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Team:Grenoble/Biology/Network
From 2012.igem.org
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cAMP binds to CRP (C-reactive protein) and then this complex allows the production of AraC by activating the pMalT promoter.<br/> | cAMP binds to CRP (C-reactive protein) and then this complex allows the production of AraC by activating the pMalT promoter.<br/> | ||
| - | In the presence of arabinose, AraC, with cAMP-CRP, activates the pAraBAD promoter, forming an "AND" gate, which allow the production of: | + | In the presence of arabinose, AraC, with cAMP-CRP, activates the pAraBAD promoter, forming thus an "AND" gate, which allow the production of: |
| - | <ul><li>adenyl cyclase which reproduce cAMP, forming an amplification loop | + | <ul><li>adenyl cyclase which reproduce cAMP, forming thus an amplification loop |
<li>GFP (Green Fluorescent Protein) = our output signal | <li>GFP (Green Fluorescent Protein) = our output signal | ||
</ul> | </ul> | ||
<br/> | <br/> | ||
| - | + | When one bacterium detecte <i>S. aureus</i>, it produces a lot of GFP and cAMP. cAMP can diffuse through the membrane and activates the amplification loop in all the neighbourings bacteria which can thus produce a lot of GFP and cAMP.<br/> | |
| + | The result is an entire population which produce GFP whereas only one bacterium has detected the pathogen in the first place. | ||
</section> | </section> | ||
Revision as of 22:36, 23 September 2012
Network details
Our system is divided in two modules:- signaling module
- amplification module
Signaling module
The signaling module allows our bacterial strain to integrate the input signal = the pathogene presence.
Stapylococcus aureus secrete a protease nom de la protéase which cut a specific amino-acids sequence. This specific sequence can be used as a linker between a membrane protein and a dipeptide.
Once S. aureus is present, the linker is cut by the protease and the dipeptide is released.
The dipeptide binds to his receptor which is an engineered receptor:
- the extracellular part is the extracellular part of Tap, a dipeptide receptor involved in the chemotaxism
- the intracellular part is the intracellular part of EnvZ, a kinase involved in the osmoregulation
Once the dipeptide is bound, the EnvZ part allows the phosphorylation of OmpR, a transcriptional activator.
Amplification module
The amplification module allows our bacterial strain to amplify the input signal and to produce an output signal = fluorescence.
Once OmpR is phosphorylated, it allows the production of adenyl cyclase by activating the OmpC promoter.
Adenyl cyclase is an enzyme which catalyse the conversion of ATP (Adenosine Tri-Phosphate) to cAMP (cyclic Adenosine Mono-Phosphate).
cAMP binds to CRP (C-reactive protein) and then this complex allows the production of AraC by activating the pMalT promoter.
In the presence of arabinose, AraC, with cAMP-CRP, activates the pAraBAD promoter, forming thus an "AND" gate, which allow the production of:
- adenyl cyclase which reproduce cAMP, forming thus an amplification loop
- GFP (Green Fluorescent Protein) = our output signal
When one bacterium detecte S. aureus, it produces a lot of GFP and cAMP. cAMP can diffuse through the membrane and activates the amplification loop in all the neighbourings bacteria which can thus produce a lot of GFP and cAMP.
The result is an entire population which produce GFP whereas only one bacterium has detected the pathogen in the first place.
