Transcriptional remodeling in response to iron deprivation in Saccharomyces cerevisiae
Transcriptional remodeling in response to iron deprivation in Saccharomyces cerevisiae
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DOI：
10.1091/mbc.e03-09-0642
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发表时间：
2004-03-01
影响因子：
3.3
通讯作者：
Philpott, CC
中科院分区：
文献类型：
--
作者：
Shakoury-Elizeh, M;Tiedeman, J;Philpott, CC
芽殖酵母酿酒酵母通过激活主要的铁依赖性转录因子Aft1p和参与铁摄取的转录系统来响应环境中铁的耗尽。在这里，我们研究了铁剥夺的转录反应，并确定了新的Aft1p靶基因。我们发现，其他代谢途径的铁调节：生物素的吸收和生物合成，氮同化，嘌呤生物合成。在这些途径中活跃的两种酶，生物素合酶和谷氨酸合酶，需要铁硫簇的活性。缺铁激活生物素输入者的转录，同时抑制整个生物素生物合成途径的转录。缺铁诱导了参与氮同化和氨基酸代谢的多个基因，而氮同化的关键酶谷氨酸合成酶则受到抑制。谷氨酸合酶启动子内的CGG回文结构赋予铁调控的表达，表明由双核锌簇家族的转录因子控制。我们提供的证据表明，酵母铁剥夺进行转录重塑，导致从铁依赖的平行，但不依赖铁，代谢途径的转变。
The budding yeast Saccharomyces cerevisiae responds to depletion of iron in the environment by activating Aft1p, the major iron-dependent transcription factor, and by transcribing systems involved in the uptake of iron. Here, we have studied the transcriptional response to iron deprivation and have identified new Aft1p target genes. We find that other metabolic pathways are regulated by iron: biotin uptake and biosynthesis, nitrogen assimilation, and purine biosynthesis. Two enzymes active in these pathways, biotin synthase and glutamate synthase, require an iron-sulfur cluster for activity. Iron deprivation activates transcription of the biotin importer and simultaneously represses transcription of the entire biotin biosynthetic pathway. Multiple genes involved in nitrogen assimilation and amino acid metabolism are induced by iron deprivation, whereas glutamate synthase, a key enzyme in nitrogen assimilation, is repressed. A CGG palindrome within the promoter of glutamate synthase confers iron-regulated expression, suggesting control by a transcription factor of the binuclear zinc cluster family. We provide evidence that yeast subjected to iron deprivation undergo a transcriptional remodeling, resulting in a shift from iron-dependent to parallel, but iron-independent, metabolic pathways.