Molecular cloning and gene expression of the gonadotropin-releasing hormone receptor in the orange-spotted grouper, Epinephelus coioides.
The objective of this study was to investigate the molecular mechanisms of gonadotropin-releasing hormone receptor (GnRH-R) involved in the endocrine regulation of reproduction in the orange-spotted grouper, Epinephelus coioides. The full-length cDNA encoding GnRH-R type I was successfully cloned from the pituitary by reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) methods in the grouper. The complete GnRH-R type I cDNA is 1607 bp, which includes an open reading frame of 1092 bp encoding a protein of 364 amino acids, a seven-alpha helix transmembrane domain, a N-terminal extracellular domain, and a C-terminal cytoplasmic domain. The expression of GnRH-R type I was found to be highest in the pituitary. An intramuscular injection of various GnRH types in vivo was attempted. The expression of GnRH-R type I was stimulated by a single injection of salmon GnRH, while in the case of chicken GnRH II treatment, the expression of GnRH-R type I was inhibited. This suggests that the action of chick GnRH II is probably enhanced through the GnRH receptor of different forms. Furthermore, none of them were expressed by an injection of seabream GnRH, and this is likely attributed to the injection dose being below the threshold level, and this remains to be further examined. In conclusion, GnRHs of various types are effective in stimulating the expression of gonadotropins through various forms of the GnRH-R, and multiple forms of the receptor gene likely exist in teleosts.
Hsieh
S L
SL
Department of Nutrition and Health Science, Fooyin University, Kaohsiung 831, Taiwan.
Chuang
H C
HC
Nan
F H
FH
Ruan
Y H
YH
Kuo
C M
CM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D016000:Cluster Analysis; D019295:Computational Biology; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics*; D010802:Phylogeny; D010902:Pituitary Gland / Q000378:metabolism; D011966:Receptors, LHRH / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D018076:DNA, Complementary; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone