In order to investigate the role of DNA bending on the regulation of σ54-dependent promot- ers, we introduced the CopG binding site between the enhancer-like element and the core promoter of glnAp2, nifLp and glnHp2,...In order to investigate the role of DNA bending on the regulation of σ54-dependent promot- ers, we introduced the CopG binding site between the enhancer-like element and the core promoter of glnAp2, nifLp and glnHp2, without changing the dis- tance in between. The expression activities of these homologous promoters were either activated or re- pressed by the CopG-induced DNA bending in E. coli. In this case, similar regulatory pattern (either acti- vated or repressed) could be observed, when the bending centers from CopG are in integral DNA he- lixes interval, while opposite regulatory pattern could be observed, when the bending centers from CopG are in integral plus a half DNA helixes interval. These results suggested that CopG-induced DNA bending can exert regulatory effects on the transcription of σ54-dependent promoters probably by altering the relative DNA helix phase of 54 RNA polymerase and NtrC.展开更多
基金supported in part by the National Basic Research Program of China(Grant No.2001CB 108903)National Natural Science Foundation of China(Grants No.39925017&30200047).
文摘In order to investigate the role of DNA bending on the regulation of σ54-dependent promot- ers, we introduced the CopG binding site between the enhancer-like element and the core promoter of glnAp2, nifLp and glnHp2, without changing the dis- tance in between. The expression activities of these homologous promoters were either activated or re- pressed by the CopG-induced DNA bending in E. coli. In this case, similar regulatory pattern (either acti- vated or repressed) could be observed, when the bending centers from CopG are in integral DNA he- lixes interval, while opposite regulatory pattern could be observed, when the bending centers from CopG are in integral plus a half DNA helixes interval. These results suggested that CopG-induced DNA bending can exert regulatory effects on the transcription of σ54-dependent promoters probably by altering the relative DNA helix phase of 54 RNA polymerase and NtrC.
