Part:BBa_K2270005

gal promoter from Lactococcus lactis

Promoter of the gal operon from Lactoccocus lactis, repressed by glucose. Contains the cre site for catabolite repression in gram-positive bacteria.

Usage and Biology

This promoter is controlled by the carbon catabolite repression system (CCR). In gram-positive bacteria, as L. lactis, the CCR is mediated by the carbon catabolite control protein A (CcpA). To cause CCR, CcpA must bind to a specific palindromic sequence in the promoters regions of catabolic operons, called catabolite responsive elements (cre sites). When there's glucose in the media, the CcpA binds to the cre site and blocks the gene expression.

By these results in our experiment (https://parts.igem.org/Part:BBa_K2270008), we can see that the gal promoter is indeed repressed by the presence of glucose, that because in the experiments using glucose and fructose, we can see a high fluorescene signal, which means that the promoter was repressed and so was the sRNA, allowing the production of GFP. For the promoter activation, we can see that in the experiments using mannitol and galactose as carbon source, we noticed a low fluorescence signal which means that the promoter was active and the sRNA were being expressed, blocking the production of GFP.

Thus, with this experiment we were able to do a simple characterization of this promoter and prove that it is regulated by the carbon catabolite repression, being a useful part to construct circuits regulated by the carbon source.

[1] Zomer et al. Time-Resolved Determination of the CcpA Regulon of Lactococcus lactis subsp. cremoris MG1363. Journal of Bacteriology. vol. 189, p. 1366-1381. American Society for Microbiology, 2007.

[2] Görke, B.; Stülke, J. Carbon catabolite repression in bacteria: many ways to make the mos out of nutrients. Nature Reviews: Microbiology. vol. 6, p. 613-624. Macmillan Publishers Ltd, 2008.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]