title: Orange-spotted grouper (Epinephelus coioides) orexin: molecular cloning, tissue expression, ontogeny, daily rhythm and regulation of NPY gene expression.
abstract: Orexin-A and -B, collectively called orexins, are hypothalamic neuropeptides involved in the regulation of food intake, sleep and energy balance. In this study, the full-length cDNA of prepro-orexin was isolated from the hypothalamus of orange-spotted grouper (Epinephelus coioides) using RT-PCR and RACE. The grouper prepro-orexin cDNA is 711 bp in length and encodes a 149-amino acid precursor protein that contains a 46-amino acid signal peptide, a 43-amino acid mature orexin-A peptide, a 27-amino acid mature orexin-B peptide and a 33-amino acid C terminus of unknown function. The tissue distribution and ontogeny of prepro-orexin were examined by quantitative real-time PCR. We found that the prepro-orexin mRNA is widely expressed in brain and peripheral tissues, with abundant expression in the hypothalamus. During the embryonic development, prepro-orexin mRNA was first detected in neurula stage embryos, and its expression gradually increased during the remainder of embryogenesis. Our analysis of grouper hypothalamic prepro-orexin expression showed that prepro-orexin mRNA levels were greater in the light phase than in the dark phase and increased significantly at meal-time. Intraperitoneal injection of orexin-A caused a dose-related increase in hypothalamus NPY mRNA expression level after 4h. Orexin-A also increased NPY mRNA expression level from static hypothalamic fragments incubation. Our results imply that orexin may be involved in feeding in the orange-spotted grouper and orexin-A is a stimulator of NPY mRNA expression in vivo and in vitro.
authors: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou 510275, China.
authors: Aifen
authors: A
authors: Yan
authors: Lingjuang
authors: L
authors: Zhang
authors: Zhiguo
authors: Z
authors: Tang
authors: Yanhong
authors: Y
authors: Zhang
authors: Chaobin
authors: C
authors: Qin
authors: Bo
authors: B
authors: Li
authors: Wensheng
authors: W
authors: Li
authors: Haoran
authors: H
authors: Lin