The role in spawning of a putative serotonin receptor isolated from the germ and ciliary cells of the gonoduct in the gonad of the Japanese scallop, Patinopecten yessoensis.
Serotonin (5-hydroxytriptamin, 5-HT) triggers germinal vesicle breakdown (GVBD) of oocytes and the transporting of the mature oocyte through the gonoduct via cilia motility in bivalves. The 5-HT receptor in the oocyte membrane of the Japanese scallop, Patinopecten yessoensis, has been pharmacologically characterized as a mixed profile of 5-HT(1)/5-HT(2) and is induced by estradiol-17beta (E(2)). Here we report the isolation, cloning, and tissue expression of the 5-HT receptor from the gonad of the Japanese scallop. A full-length cDNA (1818 bp) encoding a putative 5-HT receptor (5-HT(py)) of 454 amino acid residues was isolated from the ovary and shared 53.3% and 40.2% homology with the Aplysia 5-HT(1ap) and mouse 5-HT(1A), respectively. The 5-HT(py) sequence possessed typical characteristics of 5-HT(1), including seven transmembrane domains, a long third inner loop, and a short fourth inner terminal. Phylogenetic analysis suggested that 5-HT(py) was classified into the 5-HT(1) subtype as well as other invertebrate 5-HT(1) receptors. Semi-quantitative RT-PCR showed the expression of the 5-HT(py) gene in both the nervous system and peripheral tissues and the induction of expression by E(2) in the ovarian tissue. In situ hybridization revealed a strong 5-HT(py) signal in the oocytes, spermatids, and ciliary epithelium of the gonoducts in the ovary and testis. These results suggest that the effects of 5-HT on the induction of oocyte maturation, sperm motility, and transport of mature oocytes and sperm through the ciliated epithelium of the gonoducts are mediated by 5-HT(py).
Tanabe
Toru
T
Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan.
Yuan
Yuan
Y
Nakamura
Satoshi
S
Itoh
Naoki
N
Takahashi
Keisuke G
KG
Osada
Makoto
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005260:Female; D006066:Gonads / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D049897:Pectinidae / Q000235:genetics / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012701:Serotonin / Q000235:genetics
D011985:Receptors, Serotonin; D012701:Serotonin