Identification of promoter region of ghrelin gene in human medullary thyroid carcinoma cell line
Identification of promoter region of ghrelin gene in human medullary thyroid carcinoma cell line
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DOI：
10.1016/j.lfs.2004.04.028
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发表时间：
2004-09-17
期刊：
影响因子：
6.1
通讯作者：
Tanaka, M
中科院分区：
文献类型：
--
作者：
Nakai, N;Kaneko, M;Tanaka, M
Ghrelin是生长激素促分泌素受体的内源性配体，刺激生长激素的分泌。ghrelin基因在胃中表达最丰富。mRNA也在其他组织和细胞系中检测到。然而，ghrelin基因的转录调控机制尚未阐明。在本研究中，我们研究了生长素释放肽基因在人甲状腺髓样癌细胞系（TT细胞）中表达的调控区。对人生长素释放肽基因5 ′-区的PCR分析揭示了对应于小鼠生长素释放肽基因的短的非编码第一外显子的第一外显子的存在。第一个外显子位于以前报道的人ghrelin基因5 '端上游502位。RT-PCR分析显示第一外显子在胃和TT细胞中表达。用5 '-RACE方法证实了第一外显子在人胃中的表达。通过荧光素酶测定，在1225-1107中通过翻译起始位点的上游区域观察到显著水平的启动子活性。用TT细胞核提取物进行电泳迁移率变动分析，检测与启动子区-1129 ~-1100的特异性蛋白结合。这些结果提示，TT细胞ghrelin基因的表达可能受第一外显子上游调控。(C)2004爱思唯尔公司All rights reserved.
Ghrelin, an endogenous ligand for growth hormone (GH) secretagogue receptor, stimulates GH secretion. The ghrelin gene is expressed most abundantly in stomach. The mRNA is also detected in other tissues and cell lines. However, the mechanism of the transcriptional regulation of the ghrelin gene has not yet been clarified. In the present study, we have investigated the regulatory region of the ghrelin gene expression in the human medullary thyroid carcinoma cell line (TT cells). PCR analysis of the 5'-region for human ghrelin gene revealed the presence of the first exon corresponding to the short non-coding first exon of the mouse ghrelin gene. The first exon is located at the 502 by upstream from the 5'-end of the formerly reported human ghrelin gene. RT PCR analysis showed the expression of the first exon in the stomach and TT cells. The expression of the first exon in the human stomach was confirmed by 5'-RACE method. Significant level of promoter activity was observed in the 1225-1107 by up-stream region of the translation initiation site by luciferase assay. Specific protein binding to the promoter region of -1129 to -1100 was detected by electrophoretic mobility shift assay with nuclear extract from TT cells. These results suggest that the ghrelin gene expression in TT cells might be regulated by the upstream region of the first exon. (C) 2004 Elsevier Inc. All rights reserved.