Sancar G B, Ferris R, Smith F W, Vandeberg B
Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill 27599-7260, USA.
Nucleic Acids Res. 1995 Nov 11;23(21):4320-8. doi: 10.1093/nar/23.21.4320.
The PHR1 gene of Saccharomyces cerevisiae encodes the apoenzyme for the DNA repair enzyme photolyase. PHR1 transcription is induced in response to 254 nm radiation and a variety of chemical damaging agents. We report here the identification of promoter elements required for PHR1 expression. Transcription is regulated primarily through three sequence elements clustered within a 120 bp region immediately upstream of the translational start site. A 20 bp interrupted palindrome comprises UASPHR1 and is responsible for 80-90% of basal and induced expression. UASPHR1 alone can activate transcription of a CYC1 minimal promoter but does not confer damage responsiveness. In the intact PHR1 promoter UAS function is dependent upon an upstream essential sequence (UES). URSPHR1 contains a binding site for the damage-responsive repressor Prp; consistent with this role, deletion or specific mutations of the URS increase basal level expression and decrease the induction ratio. Deletion of URSPHR1 also eliminates the requirement for UESPHR1 for promoter activation, indicating that the UES attenuates Prp-mediated repression. Sequences within UASPHR1 are similar to regulatory sequences found upstream of both damage responsive and nonresponsive genes involved in DNA repair and metabolism.
酿酒酵母的PHR1基因编码DNA修复酶光裂合酶的脱辅基酶。PHR1转录是在对254nm辐射和多种化学损伤剂作出反应时被诱导的。我们在此报告对PHR1表达所需启动子元件的鉴定。转录主要通过聚集在翻译起始位点上游120bp区域内的三个序列元件进行调控。一个20bp的间断回文结构构成了UASPHR1，并负责80 - 90%的基础表达和诱导表达。单独的UASPHR1可以激活CYC1最小启动子的转录，但不赋予损伤反应性。在完整的PHR1启动子中，UAS功能依赖于上游必需序列（UES）。URSPHR1包含损伤反应性阻遏物Prp的结合位点；与此作用一致，URS的缺失或特定突变会增加基础水平表达并降低诱导率。URSPHR1的缺失也消除了启动子激活对UESPHR1的需求，表明UES减弱了Prp介导的阻遏作用。UASPHR1内的序列与在参与DNA修复和代谢的损伤反应性和非反应性基因上游发现的调控序列相似。
