A negative regulatory element in the promoter region of the rat alpha 2A-adrenergic receptor gene overlaps an SP1 consensus binding site.
A negative regulatory element in the promoter region of the rat alpha 2A-adrenergic receptor gene overlaps an SP1 consensus binding site.
复制标题
大鼠 α2A 肾上腺素受体基因启动子区域的负调控元件与 SP1 共有结合位点重叠。
DOI：
10.1042/bj3110541
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Gavras,H
中科院分区：
文献类型：
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作者：
Handy,DE;Zanella,MT;Kanemaru,A;Tavares,A;Flordellis,C;Gavras,H
α 2-肾上腺素能受体的三种亚型（α 2A、α 2B和α 2C）已被描述，它们的初级序列和组织特异性表达不同，由三种不同的基因编码。先前的研究表明，人类α 2a -肾上腺素能受体基因启动子由一个TATA-box （TATAAA）、一个回文序列（CCCACGTGGG）和一个GC-box （GGGGCGG）基序组成。对大鼠α 2a -肾上腺素能受体基因启动子区域的序列分析表明，这些启动子区域在序列和相对位置上是保守的。我们使用RINm5F分析了这些区域的转录活性，RINm5F是一种表达内源性α 2a -肾上腺素能受体基因的大鼠胰岛素瘤细胞系。这些结果表明-484 ~ -92区域对转录有负面影响，因为在α 2a -肾上腺素能受体基因-氯霉素乙酰转移酶报告基因中缺失该区域会增加报告基因的活性。该区域包括GC-box序列，该序列是核因子SP1的一致结合位点，SP1是转录的正激活因子。用一种识别SP1的抗体进行凝胶迁移和超迁移实验显示SP1核因子以及其他核因子与这个GC-box区域结合。附加的核因子结合到下游的回文区。我们认为，正作用和负作用的核因子有助于α 2-肾上腺素能受体启动子的活性。
Three subtypes of alpha 2-adrenergic receptors (alpha 2A, alpha 2B and alpha 2C) have been described that differ in their primary sequence and tissue-specific expression and are encoded by three distinct genes. Previous work has shown that the human alpha 2A-adrenergic receptor gene promoter consists of a TATA-box (TATAAA), palindromic sequence (CCCACGTGGG) and GC-box (GGGGCGG) motif. Sequence analysis of the putative promoter region of the rat alpha 2A-adrenergic receptor gene showed that these promoter regions are conserved in their sequence and relative location. We analysed the transcriptional activity of these regions using RINm5F, a rat insulinoma cell line that expresses the endogenous alpha 2A-adrenergic receptor gene. These results showed that the region from -484 to -92 has a negative effect on transcription, as deletion of this region in alpha 2A-adrenergic receptor gene-chloramphenicol acetyltransferase reporter constructs increased reporter gene activity. This region included the GC-box sequence which is a consensus binding site for the nuclear factor SP1, which is a positive activator of transcription. Gel-mobility-shift assays and supershift assays with an antibody that recognizes SP1 showed binding of the SP1 nuclear factor as well as other nuclear factors to this GC-box region. Additional nuclear factors bind to the downstream palindromic region. We suggest that positive- and negative-acting nuclear factors contribute to the activity of the alpha 2-adrenergic receptor promoter.