DISTINCTLY REGULATED TANDEM UPSTREAM ACTIVATION SITES MEDIATE CATABOLITE REPRESSION OF THE CYC1 GENE OF S-CEREVISIAE
DISTINCTLY REGULATED TANDEM UPSTREAM ACTIVATION SITES MEDIATE CATABOLITE REPRESSION OF THE CYC1 GENE OF S-CEREVISIAE
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DOI：
10.1016/0092-8674(84)90243-5
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发表时间：
1984-01-01
期刊：
影响因子：
64.5
通讯作者：
ALANI, E
中科院分区：
文献类型：
--
作者：
GUARENTE, L;LALONDE, B;ALANI, E
酵母菌Cyc1基因上游激活位点(UAS)含有两个同源亚基：UAS1和UAS2。当每个位置位于酵母LEU2基因转录起始区的上游时，激活由分解代谢抑制调节的LEU2转录。在葡萄糖抑制条件下，UAS1负责大部分转录，而UAS1和UAS2对乳酸去抑制转录起同等作用。UAS2的单点突变使其在葡萄糖中的活性增加10到20倍。多项实验表明，UAS1和UAS2在分子水平上受到明显的调控。首先，通过增加细胞内的血红素水平，UAS1而不是UAS2在葡萄糖中完全被抑制。第二，反式调节突变hap1-1和hap2-1选择性地取消UAS1或UAS2的活性。HAP1似乎编码一种蛋白质，通过对细胞内血红素水平的反应来调节UAS1的分解代谢抑制。
The upstream activation site (UAS) of the yeast CYC1 gene is shown to contain 2 homologous subsites, UAS1 and UAS2. Each site, when placed upstream of the transcriptional initiation region of the yeast LEU2 gene, activates LEU2 transcription which is regulated by catabolite repression. UAS1 is responsible for most of the transcription under glucose repressed conditions, while UAS1 and UAS2 contribute equally to lactate derepressed transcription. A single point mutation in UAS2 increases its activity in glucose 10- to 20-fold. Several experiments indicate that UAS1 and UAS2 are regulated distinctly at the molecular level. First, UAS1 but not UAS2 is fully depressed in glucose by increasing the levels of intracellular heme. Second, trans-acting regulatory mutations, hap1-1 and hap2-1, selectively abolish the activity of UAS1 or UAS2. HAP1 appears to encode a protein that mediates catabolite repression of UAS1 by responding to intracellular heme levels.