Preferential ligand selectivity of the monkey type-II gonadotropin-releasing hormone (GnRH) receptor for GnRH-2 and its analogs.
Gonadotropin-releasing hormone (GnRH) regulates the reproductive system through the cognate GnRH receptor (GnRHR) in vertebrates. In this study, we cloned a cDNA encoding the full-length open reading frame sequence for green monkey type-II GnRHR (gmGnRHR-2) from the genomic DNA of CV-1 cells. Transient transfection study showed that gmGnRHR-2 was able to induce both c-fos promoter- and cAMP responsive element-driven transcriptional activities, indicating that gmGnRHR-2 couples to both Gs- and Gq/11-linked signaling pathways. gmGnRHR-2 responded better to GnRH-2 ([His5, Trp7, Tyr8]GnRH) than GnRH-1 ([Tyr5, Leu7, Arg8]GnRH). Substitutions of His5, Trp7, and/or Tyr8 in GnRH-1 increased the potency to activate gmGnRHR-2, suggesting that individual His5, Trp7, and Tyr8 in GnRH-2 contributed to differential ligand sensitivity of gmGnRHR-2. Substitution of D-Ala for Gly6 in GnRH-2 increased the potency to activate the receptor, suggesting that GnRH-2 has a constrained conformation when it binds to the receptor. GnRH-induced gmGnRHR-2 activation was specifically inhibited by GnRH-2 antagonists, Trptorelix-1 and -2, but not by a GnRH-1 antagonist, Cetrorelix. In conclusion, gmGnRHR-2 revealed preferential ligand selectivity for GnRH-2 and its analogs, suggesting that gmGnRHR-2 has a functional activity that is different from mammalian type-I GnRHRs but similar to non-mammalian GnRHRs.
Wang
Ai Fen
AF
Hormone Research Center, Chonnam National University, Gwangju 500-757, South Korea.
Li
Jian Hua
JH
Maiti
Kaushik
K
Kim
Wang Phil
WP
Kang
Hae Mook
HM
Seong
Jae Young
JY
Kwon
Hyuk Bang
HB
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D018076:DNA, Complementary / Q000235:genetics; D005822:Genetic Vectors; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D008024:Ligands; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D051381:Rats; D011966:Receptors, LHRH / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D014162:Transfection
D018076:DNA, Complementary; D008024:Ligands; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone; C047717:LHRH, His(5)-Trp(7)-Tyr(8)-