Poon P P, Storms R K
Department of Biology, Concordia University, Montreal, Quebec, Canada.
J Biol Chem. 1991 Sep 5;266(25):16808-12.
The rate of transcription of the Saccharomyces cerevisiae gene encoding thymidylate synthase (TMP1) fluctuates periodically during the cell cycle. The simplest explanation for this pattern of expression is that transcription occurs during the late G1 and early S phases and does not occur during other stages of the cell cycle. In this report, however, we show that TMP1 is subject to regulation that results in at least three different levels of expression: essentially nondetectable expression during stationary phase (G0), moderate level expression in START-arrested growing cells (START-independent), and a high level of expression in proliferating cells (START-dependent). Our analysis also shows that upstream elements important for START-independent expression and required for START-dependent expression are located within a 37-base region.
酿酒酵母中编码胸苷酸合成酶（TMP1）的基因转录速率在细胞周期中呈周期性波动。对于这种表达模式最简单的解释是，转录发生在G1晚期和S期早期，而在细胞周期的其他阶段不发生。然而，在本报告中，我们表明TMP1受到调控，导致至少三种不同水平的表达：静止期（G0）基本检测不到表达，处于START阻滞的生长细胞中表达水平中等（不依赖START），而在增殖细胞中表达水平高（依赖START）。我们的分析还表明，对不依赖START的表达很重要且是依赖START的表达所必需的上游元件位于一个37个碱基的区域内。
