Part:BBa_K1846005
cI-Cro bacteriophage lambda lytic cycle regulatory circuit
The cI-Cro construct contains a circuit for the production - via a constitutive promoter - of the cI repressor protein (also known as the Lambda Repressor), which is responsible for keeping bacteriophage lambda in the lysogenic cycle through the cooperative binding of two repressor dimers to the DNA, repressing the Cro gene. The circuit uses a T7 promoter to drive the expression of the Cro gene in the opposite direction to the cI gene, essentially silensing the expression of the cI gene. Thus, the presence of the T7 RNA polymerase in the system enables the switch from the lysogenic cycle to the lytic cycle.
We characterised this construct by analysing the soluble protein fraction of the cell lysate (Figure 3). As cI protein is produced constitutively in our circuit, we expected to see a cI protein band at ca 26 kDa (cI = 237 aa, MW: 26211.8 Da). Our control E.coli 10β cells containing the cI/cro construct are showing the expected bands at ca 26 kDa, Figure 3, samples 7, 8 and 9. We attribute lack of cI bands in our T7 Express cell lysate, sample 4 Figure 3, due to T7 RNAP leakage, which would silence the cI expression. This hypothesis requires further investigation, however our preliminary results suggest the circuit would be functional.
http://2015.igem.org/File:BBKiGEM-SDSgel-Figure_3.jpg
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]
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