Amino acids control mammalian gene transcription:: Activating transcription factor 2 is essential for the amino acid responsiveness of the CHOP promoter
Amino acids control mammalian gene transcription:: Activating transcription factor 2 is essential for the amino acid responsiveness of the CHOP promoter
复制标题
DOI：
10.1128/mcb.20.19.7192-7204.2000
复制
发表时间：
2000-10-01
影响因子：
5.3
通讯作者：
Fafournoux, P
中科院分区：
文献类型：
--
作者：
Bruhat, A;Jousse, C;Fafournoux, P
在哺乳动物中，氨基酸的血浆浓度受营养或病理状况的影响。已经明确的是，营养物质，尤其是氨基酸，参与基因表达的调控。在此我们研究了在氨基酸缺乏时参与调节CHOP（一种CCAAT/增强子结合蛋白[C/EBP]相关基因）表达的分子机制。我们先前已经表明，氨基酸浓度对CHOP mRNA表达的调节具有转录和转录后成分。我们报告了对亮氨酸饥饿诱导人CHOP基因转录激活所涉及的顺式和反式作用元件的分析。通过瞬时表达实验，我们表明一个顺式正性元件对CHOP启动子的氨基酸调节至关重要。这个序列是首次被描述的能够响应几种个别氨基酸的缺乏而调节基础启动子的序列，因此可被称为氨基酸反应元件（AARE）。此外，我们表明CHOP的AARE与C/EBP和ATF/CRE结合位点相关，并且在饥饿和非饥饿条件下在体外与激活转录因子2（ATF - 2）结合。利用ATF - 2缺陷型小鼠胚胎成纤维细胞和一种ATF - 2显性负性突变体，我们证明该转录因子的表达对于亮氨酸饥饿诱导的CHOP转录激活是必不可少的。总之，这些结果表明ATF - 2可能是一系列分子事件中的一个环节，通过这些分子事件，氨基酸的细胞浓度能够调节哺乳动物的基因表达。
In mammals, plasma concentration of amino acids is affected by nutritional or pathological conditions. It has been well established that nutrients, and particularly amino acids, are involved in the control of gene expression. Here we examined the molecular mechanisms involved in the regulation of CHOP (a CCAAT/enhancer-binding protein [C/EBP]-related gene) expression upon amino acid limitation, We have previously shown that regulation of CHOP mRNA expression by amino acid concentration has both transcriptional and posttranscriptional components. We report the analysis of cis- and trans-acting elements involved in the transcriptional activation of the human CHOP gene by leucine starvation. Using a transient expression assay, rye show that a cis-positive element is essential for amino acid regulation of the CHOP promoter. This sequence is the first described that can regulate a basal promoter in response to starvation for several individual amino acids and therefore can be called an amino acid response element (AARE). In addition, we show that the CHOP AARE is related to C/EBP and ATF/CRE binding sites and binds in vitro the activating transcription factor 2 (ATF-2) in starved and unstarved conditions. Using ATF-2-deficient mouse embryonic fibroblasts and an ATF-2-dominant negative mutant, we demonstrate that expression of this transcription factor is essential for the transcriptional activation of CHOP by leucine starvation. Altogether, these results suggest that ATF-2 may be a member of a cascade of molecular events by which the cellular concentration of amino acids can regulate mammalian gene expression.