szanto A, Szatmari I, Széles L. Nuclear hormone receptors enable macrophages and dendritic cells to sense their lipid environment and shape their immune response. Physiol Rev 2012; 92:739-89. [PMID: 22535896 DOI: 10.1152/physrev.00004.2011] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A key issue in the immune system is to generate specific cell types, often with opposing activities. The mechanisms of differentiation and subtype specification of immune cells such as macrophages and dendritic cells are critical to understand the regulatory principles and logic of the immune system. In addition to cytokines and pathogens, it is increasingly appreciated that lipid signaling also has a key role in differentiation and subtype specification. In this review we explore how intracellular lipid signaling via a set of transcription factors regulates cellular differentiation, subtype specification, and immune as well as metabolic homeostasis. We introduce macrophages and dendritic cells and then we focus on a group of transcription factors, nuclear receptors, which regulate gene expression upon receiving lipid signals. The receptors we cover are the ones with a recognized physiological function in these cell types and ones which heterodimerize with the retinoid X receptor. These are as follows: the receptor for a metabolite of vitamin A, retinoic acid: retinoic acid receptor (RAR), the vitamin D receptor (VDR), the fatty acid receptor: peroxisome proliferator-activated receptor γ (PPARγ), the oxysterol receptor liver X receptor (LXR), and their obligate heterodimeric partner, the retinoid X receptor (RXR). We discuss how they can get activated and how ligand is generated and eliminated in these cell types. We also explore how activation of a particular target gene contributes to biological functions and how the regulation of individual target genes adds up to the coordination of gene networks. It appears that RXR heterodimeric nuclear receptors provide these cells with a coordinated and interrelated network of transcriptional regulators for interpreting the lipid milieu and the metabolic changes to bring about gene expression changes leading to subtype and functional specification. We also show that these networks are implicated in various immune diseases and are amenable to therapeutic exploitation.
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Affiliation(s)
- Laszlo Nagy
- Department of Biochemistry and Molecular Biology, University of Debrecen, Medical and Health Science Center, Egyetem tér 1, Debrecen, Hungary.
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15
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Dawson MI, Xia Z. The retinoid X receptors and their ligands. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:21-56. [PMID: 22020178 DOI: 10.1016/j.bbalip.2011.09.014] [Citation(s) in RCA: 253] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 08/23/2011] [Accepted: 09/23/2011] [Indexed: 12/12/2022]
Abstract
This chapter presents an overview of the current status of studies on the structural and molecular biology of the retinoid X receptor subtypes α, β, and γ (RXRs, NR2B1-3), their nuclear and cytoplasmic functions, post-transcriptional processing, and recently reported ligands. Points of interest are the different changes in the ligand-binding pocket induced by variously shaped agonists, the communication of the ligand-bound pocket with the coactivator binding surface and the heterodimerization interface, and recently identified ligands that are natural products, those that function as environmental toxins or drugs that had been originally designed to interact with other targets, as well as those that were deliberately designed as RXR-selective transcriptional agonists, synergists, or antagonists. Of these synthetic ligands, the general trend in design appears to be away from fully aromatic rigid structures to those containing partial elements of the flexible tetraene side chain of 9-cis-retinoic acid. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).
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Affiliation(s)
- Marcia I Dawson
- Cancer Center, Sanford-Burn Medical Research Institute, 10901 North Torrey Pines Rd., La Jolla, CA 93207, USA.
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16
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Schauer S, Callender J, Henrich VC, Spindler-Barth M. The N-terminus of ecdysteroid receptor isoforms and ultraspiracle interacts with different ecdysteroid response elements in a sequence specific manner to modulate transcriptional activity. J Steroid Biochem Mol Biol 2011; 124:84-92. [PMID: 21316451 DOI: 10.1016/j.jsbmb.2011.01.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 01/26/2011] [Accepted: 01/27/2011] [Indexed: 12/23/2022]
Abstract
The functional insect ecdysteroid receptor is comprised of two nuclear receptors, the ecdysteroid receptor (EcR) and the RXR homologue, ultraspiracle (USP), which form a heterodimer. The dimer recognizes various hormone response elements and the effect of these elements on transcriptional activity of EcR isoforms was determined in vertebrate cells transfected with EcR and USP. Only constitutive activity mediated by the core response elements was preserved after elimination of nonspecific binding sites on the DNA of the vector. The constitutive transcriptional activity was regulated in a complex manner by the N-termini of both EcR and USP, the DBD of USP and the type and number of hormone response elements (HRE). Cooperative effects at oligomeric response elements particularly DR1 depended on the type of ecdysteroid response element and the N-termini of EcR and USP. The DBD of USP abolishes or attenuates synergistic effects. The data show that in the absence of hormone, transcriptional activity is regulated in a complex manner that offers additional possibilities for ecdysteroid receptor mediated gene regulation during development.
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Affiliation(s)
- Sebastian Schauer
- Institute of General Zoology and Endocrinology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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17
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Zheng WW, Yang DT, Wang JX, Song QS, Gilbert LI, Zhao XF. Hsc70 binds to ultraspiracle resulting in the upregulation of 20-hydroxyecdsone-responsive genes in Helicoverpa armigera. Mol Cell Endocrinol 2010; 315:282-91. [PMID: 19897013 DOI: 10.1016/j.mce.2009.10.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Revised: 10/29/2009] [Accepted: 10/30/2009] [Indexed: 10/20/2022]
Abstract
To probe the specific functions of the chaperone protein Hsc70 in 20-hydroxyecdysone signaling, we report on the roles of the Hsc70 from Helicoverpa armigera. RT-PCR analysis revealed that the genes for HaEcRB1 and HaUSP1 were upregulated in 5th molting and metamorphic molting larvae, whereas HaHsc70 maintained a constitutive expression level throughout larval development. Silencing HaEcRB1, HaUSP1 or HaHsc70 by RNAi inhibited the expression of a set of 20E-responsive genes. Immunocytochemical assay demonstrated that HaHsc70 is located predominantly in the cytoplasm of unstimulated cells and partially translocated to the nucleus after stimulation by 20E. Knockdown of HaHsc70 by RNAi decreased the amount of both HaEcRB1 and HaUSP1 in the nucleus. HaHsc70 was capable of binding to HaUSP1 in pull-down assays. These data suggest that Hsc70 participates in the 20E signal transduction pathway via binding to USP1 and mediating the expression of EcRB1, USP1 and then a set of 20E-responsive genes.
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Affiliation(s)
- Wei-Wei Zheng
- School of Life Sciences, the Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, Shandong University, Shanda Road 27, Jinan 250100, Shandong, China
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18
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Abstract
The molting process in arthropods is regulated by steroid hormones acting via nuclear receptor proteins. The most common molting hormone is the ecdysteroid, 20-hydroxyecdysone. The receptors of 20-hydroxyecdysone have also been identified in many arthropod species, and the amino acid sequences determined. The functional molting hormone receptors consist of two members of the nuclear receptor superfamily, namely the ecdysone receptor and the ultraspiracle, although the ecdysone receptor may be functional, in some instances, without the ultraspiracle. Generally, the ecdysone receptor/ultraspiracle heterodimer binds to a number of ecdysone response elements, sequence motifs that reside in the promoter of various ecdysteroid-responsive genes. In the ensuing transcriptional induction, the ecdysone receptor/ultraspiracle complex binds to 20-hydroxyecdysone or to a cognate ligand that, in turn, leads to the release of a corepressor and the recruitment of coactivators. 3D structures of the ligand-binding domains of the ecdysone receptor and the ultraspiracle have been solved for a few insect species. Ecdysone agonists bind to ecdysone receptors specifically, and ligand-ecdysone receptor binding is enhanced in the presence of the ultraspiracle in insects. The basic mode of ecdysteroid receptor action is highly conserved, but substantial functional differences exist among the receptors of individual species. Even though the transcriptional effects are apparently similar for ecdysteroids and nonsteroidal compounds such as diacylhydrazines, the binding shapes are different between them. The compounds having the strongest binding affinity to receptors ordinarily have strong molting hormone activity. The ability of the ecdysone receptor/ultraspiracle complex to manifest the effects of small lipophilic agonists has led to their use as gene switches for medical and agricultural applications.
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Affiliation(s)
- Yoshiaki Nakagawa
- Division of Applied Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-Ku, Kyoto 606-8502, Japan.
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19
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Bitra K, Palli SR. Interaction of proteins involved in ecdysone and juvenile hormone signal transduction. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2009; 70:90-105. [PMID: 18980211 DOI: 10.1002/arch.20281] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Ecdysteroids and juvenile hormones (JH) regulate a variety of developmental, physiological, behavioral, and metabolic processes. Ecdysteroids function through a heterodimeric complex of two nuclear receptors, ecdysone receptor (EcR) and ultraspiracle (USP). An 85 kDa protein identified in Drosophila melanogaster methoprene-tolerant (Met) mutant binds to JH III with high affinity, and the mutant flies are resistant to juvenile hormone analog (JHA), methoprene. Reporter assays using the yeast two-hybrid system were performed in order to study the molecular interactions between EcR, USP and Met. As expected, EcR fused to the B42 activation domain and USP fused to the LexA DNA binding domain interacted with each other and supported induction of the reporter gene in the presence of stable ecdysteroid analog, RG-102240 or steroids, muristerone A and ponasterone A. The USP:USP homodimers supported expression of the reporter gene in the absence of ligand, and there was no significant increase in the reporter activity after addition of a JHA, methoprene. Similarly, Met:Met homodimers as well as Met:EcR and Met:USP heterodimers induced reporter activity in the absence of ligand and addition of ecdysteroid or JH analogs did not increase the reporter activity regulated by either homodimers or heterodimers of Met protein. Two-hybrid assays in insect cells and in vitro pull-down assays confirmed the interaction of Met with EcR and USP. These data suggest that the proteins that are involved in signal transduction of ecdysteroids (EcR and USP) and juvenile hormones (Met) interact to mediate cross-talk between these two important hormones. Arch. Insect Biochem. Physiol. 2008. (c) 2008 Wiley-Liss, Inc.
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Affiliation(s)
- Kavita Bitra
- Department of Entomology, University of Kentucky, Lexington, KY 40506, USA
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20
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Cavaliere V, Bernardi F, Romani P, Duchi S, Gargiulo G. Building up theDrosophilaeggshell: First of all the eggshell genes must be transcribed. Dev Dyn 2008; 237:2061-72. [DOI: 10.1002/dvdy.21625] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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21
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Costantino BFB, Bricker DK, Alexandre K, Shen K, Merriam JR, Antoniewski C, Callender JL, Henrich VC, Presente A, Andres AJ. A novel ecdysone receptor mediates steroid-regulated developmental events during the mid-third instar of Drosophila. PLoS Genet 2008; 4:e1000102. [PMID: 18566664 PMCID: PMC2413497 DOI: 10.1371/journal.pgen.1000102] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 05/20/2008] [Indexed: 11/18/2022] Open
Abstract
The larval salivary gland of Drosophila melanogaster synthesizes and secretes glue glycoproteins that cement developing animals to a solid surface during metamorphosis. The steroid hormone 20-hydroxyecdysone (20E) is an essential signaling molecule that modulates most of the physiological functions of the larval gland. At the end of larval development, it is known that 20E--signaling through a nuclear receptor heterodimer consisting of EcR and USP--induces the early and late puffing cascade of the polytene chromosomes and causes the exocytosis of stored glue granules into the lumen of the gland. It has also been reported that an earlier pulse of hormone induces the temporally and spatially specific transcriptional activation of the glue genes; however, the receptor responsible for triggering this response has not been characterized. Here we show that the coordinated expression of the glue genes midway through the third instar is mediated by 20E acting to induce genes of the Broad Complex (BRC) through a receptor that is not an EcR/USP heterodimer. This result is novel because it demonstrates for the first time that at least some 20E-mediated, mid-larval, developmental responses are controlled by an uncharacterized receptor that does not contain an RXR-like component.
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Affiliation(s)
- Benjamin F. B. Costantino
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, United States of America
| | - Daniel K. Bricker
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, United States of America
| | - Kelly Alexandre
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, United States of America
| | - Kate Shen
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, United States of America
| | - John R. Merriam
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, California, United States of America
| | | | - Jenna L. Callender
- Center for Biotechnology, Genomics, and Health Research, University of North Carolina Greensboro, Greensboro, North Carolina, United States of America
| | - Vincent C. Henrich
- Center for Biotechnology, Genomics, and Health Research, University of North Carolina Greensboro, Greensboro, North Carolina, United States of America
| | - Asaf Presente
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, United States of America
| | - Andrew J. Andres
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, United States of America
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22
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Nieva C, Spindler-Barth M, Spindler KD. Impact of heterodimerization on intracellular localization of the ecdysteroid receptor (EcR). ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2008; 68:40-48. [PMID: 18271015 DOI: 10.1002/arch.20234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Initially, nuclear import of the ecdysteroid receptor (EcR) in vertebrate cells (CHO-K1 and COS-7) does not afford a heterodimerization partner. Later on, EcR is retained in the nucleus only in the presence of a heterodimerization partner. Ultraspiracle (Usp) is more efficient compared to its vertebrate orthologue RXR and leads to an exclusively nuclear localization of EcR even in the absence of ligand. The DNA binding domain of the heterodimerization partner is important for retainment of EcR in the nucleus as shown by Usp4 (Usp(R130C)), which has lost its DNA binding capability. The C-terminal end of Usp (Usp(Delta205-508)) encompassing the C-terminal part of the D-domain and the E- and F-domains are essential for retainment of EcR in the nucleus. Nuclear localization is further influenced by cell-specific factors, since hormone and heterodimerization stabilizes the EcR protein in a cell-specific way.
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Affiliation(s)
- Claudia Nieva
- Institute of General Zoology and Endocrinology, University of Ulm, Ulm, Germany
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23
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Horigane M, Ogihara K, Nakajima Y, Taylor D. Isolation and expression of the retinoid X receptor from last instar nymphs and adult females of the soft tick Ornithodoros moubata (Acari: Argasidae). Gen Comp Endocrinol 2008; 156:298-311. [PMID: 18342313 DOI: 10.1016/j.ygcen.2008.01.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 12/20/2007] [Accepted: 01/29/2008] [Indexed: 11/30/2022]
Abstract
Retinoid X receptors (RXR) exist broadly from invertebrates to vertebrates, and play essential roles in physiological processes of these organisms. In arthropods, RXRs form a complex with the ecdysteroid receptor (EcR) and ecdysteroids to mediate the regulation of ecdysis and reproduction. Compared to EcR, RXR and its homologue ultraspiracle (USP) are much less well understood. Therefore, we identified RXR of the soft tick Ornithodoros moubata (OmRXR) and used real-time PCR to examine the expression of OmRXR. This is the first report of RXR from a soft tick. OmRXR showed higher homology to hard tick, crustacean and vertebrate RXRs than insect RXRs and USPs. OmRXR expression was observed during molting in the last instar nymphs coinciding with EcR expression and increases in ecdysteroid titers. Tick vitellogenesis normally occurs soon after engorgement and OmRXR expression coinciding with EcR expression and ecdysteroid titers in engorged females occurred before vitellogenin (Vg) synthesis and egg maturation. The ecdysteroid/EcR/RXR complex appears to be important in the regulation of molting and vitellogenesis of soft ticks.
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Affiliation(s)
- Mari Horigane
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
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24
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Dhadialla TS, Le D, Palli SR, Raikhel A, Carlson GR. A photoaffinity, non-steroidal, ecdysone agonist, bisacylhydrazine compound, RH-131039: characterization of binding and functional activity. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2007; 37:865-75. [PMID: 17628285 DOI: 10.1016/j.ibmb.2007.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 05/15/2007] [Accepted: 05/16/2007] [Indexed: 05/16/2023]
Abstract
In this paper we describe the synthesis, ligand-binding and functional activity characteristics of the photoaffinity, non-steroidal, ecdysone agonist, bisacylhydrazine compound, 3-benzoyl-benzoic acid N-tert-butyl-N'-(2-ethyl-3-methoxy-benzoyl)-hydrazide (RH-131039). Tritiated RH-131039 is the first non-steroidal photoaffinity compound that was shown to bind specifically to ecdysone receptors (EcRs) from insects belonging to the orders Diptera and Lepidoptera. The spruce budworm (Choristoneura fumiferana) ecdysone receptor (CfEcR) bound with high affinity (K(d)=2.23+/-0.27 nM) to this compound. When irradiated with UV light (lambda=350 nm) under equilibrium ligand-binding conditions, RH-131039 attached specifically and covalently to the CfEcR ligand-binding domain (LBD). RH-131039 also bound to cloned ecdysone receptor proteins from three dipteran insects, Drosophila melanogaster, Aedes aegypti and Chironomous tentans. This paper also describes and invokes caution in interpretation of ligand-binding results obtained using crude cellular extracts containing target receptors, as illustrated with the use of Drosophila Kc cells that have functional EcR and L57 cells (derivatives of Kc cells in which EcR-B isoforms have been knocked out by "parahomologous" recombination). Tritiated RH-131039 is a useful tool to dissect ligand-binding and functional differences for EcRs from different arthropod species.
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25
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Beatty J, Fauth T, Callender JL, Spindler-Barth M, Henrich VC. Analysis of transcriptional activity mediated by Drosophila melanogaster ecdysone receptor isoforms in a heterologous cell culture system. INSECT MOLECULAR BIOLOGY 2006; 15:785-95. [PMID: 17201771 DOI: 10.1111/j.1365-2583.2006.00683.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Ecdysteroid regulation of gene transcription in Drosophila melanogaster and other insects is mediated by a heterodimer comprised of Ultraspiracle (USP) and one of three ecdysone receptor (EcR) isoforms (A, B1 and B2). This study revealed that the EcR/USP heterodimer displays isoform-specific capabilities. EcRB1 is normally induced with a form of USP that is missing its DNA-binding domain (DBD), although potentiation by juvenile hormone (JH) III is reduced. The EcRA and B2 isoforms, however, display almost no response to ecdysteroids with the DBD(-) USP. A mutation, K497E, in the shared ligand-binding domain of the EcR isoforms caused elevated EcRB2-specific affinity for a canonical ecdysone response element. The effects of directed modification and mutagenesis offer a strategy for developing hypotheses and considerations for studying in vivo function.
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Affiliation(s)
- J Beatty
- Center for Biotechnology, Genomics and Health Research, University of North Carolina-Greensboro, Greensboro, NC 27402-6170, USA
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26
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Sun X, Song Q. PKC-mediated USP phosphorylation is required for 20E-induced gene expression in the salivary glands of Drosophila melanogaster. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2006; 62:116-27. [PMID: 16783823 DOI: 10.1002/arch.20130] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Ecdysone receptor (EcR) and its heterodimer, ultraspiracle protein (USP), are ligand-dependent transcriptional factors that mediate the action of molting hormone 20-hydroxyecdysone. The activities of transcriptional factors are subjected to regulation not only by transcriptional/translational mechanisms, but also by posttranslational mechanisms such as phosphorylation. Protein kinase consensus recognition sequence analysis of Drosophila EcR and USP reveals multiple phosphorylation sites for protein kinase C (PKC) and casein kinase II (CKII) on EcR and USP sequence. By using specific protein kinase inhibitors, we have shown that PKC, not CKII, is responsible for USP phosphorylation. Inhibition of PKC activity by protein kinase inhibitors blocked USP phosphorylation, resulting in inhibition of 20E-induced gene expression at both transcriptional and translational levels. The composite data suggest that PKC-mediated USP phosphorylation is required for 20E-induced gene expression in the salivary glands of Drosophila melanogaster.
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Affiliation(s)
- Xiaoping Sun
- Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA
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27
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Martín D, Maestro O, Cruz J, Mané-Padrós D, Bellés X. RNAi studies reveal a conserved role for RXR in molting in the cockroach Blattella germanica. JOURNAL OF INSECT PHYSIOLOGY 2006; 52:410-6. [PMID: 16427073 DOI: 10.1016/j.jinsphys.2005.12.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 11/28/2005] [Accepted: 12/05/2005] [Indexed: 05/06/2023]
Abstract
Ecdysteroids play a major role during developmental growth in insects. The more active form of these hormones, 20-hydroxyecdysone (20E), acts upon binding to its heterodimeric receptor, formed by the two nuclear receptors, EcR and RXR/USP. Functional characterization of USP has been exclusively conducted on the holometabolous insect Drosophila melanogaster. However, it has been impossible to extend such analysis to primitive-hemimetabolous insects since species of this group are not amenable to genetic analysis. The development of methodologies based on gene silencing using RNA interference (RNAi) after treatment with double-stranded RNA (dsRNA) in vivo has resolved such limitations. In this paper, we show that injection of dsRNA into the haemocoel of nymphs and adults of the cockroach Blattella germanica can be used to silence gene function in vivo. In our initial attempt to test RNAi techniques, we halted the expression of the adult-specific vitellogenin gene. We then used the same technique to silence the expression of the B. germanica RXR/USP (BgRXR) gene in vivo during the last nymphal instar. BgRXR knockdown nymphs progressed through the instar correctly but they arrested development at the end of the stage and were unable to molt into adults. The results described herein suggest that RXR/USP function, in relation to molting, is conserved across the insect Class.
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Affiliation(s)
- David Martín
- Departament de Fisiologia i Biodiversitat Molecular, Institut de Biologia Molecular de Barcelona (CID, CSIC), Jordi Girona 18, 08034 Barcelona, Spain.
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28
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Palli SR, Kapitskaya MZ, Potter DW. The influence of heterodimer partner ultraspiracle/retinoid X receptor on the function of ecdysone receptor. FEBS J 2005; 272:5979-90. [PMID: 16302963 DOI: 10.1111/j.1742-4658.2005.05003.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A pair of nuclear receptors, ecdysone receptor (EcR) and ultraspiracle (USP), heterodimerize and transduce ecdysteroid signals. The EcR and its nonsteroidal ligands are being developed for regulation of transgene expression in humans, animals and plants. In mammalian cells, EcR:USP heterodimers can function in the absence of ligand, but EcR/retinoid X receptor (EcR:RXR) heterodimers require the presence of ligand for activation. The heterodimer partner of EcR can influence ligand sensitivity of EcR so that the EcR/Locusta migratoria RXR (EcR:LmRXR) heterodimers are activated at lower concentrations of ligand when compared with the concentrations of ligand required for the activation of EcR/Homo sapiens RXR (EcR:HsRXR) heterodimers. Analysis of chimeric RXRs containing regions of LmRXR and HsRXR and point mutants of HsRXR showed that the amino acid residues present in helix 9 and in the two loops on either end of helix 9 are responsible for improved activity of LmRXR. The EcR:Lm-HsRXR chimera heterodimer induced reporter genes with nanomolar concentration of ligand compared with the micromolar concentration of ligand required for activating the EcR:HsRXR heterodimer. The EcR:Lm-HsRXR chimera heterodimer, but not the EcR:HsRXR heterodimer, supported ligand-dependent induction of reporter gene in a C57BL/6 mouse model.
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Affiliation(s)
- Subba R Palli
- Department of Entomology, University of Kentucky, Lexington, KY 40546, USA.
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29
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Szanto A, Narkar V, Shen Q, Uray IP, Davies PJA, Nagy L. Retinoid X receptors: X-ploring their (patho)physiological functions. Cell Death Differ 2005; 11 Suppl 2:S126-43. [PMID: 15608692 DOI: 10.1038/sj.cdd.4401533] [Citation(s) in RCA: 202] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Retinoid X receptor (RXR) belongs to a family of ligand-activated transcription factors that regulate many aspects of metazoan life. A class of nuclear receptors requires RXR as heterodimerization partner for their function. This places RXR in the crossroad of multiple distinct biological pathways. This and the fact that the debate on the endogenous ligand requirement for RXR is not yet settled make RXR still an enigmatic transcription factor. Here, we review some of the biology of RXR. We place RXR into the evolution of nuclear receptors, review structural details and ligands of the receptor. Then processes regulated by RXR are discussed focusing on the developmental roles deduced from studies on knockout animals and metabolic roles in diseases such as diabetes and atherosclerosis deduced from pharmacological studies. Finally, aspects of RXR's involvement in myeloid differentiation and apoptosis are summarized along with issues on RXR's suitability as a therapeutic target.
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Affiliation(s)
- A Szanto
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, University of Debrecen, Nagyerdei krt. 98, Debrecen H-4012, Hungary
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30
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Carmichael JA, Lawrence MC, Graham LD, Pilling PA, Epa VC, Noyce L, Lovrecz G, Winkler DA, Pawlak-Skrzecz A, Eaton RE, Hannan GN, Hill RJ. The X-ray structure of a hemipteran ecdysone receptor ligand-binding domain: comparison with a lepidopteran ecdysone receptor ligand-binding domain and implications for insecticide design. J Biol Chem 2005; 280:22258-69. [PMID: 15809296 DOI: 10.1074/jbc.m500661200] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ecdysone receptor is a hormone-dependent transcription factor that plays a central role in regulating the expression of vast networks of genes during development and reproduction in the phylum Arthropoda. The functional receptor is a heterodimer of the two nuclear receptor proteins ecdysone receptor (EcR) and ultraspiracle protein. The receptor is the target of the environmentally friendly bisacylhydrazine insecticides, which are effective against Lepidoptera but not against Hemiptera or several other insect orders. Here we present evidence indicating that much of the selectivity of the bisacylhydrazine insecticides can be studied at the level of their binding to purified ecdysone receptor ligand-binding domain (LBD) heterodimers. We report the crystal structure of the ecdysone receptor LBD heterodimer of the hemipteran Bemisia tabaci (Bt, sweet potato whitefly) in complex with the ecdysone analogue ponasterone A. Although comparison with the corresponding known LBD structure from the lepidopteran Heliothis virescens (Hv) ecdysone receptor revealed the overall mode of ponasterone A binding to be very similar in the two cases, we observed that the BtEcR ecdysteroid-binding pocket is structured differently to that of HvEcR in those parts that are not in contact with ponasterone A. We suggest that these differences in the ligand-binding pocket may provide a molecular basis for the taxonomic order selectivity of bisacylhydrazine insecticides.
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MESH Headings
- Amino Acid Sequence
- Animals
- Binding, Competitive
- Cloning, Molecular
- Crystallography, X-Ray
- Dimerization
- Dose-Response Relationship, Drug
- Gene Expression Regulation, Developmental
- Hydrazines/chemistry
- Hydrazines/pharmacology
- Insecta
- Insecticides/pharmacology
- Ligands
- Models, Molecular
- Molecular Sequence Data
- Protein Binding
- Protein Conformation
- Protein Structure, Tertiary
- Receptors, Steroid/chemistry
- Receptors, Steroid/metabolism
- Sequence Homology, Amino Acid
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Affiliation(s)
- Jennifer A Carmichael
- CSIRO Health Sciences and Nutrition, 343 Royal Parade, Parkville, Victoria 3052, Australia
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31
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Siaussat D, Bozzolan F, Queguiner I, Porcheron P, Debernard S. Cell cycle profiles of EcR, USP, HR3 and B cyclin mRNAs associated to 20E-induced G2 arrest of Plodia interpunctella imaginal wing cells. INSECT MOLECULAR BIOLOGY 2005; 14:151-161. [PMID: 15796748 DOI: 10.1111/j.1365-2583.2004.00540.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Using the IAL-PID2 cell line established from pupally committed imaginal wing discs of Plodia interpunctella, we have investigated the dynamics of cellular and molecular events involved in the G2/M arrest. We have first cloned a cDNA sequence named PIUSP-2 that likely encodes a homologue of the Ultraspiracle-2 isoform of Manduca sexta. When the IAL-PID2 cells were exposed to a 8 h 20E treatment applied at different times of the cell cycle, an optimal period of sensitivity of cells to 20E, in inducing G2 arrest, was determined at the S/G2 transition. Using cDNA probes specifically designed from Plodia B cyclin (PcycB), ecdysone receptor B1-isoform (PIEcR-B1) and HR3 transcription factor (PHR3), we provide evidence that the 20E-induced G2 arrest was correlated to a high induction of PHR3, PIEcR-B1, PIUSP-2 mRNAs at the S/G2 transition and a decrease in PcycB mRNA level at the end of G2 phase.
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Affiliation(s)
- D Siaussat
- Laboratoire de Physiologie Cellulaire des Invertébrés, Université Pierre et Marie Curie, Paris, France.
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32
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Nieva C, Gwóźdź T, Dutko-Gwóźdź J, Wiedenmann J, Spindler-Barth M, Wieczorek E, Dobrucki J, Duś D, Henrich V, Ozyhar A, Spindler KD. Ultraspiracle promotes the nuclear localization of ecdysteroid receptor in mammalian cells. Biol Chem 2005; 386:463-70. [PMID: 15927890 DOI: 10.1515/bc.2005.055] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The heterodimer consisting of ecdysteroid receptor (EcR) and ultraspiracle (USP), both of which are members of the nuclear receptor superfamily, is considered to be the functional ecdysteroid receptor. Here we analyzed the subcellular distribution of EcR and USP fused to fluorescent proteins. The experiments were carried out in mammalian COS-7, CHO-K1 and HeLa cells to facilitate investigation of the subcellular trafficking of EcR and USP in the absence of endogenous expression of these two receptors. The distribution of USP tagged with a yellow fluorescent protein (YFP-USP) was almost exclusively nuclear in all cell types analyzed. The nuclear localization remained constant for at least 1 day after the first visible signs of expression. In contrast, the intracellular distribution of EcR tagged with a yellow fluorescent protein (YFP-EcR) varied and was dependent on time and cell type, although YFP-EcR alone was also able to partially translocate into the nuclear compartment. Coexpression of YFP-EcR with USP tagged with a cyan fluorescent protein (CFP-USP) resulted in exclusively nuclear localization of both proteins in all cell types analyzed. The USP-induced nuclear localization of YFP-EcR was stable for at least 20 hours. These experiments suggest that USP has a profound effect on the subcellular distribution of EcR.
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Affiliation(s)
- Claudia Nieva
- Department of General Zoology and Endocrinology, University of Ulm, D-89069 Ulm, Germany
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33
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Berger EM, Dubrovsky EB. Juvenile hormone molecular actions and interactions during development of Drosophila melanogaster. VITAMINS AND HORMONES 2005; 73:175-215. [PMID: 16399411 DOI: 10.1016/s0083-6729(05)73006-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Edward M Berger
- Department Of Biology, Dartmouth College, Hanover, New Hampshire 03755, USA
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34
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Bergman T, Henrich VC, Schlattner U, Lezzi M. Ligand control of interaction in vivo between ecdysteroid receptor and ultraspiracle ligand-binding domain. Biochem J 2004; 378:779-84. [PMID: 14594447 PMCID: PMC1223994 DOI: 10.1042/bj20031302] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Revised: 10/10/2003] [Accepted: 10/31/2003] [Indexed: 01/10/2023]
Abstract
Ecdysteroids (Ecs) enhance the formation of Ec receptor-ultraspiracle protein (EcR-USP) heterodimers which regulate gene transcription. To study EcR-USP heterodimerization, fusion proteins were constructed from the LBDs (ligand-binding domains) of Drosophila EcR or USP and the activation or DNA-binding region of GAL4 respectively. Reporter gene ( lacZ ) activation was fully dependent on the co-expression of the two fusion proteins and thus constitutes a reliable measure for the interaction in vivo between the two LBDs in the yeast cell. To identify structures involved in heterodimerization, a total of 27 point mutations were generated in the EcR and USP LBDs at selected sites. Heterodimerization and its inducibility by ligand were mainly affected by mutations in the dimerization interface and in the ligand-binding pocket of EcR respectively. However, also mutations not located in these structures or even in the LBD of USP influenced ligand-dependent heterodimerization. Together with previously reported ligand-binding studies, the existence of such local, intra- and inter-molecular mutation effects suggest that ligand-induced dimerization results from a synergistic interaction between ligand-binding and heterodimerization functions in EcR LBD, and that it depends on global features of the LBDs of EcR and USP and on their mutual surface compatibility.
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Affiliation(s)
- Thomas Bergman
- Institute for Cell Biology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
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35
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Wilson TG. The molecular site of action of juvenile hormone and juvenile hormone insecticides during metamorphosis: how these compounds kill insects. JOURNAL OF INSECT PHYSIOLOGY 2004; 50:111-121. [PMID: 15019512 DOI: 10.1016/j.jinsphys.2003.12.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2003] [Revised: 12/04/2003] [Accepted: 12/05/2003] [Indexed: 05/24/2023]
Abstract
Studies in a variety of insects during the past four decades has deepened our understanding of juvenile hormone (JH) physiology, but how this hormone works at the molecular level remains elusive. Similarly, the mechanism of toxicity of JH analogue insecticides is still in question. There is much evidence from laboratory usage that JHAs act as JH agonists and generally show the highest toxicity when applied at the onset of metamorphosis. A physiological basis for the toxicity and morphogenetic effects has been suggested by recent work linking these effects with interference with the expression or action of certain genes, particularly the Broad-Complex (BR-C) transcription factor gene, that direct metamorphic change. Misexpressed BR-C then leads to improper expression of one or more downstream effector genes controlled by BR-C gene products, resulting in abnormal developmental and physiological changes that disrupt metamorphosis. Therefore, JH is a necessary molecule at certain times in insect development but becomes toxic when present during metamorphosis.
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Affiliation(s)
- Thomas G Wilson
- Department of Entomology, 400 Aronoff Laboratory, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA.
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36
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Mouillet JF, Henrich VC, Lezzi M, Vögtli M. Differential control of gene activity by isoforms A, B1 and B2 of theDrosophilaecdysone receptor. ACTA ACUST UNITED AC 2003. [DOI: 10.1046/j.1432-1327.2001.02051.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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37
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Song Q, Sun X, Jin XY. 20E-regulated USP expression and phosphorylation in Drosophila melanogaster. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2003; 33:1211-1218. [PMID: 14599493 DOI: 10.1016/j.ibmb.2003.06.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The developmental profiles of ultraspiracle protein (USP) in the tissues of Drosophila melanogaster were investigated using a USP specific monoclonal antibody (mAb) as a probe. Western blot analysis revealed four USP mAb reactive bands (p46, p48, p54 and p56), each with tissue- and stage-specific expression patterns. The p54 and p56 were expressed in nearly all larval and prepupal tissues tested with fluctuations in abundance. However, the p46 and p48 were detected exclusively in the midgut of prepupae and shown to be the proteolytic products of p54 and p56. A lambda protein phosphatase assay demonstrated that the p56 is the phosphorylated form of p54. The expression and phosphorylation of the p54 USP is regulated by 20E. Protein kinase consensus recognition sequence analysis revealed 10 putative phosphorylation sites in Drosophila USP, with seven sites for protein kinase C (PKC) and three sites for casein kinase II (CKII). The fact that seven out of 10 putative phosphorylation sites reside in the ligand- and DNA-binding domains suggests that phosphorylation may play important role in regulating USP function. Identification of the in vivo USP phosphorylation sites and signal transduction pathways that regulate the specific USP phosphorylation is currently underway.
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Affiliation(s)
- Q Song
- Department of Entomology, University of Missouri, 1-87 Agriculture Building, Columbia, MO 65211, USA.
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38
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Minakuchi C, Nakagawa Y, Kamimura M, Miyagawa H. Binding affinity of nonsteroidal ecdysone agonists against the ecdysone receptor complex determines the strength of their molting hormonal activity. ACTA ACUST UNITED AC 2003; 270:4095-104. [PMID: 14519121 DOI: 10.1046/j.1432-1033.2003.03801.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
N-tert-Butyl-N,N'-dibenzoylhydrazine and its analogs are nonsteroidal ecdysone agonists that exhibit insect molting hormonal and larvicidal activities. The interaction mode of those ecdysone agonists with the heterodimer of the ecdysone receptor and ultraspiracle has not been fully elucidated. We expressed the ecdysone receptor B1 and the ultraspiracle of the lepidopteran, Chilo suppressalis, using an in vitro transcription/translation system and confirmed, using gel-shift assays, that the proteins function as ecdysone receptors. We also analyzed their ligand-binding affinity. A potent ecdysteroid, ponasterone A, specifically bound to the ecdysone receptor with low affinity (KD = 55 nm), and the specific binding was dramatically increased (KD = 1.2 nm) in the presence of the ultraspiracle. For seven nonsteroidal ecdysone agonists and five ecdysteroids, the binding activity to the in vitro-translated ecdysone receptor-ultraspiracle complex was linearly correlated with the binding activity to the inherent receptor protein in the cell-free preparation of C. suppressalis integument. The binding to the ecdysone receptor-ultraspiracle complex for a series of compounds was highly correlated with their molting hormonal activity, indicating that the binding affinity of nonsteroidal ecdysone agonists to the ecdysone receptor-ultraspiracle complex primarily determines the strength of their molting hormonal activity.
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Affiliation(s)
- Chieka Minakuchi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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39
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Abstract
Autophagic programmed cell death occurs during the development of diverse animal groups, but the mechanisms that control this genetically regulated form of cell killing are poorly understood. Genetic studies of bulk protein degradation in yeast have provided important advances in our understanding of autophagy, and recent investigations of Drosophila autophagic cell death suggest that some of these mechanisms may be conserved. In Drosophila, several steroid-regulated genes that encode transcription regulators are required for autophagic cell death. These transcription regulators appear to activate a large number of genes that play a more direct role in cell killing, including genes that function in apoptosis such as caspases. While caspase function is required for autophagic cell death during Drosophila development, genes encoding proteins that are similar to the yeast autophagy regulators are also induced in dying salivary glands. Furthermore, numerous noncaspase proteases, cytoplasmic organizing factors, signaling molecules, and unknown factors are expressed in interesting patterns during autophagic cell death. This article reviews the current knowledge of the regulation of autophagic programmed cell death during development of Drosophila.
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Affiliation(s)
- E H Baehrecke
- Center for Biosystems Research, University of Maryland Biotechnology Institute, College Park, MD 20742, USA
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40
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Minakuchi C, Nakagawa Y, Kiuchi M, Seino A, Tomita S, Kamimura M. Molecular cloning and expression analysis of ultraspiracle (USP) from the rice stem borer Chilo suppressalis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2003; 33:41-49. [PMID: 12459199 DOI: 10.1016/s0965-1748(02)00165-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
cDNA for ultraspiracle (USP) from the lepidopteran rice stem borer Chilo suppressalis was cloned using PCR techniques. The deduced amino acid sequence of C. suppressalis USP (CsUSP) was very similar to those of other lepidopteran USPs, especially to the Manduca sexta USP-2 isoform. Northern hybridization analysis detected a 6.5-kb message in the epidermis, fat body, and midgut of wandering larvae. CsUSP mRNA expression in the epidermis varied little during the last larval instar. Gel mobility shift assays showed that in vitro translated C. suppressalis ecdysone receptor (CsEcR) and CsUSP proteins bound to the Pal1 or Drosophila melanogaster hsp27 ecdysone response element as a heterodimer. In a ligand-receptor binding assay, [(3)H]ponasterone A ([(3)H]PoA) did not bind to individual CsEcR or CsUSP protein, but bound strongly to the CsEcR/CsUSP complex. [(3)H]PoA binding to CsEcR/CsUSP complex was competed by 20-hydroxyecdysone and a non-steroidal ecdysteroid agonist, RH-5992, but not by cholesterol, indicating that compounds with molting hormone activity against C. suppressalis can bind specifically to the CsEcR/CsUSP complex.
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Affiliation(s)
- Chieka Minakuchi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, 606-8502, Kyoto, Japan
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41
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Xu Y, Fang F, Chu Y, Jones D, Jones G. Activation of transcription through the ligand-binding pocket of the orphan nuclear receptor ultraspiracle. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:6026-36. [PMID: 12473098 DOI: 10.1046/j.1432-1033.2002.03293.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The invertebrate nuclear receptor, ultraspiracle (USP), an ortholog of the vertebrate RXR, is typically modelled as an orphan receptor that functions without a ligand-binding activity. The identification of a ligand that can transcriptionally activate USP would provide heuristic leads to the structure of potentially high affinity activating compounds, with which to detect unknown regulatory pathways in which this nuclear receptor participates. We show here that the application of the sesquiterpenoid methyl epoxyfarnesoate (juvenile hormone III) to Sf9 cells induces transcription from a transfected heterologous core promoter, through a 5'-placed DR12 enhancer to which the receptor ultraspiracle (USP) binds. Isolated, recombinant USP from Drosophila melanogaster specifically binds methyl epoxyfarnesoate, whereupon the receptor homodimerizes and changes tertiary conformation, including the movement of the ligand-binding domain alpha-helix 12. Ligand-binding pocket point mutants of USP that do not bind methyl epoxyfarnesoate act as dominant negative suppressors of methyl epoxyfarnesoate-activation of the reporter promoter, and addition of wild-type USP rescues this activation. These data establish a paradigm in which the USP ligand-binding pocket can productively bind ligand with a functional outcome of enhanced promoter activity, the first such demonstration for an invertebrate orphan nuclear receptor. USP thus establishes the precedent that invertebrate orphan receptors are viable targets for development of agonists and antagonists with which to discern and manipulate transcriptional pathways dependent on USP or other orphan receptors. The demonstration here of these functional capacities of USP in a transcriptional activation pathway has significant implications for current paradigms of USP action that do not include for USP a ligand-binding activity.
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Affiliation(s)
- Yong Xu
- Molecular and Cellular Biology Section, Department of Biology, and Graduate Center for Toxicology, Chandler Medical Center, University of Kentucky Lexington, USA
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42
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Minakuchi C, Nakagawa Y, Kiuchi M, Tomita S, Kamimura M. Molecular cloning, expression analysis and functional confirmation of two ecdysone receptor isoforms from the rice stem borer Chilo suppressalis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2002; 32:999-1008. [PMID: 12213236 DOI: 10.1016/s0965-1748(02)00036-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
PCR techniques were used to clone and identify cDNAs for ecdysone receptor A and B1 (EcR-A and EcR-B1) isoforms from the rice stem borer, Chilo suppressalis. They differ only in the N-terminal A/B regions and show high sequence identities to other insects' EcRs. At the wandering stage, EcR-B1 mRNA was expressed more abundantly in the midgut than in the epidermis and fat body, whereas expression levels of EcR-A mRNA were similar in the three tissues. In the epidermis of the last instar larvae, the maximal mRNA expression of both EcR-A and EcR-B1 was observed from the wandering to prepupal stages prior to the peak of ecdysteroid titer in the hemolymph. In gel mobility shift assays, in vitro translated C. suppressalis EcR-B1 (CsEcR-B1) and Bombyx mori ultraspiracle (BmUSP) proteins bound to the Pal 1 and Drosophila melanogaster hsp27 ecdysone response element as a heterodimer. These results indicate that the cDNAs isolated here encode functional ecdysone receptors.
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Affiliation(s)
- C Minakuchi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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Lezzi M, Bergman T, Henrich VC, Vögtli M, Frömel C, Grebe M, Przibilla S, Spindler-Barth M. Ligand-induced heterodimerization between the ligand binding domains of the Drosophila ecdysteroid receptor and ultraspiracle. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:3237-45. [PMID: 12084064 DOI: 10.1046/j.1432-1033.2002.03001.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The insect ecdysteroid receptor consists of a heterodimer between EcR and the RXR-orthologue, USP. We addressed the question of whether this heterodimer, like all other RXR heterodimers, may be formed in the absence of ligand and whether ligand promotes dimerization. We found that C-terminal protein fragments that comprised the ligand binding, but not the DNA binding domain of EcR and USP and which were equipped with the activation or DNA binding region of GAL4, respectively, exhibit a weak ability to interact spontaneously with each other. Moreover, the heterodimer formation is greatly enhanced upon administration of active ecdysteroids in a dose-dependent manner. This was shown in vivo by a yeast two-hybrid system and in vitro by a modified electromobility shift assay. Furthermore, the EcR fragment expressed in yeast was functional and bound radioactively labelled ecdysteroid specifically. Ligand binding was greatly enhanced by the presence of a USP ligand binding domain. Therefore, ecdysteroids are capable of inducing heterodimer formation between EcR and USP, even when the binding of these receptor proteins to cognate DNA response elements does not occur. This capability may be a regulated aspect of ecdysteroid action during insect development.
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Affiliation(s)
- Markus Lezzi
- Institute for Cell Biology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
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Durica DS, Wu X, Anilkumar G, Hopkins PM, Chung ACK. Characterization of crab EcR and RXR homologs and expression during limb regeneration and oocyte maturation. Mol Cell Endocrinol 2002; 189:59-76. [PMID: 12039065 DOI: 10.1016/s0303-7207(01)00740-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report here complete coding sequences for the Uca pugilator homologs of the ecdysteroid (UpEcR) and retinoid-X receptors (UpRXR). Library screenings recovered cDNA clones containing a unique amino terminal open-reading frame (A/B domain) for each gene, most similar to insect B1 EcR and USP1/RXR isoforms. Splicing variants in the UpRXR ligand-binding domain were also identified, in a region critical for folding of Drosophila and lepidopteran USP. UpEcR and UpRXR proteins were able to associate, and both are required for binding to an ecdysteroid HRE; these interactions were not hormone-dependent. Ribonuclease protection assays (RPA) were conducted using A/B domain and 'common' (C or E) domain probes on RNA isolated from various stages of regenerating limb buds and ovaries. For several of the limb bud and ovarian stages examined, the relative level of A/B domain sequence protected was significantly less than common domain suggesting alternative amino terminal isoforms other than those isolated through cloning. This is the first report of UpEcR and UpRXR transcription during ovarian maturation, implicating the ovary as a potential target for hormonal control in Crustacea.
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Affiliation(s)
- David S Durica
- Department of Zoology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA.
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Gilbert LI, Rybczynski R, Warren JT. Control and biochemical nature of the ecdysteroidogenic pathway. ANNUAL REVIEW OF ENTOMOLOGY 2002; 47:883-916. [PMID: 11729094 DOI: 10.1146/annurev.ento.47.091201.145302] [Citation(s) in RCA: 336] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Molting is elicited by a critical titer of ecdysteroids that includes the principal molting hormone, 20-hydroxyecdysone (20E), and ecdysone (E), which is the precursor of 20E but also has morphogenetic roles of its own. The prothoracic glands are the predominate source of ecdysteroids, and the rate of synthesis of these polyhydroxylated sterols is critical for molting and metamorphosis. This review concerns three aspects of ecdysteroidogenesis: (a) how the brain neuropeptide prothoracicotropic hormone (PTTH) initiates a transductory cascade in cells of the prothoracic gland, which results in an increased rate of ecdysteroid biosynthesis (upregulation); (b) how the concentrations of 20E in the hemolymph feed back on the prothoracic gland to decrease rates of ecdysteroidogenesis (downregulation); and (c) how the prothoracic gland cells convert cholesterol to the precursor of E and then 20E, a series of reactions only now being understood because of the use of a combination of classical biochemistry and molecular genetics.
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Affiliation(s)
- Lawrence I Gilbert
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3280, USA.
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Jones G, Wozniak M, Chu Y, Dhar S, Jones D. Juvenile hormone III-dependent conformational changes of the nuclear receptor ultraspiracle. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2001; 32:33-49. [PMID: 11719067 DOI: 10.1016/s0965-1748(01)00077-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The identification of potential endogenous or synthetic ligands for orphan receptors in the steroid receptor superfamily is important both for discerning endogenous regulatory pathways and for designing receptor inhibitors. The insect nuclear receptor Ultraspiracle (USP), an ortholog of vertebrate RXR, has long been treated as an orphan receptor. We have tested here the fit of terpenoid ligands to the JH III-binding site of monomeric and homo-oligomeric USP from Drosophila melanogaster (dUSP). dUSP specifically bound juvenile hormone III (JH III), but not control farnesol or JH III acid, and also specifically changed in conformation upon binding of JH III in a fluorescence binding assay. Juvenile hormone III binding caused intramolecular changes in receptor conformation, and stabilized the receptor's dimeric/oligomeric quaternary structure. In both a radiometric competition assay and the fluorescence binding assay the synthetic JH III agonist methoprene specifically competed with JH III for binding to dUSP, the first demonstration of specific binding of a biologically active JH III analog to an insect nuclear receptor. The recombinant dUSP bound with specificity to a DR12 hormone response element in a gel shift assay. The same DR12 element conferred enhanced transcriptional responsiveness of a transfected juvenile hormone esterase core promoter to treatment of transfected cells with JH III, but not to treatment with retinoic acid or T3. The activity of JH III or JH III-like structures, but not structures without JH III biological activity, to bind specifically to dUSP and activate its conformational change, provide evidence of a terpenoid endogenous ligand for Ultraspiracle, and offer the prospect that synthetic, terpenoid structures may be discovered that can agonize or antagonize USP function in vivo.
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Affiliation(s)
- G Jones
- School of Biological Sciences, University of Kentucky, Lexington, KY 40506, USA
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47
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Hannan GN, Hill RJ. LcUSP, an ultraspiracle gene from the sheep blowfly, Lucilia cuprina: cDNA cloning, developmental expression of RNA and confirmation of function. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2001; 31:771-781. [PMID: 11378412 DOI: 10.1016/s0965-1748(00)00182-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A DNA sequence corresponding to most of the DNA-binding domain of a Lucilia cuprina ultraspiracle protein (LcUSP) was amplified by PCR from genomic DNA and cloned. This cloned fragment was used to screen a L. cuprina cDNA library and to isolate a full-length LcUSP encoding sequence within a 3800-bp cDNA clone. The conceptually translated amino acid sequence of this open reading frame (467 amino acids) was used in alignment comparisons and phylogenetic analyses to reveal that LcUSP most closely resembles DmUSP relative to other known insect nuclear hormone receptors. An antisense RNA probe specific for the 5' end of Lcusp was used in ribonuclease protection assays to detect significant levels of Lcusp RNA throughout L. cuprina development. Highest levels were detected in embryos, late third instar larvae, pupae and adult females. This pattern parallels the pattern of expression observed for Dmusp RNAs during Drosophila melanogaster development. Finally, the LcUSP sequence was engineered for expression in mammalian cells and we now report that the cloned LcUSP is functional in vivo and can act as a partner for a chimeric L. cuprina ecdysone receptor to form an ecdysteroid-dependent transcription factor in mammalian cells.
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Affiliation(s)
- G N Hannan
- CSIRO Molecular Science, Sydney Laboratory, PO Box 184, North Ryde, NSW 2113, Australia.
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Biyasheva A, Do TV, Lu Y, Vaskova M, Andres AJ. Glue secretion in the Drosophila salivary gland: a model for steroid-regulated exocytosis. Dev Biol 2001; 231:234-51. [PMID: 11180965 DOI: 10.1006/dbio.2000.0126] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Small hydrophobic hormones like steroids control many tissue-specific physiological responses in higher organisms. Hormone response is characterized by changes in gene expression, but the molecular details connecting target-gene transcription to the physiology of responding cells remain elusive. The salivary glands of Drosophila provide an ideal model system to investigate gaps in our knowledge, because exposure to the steroid 20-hydroxyecdysone (20E) leads to a robust regulated secretion of glue granules after a stereotypical pattern of puffs (activated 20E-regulated genes) forms on the polytene chromosomes. Here, we describe a convenient bioassay for glue secretion and use it to analyze mutants in components of the puffing hierarchy. We show that 20E mediates secretion through the EcR/USP receptor, and two early-gene products, the rbp(+) function of BR-C and the Ca2+ binding protein E63-1, are involved. Furthermore, we demonstrate that 20E treatment of salivary glands leads to Ca2+ elevations by a genomic mechanism and that elevated Ca2+ levels are required for ectopically produced E63-1 to drive secretion. The results presented establish a connection between 20E exposure and changes in Ca2+ levels that are mediated by Ca2+ effector proteins, and thus establish a mechanistic framework for future studies.
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Affiliation(s)
- A Biyasheva
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Chicago, Illinois 60611-3093, USA
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Riddiford LM, Cherbas P, Truman JW. Ecdysone receptors and their biological actions. VITAMINS AND HORMONES 2001; 60:1-73. [PMID: 11037621 DOI: 10.1016/s0083-6729(00)60016-x] [Citation(s) in RCA: 362] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- L M Riddiford
- Department of Zoology, University of Washington, Seattle 98195-1800, USA
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50
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Baehrecke EH. Steroid regulation of programmed cell death during Drosophila development. Cell Death Differ 2000; 7:1057-62. [PMID: 11139278 DOI: 10.1038/sj.cdd.4400753] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Steroid hormones play an important role in the regulation of numerous physiological responses, but the mechanisms that enable these systemic signals to trigger specific cell changes remain poorly characterized. Recent studies of Drosophila illustrate several important features of steroid-regulated programmed cell death. A single steroid hormone activates both cell differentiation and cell death in different tissues and at multiple stages during development. While several steroid-regulated genes are required for cell execution, most of these genes function in both cell differentiation and cell death, and require more specific factors to kill cells. Genes that regulate apoptosis during Drosophila embryogenesis are induced by steroids in dying cells later in development. These apoptosis genes likely function downstream of hormone-induced factors to serve a more direct role in the death response. This article reviews the current knowledge of steroid signaling and the regulation of programmed cell death during development of Drosophila.
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Affiliation(s)
- E H Baehrecke
- Center for Agricultural Biotechnology, University of Maryland Biotechnology Institute, College Park, Maryland, MD 20742, USA.
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