Genomic organization of the 5' end of human beta-ENaC and preliminary characterization of its promoter.
Genomic organization of the 5' end of human beta-ENaC and preliminary characterization of its promoter.
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人 β-ENaC 5 端的基因组结构及其启动子的初步表征。
DOI：
10.1152/ajprenal.00268.2001
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Itani,OmarA
中科院分区：
文献类型：
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作者：
Thomas,ChristieP;Loftus,RandyW;Liu,KangZ;Itani,OmarA
上皮Na+通道β亚基（β-ENaC）的mRNA在发育过程中受到调节，在某些组织中，对皮质类固醇有反应。为了了解人β-ENaC基因的转录调控机制，我们对该基因的5′端及其5′侧翼区进行了分析。采用5′端快速扩增技术扩增了连接接头的人肾和肺cDNA，并通过核酸酶保护或引物延伸分析确定了两个5′端变异转录本的转录起始位点。分离出含有该基因5′端的粘粒克隆，对这些克隆的分析表明，间隔约1.5 kb的交替第一外显子和共同的第二外显子上游约45 kb形成了这些转录本的基础。包括任一转录本近端5′侧翼区的基因组片段能够指导报告基因在肺上皮中的表达，并结合核提取物中的Sp1，证实存在调节β-ENaC表达的单独启动子。
The mRNA for the β-subunit of the epithelial Na+channel (β-ENaC) is regulated developmentally and, in some tissues, in response to corticosteroids. To understand the mechanisms of transcriptional regulation of the human β-ENaC gene, we characterized the 5′ end of the gene and its 5′-flanking regions. Adaptor-ligated human kidney and lung cDNA were amplified by 5′ rapid amplification of cDNA ends, and transcription start sites of two 5′ variant transcripts were determined by nuclease protection or primer extension assays. Cosmid clones that contain the 5′ end of the gene were isolated, and analysis of these clones indicated that alternate first exons ∼1.5 kb apart and ∼ 45 kb upstream of a common second exon formed the basis of these transcripts. Genomic fragments that included the proximal 5′-flanking region of either transcript were able to direct expression of a reporter gene in lung epithelia and to bind Sp1 in nuclear extracts, confirming the presence of separate promoters that regulate β-ENaC expression.