Bigot Laetitia, Beets Isabel, Dubos Marie-Pierre, Boudry Pierre, Schoofs Liliane, Favrel Pascal
Université de Caen Basse-Normandie, Biologie des Organismes Aquatiques et Ecosystèmes (BOREA), CS 14032, 14032 Caen Cedex 05, France CNRS UMR 7208, BOREA, CS 14032, 14032 Caen Cedex 05, France.
Department of Biology, Functional Genomics and Proteomics Group, KU Leuven, 3000 Leuven, Belgium.
J Exp Biol. 2014 Aug 15;217(Pt 16):2974-82. doi: 10.1242/jeb.104067. Epub 2014 Jun 19.
Members of the short neuropeptide F (sNPF) family of peptides and their cognate receptors play key roles in a variety of physiological processes in arthropods. In silico screening of GigasDatabase, a specific expressed sequence tag database from the Pacific oyster Crassostrea gigas, resulted in the identification of a receptor (Cg-sNPFR-like) phylogenetically closely related to sNPF receptors (sNPFRs) of insects. A reverse endocrinology approach was undertaken to identify the peptide ligand(s) of this orphan receptor. Though structurally distinct from insect sNPFs, three RFamide peptides derived from the same precursor, i.e. GSLFRFamide, SSLFRFamide and GALFRFamide, specifically activate the receptor in a dose-dependent manner, with respective EC50 values (half-maximal effective concentrations) of 1.1, 2.1 and 4.1 μmol l(-1). We found that both Cg-sNPFR-like receptor and LFRFamide encoding transcripts are expressed in the oyster central nervous system and in other tissues as well, albeit at lower levels. Mass spectrometry analysis confirmed the wide distribution of LFRFamide mature peptides in several central and peripheral tissues. The Cg-sNPFR-like receptor was more abundantly expressed in ganglia of females than of males, and upregulated in starved oysters. In the gonad area, highest receptor gene expression occurred at the start of gametogenesis, when storage activity is maximal. Our results suggest that signaling of LFRFamide peptides through the Cg-sNPFR-like receptor might play a role in the coordination of nutrition, energy storage and metabolism in C. gigas, possibly by promoting storage at the expense of reproduction.
短神经肽F（sNPF）家族的肽及其同源受体在节肢动物的各种生理过程中发挥着关键作用。对来自太平洋牡蛎巨蛎（Crassostrea gigas）的特定表达序列标签数据库GigasDatabase进行电子筛选，鉴定出一种受体（类Cg-sNPFR），其在系统发育上与昆虫的sNPF受体（sNPFRs）密切相关。采用反向内分泌学方法来鉴定这种孤儿受体的肽配体。尽管在结构上与昆虫的sNPF不同，但源自同一前体的三种RFamide肽，即GSLFRFamide、SSLFRFamide和GALFRFamide，以剂量依赖的方式特异性激活该受体，其各自的EC50值（半数最大效应浓度）分别为1.1、2.1和4.1 μmol l(-1)。我们发现类Cg-sNPFR受体和编码LFRFamide的转录本在牡蛎中枢神经系统以及其他组织中均有表达，尽管表达水平较低。质谱分析证实LFRFamide成熟肽在几个中枢和外周组织中广泛分布。类Cg-sNPFR受体在雌性神经节中的表达比雄性更丰富，并且在饥饿的牡蛎中上调。在性腺区域，受体基因表达在配子发生开始时最高，此时储存活性最大。我们的结果表明，LFRFamide肽通过类Cg-sNPFR受体发出的信号可能在巨蛎的营养、能量储存和代谢协调中发挥作用，可能是通过以牺牲繁殖为代价促进储存来实现的。
