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The gastrin gene expression and transcriptional regulation

胃泌素基因表达和转录调控

基本信息

批准号：
08670614
负责人：
SHIOTANI Akiko
金额：
$ 1.22万
依托单位：
Wakayama Medical College
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08670614/
关键词：
Gastrin gene Sp1 EGF Okadaic acid PGE_2 転写制御 gERE Sp1 Okadaic acid bFGF

项目摘要

Sp1 nuclear levels have been shown to directly correlate with the proliferative state of the cells. It is known that EGF receptor is activated by a series of reaction of phosphorylation, and post-transcriptional modification of Sp1 by phosphorylation and glycosylation has been correlated with Sp1 transcriptional activation in vitro. We therefore studied changes in the Sp1 nuclear levels in a rat pituitary cell line GH4 stimulated by EGF and Okadaic acid which is a phosphatase inhibitor. Using nuclear extracts from GH4 cells treated with l0nM EGF foe at least 16h, Sp1 binding decreased without a significant changes in the gERE1 and 2 complexes. Immunoblot analysis using the nuclear extracts treated with EGF showed that there was a decrease in the nuclear levels of Sp1. Pretreatment with EGF had little effect on the basal activity of the gastrin promoter. However, the the basal activity was decrease in basal activation of mutated gERE and Sp1 element which confer higher basal activity than the gERE.Treatment of the cells with okadaic acid alone resulted in a similar or greater decrease in Sp1 nuclear levels compared with EGF alone. Treatment of the cells with both EGF and okadaic acid had a synergistic effect, further depressing nuclear levels of Sp1. The loss of Sp1 was observed with EGF and augmented by okadaic acid, suggesting that activation of the EGF receptor phosphorylates Sp1 through increased intracellular serine/threonine protein kinase activity.

Sp1 核水平已被证明与细胞的增殖状态直接相关。已知EGF受体通过一系列磷酸化反应被激活，并且Sp1的磷酸化和糖基化的转录后修饰与体外Sp1转录激活相关。因此，我们研究了 EGF 和冈田酸（一种磷酸酶抑制剂）刺激的大鼠垂体细胞系 GH4 中 Sp1 核水平的变化。使用来自用10nM EGF敌人处理至少16小时的GH4细胞的核提取物，Sp1结合减少而gERE1和2复合物没有显着变化。使用经 EGF 处理的核提取物进行的免疫印迹分析表明，Sp1 的核水平有所下降。 EGF预处理对胃泌素促进剂的基础活性几乎没有影响。然而，突变的gERE和Sp1元件的基础活性降低了基础活性，其赋予比gERE更高的基础活性。与单独的EGF相比，单独用冈田酸处理细胞导致Sp1核水平类似或更大的降低。用 EGF 和冈田酸处理细胞具有协同作用，进一步抑制 Sp1 的核水平。使用 EGF 观察到 Sp1 的丢失，并通过冈田酸增强，这表明 EGF 受体的激活通过增加细胞内丝氨酸/苏氨酸蛋白激酶活性来磷酸化 Sp1。