Regulation of yeast COX6 by the general transcription factor ABF1 and separate HAP2- and heme-responsive elements.
Regulation of yeast COX6 by the general transcription factor ABF1 and separate HAP2- and heme-responsive elements.
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通用转录因子 ABF1 和单独的 HAP2 和血红素响应元件对酵母 COX6 的调节。
DOI：
10.1128/mcb.12.5.2302-2314.1992
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发表时间：
1992
影响因子：
5.3
通讯作者：
Poyton,RO
中科院分区：
文献类型：
--
作者：
Trawick,JD;Kraut,N;Simon,FR;Poyton,RO
酿酒酵母COX6基因的转录受血红素和碳源的调控。它还受到HAP2/3/4转录因子复合体以及SNF1和SSN6的影响。此前，我们已经证明，这种调节大部分是通过COX6启动子上游84个碱基的激活片段UAS6介导的。在这项研究中，通过接头扫描突变和蛋白质结合分析，我们已经确定了UAS6中的三个元件及其下游的一个元件是重要的。其中两个，HDS1(依赖于血红素的位点1，在-269到-251bp之间)和HDS2(在-228到-220bp之间)，介导了血红素对COX6的调节。两者都起到了负面作用。结构域2(在-279和-269bp之间)和结构域1(在-302和-281bp之间)起正作用。结构域2是在抑制而不是去抑制碳源中生长的细胞中最佳转录所必需的。结构域1对于生长在抑制碳源上的细胞本身的转录是必不可少的，是在减压碳源生长的细胞中实现最佳转录所必需的，是足够的葡萄糖抑制-去阻遏，并且是HAP2影响COX6转录的UAS6元件。该元件包含UAS6内的主要蛋白质结合位点。它具有ABF1和HAP2的共同结合序列。凝胶迁移率移动实验表明，结构域1与ABF1结合，并在抑制或去抑制碳源生长的细胞提取物中形成不同数量的DNA-蛋白质复合体。相反，凝胶迁移率改变实验未能揭示HAP2或HAP3与结构域1结合，或者HAP3突变影响与其结合的复合体。综上所述，这些发现支持以下结论：COX6转录受到正向和负向调控；血红素和碳源通过不同的位点发挥作用；结构域1在转录抑制碳源方面是绝对必要的；ABF1是COX6转录调控的主要成分；HAP2/3/4复合体最可能间接影响COX6转录。
Transcription of theSaccharomyces cerevisiae COX6gene is regulated by heme and carbon source. It is also affected by the HAP2/3/4 transcription factor complex and bySNF1andSSN6.Previously, we have shown that most of this regulation is mediated through UAS6, an 84-bp upstream activation segment of theCOX6promoter. In this study, by using linker scanning mutagenesis and protein binding assays, we have identified three elements within UAS6and one element downstream of it that are important. Two of these, HDS1 (heme-dependent site 1; between -269 and -251 bp) and HDS2 (between -228 and -220 bp), mediate regulation ofCOX6by heme. Both act negatively. The other two elements, domain 2 (between -279 and -269 bp) and domain 1 (between —302 and —281 bp), act positively. Domain 2 is required for optimal transcription in cells grown in repressing but not derepressing carbon sources. Domain 1 is essential for transcription per se in cells grown on repressing carbon sources, is required for optimal transcription in cells grown on a derepressing carbon source, is sufficient for glucose repression-derepression, and is the element of UAS6at which HAP2 affectsCOX6transcription. This element contains the major protein binding sites within UAS6. It has consensus binding sequences for ABF1 and HAP2. Gel mobility shift experiments show that domain 1 binds ABF1 and forms different numbers of DNA-protein complexes in extracts from cells grown in repressing or derepressing carbon sources. In contrast, gel mobility shift experiments have failed to reveal that HAP2 or HAP3 binds to domain 1 or thathap3mutations affect the complexes bound to it. Together, these findings permit the following conclusions:COX6transcription is regulated both positively and negatively; heme and carbon source exert their effects through different sites; domain 1 is absolutely essential for transcription on repressing carbon sources; ABF1 is a major component in the regulation ofCOX6transcription; and the HAP2/3/4 complex most likely affectsCOX6transcription indirectly.