Wanke C, Eckert S, Albrecht G, van Hartingsveldt W, Punt P J, van den Hondel C A, Braus G H
Institute for Biochemistry, Microbiology, and Genetics, Friedrich Alexander University, Erlangen, Germany.
Mol Microbiol. 1997 Jan;23(1):23-33. doi: 10.1046/j.1365-2958.1997.1741549.x.
The general control transcriptional regulator gene cpcA of Aspergillus niger was cloned by complementation of a Saccharomyces cerevisiae delta gcn4 mutant strain. The encoded protein conferred resistance to amino acid analogues when expressed in yeast. Disruption of cpcA in A. niger resulted in a strain which is sensitive towards 3-aminotriazole and fails to respond to amino acid starvation, cpcA encodes a transcript of approximately 2400 nucleotides in length that includes a 5' leader region of 900 nucleotides. The 5' leader region contains two small open reading frames, suggesting translational control of gene expression. Steady-state mRNA levels of cpcA increase by a factor of three upon amino acid starvation. The coding region of cpcA is interrupted by a 57 bp intron and the deduced amino acid sequence displays an approximately 30% overall identity to yeast GCN4p and Neurospora crassa cpc1p. Critical amino acid residues of the transcriptional activation domains of GCN4p are conserved in cpcAp. The basic DNA-binding domain shows up to 70% amino acid sequence identity to other basic zipper (bZIP)-type transcriptional activators. cpcAp binds specifically to a GCN4p recognition element in gel retardation experiments. The C-terminal dimerization domain encodes a leucine zipper with only a single leucine residue.
通过对酿酒酵母Δgcn4突变菌株进行互补，克隆了黑曲霉的一般控制转录调节基因cpcA。当在酵母中表达时，编码的蛋白质赋予对氨基酸类似物的抗性。黑曲霉中cpcA的破坏导致一个菌株对3-氨基三唑敏感，并且对氨基酸饥饿没有反应。cpcA编码一个长度约为2400个核苷酸的转录本，其中包括一个900个核苷酸的5'前导区。5'前导区包含两个小的开放阅读框，表明基因表达的翻译控制。在氨基酸饥饿时，cpcA的稳态mRNA水平增加三倍。cpcA的编码区被一个57 bp的内含子打断，推导的氨基酸序列与酵母GCN4p和粗糙脉孢菌cpc1p总体上有大约30%的同一性。GCN4p转录激活域的关键氨基酸残基在cpcAp中是保守的。基本DNA结合域与其他基本拉链（bZIP）型转录激活剂的氨基酸序列同一性高达70%。在凝胶阻滞实验中，cpcAp特异性结合GCN4p识别元件。C端二聚化域编码一个只有单个亮氨酸残基的亮氨酸拉链。
