Part:BBa_K2270008
galP-sRNA-rrnb(Bs)
Small RNA for post-transcritional control of gene expression, under the control of the gal operon promoter repressed by glucose.
Usage and Biology
This is the complete device that we used to control the gene expression by glucose in our project. We used this device to invert the signal of the carbon catabolite repression in L. lactis. 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.
We associated the gal promoter from L. lactis (https://parts.igem.org/Part:BBa_K2270005) with the our designed sRNA (https://parts.igem.org/Part:BBa_K2270006) to create a inverter to the CCR signal, that way, when there's glucose, the gene will be expressed, and when there's no glucose, the gene expression is off.
In order to test our device, we grew Lactococcus lactis transformed with it in M17 media supplemented with different carbon sources, glucose, fructose, mannitol and galactose, and measured the fluorescence. Data shown below.
After analysing the graphic, we can admit that glucose and fructose presence “turned ON” the gene reporter expression, showing similar relative fluorescence values to the control. Meanwhile, when exposed to other carbon sources, such as mannitol and galactose, the gene reporter expression was “turned OFF”, presenting then lower relative fluorescence values, when compared with the control. This result shows that the sRNA design was successful, but further characterization should be executed for better understanding.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
//collections/probiotics/control
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