title: The mechanism of regulation of ovarian maturation by red pigment concentrating hormone in the mud crab Scylla paramamosain.
abstract: In this study a full-length cDNA (Sp-RPCH) was cloned from the eyestalk ganglia of the mud crab Scylla paramamosain. Sp-RPCH is 660 base pairs in length and its open reading frame encodes a precursor that is predicted to be processed into a 25-residue signal peptide, a mature red pigment concentrating hormone (RPCH, an octapeptide), and a 75-residue precursor-related peptide. Phylogenetic analysis indicates that it clusters with other crustacean RPCHs and belongs to the adipokinetic hormone/RPCH peptide superfamily. Sp-RPCH gene expression was detected, using an end-point polymerase chain reaction (PCR), not only in the eyestalk ganglia but also in the brain and thoracic ganglia. Quantified using a real-time PCR, Sp-RPCH gene expression levels in the three tissues fluctuated along a cycle of ovarian maturation, with the levels progressively increased from stages I to IV, after which the expression levels decreased (although they remained significantly higher than stage I levels) when the ovary reached the mature stage (stage V). It was demonstrated using a patch clamp analysis that synthetic RPCH was able to evoke a Ca(2+) current in dissociated brain neurons and synthetic RPCH significantly increased the mean oocyte diameter of the ovarian tissues co-cultured with the eyestalk ganglia, brain, or thoracic ganglia; the stimulatory effect of RPCH was absent when the nervous tissues were not included in the ovarian incubation. Animals administrated with RPCH had significantly higher levels of gonad-somatic index, hepatopancreas-somatic index, and vitellogenin gene expression, when compared to control animals receiving a saline injection. The combined results clearly show that RPCH is involved in ovarian maturation in the mud crab; the stimulatory effects of RPCH are likely mediated by its actions on the release from the nervous tissues of factor(s) that directly regulate vitellogenesis in the ovary and hepatopancreas.
authors.affiliation: College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zeng
authors.affiliation: College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
authors.forename: Chenchang
authors.initials: C
authors.lastname: Bao
authors.affiliation: College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
authors.forename: Huiyang
authors.initials: H
authors.lastname: Huang
authors.affiliation: College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; Collaborative Innovation Center for Development and Utilization of Marine Biological Resources, Xiamen 361102, China. Electronic address: haihuiye@xmu.edu.cn.
authors.forename: Haihui
authors.initials: H
authors.lastname: Ye
authors.affiliation: College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
authors.forename: Shaojing
authors.initials: S
authors.lastname: Li
mesh_terms: D000818:Animals; D003386:Brachyura / Q000502:physiology*; D003001:Cloning, Molecular; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D009842:Oligopeptides / Q000378:metabolism*; D010053:Ovary / Q000254:growth & development* / Q000502:physiology; D016133:Polymerase Chain Reaction; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D012741:Sexual Maturation
chemical_list: D009842:Oligopeptides; C022059:red pigment-concentrating hormone; D011761:Pyrrolidonecarboxylic Acid
keywords: Neuroendocrine; Ovary; RPCH; Reproduction; Scylla paramamosain