Structural and functional multiplicity of the kisspeptin/GPR54 system in goldfish (Carassius auratus).
To ascertain the neuroendocrine function of the kisspeptin/GPR54 system in non-mammalian species, full-length cDNAs encoding for Kiss1 and Kiss2 as well as their putative cognate receptors GPR54a and GPR54b, were isolated from goldfish (Carassius auratus). The deduced protein sequences between Kiss1 and Kiss2 in goldfish share very low similarity, but their putative mature peptides (kisspeptin-10) are relatively conserved. RT-PCR analysis demonstrated that the goldfish kiss1 gene (gfkiss1) is highly expressed in the optic tectum-thalamus, intestine, kidney, and testis, while the goldfish kiss2 gene (gfkiss2) is mainly detected in the hypothalamus, telencephalon, optic tectum thalamus, adipose tissue, kidney, heart, and gonads. The two receptor genes (gfgpr54a and gfgpr54b) are highly expressed in the brain regions including telencephalon, optic tectum thalamus, and hypothalamus. Both mature goldfish kisspeptin-10 peptides (gfKiss1-10 and gfKiss2-10) are biologically active as they could functionally interact with the two goldfish receptors expressed in cultured eukaryotic cells to trigger the downstream signaling pathways with different potencies. The actions of gfKiss1-10 and gfKiss2-10 on LH secretion were further investigated in vitro and in vivo. Intraperitoneal administration of gfKiss1-10 to sexually mature female goldfish could increase the serum LH levels. However, this peptide does not significantly influence LH release from goldfish pituitary cells in primary culture, indicating that the peptide does not exert its actions at the pituitary level. On the other hand, gfKiss2-10 appears to be a much less potent peptide as it exhibits no significant in vivo bioactivity and is also inactive on the primary pituitary cells.
Li
Shuisheng
S
State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, People's Republic of China.
Zhang
Yong
Y
Liu
Yun
Y
Huang
Xigui
X
Huang
Weiren
W
Lu
Danqi
D
Zhu
Pei
P
Shi
Yu
Y
Cheng
Christopher H K
CH
Liu
Xiaochun
X
Lin
Haoran
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis / Q000302:isolation & purification; D005260:Female; D006054:Goldfish / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014018:Tissue Distribution; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*
D018076:DNA, Complementary; D043562:Receptors, G-Protein-Coupled; D025521:Tumor Suppressor Proteins