Farnham P J, Schimke R T
J Biol Chem. 1985 Jun 25;260(12):7675-80.
We have studied transcription of the dihydrofolate reductase gene as cells progress through the cell cycle. We used the techniques of DNA-excess filter hybridization and in vivo pulse labeling of a synchronous population of cells to measure the transcription rate of the dihydrofolate reductase gene in different phases of the cell cycle. Our results indicate that the dihydrofolate reductase gene is cell cycle regulated at the transcriptional level. The transcription rate is low in G1, increases 7-fold at the beginning of S phase, decreases almost immediately thereafter, and remains low throughout the remainder of S and into G2. This cell cycle regulation seen in the G1 to S phase transition is achieved by increasing the rate of transcription from a single promoter region. The fact that this region is similar to promoter regions of other housekeeping genes suggests that this type of regulation may not be unique to dihydrofolate reductase.
我们研究了细胞在整个细胞周期进程中，二氢叶酸还原酶基因的转录情况。我们运用了DNA过量滤膜杂交技术以及对同步化细胞群体进行体内脉冲标记的方法，来测定细胞周期不同阶段中二氢叶酸还原酶基因的转录速率。我们的研究结果表明，二氢叶酸还原酶基因在转录水平受到细胞周期调控。在G1期转录速率较低，在S期开始时增加7倍，此后几乎立即下降，并在S期剩余时间以及进入G2期后一直保持较低水平。在G1期到S期转变过程中观察到的这种细胞周期调控，是通过提高单个启动子区域的转录速率来实现的。该区域与其他管家基因的启动子区域相似，这一事实表明这种调控类型可能并非二氢叶酸还原酶所特有。
