Akademik Veri Yönetim Sistemi
Federation of European Biochemical Societies, İstanbul, Türkiye, 5 - 09 Temmuz 2025, ss.365, (Özet Bildiri)
Isolated growth hormone deficiency (IGHD) is a medical condition of insufficient or lack of production of growth hormone (GH) and it occurs with an incidence between 1/4000 and 1/10 000 live births. Most of cases are sporadic and idiopathic but 5-30% of growth hormone deficiency (GHD) has a genetic etiology. IGHD is caused by mutations in GH-N gene or the mutations in GHRHR gene. We determined five missense (p.K264E, p.S317T, p.S330L, p.G369V, p.T257A9), one insertion (c.333_334insC, p.C112Lfs*10) and one nonsense (p.E72X) mutations in the Turkish population but their functions are not shown in GHRH-GHRHR signaling. The purpose of our research was to determine the function of mutations in GHRHR gene for GHRH-GHRHR signaling pathway. The QuikChange Site-directed Mutagenesis kit was used to generate mutations in GHRHR gene. Mutations in GHRHR gene were confirmed by DNA sequencing. At same time, CRE-luc reporter was prepared by us in order to show function of mutations in GHRHR. Wt and mutant GHRHR plasmids were cotransfected with Cre-luc reporter in CHO cells and expressed. Then the cells were treated with GHRH for 5 hours and their luciferase activity were measured. Five missense mutations (p.K264E, p.S317T, p.S330L, p.G369V, p.T257A9) one insertion (c.333_334insC) and one nonsense mutation (p.E72X) were created in wt GHRHR gene. The mutations in the GHRHR gene were confirmed by sequencing and CRE-luc reporter plasmid was successfully generated. Wt and mutants GHRHR were coexpressed with the CRE-luc reporter in CHO cells and the luciferase reporter assay results showed that p.K264E, p.S330L, p.G369V, p.S317T ve p.T257A mutations significantly reduced reporter activity. The cells expressing p.E72X and c.333_334insC mutations did not show any reporter activity. Mutations in GHRHR affect GHRH-GHRHR dependent cAMP signaling pathway.