Related Experiment Videos
CGP 52608-induced cyst formation in dinoflagellates: possible involvement of a nuclear receptor for melatonin
1Department of Biology, Hong Kong, University of Science and Technology, Kowloon, Hong Kong.
Abstract:
Melatonin has been shown to regulate gene transcription through RZR/ROR nuclear receptors in mammalian cells. Thiazolidine dione CGP 52608 is a selective agonist of RZR/ROR receptors with little or no affinity for the cell surface G protein-coupled melatonin receptors. In this study, we addressed whether nuclear signaling may be involved in indoleamine-induced encystment of the unicellular dinoflagellates by examining their responses to CGP 52608. Three species of dinoflagellates (Alexandrium catenella, Amphidinium carterae, and Crypthecodinium cohnii) encysted in the presence of CGP 52608 and the responses were reversible and dose-dependent. Since a previous study has implicated the involvement of G proteins in mediating indoleamine-induced encystment of dinoflagellates, we explored the possibility of cross-talks between G protein-dependent and nuclear signaling pathways. The responses of A. catenella to either mastoparan (a direct activator of mammalian G proteins) or indoleamines were assessed in the presence or absence of CGP 52608. Interestingly, CGP 52608 synergized with either indoleamines or mastoparan to produce a more rapid encystment response. These findings suggest that nuclear signaling may be involved in the indoleamine-induced encystment of dinoflagellates.
Insights
Nuclear signaling, potentially through RZR/ROR receptors, may drive dinoflagellate encystment. A compound called CGP 52608 induced encystment in three dinoflagellate species, suggesting a role for nuclear pathways in this process.
Area of Science:
- Microbiology
- Molecular Biology
- Cell Biology
Background:
- Melatonin regulates gene transcription via RZR/ROR nuclear receptors in mammals.
- CGP 52608 is a selective RZR/ROR agonist, distinct from cell surface melatonin receptors.
- Indoleamines can induce encystment in dinoflagellates, with prior studies suggesting G protein involvement.
Purpose of the Study:
- To investigate the role of nuclear signaling in indoleamine-induced dinoflagellate encystment.
- To determine if CGP 52608, a nuclear RZR/ROR agonist, can induce encystment in dinoflagellates.
- To explore potential cross-talk between G protein-dependent and nuclear signaling pathways in dinoflagellate encystment.
Main Methods:
- Testing the encystment response of three dinoflagellate species (A. catenella, A. carterae, C. cohnii) to CGP 52608.
- Assessing the reversibility and dose-dependency of CGP 52608-induced encystment.
- Evaluating the synergistic effects of CGP 52608 with indoleamines or mastoparan on A. catenella encystment.
Main Results:
- CGP 52608 induced encystment in Alexandrium catenella, Amphidinium carterae, and Crypthecodinium cohnii.
- The encystment responses to CGP 52608 were reversible and dose-dependent.
- CGP 52608 synergized with indoleamines and mastoparan to accelerate encystment in A. catenella.
Conclusions:
- Nuclear signaling pathways, potentially involving RZR/ROR receptors, are implicated in dinoflagellate encystment.
- Evidence suggests cross-talk between G protein-dependent and nuclear signaling in mediating dinoflagellate encystment.
- These findings highlight a novel mechanism for regulating dinoflagellate life cycle transitions.