de Winde J H, Grivell L A
Department of Molecular Cell Biology, University of Amsterdam, The Netherlands.
Mol Cell Biol. 1992 Jun;12(6):2872-83. doi: 10.1128/mcb.12.6.2872-2883.1992.
The multifunctional DNA-binding proteins ABF1 and CPF1 bind in a mutually exclusive manner to the promoter region of the QCR8 gene, which encodes 11-kDa subunit VIII of the Saccharomyces cerevisiae mitochondrial ubiquinol-cytochrome c oxidoreductase (QCR). We investigated the roles that the two factors play in transcriptional regulation of this gene. To this end, the overlapping binding sites for ABF1 and CPF1 were mutated and placed in the chromosomal context of the QCR8 promoter. The effects on transcription of the QCR8 gene were analyzed both under steady-state conditions and during nutritional shifts. We found that ABF1 is required for repressed and derepressed transcription levels and for efficient induction of transcription upon escape from catabolite repression, independently of DNA replication. CPF1 acts as a negative regulator, modulating the overall induction response. Alleviation of repression through CPF1 requires passage through the S phase. Implications of these findings for the roles played by ABF1 and CPF1 in global regulation of mitochondrial biogenesis are discussed.
多功能DNA结合蛋白ABF1和CPF1以互斥的方式结合到QCR8基因的启动子区域，该基因编码酿酒酵母线粒体泛醇-细胞色素c氧化还原酶（QCR）的11-kDa亚基VIII。我们研究了这两个因子在该基因转录调控中所起的作用。为此，ABF1和CPF1的重叠结合位点被突变，并置于QCR8启动子的染色体背景中。在稳态条件下和营养转换期间，分析了对QCR8基因转录的影响。我们发现，ABF1是抑制和去抑制转录水平以及从分解代谢物阻遏中逃逸时有效诱导转录所必需的，与DNA复制无关。CPF1作为负调节因子，调节整体诱导反应。通过CPF1缓解阻遏需要经历S期。讨论了这些发现对ABF1和CPF1在线粒体生物发生全局调控中所起作用的意义。
