Role of the purine repressor in the regulation of pyrimidine gene expression in Escherichia coli K-12.
Role of the purine repressor in the regulation of pyrimidine gene expression in Escherichia coli K-12.
复制标题
嘌呤阻遏物在大肠杆菌 K-12 嘧啶基因表达调节中的作用。
DOI：
10.1128/jb.172.6.3208-3213.1990
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发表时间：
1990
影响因子：
3.2
通讯作者：
TurnboughJr,CL
中科院分区：
文献类型：
--
作者：
Wilson,HR;TurnboughJr,CL
The pyrC and pyrD genes of Escherichia coli K-12 encode the pyrimidine biosynthetic enzymes dihydroorotase and dihydroorotate dehydrogenase, respectively. A highly conserved sequence in the promoter regions of these two genes is similar to the pur operator, which is the binding site for the purine repressor (PurR). In this study, we examined the role of PurR in the regulation of pyrC and pyrD expression. Our results show that pyrC and pyrD expression was repressed approximately twofold in cells grown in the presence of adenine [corrected] through a mechanism requiring PurR. A mutation, designated pyrCp926, which alters a 6-base-pair region within the conserved sequence in the pyrC promoter eliminated PurR-mediated repression of pyrC expression. This result indicates that PurR binds to the pyrC (and presumably to the pyrD) conserved sequence and inhibits transcriptional initiation. We also demonstrated that the pyrCp926 mutation had no effect on pyrimidine-mediated regulation of pyrC expression, indicating that pyrimidine and purine effectors act through independent mechanisms to control the expression of the pyrC and pyrD genes.
