Molecular mechanism of inductive and inhibitory regulation in the spawning of marine bivalves : Analysis of a novel inhibitor from the central nervous system

5-羟色胺（5-HT）诱导的双壳贝类卵母细胞释放可被脑足神经节（CPG）的一种新因子和前列腺素F_（2 α）（PG F_（2 α））强烈抑制。PGF 2 α强烈抑制5-HT诱导的卵子释放，但不抑制卵母细胞成熟，因此表明PGF 2 α可能抑制5-HT诱导的性腺管纤毛运动。我们从扇贝CPG中发现了一种新的抑制5-HT诱导的卵母细胞成熟的因子，从而抑制卵子的释放。我们将这种新的抑制剂命名为卵母细胞成熟阻滞因子（OMAF）。结果表明，卵母细胞接受蛋白质OMAF，OMAF可能是抑制5-HT诱导卵母细胞成熟的一种普遍物质。B）OMAFOMAF的信号通路是通过血流转运到卵表面，通过5-HT受体介导，抑制5-HT诱导的卵母细胞成熟。 ...更多信息 在卵母细胞膜上，通过自己的接受机制。在细胞外Ca^<2+>存在的情况下，5-HT诱导卵母细胞成熟并随后通过性腺管释放卵子。OMAF抑制5-HT诱导的细胞内Ca^2+升高，表明OMAF抑制细胞外Ca^2+通过Ca^2+通道流入卵母细胞。c）扇贝5-HT cDNA（5-Htpy）的克隆及其结构和预测的功能用从第3位保守区设计的简并引物进行RT-PCR和随后的Nested PCR，第6和第7跨膜结构域及3 '、5' RACE。我们获得了约2.0kbp的5-HTpy cDNA，其开放阅读框编码454个氨基酸残基。5-HTpy与Gi偶联形成5-HT 1受体群，通过5-HTpy与Gi偶联的方式，在细胞内转导5-HT抑制cAMP的产生，并诱导细胞外Ca^2+内流进入卵母细胞，5-HT触发的双壳贝类产卵分别受性腺管和卵母细胞的PGF 2 α和OMAF调节，成熟卵母细胞停滞在减数分裂前期的网状期，直至产卵。少

a)Molecules related to the regulation of oocyte maturation and spawning in marine bivalvesThe serotonin (5-HT)-induced egg release has been strongly inhibited by a novel factor from the cerebral and pedal ganglion (CPG) and prostaglandin F2α (PG F2α). PG F2α strongly inhibited 5-HT-induced egg release, but not oocyte maturation, thus suggesting that PGF2α may suppress 5-HT-induced ciliary movement in the gonoduct. We found a novel factor from CPG of the scallop to inhibit 5-HT-induced oocyte maturation and thereby result in the suppression of egg release. We named the novel inhibitor Oocyte Maturation Arresting Factor (OMAF). It was demonstrated that the proteinaceous OMAF is received by a receptive mechanism of oocyte and OMAF appears to be a universal substance to inhibit 5-HT-induced oocyte maturation in bivalve species.b)Signaling pathway of OMAFOMAF is transported to egg surface through blood flow and inhibits oocyte maturation induced by 5-HT, which is mediated through 5-HT recep … More tor in the oocyte membrane, via a receptive mechanism of its own. 5-HT induced oocyte maturation and subsequent egg release through the gonoduct in the presence of extracellular Ca^<2+>. OMAF reduced an increase in intracellular Ca^<2+> induced by 5-HT, suggesting that the OMAF inhibits an extracellular Ca^<2+> influx into oocyte via Ca^<2+> channels.c)Scallop 5-HT cDNA (5-Htpy) cloning and the structure and predicted functionRT-PCR and subsequent Nested PCR were carried out using degenerate primers designed from the conservative region of 3rd, 6th and 7th transmembrane domains and 3', 5' RACE was followed. We obtained 5-HTpy cDNA of ca 2.0 kbp containing ORF encoding 454 amino acid residues. The 5-HTpy was clustered into 5-HT1 subtype receptor group coupled with Gi, in which the intracellular transduction of 5-HT via 5-HTpy coupled with Gi inhibits cAMP production and induces extracellular Ca^<2+> influx into oocyte.The spawning of bivalves triggered by 5-HT is regulated by PGF2α and OMAF at the gonoduct and oocyte, respectively, and full-grown oocyte is arrested at the dictyate stage of meiotic prophase until spawning. Less