The LsrR gene is located upstream of the LsrACDBFG operon, and the transcriptional transfer promoter LsrA is adjacent to the LsrR promoter. The promoter regions of these two genes can be blocked by Lsrr protein, so they are not expressed in normal condition. Only when the signal molecule AI-2 exists can it bind to Lsrr and change its conformation so that gene expression is no longer suppressed and can function normally. Therefore, the promoter region of LSRA gene is released in the presence of signaling molecules to regulate and express the gene.
LsrA promoter, as an important component of negative regulation of LLDR in the whole system, has been proved to work properly. In the absence of AI2, LLDR binding was not open.While in the case of AI2 existence , gene expression was initiated.
As the following figures show, when lldPRD operon promoter-LuxS works with LsrA-GFP and lldPRD operon promoter-LuxS-Lldr with LsrA-GFP, the QS system can be activated in the presence of lactic acid,which means that the LsrA promoter can work properly in the system (Figure 1,Figure 2)
Figure 1:lldPRD operon promoter-LuxS work with LsrA-GFP
Figure 2:lldPRD promoter-LuxS-Lldr w
Sequence and Features
- 10COMPATIBLE WITH RFC
- 12COMPATIBLE WITH RFC
- 21COMPATIBLE WITH RFC
- 23COMPATIBLE WITH RFC
- 25COMPATIBLE WITH RFC
- 1000COMPATIBLE WITH RFC