The transcriptional response of the yeast Na+-ATPase ENA1 gene to alkaline stress involves three main signaling pathways
The transcriptional response of the yeast Na+-ATPase ENA1 gene to alkaline stress involves three main signaling pathways
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DOI：
10.1074/jbc.m606483200
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发表时间：
2006-12-01
影响因子：
4.8
通讯作者：
Arino, Joaquin
中科院分区：
文献类型：
--
作者：
Platara, Maria;Ruiz, Amparo;Arino, Joaquin
酿酒酵母对环境碱化的适应性反应导致基因表达的重塑。一个关键的目标是基因ENA 1，编码Na+ ATP酶，其碱性pH诱导已被证明涉及钙调神经磷酸酶和Rim 101/Nrg 1途径。先前对ENA 1启动子的功能分析揭示了钙调神经磷酸酶非依赖性pH响应区（ARR 2，83个核苷酸）。我们在此将这种反应限制在一个小的（42个核苷酸）ARR 2 5 '-区域，称为MCIR（最小钙调磷酸酶独立反应），其中包含一个能够结合Mig 1，2阻遏物的β元件。高pH值诱导的响应驱动从这个区域在很大程度上取消snf 1细胞和适度减少rim 101菌株。缺乏Mig 1或Mig 2阻遏物的细胞具有接近野生型的反应，但双突变体在碱性胁迫下呈现高水平的表达。NRG 1的缺失（而非NRG 2）导致表达增加。从MCIR区域的诱导是边际的四重突变体缺乏NRG 1，2和Mig 1，2阻遏物。体外带移实验证明Nrg 1与ARR 2区域的5'末端结合。此外，我们表明，Nrg 1结合在体内周围的MCIR区域在标准的生长条件下，结合在很大程度上取消后，高pH值的压力。因此，ENA 1基因的非钙调神经磷酸酶依赖性反应受Rim 101（通过Nrg 1）和Snf 1（通过Nrg 1和Mig 2）的调节。因此，在钙调磷酸酶抑制剂FK 506存在下，在snf 1 rim 101突变体中通过碱胁迫对整个ENA 1启动子的诱导被完全消除。因此，ENA 1基因对碱性胁迫的转录响应整合了三种不同的信号通路。
Adaptive response of the yeast Saccharomyces cerevisiae to environmental alkalinization results in remodeling of gene expression. A key target is the gene ENA1, encoding a Na+ ATPase, whose induction by alkaline pH has been shown to involve calcineurin and the Rim101/Nrg1 pathway. Previous functional analysis of the ENA1 promoter revealed a calcineurin-independent pH responsive region (ARR2, 83 nucleotides). We restrict here this response to a small (42 nucleotides) ARR2 5'-region, named MCIR (minimum calcineurin independent response), which contains a MIG element, able to bind Mig1,2 repressors. High pH-induced response driven from this region was largely abolished in snf1 cells and moderately reduced in a rim101 strain. Cells lacking Mig1 or Mig2 repressors had a near wild type response, but the double mutant presented a high level of expression upon alkaline stress. Deletion of NRG1 (but not of NRG2) resulted in increased expression. Induction from the MCIR region was marginal in a quadruple mutant lacking Nrg1,2 and Mig1,2 repressors. In vitro band shift experiments demonstrated binding of Nrg1 to the 5' end of the ARR2 region. Furthermore, we show that Nrg1 binds in vivo around the MCIR region under standard growth conditions, and that binding is largely abolished after high pH stress. Therefore, the calcineurin-independent response of the ENA1 gene is under the regulation of Rim101 (through Nrg1) and Snf1 (through Nrg1 and Mig2). Accordingly, induction by alkaline stress of the entire ENA1 promoter in a snf1 rim101 mutant in the presence of the calcineurin inhibitor FK506 is completely abolished. Thus, the transcriptional response to alkaline stress of the ENA1 gene integrates three different signaling pathways.