Albrecht G, Mösch H U, Hoffmann B, Reusser U, Braus G H
Institut für Mikrobiologie und Genetik, Abteilung für Molekulare Mikrobiologie, Georg-August-Universität, Grisebachstrasse 8, D-37077 Göttingen, Germany.
J Biol Chem. 1998 May 22;273(21):12696-702. doi: 10.1074/jbc.273.21.12696.
In Saccharomyces cerevisiae the GCN4 gene encodes the transcriptional activator of the "general control" system of amino acid bioynthesis, a network of at least 12 different biosynthetic pathways. We characterized the consequences of the general control response upon the signal "amino acid starvation" induced by the histidine analogue 3-aminotriazole with respect to Gcn4p levels in more detail. Therefore, we established test systems to monitor the time course of different parameters, including GCN4 mRNA, Gcn4 protein, Gcn4p DNA binding activity, as well as Gcn4p transactivation ability. We observed a biphasic response of Gcn4p activity in the cell. At first, translation of GCN4 mRNA is induced within 20 min after switch to starvation conditions. However, an additional increase in GCN4 transcript steady state level was observed, leading to an additional second phase of GCN4 expression after 3-4 h of starvation. The DNA binding activity of Gcn4p, as well as the ability to activate transcription of target genes, correlate with the amount of Gcn4 protein in the cell, suggesting that under the tested conditions there is no additional regulation of DNA binding or transactivation ability of Gcn4p, respectively.
在酿酒酵母中，GCN4基因编码氨基酸生物合成“全局调控”系统的转录激活因子，该系统是一个由至少12种不同生物合成途径组成的网络。我们更详细地研究了由组氨酸类似物3-氨基三唑诱导的“氨基酸饥饿”信号引发的全局调控反应对Gcn4p水平的影响。因此，我们建立了测试系统来监测不同参数的时间进程，包括GCN4 mRNA、Gcn4蛋白、Gcn4p与DNA的结合活性以及Gcn4p的反式激活能力。我们观察到细胞中Gcn4p活性呈现双相反应。首先，在切换到饥饿条件后20分钟内，GCN4 mRNA的翻译被诱导。然而，我们还观察到GCN4转录本稳态水平进一步升高，导致在饥饿3-4小时后出现GCN4表达的第二个阶段。Gcn4p与DNA的结合活性以及激活靶基因转录的能力与细胞中Gcn4蛋白的量相关，这表明在所测试的条件下，Gcn4p与DNA的结合或反式激活能力没有额外的调控。
