Mutations in PurBox1 of the Bacillus subtilis pur operon control site affect adenine-regulated expression in vivo  

作　　者：Howard Zalkin 

机构地区：[1]Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA

出　　处：《Science China(Life Sciences)》2005年第2期133-138,共6页中国科学（生命科学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.30070419).

摘　　要：Transcription of the Bacillus subtilis pur operon is regulated by a purine repressor (PurR)-DNA control site interaction. The pur operon control site has two PurBoxes that are re- quired for high-affinity PurR binding. An upstream, strong-binding PurBox1 is at position –81 to –68 relative to the transcription start site and a downstream weak-binding PurBox2 is at position –49 to –36. We constructed three PurBox1 mutations and the effects on binding of PurR to the control region in vitro and on regulation of pur operon expression in vivo were investigated. The mutations significantly reduced the binding of PurR to control region DNA. In strains with G-75A, G-75T and a five bp deletion (?5) pur operon repression was defective in vivo. In addition in vivo PurR titration was used to confirm that sequences flanking PurBox1 and PurBox2 are re- quired for PurR binding to the pur operon control site.Transcription of the Bacillus subtilis pur operon is regulated by a purine repressor (PurR)-DNA control site interaction. The pur operon control site has two PurBoxes that are re- quired for high-affinity PurR binding. An upstream, strong-binding PurBox1 is at position –81 to –68 relative to the transcription start site and a downstream weak-binding PurBox2 is at position –49 to –36. We constructed three PurBox1 mutations and the effects on binding of PurR to the control region in vitro and on regulation of pur operon expression in vivo were investigated. The mutations significantly reduced the binding of PurR to control region DNA. In strains with G-75A, G-75T and a five bp deletion (?5) pur operon repression was defective in vivo. In addition in vivo PurR titration was used to confirm that sequences flanking PurBox1 and PurBox2 are re- quired for PurR binding to the pur operon control site.

关 键 词：Bacillus subtilis  PUR operon  PURINE REPRESSOR (PurR)  ADENINE regulation  mutation. 

分 类 号：Q78[生物学—分子生物学]