CGP 52608-induced cyst formation in dinoflagellates: Possible involvement of a nuclear receptor for melatonin
Article first published online: 30 JAN 2007
Journal of Pineal Research
Volume 21, Issue 2, pages 101–107, September 1996
How to Cite
Tsitn, S.-T., Wong, J. T.Y. and Wong, Y. H. (1996), CGP 52608-induced cyst formation in dinoflagellates: Possible involvement of a nuclear receptor for melatonin. Journal of Pineal Research, 21: 101–107. doi: 10.1111/j.1600-079X.1996.tb00276.x
- Issue published online: 30 JAN 2007
- Article first published online: 30 JAN 2007
- Received April 16,1996; accepted June 21, 1996.
- CGP 52608;
- nuclear receptor
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.