Carmen A A, Brindle P K, Park C S, Holland M J
Department of Biological Chemistry, School of Medicine, University of California, Davis 95616, USA.
Yeast. 1995 Sep 15;11(11):1031-43. doi: 10.1002/yea.320111105.
The activity of an upstream repression sequence (URS element) that mediates a 20-fold repression of ENO1 expression in cells grown in a medium containing glucose was characterized. Sequences that are sufficient for orientation-dependent ENO1 URS element activity were mapped between positions -241 and -126 relative to the ENO1 transcriptional initiation site. The ENO1 URS element repressed transcription of the yeast CYC1 gene when positioned between the CYC1 upstream activation sequences (UAS elements) and TATAAA boxes. The ENO1 URS element failed to repress transcription of the wild-type yeast enolase gene ENO2; however, expression of an ENO2 gene lacking one of the ENO2 UAS elements was efficiently repressed by the ENO1 URS element, suggesting that the URS element interferes with the transcriptional activation by some, but not all, UAS elements. In contrast to the ENO1 gene, the ENO1 URS element repressed CYC1 and ENO2 expression in cells grown on glucose or glycerol plus lactate. Evidence is presented that the ENO1 URS element also functions during stationary growth phase.
对一个上游阻遏序列（URS元件）的活性进行了表征，该元件在含葡萄糖的培养基中生长的细胞中介导对ENO1表达20倍的阻遏作用。相对于ENO1转录起始位点，足以实现依赖方向的ENO1 URS元件活性的序列被定位在-241至-126位之间。当位于酵母CYC1基因的上游激活序列（UAS元件）和TATAAA框之间时，ENO1 URS元件可抑制酵母CYC1基因的转录。ENO1 URS元件无法抑制野生型酵母烯醇化酶基因ENO2的转录；然而，缺少一个ENO2 UAS元件的ENO2基因的表达可被ENO1 URS元件有效抑制，这表明URS元件会干扰部分但并非全部UAS元件的转录激活作用。与ENO1基因不同，ENO1 URS元件在以葡萄糖或甘油加乳酸为培养基生长的细胞中可抑制CYC1和ENO2的表达。有证据表明，ENO1 URS元件在稳定生长期也发挥作用。
