| GeneLibs

题目:: Proximal cyclic AMP response element is essential for exendin-4 induction of rat EGR-1 gene.
作者:: Kang(Jung-Hoon),Kim(Myung-Jun),Jang(Hwa-In),Koh(Kyung-Hee),Yum(Keun-Sang),Rhie(Duck-Joo),Yoon(Shin Hee),Hahn(Sang June),Kim(Myung-Suk),Jo(Yang-Hyeok)
状态:: 发布时间2007-01-04 , 更新时间 2013-11-21
期刊:: Am J Physiol Endocrinol Metab
摘要:: Glucagon-like peptide-1 and its potent agonist exendin-4 induce several immediate early response genes (IEGs) that code for transcription factors implicated in cell proliferation, differentiation, and apoptosis. We recently observed that early growth response factor-1 (EGR-1), an IEG product, was required for transcriptional activation of Ccnd1 (cyclin D1) gene by exendin-4. Herein, the regulatory mechanism whereby exendin-4 activates the transcription of EGR-1 gene was investigated in the pancreatic beta-cell line INS-1. Deletion analysis of rat EGR-1 promoter identified a critical region between -73 and -46 for the activation of EGR-1 in response to exendin-4. Mutation of the proximal putative cAMP response element (CRE, 5'-GTACGTCA-3') located at -69 resulted in a significant decrease in the EGR-1 transcription, whereas the mutation of the distal putative CRE at -139 was without such an effect. In immune supershift assays using exendin-4-treated cells, binding of cAMP response element-binding protein (CREB) phosphorylated on Ser(133) to the proximal CRE was increased. Employment of a CREB mutant containing Ala substitution at Ser(133) or a dominant negative CREB mutant that inhibits the binding of endogenous CREB to DNA significantly decreased the exendin-4-induced EGR-1 transcription. In experiments using specific protein kinase inhibitors, the effect of H-89 was more prominent than PD-98059, indicating the predominance of the PKA signaling over the MEK/ERK in induction of EGR-1. Therefore, it appears that the proximal CRE site is critical and the binding with CREB phosphorylated on Ser(133) is necessary for induction of the EGR-1 transcription by exendin-4.
语言:: eng
DOI:: 10.1152/ajpendo.00181.2006

文献库文献相关信息

DataTable pData

联系方式

微信公众号

文献库 文献相关信息

DataTable pData

联系方式

微信公众号

文献库文献相关信息