Nikawa J, Hosaka K
Department of Biochemical Engineering and Science, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka, Japan.
Mol Microbiol. 1995 Apr;16(2):301-8. doi: 10.1111/j.1365-2958.1995.tb02302.x.
The expression of many genes of Saccharomyces cerevisiae, such as ITR1, is regulated by inositol and choline. In this work, a yeast strain has been constructed in which HIS3 expression is controlled by the ITR1 promoter. Using this strain, three genes were isolated which, when introduced as multicopies, abolish the repression caused by inositol via the ITR1 promoter. Northern blot analysis revealed that two of these three genes, designated as DIE1 and DIE2, clearly increased the expression of ITR1. DIE2 is more effective for ITR1 expression than DIE1. Gene-disruption experiments revealed that DIE1 was essential for the expression of ITR1 but that DIE2 was not. The sequence of the DIE1 gene was shown to be identical to that of INO2 (also called SCS1), which encodes a protein required for the expression of INO1. DIE2 is a new gene and is capable of encoding 525 amino acid residues with a calculated molecular weight of 61,789. Experiments involving lacZ fusion genes showed that multicopy DIE2 resulted in an increase in the expression of both ITR1 and INO1. These results strongly suggest that the DIE1 and DIE2 gene products have an important regulatory function for gene expression of not only ITR1 but also INO1.
酿酒酵母的许多基因，如ITR1的表达受肌醇和胆碱的调控。在本研究中，构建了一种酵母菌株，其中HIS3的表达受ITR1启动子的控制。利用该菌株，分离出三个基因，当以多拷贝形式导入时，它们可消除肌醇通过ITR1启动子引起的抑制作用。Northern印迹分析表明，这三个基因中的两个，命名为DIE1和DIE2，明显增加了ITR1的表达。DIE2对ITR1表达的作用比DIE1更有效。基因破坏实验表明，DIE1对ITR1的表达至关重要，而DIE2并非如此。结果显示，DIE1基因的序列与INO2（也称为SCS1）相同，INO2编码INO1表达所需的一种蛋白质。DIE2是一个新基因，能够编码525个氨基酸残基，计算分子量为61789。涉及lacZ融合基因的实验表明，多拷贝的DIE2导致ITR1和INO1的表达均增加。这些结果强烈表明，DIE1和DIE2基因产物不仅对ITR1而且对INO1的基因表达具有重要的调控功能。
