Molecular cloning of three cDNAs encoding different GnRHs in the brain of barfin flounder.
To examine the reproductive endocrinology of a large pleuronectiform fish, barfin flounder, Verasper moseri, a promising candidate for aquaculture and resource enhancement in northern Japan due to its high commercial value, three gonadotropin-releasing hormones (GnRHs) in the brain was identified by isolation of their cDNAs. This species had three molecular forms of GnRH; salmon GnRH (sGnRH), chicken GnRH-II (cGnRH-II), and seabream GnRH (sbGnRH). Each GnRH cDNA encoded a signal peptide (SP), GnRH, and a GnRH-associated peptide (GAP), which was connected to GnRH by a Gly-Lys-Arg sequence. The sGnRH cDNA encoded an SP composed of 23 amino acids and a GAP composed of 54 amino acids. The cGnRH-II cDNA encoded an SP of 23 amino acids and a GAP of 49 amino acids. The sbGnRH cDNA encoded an SP of 26 amino acids and a GAP of 57 amino acids. In situ hybridization showed that the genes for sGnRH, cGnRH-II, and sbGnRH are expressed in the ventromedial olfactory bulbs and the terminal nerve ganglion, the midbrain tegmentum, and the preoptic area, respectively. These results indicate that sbGnRH neurons in the preoptic area are involved in gonadotropin secretion in barfin flounder.
Amano
Masafumi
M
School of Fisheries Sciences, Kitasato University, Sanriku Ofunato, Iwate 022-0101, Japan. amanoma@kitasato-u.ac.jp
Takahashi
Akiyoshi
A
Yamanome
Takeshi
T
Okubo
Kataaki
K
Aida
Katsumi
K
Yamamori
Kunio
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D005432:Flounder / Q000235:genetics*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000235:genetics*; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D021541:Sea Bream / Q000235:genetics; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; D007987:Gonadotropin-Releasing Hormone; C047717:LHRH, His(5)-Trp(7)-Tyr(8)-