Lac repressor (LacR) and operator sequences (O1 and O2) is part of the lactose operon derived from Lactobacillus delbrueckii.When the external pH value declines to 5.5, rcfB promoter will be highly upregulated. Along with that, the LacR gene, which is downstream of rcfB will be highly transcribed. The large translation of LacR, the repressor of lac operon in Lactobacillus delbrueckii, will inhibit the use of lactose in the bacteria.
Sequence and Features
- 10COMPATIBLE WITH RFC
- 12COMPATIBLE WITH RFC
- 21COMPATIBLE WITH RFC
- 23COMPATIBLE WITH RFC
- 25Illegal NgoMIV site found at 31
Illegal NgoMIV site found at 934
- 1000Illegal BsaI.rc site found at 871
Illegal SapI.rc site found at 600
Verification by A11Sg-AHPMprotein expression
First, we constructed a vector that regulates the expression of a protein of interest through the PrcfB promoter. The vector has the characteristic that when the pH is less than 5.5, the PrcfB promoter strongly expresses the LacR, and the LacR binds to the O1/O2 site to repress the production of the target protein. When the pH is greater than 5.5, the PrcfB promoter is weakly expressed, and the protein of interest can be expressed without being repressed. Fig 1 shows the regulation mechanism.
- Madsen S M, Arnau J, Vrang A, et al. Molecular characterization of the pH-inducible and growth phase-dependent promoter P170 of Lactococcus lactis. Molecular Microbiology, 1999, 32(1):75-87.
- Søren M. Madsen, Thomas Hindré, Jean-Paul Le Pennec, et al. Two acid-inducible promoters from Lactococcus lactis require the cis-acting ACiD-box and the transcription regulator RcfB. Molecular Microbiology, 2005, 56(3):735-746.
- Ismail AKYOL, Ugur COMLEKCIOGLU, Asuman KARAKAS, Kalbiye SERDAROGLU, Mehmet Sait EKINCI, Emin OZKOSE. Regulation of the acid inducible rcfB promoter in Lactococcus lactis subsp. Lactis. Annals of Microbiology, 2008, 58 (2) 269-273.