Young E T, Saario J, Kacherovsky N, Chao A, Sloan J S, Dombek K M
Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350, USA.
J Biol Chem. 1998 Nov 27;273(48):32080-7. doi: 10.1074/jbc.273.48.32080.
The yeast transcriptional activator Adr1p controls expression of the glucose-repressible alcohol dehydrogenase gene (ADH2), genes involved in glycerol metabolism, and genes required for peroxisome biogenesis and function. Previous data suggested that promoter-specific activation domains might contribute to expression of the different types of ADR1-dependent genes. By using gene fusions encoding the Gal4p DNA binding domain and portions of Adr1p, we identified a single, strong acidic activation domain spanning amino acids 420-462 of Adr1p. Both acidic and hydrophobic amino acids within this activation domain were important for its function. The critical hydrophobic residues are in a motif previously identified in p53 and related acidic activators. A mini-Adr1 protein consisting of the DNA binding domain of Adr1p fused to this 42-residue activation domain carried out all of the known functions of wild-type ADR1. It conferred stringent glucose repression on the ADH2 locus and on UAS1-containing reporter genes. The putative inhibitory region of Adr1p encompassing the protein kinase A phosphorylation site at Ser-230 is thus not essential for glucose repression mediated by ADR1. Mini-ADR1 allowed efficient derepression of gene expression. In addition it complemented an ADR1-null allele for growth on glycerol and oleate media, indicating efficient activation of genes required for glycerol metabolism and peroxisome biogenesis. Thus, a single activation domain can activate all ADR1-dependent promoters.
酵母转录激活因子Adr1p可调控葡萄糖可阻遏的乙醇脱氢酶基因（ADH2）、参与甘油代谢的基因以及过氧化物酶体生物发生和功能所需基因的表达。先前的数据表明，启动子特异性激活结构域可能有助于不同类型的ADR1依赖性基因的表达。通过使用编码Gal4p DNA结合结构域和Adr1p部分片段的基因融合体，我们鉴定出一个单一的、强大的酸性激活结构域，其跨度为Adr1p的420 - 462位氨基酸。该激活结构域内的酸性和疏水性氨基酸对其功能都很重要。关键的疏水性残基存在于先前在p53和相关酸性激活因子中鉴定出的基序中。一种由Adr1p的DNA结合结构域与这个42个残基的激活结构域融合而成的微型Adr1蛋白，执行了野生型ADR1的所有已知功能。它对ADH2基因座和含UAS1的报告基因施加了严格的葡萄糖阻遏作用。因此，Adr1p包含Ser - 230处蛋白激酶A磷酸化位点的假定抑制区域，对于ADR1介导的葡萄糖阻遏并非必需。微型ADR1允许基因表达的有效去阻遏。此外，它在甘油和油酸培养基上生长时可互补ADR1缺失等位基因，表明其能有效激活甘油代谢和过氧化物酶体生物发生所需的基因。因此，一个单一的激活结构域可以激活所有ADR1依赖性启动子。
