A dominant-negative human growth hormone-releasing hormone (GHRH) receptor splice variant inhibits GHRH binding.
نویسندگان
چکیده
GHRH is a hypothalamic peptide that stimulates the synthesis and secretion of GH from pituitary somatotroph cells. The GHRH receptor is a seven-transmembrane G protein-coupled receptor that localizes to the surface of somatotroph cells and binds GHRH. Alternative splicing of the GHRH receptor primary transcript at the intron/exon boundary 3' of exon 11 results in inclusion of sequence that is normally intronic. In the human, this inclusion has an in-frame premature stop codon, and this variant mRNA encodes a protein truncated just before the sixth transmembrane domain. To identify the effects of the truncated receptor on signaling of the wild-type receptor and the mechanisms by which its effects are produced, the full-length and truncated receptor constructs were epitope tagged and transfected into HeLa T4 cells to examine signaling and expression. Results show that the truncated GHRH receptor cannot signal through the cAMP pathway and acts as a dominant inhibitor of wild-type receptor signaling. The wild-type and truncated GHRH receptor proteins form a complex. Stably transfected cell lines were generated to examine the mechanism of signal inhibition by the truncated receptor. The data show that receptor cell surface expression is not altered when the wild-type and truncated receptors are cotransfected, but that truncated receptor coexpression substantially reduces GHRH binding by the wild-type receptor. The results support an important role for alternative splicing in mediating the effects of G protein-coupled receptors in general, and suggest that the GHRH receptor can form multimers, which may be important to its signaling properties.
منابع مشابه
بررسی چند شکلی ژنتیکی و فراوانی آللی جایگاه ژنی GHRH (Growth-hormone-releasing hormone) در گاوهای سرابی ایران
انتخاب حیوان بر اساس نشانگرهای مولکولی یکی از جدیدترین روشهای اصلاحی است که می‌تواند باعث بهبود صحت پیش‌بینی و پاسخ به انتخاب شود. GHRH (Growth-hormone-releasing hormone) یکیازژنهایبرگزیدهبرایاستراتژی‌هایانتخاببراساسمارکرمی‌باشد.براساسگزارشاتموجود، چندشکلی‌هایژن بهطورمعنی‌داریباصفاتاجزایشیروتولیدآنارتباطدارد. به منظور بررسی چندشکلی (پلی‌مورفیسم) مکان ژنی GHRH در نژاد سرابی، از 112 رأس گاو ...
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ورودعنوان ژورنال:
- Endocrinology
دوره 147 4 شماره
صفحات -
تاریخ انتشار 2006